Korsana Biosciences reported a $46.43 million net loss for Q3 2026.

Cover page 16 changes

1 unchanged paragraph

Washington, D.C. 20549

WASHINGTON, DC 20549

1 unchanged paragraph

For the quarterly period ended June September 30, 2026

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CYCLERION THERAPEUTICS, INC.

Korsana Biosciences, Inc.

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245 First Street, 18 th Floor , Cambridge , Massachusetts

203 Crescent Street , Bldgs. #3/3A/4 , Suite 503 ,

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Registrant's telephone number, including area code: ( 781 ) 516-2325

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Common Stock, no par value per share

The Nasdaq Capital Market LLC

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As of July 31, 2026 , the registrant had 4,681,351 shares of common stock, no par value, outstanding.

CYCLERION PHARMACEUTICALS, INC.

QUARTERLY REPORT ON FORM 10-Q

FOR THE QUARTER ENDED June 30, 2026

As of November 2, 2026, the registrant had 45,541,358 shares of common stock outstanding.

PART I — FINANCIAL INFORMATION

Financial Statements (Unaudited) 6 changes

Condensed Consolidated Balance Sheets as of June 30, 2026 and December 31, 2025

Condensed Consolidated Statements of Stockholders' Equity for Three and Six Months Ended June 30, 2026 and 2025

Condensed Consolidated Balance Sheets

Condensed Consolidated Statements of Operations and Comprehensive Loss for Three and Six Months Ended June 30, 2026 and 2025

Condensed Consolidated Statements of Convertible Preferred Stock and Stockholders' (Deficit) Equity

Condensed Consolidated Statements of Cash Flows for Six Months Ended June 30, 2026 and 2025

Notes to the financial statements 6 changes

In accordance with an exchange ratio determined in accordance with the terms of the Merger Agreement (the "Exchange Ratio"), at the effective time of the First Merger (the "First Effective Time"), (i) each then-outstanding share of common stock, par value $0.0001 per share, of Pre-Merger Korsana (the "Pre-Merger Korsana common stock") (including shares of Pre-Merger Korsana common stock issued in connection with the Pre-Closing Financing (as defined below)) automatically converted into the right to receive a number of shares of common stock, no par value per share, of Cyclerion (the "Cyclerion common stock") equal to the Exchange Ratio, (ii) each then-outstanding share of Series Seed Preferred Stock, par value $0.0001 per share, of Pre-Merger Korsana (the "Pre-Merger Korsana Series Seed Preferred Stock") was converted into the right to receive a number of shares of Series B Non-Voting Convertible Preferred Stock, no par value, of Cyclerion (the "Series B Preferred Stock"), equal to the Exchange Ratio divided by 1,000, (iii) each-then-outstanding share of Series A Preferred Stock, par value $0.0001 per share, of Pre-Merger Korsana (the "Pre-Merger Korsana Series A Preferred Stock") automatically converted into the right to receive to a number of shares of Cyclerion common stock equal to the Exchange Ratio; provided, that to the extent the shares of Cyclerion common stock otherwise issuable to any holder would exceed such holder's beneficial ownership limitation (initially set at a percentage of up to 9.99% of the outstanding Cyclerion common stock), such holder received, in lieu of the excess shares, pre-funded warrants to purchase an equal number of shares of Cyclerion common stock, subject to adjustment as set forth in the form of the pre-funded warrant, (iv) each then-outstanding option to purchase Pre-Merger Korsana common stock was assumed by Cyclerion and was converted into an option to purchase shares of Cyclerion common stock, adjusted for the Exchange Ratio, (v) each then-outstanding warrant to purchase Pre-Merger Korsana common stock was assumed by Cyclerion and was converted into a warrant to purchase shares of Cyclerion common stock, subject to adjustment as set forth in the Merger Agreement, (vi) each then-outstanding share of Pre-Merger Korsana restricted stock was assumed by Cyclerion, subject to adjustment as set forth in the Merger Agreement, and (vii) each then-outstanding pre-funded warrant to purchase shares of Pre-Merger Korsana common stock was converted into a pre-funded warrant to purchase shares of Cyclerion common stock, subject to adjustment as set forth in the Merger Agreement and the form of pre-funded warrant.

The Exchange Ratio was calculated as 0.2074 shares of Cyclerion common stock for each share of Pre-Merger Korsana common stock (and 0.0002074 shares of Series B Preferred Stock for each share of Pre-Merger Korsana Series Seed Preferred Stock) on the Closing Date, which gives effect to a 1-for-7 reverse stock split of Cyclerion common stock immediately prior to the Merger. The par value per share and the number of authorized shares were not adjusted as a result of the Exchange Ratio. The shares of the Company's common stock underlying outstanding stock options, restricted stock awards, and other equity instruments were proportionately reduced and the respective exercise prices, if applicable, were proportionately increased in accordance with the terms of the agreements governing such securities. All references to common stock, options to purchase common stock, common stock share data, per share data, and related information contained in the condensed consolidated financial statements have been retrospectively adjusted to reflect the effect of the Exchange Ratio for all periods presented, unless otherwise specifically indicated or the context otherwise requires.

Immediately prior to the completion of the Merger, and in order to provide Korsana with additional capital for its development programs, Pre-Merger Korsana entered into a securities purchase agreement (the "Securities Purchase Agreement") with certain institutional and accredited investors, pursuant to which Pre-Merger Korsana issued and sold 140,516,578 shares of Pre-Merger Korsana common stock and 20,171,961 pre-funded warrants, exercisable for 20,171,961 shares of Pre-Merger Korsana common stock, at a purchase price of $ 2.3648 per share and $ 2.3647 per warrant, in each case before giving effect to the Exchange Ratio, for an aggregate purchase price of $ 380.0 million in a private placement (the "Pre-Closing Financing"). Entities affiliated with Fairmount and Venrock, both related parties of the Company, participated in the Pre-Closing Financing for aggregate purchase prices of $ 75.0 million and $ 60.0 million, respectively (see Note 13). At the Closing of the Merger, based on the exchange ratio, the Pre-Merger Korsana common stock and pre-funded warrants subscribed for were converted into the right to receive 29,143,142 shares of common stock and 4,183,665 pre-funded warrants. Shares of Pre-Merger Korsana common stock and pre-funded warrants to purchase shares of Korsana common stock issued pursuant to the Securities Purchase Agreement were converted into shares of Cyclerion common stock and pre-funded warrants to purchase shares of Cyclerion common stock at Closing per the Merger Agreement.

In connection with the Merger, the Company entered into a contingent value rights agreement (the "CVR Agreement"), pursuant to which certain legacy Cyclerion stockholders became entitled to receive contingent payments associated with the potential future monetization of certain legacy Cyclerion assets, including its equity investment in Tisento Therapeutics, Inc. (collectively, the "CVRs"). Payments under the CVRs are contingent upon the realization of proceeds from the underlying assets in accordance with the terms of the CVR Agreement. The Company determined that the CVRs represent a single freestanding derivative liability measured at fair value (see Note 2).

The Merger was accounted for as a reverse recapitalization in accordance with U.S. GAAP. Under this method of accounting, Pre-Merger Korsana was deemed to be the accounting acquirer for financial reporting purposes. This determination was primarily based on the fact that, immediately following the Merger: (i) Pre-Merger Korsana stockholders own a substantial majority of the voting rights in the combined company; (ii) Pre-Merger Korsana's largest stockholders retain the largest interest in the combined company; (iii)

KORSANA BIOSCIENCES, INC.

Note 2: Summary of Significant Accounting Policies 11 changes

The accounting policies of the Company are set forth in Note 2. Summary of Significant Accounting Policies to the consolidated financial statements contained in the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2025.

New Accounting Pronouncements

From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board ("FASB") or other standard setting bodies that are adopted by the Company as of the specified effective date. Except as discussed elsewhere in the notes to the interim condensed consolidated financial statements, the Company did not adopt any new accounting pronouncements during the six months ended June 30, 2026 that had a material effect on its condensed consolidated financial statements.

No other accounting standards known by the Company to be applicable to it that have been issued by the FASB or other standard-setting bodies and that do not require adoption until a future date are expected to have a material impact on the Company's condensed consolidated financial statements upon adoption.

The Company's significant accounting policies are disclosed in Note 2 to its audited financial statements as of and for the year ended December 31, 2025 and as of December 31, 2024 and for the period from November 8, 2024 (inception) to December 31, 2024 and the related notes included in Cyclerion's Registration Statement on Form S-4, declared effective on July 24, 2026. Since the date of those financial statements, there have been no changes to the Company's significant accounting policies except as noted below.

Cash, Cash Equivalents, and Restricted Cash

The following represents the Company's cash, cash equivalents, and restricted cash (in thousands):

Cash and cash equivalents

Total cash, cash equivalents, and restricted cash

The Company considers all short-term, highly liquid investments purchased with an original maturity of three months or less at the date of purchase to be cash equivalents. As of September 30, 2026 , the Company's restricted cash relates to a letter of credit for its office lease in Waltham, Massachusetts and is included in restricted cash in the Company's condensed consolidated balance sheet. The carrying value of the restricted cash approximates fair value.

KORSANA BIOSCIENCES, INC.

Note 5: Accrued Expenses and Other Current Liabilities 8 changes

1 unchanged paragraph

Employee compensation

Accrued expenses and other current liabilities

Accrued research and development (1)

Accrued professional and consulting (2)

Accrued employee compensation and benefits

Other accrued expenses

(1) Includes related party amount of $ 11,008 as of September 30, 2026 and $ 10,333 as of December 31, 2025 .

(2) Includes related party amount of $ 0 as of September 30, 2026 and $ 232 as of December 31, 2025 .

Note 11: Commitments and Contingencies 9 changes

Other Funding Commitments

In the normal course of business, the Company enters into contracts with clinical research organizations and other third parties for clinical and preclinical research studies and other services and products for operating purposes. These contracts are generally cancellable, with notice, at the Company's option and do not have any significant cancellation penalties.

Indemnification Obligations

On September 6, 2018, Cyclerion was incorporated in Massachusetts and its officers and directors are indemnified for certain events or occurrences while they are serving in such capacity.

The Company enters into certain agreements with other parties in the ordinary course of business that contain indemnification provisions. These typically include agreements with directors and officers, business partners, contractors, clinical sites and customers. Under these provisions, the Company generally indemnifies and holds harmless the indemnified party for losses suffered or incurred by the indemnified party as a result of the Company's activities. These indemnification provisions generally survive termination of the underlying agreements. The maximum potential amount of future payments the Company could be required to make under these indemnification provisions is unlimited. However, to date the Company has not incurred material costs to defend lawsuits or settle claims related to these indemnification provisions. As a result, the estimated fair value of these obligations is minimal. Accordingly, the Company did not have any liabilities recorded for these obligations as of June 30, 2026 and December 31, 2025 .

The Company maintains a defined-contribution plan under Section 401(k) of the Internal Revenue Code of 1986 (the "401(k) Plan"). The 401(k) Plan covers all employees who meet defined minimum age and service requirements and allows participants to defer a portion of their annual compensation on a pre-tax basis. Employer contributions to the 401(k) Plan may be made at the discretion of management. For the three and nine months ended September 30, 2026 , the Company has recorded $ 0.1 million and $ 0.2 million, respectively, related to 401(k) Plan employer contributions. For the three and nine months ended September 30, 2025 , the Company did no t record any expense related to 401(k) Plan employer contributions.

Indemnification Agreements

In the ordinary course of business, the Company may provide indemnification of varying scope and terms to vendors, lessors, business partners and other parties with respect to certain matters including, but not limited to, losses arising out of breach of such agreements or from intellectual property infringement claims made by third parties. In addition, the Company has entered into indemnification agreements with each of its directors and executive officers that will require the Company, among other things, to indemnify them against certain liabilities that may arise by reason of their status or service as directors or executive officers. The maximum potential amount of future payments the Company could be required to make under these indemnification agreements is, in many cases, unlimited.

KORSANA BIOSCIENCES, INC.

Legal proceedings 19 changes

We are not a party to any material legal proceedings at this time. From time to time, we may be subject to various legal proceedings and claims, which may have a material adverse effect on our financial position or results of operations.

From time to time, the Company may become involved in legal proceedings or other litigation relating to claims arising in the ordinary course of business. The Company accrues a liability for such matters when it is probable that future expenditures will be made and that such expenditures can be reasonably estimated. Significant judgment is required to determine both probability and estimated exposure amount. Legal fees and other costs associated with such proceedings are expensed as incurred. As of September 30, 2026 , the Company was not a party to any material legal proceedings or claims.

12. Net Loss per Share

Basic and diluted net loss per share attributable to common stockholders was calculated as follows (in thousands, except share and per share amounts):

Weighted Average Shares Outstanding

Loss Per Share - Basic and Diluted

Weighted Average Shares Outstanding

Loss Per Share - Basic and Diluted

Common Stock and pre-funded warrants

Series B Preferred Stock

(1) The weighted-average number of shares of as-converted Series B Preferred Shares used in the loss allocation was 1,025,849 and 348,190 for the three and nine months ended September 30, 2026 , respectively.

For the computation of basic net loss per share attributable to common stockholders, the amount of weighted-average common shares outstanding excludes all shares of unvested restricted common stock as such shares are not considered outstanding for accounting purposes until vested.

The Company's potential dilutive securities have been excluded from the computation of diluted net loss per share as the effect would be to reduce the net loss per share. Therefore, the weighted-average number of common shares outstanding used to calculate both basic and diluted net loss per share attributable to common stockholders is the same. The Company excluded potential common shares from the computation of diluted net loss per share attributable to common stockholders for the period presented because including them would have had an anti-dilutive effect:

Outstanding unvested restricted stock awards

Outstanding and issued warrant to Parasa

Outstanding and issued common stock options

13. Related Party Transactions

Fairmount, Venrock, Paragon, Paragon Laboratories and Parasa have been identified as related parties of Korsana and have engaged in material transactions with the Company for the nine months ended September 30, 2026. The Company entered into significant related

KORSANA BIOSCIENCES, INC.

MD&A 226 changes

Forward-Looking Information

The following discussion of our financial condition and results of operations should be read in conjunction with the unaudited condensed consolidated financial statements and the corresponding notes included in this Quarterly Report on Form 10-Q, as well as the audited condensed consolidated financial statements and notes thereto included in our Annual Report on Form 10-K for the fiscal year ended December 31, 2025. This discussion contains forward-looking statements that involve significant risks and uncertainties. As a result of many factors, such as those referenced or set forth under "Cautionary Note Regarding Forward-Looking Statements" and "Risk Factors" in Part II, Item 1A of this Quarterly Report on Form 10-Q, our actual results may differ materially from those anticipated in these forward-looking statements.

Overview and Recent Developments

We have focused on building a pipeline of innovative therapeutics to address serious neuropsychiatric disorders with significant unmet medical need. Our current strategic focus prior to the announcement of the Merger Agreement was centered on the development of a novel therapeutic approach for neuropsychiatric conditions, with the lead indication being treatment-resistant depression ("TRD"), which we believe represents a substantial clinical and commercial opportunity. Over the past year, we refined our strategic direction toward programs that combine established pharmacologic agents with enabling technologies designed to improve precision, reproducibility, and patient outcomes. As part of this strategy, Cyclerion has evaluated multiple opportunities and prioritized CYC-126, an individualized therapy for TRD as our foundational development program.

In September 2025, we entered into a license agreement with the Massachusetts Institute of Technology ("MIT") for intellectual property supporting this TRD program. In January 2026, we also entered into a collaboration and option-to-license agreement with Medsteer SAS ("Medsteer"), a developer of anesthesia delivery and monitoring technologies. This agreement provides Cyclerion with access to Medsteer's technical expertise, data assets, and intellectual property relating to technology-enabled drug delivery and physiological monitoring, and grants us the right, but not the obligation, to obtain additional rights under specified conditions. We intend to evaluate these capabilities as part of our broader development strategy for our TRD program. Given the substantial unmet medical need in TRD, the stage of clinical development, and the potential commercial opportunity, we believe this program has commercial promise. Due to cash limitations, we have suspended efforts advancing an integrated clinical, regulatory, and commercial strategy for this TRD program.

In parallel with the advancement of our neuropsychiatric strategy, Cyclerion continues to seek opportunities to monetize our legacy soluble guanylate cyclase ("sGC") stimulator assets, including potential collaborations, monetization opportunities, or other strategic transactions intended to maximize shareholder value.

The Merger Agreement

On April 1, 2026, Cyclerion entered into a Plan of Merger and Reorganization (as amended, the "Merger Agreement") with Korsana Biosciences, Inc. ("Korsana"), a privately held biotechnology company discovering and developing novel therapies to reduce the burden of neurodegenerative diseases, pursuant to which among other matters, and subject to the satisfaction or waiver of the conditions set forth in the Merger Agreement, Cariboos Merger Sub Corp., a Delaware corporation ("First Merger Sub"), will merge with and into Korsana, with Korsana continuing as a wholly owned subsidiary of Cyclerion and the surviving corporation of the merger (the "First Merger"), and Korsana will merge with and into Cariboos Merger Sub II, LLC, a Delaware limited liability company ("Second Merger Sub" and together with First Merger Sub, "Merger Subs"), with Second Merger Sub being the surviving entity of the merger (the "Second Merger" and, together with the First Merger, the "Merger"). After the completion of the Merger, Second Merger Sub will change its corporate name to "Korsana Biosciences Operating Company, LLC" and Cyclerion will change its name to "Korsana Biosciences, Inc." Cyclerion following the Merger is referred to herein as the "Combined Company." Cyclerion anticipates that the Merger will close in the third quarter of 2026, subject to certain closing conditions, along with the concurrent Korsana Pre-Closing Financing described below. Following the Merger, the current business of Korsana will become the primary business of Cyclerion.

At the closing of the First Merger (the "First Effective Time", and the date on which the closing of the Merger occurs, the "Closing Date"), upon the terms and subject to the conditions set forth in the Merger Agreement:

(i) each then-outstanding share of common stock, $0.0001 par value per share, of Korsana (the "Korsana Common Stock") and Series A Preferred Stock, $0.0001 par value per share of Korsana ("Korsana Series A Preferred Stock") (including shares of Korsana Common Stock issued in the Korsana Pre-Closing Financing described below), excluding any shares to be cancelled pursuant to the Merger Agreement and excluding dissenting shares, will be automatically converted solely into the right to receive a number of shares of Cyclerion common stock, no par value per share (the "Cyclerion Common Stock"), equal to the exchange ratio as described in the Merger Agreement (the "Exchange Ratio"); provided, that in the event the aggregate number of shares of Cyclerion Common Stock issuable to a holder of Korsana capital stock (when aggregated with all of the shares of the Cyclerion Common Stock outstanding then beneficially owned by such person and its affiliates (as calculated pursuant to Section 13(d) of the Securities Exchange Act of 1934, as amended, and Rule 13d-3 promulgated thereunder) immediately after giving effect to the issuance of the merger consideration) would result in the issuance of shares of Cyclerion Common Stock to a holder in excess of a specified percentage (initially set at a percentage up to 9.99%) of the total outstanding shares of Cyclerion Common Stock (such specified percentage, a "Beneficial Ownership Limitation"), then Cyclerion will issue to any such holder (x) shares of Cyclerion Common Stock up to such holder's Beneficial Ownership Limitation and (y) in lieu of any shares in excess of such holder's Beneficial Ownership Limitation, pre-funded warrants ("Cyclerion Pre-Funded Warrants") to purchase a number of shares of Cyclerion Common Stock upon exercise of such Cyclerion Pre-Funded Warrants equal to such excess shares; (ii) each then-outstanding share of Korsana Series Seed Preferred Stock, $0.0001 par value per share ("Korsana Series Seed Preferred Stock" and, together with the Korsana Series A Preferred Stock, the "Korsana Preferred Stock"), excluding any shares of Korsana Series Seed Preferred Stock to be cancelled pursuant to the Merger Agreement and any dissenting shares, will be converted into the right to receive a number of shares of Cyclerion Series B non-voting convertible preferred stock, no par value per share ("Cyclerion Series B Preferred Stock"), equal to the Exchange Ratio divided by 1,000; (iii) each then-outstanding option (a "Korsana Option") to purchase shares of Korsana Common Stock will be converted into and become an option to purchase shares of Cyclerion Common Stock on the existing terms and conditions (including with respect to vesting and accelerated vesting), subject to adjustment as set forth in the Merger Agreement; (iv) each then-outstanding restricted stock unit for shares of Korsana Common Stock will be converted into and become a restricted stock unit for shares of Cyclerion Common Stock on the existing terms and conditions (including with respect to vesting and accelerated vesting), subject to adjustment as set forth in the Merger Agreement; and (v) each then-outstanding warrant to purchase shares of Korsana Common Stock will be converted into a warrant to purchase shares of Cyclerion Common Stock on the existing terms and conditions, subject to adjustment as set forth in the Merger Agreement.

Each share of Cyclerion Common Stock and Cyclerion Series A Preferred Stock that is issued and outstanding at the First Effective Time will remain issued and outstanding and such shares, subject to the proposed reverse stock split, will be unaffected by the Merger. Prior to the First Effective Time, the Cyclerion board of directors will accelerate the vesting of all options to purchase shares of Cyclerion Common Stock ("Cyclerion Options") and all restricted stock awards ("Cyclerion RSAs"). Each outstanding Cyclerion Option with an exercise price per share equal to or less than the volume weighted average closing trading price of a share of Cyclerion Common Stock on The Nasdaq Stock Market LLC ("Nasdaq") for the five consecutive trading days ending three trading days prior to the Calculation Date (as defined in the Merger Agreement), as reported by Bloomberg L.P. (the "Cyclerion Closing Price"), will be cancelled at the First Effective Time and such holder thereof will receive an amount in cash, without interest, less any applicable tax withholding, equal to the product obtained by multiplying the excess of the Cyclerion Closing Price over the exercise price per share of the Cyclerion Common Stock underlying such Cyclerion Option by the number of shares of the Cyclerion Common Stock underlying such Cyclerion Option. Each Cyclerion Option with an exercise price greater than the Cyclerion Closing Price will be cancelled for no consideration. The vesting of each Cyclerion RSA will be accelerated in full.

Based on Cyclerion's and Korsana's capitalization as of June 30, 2026 and assuming Cyclerion's net cash as of closing being equal to $(2.5) million, each share of Korsana Common Stock and Korsana Series A Preferred Stock is currently estimated to be entitled to receive approximately 1.4735 shares of Cyclerion Common Stock. Each share of Korsana Series Seed Preferred Stock will be converted into the right to receive a number of shares of Cyclerion Series B Preferred Stock, equal to the Exchange Ratio divided by 1,000. The estimated Exchange Ratio does not give effect to the proposed Cyclerion reverse stock split and is subject to adjustment based on Cyclerion's estimated net cash at the closing of the First Merger.

In connection with the Merger, on April 1, 2026, Korsana entered into a securities purchase agreement (the "Securities Purchase Agreement") with certain institutional and accredited investors for the purchase of shares of Korsana Common Stock and Pre-Funded Warrants to purchase shares of Korsana Common Stock (the "Korsana Pre-Funded Warrants") for an aggregate purchase price of approximately $380.0 million, immediately prior to the closing of the Merger (referred to herein as the "Korsana Pre-Closing Financing"). The shares of Korsana Common Stock and Korsana Pre-Funded Warrants that are issued in the Korsana Pre-Closing Financing will be converted into the right to receive a number of shares of Cyclerion Common Stock and Cyclerion Pre-Funded Warrants, respectively, equal to the Exchange Ratio. Korsana and the investors participating in the Korsana Pre-Closing Financing have also agreed to enter into a registration rights agreement at the closing of the Korsana Pre-Closing Financing, pursuant to which, among other things, the Combined Company will agree to provide for the registration and resale of certain shares of Korsana Common Stock that are held by the investors participating in the Korsana Pre-Closing Financing from time to time pursuant to Rule 415 under the Securities Act.

Based on its current operating plan, Cyclerion expects that its current cash and cash equivalents will fund its operating expenses until the closing of the contemplated Merger, which is subject to approval by its shareholders and the shareholders of Korsana and other customary closing conditions; however, Cyclerion has based this estimate on assumptions that may prove to be wrong, and Cyclerion could use its capital resources sooner than Cyclerion expects.

Cyclerion CVR Agreement

At or prior to the first merger, Cyclerion will enter into a Contingent Value Rights Agreement (the "CVR Agreement") with a designated rights agent (the "Rights Agent"), pursuant to which Cyclerion's pre-merger shareholders will receive one contingent value right (each a "CVR") for each outstanding share of Cyclerion Common Stock and Cyclerion Series A Preferred Stock held by such shareholder on such date. Each CVR will represent the contractual right to receive certain net proceeds, if any, derived from any consideration that is paid to Cyclerion as a result of the disposition of Cyclerion's pre-Merger legacy assets, net of any indemnity obligations, transaction costs and certain other expenses, during the period beginning on the date of the closing of the merger and ending (i) with respect to the sale, transfer, license or other disposition of all pre-merger legacy assets other than those pre-merger legacy assets described in the following clauses (ii) and (iii), upon the second (2nd) anniversary of the Closing Date, (ii) with respect to Cyclerion's right to receive payments under that certain License Agreement, dated June 3, 2021, between Cyclerion and Akebia Therapeutics, Inc. (the "Akebia License Agreement"), the earlier of (A) the fifteenth (15th) anniversary of the date of entry into the CVR Agreement and (B) the expiration or earlier termination by Akebia Therapeutics, Inc. of the Akebia License Agreement pursuant to its terms, and (iii) with respect to the sale, transfer or other disposition of the equity interests of Tisento that were acquired by Cyclerion pursuant to that certain Asset Purchase Agreement, dated May 13, 2023, by and among Cyclerion, Tisento and JW Cycle, Inc., the earliest of (A) nine (9) months following the date of the consummation of Tisento's initial public offering pursuant to a registration statement filed with, and declared effective by, the Securities and Exchange Commission pursuant to the Securities Act, (B) the sale of Tisento, and (C) the seventh (7th) anniversary of the Closing Date.

The contingent payments under the CVR Agreement, if they become payable, will become payable to the Rights Agent for subsequent distribution to the holders of the CVRs. In the event that no such proceeds are received, holders of the CVRs will not receive any payment pursuant to the CVR Agreement. There can be no assurance that any holders of CVRs will receive any payments with respect thereto.

Research and Development Expense. Research and development expenses are incurred in connection with the discovery and development of our product candidates. These expenses consist primarily of the following costs: compensation, benefits and other employee-related expenses, research and development-related facilities, third-party contracts relating to manufacturing, nonclinical studies, clinical trial activities. All research and development expenses are charged to operations as incurred.

Praliciguat is an orally administered, once-daily systemic sGC stimulator. On June 3, 2021, we entered into a license agreement with Akebia relating to the exclusive worldwide license to Akebia of our rights to the development, manufacture, medical affairs and commercialization of pharmaceutical products containing praliciguat and other related products and forms thereof enumerated in such agreement. In 2021, Akebia paid a $3.0 million upfront payment to us upon signing of the license agreement.

On December 13, 2024, we announced that Cyclerion and Akebia re-negotiated a mutually beneficial amendment to Akebia's exclusive license agreement for praliciguat. Under this new license amendment, we received $1.75 million in amendment payments, of which $1.25 million was paid in December 2024 and an additional payment of $0.5 million was paid in September 2025. In addition, Akebia is responsible for all intellectual property expenses associated with praliciguat at an earlier date than as originally agreed between the parties. On December 1, 2025, Akebia publicly announced that it has recently initiated Phase 2 clinical trials for the treatment of focal segmental glomerulosclerosis ("FSGS") using praliciguat. Pursuant to the terms of amendment, upon initiation (defined as first patient dosed) of a Phase 2 clinical trial in the U.S. for a product, a $1.0 million development milestone payment would be due to us and the payment was received in February 2026. We are eligible to receive additional milestone cash payments of up to approximately $557.5 million in total related to potential future development, regulatory, and commercialization milestone payments for praliciguat. In exchange for a reduction in certain development milestone payments, we are eligible to receive certain higher-tiered sales-based royalties ranging from mid-single-digits to twenty percent.

In September 2025, we entered in a Material Purchase Agreement (the "Purchase Agreement") with Akebia relating to purchase additional development materials (the "Additional Development Materials") by Akebia for Akebia's use pursuant to the license agreement. Akebia paid $0.8 million to us for the purchase during the year ended December 31, 2025 and the Additional Development Materials were delivered to Akebia as of December 31, 2025 and we recognized revenue of $0.8 million during the year ended December 31, 2025.

Olinciguat is a Phase 2, orally administered, once-daily, vascular sGC stimulator. On July 22, 2024, we entered into an Option to License Agreement (the "Option Agreement") with a third party (the "Optionee"), pursuant to which the Optionee had an option (the "Option") to enter into an exclusive license to olinciguat for human therapeutics, subject to certain carveouts. Under the terms of the Option Agreement, the Optionee paid us an Option fee of $150,000 in August 2024 and subsequent fees totaling $80,000 to extend the term of the Option Agreement. The Optionee originally could exercise the Option on or before March 20, 2025, which option period was ultimately extended through August 22, 2025. Thereafter, the parties had an additional 60 days to negotiate the terms of a definitive license agreement. The parties were unable to agree upon the terms of a license agreement and we were provided notice on October 23, 2025 that it was terminating the Option Agreement. We are currently exploring potential license opportunities for olinciguat.

Zagociguat and CY3018 are orally administered CNS-penetrant sGC stimulators. On July 28, 2023, Tisento purchased zagociguat and CY3018 in exchange for $8.0 million in cash consideration, $2.4 million as reimbursement for certain operating expenses related to zagociguat and CY3018 for the period between signing and closing of the transaction, and 10% of all of Tisento Parent's outstanding equity securities at the time of closing. Research and development expenses decreased significantly after July 28, 2023, due to sale of the Transferred Assets which resulted in a reduction of research and development efforts.

On January 27, 2025, Tisento announced that the first patient had been dosed in its global Phase 2b PRIZM study. The study is investigating the impact of once-daily oral zagociguat treatment on fatigue, cognitive impairment, and other key aspects of the rare mitochondrial disease MELAS (Mitochondrial Encephalomyopathy, Lactic Acidosis, and Stroke-like Episodes). On June 17, 2025, Tisento announced that the U.S. Food and Drug Administration (FDA) has granted Fast Track designation to zagociguat for the treatment of MELAS.

PRIZM – a Phase 2b Randomized, Placebo-Controlled Trial Investigating Zagociguat in MELAS – is evaluating the efficacy and safety of oral zagociguat 15 mg or 30 mg compared to placebo when administered once-daily for 12 weeks in participants with genetically and phenotypically defined MELAS. The PRIZM study has a crossover design, with two 12-week treatment periods separated by a 4-week washout period. All participants will receive zagociguat during one of the 12-week periods and placebo during the other. Participants who complete the study may be eligible for an open-label extension study. PRIZM is a global study with plans to enroll approximately 44 participants at mitochondrial disease centers of excellence in the U.S., Italy, Germany, United Kingdom, Australia, and Canada. Tisento announced its first patient was dosed in the study in January 2025. In August 2025, Tisento announced that the first patient was enrolled in Tisento's open-label extension study in MELAS and in January 2026, Tisento announced that it completed enrollment in PRIZM. Further information regarding the study is available at ClinicalTrials.gov (NCT06402123).

On September 19, 2025, Cyclerion and the Massachusetts Institute of Technology ("MIT") entered into a Patent License Agreement (the "MIT License Agreement") pursuant to which MIT granted to us an exclusive worldwide license to develop and commercialize products using certain technology for the treatment of neuropsychiatric disorders, such as depression, in humans. Under the MIT License Agreement, we paid a nominal upfront license fee and patent reimbursement fee. Thereafter, we are also required to pay MIT a nominal annual license maintenance fee. This annual license maintenance fee is nonrefundable; however, the license maintenance fee may be credited to royalties earned during the same calendar year, if any. License maintenance fees paid in excess of royalties due in such calendar year shall not be creditable to amounts due for future years. Under the terms of the MIT License Agreement, MIT will be eligible to receive up to $4.4 million upon the achievement of certain development, regulatory and sales milestone payments. MIT will also receive tiered royalties in a range of percentages in the low single digits based on future net sales of licensed products as set forth in the MIT License Agreement. Further, we are required to pay MIT varying percentages of income received as consideration for any sublicenses granted pursuant to the MIT License Agreement depending on the circumstances of the sublicense and the development milestones of sublicensed products. The term of the MIT License Agreement will expire in its entirety upon the expiration of certain patent rights for the licensed patents, unless earlier terminated by the parties in accordance with the terms of the MIT License Agreement. We recorded research and development expense of $0.1 million for the year ended December 31, 2025, which consisted of upfront fees, patent reimbursement fees and transaction costs related to the license.

On January 3, 2026, we and Medsteer SAS ("Medsteer") entered into a Collaboration and Option Agreement (the "Collaboration Agreement") pursuant to which Medsteer granted to us (i) a non-exclusive, worldwide, royalty-free, sublicensable license of certain of Medsteer's technology, software and intellectual property to develop an anesthetic delivery system with Medsteer and (ii) an exclusive option (the "Option"), exercisable at our sole discretion, to obtain an exclusive, worldwide, royalty-bearing, sublicensable license of certain of Medsteer's technology, software and intellectual property to develop or commercialize licensed products in any field of use except for sedation regulation for patients undergoing major surgery, in multi-bed or intensive unit wards, or in the context of medical transport. We may exercise the Option at any time until the earlier of the second anniversary of the effective date of the Collaboration Agreement, which period may be extended for an additional two years at our option and upon payment of a nominal fee or by mutual agreement of us and Medsteer.

Under the terms of the Collaboration Agreement, the Company will pay to Medsteer a nominal upfront payment, a payment upon exercise of the Option, and Medsteer will be eligible to receive up to $3.7 million upon the achievement of certain development, regulatory and sales milestone payments. Medsteer will also receive an annual royalty payment and royalties in a percentage in the low single digits based on future net sales of licensed products, subject to certain adjustments as set forth in the Collaboration Agreement.

We continue to evaluate other activities aimed at enhancing shareholder value, which may potentially include collaborations, licenses, mergers, acquisitions, and/or other targeted investments.

The following table summarizes our research and development expenses, employee and facility related costs allocated to research and development expense, and discovery and pre-clinical phase programs, for the three and six months ended June 30, 2026 and 2025. The product pipeline expenses relate primarily to external costs associated with nonclinical studies.

Personnel and related internal costs

Total research and development expenses

Securing regulatory approvals for new drugs is a lengthy and costly process. Any failure by us or our partners to obtain, or any delay in obtaining, regulatory approvals would materially adversely affect our product candidate development efforts and our business overall.

Given the inherent uncertainties of pharmaceutical product development, we cannot estimate with any degree of certainty how our programs will evolve, and therefore the amount of time or money that would be required to obtain regulatory approval to market them. As a result of these uncertainties surrounding the timing and outcome of any approvals, we are currently unable to estimate precisely when, if ever, our discovery and development candidates will be approved.

If we continue to progress the development of our product candidates, the successful development of any current or potential future product candidates is highly uncertain and subject to a number of risks.

We are unable to determine the duration and costs to complete current or future nonclinical and clinical stages of any current or potential future product candidates, including as licensed to third parties, or when, or to what extent, we may generate revenues from the commercialization and sale of any current or potential future product candidates. Development timelines, probability of success and development costs vary widely. We anticipate that we will make determinations as to which additional programs to pursue and how much funding to direct to each program on an ongoing basis in response to the data from the studies of each product candidate, the competitive landscape and ongoing assessments of such product candidate's commercial potential.

General and Administrative Expense. General and administrative expenses consist primarily of compensation, benefits and other employee and non-employee related expenses for personnel in our administrative, finance, legal, information technology, business development, and human resource functions. Other costs include the legal costs of pursuing patent protection of our intellectual property, insurance costs and professional fees for accounting and legal services. We record all general and administrative expenses as incurred.

Critical Accounting Policies and Estimates

Our discussion and analysis of our financial condition and results of operations is based upon our consolidated financial statements prepared in accordance with GAAP. The preparation of these financial statements requires us to make certain estimates and assumptions that may affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements, and the amounts of expenses during the reported periods. We base our estimates on our historical experience and on various other assumptions that are believed to be reasonable, the results of which form the basis for making judgments about the carrying values of assets and liabilities. Actual results may differ materially from our estimates under different assumptions or conditions. Changes in estimates are reflected in reported results in the period in which they become known.

We believe that our application of accounting policies requires significant judgments and estimates on the part of management and is the most critical to aid in fully understanding and evaluating our reported financial results. Our significant accounting policies are more fully described in Note 2, Summary of Significant Accounting Policies , of the consolidated financial statements elsewhere in Annual Report on Form 10-K for the fiscal year ended December 31, 2025.

All research and development expenses are expensed as incurred. We defer and capitalize nonrefundable advance payments we make for research and development activities until the related goods are received or the related services are performed. A discussion of our critical accounting policies and estimates may be found in our Annual Report on Form 10-K for the fiscal year ended December 31, 2025 in Item 7, Management's Discussion and Analysis of Financial Condition and Results of Operations under the heading Critical Accounting Policies and Estimates.

The revenue and expenses reflected in the consolidated financial statements may not be indicative of revenue and expenses that will be incurred by us in the future. The following discussion summarizes the key factors we believe are necessary for an understanding of our consolidated financial statements.

(dollars in thousands)

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Revenue from option agreement

You should read the following discussion and analysis of our financial condition and results of operations in conjunction with the unaudited condensed consolidated financial statements and the related notes included in Part I - Item 1 of this Quarterly Report on Form 10-Q for the quarterly period ended September 30, 2026 (this "Quarterly Report"). This report contains forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended (the "Securities Act") and Section 21E of the Securities Exchange Act of 1934, as amended (the "Exchange Act") that reflect our current plans, forecasts, estimates and beliefs and involve risks and uncertainties. These forward-looking statements include, but are not limited to, express or implied statements regarding the Company's expectations, hopes, beliefs, intentions or strategies regarding the future. In some cases, you can identify forward-looking statements by terminology such as "may," "might," "will," "could," "should," "expects," "intends," "plans," "anticipates," "believes," "estimates," "predicts," "projects," "seeks," "target," "endeavor," "possible," "potential," "continue," "contemplate" or the negative of these terms or other comparable terminology, but the absence of these words does not mean that a statement is not forward-looking. These forward-looking statements are based on current expectations and beliefs concerning future developments and their potential effects. There can be no assurance that future developments affecting the Company will be those that have been anticipated. These forward-looking statements involve a number of risks, uncertainties (some of which are beyond the Company's control) or other assumptions that may cause actual results or performance to be materially different from those expressed or implied by these forward-looking statements. Our historical results are not necessarily indicative of the results that may be expected for any period in the future. Our actual results, outcomes and the timing of events could differ materially from those discussed in the forward-looking statements. Forward-looking statements are not historical facts, reflect our current views with respect to future events, and apply only as of the date made. We do not intend, and undertake no obligation, to update these forward-looking statements, except as required by law. References to "we," "us," "our," "Korsana" or "the Company" refer to Korsana Biosciences, Inc. and its consolidated subsidiaries after the Merger, unless context otherwise requires.

We are a biopharmaceutical company developing therapeutics to treat neurodegenerative diseases beginning with Alzheimer's disease ("AD"). Our lead product candidate, KRSA-028, is an anti-amyloid beta ("Aβ") antibody that combines the proprietary Therapeutic Targeting ("THETA ™ ") platform with clinical and regulatory learnings from other anti-Aβ products that have achieved regulatory approval or are in late-stage clinical trials. KRSA-028 was designed to build upon the success of these prior products while addressing shortcomings that limit their clinical and commercial success, such as the ability to penetrate the brain. We believe that KRSA-028 has the potential to rapidly clear amyloid plaques resulting in meaningful impacts on clinical symptoms in AD patients, and to do so while avoiding adverse effects associated with the specific designs of prior products. After we complete clinical trial-enabling activities, we intend to submit a Clinical Trial Notification ("CTN") in Australia or a Clinical Trial Application ("CTA") in New Zealand by the end of 2026 and an Investigational New Drug ("IND") application in the United States in the first quarter of 2027. Pharmacokinetic data in healthy volunteers is anticipated by mid-year 2027 and interim proof-of-concept data in Alzheimer's disease patients is anticipated by year-end 2027 or the first quarter of 2028. The outcome of preclinical studies and early-stage clinical trials may not be predictive of the success of later clinical trials.

AD is a progressive and devastating neurodegenerative disease that slowly destroys cognition and leads to progressive impairment in patients' ability to conduct activities of daily living. Prevalence increases with age; up to one-third of people over age 85 have symptoms. There are seven million people suffering from AD in the United States, a number that is expected to double by 2050 due to an aging population. AD is the seventh-leading cause of death in the United States with an estimated 500,000 deaths every year.

Until recently, approved treatments for AD addressed only symptoms and had no impact on the course of the disease. That situation changed after the approval of antibody-based therapeutics that targeted Ab. Clinical trials of these therapeutics have provided clear evidence that antibody-mediated depletion of Aβ in the brain correlates with a reduction in the rate of cognitive decline in symptomatic AD.

KRSA-028 was designed using clinical and regulatory learnings from these pioneering antibody-based therapeutics, together with our proprietary combination of antibody engineering technologies, with the goal of improving clinical efficacy and safety profiles. KRSA-028 targets what is believed to be the most clinically relevant form of Aβ and is designed to improve brain uptake while reducing effects on reticulocytes. It was also designed with physicochemical properties and stability intended to enable potent anti-Aβ activity to the brain via subcutaneous injections. Key features of KRSA-028's design include:

• Incorporating a proprietary transferrin receptor, or TfR, based shuttle designed to potentially improve delivery to the brain, which we believe may also help reduce or avoid the treatment-related complications known as amyloid-related imaging abnormalities, or ARIA, associated with the two approved disease-modifying therapies

• Targeting 3-pyroglutamate Ab, or 3pE-Ab, a form of Aβ that is enriched in amyloid plaques that is believed to contribute to plaque formation in AD

• Incorporating Fc domain modifications designed to potentially improve half-life and reduce the potential for hematologic adverse events seen with other antibodies that incorporate TfR-based shuttles, while potentially preserving antibody-mediated immune function believed to contribute to amyloid plaque clearance

• Enabling subcutaneous formulation through potentially favorable solubility, viscosity, and stability characteristics

The proprietary THETA technology used to create KRSA-028 combines the benefits of TfR-mediated shuttling to the brain with Fc modifications to extend half-life and spare reticulocytes from destruction shown to be caused by third-party TfR-shuttled investigational products. The THETA technology was designed to retain phagocytic capacity, the mechanism by which the two approved disease-modifying products are thought to clear amyloid plaques from the brain. We believe that the THETA platform will lead to meaningful improvements in the ability to deliver therapeutic modalities, such as antibodies, to the brain, while minimizing the frequency of adverse events associated with other TfR-based shuttle systems.

In addition to KRSA-028, we are advancing a pipeline of innovative therapies for neurodegenerative diseases. We anticipate disclosing details on our next product candidate in 2027.

Since our inception in November 2024, we have devoted substantially all of our resources to raising capital, organizing and staffing the company, business and scientific planning, conducting discovery and research activities, establishing arrangements with third parties, and providing general and administrative support for these operations. We do not have any programs approved for sale and have not generated any revenue from product sales. To date, we have funded our operations primarily through proceeds from the issuance of convertible preferred stock and our $380.0 million proceeds from the Pre-Closing Financing (as defined and further described in "Recent Developments" below).

We have incurred operating losses since inception. Our ability to generate product revenue sufficient to achieve profitability will depend heavily on the successful development and eventual commercialization of any programs we may develop. We incurred net losses of $46.4 million and $77.3 million for the three and nine months ended September 30, 2026. As of September 30, 2026, we had an accumulated deficit of $113.0 million.

As of September 30, 2026, we had cash and cash equivalents of $456.2 million. We expect that our existing cash and cash equivalents will be sufficient to fund our operating expenses and capital expenditures into 2029. We expect to continue to incur substantial losses for the foreseeable future, and our transition to profitability will depend upon successful development, approval and commercialization of our product candidates and upon achievement of sufficient revenues to support our cost structure.

On September 8, 2026, we consummated the previously announced transaction (the "Closing") pursuant to that certain Agreement and Plan of Merger and Reorganization, dated as of April 1, 2026, which agreement was subsequently amended on April 17, 2026 (as amended, the "Merger Agreement"), by and among Pre-Merger Korsana, Cyclerion, Cariboos Merger Sub Corp. ("First Merger Sub"), and Cariboos Merger Sub II, LLC ("Second Merger Sub"). First Merger Sub merged with and into Pre-Merger Korsana, with Pre-Merger Korsana continuing as a wholly owned subsidiary of Cyclerion and the surviving corporation (the "First Merger"), and Pre-Merger Korsana merged with and into Second Merger Sub, with Second Merger Sub being the surviving entity of the merger (the "Second Merger", and together with the First Merger, the "Merger"). After completion of the Merger, Second Merger Sub changed its name to "Korsana Biosciences Operating Company, LLC" and Cyclerion changed its name to "Korsana Biosciences, Inc." We are led by Pre-Merger Korsana's management team and remain focused on discovering and developing novel therapies designed to reduce the burden of neurodegenerative diseases, starting with Alzheimer's disease.

Immediately prior to the Closing of the Merger, Cyclerion effected a one-for-seven reverse stock split of its common stock. At the effective time of the Merger, outstanding shares of Pre-Merger Korsana common stock, including shares issued in connection with the Pre-Closing Financing, were exchanged for shares of Cyclerion common stock based on the Exchange Ratio. Pre-Merger Korsana Series Seed Preferred Stock was exchanged for Series B Non-Voting Convertible Preferred Stock, while Series A Preferred Stock was exchanged for common stock or, to the extent issuance would exceed a holder's beneficial ownership limitation of up to 9.99%, pre-funded warrants to purchase common stock. Outstanding stock options, restricted stock awards and warrants of Pre-Merger Korsana were also assumed or converted, as applicable, in accordance with the Merger Agreement. Additional information regarding the Merger, including the Exchange Ratio and treatment of outstanding equity instruments, is included in Note 1 to the unaudited condensed consolidated financial statements.

The Merger was accounted for as a reverse recapitalization in accordance with U.S. GAAP. Under this method of accounting, Pre-Merger Korsana was deemed to be the accounting acquirer for financial reporting purposes. This determination was primarily based on the fact that, immediately following the Merger: (i) Pre-Merger Korsana stockholders own a substantial majority of the voting rights in the combined company; (ii) Pre-Merger Korsana's largest stockholders retain the largest interest in the combined company; (iii) Pre-Merger Korsana designated a majority of the initial members of the board of directors of the combined company; and (iv) Pre-Merger Korsana's executive management team became the management team of the combined company. Accordingly, for accounting purposes: (i) the Merger was treated as the equivalent of Pre-Merger Korsana issuing stock to acquire the net assets of Cyclerion; and (ii) the reported historical operating results of the combined company prior to the Merger are those of Pre-Merger Korsana. Additional information regarding the Merger is included in Note 3 to the condensed consolidated financial statements included in Part I – Item 1 of this Quarterly Report.

Pre-Closing Financing

Immediately prior to the completion of the Merger, and in order to provide us with additional capital for our development programs, Pre-Merger Korsana entered into the Securities Purchase Agreement with certain institutional and accredited investors, pursuant to which Pre-Merger Korsana issued and sold 140,516,578 shares of Pre-Merger Korsana common stock and 20,171,961 pre-funded warrants, exercisable for 20,171,961 shares of Pre-Merger Korsana common stock, at a purchase price of $2.3648 per share and $2.3647 per warrant, in each case before giving effect to the Exchange Ratio, for an aggregate purchase price of $380.0 million in a private placement (the "Pre-Closing Financing"). At the Closing of the Merger, based on the Exchange Ratio, the Pre-Merger Korsana common stock and pre-funded warrants subscribed for were converted into the right to receive 29,143,142 shares of common stock and 4,183,665 pre-funded warrants. Shares of Pre-Merger Korsana common stock and pre-funded warrants to purchase shares of Korsana common stock issued pursuant to the Securities Purchase Agreement were converted into shares of Cyclerion common stock and pre-funded warrants to purchase shares of Cyclerion common stock at Closing per the Merger Agreement.

Immediately prior to the consummation of the Merger, Cyclerion effected a one-for-seven reverse stock split of its common stock, which became legally effective on September 8, 2026 (the "Reverse Stock Split"). The Company's common stock commenced trading on a post-Reverse Stock Split and post-Merger basis on September 9, 2026. In connection with the Merger, the Exchange Ratio was determined to be 0.2074 shares of Cyclerion common stock for each share of Pre-Merger Korsana common stock, which gives effect to the Reverse Stock Split. All references to common stock, options to purchase common stock, common stock share data, per share data, and related information in the condensed consolidated financial statements have been retrospectively adjusted to reflect the Exchange Ratio for all periods presented, unless otherwise indicated.

Proposed Redomestication

On October 15, 2026, we filed a definitive proxy statement (the "Proxy Statement") for a special meeting of our shareholders to be held on November 13, 2026 (the "Special Meeting") to approve the redomestication of the Company from the Commonwealth of Massachusetts to the Cayman Islands (the "Redomestication"). The Redomestication is conditioned on the approval of the Redomestication Proposal (as defined in the Proxy Statement) at the Special Meeting and will not be effected unless approved. See Part II – Item 1A. "Risk Factors – Risks Related to the Proposed Redomestication."

Impact of General Economic Risk Factors on Our Operations

Uncertainty in the global economy presents significant risks to our business. We are subject to continuing risks and uncertainties in connection with the current macroeconomic environment, including increases in inflation, fluctuating interest rates, new or increased tariffs and other barriers to trade, changes to fiscal and monetary policy or government budget dynamics (particularly in the pharmaceutical and biotech areas), bank failures, geopolitical factors, including the ongoing conflicts between Russia and Ukraine and in the Middle East and the responses thereto, and supply chain disruptions. While we are closely monitoring the impact of the current macroeconomic and geopolitical conditions on all aspects of our business, including the impacts on participants in any future clinical trials and our employees, suppliers, vendors and business partners and our future access to capital, the ultimate extent of the impact on our business remains highly uncertain and will depend on future developments and factors that continue to evolve. Most of these developments and factors are outside our control and could exist for an extended period of time. We will continue to evaluate the nature and extent of the potential impacts to our business, results of operations, liquidity and capital resources. For additional information, see Part II, Item 1A of the Quarterly Report titled "Risk Factors."

Components of Results of Operations

To date, we have not generated revenue from any sources, including product sales, and do not expect to generate any revenue from the sale of products in the foreseeable future. If our development efforts for our product candidates are successful and result in regulatory approval, we may generate revenue in the future from product sales or payments from future collaboration or license agreements that we may enter into with third parties, or any combination thereof. We cannot predict if, when, or to what extent we will generate revenue from the commercialization and sale of our product candidates. We may never succeed in obtaining regulatory approval for any of our product candidates.

Our operating expenses consist of (i) research and development expenses and (ii) general and administrative expenses.

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Research and development expenses consist primarily of costs incurred in connection with the research and development of our programs. These expenses include:

• costs of funding research performed by third parties, including Paragon Therapeutics, Inc. ("Paragon") and Paragon Laboratories, Inc. ("Paragon Laboratories"), that conduct research and development activities on our behalf and services rendered under the Antibody Discovery and Option Agreement (the "Paragon ADOA"), Paragon Platform Option Agreement (the "Paragon POA"), and Paragon Research Letter Agreement ("Paragon Research Letter Agreement") for research programs, the Aβ program and undisclosed programs;

• expenses incurred in connection with continuing our current research programs and discovery-phase development of any programs we may identify, including under future agreements with third parties, such as consultants and contractors; and

• personnel-related expenses, including recruiting costs, salaries, bonuses, benefits and equity-based compensation expense.

We expense research and development costs as incurred. For the three and nine months ended September 30, 2026, we recognized $20.3 million and $35.5 million, respectively, of expenses in connection with services provided by Paragon under the Paragon ADOA in our condensed consolidated statements of operations and comprehensive loss. For the three and nine months ended September 30, 2026, we recognized $2.0 million and $3.0 million, respectively, of expenses in connection with services provided by Paragon Laboratories under the Paragon Research Letter Agreement. For the three and nine months ended September 30, 2026, we recognized $1.4 million of expenses in connection with services provided by Paragon under the Paragon POA. For both the three and nine months ended September 30, 2025, we recognized $20.3 million of expenses in connection with services provided by Paragon for the Aβ program and stock compensation.

We expect that our research and development expenses will increase substantially for the foreseeable future as we continue to invest in research and development activities related to the continued development of our programs, developing any future programs, including investments in manufacturing, as we advance any program we may identify and commence and conduct clinical trials.

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Total cost and expenses

General and administrative expenses consist primarily of personnel-related expenses, including recruiting costs, salaries, bonuses, benefits and equity-based compensation, for individuals in our executive, finance, legal, operations, human resources, business development and other administrative functions. Other significant general and administrative expenses include legal fees relating to corporate matters and patent-related activities, insurance costs, information technology, and professional and consulting fees associated with accounting, audit, tax and investor and public relations.

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and 146 more changes in the filing

Market risk 1 change

We are a smaller reporting company, as defined by Rule 12b-2 of under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), and in Item 10(f)(1) of Regulation S-K, and are not required to provide the information required under this item.

Controls and procedures 3 changes

Management's Evaluation of Disclosure Controls and Procedures

The term We maintain disclosure controls and procedures as defined in Rules 13a-15(e) and 15d-15(e) under the Exchange Act refers to controls and procedures that are designed to ensure that information required to be disclosed by a company us in the reports that it files we file or submits submit under the Exchange Act is recorded, processed, summarized, and reported within the time periods specified in the SEC's rules and forms. Our disclosure controls and procedures include, without limitation, controls and procedures designed to ensure that information required to be disclosed by a company us in the reports that it files or submits we file under the Exchange Act is accumulated and communicated to the company's our management, including its our principal executive officer and principal financial officers, or persons performing similar functions, officer, as appropriate to allow timely decisions regarding required disclosure. Because there are inherent limitations In all control systems, a control system, designing and evaluating the disclosure controls and procedures, management recognizes that any controls and procedures, no matter how well conceived designed and operated, can provide only reasonable as opposed to absolute, assurance that the objectives of achieving the desired control system are met. These inherent limitations include the realities that judgments in decision-making can be faulty, and that breakdowns can occur because of simple error or mistake. Additionally, controls can be circumvented by the individual acts of some persons, objectives. As required by collusion of two or more people, Rule 13a-15(b) or Rule 15d-15(b) promulgated by management override of the control. Further, SEC under the design of a control system must reflect Exchange Act, we carried out an evaluation, under the fact that there are resource constraints, supervision and the benefits of controls must be considered relative to their costs. Our management, with the participation of our chief management, including our principal executive officer and chief principal financial officer, evaluated of the effectiveness of the design and operation of our disclosure controls and procedures as of the end of the period covered by this Quarterly Report. Based on that evaluation, the foregoing, our chief principal executive officer and chief principal financial officer concluded that our disclosure controls and procedures were effective at the reasonable assurance level, as of the end of the period covered by this Quarterly Report However, our management does not expect that our disclosure controls and procedures or our internal control over financial reporting will prevent all errors and all fraud. at the reasonable assurance level.

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There were no changes in our internal control over financial reporting (as defined in Rules 13a-15(f) and 15d-15(f) under the Exchange Act) that occurred during the period covered by this Quarterly Report on Form 10-Q which quarter ended September 30, 2026, that have materially affected, or are reasonably likely to materially affect, our internal control over financial reporting.

Risk factors 352 changes

You should carefully review and consider the information regarding certain factors which could materially affect our business, financial condition or future results set forth under the heading "Risk Factors" in Part I, Item 1A of our Annual Report on Form 10-K for the fiscal year ended December 31, 2025 and Part 1, Item 1A of our Quarterly Report on Form 10-Q for the fiscal quarter ended March 31, 2026. There have been no material changes in our risk factors since our Quarterly Report on Form 10-Q for the fiscal quarter ended March 31, 2026.

Ite m 5. Other Information

During the 2026 second quarter, no director or Section 16 officer adopted or terminated any Rule 10b5-1 plans or non-Rule 10b5-1 trading arrangements.

Risks Related to Our Limited Operating History, Financial Position and Capital Requirements

We are a preclinical stage biotechnology company with a limited operating history on which to assess our business; we have not completed any clinical trials, and we have no products approved for commercial sale, which may make it difficult to evaluate our current business and likelihood of success and viability.

We are a preclinical stage biotechnology company with a limited operating history. Since our inception, we have incurred operating losses with no corresponding revenue and have utilized substantially all of our resources to identify and develop our product candidates, organize and staff our company, and provide other general and administrative support for our operations. We have no significant experience as a company in initiating, conducting, or completing preclinical studies or clinical trials. In part because of this lack of experience, we cannot be certain that our preclinical studies or clinical trials will begin or be completed on time, if at all. In addition, we have not yet demonstrated an ability to obtain regulatory approvals, manufacture a commercial-scale product, or arrange for a third party to do so on our behalf, or conduct sales, marketing, and distribution activities necessary for successful product commercialization. Consequently, any predictions about our future success or viability may not be as accurate as they could be if we had a longer operating history.

In addition, as our business grows, we may encounter unforeseen expenses, restrictions, difficulties, complications, delays, and other known and unknown factors. We will need to transition at some point from a company with an early research and development focus to a company capable of supporting larger scale clinical trials and eventually commercial activities. We have not yet taken such steps and may not be successful in such a transition.

We will require substantial additional capital to finance our operations in the future. If we are unable to raise such capital when needed, or on acceptable terms, we may be forced to delay, reduce, and/or eliminate one or more of our development programs or future commercialization efforts.

Developing biotechnology products is a long, time-consuming, expensive, and uncertain process that takes years to complete. We expect our expenses to increase in connection with our ongoing activities, particularly as we conduct preclinical studies and anticipated clinical trials of, and seek regulatory approval for, our product candidates, advance discovery efforts with respect to our research and development programs, and advance any future programs and product candidates that we may license. Even if one or more of the programs that we develop is approved for commercial sale, we anticipate incurring significant costs associated with sales, marketing, manufacturing, and distribution activities to launch any such product. Our expenses could increase beyond expectations if we are required by the FDA or other regulatory agencies to perform preclinical studies or clinical trials in addition to or more expansive than those that we currently anticipate. Because the design and outcome of our planned and anticipated clinical trials are highly uncertain, we cannot reasonably estimate the actual amount of funding that will be necessary to successfully complete the development and commercialization of any program we develop. Our future capital requirements depend on many factors, including but not limited to:

• the scope, design, progress, results, and costs of discovery and preclinical and clinical development for our product candidates;

• the costs and timing of completing clinical and commercial-scale manufacturing activities;

• the costs and timing of preparing, filing, and prosecuting patent applications, maintaining, defending, and enforcing our intellectual property and proprietary rights, and defending intellectual property-related claims, including claims of infringement, misappropriation, or other violations of third-party intellectual property;

• the costs, timing, and outcome of the regulatory review of our product candidates and obtaining the requisite regulatory approvals;

• the costs of our future commercialization activities, either on our own or in collaboration with others, including product sales, marketing, manufacturing, and distribution for any product candidate for which we receive regulatory approval;

• the revenue, if any, received from commercial sales of product candidates for which we receive regulatory approval;

• the success of our current or future collaborations, including our collaboration with Paragon and Paragon Laboratories pursuant to the Paragon ADOA and Paragon Research Letter Agreement, respectively, and the success of the Paragon License Agreement and any future license agreements we enter into with Paragon;

• our ability to establish and maintain additional collaborations on favorable terms, if at all;

• the extent to which we acquire or in-license products, intellectual property, and technologies;

• the costs of operational, financial and management information systems and associated personnel; and

• the costs of operating as a public company.

As a result, we will require substantial additional funding to continue our operations. As of September 30, 2026, we had $456.2 million in cash and cash equivalents. We expect that our existing cash and cash equivalents will be sufficient to fund our operating expenses and capital expenditure requirements into 2029. However, we will still need to raise additional capital to continue to fund our operations in the future. If we are unable to raise additional capital when needed, that could raise substantial doubt about our ability to continue as a going concern.

We may be required to seek additional funds sooner than planned through public or private equity offerings, debt financings, collaborations and licensing arrangements, or other sources, and adequate additional financing may not be available to us on acceptable terms, or at all. Such financing may dilute our shareholders or the failure to obtain such financing may restrict our operating activities. Any additional fundraising efforts may divert our management from their day-to-day activities, which may adversely affect our business. To the extent that we raise additional capital through the sale of equity or convertible debt securities, the ownership interest of our shareholders will be diluted, and the terms may include liquidation or other preferences and anti-dilution protections that adversely affect the rights of our shareholders. Debt financing may result in the imposition of debt covenants, increased fixed payment obligations or other restrictions that may affect our business. If we raise additional funds through upfront payments or milestone payments pursuant to future collaborations with third parties, we may have to relinquish valuable rights to our product candidates, or grant licenses on terms that are not favorable to us. Our ability to raise additional capital may be adversely impacted by global macroeconomic conditions and volatility in the credit and financial markets in the United States and worldwide. Our failure to raise capital as and when needed or on acceptable terms would have a negative impact on our financial condition and our ability to pursue our business strategy, and we may have to delay, reduce the scope of, suspend, or eliminate one or more of our product candidates, clinical trials, or future commercialization efforts or cease our operations.

In addition, as a result of our assumption of the Paragon ADOA in connection with the Merger, we are subject to the obligation to grant to Parasa on December 31, 2026, warrants to purchase a number of shares equal to 1.00% of our outstanding shares of common stock as of the date of the grant on a fully-diluted basis, with an exercise price equal to the fair market value of the underlying shares on the grant date. Such warrants granted will result in further dilution to all of our securityholders.

We expect to continue to incur losses for the foreseeable future and may not be able to achieve or sustain profitability in the future. We have no products approved for sale, have not generated any revenue from our product candidates, and may never generate revenue or become profitable.

Investment in biotechnology product development is a highly speculative undertaking and entails substantial upfront capital expenditures and significant risks that any product candidate will fail to demonstrate adequate efficacy or an acceptable safety profile, gain regulatory approval, and become commercially viable. We have no products approved for commercial sale, have not generated any revenue from product sales to date, and continue to incur significant research and development and other expenses related to our ongoing operations. We do not expect to generate product revenue unless or until we successfully complete preclinical and clinical development and obtain regulatory approval for, and then successfully commercialize, at least one of our product candidates.

We may never succeed in these activities and, even if we do, may never generate revenues that are significant or large enough to achieve profitability. If we are unable to raise sufficient additional capital to advance a product candidate to commercialization or generate sufficient revenue through the sale of any approved products, we may be unable to continue operations without additional funding.

We incurred significant net losses in each period since we commenced operations in November 2024. We generated net losses of $35.7 million for the period from November 2024 (inception) to December 31, 2025 and net losses of $46.4 million and $77.3 million during the three and nine months ended September 30, 2026, respectively. As of September 30, 2026, we had an accumulated deficit of $113.0 million. We expect to continue to incur losses for the foreseeable future. Our operating expenses and net losses may fluctuate significantly from quarter to quarter and year to year. We anticipate that our expenses will increase substantially if and as we:

• advance our existing and future product candidates through preclinical and clinical development;

• seek to identify additional product candidates;

• maintain, expand, enforce, defend, and protect our intellectual property portfolio;

• seek, obtain, and maintain regulatory approvals for our product candidates;

• seek to identify, establish, and maintain additional collaborations and license agreements;

• make milestone payments to Paragon under the Paragon License Agreement and Paragon ADOA, and to Paragon Laboratories under the Paragon Research Letter Agreement, and under any additional future collaboration or license agreements that we enter into;

• ultimately establish a sales, marketing, and distribution infrastructure to commercialize any drug products for which we may obtain regulatory approval, either on our own or in collaboration with others;

• generate revenue from commercial sales of product candidates for which we receive regulatory approval, if any;

• hire additional personnel, including research and development, clinical, and commercial personnel;

• add operational, financial, and management information systems and personnel, including personnel to support our product development;

• acquire or in-license products, intellectual property, and technologies;

• establish clinical and commercial-scale current good manufacturing practices ("cGMP") capabilities through a third-party or our own manufacturing facility; and

• operate as a public company.

In addition, our expenses will increase if, among other things, we are required by the FDA or other regulatory authorities to perform clinical trials or studies in addition to, or different than, those that we currently anticipate, there are any delays in initiating or completing our clinical trials or the development of any of our product candidates, or there are any third-party challenges to our intellectual property or we need to defend against any intellectual property-related claim.

Even if we obtain regulatory approval for, and are successful in commercializing, one or more of our product candidates, we expect to incur substantial additional research and development and other expenditures to develop and market additional product candidates and/or to expand the approved indications of any marketed product. We may encounter unforeseen expenses, difficulties, complications, delays, and other unknown factors that may adversely affect our business. The size of our future net losses will depend, in part, on the rate of future growth of our expenses and our ability to generate revenue.

Our failure to become profitable would decrease our value and could impair our ability to raise capital, maintain our research and development efforts, expand our business, and/or continue our operations. A decline in the value of our stock could also cause shareholders to lose all or part of their investment.

Risks Related to Our Discovery, Development, and Commercialization

We face competition from entities that have developed or may develop product candidates for the diseases addressed by our product candidates.

The development and commercialization of drugs is highly competitive. Our product candidates, if approved, will face significant competition and our failure to effectively compete may prevent us from achieving significant market penetration. We compete with a variety of multinational biopharmaceutical companies, specialized biotechnology companies, and emerging biotechnology companies, as well as academic institutions, governmental agencies, and public and private research institutions, among others. If approved for the treatment of patients with Alzheimer's disease, KRSA-028 would compete with two anti-amyloid antibody therapies that have been approved by the FDA for treatment of early Alzheimer's disease: lecanemab (Leqembi), marketed by Eisai and Biogen, and donanemab (Kisunla), marketed by Eli Lilly. We are aware of several companies with product candidates in clinical development for the treatment of patients with Alzheimer's disease, including Roche (including Genentech, its wholly owned subsidiary), Lilly, Eisai, Biogen, AbbVie, Merck, Sanofi, Bristol Myers Squibb, Voyager Therapeutics, Denali Therapeutics, Acumen, Alzheon, AC Immune, Alnylam Pharmaceuticals, ChainGen, Akeso, and others. Several of these companies are developing anti-Aβ antibodies that, like KRSA-028, are designed to use transferrin receptor-mediated transport to increase brain exposure, including Roche's trontinemab, which is being evaluated in Phase 3 clinical trials, and AbbVie's ABBV-1758 and Denali Therapeutics' DNL921, each of which is in early-stage clinical development. In addition, Lilly is evaluating remternetug, an antibody that, like KRSA-028, targets a pyroglutamate-modified form of Aβ, in Phase 3 clinical trials, including with subcutaneous administration. Many of the companies with which we are currently competing or will compete against in the future have significantly greater financial resources and expertise in research and development, manufacturing, preclinical testing, conducting clinical trials, obtaining regulatory approvals, and commercialization than we do, and are further along in the clinical development and/or commercialization process. Mergers and acquisitions in the pharmaceutical and biotechnology industry may result in even more resources being concentrated among a smaller number of our competitors. Smaller or early-stage companies may also prove to be significant competitors, particularly through collaborative arrangements with large and established companies. These competitors also compete with us in recruiting and retaining qualified scientific and management personnel, establishing clinical trial sites, raising capital, enrolling patients in clinical trials, establishing and defending rights to intellectual property, as well as in acquiring technologies complementary to, or necessary for, our product candidates.

Our competitors have developed or are developing, and may in the future develop, product candidates or products competitive with our product candidates. Competitive therapeutic treatments include those that have already been approved and accepted by the medical community and any potential new treatments, including those currently under clinical development. Our success will depend partially on our ability to develop and commercialize products that have a competitive safety, efficacy, dosing, and/or presentation profile. Our commercial opportunity and success will be reduced or eliminated if competing products are (or are perceived to be) safer, more effective, less expensive, or have a more attractive dosing profile or presentation than the products we develop, or if competitors develop products or biosimilars that enter the market more quickly than us and gain market acceptance. Conversely, the lack of commercial success of other competing therapies may raise concerns about the financial viability of our product candidates.

In addition, because of the competitive landscape for Alzheimer's disease, we may also face competition for establishing clinical trial sites and enrolling patients. Patient enrollment will depend on many factors, including if potential clinical trial patients choose to undergo treatment with approved products or enroll in competitors' ongoing clinical trials for product candidates that are under development for the same indications as our product candidates. An increase in the number of approved products for the indications we are targeting with our product candidates will likely further exacerbate this competition. Our inability to enroll a sufficient number of patients could, among other impacts, delay our development timeline, which may further harm our competitive position.

Our programs are in the preclinical stages of development and may fail in development or suffer delays that materially and adversely affect our viability. If we or our future collaborators are unable to complete development of or commercialize our product candidates, or experience significant delays in doing so, our business will be materially harmed.

We have no commercially approved products. Our programs are in the preclinical stages of development, and we have not initiated or completed any clinical trials. As a result, we expect it will be many years before we commercialize any product candidate, if ever. Our ability to achieve and sustain profitability depends on obtaining regulatory approvals for, and successfully commercializing, our product candidates, either alone or with third parties, and we cannot guarantee that we will ever obtain regulatory approval for any of our product candidates. We have not yet demonstrated our ability to complete any clinical trials, obtain regulatory approvals, manufacture a commercial-scale product or arrange for a third party to do so on our behalf, or conduct sales and marketing activities necessary for successful product commercialization. Before obtaining regulatory approval for the commercial distribution of any product candidate, we or an existing or future collaborator must conduct extensive preclinical tests and clinical trials to demonstrate the safety and efficacy in humans of the product candidate.

We or our collaborators may experience delays in initiating or completing preclinical studies or clinical trials. We or our collaborators also may experience numerous unforeseen events during, or as a result of, any future preclinical studies or clinical trials that we could conduct that could delay or prevent our ability to receive regulatory approval or commercialize our product candidates, including:

• regulators, such as the FDA, institutional review boards ("IRBs"), or comparable foreign regulatory authorities may not authorize us or our investigators to commence a clinical trial or conduct a clinical trial at a prospective trial site;

• we may experience delays in reaching, or fail to reach, agreement on acceptable terms with prospective trial sites and prospective clinical research organizations ("CROs"), the terms of which can be subject to extensive negotiation and may vary significantly among different CROs and trial sites;

• clinical trial sites may deviate from the trial protocol, fail to conduct trials in a compliant manner, or drop out of a trial, which may require that we add new clinical trial sites or investigators or otherwise negatively impact the timing or integrity of our clinical trial(s);

• clinical trials of any product candidates may fail to show safety or efficacy, or may produce negative or inconclusive results and we may decide, or regulators may require us, to conduct additional preclinical studies or clinical trials or we may decide to abandon a product development program;

• the number of subjects required for clinical trials of any product candidates may be larger than we can anticipate, and enrollment in these clinical trials may be slower than we anticipate or subjects may drop out of these clinical trials or fail to return for post-treatment follow-up at a higher rate than we anticipate;

• our third-party contractors may fail to comply with regulatory requirements or meet their contractual obligations to us in a timely manner, or at all, or may deviate from the clinical trial protocol or suffer other quality or performance issues that negatively impact the timing or integrity of our clinical trial(s);

• we may elect to, or regulators, IRBs or ethics committees may require that we or our investigators, suspend or terminate clinical research or trials for various reasons, including noncompliance with regulatory requirements or a finding that the participants in our clinical trials are being exposed to unacceptable health risks;

• the cost of clinical trials of any of our product candidates may be greater than we anticipate;

• the quality of our product candidates or other materials necessary to conduct clinical trials of our product candidates may be inadequate to initiate or successfully complete a given clinical trial;

• we may be unable to manufacture sufficient quantities of our product candidates for use in clinical trials;

• reports from clinical testing of other therapies may raise safety or efficacy concerns about our product candidates;

• we may fail to establish an appropriate safety profile for a product candidate based on preclinical or clinical data for such product candidate as well as data emerging from other therapies in the same class as such product candidate; and

• the FDA or other regulatory authorities may require us to submit additional data, such as long-term toxicology studies, or impose other requirements before permitting us to initiate a clinical trial.

Commencing clinical trials in the United States is subject to acceptance by the FDA of an IND and finalizing the trial design based on discussions with the FDA. Commencing clinical trials in jurisdictions outside of the United States is similarly subject to acceptance by the applicable regulatory authority of clinical trial documentation following discussions with such authority. In the event that the FDA or other applicable regulatory authority requires us to complete additional preclinical studies or we are required to satisfy other FDA or foreign regulatory authority requests, respectively, prior to commencing clinical trials, the start of our first clinical trial for a product candidate may be delayed. Even after we receive and incorporate guidance from these regulatory authorities, the FDA or other regulatory authorities could disagree as to whether we have satisfied their requirements to commence any clinical trial or change their position on the acceptability of our trial design or the clinical endpoints selected, which may require us to complete additional preclinical studies or clinical trials, delay the enrollment of our clinical trials or impose stricter approval conditions than we currently expect. There are analogous processes and risks applicable to clinical trial applications in other countries, including but not limited to Canada, New Zealand, Australia, countries in the European Union ("EU"), and countries in Asia.

We may not have the financial resources to continue development of our product candidates if we experience any issues that delay or prevent regulatory approval of, or our ability to commercialize, our product candidates. We or our future collaborators' inability to complete development of, or commercialize our product candidates, or significant delays in doing so, could have a material and adverse effect on our business, financial condition, results of operations, and prospects.

We are substantially dependent on the success of KRSA-028, and our anticipated clinical trials for such product candidate may not be successful.

Our future success is substantially dependent on our ability to timely obtain regulatory approval for, and then successfully commercialize, KRSA-028. We are initially investing a majority of our efforts and financial resources into the research and development of this program. After we complete clinical trial-enabling activities, we plan to submit a CTN in Australia or a CTA in New Zealand by the end of 2026 and an IND in the United States in the first quarter of 2027. Pharmacokinetic data in healthy volunteers is anticipated by mid-year 2027 and interim proof-of-concept data in Alzheimer's disease patients is anticipated by year-end 2027 or the first quarter of 2028. The success of KRSA-028 depends on demonstrating one or more clinical advantages over other approved anti-Aβ antibody products or product candidates in clinical development, which may include favorable data on amyloid plaque clearance, slowing of cognitive decline or disease progression, reduced rates of amyloid-related imaging abnormalities ("ARIA"), improved hematologic safety, and/or a convenient low-volume subcutaneous route of administration, particularly as lecanemab has been approved for subcutaneous administration throughout the course of treatment and other anti-Aβ antibodies, including remternetug, are being developed for subcutaneous administration. Our belief that KRSA-028 will show favorable clinical data is based in part on the assumption that the increased brain penetration observed in mice and non-human primates ("NHPs") through the use of the proprietary THETA platform, which confers binding to the transferrin receptor ("TfR1"), will translate to humans. If our Phase 1 clinical trial of KRSA-028 or additional clinical trials do not demonstrate adequate brain delivery or improvements versus the limitations of other TfR1-based approaches, the clinical and commercial potential of KRSA-028 will be significantly and adversely affected.

Our product candidates will require completion of preclinical, clinical, and manufacturing activities, regulatory approval in multiple jurisdictions, substantial investment, and significant marketing efforts before we generate any revenues from product sales. We are not permitted to market or promote our product candidates before we receive regulatory approval from the FDA and comparable foreign regulatory authorities, and we may never receive such regulatory approvals.

The success of our product candidates will depend on a variety of factors. We do not have complete control over many of these factors, including certain aspects of clinical development and the regulatory submission process, potential threats to our intellectual property rights, potential threats from the intellectual property rights of third parties and the manufacturing, marketing, distribution, and sales efforts of any future collaborator. Accordingly, we cannot assure you that we will ever be able to generate revenue through the sale of these product candidates, even if approved. If we are not successful in obtaining regulatory approval for and commercializing KRSA-028 or future product candidates, or are significantly delayed in doing so, our business will be materially harmed.

Our product candidates are based on novel technology in fields that have seen limited success in drug development, which makes it difficult to predict the time and cost of product candidate development and subsequently obtaining regulatory approval.

We have focused our research and development efforts on addressing neurodegenerative diseases. Collectively, efforts by biopharmaceutical companies in the field of neurodegenerative diseases have seen limited success in drug development. There are few effective therapeutic options available for patients with neurodegenerative diseases, such as Alzheimer's disease and Parkinson's disease. Our future success is highly dependent on the successful development of our THETA™ platform and our product candidates for treating neurodegenerative diseases. Developing and, if approved, commercializing our product candidates for treatment of neurodegenerative diseases subjects us to a number of challenges, including engineering product candidates to cross the blood brain barrier ("BBB") to enable optimal concentration of the therapeutic in the brain and obtaining regulatory approval from the FDA and other regulatory authorities who have only a limited set of precedents to rely on.

Our approach to the treatment of neurodegenerative diseases aims to identify and select targets with a link to neurodegenerative diseases; to identify and develop molecules that engage the intended target; to, where possible, identify and develop biomarkers, which are biological molecules found in blood, other bodily fluids, or tissues that are signs of a normal or abnormal process or of a condition or disease, to select patient populations and demonstrate, where possible, target engagement, pathway engagement, and impact on disease progression of our molecules; and to engineer our molecules to cross the BBB and act directly in the brain. This strategy may not prove to be successful. We may not be able to discover, develop, and utilize biomarkers to demonstrate target engagement, pathway engagement, and the impact on disease progression of our product candidates. We cannot be sure that our approach will yield satisfactory therapeutic products that are safe and effective, scalable, or profitable. Moreover, public perception of drug safety issues, including adoption of new therapeutics or novel approaches to treatment, may adversely influence the willingness of subjects to participate in clinical trials, or if approved, of physicians to subscribe to novel treatments.

If we do not achieve our projected development objectives in the time frames we announce and expect, the commercialization of our product candidates may be delayed which may harm our reputation and prospects, increase our expenses, and cause our stock price to decline.

From time to time, we estimate the timing of the anticipated accomplishment of various scientific, clinical, regulatory and other product development goals, which we sometimes refer to as milestones. These milestones may include the commencement or completion of scientific studies and clinical trials, such as the expected timing for the initiation of our Phase 1 clinical trial of KRSA-028, the timing for receipt of clinical data, and the timing for the submission of regulatory filings. From time to time, we may publicly announce the expected timing of some of these milestones. All of these milestones are and will be based on numerous assumptions. The actual timing of these milestones can vary dramatically compared to our estimates, in many cases for reasons beyond our control. If we do not meet these milestones as publicly announced, or at all, our prospects and reputation may be adversely affected, and our stock price may decline. Additionally, delays relative to our projected timelines are likely to cause overall expenses to increase, which may require us to raise additional capital sooner than expected and prior to achieving targeted development milestones.

Our approach to the discovery and development of our product candidates is unproven, and we may not be successful in our efforts to build a pipeline of product candidates with commercial value.

Our approach to the discovery and development of our product candidates leverages established mechanisms of action and incorporates advanced antibody engineering to optimize half-life and other properties designed to overcome limitations of existing therapies, including increased binding affinity, and TfR1 shuttling for delivering large molecule drugs across the BBB, enabling higher drug concentration inside the brain. Our product candidates are purposefully designed to improve upon existing product candidates and products while maintaining the same, established mechanisms of action. However, the scientific research that forms the basis of our efforts to develop differentiated product candidates using half-life extension technologies, effector function modification, and/or the TfR1-based THETA technology to deliver large molecule drugs across the BBB, is ongoing and may not result in viable product candidates. We have no clinical data on product candidates using TfR1-based THETA technology in neurodegenerative diseases and demonstrating whether they are safe or effective for long-term treatment in humans. We also have no clinical data to indicate whether our antibody engineering designed to optimize half-life and modify effector function enhances brain exposure or translates into improved safety, tolerability, convenience, or efficacy in humans. The long-term safety and efficacy of our product candidates compared to currently approved products is unknown.

We may ultimately discover that utilizing half-life extension technologies, effector function modulation, and the TfR1-based THETA technology to target 3pE-Aβ for our specific indications and any product candidates resulting therefrom do not possess certain properties required for therapeutic effectiveness. We currently have only preclinical data regarding the increased half-life properties, effector function modulation, and targeting mechanism of our product candidates, and the same results may not be seen in humans. In addition, product candidates using half-life extension technologies and effector function modulation, or that are designed to bind to 3pE-Aβ and clear amyloid plaques, may demonstrate different chemical, pharmacological and biological properties in patients than they do in laboratory studies. This technology and any product candidates resulting therefrom may not demonstrate the same chemical and pharmacological properties in humans and may interact with human biological systems in unforeseen, ineffective, or harmful ways. Many product candidates that appeared highly promising in preclinical studies or in early-stage clinical trials have failed when advanced into, or further in, clinical development.

In addition, other companies are developing drug products that target Aβ or utilize TfR1-mediated delivery technologies for central nervous system indications, or that utilize half-life extension technology and/or effector function modulation for other targets. The failure of those companies to demonstrate the safety and/or efficacy of their product candidates may be harmful to our business, financial condition, results of operations, and prospects. Conversely, if those companies are successful in demonstrating safety and/or efficacy of their product candidates, these competitive products may instead gain and hold the applicable market.

In addition, we may in the future seek to discover and develop product candidates that are based on novel targets and technologies that are unproven. If our discovery or business development activities fail to identify novel targets or technologies for drug development, or such targets or technologies prove to be unsuitable for treating human disease, we may not be able to develop viable additional product candidates. We and our future collaborators may never receive approval to market and commercialize any product candidate. Even if we or a future collaborator obtains regulatory approval, the approval may be for targets, disease indications or patient populations that are not as broad as we intended or desired or may require labeling that includes significant use or distribution restrictions or safety warnings. If the products resulting from our product candidates prove to be ineffective, unsafe, or commercially unviable, our product candidates and pipeline would have little, if any, value, which would have a material and adverse effect on our business, financial condition, results of operations, and prospects.

and 272 more changes in the filing

Other information 1 change

During the quarter ended September 30, 2026, no director or Section 16 officer adopted or terminated any Rule 10b5-1 trading arrangements or non-Rule 10b5-1 trading arrangements (in each case, as defined in Item 408(a) of Regulation S-K).

Exhibits 41 changes

Inline XBRL Instance Document.

Agreement and Plan of Merger and Reorganization, dated as of April 1, 2026, by and among Cyclerion Therapeutics, Inc., Cariboos Merger Sub Corp., Cariboos Merger Sub II, LLC and Korsana Biosciences, Inc.

Amendment No. 1 to Agreement and Plan of Merger and Reorganization, dated as of April 17, 2026, by and among Cyclerion Therapeutics, Inc., Cariboos Merger Sub Corp., Cariboos Merger Sub II, LLC and Korsana Biosciences, Inc.

Restated Articles of Organization of Cyclerion Therapeutics, Inc.

Articles of Amendment to the Restated Articles of Organization of Cyclerion Therapeutics, Inc., dated May 15, 2023.

Articles of Amendment to the Restated Articles of Organization of Cyclerion Therapeutics, Inc., dated May 19, 2023, designating the Series A Convertible Preferred Stock.

Articles of Amendment to the Restated Articles of Organization of Cyclerion Therapeutics, Inc., effective September 8, 2026 (Reverse Stock Split).

Articles of Amendment to the Restated Articles of Organization of Cyclerion Therapeutics, Inc., effective September 8, 2026 (Name Change).

Articles of Amendment to the Restated Articles of Organization of Cyclerion Therapeutics, Inc. designating the Series B Non-Voting Convertible Preferred Stock, effective September 8, 2026.

Amended and Restated Bylaws of Cyclerion Therapeutics, Inc.

Form of Merger Pre-Funded Warrant.

Contingent Value Rights Agreement, dated as of September 8, 2026, by and between Cyclerion Therapeutics, Inc. and Broadridge Corporate Issuer Solutions, LLC, as rights agent.

Form of Indemnification Agreement for directors and officers of the Company.

Korsana Biosciences, Inc. 2025 Equity Incentive Plan.

First Amendment to Korsana Biosciences, Inc. 2025 Equity Incentive Plan.

Korsana Biosciences, Inc. 2026 Stock Incentive Plan.

Korsana Biosciences, Inc. 2026 Employee Stock Purchase Plan.

Amended and Restated Offer Letter, dated as of September 8, 2026, by and between Korsana Biosciences, Inc. and Jonathan Violin, Ph.D.

Amended and Restated Offer Letter, dated as of September 8, 2026, by and between Korsana Biosciences, Inc. and Mark Vignola, Ph.D.

Amended and Restated Offer Letter, dated as of September 8, 2026, by and between Korsana Biosciences, Inc. and Matthew Leoni, M.D.

Certificate Certification of Chief Executive Officer Principal Executive Officer Pursuant to Rules 13a-14(a) and 15d-14(a) under the Securities Exchange Act of 1934, as Adopted Pursuant to Section 302 of the Sarbanes-Oxley Act of 2002.

Certificate Certification of Chief Financial Officer Principal Financial Officer Pursuant to Rules 13a-14(a) and 15d-14(a) under the Securities Exchange Act of 1934, as Adopted Pursuant to Section 302 of the Sarbanes-Oxley Act of 2002.

Certificate Certification of Chief Executive Officer Principal Executive Officer Pursuant to 18 U.S.C. Section 1350, as Adopted Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002.

Certificate Certification of Chief Financial Officer Principal Financial Officer Pursuant to 18 U.S.C. Section 1350, as Adopted Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002.

Inline XBRL Instance Document – the instance document does not appear in the Interactive Data File because XBRL tags are embedded within the Inline XBRL document.

Inline XBRL Taxonomy Extension Schema Document. With Embedded Linkbase Documents

Cover Page Interactive Data File (embedded within the Inline XBRL document)

** Furnished herewith.

# Indicates management contract or compensatory plan.

† Portions of this exhibit (indicated by "***") have been omitted in accordance with the rules of the Securities and Exchange Commission.

†† This certification will not be deemed "filed" for purposes of Section 18 of the Exchange Act or otherwise subject to the liability of that section. Such certification will not be deemed to be incorporated by reference into any filing under the Securities Act or the Exchange Act, except to the extent specifically incorporated by reference into such filing.

1 unchanged paragraph

CYCLERION THERAPEUTICS, INC.

President and Chief Executive Officer (Principal Executive Officer)

Chief Financial Officer (Principal Financial and Accounting Officer)

Date: August 4, 2026

Korsana Biosciences, Inc.

Date:November 5, 2026

Jonathan Violin, Ph.D.

Chief Executive Officer and President

Date:November 5, 2026

Chief Financial Officer