Windward Bio Group: DRS filing (amended)

Cover page 13 changes

As confidentially submitted to the U.S. Securities and Exchange Commission on September 21, 2026. October 13,

This Amendment No. 2 3 to the draft registration statement has not been filed publicly with the U.S. Securities and Exchange Commission and all information contained herein remains confidential.

Exchange Commission and all information contained herein remains confidential.

Registration Statement No. 333-

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Amendment No. 2 to Form F-1

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Niederer Kraft Frey AG

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Summary—Implications of Being a Foreign Private Issuer."

Investing in our common shares involves a

a high degree of risk. Before buying any common shares, you should carefully read the discussion of material risks of investing in our common shares in " Risk Factors " beginning on page 16 17 of this prospectus.

We are both an "emerging growth company" and a "foreign private issuer" under applicable rules of the U.S. Securities and Exchange

Securities and Exchange Commission, or the SEC, and are eligible for reduced public company disclosure requirements. See "Prospectus Summary—Implications of Being an Emerging Growth Company" and "Prospectus Summary—Implications of Being a

Foreign Private Issuer."

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INDEX TO CONSOLIDATED CONDENSED CONSOLIDATED INTERIM FINANCIAL STATEMENTS

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About this prospectus 1 change

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This prospectus includes trademarks, tradenames trade names and service marks, certain of which belong to us and others that are the property of other organizations. Solely for convenience, the trademarks, trade names and service marks may appear in this prospectus without the and TM symbols, but any such references are not intended to indicate, in any way, that we or their respective owners forgo or will not assert, to the fullest extent under applicable law, our or their respective owners' rights or the rights of the applicable licensors to these trademarks, trade names and service marks. We do not intend to use or display other companies' trademarks and trade names to imply a relationship with, or endorsement or sponsorship of us by, any other companies.

Presentation of financial information 4 changes

This prospectus includes our audited annual consolidated financial statements as of December 31, 2025 and 2024 and for the year ended December 31, 2025 and for the period from July 5, 2024 (inception) to December 31, 2024, which have been prepared in accordance with IFRS Accounting Standards, or IFRS, as issued by the International Accounting Standards Board, or IASB. This prospectus also includes our unaudited interim condensed consolidated interim financial statements as of June 30, 2026 and for the six months ended June 30, 2026 and 2025, prepared under the International Accounting Standard 34, or IAS 34. None of our financial statements were prepared in accordance with generally accepted accounting principles in the United States, or U.S. GAAP.

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are to U.S. dollars and all references to "CHF" mean Swiss francs. Unless otherwise indicated, for the convenience of the reader, all CHF amounts contained in this prospectus have been translated into U.S. dollars at the rate of CHF1.00 CHF 1.00 to $ , $1.2372, which was the noon buying rate of the Federal Reserve Bank of New York on June 30, 2026. These translations should not be considered representations that any such amounts have been, could have been or could be converted into CHF at that or any other exchange rate as of that or any other date.

We have made rounding adjustments to some of the figures included in this prospectus. Accordingly, numerical figures shown as totals in some tables may not be an arithmetic aggregation of the figures that preceded them.

Accordingly, numerical figures shown as totals in some tables may not be an arithmetic aggregation of the figures that preceded them.

Prospectus summary 65 changes

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WIN378 is an ultra-long-acting and potentially novel fully human monoclonal antibody that is designed to inhibit thymic stromal lymphopoietin, or TSLP. TSLP is positioned upstream of multiple inflammatory pathways and is a clinically validated target in respiratory disease. WIN378 is currently being evaluated in POLARIS-1, a Phase 2/3 study in severe uncontrolled asthma. Study start-up activities were initiated in September 2026 for a second Phase 3 asthma study (POLARIS-2), which is planned and to begin patient recruitment in the first half of 2027. A Phase 2 study of WIN378 in COPD, SIRIUS, was initiated in June 2026. A pre-planned analysis of the Phase 2 portion of POLARIS-1 was completed in the second half of 2026. This model-informed Phase 2 portion characterized the dose-response relationship and enrolled 147 patients, exceeding the enrollment target of 120 patients. WIN378 was well-tolerated, with favorable safety results — there were no treatment-related serious adverse events, withdrawals or discontinuations observed to date. Adverse events were balanced between active arms and placebo, with low rates of injection site reactions and antidrug antibodies. WIN378 had an observed half-life of up to 75 days and produced improvements in lung function and biomarkers of airway inflammation at week 24, which we believe support twice-yearly subcutaneous dosing and the potential for improved clinical outcomes. Two twice-yearly dose levels were selected, and the Phase 3 portion of POLARIS-1 was initiated in September 2026. We expect that the next data readout for WIN378 will be the Phase 2 primary results at week 24 in the first half of 2027.

WIN378 had an observed half-life of up to 75 days and improvements in lung function and biomarkers of airway inflammation at week 24 were observed, which we believe support twice-yearly subcutaneous dosing and the potential for improved clinical outcomes. Two twice-yearly dose levels were selected, and the Phase 3 portion of POLARIS-1 was initiated in September 2026. We expect that the next data readout for WIN378 will be the Phase 2 primary results at week 24 in the first half of 2027.

WIN027 is an ultra-long-acting bispecific antibody that simultaneously targets TSLP and interleukin-13, or IL-13, two clinically validated drivers of inflammatory disease. We believe that dual inhibition of these pathways has the potential to deliver deeper and more durable disease control than targeting either pathway alone. WIN027 is currently in a Phase 1 healthy volunteer study with investigational new drug applications, or INDs, open in the United States, Australia and the People's Republic of China, or the PRC, assessing safety and pharmacokinetics. In an interim analysis of the Phase 1 study, we observed a 62-day half-life, low immunogenicity and favorable safety results, low rate of injection site reactions, with full pharmacokinetic and immunogenicity data expected in the first half of 2027. We plan to initiate initiated study start-up activities in September 2026 in a global Phase 2 2b study in COPD fully powered on the registrational endpoint of exacerbation rate ratio and a second global Phase 2 study in atopic dermatitis, which are planned to begin patient recruitment in the first half of 2027. Additionally, based on Our knowledge, our partner Qyuns Therapeutics Co., Ltd., or Qyuns, is planning to conduct initiated their Phase 2 studies in asthma, atopic dermatitis and chronic rhinosinusitis with nasal polyps, or CRSwNP, and atopic dermatitis in September 2026 in the PRC and plans to begin a Phase 2 study in asthma by the second half end of 2026, with the year. Topline results from these studies are expected in over the course of 2027 and 2028.

Our goal is to develop, obtain regulatory approval, and

regulatory approval, and commercialize potentially novel immunology therapeutics for patients underserved by today's standard of care in asthma, COPD, atopic dermatitis, and other immunological conditions. Key elements of our novel approach, which we believe has the potential to improve the outcomes of the current generation of biologics in inflammatory lung and skin diseases for these patients, are below.

We target clinically validated biologic drivers of disease including TSLP and IL-13.

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Our mission is to transform the treatment paradigm for

is to transform the treatment paradigm for patients living with chronic inflammatory diseases through the development of differentiated biologic therapies targeting validated disease pathways. Our products have the potential to address a broad range of patient types and offer more convenient dosing regimens that can improve adherence to treatment and deliver enhanced real-world outcomes. The key elements of our strategy include:

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Windward Bio holds global rights to WIN378 excluding Greater China and certain Asian markets ** Exclusivity based on pending applications and anticipated patent extensions *** Asthma and CRSwNP Phase 2 studies are planned in the PRC only, conducted and funded by Qyuns Therapeutics; see "—WIN027" on page 5 for more information **** Lead optimization stage with potential in respiratory and dermatology; see "—Additional bispecific programs" on page 5 for more information IP=intellectual property, mAb=monoclonal antibody WIN378 is an ultra-long-acting and potentially novel fully human monoclonal antibody that is designed to inhibit the TSLP ligand. WIN378 has been engineered to achieve half-life extension and silenced effector function. In preclinical nonclinical studies, WIN378 has been observed to have greater potency than the currently approved anti-TSLP treatment, has two binding sites to TSLP and fully overlaps the same binding site as Tezspire , tezepelumab. WIN378 has been studied in a Phase 1 trial, which evaluated an extended half-life that we believe may support twice-yearly dosing, demonstrated a low rate of antidrug antibodies, and was well tolerated up to the highest dose tested.

WIN378 is currently being evaluated in

in POLARIS-1, a Phase 2/3 study in severe, uncontrolled asthma. A pre-planned interim analysis from the Phase 2 portion of the study was completed in the second half of 2026. Following dose selection based on the interim analysis, we initiated the Phase 3 portion of POLARIS-1 in September 2026, with topline results expected in the second half of 2028. and we also plan to initiate Study start-up activities were initiated in September 2026 for a second Phase 3 study (POLARIS-2), which is planned to begin patient recruitment in the first half of 2027 with topline results expected in the second half of 2029. Separately, a Phase 2 study of WIN378 in COPD, SIRIUS, was initiated in June 2026 and we expect topline results in the second half of 2027. We have observed the following results in the Phase 1 clinical trial for WIN378: an extended half-life supporting twice-yearly subcutaneous dosing, a low rate of antidrug antibodies, and favorable safety and tolerability results up to the highest dose tested. no treatment-related serious adverse events were observed. The pre-planned interim analysis of the Phase 2 portion of POLARIS-1 demonstrated the following results:

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WIN378 was well tolerated with favorable safety results—there were no treatment-related serious adverse events, withdrawals or discontinuations observed to date;

WIN378 was well tolerated—there were no treatment-related serious adverse events, withdrawals or discontinuations observed to date: adverse events were balanced between active arms and placebo, with low rates of injection site reactions (<1%) and antidrug antibodies (2.2%).

While these results may not translate to

results may not translate to similar safety or efficacy results in the ongoing Phase 3 portions of our POLARIS studies in patients with asthma or our SIRIUS Phase 2 study in patients with COPD, we believe WIN378 is differentiated from currently approved treatments primarily through its potential for twice-yearly subcutaneous dosing.

Based on published and public statements from other companies as well as results from trials to date in which WIN378 was well tolerated in patients and no serious adverse events deemed to be study-related were reported, we believe that WIN378, if it produces favorable the safety and efficacy data needed to support approval in future pivotal trials, has the potential to be the first ultra-long-acting treatment targeting TSLP to seek approval in the United States. However, the results from early trials of a product candidate may not be predictive of the results that will be obtained in later stage trials of the product candidate.

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WIN027 is currently in a Phase 1 healthy

We have licensed global rights (excluding Greater China) for WIN027 from Qyuns and have the right to use and reference Qyuns' data in connection with our development of WIN027 and our pursuit and maintenance of regulatory approvals outside Greater China. For more information, see the section titled "Business—Intellectual Property" included elsewhere in this prospectus.

WIN027 is currently in a Phase 1 healthy volunteer study with INDs open in the United States, Australia and the PRC assessing safety and pharmacokinetics. Based on blinded interim data as of June 2026, we have observed a 62-day half-life, low immunogenicity and favorable safety results, low rate of injection site reactions, with full pharmacokinetic and immunogenicity data expected in the first half of 2027. If successful, We plan to initiate initiated study start-up activities in September 2026 for a global Phase 2 2b study in COPD, fully powered on the registrational endpoint of exacerbation rate ratio, as well as a global Phase 2 study in atopic dermatitis, which are planned to begin patient recruitment in the first half of 2027.

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AD=atopic dermatitis, COPD=chronic obstructive pulmonary disease, HV=healthy volunteer, TLR=topline results, W=week; remaining studies, not funded by the expected IPO proceeds, are already funded Additional bispecific programs are in the lead optimization phase. The current program is a next-generation bispecific targeting T2 and non-T2 pathways, with two complementary cytokines. Work to date has included the evaluation of various formats, production at small scale, and the evaluation of productivity, purity and light chain mispairing. Further work has characterized the blocking of both cytokines and a HELA cell-based potency assay has been developed and used to compare the bispecifics' potencies to monospecific benchmarks. Of the three formats evaluated, a lead pre-clinical nonclinical target format has been identified and selected, with potential across skin and respiratory indications, including atopic dermatitis, asthma, COPD and other inflammatory and fibrotic skin and lung diseases. We expect to initiate Phase 1 clinical development for these potential skin and respiratory indications in the next 18 months, subject to standard regulatory requirements. The lead format demonstrating benchmark-comparable affinity, cellular potency and manufacturability is currently being engineered for half-life extension prior to characterization in nonhuman primate studies.

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Our management team is led by our founder, Chief Executive Officer and Chairman, Luca Santarelli, M.D., who has more than 25 years of academic and biopharmaceutical research and development experience and previously co-founded and served as Chief Executive Officer of VectivBio, which was acquired by Ironwood Pharmaceuticals in 2023 for $1.2 billion, and Therachon, which was acquired by Pfizer in 2019 for up to $810 million.

To date, Windward Bio has raised up to

To date, Windward Bio has raised up to $365.0 million by way of equity financings, led by top-tier global healthcare investors including OrbiMed, Novo Holdings, SR One, Omega Funds, Blue Owl Healthcare Opportunities and RTW Investments. Prospective investors should not rely on the investment decisions of our existing investors, as these investors may have different risk tolerances and have received their shares in prior offerings at prices lower than the price offered to the public in this offering. See "Related Party Transactions" for more information.

Prospective investors should not rely on the investment decisions of our existing investors, as these investors may have different risk tolerances and have received their shares in prior offerings at prices lower than the price offered to the public in this offering. See "Related Party Transactions" for more information.

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Our business is subject to numerous

Our business is subject to numerous risks and uncertainties of which you should be aware before making an investment decision. You should carefully consider all of the information set forth in this prospectus and, in particular, evaluate the specific factors set forth in the section titled "Risk Factors" before making an investment decision. These risks include, but are not limited to, the following:

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If our clinical trials fail to replicate positive results from earlier preclinical nonclinical studies or clinical trials conducted by us or third parties, we may be unable to successfully develop, obtain regulatory approval for or commercialize WIN378, WIN027 or any other potential future product candidates;

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Even if we complete the necessary preclinical nonclinical studies and clinical trials, the marketing regulatory approval process is expensive, time-consuming and uncertain and may prevent us from obtaining approvals for the commercialization of our product candidates;

We are dependent on third parties having accurately generated, collected and reported data from certain preclinical nonclinical studies that were previously conducted for WIN378 and WIN027;

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Our success and our future growth depends depend in part on attracting, hiring and retaining our key personnel and recruiting additional qualified personnel;

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(iii) the date that we become a "large accelerated filer" as defined in Rule 12b-2 under the Exchange Act, which would occur if the market value of our common shares that is held by non-affiliates exceeds $700 $700.0 million as of the last business day of our most recently completed second fiscal quarter; or (iv) the date on which we have issued more than $1 billion in non-convertible debt securities during any three-year period.

We have taken advantage of certain reduced reporting

We have taken advantage of certain reduced reporting requirements in this prospectus. Accordingly, the information contained herein may be different than the information you receive from other public companies in which you hold equity securities registered under the Exchange Act. As an emerging growth company we can also delay adopting new or revised financial accounting standards until such time as those standards apply to private companies. We may take advantage of this extended transition period under the JOBS Act for adopting new or revised financial accounting standards.

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Our status as a foreign

Our status as a foreign private issuer also exempts us from compliance with certain laws and regulations of the SEC and certain regulations of the Nasdaq Global Market, or Nasdaq. Consequently, we are not subject to all of the disclosure requirements applicable to U.S. public companies. For example, we are exempt from certain rules under the Exchange Act that regulate disclosure obligations and procedural requirements related to the solicitation of proxies, consents or authorizations applicable to a security registered under the Exchange Act. Our executive officers, directors and principal shareholders are also exempt from the "short-swing" profit recovery provisions of Section 16(b) of the Exchange Act. Moreover, we are not required to file periodic reports and financial statements with the SEC as frequently or as promptly as U.S. public companies. Accordingly, there may be less publicly available information concerning our company than there is for U.S. public companies.

Accordingly, there may be less publicly available information concerning our company than there is for U.S. public companies.

In addition, foreign private issuers

In addition, foreign private issuers are not required to file their annual report on Form 20-F until four months after the end of each fiscal year, while U.S. domestic issuers that are accelerated filers are required to file their annual report on Form 10-K within 75 days after the end of each fiscal year. Foreign private issuers are also exempt from the Regulation Fair Disclosure, aimed at preventing issuers from making selective disclosures of material information. Additionally, Nasdaq rules allow foreign private issuers to follow home country practices in lieu of certain of Nasdaq corporate governance rules. As a result, our shareholders may not have the same protections afforded to shareholders of companies that are subject to all Nasdaq corporate governance requirements.

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Approximately $ million to fund the completion of our ongoing

Approximately $ million to fund our bispecific programs; and

Approximately $ million to fund the completion of (i) our ongoing POLARIS-1 Phase 2/3 trial and a confirmatory POLARIS-2 Phase 3 trial of WIN378 in asthma; (ii) the completion of our ongoing SIRIUS Phase 2 trial of WIN378 in COPD; and (iii) related research and development activities, including clinical development, regulatory affairs, quality, research, translational sciences, clinical supply, and drug substance and drug product manufacturing;

Approximately $ million to fund the completion of (i) our planned global Phase 2b trial of WIN027 in COPD; (ii) our planned global Phase 2 trial of WIN027 in atopic dermatitis; and (iii) related research and development activities, including clinical development, regulatory affairs, quality, research, translational sciences, clinical supply, and drug substance and drug product manufacturing;

Approximately $ million to fund the advancement of our bispecific programs through the completion of IND-enabling studies; and ∎ The remainder for working capital and general corporate purposes, including personnel costs, facilities, and other operational expenses.

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The number of common shares to be outstanding after the offering is based on 15,491,686 common shares (including 6,797,703 restricted shares subject to repurchase rights based on continued service requirements and 1,133,155 restricted shares subject to repurchase rights that lapse if this offering closes), 31,897,927 Series A preferred shares, 5,582,139 Series A junior preferred shares, and 15,948,971 Series B preferred shares outstanding as of June 30, 2026 and 397,495 common shares reserved for future issuance as of June 30, 2026 related to the warrants issued in connection with our Series B financing, or the Series B Warrants, and excludes:

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50,700 common shares we hold in treasury; and

397,495 common shares reserved for future issuance as of June 30, 2026 related to the warrants issued in connection with our Series B financing, all of which will be issued prior to the completion of our initial public offering.

Unless otherwise indicated, all

common shares that are reserved for future issuance issuable upon exercise or settlement of awards pursuant to our 2026 Equity Incentive Plan, or the 2026 Plan, as more fully described in the section titled "Management—Equity Incentive Plans;" Plan";

common shares reserved for issuance issuable under our 2026 Employee Share Purchase Plan, or the ESPP; and ∎ 50,700 common shares we hold in treasury.

Unless otherwise indicated, all information contained in this prospectus also reflects and assumes:

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no issuance or exercise of outstanding options or settlement of outstanding restricted share units after June 30, the conversion settlement of all of our 397,495 outstanding preferred shares into 53,429,037 Series B Warrants for common shares immediately prior to the completion of this offering (based on a cashless exercise), or the Preferred Share Conversion; Series B Warrant Settlement;

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The pro forma basic and diluted net loss per share gives effect to the Preferred Share Conversion immediately prior to the completion of this offering as if they had been converted to ordinary shares at the beginning of the earliest period presented. Common shares to be sold in this offering are excluded from the calculation.

Consolidated Statement of Profit or Loss and Other Comprehensive Loss Data (in thousands, except for share and per share data) FOR THE YEAR ENDED DECEMBER 31, 2025 FOR THE PERIOD FROM JULY 5, 2024 TO DECEMBER 31, 2024 FOR THE SIX MONTHS ENDED JUNE 30, 2026 2025 Research and development expenses $ (32,592 ) $ (84 ) $ (30,133 ) $ (13,325 ) General and administrative expenses (19,237 ) (1,104 ) (14,539 ) (9,951 ) Operating loss (51,829 ) (1,188 ) (44,672 ) (23,276 ) Financial income 3,593 — 2,164 Financial expense (5 ) — (7 ) (2 ) Foreign exchange differences, net (34 ) — (166 ) (145 ) Loss before income taxes (48,275 ) (1,188 ) (42,681 ) (22,750 ) Income taxes (48 ) — — Net loss (48,323 ) (1,188 ) (42,636 ) (22,750 ) Total comprehensive loss (49,447 ) (1,188 ) (42,640 ) (23,216 ) Net loss attributable to common shareholders, Basic and diluted $ $ $ $ Basic and diluted loss per share (1) $ (7.44 ) $ (0.12 ) $ (5.28 ) $ (4.03 ) Weighted-average common shares outstanding, basic and diluted (1) Pro forma net loss per share, basic and diluted $ $ Pro forma weighted-average common shares outstanding, basic and diluted (2) (1) See Note 22 to our audited consolidated financial statements included elsewhere in this prospectus for further details regarding the calculation of basic and diluted loss per share.

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(in thousands, except for share data)

Cash, cash equivalents and marketable securities

Marketable securities are comprised of current and non-current financial assets at Fair Value Through Profit or Loss, or FVTPL. See note 6 to our unaudited condensed consolidated interim financial statements included elsewhere in this prospectus for further details regarding cash, cash equivalents and marketable securities as of June 30, 2026.

Forma as Adjusted Data

Cash, cash equivalents and marketable

Gives effect to (i) the filing and effectiveness of the amendment and restatement of our articles of association immediately prior to the completion of this offering, and (ii) the Preferred Share Conversion and (iii) the Series B Warrant Settlement immediately prior to the completion of this offering.

Gives further effect to the sale of common shares in this offering at the assumed initial public offering price of $ per common share, which is the midpoint of the price range set forth on the cover page of this prospectus, after deducting the estimated underwriting discounts and commissions of $ and estimated offering expenses payable by us of $ .

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Marketable securities are comprised of current and non-current financial assets at FVTPL. See note 6 to our unaudited condensed consolidated interim financial statements included elsewhere in this prospectus for further details regarding cash, cash equivalents and marketable securities as of June 30, 2026.

DECEMBER 31, 2025 (1)

Net loss per share, basic and diluted

Weighted-average common shares outstanding, basic and diluted (1)

The pro forma basic and diluted net loss per share gives effect to (i) the filing and effectiveness of the amendment and restatement of our articles of association, (ii) the Preferred Share Conversion and (iii) the Series B Warrant Settlement immediately prior to the completion of this offering as if they had taken place at January 1, 2025. Common shares to be sold in this offering are excluded from the calculation.

Risk factors 252 changes

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Risks Related to Our Limited Operating History, Financial

History, Financial Condition and Need for Additional Capital

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We are a clinical-stage biopharmaceutical company with

We are a clinical-stage biopharmaceutical company with a limited operating history. We were formed in July 2024 and began operations in January 2025 and our operations to date have been limited to pre-commercial activities. We have not yet demonstrated an ability to generate revenues, obtain regulatory approvals, manufacture any product on a commercial scale or arrange for a third party to do so on our behalf or conduct sales and marketing activities necessary for successful product commercialization. Our limited operating history as a company makes any assessment of our future success and viability subject to significant uncertainty. We will encounter risks and difficulties frequently experienced by early-stage biopharmaceutical companies in rapidly evolving fields, and we have not yet demonstrated an ability to successfully overcome such risks and difficulties. If we do not address these risks and difficulties successfully, our business will suffer.

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We have no products approved for commercial sale and have not generated any revenue from product sales to date. We have two clinical-stage antibody product candidates targeting the TSLP signaling pathway: WIN378, our lead product candidate, and WIN027. Beyond WIN378 and WIN027, we are building a discovery pipeline of long-acting bispecific antibodies targeting validated biology in respiratory and dermatological conditions. We will continue to incur significant research and development and other expenses related to our preclinical nonclinical and clinical development of WIN378 and WIN027 and ongoing operations. As a result, we are not profitable and have incurred losses in each period since our inception. Net losses and negative cash flows have had, and will continue to have, an adverse effect on our shareholders' deficit total equity and working capital. Our net losses totaled amounted to $48.3 million for the year ended December 31, 2025 and $1.2 million for the period from our incorporation to December 31, 2024, respectively. As of December 31, 2025, we had an accumulated deficit losses of $50.6 million. For the six months ended June 30, 2026, we incurred a net loss of $42.6 million. As of June 30, 2026, we had an accumulated deficit losses of $93.2 million. We expect to continue to incur significant losses for the foreseeable future, and we expect these losses to increase as we continue our research and development of, and seek regulatory approvals for, WIN378 and WIN027 in multiple indications.

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Developing biopharmaceutical products, including conducting preclinical nonclinical studies and clinical trials, is a time-consuming, expensive and uncertain process that takes years to complete. We expect our expenses to continue to increase in connection with our ongoing activities, particularly as we conduct clinical trials of, and seek regulatory approval for, WIN378, WIN027 or our potential future product candidates in multiple indications and commence additional clinical trials. Even if WIN378, WIN027 or our potential future product candidates are approved for commercial sale, we anticipate incurring significant costs associated with commercializing any approved product candidate. To date, we have funded our operations solely through private financings.

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marketable securities in the amount of $207.3 million. Based upon our current operating plan, we believe that the net proceeds from this offering together with our existing cash, cash equivalents and marketable securities will enable us to fund the completion of our ongoing POLARIS-1, our ongoing Phase 2/3 pivotal clinical trial and our confirmatory POLARIS-2 Phase 3 trial evaluating of WIN378 in patients with moderate-to-severe uncontrolled asthma, fund the completion of our planned global Phase 2b study for trial of WIN027 in COPD, planned global Phase 2 trial of WIN027 in atopic dermatitis, the advancement of our bispecific programs through the completion of IND-enabling studies, and our operating expenses and capital expenditure requirements through . We have based this estimate on assumptions that may prove to be wrong, and we could expend our available capital resources sooner than we expect. We may also raise additional financing on an opportunistic basis in the future. For example, we may seek additional capital due to favorable market conditions or strategic considerations even if we believe we have sufficient funds for our current or future operating plans. Attempting to secure additional financing may divert our management from our day-to-day activities, which may adversely affect our ability to develop WIN378, WIN027 or our potential future product candidates. Our future capital requirements will depend on many factors, including but not limited to:

Attempting to secure additional financing may divert our management from our day-to-day activities, which may adversely affect our ability to develop WIN378, WIN027 or our potential future product candidates. Our future capital requirements will depend on many factors, including but not limited to:

the scope, timing, progress, costs and results of the ongoing development of WIN378 and WIN027 as well as for potential discovery, preclinical nonclinical development and clinical trials for other potential future product candidates;

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We are dependent on third parties

We are dependent on third parties having accurately generated, collected and reported data from certain preclinical nonclinical studies that were previously conducted for WIN378 and WIN027.

We currently have two product candidates, WIN378 and WIN027, both of which we licensed from third-party biotechnology companies. Kelun and HBM granted us an exclusive, worldwide (excluding certain Asian countries and territories, such excluded countries including Greater China, which are reserved to Kelun and HBM) license to manufacture, develop, use, promote, sell, offer for sale, import and otherwise commercialize WIN378, pursuant to a License and Collaboration Agreement dated December 31, 2024, or the Kelun-HBM Agreement. Additionally, Qyuns granted us an exclusive, worldwide (excluding Greater China) license to develop, use, promote, sell, offer for sale, import and otherwise commercialize WIN027 pursuant to a License and Collaboration Agreement dated December 19, 2025, or the Qyuns Agreement and, together with the Kelun-HBM Agreement, the License Agreements. Our business presently depends entirely on our ability to successfully develop, obtain regulatory approval for, and commercialize WIN378 and WIN027 for one or more of the indications that we are pursuing in a timely manner. The failure of either WIN378 or WIN027 would impose an adverse effect on our business and adversely affect regulatory confidence in and the clinical development of our product candidates.

In addition, our assumptions about the development potential of WIN378 are substantially based on the data generated from preclinical nonclinical and clinical studies, including the Phase 1 clinical data, conducted by Kelun and HBM pursuant to the Kelun-HBM Agreement. In contrast, our assumptions about the development potential of WIN027 are based more substantially on preclinical nonclinical and early clinical data generated by Qyuns prior to the Qyuns Agreement, as our own clinical development program for WIN027 remains at an earlier stage. We are dependent on Kelun and Qyuns having conducted their research and development in accordance with the applicable protocols, informed consent, legal and regulatory requirements, and scientific standards; having accurately reported the results of all preclinical nonclinical and clinical studies conducted with respect to WIN378 and WIN027 and having correctly collected the data and regulatory materials from these studies. If these activities were not compliant, accurate or correct, the clinical development, regulatory approval or commercialization of WIN378 and WIN027 in the United States and other jurisdictions outside of the licensors' retained territories will be adversely affected. Furthermore, we may observe materially and adversely different results as we continue to conduct our clinical trials, including with respect to WIN378, our ongoing Phase 2/3 POLARIS study in asthma and the Phase 2 SIRIUS study in COPD, and our ongoing Phase 1 clinical study for WIN027 and planned future studies in atopic dermatitis and COPD. If we are unable to develop, receive regulatory approval for and successfully commercialize WIN378 or WIN027, or if we experience delays as a result of any of the above factors or otherwise, our business would be significantly harmed.

If these activities were not compliant, accurate or correct, the clinical development, regulatory approval or commercialization of WIN378 and WIN027 in the United States and other jurisdictions outside of the licensors' retained territories will be adversely affected. Furthermore, we may observe materially and adversely different results as we continue to conduct our clinical trials, including with respect to WIN378, our ongoing Phase 2/3 POLARIS study in asthma and the Phase 2 SIRIUS study in COPD, and our ongoing Phase 1 clinical study for WIN027 and planned Phase 2 studies in atopic dermatitis and COPD. If we are unable to develop, receive regulatory approval for and successfully commercialize WIN378 or WIN027, or if we experience delays as a result of any of the above factors or otherwise, our business would be significantly harmed.

If we are unable to advance WIN378

If we are unable to advance WIN378 and/or WIN027 in clinical development for one or more of the indications that we are pursuing, or to obtain regulatory approval and ultimately commercialize WIN378 and/or WIN027, or experience significant delays in doing so, our business will be materially harmed.

To date, we have not completed the development of any product candidate, and WIN378 and WIN027 remain in clinical development. Our future success and ability to generate revenue depends primarily on our ability to successfully develop, obtain regulatory approval for and commercialize WIN378 and/or WIN027. WIN378, WIN027 and any other potential future product candidates will require substantial additional investment for clinical development, regulatory review and approval in one or more jurisdictions. In particular, any failure of WIN378 and/or WIN027 to receive regulatory approval or achieve commercial success would have an adverse effect on our business. If WIN378, WIN027 or any other potential future product candidates encounter safety or efficacy problems, development delays or regulatory issues or other problems, our development plans and business would be materially harmed.

We may not have the financial resources to continue development of WIN378, WIN027 or any other potential future product candidates if we experience any issues that delay or prevent regulatory approval of, or our ability to commercialize, WIN378, WIN027 or any potential future product candidates, including:

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if our financial and other resources are insufficient to complete the necessary clinical trials and preclinical nonclinical studies;

negative or inconclusive results from our clinical trials, preclinical nonclinical studies or the clinical trials of others for product candidates similar to ours, leading to a decision or requirement to conduct additional clinical trials or preclinical nonclinical studies or abandon a program;

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Successful development of pharmaceutical products involves a lengthy and expensive process, is highly uncertain and is dependent on numerous factors, many of which are beyond our control. Failure can occur at any time during the preclinical nonclinical study or clinical trial process. A number of companies in the pharmaceutical and biotechnology industries have suffered significant setbacks in clinical development even after achieving promising results in earlier studies, and the historical failure rate for product candidates in our industry is high. The results from preclinical nonclinical studies or early clinical trials of a product candidate may not predict the results of later clinical trials of the product candidate, and interim results of a clinical trial are not necessarily indicative of final results. Moreover, preclinical nonclinical and clinical data are often susceptible to varying interpretations and analyses. Product candidates that appear promising in the early phases of development may fail to reach the market for several reasons, including:

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failure to receive the necessary regulatory approvals or a delay in receiving such approvals, which, among other things, may be caused by patients who fail the trial screening process, slow enrollment in clinical trials, patients dropping out of trials, patients lost to follow-up, length of time to achieve trial endpoints, additional time requirements for data analysis or a Biologics License Application, or BLA, or similar foreign application preparation, discussions with the FDA, an FDA request for additional preclinical nonclinical or clinical data (such as long-term toxicology studies) or unexpected safety or manufacturing issues;

preclinical nonclinical or clinical study results may show WIN378, WIN027 or any other potential future product candidates to have harmful side effects;

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The process of obtaining regulatory approvals, both in the United States and abroad, is expensive, may take many years if additional clinical trials are required, if approval is obtained at all, and can vary substantially based upon a variety of factors, including the type, complexity, and novelty of the product candidates involved.

The Company, as an organization, has no experience submitting and supporting the applications necessary to gain regulatory approvals and expect expects to rely on third-party contract research organizations, or CROs, or regulatory consultants to assist us in this process. However, our experienced management team has held leadership positions in drug discovery and development, global commercialization, finance, business development, and corporate strategy spanning multiple therapeutic areas including immunology, and has experience submitting and supporting the applications necessary to gain regulatory approvals. See "Management" for further details on their prior experience. Securing regulatory approval requires the submission of extensive preclinical nonclinical and clinical data and supporting information to the various regulatory authorities for each therapeutic indication to establish the product candidate's safety and efficacy. Securing regulatory approval also requires the submission of information about the product manufacturing process to, and inspection of manufacturing facilities by, the relevant regulatory authority. Any product candidates we develop may not be effective, may be only moderately effective, or may prove to have undesirable or unintended side effects, toxicities or other characteristics that may preclude its obtaining regulatory approval or prevent or limit commercial use.

The process of obtaining regulatory approvals, both in the United States and abroad, is expensive, may take many years if additional clinical trials are required, if approval is obtained at all, and can vary substantially based upon a variety of factors, including the type, complexity, and novelty of the product candidates involved. Changes in regulatory approval policies during the development period, changes in or the enactment of additional statutes or regulations, or changes in regulatory review for each submitted product application, may cause delays in the approval or rejection of an application. The FDA and comparable authorities in other countries have discretion in the approval process and may refuse to accept any application or may decide that our data is insufficient for approval and require additional preclinical, nonclinical, clinical or other studies. In addition, varying interpretations of the data obtained from preclinical nonclinical and clinical testing could delay, limit, or prevent regulatory approval of a product candidate. Any regulatory approval that we may ultimately obtain could be limited or subject to restrictions or post-approval commitments that render the approved product not commercially viable.

Even if we complete the necessary nonclinical studies and

we complete the necessary preclinical studies and clinical trials, the regulatory approval process is expensive, time-consuming and uncertain and may prevent us from obtaining approvals for the commercialization of our product candidates.

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Due to the significant resources required for drug

Due to the significant resources required for drug development and depending on our ability to access capital, we must prioritize the development of WIN378 and WIN027. Moreover, we may fail to expend our limited resources on the development of WIN378 and WIN027 for the treatment of additional indications or for the development of other potential future product candidates that may have been more profitable or for which there is a greater likelihood of success.

Our lead product candidate, WIN378, an ultra-long-acting anti-TSLP monoclonal antibody intended to target a broad range of immunological diseases, including asthma and COPD, is currently being evaluated in a POLARIS Phase 2/3 asthma study and a SIRIUS Phase 2 COPD study. Our initial focus is on developing WIN378 through Phase 3 in asthma and through Phase 2 in COPD for both indications. Our earlier-stage product candidate, WIN027, is currently being evaluated in an ongoing Phase 1 clinical study for WIN027 and planned future Phase 2 studies across respiratory and dermatology indications, including atopic dermatitis and COPD.

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Kelun-HBM Agreement and the Qyuns Agreement, we are obligated to make significant payments to our licensors across the full development and commercialization lifecycle of WIN378 and WIN027. Under the Kelun-HBM Agreement, we may be required to pay Kelun and HBM aggregate development milestone payments of up to $330 $320.0 million (excluding the $10.0 million milestone payments already paid in 2025 and July 2026 in total) for WIN378, aggregate sales milestone payments of up to $600 million per product upon achievement of specified annual net sales thresholds, and low single-digit to low double-digits tiered royalties (a spread of not more than 5 percentage points) on net sales of WIN378 in our licensed worldwide territory (excluding Greater China and several Southeast and West Asian countries). In addition, under the Kelun-HBM Agreement, following the completion of this offering, we may elect, subject to certain conditions, to satisfy up to 50% of the remaining of each of our first seven development milestone payments, which is up to $73.75 million, payable under the Kelun-HBM Agreement by issuing our common shares, rather than in cash; provided that each of Kelun and HBM may not hold, in the aggregate, 20% or more of our outstanding share capital on a fully diluted basis as a result of such equity issuance. Any such issuance of common shares in satisfaction of milestone payments would dilute the ownership interests of our existing shareholders. Under the Qyuns Agreement, we may be required to pay Qyuns aggregate development milestone payments of up to $100 million for WIN027, aggregate sales milestone payments of up to $570 million upon achievement of specified annual net sales thresholds, and mid-single digit to high-single digit tiered royalties on net sales of WIN027 in our licensed worldwide territory (excluding Greater China).

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We may seek to grow our business through

through acquisitions or investments in new or complementary businesses, products or technologies, through the licensing of products or technologies from third parties or other strategic alliances. The failure to manage acquisitions, investments, licenses or other strategic alliances, or the failure to integrate them with our existing business, could have a material adverse effect on our operating results, dilute our shareholders' ownership, increase our debt or cause us to incur significant expense.

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To finance any acquisitions, investments or strategic alliances, we may choose to issue common shares as consideration, which could dilute the ownership of our shareholders. If the price of our common shares is low or volatile, we may be unable to consummate any acquisitions, investments or strategic alliances using our common shares as consideration. Additional funds may not be available on terms that are favorable to us, or at all.

Additional funds may not be available on terms that are favorable to us, or at all.

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The legislative and regulatory framework for

legislative and regulatory framework for the processing of personal data worldwide is rapidly evolving in a manner that is increasingly stringent and, globally, this legal and regulatory framework is likely to remain uncertain for the foreseeable future. In the United States, numerous federal, state and local laws and regulations, including federal health information privacy laws, state information security and data breach notification laws, federal consumer protection laws (e.g., Section 5 of the Federal Trade Commission Act), state consumer protection and privacy laws, and other similar laws (e.g., wiretapping and communications interception laws) govern the processing of sensitive data.

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Outside the United States, an increasing number of

of laws, regulations, and industry standards govern privacy, data security, and the transfer of personal data between jurisdictions. For example, the European Union's General Data Protection Regulation, or EU GDPR, the United Kingdom's General Data Protection Regulation, or UK GDPR (together with the EU GDPR, the GDPR), and the Swiss Federal Act on Data Protection impose strict requirements for collecting and processing personal data including relating to collecting and processing of sensitive data (referred to as special category data under GDPR), such as health data, ensuring there is a legal basis or condition to justify the processing of personal data, where required, requirements relating to obtaining consent of individuals, disclosures about how personal data is to be used, limitations on retention of information, limitations on the cross-border cross- border disclosure of personal data, implementing safeguards to protect the security and confidentiality of personal data, where required providing notification of data breaches, maintaining records of processing activities and documenting data protection impact assessments where there is high risk processing and taking certain measures when engaging third-party processors. Under GDPR, companies may face temporary or definitive bans on data processing and other corrective activities, fines of up to € 20 million under the EU GDPR (and 17.5 million GBP under the UK GDPR) or 4% of annual global turnover, whichever is greater, and private litigation related to processing of personal data brought by classes of data subjects or consumer protection organizations authorized at law to represent their interests. Additionally, in the European Union, the Network and Information Security Directive, or NIS2, regulates resilience and incident response capabilities of entities operating in a number of sectors, including the health sector. Non-compliance with NIS2 may, similar to non-compliance with other privacy or security laws, lead to adverse consequences, including a material adverse effect on our business, financial position and results of operations.

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Additionally, companies that transfer personal data across national borders are subject to increased scrutiny from regulators, individual litigants, and activist groups. For example, some European regulators have ordered certain companies to suspend or permanently cease certain transfers of personal data out of the EU for allegedly violating the GDPR's cross-border data transfer limitations.

In addition, we may be unable

In addition, we may be unable to transfer personal data from the PRC, the European Union / European Economic Area (EU 27 Member States, Norway, Iceland and Liechtenstein), or EEA, the United Kingdom, or UK, and other jurisdictions to the United States or other countries due to data localization requirements or restrictions on cross-border data flows. In particular, the European Union, the United Kingdom and Switzerland have significantly restricted the transfer of personal data to the United States and other countries whose privacy laws the European Commission, UK Secretary of State or Swiss Federal Council (as applicable) generally regard as inadequate. There are also restrictions on personal data exports from the PRC—under the PIPL, entities exporting personal data are required to meet certain conditions, including, to the extent applicable, satisfaction of the security assessments conducted by competent government authorities, signing and filing of standard contracts or obtaining certifications from qualified institutions (unless an exemption applies), and fulfillment of notice and consent requirements. Data qualifying as "important data" must also be localized in the PRC unless a security assessment is passed. Other jurisdictions may equally adopt or have already adopted similarly stringent data localization and cross-border data transfer laws. Although there are currently various mechanisms that may be used to transfer personal data from the EU/EEA, the United Kingdom and Switzerland to the United States in compliance with law, such as the EU standard contractual clauses, which are also recognized by Switzerland, the United Kingdom's International Data Transfer Agreement / Addendum, the EU-U.S. Data Privacy Framework, the UK extension thereto (which allows for transfers to relevant U.S.-based organizations who self-certify compliance and participate in the EU-U.S. Data Privacy Framework) and the Swiss-U.S. Data Privacy Framework, or Framework, these mechanisms are subject to legal challenges, and there is no assurance that we can satisfy or rely on these measures to lawfully transfer personal data to the United States. If there is no lawful manner for us to transfer personal data from the PRC, the EU/EEA, the United Kingdom, Switzerland, or other jurisdictions to the United States (or other countries), or if the requirements for a legally-compliant transfer are too onerous, we could face significant adverse consequences, including the interruption or degradation of our operations, the need to relocate part of or all of our business or data processing activities to other jurisdictions at significant expense, increased exposure to regulatory actions, substantial fines and penalties, the inability to transfer data and work with collaborators, vendors and other third parties, and injunctions against our processing or transferring of personal data necessary to operate our business. Additionally, companies that transfer personal data across national borders are subject to increased scrutiny from regulators, individual litigants, and activist groups. For example, some European regulators have ordered certain companies to suspend or permanently cease certain transfers of personal data out of the EU for allegedly violating the GDPR's cross-border data transfer limitations.

Additionally, the U.S. Department of Justice issued a rule entitled "Access to U.S. Sensitive Personal Data and Government-Related Data by Countries of Concern or Covered Persons," which places additional restriction restrictions on certain data transactions involving countries of concern (for example, the PRC, Russia and Iran) and covered persons (for example, individuals and entities who are designated as such by the U.S. Attorney General or considered "foreign persons" and are majority owned by, organized under the laws of, a primary resident in, an employee of, or a contractor of, a covered person or country of concern, as applicable) that may impact certain business activities such as vendor engagements, sale or sharing of data, employment of certain individuals and investor agreements. Violations of the rule could lead to significant civil and criminal fines and penalties. The rule applies regardless of whether data is anonymized, key-coded, pseudonymized, de-identified or encrypted, which presents particular challenges for companies like ours that operate in the clinical trial space and may impact our ability to engage in certain transactions or agreements with certain third parties in the future.

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Any of these outcomes could damage our reputation,

Risks Related to the Discovery and

Clinical testing is expensive, difficult to design and

Any of these outcomes could damage our reputation, result in regulatory investigations or enforcement actions as well as private litigation, and adversely impact our business.

Risks Related to the Discovery and Development of WIN378, WIN027 or Any Other Potential Future Product Candidates The regulatory approval processes of the FDA, the EMA, and the European Commission and other comparable foreign regulatory authorities are lengthy, time-consuming and inherently unpredictable, and if we are ultimately unable to obtain regulatory approval for WIN378, WIN027 or any other potential future product candidates, our business will be substantially harmed.

We are not permitted to commercialize, market, promote or sell any product candidate in the United States without obtaining regulatory approval from the FDA. Regulatory authorities outside of the United States impose similar requirements. The time required to obtain approval by the FDA, European Commission and other comparable foreign regulatory authorities is inherently unpredictable, but typically takes many years following the commencement of clinical trials and depends upon numerous factors, including substantial discretion of the regulatory authorities. In addition, approval policies, regulations, or the type and amount of clinical data necessary to gain approval may change during the course of a product candidate's clinical development and may vary among jurisdictions. For instance, jurisdictions outside of the United States, such as the European Union or Japan, may have different requirements for regulatory approval, which may require us to conduct additional clinical, non-clinical or chemistry, manufacturing and control studies. To date, we have not submitted a BLA to the FDA or similar drug approval submissions to comparable foreign regulatory authorities for any product candidate. We must complete additional preclinical nonclinical studies or clinical trials to demonstrate the safety and efficacy of WIN378, WIN027 or any other potential future product candidates in humans before we will be able to obtain these approvals.

Clinical testing is expensive, difficult to design and implement, can take many years to complete and is inherently uncertain as to outcome. The general approach for FDA approval of a new drug is dispositive data from two or more adequate and well-controlled clinical trials of the product candidate in the relevant patient population. The FDA, the EMA, the European Commission, or other comparable foreign regulatory authorities may disagree with us about whether a clinical trial is adequate and well-controlled or may request that we conduct additional clinical trials prior to regulatory approval. We cannot guarantee that any clinical trials will be conducted as planned or completed on schedule, if at all. In addition, there is no assurance that the doses, endpoints and trial designs that we intend to use for our planned clinical trials, including those that we have developed based on feedback from regulatory agencies or those that have been used for the approval of similar drugs, will be acceptable for future approvals. The clinical development of WIN378, WIN027 or any other potential future product candidates is also susceptible to the risk of failure inherent at any stage of development, including failure to demonstrate efficacy in a clinical trial or across a broad population of patients, the occurrence of adverse events that are severe or medically or commercially unacceptable, failure to comply with protocols or applicable regulatory requirements and determination by the FDA or any comparable foreign regulatory authority that a product candidate may not continue development or is not approvable. It is possible that even if WIN378, WIN027 or any other potential future product candidates have a beneficial effect, that effect will not be detected during clinical evaluation as a result of one or more of a variety of factors, including the size, duration, design, measurements, conduct or analysis of our clinical trials. Conversely, as a result of the same factors, our clinical trials may indicate an apparent positive effect of such product candidate that is greater than the actual positive effect, if any. Similarly, in our clinical trials we may fail to detect toxicity of, or intolerability caused by, such product candidate, or mistakenly believe that WIN378, WIN027 or any other potential future product candidates are toxic or not well tolerated when that is not in fact the case. Serious adverse events or other adverse events, as well as tolerability issues, could hinder or prevent market acceptance of the product candidate at issue.

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the FDA, the EMA or the European Commission, or other comparable foreign regulatory authorities may disagree with our interpretation of data from clinical trials or preclinical nonclinical studies;

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We have concentrated our research and development

concentrated our research and development efforts on WIN378, an ultra-long-acting anti-TSLP therapy that we believe is differentiated from currently approved treatments primarily through its potential for twice-yearly subcutaneous dosing, and WIN027, a long-acting anti-TSLP and anti-IL-13 therapy, which we believe could—if successful—offer meaningful efficacy advantages beyond what approved monospecific therapies have achieved, though this has not yet been demonstrated in pivotal clinical trials. WIN378 is a fully human anti-TSLP monoclonal antibody that targets the TSLP ligand and has been engineered with half-life extension to enable potential twice-yearly subcutaneous dosing—a dosing interval that, if supported by our planned pivotal studies and approved for such use, would be meaningfully less frequent than currently approved TSLP-targeting therapies. WIN027 is a long-acting bispecific antibody that simultaneously targets both TSLP and IL-13, an approach with no currently approved therapy and which has not been validated in pivotal clinical trials. Our future success depends in part on the advantages of WIN378's extended dosing interval being confirmed in our ongoing POLARIS Phase 2/3 asthma study and SIRIUS Phase 2 COPD study, and on WIN027's dual-targeting approach demonstrating meaningful clinical benefit beyond what monospecific alternatives have achieved. There can be no assurance that development problems we may experience in the future will not cause significant delays or result in unforeseen issues or unanticipated costs, or that any such development problems can be overcome.

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In addition, the clinical study

In addition, the clinical study requirements of the FDA, the EMA and the European Commission, and other regulatory authorities, and the criteria these regulators use to determine the safety and efficacy of a product candidate, are determined according to the type, complexity, novelty, and intended use and market of the potential product. While TSLP and IL-13 are clinically validated targets—tezepelumab, an approved anti-TSLP antibody for asthma, and dupilumab, an approved anti-IL-4R a antibody for asthma and COPD, have established regulatory precedents for biologic therapies in these indications—the regulatory approval pathway for WIN378 with its novel twice-yearly dosing profile and for WIN027 as a first-in-class bispecific simultaneously targeting TSLP and IL-13 may be more complex, more expensive, and take longer than for product candidates with more established dosing regimens or mechanisms of action. Prior approvals by the FDA, the EMA and the European Commission, and other regulatory authorities for existing biologic treatments for asthma and COPD, such as tezepelumab and dupilumab, as well as other pathways to approval, may not be indicative of what these regulators may require for approval of WIN378 or WIN027. More generally, approvals by any regulatory authority may not be indicative of what any other regulatory authority may require for approval or what such regulatory authorities may require for approval in connection with our product candidates.

WIN378 and/or WIN027 may also not perform successfully in clinical trials or may be associated with adverse events that distinguish it from previously approved therapies or those that may be approved in the future. Unexpected clinical outcomes could materially and adversely affect our business, financial condition, results of operations and growth prospects.

If our clinical trials fail to replicate positive results from earlier preclinical nonclinical studies or clinical trials conducted by us or third parties, we may be unable to successfully develop, obtain regulatory approval for or commercialize WIN378, WIN027 or any other potential future product candidates.

The results observed from preclinical nonclinical studies or early-stage clinical trials of WIN378, WIN027, or any other potential future product candidates may not necessarily be predictive of the results of later-stage clinical trials that we conduct. Similarly, positive results from such preclinical nonclinical studies or early-stage clinical trials may not be replicated in our subsequent clinical trials. For instance, results observed in the Phase 1 clinical trial for WIN378—including the extended half-life supporting twice-yearly subcutaneous dosing, a low rate of antidrug antibodies, and favorable safety and tolerability results up to the highest dose tested—may no treatment-related serious adverse events were observed—may not translate to similar safety or efficacy tolerability results in our ongoing POLARIS Phase 2/3 study in patients with asthma or our SIRIUS Phase 2 study in patients with COPD. Similarly, results observed in our ongoing Phase 1 clinical trial for WIN027 and planned future Phase 2 studies in atopic dermatitis and COPD may not be replicated in any subsequent clinical trials for that product candidate. Furthermore, WIN378, WIN027, or any other potential future product candidates may not be able to demonstrate similar activity or adverse event profiles to other product candidates or approved therapies that we believe may have comparable profiles. In addition, in our planned future clinical trials, we may utilize clinical trial designs or dosing regimens that have not been tested in prior clinical trials for these product candidates, including novel trial designs intended to evaluate the twice-yearly dosing interval of WIN378 or the dual blockade of TSLP and IL-13 by WIN027 in pivotal settings.

There can be no assurance that any of our clinical trials will ultimately be successful or support further clinical development of WIN378, WIN027, or any other potential future product candidates. There is a high failure rate for drugs proceeding through clinical trials. Many companies in the pharmaceutical and biotechnology industries have suffered significant setbacks in late-stage clinical trials after achieving positive results in early-stage development, and we cannot be certain that we will not face similar setbacks. These setbacks have been caused by, among other things, adverse safety or efficacy observations made in clinical trials. For example, we expect to report initial readouts from our POLARIS POLARIS-1 Phase 2/3 3 study evaluating WIN378 in patients with asthma in September 2026. the second half of 2028. These readouts may not be positive, may not meet the trial's pre-specified endpoints, or may not support the continuation of WIN378's development in asthma or other indications, any of which would have a material adverse effect on our business.

Moreover, preclinical nonclinical and clinical data are often susceptible to varying interpretations and analyses, and many companies that believed their product candidates performed satisfactorily in preclinical nonclinical studies and clinical trials nonetheless failed to obtain FDA, European Commission, or comparable foreign regulatory authority approval.

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We may experience delays in completing our clinical trials or preclinical nonclinical studies and initiating or completing additional clinical trials or preclinical nonclinical studies, including as a result of regulators not allowing or delaying clinical trials to proceed under an IND or similar foreign authorization, or not approving or delaying approval for any clinical trial grant or similar approval we need to initiate a clinical trial. We may also experience numerous unforeseen events during our clinical trials that could delay or prevent our ability to receive regulatory approval or commercialize WIN378, WIN027 or any other potential future product candidates we develop, including:

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committees of the institutions in which clinical trials are being conducted may suspend, limit or terminate a clinical trial, or data monitoring committees may recommend that we suspend or terminate a clinical trial, due to a number of factors, including failure to conduct the clinical trial in accordance with regulatory requirements or our clinical protocols, inspection of the clinical trial operations or trial site by the FDA, the competent authorities of individual EU Member States, or other comparable foreign regulatory authorities resulting in the imposition of a clinical hold, safety issues or adverse side effects, failure to demonstrate a benefit from using a drug, changes in governmental regulations or administrative actions or lack of adequate funding to continue the clinical trial. Negative or inconclusive results from our clinical trials or preclinical nonclinical studies could mandate repeated or additional clinical trials and, to the extent we choose to conduct clinical trials in other indications, could result in changes to or delays in clinical trials of WIN378, WIN027 or any other potential future product candidates in such other indications. We do not know whether any clinical trials that we conduct will demonstrate adequate safety, purity and potency, or efficacy to result in regulatory approval to market WIN378, WIN027 or any other potential future product candidates for the indications that we are pursuing. If favorable results are not observed in later-stage clinical trials, do not produce favorable results, our ability to obtain regulatory approval for WIN378, WIN027 or any other potential future product candidates will be adversely impacted.

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For planning purposes, we sometimes estimate the timing of the accomplishment of various scientific, clinical, regulatory and other product development objectives. These milestones may include our expectations regarding the commencement or completion of scientific studies and clinical trials, the submission of regulatory filings or commercialization objectives. From time to time, we have announced and may in the future publicly announce the expected timing of some of these milestones, such as the completion of an ongoing clinical trial, the initiation of other clinical programs, receipt of regulatory approval or a commercial launch of a product. The achievement of many of these milestones may be outside of our control. All of these milestones are based on a variety of assumptions which, if not realized as expected, may cause the timing of achievement of the milestones to vary considerably from our estimates, including:

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In addition, clinical investigators may serve as scientific advisors or consultants to us from time to time and may receive cash compensation in connection with such services. If these relationships and any related compensation result in perceived or actual conflicts of interest or the FDA concludes that the financial relationship may have affected the interpretation of the preclinical nonclinical study or clinical trial, the integrity of the data generated at the applicable preclinical nonclinical study or clinical trial site may be questioned and the utility of the preclinical nonclinical study or clinical trial itself may be jeopardized, which could result in the delay or rejection by the FDA. Any such delay or rejection could prevent us from commercializing our product candidates, if approved.

Our failure to successfully initiate and

Our failure to successfully initiate and complete clinical trials and to demonstrate the efficacy and safety necessary to obtain regulatory approval to market WIN378, WIN027 or any other potential future product candidates would also significantly harm our business. Our development costs will also increase if we experience delays in testing or regulatory approvals and we may be required to obtain additional funds to complete clinical trials. We cannot assure you that our clinical trials will begin as planned or be completed on schedule, if at all, or that we will not need to restructure or otherwise modify our trials after they have begun. Significant clinical trial delays also could shorten any periods during which we may have the exclusive right to commercialize WIN378, WIN027 or any other potential future product candidates or allow our competitors to bring products to market before we do and impair our ability to successfully commercialize WIN378, WIN027 or any other potential future product candidates, which may harm our business, financial condition, results of operations and growth prospects. In addition, many of the factors that cause, or lead to, delays of clinical trials may ultimately lead to the denial of regulatory approval of WIN378, WIN027 or any other potential future product candidates.

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Interim, initial, top-line and preliminary data from our clinical trials that we announce or publish from time to time may change as more patient data become becomes available and are subject to audit and verification procedures that could result in material changes in the final data. From time to time, we publicly disclose preliminary or top-line data from our preclinical nonclinical studies and clinical trials, which are based on preliminary analyses of then-available data, and the results and related findings and conclusions are subject to change following a more comprehensive review of the data related to the particular preclinical nonclinical study or clinical trial. We also make assumptions, estimations, calculations and conclusions as part of our analyses of data, and we may not have received or had the opportunity to fully and carefully evaluate all data. As a result, the top-line or preliminary results that we report may differ from future results of the same studies or trials, or different conclusions or considerations may qualify such results, once additional data have been received and fully evaluated. Top-line data also remain subject to audit and verification procedures that may result in the final data being materially different from the preliminary data we previously published. As a result, top-line data should be viewed with caution until the final data are available. From time to time, we may also disclose interim data from our preclinical nonclinical studies and clinical trials. Interim data from clinical trials that we may complete are subject to the risk that one or more of the clinical outcomes may materially change as participants participant enrollment continues and more participants' data become available or as participants from our clinical trials continue other treatments for their disease. Adverse differences between interim data and final data could significantly harm our business prospects. Further, others, including regulatory agencies, may not accept or agree with our assumptions, estimates, calculations, conclusions or analyses or may interpret or weigh the importance of data differently, which could impact the value of the particular program, the approvability or commercialization of the particular product candidate and could adversely affect the success of our business. In addition, the information we choose to publicly disclose regarding a particular study or clinical trial is based on what is typically extensive information, and you or others may not agree with what we determine is material or otherwise appropriate information to include in our disclosure. If the interim, top-line or preliminary data that we report differ from actual results, or if others, including regulatory authorities, disagree with the conclusions reached, our ability to obtain approval for, and commercialize, WIN378, WIN027 or any other potential future product candidates may be harmed, which could harm our business, financial condition, results of operations and growth prospects. Further, disclosure of interim, top-line or preliminary data by us or by our competitors could result in volatility in the price of our common shares after this offering. Furthermore, if we fail to replicate the positive results from our preclinical nonclinical studies or clinical trials in our future clinical trials, we may be unable to successfully develop, obtain regulatory approval for and commercialize WIN378, WIN027 or any other potential future product candidates.

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If we are unable to enroll a sufficient number

If we are unable to enroll a sufficient number of patients for our clinical trials, it would result in significant delays or might require us to abandon one or more clinical trials or our development efforts altogether. Delays in patient enrollment may result in increased costs, affect the timing or outcome of the planned clinical trials, product candidate development and approval process and jeopardize our ability to seek and obtain the regulatory approval required to commence product sales and generate revenue, which could prevent completion of these trials, adversely affect our ability to advance the development of WIN378, WIN027 or any other potential future product candidates, cause our value to decline and limit our ability to obtain additional financing if needed.

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Undesirable side effects caused by WIN378, WIN027 or any other potential future product candidates could cause us or regulatory authorities to interrupt, delay or halt clinical trials and could result in a more restrictive label or the delay or denial of regulatory approval by the FDA, European Commission, or other comparable foreign regulatory authorities. We may also observe additional safety or tolerability issues with WIN378, WIN027 or any other potential future product candidates in ongoing or future clinical trials. Although WIN378 demonstrated was generally favorable safety and tolerability results well-tolerated in a Phase 1 single ascending dose study and a pre-planned interim analysis of the Phase 2 portion of POLARIS-2 in healthy volunteers, including no treatment-related serious adverse events, above Grade 2, a withdrawals or discontinuations observed, and low rate rates of anti-drug antibodies (approximately 4%) and no injection site reactions and antidrug antibodies, this data was generated in a small, healthy volunteer population and may not be predictive of the safety profile in larger patient populations with asthma or COPD. WIN027 is currently being evaluated in a Phase 1 clinical trial in healthy volunteers, with initial results expected in the third quarter of 2026, and has no reported clinical safety based on blinded interim data, we have observed a 62-day half-life, low immunogenicity and low rate of injection site reactions.

Many compounds that initially showed promise in clinical or earlier-stage testing are later found to cause undesirable or unexpected side effects that prevented further development of the compound. Results of ongoing or future clinical trials of WIN378, WIN027 or any other potential future product candidates could reveal a high and unacceptable severity and prevalence of side effects or unexpected characteristics, despite a favorable tolerability profile no treatment-related serious adverse events were observed in earlier-stage testing. In addition, although we believe that WIN378's mechanism of action and broader epitope binding profile may differentiate it from other anti-TSLP therapies, and WIN027's simultaneous inhibition of both TSLP and IL-13 may differentiate it from monospecific therapies, adverse events observed in clinical studies or postmarket use of anti-TSLP therapies, anti-IL-13 therapies, or other anti-TSLP x IL-13 bispecific programs in clinical development may also be observed with WIN378 and WIN027, which could impact our ability to recruit patients to our clinical trials and our clinical development strategy.

If unacceptable side

If unacceptable side effects arise in the development of WIN378, WIN027 or any other potential future product candidates, we, the FDA, competent authorities of individual EU Member States, or other comparable foreign regulatory authorities, the IRBs, or independent ethics committees at the institutions in which our trials are conducted, could suspend, limit or terminate our clinical trials, or the independent safety monitoring committee could recommend that we suspend, limit or terminate our trials, or the FDA, competent authorities of individual EU Member States or other comparable foreign regulatory authorities could order us to cease clinical trials, or the FDA, the European Commission, or other comparable foreign regulatory authorities could deny approval of WIN378, WIN027 or any other potential future product candidates for any or all targeted indications. Treatment-emergent side effects that are deemed to be drug-related could delay recruitment of clinical trial subjects or may cause subjects that enroll in our clinical trials to discontinue participation in our clinical trials. In addition, these side effects may not be appropriately recognized or managed by the treating medical staff. We may need to train medical personnel using WIN378, WIN027 or any other potential future product candidates to understand the side effect profiles for our clinical trials and upon any commercialization of WIN378, WIN027 or any other potential future product candidates. Inadequate training in recognizing or managing the potential side effects of WIN378, WIN027 or any other potential future product candidates could result in harm to patients that are administered WIN378, WIN027 or any other potential future product candidates. Any of these occurrences may adversely affect our business, financial condition, results of operations and growth prospects significantly.

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Expansion into new indications will require additional, time-consuming development efforts prior to commercial sale, including preclinical nonclinical studies, clinical trials and approval by the FDA, the European Commission, and comparable foreign regulatory authorities. All product candidates are prone to the risks of failure that are inherent in pharmaceutical product development, including the possibility that the product candidate will not be shown to be sufficiently safe, pure and potent, or effective for approval by regulatory authorities. In addition, we cannot assure you that any such products that are approved will be manufactured or produced economically, successfully commercialized or widely accepted in the marketplace or be more effective than other commercially available alternatives.

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We have never commercialized a product, and even if WIN378, WIN027 or any other potential future product candidate is approved by the appropriate regulatory authorities for marketing and sale, such product candidate may nonetheless fail to achieve sufficient market acceptance by physicians, patients, third-party payors and others in the medical community. Many of the indications for WIN378 and WIN027 have well-established standards of care that physicians, patients and payors are familiar with. Even if WIN378, WIN027 or any other potential future product candidates are successful in registrational clinical trials, such product candidate may not be successful in displacing these current standards of care if we are unable to demonstrate superior efficacy, safety, ease of administration and/or cost-effectiveness. For example, physicians may be reluctant to start biologic-na ve patients on a new medication or take their patients off their current medications and switch their treatment regimen to WIN378, WIN027 or any other potential future product candidates. Further, patients often acclimate to the treatment regimen that they are currently taking and do not want to switch unless their physicians recommend switching products or they are required to switch due to lack of coverage and adequate reimbursement. Even if we are able to demonstrate WIN378's, WIN027's or any other potential future product candidates' safety, purity and potency, or efficacy to the FDA, the European Commission, and other regulators, safety or efficacy concerns in the medical community may hinder market acceptance.

Further, patients often acclimate to the treatment regimen that they are currently taking and do not want to switch unless their physicians recommend switching products or they are required to switch due to lack of coverage and adequate reimbursement. Even if we are able to demonstrate WIN378's, WIN027's or any other potential future product candidates' safety, purity and potency, or efficacy to the FDA, the European Commission, and other regulators, safety or efficacy concerns in the medical community may hinder market acceptance.

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In most cases, we do not currently plan to

Our competitors may have

clinical and commercial landscapes for the treatment of inflammatory diseases are highly competitive and subject to rapid and significant technological change. We face competition with respect to our indications for WIN378, WIN027 and will face competition with respect to any other drug candidates that we may seek to develop or commercialize in the future, from major pharmaceutical companies, specialty pharmaceutical companies and biotechnology companies worldwide. There are a number of large pharmaceutical and biotechnology companies, such as Amgen Inc., Apogee Therapeutics, Inc. (pending acquisition (acquired by AbbVie Inc.), AstraZeneca plc, Belenos Biosciences Inc., Generate Biomedicines, Inc., GSK plc, Johnson & Johnson, KeyMed Biosciences Inc., Eli Lilly and Company, Pfizer Inc., Sanofi S.A., and Upstream Bio, Inc. that currently market and sell drugs or are pursuing the development of drug candidates for the treatment of the indications that we are pursuing. Potential competitors also include academic institutions, government agencies and other public and private research organizations that conduct research, seek patent protection and establish collaborative arrangements for research, development, manufacturing and commercialization.

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and 172 more changes in the filing

Use of proceeds 9 changes

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Approximately $ million to fund the completion of our ongoing

Approximately $ million to fund our bispecific programs; and

Approximately $ million to fund (i) the completion of our ongoing POLARIS-1 Phase 2/3 trial and a confirmatory POLARIS-2 Phase 3 trial of WIN378 in asthma; (ii) the completion of our ongoing SIRIUS Phase 2 trial of WIN378 in COPD; and (iii) related research and development activities, including clinical development, regulatory affairs, quality, research, translational sciences, clinical supply, and drug substance and drug product manufacturing;

Approximately $ million to fund the completion of (i) our planned global Phase 2b trial of WIN027 in COPD; (ii) our planned global Phase 2 trial of WIN027 in atopic dermatitis; and (iii) related research and development activities, including clinical development, regulatory affairs, quality, research, translational sciences, clinical supply, and drug substance and drug product manufacturing;

Approximately $ million to fund the advancement of our bispecific programs through the completion of IND-enabling studies; and ∎ The remainder for working capital and general corporate purposes, including personnel costs, facilities, and other operational expenses.

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Due to inherent uncertainties in the development of our product candidates, the amount and timing of our actual expenditures may vary significantly depending on many factors, including the progress of our research and development activities, timing of patient enrollment in our studies, evolving regulatory requirements, timing and success of preclinical nonclinical studies, ongoing and future clinical trials, timing of any future regulatory submissions, any partnerships or alliances we may enter into with third parties, unforeseen cash needs and other factors described in the "Risk Factors" included elsewhere in this prospectus.

Based on our current plans and business

Based on our current plans and business conditions, we believe our existing cash, cash equivalents and marketable securities, together with the net proceeds from this offering, will be sufficient to enable us to fund our operating expenses and capital expenditure requirements through . This determination is based on certain assumptions that may prove incorrect and we may use our available capital resources sooner than expected. We do not have any committed external sources of funds as of the date of this prospectus. In the future, we may meet any future cash needs through the sale of additional equity securities, raising debt financing, obtaining working capital lines of credit, interest income earned on our interest-bearing cash deposits, or a combination of these sources.

Pending our use of the net proceeds from this offering, we intend to invest the net proceeds in a variety of capital preservation instruments, including investment-grade corporate bonds, fixed-income instruments, money market funds and interest-bearing deposits held at reputable institutions. We cannot guarantee that the net proceeds invested will yield a favorable return. Our management retains broad discretion in the application of the net proceeds received from this offering and investors will rely on the judgement of our management regarding the application of our net proceeds.

Dividend policy 1 change

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Distributable reserves are generally booked either as voluntary retained earnings ( freiwillige Gewinnreserven ), as statutory retained earnings ( gesetzliche Gewinnreserve ), or as statutory capital reserves ( gesetzliche Kapitalreserve ), including as reserves from capital contributions ( Kapitaleinlagereserven ). In accordance with the requirements of Swiss law, we are required to retain at least 5% of our annual net income as statutory retained earnings ( gesetzliche Gewinnreserve ) for so long as these reserves, together with the statutory capital reserves ( gesetzliche Kapitalreserve ), amount to less than 20% of our paid-in nominal share capital. If there is a loss carried forward, such loss must be eliminated by way of set-off with the profit, before the latter may be allocated to statutory retained earnings ( gesetzliche Gewinnreserve ). Furthermore, in order for us to pay dividends we can make distributions to our shareholders out of reserves from capital contributions ( Reserven aus Kapitaleinlagen ) such reserves have if and to be eligible for classification as the extent (i) we have sufficient freely distributable reserves under Swiss law, which requires that equity and (ii) the statutory capital reserves ( gesetzliche Kapitalreserve ) together with and statutory retained earnings ( gesetzliche Gewinnreserve ), taken together and after deduction of losses, if any, exceeds exceed 20% of our paid in nominal share capital. Distributions out of issued share capital, which is the aggregate nominal value of a corporation's issued shares, may be made only by way of a share capital reduction. See the section of this prospectus titled "Description of Share Capital and Articles of Association—Dividends and Other Distributions."

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Capitalization 11 changes

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on a pro forma basis, giving effect to (i) the Preferred Share Conversion, and as if the preferred shares had been converted to common shares as of June 30, 2026, (ii) the Series B Warrant Settlement, as if the Series B Warrants had been exercised as of June 30, 2026, and (iii) the filing and effectiveness of our amended and restated articles of association, which will occur immediately prior to the completion of this offering; and on a pro forma as adjusted basis, giving effect to (i) the pro forma adjustments set forth above and (ii) the issuance and sale of common shares in this offering at the assumed initial public offering price of $ per share, which is the midpoint of the estimated offering price range listed on the cover page of this prospectus, after deducting estimated underwriting discounts and commissions of $ and estimated offering expenses payable by us of $ .

The pro forma as adjusted information below is for illustrative purposes only, and our capitalization following the completion of this initial public offering will be adjusted based on the actual initial public offering price and other terms of this offering determined at pricing.

The following table should be read together

The following table should be read together with "Management's Discussion and Analysis of Financial Condition and Results of Operations," "Use of Proceeds" and the unaudited condensed consolidated interim financial statements and related notes included elsewhere in this prospectus.

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Preferred shares (Series A preferred shares, Series A junior preferred shares and Series B preferred shares), par value CHF 0.01 per share; 53,429,037 shares issued and outstanding, actual; shares issued and outstanding, pro forma and shares issued and outstanding, pro forma as adjusted Common shares, par value CHF 0.01 per share; 15,542,386 shares issued, actual; shares issued, pro forma and shares issued, pro forma as adjusted Share capital Treasury shares (Common shares, par value CHF 0.01 per share; 50,700 shares) (1 ) Reserves 358,087 Accumulated losses (93,195 ) Total shareholders' equity $ 265,724 $ $ Total capitalization $ 265,724 $ $ (1) CHF amounts contained in this table have been translated into U.S. dollars at the rate of CHF1.00 to $ , solely for the convenience of the reader, which was the noon buying rate of the Federal Reserve Bank of New York on June 30, 2026.

Preferred shares (Series A preferred shares, Series A junior preferred shares and Series B preferred shares), par value CHF 0.01 per share; 53,429,037 preferred shares issued and outstanding, actual; no preferred shares issued and outstanding, pro forma and no preferred shares issued and outstanding, pro forma as adjusted (1) Common shares, par value CHF 0.01 per share; 15,542,386 shares issued, actual; common shares issued, pro forma and common shares issued, pro forma as adjusted (1) Share capital Treasury shares (Common shares, par value CHF 0.01 per share; 50,700 shares) (1 ) Reserves 358,087 Accumulated losses (93,195 ) Total equity $ 265,724 $ $ Total capitalization $ 265,724 $ $ (1) CHF amounts contained in this table have been translated into U.S. dollars at the rate of CHF1.00 to $1.2372, solely for the convenience of the reader, which was the noon buying rate of the Federal Reserve Bank of New (2) Each $1.00 increase or decrease, as applicable, in this assumed initial public offering price of $ per share, which is the midpoint of the estimated offering price range listed on the cover page of this prospectus, would increase or decrease, as applicable, the pro forma as adjusted amount of each cash and cash equivalents, and marketable securities, total shareholders' equity and total capitalization by $ million, assuming that the number of shares offered by us in this initial public offering remains the same, and after deducting estimated underwriting discounts and commissions and estimated offering expenses payable by us. Similarly, each increase or decrease, as applicable, of 1.0 million common shares offered by us at the assumed initial public offering price per share of $ , the midpoint of the estimated offering price range listed on the cover page of this prospectus would increase or decrease, as applicable, the pro forma as adjusted amount of each of cash and cash equivalents, and marketable securities, total shareholders' equity and total capitalization by $ million, after deducting estimated underwriting discounts and commissions and estimated offering expenses payable by us.

The number of common shares to be outstanding after the offering is based on 15,491,686 common shares (including 6,797,703 restricted shares subject to repurchase rights based on continued service requirements and 1,133,155 restricted shares subject to repurchase rights that lapse if this offering closes), 31,897,927 Series A preferred shares, 5,582,139 Series A junior preferred shares, and 15,948,971 Series B preferred shares outstanding as of June 30, 2026 and 397,495 Series B Warrants, and excludes:

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50,700 common shares we hold in treasury; and

397,495 common shares reserved for future issuance as of June 30, 2026 related to the warrants issued in connection with our Series B financing, all of which will be issued prior to the completion of our initial public offering.

common shares that are reserved for future issuance issuable upon exercise or settlement of awards pursuant to our 2026 Equity Incentive Plan, or the 2026 Plan, as more fully described in the section titled "Management—Equity Incentive Plans";

common shares reserved for issuance issuable under our 2026 Employee Share Purchase Plan, or the ESPP; and ∎ 50,700 common shares we hold in treasury.

Dilution 13 changes

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Dilution per share to new investors is determined by

Our pro forma net tangible book value as

value as of June 30, 2026 was $ million or $ per share. Pro forma net tangible book value per share represents the amount of our total tangible assets (net of deferred offering costs of $ million) less our total liabilities and divided by the number of our common shares outstanding as of June 30, 2026, after giving effect to the conversion of all outstanding Preferred shares into 53,429,037 number of common shares immediately prior to Share Conversion and the completion of this offering. Series B Warrant Settlement. Pro forma net tangible book value per share represents our pro forma net tangible book value divided by the total number of common shares outstanding as of June 30, 2026, after giving effect to the pro forma adjustments described above.

After giving further effect to the sale of common shares that we are offering at the assumed initial public offering price of $ per share, which is the midpoint of the estimated offering range set forth on the cover page of this prospectus, and after deducting estimated underwriting discounts and commissions of $ and estimated offering expenses payable by us of $ (assuming the underwriters do not exercise their option to purchase additional common shares), our pro forma as adjusted net tangible book value as of June 30, 2026 would have been $ million or $ per share. This amount represents an immediate increase in our pro forma net tangible book value as of $ per share to our existing shareholders and an immediate dilution in pro forma as adjusted net tangible book value of $ per share to new investors purchasing our common shares in this offering.

Dilution per share to new investors is determined by subtracting pro forma as adjusted net tangible book value per share after this offering from the initial public offering price per share paid by new investors. The following table illustrates this dilution (without giving effect to any potential exercise by the underwriters of their option to purchase additional common shares):

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Pro forma increase decrease in net tangible book value per share as of June 30, 2026 attributable to the pro forma adjustment described above Pro forma net tangible book value per share as of June 30, 2026 Increase in pro forma net tangible book value per share attributable to new investors participating in this initial public offering $ Pro forma as adjusted net tangible book value per share after this initial public offering Dilution per share to new investors in this initial public offering $ The dilution information discussed above is for illustrative purposes only and may change based on our actual initial public offering price and other terms of this offering.

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The number of common shares to be outstanding after the offering is based on 15,491,686 common shares (including 6,797,703 restricted shares subject to repurchase rights based on continued service requirements and 1,133,155 restricted shares subject to repurchase rights that lapse if this offering closes), 31,897,927 Series A preferred shares, 5,582,139 Series A junior preferred shares, and 15,948,971 Series B preferred shares outstanding as of June 30, 2026 and 397,495 Series B Warrants, and excludes:

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397,495 common shares reserved for future issuance as of June 30, 2026 related to the warrants issued in connection with our Series B financing, all of which will be issued prior to the completion of our initial public offering.

To the extent any outstanding

common shares that are reserved for future issuance issuable upon exercise or settlement of awards pursuant to our 2026 Plan, as more fully described in the section titled "Management—Equity Incentive Plans";

common shares reserved for issuance issuable under our ESPP; and

50,700 common shares we hold in treasury. and

To the extent any outstanding options or warrants are exercised, new options or other equity awards are issued under our equity incentive plans, or we issue additional equity or we issue convertible debt securities in the future, there will be further dilution to new investors.

MD&A 99 changes

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WIN378 is currently being

During the year ended

being evaluated in POLARIS-1, a Phase 2/3 study in severe uncontrolled asthma. Study start-up activities were initiated in September 2026 for a second Phase 3 asthma study (POLARIS-2), which is planned and to begin patient recruitment in the first half of 2027. A Phase 2 study of WIN378 in COPD, SIRIUS, was initiated in June 2026. We expect that the next data readout for WIN378 will be a Phase 2 interim analysis in the second half of 2026.

WIN027 is currently in a Phase 1 healthy volunteer study with INDs open in the United States, Australia and the PRC, assessing safety and pharmacokinetics. We plan to initiate initiated study start-up activities in September 2026 for our two global Phase 2 studies in the first half of 2027—a studies—a global Phase 2 study in COPD fully powered on the registrational endpoint of exacerbation rate ratio and a second global Phase 2 study in atopic dermatitis, which are planned to begin patient recruitment in the first half of 2027. We expect that the next data readout for WIN027 will be the full Phase 1 results in the first half of 2027.

Since our inception, we have incurred significant net operating losses and negative cash flows. Since inception, we have devoted the majority of our resources to organizing and staffing our company, business planning, raising capital, establishing licensing, developing our product candidates, conducting research studies and trials (preclinical (nonclinical and clinical), establishing relationships with third parties for research and manufacture of products for use in our trials as well as general and administrative activities to support these operations.

During the year ended December 31, 2025, we generated a net loss of $48.3 million. For the six months ended June 30, 2026, we have generated a net loss of $42.6 million, and a net loss of $22.8 million in the six months ended June 30, 2025. We expect to continue to incur significant losses and that our expenses and operating losses will continue to increase for the foreseeable future if and as we:

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begin additional preclinical, nonclinical, clinical or other studies for our product candidates (current and future), including pursuing additional license and collaboration agreements and new partnerships;

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To date, we have not generated any revenue and we have raised capital primarily through our Series A and Series B financing rounds, through the issuance of our Series A preferred shares and the issuance of our Series B preferred shares (together with Series A preferred shares, Preferred Shares). As of the date of this prospectus, Since inception and up to June 30, 2026, we have received total gross proceeds of $310.0 million from our financing rounds. As needed, we will seek additional funding through public or private equity or debt financing. We may not be able to obtain funding on acceptable terms, or at all. The terms of future financing may adversely affect the holdings or rights of our current shareholders.

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Series A and Series B Financing

On January 10, 2025, we completed a

January 10, 2025, we launched a $200.0 million Series A financing round, which was paid in two tranches. On January 23, 2025, we completed the first tranche for $75.0 million. In connection with the closing of the first tranche, we issued 11,961,724 Series A preferred shares and 1,212,120 common shares at a price of $6.27 and $0.01 per share, respectively. On July 11, 2025, we completed the second tranche for $125.0 million. In connection with the closing of the second tranche, we issued 19,936,203 Series A Preferred Shares at a price of $6.27 per share.

On April 17, 2026, we completed launched a $165.0 million Series B financing round, which will be paid was payable in two tranches. On May 12, 2026, we completed the first tranche for $110.0 million. In connection with the closing of the first tranche, we issued 15,948,971 Series B preferred shares at a price of $6.897 per share. Additionally, on May 12, 2026, we entered into warrant agreements with certain of the investors who participated in our Series B financing round. Each warrant we granted allows the warrant holder to purchase one common share of Windward Bio Group AG. Each warrant has an exercise price of CHF 0.01.

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We may be required to make additional payments to Kelun and HBM based on the occurrence or non-occurrence of future events, including development milestones of up to $330.0 $320.0 million for WIN378 (excluding the total $10.0 million milestone payments as described below), as well as sales-related milestones of up to $600.0 million. Additionally, we may be required to pay tiered royalties through six tiers, ranging from low single digits to low double-digits (a spread of not more than 5 percentage points) on net sales of WIN378 products, to Kelun and HBM.

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On June 9, 2026, we achieved the second

On June 9, 2026, we achieved the second development milestone associated with the WIN378 License, which required us to make a payment to Kelun and HBM, in total, of $5.0 million. The second development milestone payment of $5.0 million was paid in July 2026.

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Factors Affecting the

Comparability of Results of Operations

As consideration for the WIN027 License, we made payments of cash and equity interests to Qyuns and its affiliates, totaling $30.0 million. In the first quarter of 2026, $15.0 million was paid in cash, and the remaining $15.0 million was paid in our equity interest in the first quarter of 2026. valued at $15.0 million.

We may be required to make additional payments to

make additional payments to Qyuns based on the occurrence or non-occurrence of future events, including development milestones of up to $100.0 million, as well as sales-related milestones of up to $570.0 million. Additionally, we may be required to pay mid-single digit to high-single digit tiered royalties to Qyuns.

Our Factors Affecting the Comparability of Results of Operations business was incorporated on July 5, 2024 and as such, financial conditions and results of operation for the period from July 5, 2024 to December 31, 2024, or the 2024 period, does not represent an entire twelve-month fiscal year. As such, the year ended December 31, 2025 and the 2024 period are not directly comparable. At that the time of our inception, we were in the early stages of organizational activity and the nature of our expenses incurred differed from the expenses incurred more recently in the normal course of our business.

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To date, we have not generated any revenue from product

To date, we have not generated any revenue from product sales or services, and we do not expect to generate any revenue from the sale of products in the near future, if ever. If our development efforts for WIN378 or other product candidates are successful and result in regulatory approval, we may generate revenues in the future from product sales, payments from existing or potential future collaboration or license agreements with third parties, or any combination thereof.

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We expect our research and development expenses to increase for the foreseeable future as we work to advance the development of our product candidates through ongoing preclinical nonclinical studies and clinical trials as well as the development of any potential future product candidates we may acquire.

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estimate or know the nature, timing, or estimated costs of the efforts that will be necessary to complete the development of our product candidates. Currently, the Company does not track research and development expenses by program or product candidate. This is because our current activities remain in the discovery phase, where resources, personnel and external costs are shared across multiple research efforts and are not yet attributable to specific programs or product candidates in a systematic manner. We manage our research and development efforts dynamically, taking into account activities needed to support, expand and develop our product candidates. These activities include product formulation, preclinical nonclinical testing, clinical studies, data analysis, pharmacovigilance and regulatory submissions. As our development programs transition into the preclinical nonclinical stage and final product candidates are selected, we will begin tracking research and development expenses by product candidate.

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general and administrative expenses are primarily related to operating expenses such as insurance costs, travel expenses and facility expenses not otherwise included in research and development expenses, , as well as expenses of external advisors, including professional fees for legal, accounting, audit, and tax services. These expenses also include salaries and benefits for our general and administrative personnel, including share-based compensation for the personnel in our executive, finance, accounting, legal, human resources, business development, information technology and other administrative areas. Depreciation expense is recognized on our assets used in supporting our general and administrative functions.

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Payroll expenses and share-based

Depreciation expense increased by $0.1 million in the year ended December 31, 2025, compared to the period from July 5, 2024 to December 31, 2024.

Service and materials expenses increased by $23.4 million in the year ended December 31, 2025 compared to the period from July 5, 2024 to December 31, 2024, which was primarily driven by the initiation of our POLARIS-1 Phase 2/3 asthma study for WIN378 in asthma and related manufacturing activities.

Payroll expenses and share-based compensation in aggregate increased by $9.0 million in the year ended December 31, 2025 compared to the period from July 5, 2024 to December 31, 2024. This increase was primarily driven by the hiring of our first employees who focus on research and development activities, as we built out our research and development capabilities as well as the establishment of our equity incentive plans for research and development employees to allow them to participate in our equity.

Depreciation expense

increased by $0.1 million in the year ended December 31, 2025, compared to the period from July 5, 2024 to December 31, 2024. This increase was primarily driven by the acquisition of additional assets required to carry out our research and development activities, including equipment used in clinical trials.

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Operating expenses were $6.8 million for the year ended December 31, 2025, compared to $1.1 million for the period from July 5, 2024 to December 31, 2024. The $5.7 million increase was primarily driven by an increase in professional fees for legal accounting, audit, valuation and tax services. Spending on information technology services. Spending on accounting, audit, valuation, tax, software and hardware also increased.

Payroll expenses and share-based compensation in aggregate increased by $12.3 million in the year ended December 31, 2025, compared to the period from July 5, 2024 to December 31, 2024. This increase was primarily driven by an increase in headcount as we continue continued to hire and build out our administrative functions. Additionally, we established equity incentive plans to allow these employees to participate in our equity.

Depreciation increased by $0.1 million in the year ended December 31, 2025, compared to the 2024 period. This increase was primarily driven by the acquisition of assets to build out our administrative functions. We did not have any such assets in the 2024 period.

This increase was primarily driven by the acquisition of assets to build out our administrative functions. We did not have any such assets in the 2024 period.

Financial income, financial expenses and foreign exchange differences, net Our financial income was $3.6 million during the year ended December 31, 2025, compared to nil for the period from July 5, 2024 to December 31, 2024. The increase was driven by fair value gains on financial assets measured at fair value through profit or loss and interest income earned on cash equivalents and marketable securities, both of which arose following the receipt investment of the proceeds from our Series A financing round.

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Personnel expenses and share-based compensation in aggregate increased by $3.9 million in the six months ended June 30, 2026 compared to the six months ended June 30, 2025. This increase was primarily driven by additional hiring and increasing headcount needed to build our team to support our research and development activities and these new employees' participation in our equity plans.

Depreciation increased by $0.2 million in the six months ended

Depreciation increased by $0.2 million in the six months ended June 30, 2026 compared to the six months ended June 30, 2025. The increase was primarily driven by the acquisition of additional assets required to carry out our research and development activities, including equipment used in clinical trials.

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General and administrative expenses were $14.5 million for the six months ended June 30, 2026 compared to $10.0 million for the six months ended June 30, 2025. The increase was primarily driven by additional spending on external services such as legal, accounting, and other professional services, and an increase in stock-based share-based compensation.

Personnel expenses and share-based compensation in aggregate increased by $2.5 million in the six months ended June 30, 2026 compared to the six months ended June 30, 2025. This increase was primarily driven by an increase in headcount as we continue continued to hire and build out our administrative functions, as well as offering participation in our equity plan to these new employees.

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Our income tax was insignificant during the six months

Financial income, financial expense and foreign exchange differences, net Our financial income was $2.2 million during the six months ended June 30, 2026, compared to $0.7 million during the six months ended June 30, 2025. This increase was driven by fair value gains on financial assets measured at fair value through profit or loss and interest income earned on cash equivalents and marketable securities driven by the receipt investment of the proceeds from the first tranche of our Series B financing round.

Our financial expense and foreign exchange differences, net were insignificant during the six months ended June 30, 2026 and 2025.

Our income taxes were insignificant

during the six months ended June 30, 2026 and 2025.

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Since our inception, we have incurred significant operating losses and negative cash flows from our operations. operating activities. We have not commercialized any of our product candidates and we do not expect to be able to generate any revenue from product sales for the next several years, if ever. Our operations have been primarily financed through the issuance of our Preferred Shares. As of the date of this prospectus, Since inception and up to June 30, 2026, we have received gross proceeds of $310.0 million from the issuance of our Preferred Shares. As of June 30, 2026, we had cash, cash equivalents and marketable securities of $207.3 million.

The following table provides information regarding our cash flows for the periods presented (in thousands):

cash flows for the periods presented (in thousands):

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During the year ended December 31, 2025, net cash

cash used in operating activities was $33.3 million, resulting primarily from the net loss incurred during the year ended December 31, 2025. The net loss in this period was driven by the increases in expense associated with research and development activities, including additional service and materials expenses driven by the initiation of our POLARIS-1 Phase 2/3 asthma study for WIN378. Net cash from changes in operating assets and liabilities was primarily driven by the timing of our payments of our trade payables, which are generally settled within 60 days. These outflows were partially offset by interest received of $1.8 million.

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During the six months ended June 30, 2025,

During the six months ended June 30, 2025, operating activities used $9.7 million of cash, resulting primarily from our net loss incurred during our operations in the six months ended June 30, 2025. Net cash from changes in operating assets and liabilities was primarily driven by timing of our payment of trade payables and recognition of accrued expenses primarily related to our CRO and CDMO relations.

Net cash used in operating activities for the

Net cash used in operating activities for the six months ended June 30, 2026 increased by $16.2 million compared to net cash used in operating activities for the six months ended June 30, 2025. This increase was driven by an increase in net loss recognized of $19.9 million. These cash outflows were partially offset by an increase in interest received of $1.7 million in the six months ended June 30, 2026 compared to the six months ended June 30, 2025.

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During the six months ended June 30,

During the year ended December 31, 2025, net

During the year ended December 31, 2025, net cash used in investing activities was $144.2 million, resulting primarily from outflows for the purchase of financial instruments assets of $194.2 million and $25.0 million of cash payments to Kelun and HBM for our WIN378 License, which includes an upfront payment of $20.0 million to Kelun and HBM and the payment of our first development-related milestone of $5.0 million. These outflows were partially offset by cash inflows from proceeds received from our financial assets.

During the 2024 period, cash flows provided by investing activities were not significant as our operations began in January 2025.

During the six months ended June 30, 2026, investing activities used $83.3 million of cash, driven primarily by outflows from the purchase of additional financial assets and the payment of cash to Qyuns for our WIN027 License. These outflows were partially offset by cash inflows from proceeds received from our financial assets.

During the six months ended June 30, 2025, investing activities used $51.3 million of cash, driven primarily by outflows from the purchase of financial instruments assets and cash payments to HBM and Kelun from our WIN378 License. These outflows were partially offset by cash inflows from proceeds received from our financial assets.

Net cash used in investing activities for the six months ended June 30, 2026 increased by $32.0 million compared to net cash used in investing activities for the six months ended June 30, 2025. This increase was driven by an increase in our purchases of financial instruments assets of $56.5 million, partially offset greater by greater proceeds received from those investments financial assets of $19.3 $19.2 million in the six months ended June 30, 2026 compared to June 30, 2025 and lower payments related to our license license-related intangible assets in the period ending June 30, 2026 compared to the same period in 2025.

Financing Activities

During the year ended December 31, 2025, financing activities provided $197.0 million of cash inflows. The cash inflows primarily related to the proceeds received from closing both the first and second tranche of our Series A financing round for a total inflow of $200.0 million, partially offset by the payment of $2.2 million of transaction costs and payments on lease obligations of $0.8 million.

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During the six months ended June 30, 2026, financing activities provided $108.6 million of cash inflows, resulting primarily from cash inflows from the proceeds received from closing the first tranche of our Series B financing round of $110.0 million, partially offset by the payment of $1.2 million from transaction costs and payments on our lease obligations.

During the six months ended June 30, 2025, financing activities provided $73.8 million of cash inflows, resulting primarily from cash inflows from the proceeds received from closing the first tranche of our Series A financing round of $75.0 million, partially offset by the payment of $1.0 million from transaction costs and payments on our lease obligations.

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We expect our future funding requirements

requirements to continue to increase over time in connection with our ongoing research and development activities related to our product candidates. To the extent we obtain regulatory approval for any of our product candidates, we also expect to incur significant expenses to market, sell and distribute our approved products. Additionally, upon successful completion of this offering, we will incur additional costs associated with operating as a public company.

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Scope, progress, results and costs of our ongoing and planned preclinical nonclinical studies and clinical trials for our product candidates ∎ The timing and amount of milestone and royalty payments we may be required to make under any current or future license and collaboration agreements ∎ The extent to which we in-license or acquire additional product candidates and technologies ∎ The number and development requirements of other product candidates we may pursue ∎ Expense, timing and outcome of regulatory review of our product candidates ∎ Costs and timing of future commercialization activities, including manufacturing, marketing, sales and distribution, if any product candidates receive regulatory approval ∎ Whether we receive any revenue from commercialization of our product candidates, if we receive regulatory approval ∎ Our ability to establish additional license and collaboration agreements or other strategic partnerships ∎ Costs and timing of preparing, filing and defending patent applications, maintaining and enforcing our intellectual property rights As of June 30, 2026, we had total cash, cash equivalents and marketable securities of $207.3 million. Based on our current plans and business conditions, we believe our existing cash, cash equivalents and marketable securities, together with the net proceeds from this offering, will be sufficient to enable us to fund our operating expenses and capital expenditure requirements through .

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Payments due upon cancellation generally consist only of payments for services provided or expenses incurred, including non-cancellable obligations of the service providers, up to the date of cancellation.

payment obligations that may be incurred and may be owed to the licensors in our license and collaboration agreements, based on the achievement of certain development and sales-related milestones. As of June 30, 2026, we have already made achieved two development-milestone-related development-milestones and made the related payments of $5.0 million each, or $10.0 in 2025 and $5.0 million total, in July 2026, related to our WIN378 License. Depending on the license, we may also be required to pay low single to low double-digit royalty payments to the counterparties in our license and collaboration agreements.

We are party to various lease agreements, including

We are party to various lease agreements, including for our office space in Basel, Switzerland and certain research and development related assets used in our ongoing clinical trials.

Additional information on our

Additional information on our lease arrangements is available in our consolidated financial statements, which are included elsewhere in this prospectus.

Other Research and Development Obligations

In the normal course of our business, we enter into arrangements with CROs, CDMOs and other third-party vendors for preclinical nonclinical studies, clinical trials, testing and manufacturing services. These contracts are generally cancellable by us upon prior notice. Payments due upon cancellation generally consist only of payments for services provided or expenses incurred, including non-cancellable obligations of the service providers, up to the date of cancellation.

Critical Accounting Policies,

Estimates and Significant Judgements

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and 19 more changes in the filing

Business 220 changes

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We use the term "ultra-long-acting" to refer to biologics engineered to remain in the body substantially longer than conventional antibodies. A pre-planned interim analysis of the Phase 2 portion of the POLARIS-1 study demonstrated a half-life of up to 75 days, enabling dosing as infrequently as twice a year, compared with the every-two-week to monthly dosing intervals required by most approved biologic therapies in respiratory disease.

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It has two-fold improved in vitro potency relative to Tezspire , tezepelumab. In a head-to-head cell-based assay using human blood cells, WIN378 was approximately twice as potent as Tezspire , tezepelumab, at blocking TSLP-driven release of the inflammatory marker TARC. Based on the interim analysis of the Phase 2 portion of POLARIS-1, WIN378 was four times more potent than Tezspire based on the EC 50 for FeNO. This is an indirect comparison and does not represent results from a head-to-head study; cross-trial comparisons should be interpreted with caution.

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WIN378 was well tolerated, with favorable safety results, and there were no treatment-related serious adverse events, withdrawals or discontinuations observed as of the cut-off date. Adverse events were balanced between active arms and placebo.

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The primary study results at week 24 are expected in the first half of 2027. The final study results at week 48 are expected to be available in the second half of 2027. Two twice-yearly dose levels were selected for the Phase 3 portion of POLARIS-1, which was initiated in September 2026 with topline results at week 48 expected in the second half of 2028. In September 2026, we also plan to initiate initiated study start-up activities for a second Phase 3 study (POLARIS-2), which is planned to begin patient recruitment in the first half of 2027, with topline results expected in the second half of 2029.

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Based on published and public statements from other companies as well as results from trials to date in which WIN378 was well-tolerated in patients and no serious adverse events deemed to be study-related were reported, we believe that WIN378, if it produces favorable the safety and efficacy data needed to support approval in future pivotal trials, has the potential to be the first ultra-long-acting treatment targeting TSLP to seek approval in the United States. However, the results from early trials of a product candidate may not be predictive of the results that will be obtained in later stage trials of the product candidate.

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WIN027 is currently in a Phase 1 healthy volunteer study with INDs open in the United States, Australia and the PRC assessing safety and pharmacokinetics. We expect that the next data readout for WIN027 will be full results of this study in the first half of 2027. Based on blinded interim data as of June 2026, we have observed a 62-day half-life, low immunogenicity, and favorable safety results, low rate of injection site reactions with full pharmacokinetic and immunogenicity data expected in the first half of 2027.

We plan to initiate multiple initiated study start-up activities in September 2026 for our two global Phase 2 2b studies, which are planned to begin patient recruitment in the first half of 2027, including a globally conducted, dose-ranging study in COPD fully powered on the registrational endpoint of exacerbation rate ratio. in the first half of 2027. Our Phase 2b trial is designed with registrational-quality features, including treatment period, exacerbations as primary endpoint, appropriate key secondary endpoints including lung function, hierarchical type 1 error control, independent data and safety monitoring, and a population aligned with the intended indication. We also plan to initiate a global atopic dermatitis study in the first half of 2027 with topline results expected in the second half of 2028. Additionally, based on our knowledge, Qyuns plans to initiate initiated their Phase 2 studies in asthma, CRSwNP, and atopic dermatitis and CRSwNP in September 2026 in the PRC and plans to begin a Phase 2 study in asthma by the second half end of 2026. with Topline results from these studies are expected in over the course of 2027 and 2028.

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AD=atopic dermatitis, COPD=chronic obstructive pulmonary disease, HV=healthy volunteer, TLR=topline results, W=week; remaining studies, not funded by the expected IPO proceeds, are already funded Additional bispecific programs are in the lead optimization phase. The current program is a next-generation bispecific targeting T2 and non-T2 pathways, with two complementary cytokines. Work to date has included the evaluation of various formats, production at small scale, and the evaluation of productivity, purity and light chain mispairing. Further work has characterized the blocking of both cytokines and a HELA cell-based potency assay has been developed and used to compare the bispecifics' potencies to monospecific benchmarks. Of the three formats evaluated, a lead pre-clinical nonclinical target format has been identified and selected, with potential across skin and respiratory indications, including atopic dermatitis, asthma, COPD and other inflammatory and fibrotic skin and lung diseases. We expect to initiate Phase 1 clinical development for these potential skin and respiratory indications in the next 18 months, subject to standard regulatory requirements. The lead format demonstrating benchmark-comparable affinity, cellular potency and manufacturability is currently being engineered for half-life extension prior to characterization in nonhuman primate studies.

We were founded in 2024 and launched in January

We were founded in 2024 and launched in January 2025. Our management team has significant experience spanning drug discovery and development, global commercialization, finance, business development, and corporate strategy. We have collectively been responsible for the discovery, development, or commercialization of over 20 medicines. Our management team has worked together previously, including at VectivBio and Therachon, where we built each biotechnology company from inception through public offerings and eventually strategic acquisitions, consistently meeting or exceeding corporate objectives. Our executive leadership is described under " Our team " below.

We have not generated any product revenue to date and have funded our operations principally through private placements of equity. As of June 30, 2026, we had cash, cash equivalents and marketable securities of $207.3 million.

Our goal is to develop, obtain regulatory approval, and

Our goal is to develop, obtain regulatory approval, and commercialize potentially novel immunology therapeutics for patients underserved by today's standard of care in asthma, COPD, atopic dermatitis, and other immunological conditions. We estimate that these diseases collectively affect approximately 100 million people in the United States, EU5, and Japan and more than 8 million are eligible for biologics treatment. Based on our internal estimates, we believe this represents an estimated $60 billion peak market opportunity for biologic therapies. Key elements of our novel approach, which we believe has the potential to improve the outcomes of the current generation of biologics in inflammatory lung and skin diseases for these patients, are below.

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Advance WIN378, our lead ultra-long-acting anti-TSLP monoclonal antibody, through clinical development for the treatment of asthma, a severe disease with low adherence to short-acting biologics. We believe WIN378 has the potential to be a differentiated anti-TSLP therapy based on its potent inhibition of a clinically validated target, twice-yearly dosing profile, low immunogenicity and unique dual-site binding to the TSLP ligand. Through our ongoing Phase 2/3 POLARIS-1 asthma study, we aim to establish WIN378 as a differentiated treatment option for patients with severe asthma, including those with low eosinophil counts who remain underserved by current biologic therapies. In the pre-planned interim analysis of the Phase 2 portion of POLARIS-1, demonstrated significant improvements in lung function and airway inflammation were observed with twice-yearly dosing of WIN378. Near maximal effects were seen as early as week 2 and sustained through week 24. WIN378 was well tolerated with favorable safety results — there were no treatment-related serious adverse events, withdrawals or discontinuations; adverse events were balanced between active arms and placebo, with low rates of injection site reactions and antidrug antibodies. The pharmacology analysis demonstrated a half-life of up to 75 days, with clinical effects consistent with twice-yearly dosing. The next data readout is the primary analysis at week 24 in the first half of 2027. The final study results at week 48 will be available in the second half of 2027. The Phase 3 portion of the study was initiated in September 2026, evaluating two twice-yearly dose levels of WIN378, with topline results at week 48 expected in the second half of 2028. In September 2026, study start-up activities were initiated for a second Phase 3 study in asthma (POLARIS-2), which is planned to begin patient recruitment in the first half of 2027, with topline results expected in the second half of 2029.

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Advance WIN027, our long-acting anti-TSLP anti-IL-13 bispecific antibody, through clinical development for the treatment of COPD and atopic dermatitis, diseases in which there is the potential for significant improvement over currently approved biologics . We believe dual blockade of TSLP and IL-13 may provide deeper and more durable disease control than inhibition of either pathway alone. We are advancing WIN027 through an ongoing Phase 1 trial in healthy volunteers. Based on blinded interim data as of June 2026, we have observed a 62-day half-life, low immunogenicity and favorable safety results, low rate of injection site reactions, with full pharmacokinetic and immunogenicity data expected in the first half of 2027. We plan to initiate a global Phase 2b in COPD, fully powered on the registrational endpoint of exacerbation rate ratio, in the first half of 2027. Topline results are expected in the first half of 2029. We also plan to initiate a global Phase 2 study in atopic dermatitis in the first half of 2027 with topline results expected in the second half of 2028. Additionally, based on our knowledge, Qyuns plans to initiate initiated their Phase 2 studies in asthma, CRSwNP, and atopic dermatitis and CRSwNP in September 2026 in the PRC and plans to begin a Phase 2 study in asthma by the second half end of 2026. with Topline results from these studies are expected in over the course of 2027 and 2028.

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The management team has significant experience working together and delivering results at prior companies including VectivBio and Therachon. Collectively, they have developed and launched over 20 medicines (including Jakafi, Ocrevus, Vabysmo, Evrysdi, Enspryng and Vyvanse), and raised over $1 billion in capital, including two initial public offerings on Nasdaq, and executed two trade sales—VectivBio to Ironwood Pharmaceuticals in 2023 for $1.2 billion and Therachon to Pfizer in 2019 for up to $810 million. We believe our experience collaborating closely at prior companies provides us with a meaningful advantage and demonstrates our collective ability to execute. This experience, combined with our programs, position positions us for success as we efficiently build the broader organization needed to bring these therapeutics to market. See "Management" for further details on the experience of our management team.

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Windward Bio holds global rights to WIN378 excluding Greater China and certain Asian markets ** Exclusivity based on pending applications and anticipated patent extensions *** Asthma and CRSwNP Phase 2 studies are planned in the PRC only, conducted and funded by Qyuns Therapeutics; see "—WIN027" on page 119 for more information **** Lead optimization stage with potential in respiratory and dermatology; see "—Additional bispecific programs" on page 119 for more information IP=intellectual property, mAb=monoclonal antibody WIN378 is an ultra-long-acting and potentially novel fully human monoclonal antibody that is designed to inhibit the TSLP ligand. This clinically validated target plays a key role in the development and progression of a wide array of immunological diseases, including asthma and COPD. WIN378 has been engineered to achieve half-life extension and silenced effector function. In preclinical nonclinical studies, WIN378 has been observed to have greater potency than the currently approved anti-TSLP treatment, has two binding sites to TSLP and fully overlaps the same binding site as Tezspire , tezepelumab.

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We have licensed the global rights

We have licensed global rights (excluding Greater China) for WIN027 from Qyuns (also known as QX027N) and retain all decision-making rights in our territory.

WIN027 is currently in a Phase 1 HV study with INDs open in the

Despite the relatively limited utilization of

WIN378 is currently being evaluated in POLARIS-1, a Phase 2/3 study in severe uncontrolled asthma. A pre-planned interim analysis from the Phase 2 dose-finding portion of the study was completed in the second half of 2026, and the primary study results at week 24 are expected in the first half of 2027. The final study results at week 48 will be available in the second half of 2027. Following dose selection based on the interim analysis, we initiated the Phase 3 portion of POLARIS-1 in September 2026 with topline results expected in the second half of 2028. and, We have also plan to initiate initiated study start-up activities for a second Phase 3 study (POLARIS-2) which is planned to begin patient recruitment in the first half of 2027 with topline results expected in the second half of 2029. Separately, a Phase 2 study of WIN378 in COPD, SIRIUS, was initiated in June 2026 with topline results expected in the second half of 2027. We have observed the following results in the Phase 1 clinical trial for WIN378: an extended half-life supporting twice-yearly subcutaneous dosing, a low rate of antidrug antibodies, and favorable safety and tolerability results up to the highest dose tested. no treatment-related serious adverse events were observed. In the interim analysis of the Phase 2 portion of POLARIS-1, WIN378 demonstrated significant improvements in lung function and airway inflammation were observed with twice-yearly dosing of WIN378. Near maximal effects were seen as early as Week 2 and sustained through Week 24. While these results may not translate to similar safety or efficacy results in the ongoing Phase 3 portions of our POLARIS studies in patients with asthma or our SIRIUS Phase 2 study in patients with COPD, we believe WIN378 is differentiated from currently approved treatments primarily through its potential for twice-yearly subcutaneous dosing.

Based on published and public statements from other companies as well as results from trials to date in which WIN378 was well tolerated in patients and no serious adverse events deemed to be study-related were reported, we believe that WIN378, if it produces favorable the safety and efficacy data needed to support approval in future pivotal trials, has the potential to be the first ultra-long-acting treatment targeting TSLP to seek approval in the United States. However, the results from early trials of a product candidate may not be predictive of the results that will be obtained in later stage trials of the product candidate.

We have licensed the global rights (excluding Greater China and certain Asian countries) for WIN378 from Kelun-Biotech (also known as SKB378) and HBM (also known as HBM9378). Both companies equally own the underlying WIN378 intellectual property, are equal parties to the license agreement with Windward Bio and share equal rights in their territory. We retain all decision-making in our territory and have certain decision rights in their territory.

WIN027 is an ultra-long-acting, potentially

WIN027 is an ultra-long-acting, potentially novel, humanized bispecific monoclonal antibody with high-binding affinity for TSLP and IL-13, two well-validated targets in immunological conditions. WIN027 has been engineered to achieve an extended half-life that enables less frequent dosing. Through this dual, long-acting inhibition, WIN027 is designed to treat conditions such as COPD and atopic dermatitis, potentially delivering deeper and more durable disease control than existing biologics. WIN027 has the potential to expand our portfolio to dermatological diseases, including atopic dermatitis.

licensed global rights (excluding Greater China) for WIN027 from Qyuns (also known as QX027N) and retain all decision-making rights in our territory. Although we do not conduct or fund, and have no direct economic rights with respect to, Qyuns-sponsored programs in the PRC, the data generated from these clinical trials directly informs the design and conduct of our WIN027 clinical development programs and potential regulatory filings outside Greater China, and more importantly, the potential value of WIN027 outside of Greater China. Results from a trial of WIN027 anywhere in the world will impact and be relevant to the value and potential of WIN027 on a global basis. Under our license and collaboration agreement with Qyuns, Qyuns is required to provide us with copies of and access to data, results and supporting documentation generated from its development activities. We have the right to use and reference such information in connection with our development of WIN027 and our pursuit and maintenance of regulatory approvals outside Greater China, where we hold exclusive development and commercialization rights. Furthermore, pursuant to our license and collaboration agreement with Qyuns, we and Qyuns have established a joint steering committee that oversees and coordinates the development, manufacture and commercialization of compounds and product candidates, including cross-territory clinical trials.

WIN027 is currently in a Phase 1 HV study with INDs open in the United States, Australia and the PRC assessing safety and pharmacokinetics. We expect that the next data readout for WIN027 will be the full Phase 1 results in the first half of 2027. Based on blinded interim data as of June 2026, we have observed a 62-day half-life, low immunogenicity, a low rate of injection site reactions, and favorable safety and tolerability results, have not observed any treatment-related serious adverse events, with full pharmacokinetic and immunogenicity data expected in the first half of 2027. We plan to initiate multiple Phase 2 studies. We plan to conduct initiated study start-up activities in September 2026 for a global, dose range dose-ranging finding Phase 2 study in COPD, fully powered on the registrational endpoint of exacerbation rate ratio, which we plan is planned to initiate begin patient recruitment in the first half of 2027. Topline results are expected in the first half of 2029. Our Phase 2b trial is designed with registrational-quality features, including treatment period, exacerbations as primary endpoint, appropriate key secondary endpoints including lung functional, function, hierarchical type 1 error control, independent data and safety monitoring, and a population aligned with the intended indication. We also plan to initiate initiated study start-up activities in September 2026 for an additional Phase 2 study in atopic dermatitis which is planned to begin patient recruitment in the first half of 2027 with initial data expected in the first half of 2028 . Additionally, based on our knowledge, Qyuns plans to initiate initiated their Phase 2 studies in asthma, CRSwNP, and atopic dermatitis and CRSwNP in September 2026 in the PRC and plans to begin a Phase 2 study in asthma by the second half end of 2026, with the year. Topline results from these studies are expected in over the course of 2027 and 2028.

Additional bispecific programs are

Additional bispecific programs are in the lead optimization phase. The current program is a next-generation bispecific targeting T2 and non-T2 pathways, with two complementary cytokines. Work to date has included the evaluation of various formats, production at small scale, and the evaluation of productivity, purity and light chain mispairing. Further work has characterized the blocking of both cytokines and a HELA cell-based potency assay has been developed and used to compare the bispecifics' potencies to monospecific benchmarks. Of the three formats evaluated, a lead pre-clinical nonclinical target format has been identified and selected, with potential across skin and respiratory indications, including atopic dermatitis, asthma, COPD and other inflammatory and fibrotic skin and lung diseases. We expect to initiate Phase 1 clinical development for these potential skin and respiratory indications in the next 18 months, subject to standard regulatory requirements. The lead format demonstrating benchmark-comparable affinity, cellular potency and manufacturability is currently being engineered for half-life extension prior to characterization in nonhuman primate studies.

WIN378 is initially being developed for the treatment of

initially being developed for the treatment of respiratory diseases with a focus on asthma and COPD. WIN027 is being developed for the treatment of respiratory disease and atopic dermatitis. Although these indications encompass large and growing markets, we estimate that the biologics treatment rate among eligible patients remains low—approximately 20% in severe asthma, approximately 1% in moderate-to-severe COPD, and approximately 15% in moderate-to-severe atopic dermatitis.

By contrast, biologic use is more established in

By contrast, biologic use is more established in certain other immune-mediated diseases. We estimate that biologic use among eligible patients averages approximately 40% across Crohn's Disease, Ulcerative Colitis, Rheumatoid Arthritis and Psoriatic Arthritis, driven in part by the length of time biologics have been on the market, the number of available treatment options, and the ability of biologics to address the unmet needs in these diseases. We believe there is potential for the biologic treatment rate to increase in asthma, COPD, and atopic dermatitis over time as more treatments become available, efficacy and dosing convenience standards improve, and treatments are indicated for more sub-populations of patients.

Despite the relatively limited utilization of biologic therapies in severe asthma, the asthma biologic therapeutics market is already substantial and is expected to grow as use of advanced therapies expands. In 2025, we estimate global sales of biologics for severe asthma were approximately $14 billion and we estimate they will reach $30 billion at peak in combination with COPD biologic treatment. We believe that atopic dermatitis represents a portfolio expansion opportunity beyond asthma and COPD. In 2025, global sales of biologics and novel oral treatments for atopic dermatitis were approximately $15 billion and we estimate they will reach $30 billion at peak as more eligible patients receive treatment.

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In asthma, COPD, and atopic dermatitis; internal management estimates derived from third-party data; market opportunity represents estimates of peak global sales (ex-China).

The following figure shows our internal view of the addressable markets for our programs.

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Two biomarkers are used to identify and monitor

The most important biological distinction is between type-2 and non-type-2 asthma, which is defined by the kind of inflammation present in the airways. Type-2 asthma is driven by the activation of a type-2 immune response and its signature cytokines, principally IL-4, IL-5, and IL-13.

The most important biological distinction is between type-2 and non-type-2 asthma, which is defined by the kind of inflammation present in the airways. Type-2 asthma is driven by the activation of a type-2 immune response and its signature cytokines, principally IL-4, IL-5, and IL-13. These cytokines increase production of immunoglobulin E, or IgE, the antibody central to allergic reactions; recruit and activate eosinophils, a type of white blood cell that drives airway inflammation; and raise the level of nitric oxide in exhaled breath. Type-2 disease itself takes more than one form. It includes allergic asthma, which is typically allergen-driven and often begins in childhood, and later-onset eosinophilic asthma, which can arise in adulthood without a clear allergic trigger. A number of biologics target this subgroup including the anti-IL-5 class (Nucala , mepolizumab; Fasenra , benralizumab; and Exdensur , depemokimab-ulaa), the anti-IL-4/IL-13 class (Dupixent , dupilumab), the anti-IgE class (Xolair , omalizumab) as well as anti-TSLP (Tezspire , tezepelumab).

Two biomarkers are used to identify and monitor type-2 inflammation in clinical practice: the number of eosinophils in the blood, and the fraction of exhaled nitric oxide, or FeNO, a marker of type-2 airway inflammation measured in the breath. High levels of either point to type-2 disease and, importantly, help to predict which patients are likely to respond to type-2-targeted therapies. Low levels characterize non-type-2 disease.

Non-type-2 asthma is

Non-type-2 asthma is defined by the relative absence of this type-2 signature. The inflammation is instead associated with other arms of the immune system, principally Th1 and Th17 responses, and the airway inflammation is often neutrophilic rather than eosinophilic or shows little inflammatory cell infiltrate at all. As a result, patients with non-type-2 asthma tend to have lower eosinophil counts and lower exhaled nitric oxide.

Most patients with asthma manage the disease well with inhaled corticosteroids, usually combined with bronchodilators.

Most patients with asthma manage the disease well with inhaled corticosteroids, usually combined with bronchodilators. Patients whose disease remains uncontrolled despite high-dose inhaled therapy are considered to have severe asthma, accounting for a disproportionate share of exacerbations, hospitalizations, treatment burden and cost. Within severe asthma, the type-2 subgroup has benefited substantially from targeted biologic therapies directed at the type-2 cytokines and IgE.

Patients with non-type-2 asthma tend

with non-type-2 asthma tend to respond poorly to inhaled corticosteroids, and they have historically been poor candidates for the available biologics, which act on the type-2 pathway and offer little where type-2 biomarkers are low. The anti-TSLP antibody, Tezspire , tezepelumab, is the only biologic approved for all patients with severe, uncontrolled asthma, including patients with both high-T2 and low-T2 status. Severe non-type-2 asthma therefore remains among the most significant areas of unmet need in respiratory medicine, and it is a central focus of the rationale for our program in addition to addressing the broader severe asthma, where Tezspire , tezepelumab, has demonstrated significant clinical benefit.

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Within this severe segment, our market research indicates several key unmet needs that we believe can be addressed by our programs.

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The following figure summarizes the number of dosing periods per year for approved respiratory biologics alongside real-world persistency.

dosing periods per year for approved respiratory biologics alongside real-world persistency.

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Asthma Biologic Use in a US Claims Database. Ann Allergy Asthma Immunol. 2021 December; 127(6): 648–654 3. Two-year persistence and compliance with osteoporosis therapies among postmenopausal women in a commercially insured population in the United States.Arch. Osteoporos.2017,12, 22. 4. www.leqviohcp.com 5. Adherence to and Persistence with Disease-Modifying Therapies for Multiple Sclerosis Over 24 Months: A Retrospective Claims Analysis. Neurol Ther, 2022 11:337–351 Poor persistency can result in worse outcomes for patients with severe asthma, including increased exacerbations and suboptimal symptom control. A study demonstrated that patients who discontinued asthma biologics had a 47% increase in emergency department visits and a 71% increase in hospitalizations compared to patients who were fully adherent to treatment. Discontinuation of treatment also resulted in significantly increased costs. WIN378 may be able to deliver improved real-world outcomes through improved persistency that reduces the risk of exacerbations.

Discontinuation of treatment also resulted in significantly increased costs. WIN378 may be able to deliver improved real-world outcomes through improved persistency that reduces the risk of exacerbations.

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By contrast, biologic use is more established in

By contrast, biologic use is more established in certain other immune-mediated diseases. We believe biologic use among eligible patients averages approximately 40% across Crohn's Disease, Ulcerative Colitis, Rheumatoid Arthritis, and Psoriatic Arthritis. We believe there is potential for biologic penetration to increase in severe asthma over time as more treatments become available, efficacy and dosing convenience standards improve, and treatments are indicated for more sub-populations of patients. Despite relatively modest current penetration of biologic therapies in severe asthma, the biologic therapeutics market is already substantial and is expected to grow. In 2025, global sales of biologics for severe asthma were approximately $14 billion, and we project the market to reach $30 billion at peak in combination with COPD biologic treatment.

We believe that WIN378 is

We believe that WIN378 is well-positioned to drive this market growth and can achieve a meaningful share of patients treated with biologics.

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COPD is a heterogeneous lung condition

COPD is a heterogeneous lung condition characterized by chronic respiratory symptoms, including shortness of breath, cough, sputum production and disease exacerbations arising from airway abnormalities such as bronchitis or bronchiolitis, and emphysema, which is characterized by damage to the alveoli, the air sacs of the lung where oxygen enters the blood. The result of these symptoms and COPD more generally is a persistent, often progressive airflow obstruction that can produce significant morbidity and mortality, including right-sided heart failure, if not adequately controlled. A systematic review of large population studies estimated that COPD affects approximately 390 million people worldwide, with prevalence continuing to rise. COPD is the third leading cause of death globally, responsible for approximately 3.4 million deaths in 2023.

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mepolizumab's label extends down to BEC ≥ 150 cells/ L. It is administered 12 times per year.

IL-4/IL-13 receptor component, became the first approved biologic for COPD in September 2024, based on the Phase 3 BOREAS and NOTUS trials, which demonstrated 30% and 34% reductions, respectively, in annualized moderate-or-severe exacerbation rates versus placebo in patients with BEC ≥ 300 cells/ L on background triple therapy. It is administered 26 times per year. Nucala (mepolizumab), an anti-IL-5 antibody, was subsequently approved in patients with an eosinophilic phenotype based on the Phase 3 MATINEE and METREX trials, which showed statistically significant reductions in annualized exacerbation rates of 21% and 18%, respectively, in patients with BEC ≥ 300 cells/ L (MATINEE) and across a broader eosinophilic range (METREX); mepolizumab's label extends down to BEC ≥ 150 cells/ L. It is administered 12 times per year.

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We believe WIN378 is well-positioned to address these unmet needs. Because TSLP acts upstream of eosinophil-driven and non-eosinophil-driven inflammatory pathways, we believe an anti-TSLP therapy such as WIN378 has the potential to address a broader COPD population than currently approved biologics, subject to successful clinical validation in our SIRIUS Phase 2 study and any subsequent pivotal trials. WIN378 has been specifically engineered to be ultra-long-acting, providing dosing twice-yearly, which, if approved, would be a significant improvement upon existing standards of care.

We believe WIN027 may

We believe WIN027 may also be able to address these unmet needs. It is a single treatment engineered to potently shut down two central drivers of type-2 inflammation at once—TSLP and IL-13. Because TSLP sits upstream and IL-13 downstream of the same disease pathway, blocking both with one antibody is designed to produce broader, more complete pathway suppression than any single-target biologic. This may be achieved with single-targeted biologics and may be particularly effective in patients with severe disease and lung complications such as mucous plugs.

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Disease Overview, Unmet Need, and Market Opportunity

Atopic dermatitis, also known as atopic eczema, is a chronic, relapsing inflammatory skin disease driven substantially by type-2 inflammation. It is characterized by recurrent eczematous lesions, dry skin, and intense, persistent itch (pruritus), and it follows a fluctuating course of flares and partial remissions rather than a steady state. It is the most common chronic inflammatory skin disease and, among all skin conditions, carries the largest burden of disability as measured by disability-adjusted life-years.

The pathophysiology reflects a self-reinforcing interplay

The pathophysiology reflects a self-reinforcing interplay between epidermal barrier dysfunction and type-2 immune activation, with genetic and environmental factors contributing to both. Barrier impairment is a central feature. The resulting permeability allows increased transepidermal water loss and greater penetration of allergens, irritants, and microbes, which in turn amplifies the immune response. Barrier disruption and external triggers stimulate keratinocytes to release the epithelial alarmins, including TSLP. These alarmins activate dendritic cells and group 2 innate lymphoid cells and polarize naive T cells toward a Th 2 phenotype, positioning TSLP in particular as an upstream initiator that sits proximal to the downstream effector cascade. The Th2 and ILC2 compartments produce the central effector cytokine IL-13, which signals through JAK-STAT pathways to drive IgE eosinophil recruitment, and further suppression of barrier proteins and antimicrobial peptides. IL-13 is the dominant cytokine in lesional skin and is a principal driver of the tissue remodeling and barrier defects that characterize chronic disease.

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We believe WIN027's dual TSLP and IL-13 mechanism and half-life-extended design, which is intended to support every-12-week or less frequent subcutaneous dosing, has the potential to address such needs—offering a biologic alternative that is designed for less-frequent administration than currently approved IL-4R a and IL-13 therapies. If validated in clinical trials, we believe this profile could position WIN027 competitively in the atopic dermatitis biologics market alongside established and investigational anti-IL-13 and anti-IL-4R a therapies. WIN027 is currently in a Phase 1 healthy volunteer study with INDs open in the United States, Australia and the PRC assessing safety and pharmacokinetics. Based on blinded interim data as of June 2026, we have observed a 62-day half-life, low immunogenicity and favorable safety results, low rate of injection site reactions, with full pharmacokinetic and immunogenicity data expected in the first half of 2027.

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TSLP is a signaling protein (a cytokine) released by the

epithelial cells that line the body's barrier surfaces, most importantly, the airways of the lung, the lining of the gastrointestinal tract, and the skin. These surfaces are the body's first point of contact with the outside environment.

TSLP belongs to a small family of cytokines, together with IL-25 and IL-33, that are known as "alarmins" because they act as early warning signals.

TSLP is a signaling protein (a cytokine) released by the epithelial cells that line the body's barrier surfaces. Most importantly, the airways of the lung, the lining of the gastrointestinal tract, and the skin. These surfaces are the body's first point of contact with the outside environment. TSLP belongs to a small family of cytokines, together with IL-25 and IL-33, that are known as "alarmins" because they act as early warning signals. Epithelial cells produce TSLP in response to a wide variety of environmental triggers, including allergens, airborne pollutants such as cigarette smoke, viruses, bacteria, and direct physical injury to the tissue. Due to this profile, TSLP is among the first molecules the body releases when a barrier surface is disturbed. Other immune cells that respond to allergens, pollutants and mechanical damage and release TSLP are cells such as dendritic cells, basophils, and mast cells that are responsible for the body's immune defense system.

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breadth matters across the inflammatory pathways that these diseases share. Some patients have disease with a strong type-2 character, marked by elevated biomarkers such as blood eosinophils or exhaled FeNO.

Allergen-driven disease provides a further illustration. In allergic airway disease, the immune system reacts to inhaled allergens such as house dust mite or pollen.

This breadth matters across the inflammatory pathways that these diseases share. Some patients have disease with a strong type-2 character, marked by elevated biomarkers such as blood eosinophils or exhaled FeNO. Others have low-type-2 disease, in which these biomarkers are absent or only modestly raised. Such patients make up a substantial share of the severe airway-disease population and have historically had few effective targeted options, because most approved biologics are effective mainly where type-2 biomarkers are high. Because TSLP influences airway inflammation through mechanisms that extend beyond the classic type-2 cytokines, including effects on the structural cells of the airway, on airway hyper-responsiveness, and on non-type-2 inflammatory pathways, inhibiting TSLP offers a rationale for treating patients across this spectrum.

Allergen-driven disease provides a further illustration. In allergic airway disease, the immune system reacts to inhaled allergens such as house dust mite or pollen. TSLP is a key early participant: it acts on the dendritic cells that first present allergens to the body, steering the resulting response toward the type-2 pattern, and it heightens the activity of other allergy-driving cells such as mast cells and basophils. Blocking TSLP therefore has the potential to interrupt allergen-driven disease at an earlier point than therapies acting only on later steps.

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TSLP has been implicated in these processes through its action on structural cells. In preclinical nonclinical and laboratory studies, TSLP promotes the proliferation and pro-inflammatory activity of airway smooth muscle cells and fibroblasts and contributes to the mucus-cell and fibrotic changes that characterize the remodeled airway. Because TSLP influences both the inflammatory cascade and the structural cells that carry out remodeling, inhibiting it offers a rationale for reaching a dimension of disease that lies largely beyond the type-2 cytokines, and beyond the effector-focused biologics that act only on them.

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Anti-TSLP blockade has demonstrated meaningful reductions in exacerbations in both asthma and, more recently, COPD, supporting TSLP as a clinically validated target. Based on the results observed in separate clinical studies, Tezspire , tezepelumab, reductions in annualized asthma exacerbation rates were directionally higher relative to dupilumab in all key sub-populations defined by eosinophilic counts.

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Those effector functions are extensive. In the airway, IL-13 recruits eosinophils into the tissue, promotes the class switching that generates IgE (the antibody central to allergic responses), stimulates the goblet cells that produce airway mucus, and contributes to the structural changes of airway remodeling, including the smooth-muscle and fibrotic changes described above. Both TSLP and IL-13 are elevated in the airways of patients with asthma, and the level of each correlates with disease severity and with impaired lung function. These observations suggest that both cytokines are active participants in human disease rather than incidental markers, and that they operate at different levels of the same pathway. TSLP acts upstream to initiate and shape the type-2 response and IL-13 acts downstream to execute many of its negative consequences.

Both TSLP and IL-13 are elevated in the airways of patients with asthma, and the level of each correlates with disease severity and with impaired lung function. These observations suggest that both cytokines are active participants in human disease rather than incidental markers, and that they operate at different levels of the same pathway. TSLP acts upstream to initiate and shape the type-2 response and IL-13 acts downstream to execute many of its negative consequences.

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Management 90 changes

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The following table sets forth the name

name and position of each of our executive officers and directors, as well as their respective ages as of July 24, October 9, 2026.

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Claudia D'Augusta, Ph.D. Dr. D'Augusta has served as our Chief Financial Officer since January 2025. Previously, Dr. D'Augusta served as Chief Financial Officer of VectivBio Holding AG through its acquisition by Ironwood Pharmaceuticals (Nasdaq: IRWD), from July 2019 to January 2024, where she was responsible for the company's overall financial strategy and growth.

Omar Khwaja, M.D., Ph.D. Dr. Khwaja has served as our Chief Medical Officer since January 2025.

Claudia D'Augusta, Ph.D. Dr. D'Augusta has served as our Chief Financial Officer since January 2025. Previously, Dr. D'Augusta served as Chief Financial Officer of VectivBio Holding AG through its acquisition by Ironwood Pharmaceuticals (Nasdaq: IRWD), from July 2019 to June 2023, where she was responsible for the company's overall financial strategy and growth. From January 2019 to July 2019, prior to its acquisition by Pfizer Inc. (NYSE: PFE), Dr. D'Augusta was the Chief Financial Officer at Therachon Holding AG. From February 2011 to June 2018, prior to becoming its General Manager, Dr. D'Augusta served as Chief Financial Officer of TiGenix, now owned by Takeda Pharmaceutical Company Ltd. (NYSE: TAK), leading TiGenix's initial public offering in 2016. From April 2004 to February 2011, Dr. D'Augusta served as Chief Financial Officer of Cellerix before being acquired by TiGenix. Dr. D'Augusta holds a B.Sc. in Economics and a Ph.D. in Business Administration from Bocconi University in Milan, Italy.

Omar Khwaja, M.D., Ph.D. Dr. Khwaja has served as our Chief Medical Officer since January 2025. Previously, Dr. Khwaja served as Chief Medical Officer at VectivBio Holding AG from May 2021 to January 2025, June 2023, where he oversaw drug development and medicine, and Chief Medical Officer and Head of Research & Development at Voyager Therapeutics (Nasdaq: VYGR) from April 2019 to May 2021. Previously, from January 2013 to April 2019, he served as Global Head of Rare Diseases and Neuroscience Translational Medicine at F. Hoffmann-La Roche AG (OTC: RHHBY). Preceding Dr. Khwaja's industry experience in drug development, he practiced medicine and taught in academia for over a decade, including as Director of the Clinical Neurogenetics program at Boston Children's Hospital and as a member of faculty at Harvard Medical School. He is a fellow of the Royal College of Physicians, serves as a chair or member of a number of industry and foundation scientific or clinical advisory boards, and is also part of the advisory board for Pureos Bioventures. Dr. Khwaja received his M.D. and Ph.D. in Human Molecular Genetics from the University of Cambridge.

Harris. Mr. Harris has served as our Chief Operating Officer since January 2025. Previously, Mr. Harris served as Chief Commercial Officer of VectivBio Holding AG from November 2019 to December July 2023, where he led program management, prelaunch, and commercialization planning for apraglutide prior to the company's sale to Ironwood Pharmaceuticals (Nasdaq: IRWD). Before that, Mr. Harris was at Incyte Corporation (Nasdaq: INCY) for more than ten years, most recently as Group Vice President of Global Product Strategy and Strategic Planning from January 2017 through October 2019. From June 2015 to January 2017, he served as Vice President of Global Product Strategy. Prior to this role, he served as Vice President of Commercial from February 2009 through June 2015 where he built and led most of the U.S. commercial functions for the launch of Jakafi. Previously, Mr. Harris held roles of increasing responsibility at Pfizer Inc. (NYSE: PFE) across the company's HIV and oncology portfolios. Additionally, before that, he served in commercial development and marketing roles at Bristol-Myers Squibb (NYSE: BMY) in HIV and oncology. Mr. Harris began his career in management consulting at PRTM and subsequently joined Parexel in a marketing and strategy role. Mr. Harris holds an M.B.A. from the Kellogg Graduate School of Management at Northwestern University and a B.A. in Biology from Cornell University.

Scott Applebaum. Mr. Applebaum has served as our Chief Legal and Corporate Development Officer since January 2025. Most recently, Mr. Applebaum served as Chief Legal and Business Officer of VectivBio Holding AG from August 2021 to December July 2023, leading the company's sale to Ironwood Pharmaceuticals (Nasdaq: IRWD). Prior to that, he served as Chief Legal and Compliance Officer and Senior Vice President of Regulatory Affairs at Trevena, Inc. (OTC: TRVN) from February 2020 to August 2021, where he played a key role in gaining FDA approval for their first commercial product, Olinvyk. Previously, he served as President of Context Therapeutics (Nasdaq: CNTX) from September 2017 to June 2019 and was General Counsel at Vitae Pharmaceuticals from July 2016 to December 2016, where he was instrumental in their sale to Allergan. Formerly, he was Chief Legal Officer for Medgenics from September 2014 to July 2016, a rare genetic disease company. Mr. Applebaum spent ten years at Shire, where his roles included heading up their global legal group, managing their neuroscience portfolio outside of the United States as SVP of the Neuroscience Business Unit and leading the implementation and execution of the regulatory strategy for all of Shire's specialty pharmaceutical products worldwide as SVP of Global Regulatory Affairs, Quality Assurance and Compliance. Previously, he was Senior Counsel for medicines and medical imaging at Bristol Myers Squibb (NYSE: BMY). Prior to his career in the biopharmaceutical industry, Mr. Applebaum was a lawyer at Dechert LLP. Mr. Applebaum also served on the board of directors of Cingulate Inc. (Nasdaq: CING) from August 2022 to November 2023. Mr. Applebaum received a J.D. from Stanford Law School and a B.S. in Economics, Finance and Accounting from the Wharton School of the University of Pennsylvania.

Previously, he was Senior Counsel for medicines and medical imaging at Bristol Myers Squibb (NYSE: BMY). Prior to his career in the biopharmaceutical industry, Mr. Applebaum was a lawyer at Dechert LLP. Mr. Applebaum also served on the board of directors of Cingulate Inc. (Nasdaq: CING) from August 2022 to November 2023. Mr. Applebaum received a J.D. from Stanford Law School and a B.S. in Economics, Finance and Accounting from the Wharton School of the University of Pennsylvania.

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Previously, Dr. Siddiqi served on the boards of directors of Amolyt Pharma from January 2020 to July 2024, Reviral from June 2021 to June 2022, Asceneuron from July 2024 to March 2025 and VectivBio Holding AG from January 2020 to March 2021.

Dr. Siddiqi received his medical degree from Guy's and St Thomas's Hospital Medical School (now King's College London) and qualified as a chartered accountant from the Institute of Chartered Accountants in England and Wales.

We believe Dr. Siddiqi is qualified to serve on our board of directors because of his extensive experience investing in and serving on the boards of directors of biopharmaceutical companies in Europe and the United States.

Timothy Anderson. Mr. Anderson has served as a member of our board of directors since January 2025. Mr. Anderson has served as a Managing Director at Blue Owl Capital Inc. (NYSE: OWL) since December 2023. From July 2014 to December 2023, he served as a co-founding member and Managing Director of Cowen Healthcare Investments, which was acquired by Blue Owl. Mr. Anderson currently serves on the boards of directors of Nuvig Therapeutics since 2024, Lycia Therapeutics since 2021, F2G since 2020 Anaveon since 2021, and Autobahn Therapeutics since 2020. and Scipher Medicine since 2022. He previously served as a board member or a board observer of Tourmaline Bio from 2023 to 2023, VectivBio Holding AG from 2019 to 2021, Therachon Holding AG from 2018 to 2019, Precision Biosciences, Inc. (Nasdaq: DTIL) from 2018 to 2019, Livongo Health from 2016 to 2019, Cadent Therapeutics from 2018 to 2020, Cullinan Oncology, Inc. (Nasdaq: CGEM) from 2019 to 2021, and Compass Therapeutics (Nasdaq: CMPX) from 2016 to 2020, Anaveon from 2021 to 2026 and Scipher Medicine from 2022 to 2026. Mr. Anderson received his B.A. in Economics and Government & Legal Studies from Bowdoin College. We believe Mr. Anderson is qualified to serve on our board of directors because of his extensive experience investing in and serving on the boards of directors of biopharmaceutical companies.

Naveed I. Siddiqi. Dr. Siddiqi has served as a member of our board of directors since January 2025. Dr. Siddiqi has been employed by Novo Holdings A/S as Senior Partner since January 2021 and joined the investment firm in September 2019. Prior to joining Novo Holdings, Dr. Siddiqi was a Partner at Andera Partners. Dr. Siddiqi has also worked for Nomura Phase4 Ventures, Nomura International, EFG Corporate Finance, KPMG and as a medical doctor in the UK's National Health Service. Dr. Siddiqi has also served on the board of directors of Alentis Therapeutics since April 2023 and F2G since June 2020. Previously, Dr. Siddiqi served on the boards of directors of Amolyt Pharma from January 2020 to July 2024, Reviral from June 2021 to June 2022, Asceneuron from July 2024 to March 2025 and VectivBio Holding AG from January 2020 to March 2021. Dr. Siddiqi received his medical degree from Guy's and St Thomas's Hospital Medical School (now King's College London) and qualified as a chartered accountant from the Institute of Chartered Accountants in England and Wales. We believe Dr. Siddiqi is qualified to serve on our board of directors because of his extensive experience investing in and serving on the boards of directors of biopharmaceutical companies in Europe and the United States.

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Our articles of association that will be in effect immediately prior to the completion of this offering provide that our board of directors shall consist of a minimum of three members and a maximum of nine members. All directors (including the chairperson of the board of directors) are elected to and dismissed from the board of directors exclusively by our general meeting of shareholders. The maximum term of office is one year, extending until completion of the next annual general meeting of shareholders. Re-election is possible. In the event the office of the chairperson of the board of directors is vacant, the board of directors shall appoint a new chairperson from among its members for the remaining term of office. Our board of directors may elect a vice-chairperson from among its members for a term extending until completion of the next annual general meeting of shareholders.

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overseeing and periodically reviewing environmental, social and governance matters relevant to our business and operations;

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reviewing and discussing with management material risks relating to data privacy, technology and information security, as well as our internal controls and disclosure controls and procedures relating to cybersecurity incidents; and reviewing procedures for whistleblowing, internal financial control, financial reporting and risk management.

reviewing procedures for whistleblowing, internal financial control, financial reporting and risk management; and approving any credits and loans to members of our board of directors and our executive committee, as well as to other employees in an amount exceeding $10,000, in each case to the extent permitted under our amended and restated articles of association.

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Our compensation committee will review and

will review and propose to our board of directors our compensation principles as well as the compensation for the members of the board of directors, the Chief Executive Officer and other members of the executive committee. Pursuant to our articles of association, our compensation committee consists of no less than three members of our board of directors.

Following the completion of the offering, our compensation

compensation committee will consist of , and . will serve as chair of the compensation committee. Under Swiss law, the members of our compensation committee must be elected by our general meeting of shareholders and the aggregate amount of compensation of our board of directors and of our executive committee must be approved by our general meeting of shareholders, in each case commencing with our first annual general meeting of shareholders as a public company to be held in 2027. Our board of directors appoints the chair of the compensation committee and in case of any vacancies may appoint substitute members from among the members of the board of directors, in each case until completion of the next annual general meeting of shareholders.

The compensation committee's principal duties and

principal duties and responsibilities will include, among others:

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establishing, adopting, approving, modifying amending, replacing, terminating and overseeing our compensation clawback or similar policies and any required recoupment and disclosure;

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December 31, 2025, the aggregate compensation paid to for the members of our board of directors and our executive officers for services in all capacities was $11.3 million.

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During the year ended December 31, 2025, share-based payments granted to the members of our board of directors and our executive officers accounted for $14.3 million, of which $7.2 million were recognized as expense in the year ended December 31, 2025. Of those share-based payments, 8,605,800 founder shares were subscribed to by members of our board of directors and our executive officers which includes a total of 4,736,843 of founder shares with certain service vesting conditions and performance vesting conditions considered within the scope of IFRS 2, with at a fair value of $3.02. per share. See Note 10 to our audited consolidated financial statements included elsewhere in this prospectus for further details regarding the share-based payments. Share-based payments that are discussed in this paragraph but are outside of the scope of IFRS 2 were not included in Note 10 to our audited consolidated financial statements.

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In connection with this offering, we intend to adopt a non-employee director compensation policy on terms to be determined by our board of directors in consultation with our independent compensation consultant. Under the non-employee director compensation policy, our non-employee directors will be eligible to receive compensation for service on our board of directors and committees of our board of directors, subject to approval of the maximum aggregate amount of compensation of our board of directors by our general meeting of shareholders.

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Share Reserve . Initially, the maximum number of our common shares that may be issued under our 2026 Plan after it becomes effective will not exceed common shares. The maximum number of common shares that may be issued on the exercise of ISOs under our 2026 Plan is common shares.

In , our board of directors adopted, and shareholders at our general meeting of shareholders approved, the 2026 Plan. We expect our 2026 Plan to become effective on the date of this prospectus. Our 2026 Plan came into existence upon its adoption by our board of directors, but no grants will be made under our 2026 Plan prior to its effectiveness. Once our 2026 Plan becomes effective, no further grants will be made under our 2025 Plan.

Awards . Our 2026 Plan provides for the grant of incentive options, or ISOs, within the meaning of Section 422 of the Code, to our employees located in the United States and our parent and subsidiary corporations' employees that are located in the United States, and for the grant of non-statutory ordinary options, or NSOs, share appreciation rights, restricted share awards, restricted share unit awards, performance awards and other forms of awards to our employees, directors and consultants and any of our affiliates' employees and consultants.

Share Reserve . Initially, the maximum number of our common shares that may be issued pursuant to awards under our 2026 Plan after it becomes effective will equal the sum of (i) common shares, plus (ii) the number of common shares subject to outstanding awards under our 2025 Plan and certain founder share repurchase agreements and restricted share purchase agreements that become available for issuance under our 2026 Plan from time to time in accordance with its terms. In addition, the number of common shares reserved for issuance under our 2026 Plan will automatically increase on January 1 of each year for a period of ten years, beginning on January 1, 2027 and continuing through January 1, 2036, in an amount equal to (1) % of the total number of our common shares and any unexercised pre-funded warrants outstanding on December 31 of the immediately preceding year, or (2) a lesser number of common shares determined by our board of directors no later than December 31 of the immediately preceding year. The maximum number of common shares that may be issued on the exercise of ISOs under our 2026 Plan is common shares.

Shares subject to share awards granted under our 2026 Plan

Shares subject to share awards granted under our 2026 Plan that expire or terminate without being exercised in full or that are paid out in cash rather than in shares will not reduce the number of shares available for issuance under our 2026 Plan. Shares withheld under an award to satisfy the exercise, strike or purchase price of a share award or to satisfy a tax withholding obligation will not reduce the number of shares available for issuance under our 2026 Plan. If any of our common shares issued pursuant to a share award are forfeited back to or repurchased or reacquired by us (i) because of a failure to meet a contingency or condition required for the vesting of such shares; (ii) to satisfy the exercise, strike or purchase price of a share award; or (iii) to satisfy a tax withholding obligation in connection with a share award, the shares that are forfeited or repurchased or reacquired will revert to and again become available for issuance under our 2026 Plan.

Plan Administration . Our board of directors, or a duly authorized committee of our board of directors, administers our 2026 Plan. Our board of directors may delegate to one or more of our officers persons or bodies the authority to (i) designate employees recipients (other than officers) to receive specified share awards; and (ii) determine the number of shares subject to such share awards. Under our 2026 Plan, our board of directors has the authority to determine share award recipients, the types of share awards to be granted, grant dates, the number of shares subject to each share award, the fair market value of our common shares, and the provisions of each share award, including the period of exercisability and the vesting schedule applicable to a share award.

Under our 2026 Plan, our board of directors also

Under our 2026 Plan, our board of directors also generally has the authority to effect, with the consent of any materially adversely affected participant, (i) the reduction of the exercise, purchase, or strike price of any outstanding option or share appreciation right; (ii) the cancellation of any outstanding option or share appreciation right and the grant in substitution therefor of other awards, cash, or other consideration; or (iii) any other action that is treated as a repricing under IFRS.

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Acceptable consideration for the purchase of common shares issued upon the exercise of an option will be determined by the administrator and may include (i) cash, check, bank draft or money order; (ii) a broker- assisted cashless exercise; (iii) the tender of our common shares previously owned by the optionholder; (iv) a net exercise of the option if it is an NSO; or (v) other legal consideration approved by the administrator.

The administrator determines the term of options granted under our 2026 Plan, up to a maximum of ten years. Unless the terms of an optionholder's option agreement, or other written agreement between us and the optionholder, provide otherwise, if an optionholder's service relationship with us or any of our affiliates ceases for any reason other than retirement, disability, death, or cause, the optionholder may generally exercise any vested options for a period of three months following the cessation of service. This period may be extended in the event that exercise of the option is prohibited by applicable securities laws. If an optionholder's service relationship with us or any of our affiliates ceases due to death, or an optionholder dies within a certain period following cessation of service, the optionholder or a beneficiary may generally exercise any vested options for a period of 18 months following the date of death. If an optionholder's service relationship with us or any of our affiliates ceases due to disability or retirement, the optionholder may generally exercise any vested options for a period of 12 months following the cessation of service. In the event of a termination for cause, options generally terminate upon the termination date. In no event may an option be exercised beyond the expiration of its term.

Acceptable consideration for the purchase of common shares issued upon the exercise of an option will be determined by the administrator and may include cash, common shares, other awards or property, net settlement (including cashless exercise) or any combination thereof to the extent permissible under applicable law.

Unless the administrator provides otherwise, options or share appreciation rights generally are not transferable except by will or the laws of descent and distribution. Subject to approval of the administrator or a duly authorized officer, an option may be transferred pursuant to a domestic relations order, official marital settlement agreement, or other divorce or separation instrument.

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Share Appreciation Rights . Share appreciation rights are granted under share appreciation right agreements adopted by the administrator.

Performance Awards . Our 2026 Plan permits the

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