Aspen Neuroscience: Securities offering (amended)

Cover page 4 changes

As filed with the Securities and Exchange Commission on October 22, 26, 2026

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Subject to Completion, Dated October 22, 26, 2026

This is the initial public offering of shares of common stock by Aspen Neuroscience, Inc. We are offering 9,375,000 shares of our common stock. The initial public offering price is expected to be between $ $15.00 and $ $17.00 per share .

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We have granted the underwriters an option for a period of 30 days to purchase up to 1,406,250 additional shares of common stock from us at the initial public offering price, less the underwriting discounts and commissions.

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Prospectus summary 17 changes

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We have granted the underwriters an option for a period of 30 days to purchase up to 1,406,250 additional shares of common stock from us at the initial public offering price, less the underwriting discounts and commissions.

Common stock to be outstanding immediately after this offering shares (or shares if the underwriters exercise their option to purchase additional shares of our common stock in full).

29,078,600 shares (or 30,484,850 shares if the underwriters exercise their option to purchase additional shares of our common stock in full).

We estimate that the net proceeds to us from this offering will be approximately $ $134.5 million (or approximately $ $155.4 million if the underwriters exercise their option to purchase additional shares of our common stock in full) from the sale of the shares of common stock offered by us in this offering, based on an assumed initial public offering price of $ $16.00 per share, which is the midpoint of the price range set forth on the cover page of this prospectus, and after deducting the estimated underwriting discounts and commissions and estimated offering expenses payable by us.

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The number of shares of our common stock to be outstanding after this offering is based on 194,712,305 19,703,600 shares of our common stock outstanding as of June 30, 2026 after giving effect to (i) the automatic conversion of all outstanding shares of our convertible preferred stock into 177,593,856 17,971,324 shares of our common stock immediately prior to the closing of this offering, and (ii) the treatment as outstanding of 6,153,610 622,707 shares of common stock previously subject to full recourse promissory notes, which became outstanding upon the forgiveness of the related promissory notes in August 2026 (5,550,221 (561,646 shares) and September 2026 (603,389 (61,061 shares) (the Note Forgiveness). See Note 13 to our unaudited interim financial statements included elsewhere in this prospectus for additional information related to the Note Forgiveness. The number of shares outstanding excludes:

30,078,745 3,043,497 shares of common stock issuable upon the exercise of stock options under our 2018 Stock Plan (2018 Plan) outstanding as of June 30, 2026, with a weighted-average exercise price of $0.68 $6.75 per share;

270,000 27,314 shares of common stock issuable upon exercise of stock options granted under our 2018 Plan subsequent to June 30, 2026, with a weighted-average exercise price of $0.99 $9.79 per share;

6,799,243 shares of our common stock reserved for future issuance under the general share reserve of our 2026 Equity Incentive Plan (2026 Plan) (which number includes 3,634,825 new shares remaining available for issuance plus up to a maximum of 3,164,418 shares subject to outstanding awards granted under our the 2018 Plan which will become available for issuance under after the effective date of the 2026 Plan upon its effectiveness), are subsequently forfeited, cancelled, withheld or reacquired), as well as any automatic increases in the number of shares of common stock reserved for future issuance under the 2026 Plan, and any reserved shares not issued or subject to outstanding awards as more fully described under the 2026 Plan after the effective date terms of the 2026 Plan that are subsequently forfeited or terminated, all of which shares shall become available for issuance under described in the 2026 Plan; section titled Executive and Director Compensation Employee Stock Plans ;

872,358 shares of our common stock reserved for future issuance under the Executive Chair Reserve of our 2026 Plan, which is available solely for the issuance of shares pursuant to awards granted to our Executive Chair, Faheem Hasnain, as more fully described under the terms of the 2026 Plan described in the section titled Executive and Director Compensation Employee Stock Plans ;

290,786 shares of our common stock reserved for future issuance under our 2026 Employee Stock Purchase Plan (ESPP), which will become effective as of immediately prior to the completion of this offering, as well as any automatic increases in the number of shares of common stock reserved for future issuance under the ESPP, as more fully described under the terms of the ESPP as described in the section titled Executive and 175,691 Director Compensation Employee Stock Plans ; and 17,778 shares of common stock issuable upon the exercise of a warrant outstanding as of June 30, 2026, at an exercise price of $0.78 $7.71 per share.

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a -for- 1-for-9.8821 reverse stock split of our common stock, effected on , October 23, 2026 (the Stock Split);

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the automatic conversion of all outstanding shares of our convertible preferred stock into 177,593,856 17,971,324 shares of our common stock immediately prior to the closing of this offering;

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See Note 13 to our unaudited interim financial statements included elsewhere in this prospectus for additional information related to the Note Forgiveness.

Weighted-average shares used in net loss per common share calculation, basic and diluted (1) 10,816,448 10,214,636 10,318,638 9,261,740 1,094,550 1,033,651 1,044,175 937,224 Pro forma net loss per common share, basic and diluted (unaudited) (2) $ (0.19 (1.86 ) $ (0.47 (4.64 ) Pro forma weighted-average shares used in pro forma net loss per common share calculation, basic and diluted (unaudited) (2) 194,563,914 136,117,025 19,688,581 13,774,106 (1) See Note 12 to our audited financial statements included elsewhere in this prospectus for an explanation of the methods used to calculate historical net loss per share, basic and diluted, and the weighted-average number of shares of common stock used in the computation of the per share amounts.

(2) Unaudited pro forma net loss per share, basic and diluted, attributable to common stockholders, is calculated giving effect to (i) the conversion of all outstanding shares of our convertible preferred stock into shares of our common stock, as if such conversion had occurred at the beginning of the period, or the issuance dates of such shares, if later, and (ii) the Note Forgiveness and the resulting treatment of 6,153,610 622,707 shares of common stock as outstanding, as if the Note Forgiveness had occurred on January 1, 2025. Unaudited pro forma net loss per share attributable to common stockholders does not include the shares expected to be sold and related proceeds to be received in this offering. Unaudited pro forma net loss for the year ended December 31, 2025 includes estimated non-cash stock-based compensation expense of approximately $1.8 million resulting from the Note Forgiveness, which we expect to recognize in our historical results in the third quarter of 2026, and such expense is not reflected in unaudited pro forma net loss for the six months ended June 30, 2026. Unaudited pro forma net loss per share attributable to common stockholders for the six months ended June 30, 2026 and for the year ended December 31, 2025 was calculated using the weighted-average number of shares of common stock outstanding, including the pro forma effect of (i) the conversion of all outstanding shares of our convertible preferred stock into shares of our common stock, as if such conversion had occurred at the beginning of the period, or the issuance dates of such shares, if later, and (ii) the treatment as outstanding of the 6,153,610 622,707 shares of common stock subject to the Note Forgiveness, as if the Note Forgiveness had occurred on January 1, 2025. See Note 13 to our unaudited interim financial statements included elsewhere in this prospectus for additional information related to the Note Forgiveness.

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(1) Gives effect to (i) the automatic conversion of all outstanding shares of our convertible preferred stock into 177,593,856 17,971,324 shares of our common stock and the related reclassification of the carrying value of the convertible preferred stock to permanent equity immediately prior to the closing of this offering, and (ii) the Note Forgiveness, including the recognition of estimated non-cash stock-based compensation expense of approximately $1.8 million. See Note 13 to our unaudited interim financial statements included elsewhere in this prospectus for additional information related to the Note Forgiveness.

(2) Gives effect to (i) the pro forma adjustments set forth in footnote (1) above, and (ii) the issuance and sale of 9,375,000 shares of our common stock in this offering at the assumed initial public offering price of $ $16.00 per share, which is the midpoint of the price range set forth on the cover page of this prospectus, after deducting the estimated underwriting discounts and commissions and estimated offering expenses payable by us. Each $1.00 increase or decrease in the assumed initial public offering price of $ $16.00 per share would increase or decrease, as applicable, the pro forma as adjusted amount of each of our cash, cash equivalents, and marketable securities, working capital, total assets, and total stockholders (deficit) equity by approximately $ $8.7 million, assuming that the number of shares offered by us, as set forth on the cover page of this prospectus, remains the same and after deducting the estimated underwriting discounts and commissions and estimated offering expenses payable by us. Each increase or decrease of 1.0 million shares in the number of shares offered by us at the assumed initial public offering price of $ $16.00 per share would increase or decrease, as applicable, the pro forma as adjusted amounts of each of our cash, cash equivalents, and marketable securities, working capital, total assets, and total stockholders (deficit) equity by approximately $ $14.9 million, after deducting the estimated underwriting discounts and commissions and estimated offering expenses payable by us.

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Risk factors 7 changes

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Based on our current operating plans, we believe that the net proceeds from this offering, together with our existing cash, cash equivalents and marketable securities, will be sufficient to fund our operations into . the second half of 2028. In particular, we expect that the net proceeds from this offering and our existing cash, cash equivalents and marketable securities will allow us to continue to fund the Phase 1/2a ASPIRO trial evaluating sasineprocel in patients with sporadic and genetic PD, to continue to fund the development of sasineprocel in PD patients, including initiating a Phase 3 trial, and to continue to fund the development of our microglia programs through the initiation of IND-enabling studies, and the remainder for working capital and other general purposes. We have based these estimates on assumptions that may prove to be wrong, and we could use our capital resources sooner than we currently expect. Our operating plans and other demands on our cash resources may change as a result of many factors currently unknown to us, and we may need to seek additional funds sooner than planned. The net proceeds of this offering, together with our existing cash, cash equivalents and marketable securities, will not be sufficient to complete the Phase 1/2a ASPIRO trial, the Phase 3 trial for sasineprocel, which we intend to initiate prior to the completion of the Phase 1/2a ASPIRO trial, or the development of sasineprocel or any other current or future product candidates. After this offering, we will require additional capital in order to advance our current and future product candidates through clinical trials, regulatory approval, and commercialization. Accordingly, we will need to obtain substantial additional funding in connection with our continuing operations. Our ability to raise additional funds may be adversely impacted by global economic conditions, disruptions to, and volatility in, the credit and financial markets in the United States and worldwide, and diminished liquidity and credit availability. If the equity and credit markets deteriorate, it may make any necessary debt or equity financing more difficult, more costly, and more dilutive. If we are unable to raise capital when needed or on attractive terms, we could be forced to delay, reduce, or eliminate our research and development programs or any future commercialization efforts, or even cease operations. We expect to finance our cash needs through public or private equity or debt financings or other capital sources, including potential collaborations, licenses, royalty financing and other similar arrangements. In addition, we may seek additional capital due to favorable market conditions or strategic considerations even if we believe we have sufficient funds for our current or future operating plans. Attempting to secure additional financing may divert our management from our day-to-day activities, which may adversely affect our ability to develop our product candidates.

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The initial public offering price of our common stock is substantially higher than the pro forma as adjusted net tangible book value per share of our outstanding common stock immediately after the closing of this offering. Purchasers of common stock in this offering will experience immediate dilution of approximately $ $8.36 per share, assuming an initial public offering price of $ $16.00 per share, which is the midpoint of the price range set forth on the cover page of this prospectus. In the past, we issued options to acquire common stock at prices significantly below the initial public offering price. To the extent these outstanding options are ultimately exercised, investors purchasing common stock in this offering will sustain further dilution. For a further description of the dilution that you will experience immediately after this offering, see the section titled Dilution.

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Following the completion of this offering, our executive officers, directors, and greater than 5% stockholders, in the aggregate, will own approximately % 44% of our outstanding common stock (assuming no exercise of the underwriters option to purchase additional shares and no exercise of outstanding options and without giving effect to any potential purchases by such persons in this offering). As a result, such persons, acting together, will have the ability to significantly influence all matters submitted to our board of directors or stockholders for approval, including the appointment of our management, the election and removal of directors and approval of any significant transaction, as well as our management and business affairs. This concentration of ownership may have the effect of delaying, deferring, or preventing a change in control, impeding a merger, consolidation, takeover or other business combination involving us, or discouraging a potential acquiror from making a tender offer or otherwise attempting to obtain control of our business, even if such a transaction would benefit other stockholders. Additionally, the concentration of stock ownership may adversely affect the trading price of our common stock due to investors perception that conflicts of interest may exist or arise.

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Based on shares of common stock outstanding as of June 30, 2026, upon the closing of this offering, we will have a total of 29,078,600 shares of common stock outstanding, assuming no exercise of the underwriters option to purchase additional shares and no exercise of outstanding options. Of these shares, only the 9,375,000 shares of common stock sold in this offering by us, plus any shares sold upon exercise of the underwriters option to purchase additional shares, will be freely tradable, without restriction, in the public market immediately following this offering, unless they are purchased by one of our affiliates.

Our directors and executive officers and substantially all of our securityholders have entered into lock-up agreements with the representatives pursuant to which they may not, with limited exceptions and among other things, for a period of 180 days from the date of this prospectus, offer, sell or otherwise transfer or dispose of any of our securities, without the prior written consent of Leerink Partners LLC, Piper Sandler & Co., Stifel, Nicolaus & Company, Incorporated and UBS Securities LLC. The underwriters may permit our officers, directors, and other securityholders who are subject to the lock-up agreements to sell shares prior to the expiration of the lock-up agreements at any time in their sole discretion. See the section titled Underwriting. Sales of these shares, or perceptions that they will be sold, could cause the trading price of our common stock to decline. After the lock-up agreements expire, up to an additional 19,703,600 shares of common stock will be eligible for sale in the public market, of which 12,762,164 shares will be held by directors, executive officers and other affiliates and will be subject to volume limitations under Rule 144 under the Securities Act, in each case based on shares of our common stock outstanding as of June 30, 2026 and without giving effect to any potential purchases by such persons in this offering.

In addition, as of June 30, 2026, 30,078,745 3,043,497 shares of common stock that are subject to outstanding options under our employee benefit plans will become eligible for sale in the public market to the extent permitted by the provisions of various vesting schedules, the lock-up agreements, and Rule 144 and Rule 701 under the Securities Act. If these additional shares of common stock are sold, or if it is perceived that they will be sold, in the public market, the trading price of our common stock could decline.

After this offering, the holders of 18,956,358 shares of our outstanding common stock, or approximately % 65.2% of our total outstanding common stock based on shares outstanding as of June 30, 2026, will be entitled to rights with respect to the registration of their shares under the Securities Act, subject to vesting and the 180-day lock-up agreements described above. See the section titled Description of Capital Stock Registration Rights. Registration of these shares under the Securities Act would result in the shares becoming freely tradable without restriction under the Securities Act, except for shares held by affiliates, as defined in Rule 144 under the Securities Act. Any sales of securities by these stockholders could have a material adverse effect on the trading price of our common stock.

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Use of proceeds 6 changes

We estimate that the net proceeds to us from this offering will be approximately $ $134.5 million (or approximately $ $155.4 million if the underwriters exercise their option to purchase additional shares in full), based on the assumed initial public offering price of $ $16.00 per share, which is the midpoint of the price range set forth on the cover page of this prospectus, and after deducting the estimated underwriting discounts and commissions and estimated offering expenses payable by us.

Each $1.00 increase (decrease) in the assumed initial public offering price of $ $16.00 per share would increase (decrease) the net proceeds to us from this offering by approximately $ $8.7 million, assuming that the number of shares offered by us, as set forth on the cover page of this prospectus, remains the same and after deducting the estimated underwriting discounts and commissions and estimated offering expenses payable by us. Each increase (decrease) of 1.0 million in the number of shares we are offering would increase (decrease) the net proceeds to us from this offering, after deducting the estimated underwriting discounts and commissions and estimated offering expenses payable by us, by $ $14.9 million, assuming the assumed initial public offering price stays the same. We do not expect that a change in the offering price or the number of shares by these amounts would have a material effect on our intended uses of the net proceeds from this offering, although it may affect how soon we may need to seek additional capital.

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approximately $ $8.0 million to continue funding the Phase 1/2a ASPIRO trial evaluating sasineprocel in patients with sporadic and genetic PD;

approximately $ $110.0 million to initiate and fund a Phase 3 trial evaluating sasineprocel in patients with sporadic and genetic PD, with plans to initiate such Phase 3 trial prior to the completion of the Phase 1/2a ASPIRO trial;

approximately $ $4.0 million to continue funding the development of our microglia programs, including initiating IND-enabling studies; and the remainder for working capital and other general corporate purposes.

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Based on our current operating plans, we believe that the estimated net proceeds from this offering, together with our existing cash, cash equivalents and marketable securities, will be sufficient to fund our operations into . the second half of 2028. We have based these estimates on assumptions that may prove to be wrong, and we could use our capital resources sooner than we currently expect. Additionally, our expected use of existing cash, cash equivalents and marketable securities and our net proceeds from this offering represent our intentions based upon our current plans and business conditions, which could change in the future as our plans and business conditions evolve. The amounts and timing of our actual expenditures may vary significantly depending on numerous factors, including the progress and costs of our development activities, the status of and results from clinical trials and preclinical studies, as well as any collaborations that we may enter into with third parties for our products, and the amount of cash used in our operations and any unforeseen cash needs as well as other factors described in the sections titled Risk Factors, Management s Discussion and Analysis of Financial Condition and Results of Operations, and Special Note Regarding Forward-Looking Statements.

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Capitalization 11 changes

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on a pro forma basis to reflect (i) the automatic conversion of all outstanding shares of our convertible preferred stock into 177,593,856 17,971,324 shares of our common stock and the related reclassification of the carrying value of the convertible preferred stock to permanent equity immediately prior to the closing of this offering, (ii) the Note Forgiveness, including the treatment of 6,153,610 622,707 shares of common stock as outstanding, and (iii) the filing and effectiveness of our amended and restated certificate of incorporation immediately prior to the closing of this offering; and on a pro forma as adjusted basis to give further effect to our issuance and sale of 9,375,000 shares of our common stock in this offering at an assumed initial public offering price of $ $16.00 per share, which is the midpoint of the price range set forth on the cover page of this prospectus, after deducting the estimated underwriting discounts and commissions and estimated offering expenses payable by us.

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(2) Reflects the number of shares that will be authorized under our amended and restated certificate of incorporation, which will become effective immediately prior to the closing of this offering, and assumes the completion of the Stock Split prior to the effectiveness of the registration statement of which this prospectus forms a part. Except as otherwise indicated, the other information in the table above, including the number of shares issued and outstanding, does not give effect to the Stock Split.

If the underwriters option to purchase additional shares is exercised in full, our pro forma as adjusted cash, cash equivalents and marketable securities, additional paid-in capital, total stockholders equity, and total capitalization as of June 30, 2026, would be $ million, $ million, $ million, and $ million, respectively.

shares of common stock reserved for future issuance under our 2026 Plan (which number includes shares remaining available for issuance under our 2018 Plan, which will become available for issuance under the 2026 Plan upon its effectiveness), as well as any automatic increases in the number of shares of common stock reserved for future issuance under the 2026 Plan and any reserved shares not issued or subject to outstanding awards under the 2026 Plan after the effective date of the 2026 Plan that are subsequently forfeited or terminated, all of which shares shall become available for issuance under the 2026 Plan;

Preferred stock, $0.0001 par value; no shares authorized, issued or outstanding, actual (other than the convertible preferred stock set forth above), 10,000,000 shares authorized, no shares issued or outstanding, pro forma and pro forma as adjusted (2) Common stock, $0.0001 par value; 228,898,561 shares authorized; 17,118,449 1,732,276 shares issued; and 10,964,839 1,109,569 shares outstanding, actual; 500,000,000 shares authorized, 194,712,305 19,703,600 shares issued and outstanding, pro forma; 500,000,000 shares authorized, 29,078,600 shares issued and shares outstanding, pro forma as adjusted (2) Additional paid-in capital 13,854 354,467 13,855 354,484 488,983 Accumulated other comprehensive loss (42 ) (42 ) (42 ) Accumulated deficit (264,886 ) (266,709 ) (266,709 ) Total stockholders (deficit) equity (251,073 ) 87,735 222,235 Total capitalization $ 87,735 $ 87,735 $ 222,235 (1) Each $1.00 increase or decrease in the assumed initial public offering price of $ $16.00 per share, which is the midpoint of the price range set forth on the cover page of this prospectus, would increase or decrease, as applicable, the pro forma as adjusted amount of each of our cash, cash equivalents and marketable securities, additional paid-in capital, total stockholders (deficit) equity, and total capitalization by approximately $ $8.7 million, assuming that the number of shares offered by us, as set forth on the cover page of this prospectus, remains the same and after deducting the estimated underwriting discounts and commissions and estimated offering expenses payable by us. Each increase or decrease of 1.0 million shares in the number of shares offered by us at the assumed initial public offering price of $ $16.00 per share would increase or decrease, as applicable, the pro forma as adjusted amount of each of our cash, cash equivalents and marketable securities, additional paid-in capital, total stockholders (deficit) equity, and total capitalization by approximately $ $14.9 million, after deducting the estimated underwriting discounts and commissions and estimated offering expenses payable by us.

The number of shares of our common stock issued and outstanding, pro forma and pro forma as adjusted in the table above, is based on 194,712,305 19,703,600 shares of our common stock outstanding as of June 30, 2026 after giving effect to (i) the automatic conversion of all outstanding shares of our convertible preferred stock into 177,593,856 17,971,324 shares of our common stock immediately prior to the closing of this offering and (ii) the Note Forgiveness, including the treatment of 6,153,610 622,707 shares of common stock as outstanding. See Note 13 to our unaudited interim financial statements included elsewhere in this prospectus for additional information related to the Note Forgiveness. The number of shares of our common stock issued and outstanding, pro forma and pro forma as adjusted in the table above excludes:

30,078,745 3,043,497 shares of common stock issuable upon the exercise of stock options outstanding as of June 30, 2026 under our 2018 Plan, with a weighted-average exercise price of $0.68 $6.75 per share;

270,000 27,314 shares of common stock issuable upon exercise of stock options granted subsequent to June 30, 2026, with a weighted-average exercise price of $0.99 $9.79 per share;

6,799,243 shares of our common stock reserved for future issuance under the general share reserve of our 2026 Equity Incentive Plan (which number includes 3,634,825 new shares plus up to a maximum of 3,164,418 shares subject to outstanding awards granted under the 2018 Plan which after the effective date of the 2026 Plan are subsequently forfeited, cancelled, withheld or reacquired), as well as any automatic increases in the number of shares of common stock reserved for future issuance under the 2026 Plan, as more fully described under the terms of the 2026 Plan described in the section titled Executive and Director Compensation Employee Stock Plans ;

872,358 shares of our common stock reserved for future issuance under the Executive Chair Reserve of our 2026 Plan, which is available solely for the issuance of shares pursuant to awards granted to our Executive Chair, Faheem Hasnain, as more fully described under the terms of the 2026 Plan described in the section titled Executive and Director Compensation Employee Stock Plans ;

290,786 shares of our common stock reserved for future issuance under our ESPP, 2026 Employee Stock Purchase Plan, which will become effective as of immediately prior to the completion of this offering, as well as any automatic increases in the number of shares of common stock reserved for future issuance under the ESPP, as more fully described under the terms of the ESPP as described in the section titled Executive and 175,691 Director Compensation Employee Stock Plans ; and 17,778 shares of common stock issuable upon the exercise of a warrant outstanding as of June 30, 2026, at an exercise price of $0.78 $7.71 per share.

Dilution 14 changes

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As of June 30, 2026, our historical net tangible book value (deficit) was $(251.1) million, or $(14.67) $(226.28) per share of our common stock, based on 17,118,449 1,732,276 shares of common stock issued and 10,964,839 1,109,569 shares of common stock outstanding as of such date. Our historical net tangible book value (deficit) per share represents total tangible assets less total liabilities and convertible preferred stock, which is not included within permanent equity, divided by the number of shares of common stock issued and outstanding at June 30, 2026.

On a pro forma basis, after giving effect to (i) the automatic conversion of all outstanding shares of our convertible preferred stock into 177,593,856 17,971,324 shares of our common stock and the related reclassification of the carrying value of the convertible preferred stock to permanent equity immediately prior to the closing of this offering, and (ii) the Note Forgiveness, including the resulting treatment of 6,153,610 622,707 shares of common stock as outstanding, our pro forma net tangible book value as of June 30, 2026 would have been $87.7 million, or $0.45 $4.45 per share of our common stock.

After giving further effect to the sale and issuance of 9,375,000 shares of our common stock in this offering at an assumed initial public offering price of $ $16.00 per share, which is the midpoint of the price range set forth on the cover page of this prospectus, and after deducting the estimated underwriting discounts and commissions and estimated offering expenses payable by us, our pro forma as adjusted net tangible book value as of June 30, 2026 would have been approximately $ $222.2 million, or approximately $ $7.64 per share. This amount represents an immediate increase in pro forma net tangible book value of approximately $ $3.19 per share to our existing stockholders and an immediate dilution in pro forma net tangible book value of approximately $ $8.36 per share to new investors purchasing shares of common stock in this offering.

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Historical net tangible book value (deficit) per share as of June 30, 2026 (14.67 (226.28 ) Pro forma increase in historical net tangible book value per share as of June 30, 2026 attributable to the pro forma adjustments described above 15.12 230.73 Pro forma net tangible book value per share as of June 30, 2026 0.45 4.45 Increase in pro forma net tangible book value per share attributable to new investors participating in this offering 3.19 Pro forma as adjusted net tangible book value per share after this offering 7.64 Dilution per share to new investors participating in this offering $ 8.36 Each $1.00 increase or decrease in the assumed initial public offering price of $ $16.00 per share would increase or decrease, as applicable, the pro forma as adjusted net tangible book value per share after this offering by approximately $ $0.30 per share, and dilution in pro forma as adjusted net tangible book value per share to new investors by approximately $ $0.70 per share, assuming that the number of shares offered by us, as set forth on the cover page of this prospectus, remains the same and after deducting the estimated underwriting discounts and commissions and the estimated offering expenses payable by us. Each increase or decrease of 1.0 million shares in the number of shares of common stock offered by us would increase or decrease, as applicable, our pro forma as adjusted net tangible book value per share after this offering by approximately $ $0.24 per share and decrease or increase, the dilution to investors participating in this offering by approximately $0.24 per share, assuming that the assumed initial public offering price of $16.00 per share remains the same, and after deducting the estimated underwriting discounts and commissions and the estimated offering expenses payable by us. Each decrease of 1.0 million shares in the number of shares of common stock offered by us would decrease our pro forma as applicable, adjusted net tangible book value per share after this offering by approximately $0.26 per share and increase the dilution to investors participating in this offering by approximately $ $0.26 per share, assuming that the assumed initial public offering price of $ $16.00 per share remains the same, and after deducting the estimated underwriting discounts and commissions and the estimated offering expenses payable by us.

If the underwriters exercise their option to purchase additional shares of our common stock in full in this offering, the pro forma as adjusted net tangible book value after the offering would be approximately $ $7.98 per share, the increase in pro forma as adjusted net tangible book value per share to existing stockholders would be approximately $ $3.53 per share, and the dilution per share to investors in this offering would be $ $8.02 per share, in each case assuming an initial public offering price of $ $16.00 per share.

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The following table summarizes on the pro forma as adjusted basis described above, as of June 30, 2026, the differences between the number of shares purchased from us, the total consideration paid to us in cash, and the weighted-average price per share paid by existing stockholders for shares issued prior to this offering and the price to be paid by new investors in this offering. The calculations below are based on an assumed initial public offering price of $ $16.00 per share, before deducting the estimated underwriting discounts and commissions and estimated offering expenses payable by us.

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shares of common stock reserved for future issuance under our 2026 Plan (which number includes shares remaining available for issuance under our 2018 Plan, which will become available for issuance under the 2026 Plan upon its effectiveness), as well as any automatic increases in the number of shares of common stock reserved for future issuance under the 2026 Plan and any reserved shares not issued or subject to outstanding awards under the 2026 Plan after the effective date of the 2026 Plan that are subsequently forfeited or terminated, all of which shares shall become available for issuance under the 2026 Plan;

the percentage of shares of common stock held by existing stockholders will decrease to approximately % 65% of the total number of shares of our common stock outstanding after this offering; and the number of shares held by new investors participating in this offering will increase to , 10,781,250, or approximately % 35% of the total number of shares of our common stock outstanding after this offering.

The foregoing tables and calculations above (other than the historical net tangible book value calculations) are based on 194,712,305 19,703,600 shares of our common stock outstanding as of June 30, 2026 after giving effect to (i) the automatic conversion of all outstanding shares of our convertible preferred stock into 177,593,856 17,971,324 shares of our common stock immediately prior to the closing of this offering, and (ii) the Note Forgiveness, including the treatment of 6,153,610 622,707 shares of common stock as outstanding. See Note 13 to our unaudited interim financial statements included elsewhere in this prospectus for additional information related to the Note Forgiveness. The number of shares of our common stock issued and outstanding as of June 30, 2026 in the foregoing tables and calculations above excludes:

30,078,745 3,043,497 shares of common stock issuable upon the exercise of stock options outstanding as of June 30, 2026 under our 2018 Plan, with a weighted-average exercise price of $0.68 $6.75 per share;

270,000 27,314 shares of common stock issuable upon exercise of stock options granted subsequent to June 30, 2026, with a weighted-average exercise price of $0.99 $9.79 per share;

6,799,243 shares of our common stock reserved for future issuance under the general share reserve of our 2026 Equity Incentive Plan (which number includes 3,634,825 new shares plus up to a maximum of 3,164,418 shares subject to outstanding awards granted under the 2018 Plan which after the effective date of the 2026 Plan are subsequently forfeited, cancelled, withheld or reacquired), as well as any automatic increases in the number of shares of common stock reserved for future issuance under the 2026 Plan, as more fully described under the terms of the 2026 Plan described in the section titled Executive and Director Compensation Employee Stock Plans ;

872,358 shares of our common stock reserved for future issuance under the Executive Chair Reserve of our 2026 Plan, which is available solely for the issuance of shares pursuant to awards granted to our Executive Chair, Faheem Hasnain, as more fully described under the terms of the 2026 Plan described in the section titled Executive and Director Compensation Employee Stock Plans ;

290,786 shares of our common stock reserved for future issuance under our ESPP, 2026 Employee Stock Purchase Plan, which will become effective as of immediately prior to the completion of this offering, as well as any automatic increases in the number of shares of common stock reserved for future issuance under the ESPP, as more fully described under the terms of the ESPP as described in the section titled Executive and 175,691 Director Compensation Employee Stock Plans ; and 17,778 shares of common stock issuable upon the exercise of a warrant outstanding as of June 30, 2026, at an exercise price of $0.78 $7.71 per share.

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MD&A 2 changes

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In various closings from October 2025 to November 2025, we issued and sold to investors in private placements an aggregate of 76,173,492 shares of Series C convertible preferred stock at a per share purchase price of $1.5179, and we received gross proceeds of approximately $115.6 million. As of June 30, 2026, we had cash, cash equivalents and marketable securities of $72.4 million. Together with the estimated net proceeds from this offering, we believe our cash, cash equivalents and marketable securities will be sufficient to fund our operating expenses and capital expenditures through . into the second half of 2028. We have based this estimate on assumptions that may prove to be wrong, and we could use our capital resources sooner than we expect. Additionally, our expected use of existing cash, cash equivalents, marketable securities, and our net proceeds from this offering represent our intentions based upon our current plans and business conditions, which could change in the future as our plans and business conditions evolve. See Liquidity and Capital Resources Funding Requirements below.

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As of June 30, 2026, we had cash, cash equivalents and marketable securities of $72.4 million. Based on our current operating plan, we estimate that our existing cash, cash equivalents and marketable securities as of June 30, 2026 will not be sufficient to fund our capital and operating expenditures for at least the twelve months following the date the unaudited financial statements were issued, and there is substantial doubt about our ability to continue as a going concern. Nevertheless, together with the estimated net proceeds from this offering, we believe our cash, cash equivalents and marketable securities will be sufficient to fund our operating expenses and capital expenditures through . into the second half of 2028. However, our forecast of the period of time through which our financial resources will be adequate to support our operations is a forward-looking statement that involves risk and uncertainties, and actual results could vary materially. We have based this estimate on assumptions that may prove to be wrong, and we could expend our capital resources sooner than we currently expect. Additionally, our expected use of existing cash, cash equivalents, marketable securities, and our net proceeds from this offering represent our intentions based upon our current plans and business conditions, which could change in the future as our plans and business conditions evolve.

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Business 1 change

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Personalized approach: Sasineprocel is an autologous product candidate designed to minimize the risk of immune rejection and eliminate the need for long-term immunosuppression and its associated risks. In addition, based on market research, we believe patients prefer the personalized approach of autologous cell therapy as compared to gene or allogenic allogeneic therapies.

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Executive and Director Compensation 22 changes

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Pursuant to the terms of his employment offer letter, Mr. Meeter was granted an initial stock option for 1,000,000 101,193 shares in March 2025 in connection with his commencement of employment with us and an additional stock option for 340,000 34,405 shares in November 2025 in connection with our Series C preferred stock financing, which was a qualifying financing under the terms of his offer letter. In connection with our Series C preferred stock financing, our named executive officers also received refresh stock option grants in November 2025 for the following number of shares: Dr. McDevitt 3,825,000 387,063 shares; Mr. Meeter 875,000 88,543 shares, and Mr. Raineri 800,000 80,954 shares.

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(3) The market value of the unvested shares is calculated based on an estimated fair market value of $0.88 $8.70 per share as of December 31, 2025.

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(6) The shares were purchased by Dr. McDevitt at $0.35 $3.46 per share in April 2021 and are subject to our right of repurchase upon Dr. McDevitt s termination of service, which repurchase right lapses upon his continued services through the earlier of the date of enrollment of the first patient in a Phase 2 or Phase 3 trial-ready cohort for a product candidate or a Change in Control (as defined in the 2026 Plan).

(7) The shares were purchased by Dr. McDevitt at $0.35 $3.46 per share in April 2021 and are subject to our right of repurchase upon Dr. McDevitt s termination of service, which repurchase right lapses upon his continued services through the earlier of the date of receipt of a bona fide written third party offer to acquire the Company or substantially all its assets, subject to the Company s entering into exclusivity with such third party on such or more favorable terms, or a Change in Control (as defined in the 2026 Plan).

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In August 2026, we entered into a loan forgiveness and option amendment agreement with Dr. McDevitt. Pursuant to this agreement, we forgave the outstanding principal and accrued interest, in the aggregate amount of approximately $2,114,989.07, owed by Dr. McDevitt under promissory notes that Dr. McDevitt entered into in order to pay the purchase price for shares of our common stock received upon the exercise of stock options. In exchange for such loan forgiveness, Dr. McDevitt agreed to extend the monthly vesting schedule of the remaining unvested shares subject to the option to purchase 3,825,000 387,063 shares that had been granted to Dr. McDevitt in November 2025, such that this option will vest in full six years following its vesting commencement date of November 20, 2025, rather than pursuant to its original four year vesting schedule. In addition, Dr. McDevitt further agreed that any refresh or top-up option or other equity award that may be granted to him in connection with this offering will be subject to a six-year monthly or quarterly vesting schedule. In addition, pursuant to this agreement, Dr. McDevitt s option was further amended to provide for vesting acceleration in the event of Dr. McDevitt s qualifying termination of employment, the terms of which are described below under Potential Payments Upon Termination or Change in Control.

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Pursuant to Mr. Meeter s participation agreement, upon a regular termination, Mr. Meeter also will be entitled to receive (i) a pro rata portion of his target bonus for the calendar year of termination, payable in a lump sum following the effective date of his release, and (ii) accelerated vesting of the stock options granted to him on March 13, 2025 for 1,000,000 101,193 shares and November 26, 2025 for 340,000 34,405 shares, as if he had continued in employment for an additional nine months following the termination date.

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Our board of directors adopted the Cash Incentive Plan in , October 2026 which is applicable commencing with our 2026 bonus program. Our Cash Incentive Plan provides for the grant of cash-based incentive awards to our employees, including our named executive officers. The following summary describes the material terms of our Cash Incentive Plan. This summary is not a complete description of all provisions of our Cash Incentive Plan and is qualified in its entirety by reference to our Cash Incentive Plan, which is filed as an exhibit to the registration statement of which this prospectus is a part.

Administration . Our Cash Incentive Plan will be administered by an officer committee consisting of our Chief Executive Officer and our Chief Financial Officer for employees who are not executive officers and by our compensation committee for our executive officers. As used in this summary, the term Administrator refers to our compensation committee or the officer committee, as applicable. The Administrator has the discretionary authority to, among other things, determine award recipients, grant awards, establish all terms and conditions of awards, interpret the Cash Incentive Plan and awards, approve target and actual awards, adopt sub-plans, prescribe rules for administration, interpretation and application or of the Cash Incentive Plan, and otherwise do all things necessary or desirable to carry out the purposes of our Cash Incentive Plan.

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Our board of directors adopted the 2026 Plan in October 2026, and our stockholders approved the 2026 Plan in October 2026. The 2026 Plan will become effective upon the execution of the underwriting agreement for this offering. The 2026 Plan is the successor to our 2018 Stock Plan, or the 2018 Plan, which is described below. No further grants will be made under the 2018 Plan following the effectiveness of the 2026 Plan.

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Authorized Shares . The maximum number of shares of common stock that may be issued under our 2026 Plan will initially be 6,799,243 shares, which number is the sum of: 3,634,825 new shares, plus the applicable number of returning shares from our 2018 Plan not exceeding a maximum of 3,164,418 such returning shares. For such purposes, returning shares from our 2018 Plan means the applicable number shares subject to equity awards granted under the 2018 Plan that are outstanding on the date of this offering, and that are not issued because such share award or any portion thereof expires or otherwise terminates without all of the shares covered by such share award having been issued, are not issued because such award or any portion thereof is settled in cash, are forfeited back to or repurchased by us because of the failure to meet a contingency or condition required for the vesting of such shares, are used to pay the exercise price of an award, or are used to satisfy tax withholding obligations with respect to an award.

The number of shares of common stock reserved for issuance under our 2026 Plan will automatically increase on January 1 of each year, beginning on January 1, 2027, and continuing through and including January 1, 2036, by 5% of the sum of the total number of shares of common stock outstanding plus the number of shares issuable upon the exercise of any unexercised pre-funded warrants, in each case which are outstanding on December 31 of the immediately preceding calendar year, or a lesser number of shares determined by our board of directors. The maximum number of shares that may be issued upon the exercise of ISOs under our 2026 Plan is 6,799,243 shares.

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Executive Chair Reserve . In addition to the general share reserve, the 2026 Plan establishes a separate reserve of 872,358 shares of common stock, referred to as the Executive Chair Reserve, which is available solely for the issuance of shares pursuant to awards granted to our Executive Chair, Faheem Hasnain, in satisfaction of the Company s obligations under the Executive Chair Agreement (as defined below). The Executive Chair Reserve is separate from, and in addition to, the general share reserve (including any annual increases thereto). Shares from the Executive Chair Reserve may not be granted to any other participant under the 2026 Plan. To the extent shares from the Executive Chair Reserve are not granted, or are subject to an award that expires, is forfeited, cancelled, settled in cash, or otherwise terminates without issuance, or become no longer issuable because the applicable conditions are not satisfied, such shares will be permanently cancelled and will not become available for issuance under the 2026 Plan to any other participant. For the avoidance of doubt, the Company s obligation to grant awards from the Executive Chair Reserve may, in the Company s discretion, be satisfied in cash in lieu of shares to the extent provided in the Executive Chair Agreement, and any shares not issued as a result will be permanently cancelled. No shares from the Executive Chair Reserve may be transferred to or combined with the general share reserve. The 2026 Plan requires stockholder approval for any amendment to the 2026 Plan that would modify the exclusive use restrictions applicable to the Executive Chair Reserve or make shares from the Executive Chair Reserve available for awards to any person other than the Executive Chair.

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The Company maintains the 2018 Plan. The maximum aggregate number of shares of common stock that may be issued under the 2018 Plan is 42,146,191. 4,264,902. The purpose of the 2018 Plan is to provide awards in the form of stock options and restricted stock awards in order to provide an incentive to attract, retain and reward persons performing services for the Company and to motivate such persons to contribute to the growth and profitability of the Company. Employees, directors and consultants are eligible to receive awards under the 2018 Plan.

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Our board of directors adopted the ESPP in October 2026, and our stockholders approved the ESPP in October 2026. The ESPP will become effective upon the execution of the underwriting agreement for this offering. The purpose of the ESPP is to secure the services of new employees, to retain the services of existing employees and to provide incentives for such individuals to exert maximum efforts toward our success and that of our affiliates. The ESPP includes two components. One component is designed to allow our eligible U.S. employees to purchase common stock in a manner that may qualify for favorable tax treatment under Section 423 of the Code. In addition, purchase rights may be granted under a component that does not qualify for such favorable tax treatment when necessary or appropriate to permit participation by our eligible employees who are foreign nationals or employed outside of the United States while complying with applicable foreign laws.

Authorized Shares. The maximum aggregate number of shares of common stock that may be issued under our ESPP is 290,786 shares. The number of shares of common stock reserved for issuance under our ESPP will automatically increase on January 1 of each calendar year, beginning on January 1, 2027 and continuing through and including January 1, 2036, by the lesser of 1% of the sum of the total number of shares of our common stock outstanding plus the number of shares of stock issuable upon the exercise of any unexercised pre-funded warrants, in each case which are outstanding on December 31 of the preceding calendar year, (2) 436,179 shares and (3) a number of shares determined by our board. Shares subject to purchase rights granted under our ESPP that terminate without having been exercised in full will not reduce the number of shares available for issuance under our ESPP.

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Each new non-employee director who joins our board of directors following the closing of this offering will receive a stock option grant under the 2026 Plan for 23,500 shares and which will vest in 36 equal monthly installments following the date of grant subject to the non-employee director s continuous service through applicable vesting dates.

On the date of each annual meeting of our stockholders following the closing of this offering, each continuing non-employee director will receive a stock option grant under the 2026 Plan for 11,750 shares which will vest in full upon the earlier of the one year anniversary of the grant date or the date of the next annual meeting, subject to the non-employee director s continuous service.

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In September 2026, we entered into loan forgiveness and option amendment agreements with each of Messrs. Hasnain and Spaventa. Pursuant to these agreements, we forgave the outstanding principal and accrued interest, in the amount of approximately $212,928 for Mr. Hasnain and $30,550 for Mr. Spaventa, under promissory notes that were entered into to pay the purchase price for shares of our common stock received upon the exercise of stock options by each of Messrs. Hasnain and Spaventa. In exchange for the Company forgiving such amounts, Mr. Hasnain agreed to extend the monthly vesting schedule of the remaining unvested shares subject to an option to purchase 410,000 41,489 shares granted to him in November 2025, and Mr. Spaventa agreed to extend the monthly vesting schedule of the then remaining unvested shares subject to an option to purchase 190,000 19,226 shares granted to him in November 2025, in each case such that these options will vest in full after six years following the vesting commencement date of November 20, 2025, rather than the original four years following such date. In addition, Mr. Hasnain agreed that any refresh or top-up option or other equity award that may be granted to him in connection with this offering will be subject to a six year monthly or quarterly vesting schedule.

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(2) In November 2025, we granted Dr. Daniel an option to purchase 360,000 36,429 shares of common stock and in December 2025, we granted Dr. Daniel an option to purchase 100,000 10,119 shares of common stock, each with an exercise price of $0.58 $5.74 per share. The shares subject to each of the options will vest in 48 equal monthly installments over a four-year period measured from the vesting commencement date of November 20, 2025, subject to continued services. As of December 31, 2025, Dr. Daniel held an aggregate of 1,124,789 113,820 outstanding and unexercised stock options and did not hold any other stock awards.

(3) In November 2025, we granted Mr. Hasnain an option to purchase 410,000 41,489 shares of common stock with an exercise price of $0.58 $5.74 per share. The shares subject to the option will vest in 48 equal monthly installments over a four-year period measured from the vesting commencement date of November 20, 2025, subject to continued services. As of December 31, 2025, Mr. Hasnain held an aggregate of 680,000 68,811 outstanding and unexercised stock options and did not hold any other stock awards. As described above, in September 2026, Mr. Hasnain agreed to extend the monthly vesting schedule of the remaining unvested shares subject to his option, such that this option will vest in full six years following its vesting commencement date of November 20, 2025, rather than pursuant to its original four year vesting schedule.

(4) In November 2025, we granted Ms. Peterson an option to purchase 190,000 19,226 shares of common stock with an exercise price of $0.58 $5.74 per share. The shares subject to the option will vest in 48 equal monthly installments over a four-year period measured from the vesting commencement date of November 20, 2025, subject to continued services. As of December 31, 2025, Ms. Peterson held an aggregate of 556,931 56,357 outstanding and unexercised stock options and did not hold any other stock awards.

(5) In November 2025, we granted Mr. Spaventa an option to purchase 190,000 19,226 shares of common stock with an exercise price of $0.58 $5.74 per share. The shares subject to the option will vest in 48 equal monthly installments over a four-year period measured from the vesting commencement date November 20, 2025. As of December 31, 2025, Mr. Spaventa held an aggregate of 480,000 48,572 outstanding and unexercised stock options and did not hold any other stock awards. As described above, in September 2026, Mr. Spaventa agreed to extend the monthly vesting schedule of the remaining unvested shares subject to his option, such that this option will vest in full six years following its vesting commencement date of November 20, 2025, rather than pursuant to its original four year vesting schedule.

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Certain Relationships and Related Person Transactions 6 changes

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The following table summarizes the Series C convertible preferred stock purchased by holders of more than 5% of our capital stock as of the date of the applicable closing of the Series C convertible preferred stock, and entities affiliated with certain of our executive officers and directors. Each outstanding share of convertible preferred stock, including the shares identified in the table below, will convert into shares of common stock at a ratio of one-for-one and the conversion ratios will be proportionally adjusted immediately prior to the closing of this offering.

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We entered into a voting agreement in October 2018, as last amended and restated in October 2025 (Voting Agreement), with the holders of our convertible preferred stock and certain holders of our common stock, including the holders of more than 5% of our capital stock listed above as well as entities with which certain of our directors are affiliated, pursuant to which the following directors were each elected to serve as members on our board of directors and, as of the date of this prospectus, continue to so serve: Caryn Peterson, Peter A. Thompson, M.D., Thomas Daniel, M.D., Douglas Fisher, M.D., Andrew Spaventa, Damien McDevitt, Ph.D., and Faheem Hasnain. Pursuant to the Voting Agreement, Dr. McDevitt, as our Chief Executive Officer, serves on our board of directors as the CEO director. Mr. Spaventa was initially selected to serve on our board of directors as representative of the holders of our common stock, Ms. Peterson was initially selected to serve on our board of directors as representative of the holders of our Series Seed convertible preferred stock, Dr. Thompson and Mr. Dr. Daniel were initially selected to serve on our board of directors as representatives of the holders of our Series A convertible preferred stock, and Dr. Fisher was initially selected to serve on our board of directors as a representative of the holders of our Series B convertible preferred stock. Mr. Hasnain was initially selected to serve on our board of directors as the independent director and Chairman of the board of directors.

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In August 2024, Kameel Farag, our former Chief Financial Officer, sold 497,000 50,293 shares of common stock to a preferred shareholder of the Company which were previously early exercised through a promissory note and paid the outstanding promissory note balance of $0.2 million to the Company.

In December 2024, we entered into an agreement to repurchase 1,945,000 196,821 shares of common stock for $1.6 million issued to Dr. McDevitt, which was used to cancel principal and interest of $1.6 million on an outstanding promissory note for the early exercise of shares by Dr. McDevitt. Concurrently, we granted Dr. McDevitt 1,945,000 196,820 new awards with the same vesting terms.

In August 2026, we entered into an agreement to forgive the outstanding principal and accrued interest of approximately $2.1 million on three promissory notes issued to Dr. McDevitt for the early exercise of stock options, representing 5,550,221 561,646 shares of underlying common stock. In connection with the forgiveness, Dr. McDevitt agreed to amend the vesting schedule applicable to his November 2025 option grant for 3,825,000 387,063 shares of common stock, extending the vesting period from four to six years for the remaining unvested options.

In September 2026, we entered into agreements to forgive the outstanding principal and accrued interest of approximately $212,928 and $30,550 on promissory notes issued to Faheem Hasnain and Andrew Spaventa, respectively, for the early exercise of stock options, representing 526,839 53,314 and 76,550 7,747 shares of underlying common stock, respectively. In connection with the forgiveness, Mr. Hasnain and Mr. Spaventa each agreed to amend the vesting schedule applicable to their November 2025 option grants for 410,000 41,489 and 190,000 19,226 shares of common stock, respectively, extending the vesting period from four to six years for the remaining unvested options.

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Principal stockholders 17 changes

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The number of shares beneficially owned by each stockholder is determined under rules issued by the SEC. Under these rules, beneficial ownership includes any shares as to which a person has sole or shared voting power or investment power. Applicable percentage ownership is based on 194,951,589 19,727,905 shares of common stock outstanding on September 15, 2026 which gives effect to the automatic conversion of all outstanding shares of our convertible preferred stock into 177,593,856 17,971,324 shares of our common stock immediately prior to the closing of this offering. We have based our calculation of the percentage of beneficial ownership after this offering on 29,102,905 shares of our common stock outstanding immediately after the closing of this offering, which reflects the conversion of our convertible preferred stock into common stock as described in the prior sentence and further reflects the issuance of shares of common stock in this offering, assuming that the underwriters will not exercise their option to purchase up to an additional 1,406,250 shares of our common stock.

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(1) Consists of 25,586,039 2,589,132 shares of our common stock held by OrbiMed Private Investments VII, LP (OPI VII). OrbiMed Capital GP VII LLC (OrbiMed GP), is the general partner of OPI VII. OrbiMed Advisors LLC (OrbiMed Advisors) is the managing member of OrbiMed GP. By virtue of such relationships, OrbiMed GP VII and OrbiMed Advisors may be deemed to have voting and investment power with respect to the shares held by OPI VII. OrbiMed Advisors exercises investment and voting power through a management committee comprised of Carl L. Gordon, Sven H. Borho, and W. Carter Neild. Each of OrbiMed GP, OrbiMed Advisors, Dr. Gordon, Mr. Borho, and Mr. Neild disclaim beneficial ownership of the shares held by OPI VII, except to the extent of its or his pecuniary interest therein if any. The address for each of the entities and individuals identified in this footnote is c/o OrbiMed Advisors LLC, 601 Lexington Avenue 54th Floor, New York, NY 10022.

(2) Consists of 16,470,124 1,666,663 shares of our common stock held by Gilead Sciences, Inc. (Gilead). The address for Gilead is 333 Lakeside Drive, Foster City, California 94404.

(3) Consists of 13,251,770 1,340,988 shares of our common stock held by Frazier Life Sciences X, L.P. (FLS X). FHMLS X, L.P. is the general partner of FLS X, and FHMLS X, L.L.C. is the general partner of FHMLS X, L.P. James Topper, M.D., Ph.D., and Patrick Heron are the sole managing members of FHMLS X, L.L.C. and share voting and investment power of the securities held by FLS X. Dr. Topper and Mr. Heron disclaim beneficial ownership of such securities except to the extent of their pecuniary interest therein. The address for above referenced entities and persons is 1001 Page Mill Rd., Building 4, Ste. B, Palo Alto, CA 94304.

(4) Q Healthcare Holding LLC (Q Healthcare) is a limited liability company formed pursuant to the regulations of the Qatar Financial Centre and is a wholly-owned subsidiary of Qatar Investment Authority ( QIA ). QIA is the sole member of Q Healthcare. Q Healthcare directly holds 13,176,099 1,333,330 shares of our common stock. Each of QIA and Q Healthcare may be deemed to beneficially own the shares of our common stock held by Q Healthcare. The business address of Q Healthcare and QIA is Ooredoo Tower (Building 14), Al Dafna Street (Street 801), Al Dafna (Zone 61), Doha, Qatar.

(5) Consists of (i) 13,115,315 1,327,182 shares of our common stock held by ARCH Venture Fund X, L.P. (ARCH X) and (ii) 10,815,021 1,094,407 shares of our common stock held by ARCH Venture Fund X Overage, L.P. (ARCH X Overage). ARCH Venture Partners X, L.P. (AVP X LP), is the sole general partner of ARCH X. ARCH Venture Partners X Overage, L.P. (AVP X Overage LP), is the sole general partner of ARCH X Overage. ARCH Venture Partners X, LLC (AVP X LLC), is the sole general partner of each of AVP X LP and AVP X Overage LP. Keith Crandell, Kristina Burow, Steven Gillis, and Robert Nelsen, collectively the AVP X Committee Members, comprise the investment committee of AVP X LLC. AVP X LP and AVP X Overage LP may be deemed to beneficially own the shares held by ARCH X and ARCH X Overage, respectively, AVP X LLC may be deemed to beneficially own the shares held by ARCH X and ARCH X Overage, and each of the AVP X Committee Members may be deemed to share the power to direct the disposition and vote of the shares held by ARCH X and ARCH X Overage. Each of AVP X LP, AVP X Overage LP, AVP X LLC, and the AVP X Committee Members disclaims beneficial ownership except to any pecuniary interest therein. The address for these entities and individuals is in c/o Arch Venture Partners, 8755 W. Higgins Road, Suite 1025, Chicago, IL 60631.

(6) Consists of 12,816,358 1,296,927 shares of our common stock held by Abu Dhabi Investment Authority (ADIA), directly or through one or more of its direct or indirect subsidiaries, including primarily Platinum Falcon B 2018 RSC Limited (Platinum Falcon), a restricted scope company incorporated in the Abu Dhabi Global Market. ADIA is a public institution established by the Government of the Emirate of Abu Dhabi. By reason of its ownership of Platinum Falcon and pursuant to the rules and regulations of the SEC, ADIA may also be deemed to share investment and voting power over and, therefore, beneficial ownership of, the shares held directly by Platinum Falcon. The address for ADIA is 211 Corniche Street, P.O. Box 3600, Abu Dhabi, United Arab Emirates and the address for Platinum Falcon B 2018 RSC Limited is Level 26, Al Khatem Tower, Abu Dhabi Global Market Square, Al Maryah Island, Abu Dhabi, United Arab Emirates.

(7) Consists of (i) 5,091,158 515,192 shares of our common stock held by Medical Excellence Capital Partners, LP and (ii) 5,566,902 563,332 shares of our common stock held by Medical Excellence Capital Partners II, LP.The address for each of the entities identified in this footnote is 355 Old Mill Road, Nissequogue, NY 11780.

(8) Consists of (i) 4,800,221 485,751 shares of our common stock held by Damien McDevitt and Pamela Marnell-McDevitt, Co-trustees of the Marnell-McDevitt Family Trust dated May 2, 2019, of which 925,036 93,607 shares remain subject to performance-based vesting conditions and forfeiture if such conditions are not satisfied, (ii) 250,000 25,299 shares of our common stock held by Finn McDevitt, Trustee of the Finn McDevitt 2025 Irrevocable Trust, (iii) 250,000 25,299 shares of our common stock held by Aran McDevitt, Trustee of the Aran McDevitt 2025 Irrevocable Trust, (iv) 250,000 25,299 shares of our common stock held by Conor McDevitt, Trustee of the Conor McDevitt 2025 Irrevocable Trust and (v) 2,703,870 273,611 shares subject to options that are exercisable within 60 days of September 15, 2026.

(9) Represents 709,270 71,771 shares subject to options that are exercisable within 60 days of September 15, 2026.

(10) Represents 1,114,583 112,786 shares subject to options that are exercisable within 60 days of September 15, 2026.

(11) Consists of (i) 263,421 26,658 shares of our common stock held by Faheem Hasnain, (ii) 359,185 36,349 shares of our common stock held by Hasnain Revocable Trust, (iii) 131,709 13,329 shares of our common stock held by Premier Trust, Inc., Trustee of the Myles J. Hasnain 2021 Irrevocable Trust, (iv) 131,709 13,329 shares of our common stock held by Premier Trust, Inc., Trustee of the Aaron D. Hasnain 2021 Irrevocable Trust and (v) 363,958 36,830 shares subject to options that are exercisable within 60 days of September 15, 2026.

(12) Consists of (i) 173,636 17,572 shares of our common stock held by 2024 Corinne Marie Daniel Irrevocable Trust Dated 12/19/2024, (ii) 173,636 17,572 shares of our common stock held by 2024 Lyle Robert Daniel Irrevocable Trust Dated 12/19/2024, and (iii) 770,206 77,938 shares subject to options that are exercisable within 60 days of September 15, 2026.

(13) Represents 410,473 41,536 shares subject to options that are exercisable within 60 days of September 15, 2026.

(14) Consists of (i) 76,550 7,747 shares of our common stock held by Andrew Spaventa, (ii) 493,251 49,914 shares of our common stock held by The Andrew K. Spaventa Living Trust Dated April 9, 2014, (iii) 200,000 20,239 shares of our common stock held by Sharon Spaventa, (iv) 200,000 20,239 shares of our common stock held by Jon Spaventa, (v) 693,655 70,194 shares of common stock held directly by Axon Holdings, LLC Series XIII - Aspen Seed, of which Mr. Spaventa is a managing partner, (vi) 1,780,946 180,221 shares of our common stock held directly by Axon Holdings, LLC Series XXI - Aspen C, of which Mr. Spaventa is a managing partner, and (vii) 333,542 33,751 shares subject to options that are exercisable within 60 days of September 15, 2026.

(15) Consists of 25,586,039 2,589,132 shares of our common stock held by OPI VII. OrbiMed GP is the general partner of OPI VII, and OrbiMed Advisors is the managing member of OrbiMed GP. By virtue of such relationships, GP VII and OrbiMed Advisors may be deemed to have voting power and investment power over the securities held by OPI VII and as a result, may be deemed to have beneficial ownership over such securities. OrbiMed Advisors exercises voting and investment power through a management committee comprised of Carl L. Gordon, Sven H. Borho, and W. Carter Neild, each of whom disclaims beneficial ownership of the shares held by OPI VII. Peter A. Thompson, M.D., a member of our board of directors, is a member of OrbiMed Advisors. Dr. Thompson disclaims beneficial ownership of the shares held by OPI VII, except to the extent of his pecuniary interest therein, if any.

(16) Consists of (i) 35,813,958 3,624,143 shares of our common stock beneficially owned by our current executive officers and directors and (ii) 7,038,193 712,206 shares subject to options that are exercisable within 60 days of September 15, 2026.

Description of the securities 9 changes

2 unchanged paragraphs

As of June 30, 2026, there were 194,712,305 19,703,600 shares of our common stock outstanding and held of record by 127 stockholders, after giving effect to (i) the automatic conversion of all outstanding shares of our convertible preferred stock into 177,593,856 17,971,324 shares of common stock, which will automatically occur immediately prior to the closing of this offering, and (ii) the Note Forgiveness, including the treatment of 6,153,610 622,707 shares of common stock as outstanding. Based on the number of shares of common stock outstanding as of June 30, 2026, and further assuming the issuance by us of 9,375,000 shares of common stock in this offering, there will be 29,078,600 shares of common stock outstanding upon the closing of this offering.

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Under the terms of our Charter, our board of directors has the authority, without further action by our stockholders, to issue up to 10,000,000 shares of preferred stock. The shares of preferred stock may be issued in series, and shall have such voting powers, full or limited, or no voting powers, and such designations, preferences and relative participating, optional or other special rights, and qualifications, limitations or restrictions thereof, as shall be stated and expressed in the resolution or resolutions providing for the issuance of such stock adopted from time to time by our board of directors. Our board of directors is expressly vested with the authority to determine and fix in the resolution or resolutions providing for the issuances of all or any of the remaining preferred stock the voting powers, designations, preferences and rights, and the qualifications, limitations, or restrictions thereof, of each such series to the full extent now or hereafter permitted by the laws of the State of Delaware.

As of June 30, 2026, options to purchase 30,078,745 3,043,497 shares of our common stock were outstanding, of which 13,287,819 1,344,458 were vested as of that date. For additional information regarding the terms of our 2018 Plan, see the section titled Executive and Director Compensation Employee Stock Plans 2018 Stock Plan.

As of June 30, 2026, the warrants to purchase 175,691 17,778 shares of our common stock are outstanding. On December 20, 2022 in connection with a Loan and Security Agreement (the Loan Agreement) with a lender (the Lender) , we issued Lender a warrant to purchase 131,761 13,333 shares of our common stock at an exercise price of $0.78 $7.71 per share. In conjunction with amending our line of credit with Lender on November 15, 2024, we issued Lender a warrant to purchase 43,930 4,445 shares of our common stock at an exercise price of $0.78. $7.71. The warrants contain a net exercise provision under which the Lender may, in lieu of payment of the exercise price in cash, surrender the warrant, and receive, a net amount of shares of our common stock based on the fair market value of our common stock at the time of the net exercise of the warrant after deduction of the aggregate exercise price. The warrants expire ten years from their date of issuance.

1 unchanged paragraph

Upon the closing of this offering, holders of 187,328,011 18,956,358 shares of our common stock, which includes all of the shares of common stock issuable upon the automatic conversion of convertible preferred stock immediately prior to the closing of this offering and 9,734,155 985,034 shares of common stock held by certain key holders, will be entitled to the following rights with respect to the registration of such shares for public resale under the Securities Act, pursuant to an investors rights agreement by and among us and certain investors. The registration of shares of common stock as a result of the following rights being exercised would enable holders to trade these shares without restriction under the Securities Act when the applicable registration statement is declared effective.

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The ability of our board of directors, without action by the stockholders, to issue up to 10,000,000 shares of undesignated preferred stock with voting or other rights or preferences as designated by our board of directors could impede the success of any attempt to change control of us. These and other provisions may have the effect of deferring hostile takeovers or delaying changes in control or management of our company.

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Business Combination Provision

Our Charter further provides that the approval of the holders of shares representing at least % of the voting power of the voting shares is required in order to approve certain business combinations if an interested stockholder or its affiliates or associates is a party to the transaction and such stockholder and its affiliates own or control 5% or more of the outstanding shares of common stock and our Board had not approved of the transaction prior to such stockholder and its affiliates obtaining such control.

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The amendment of any of the above provisions, except for the provision making it possible for our board of directors to issue preferred stock, would require approval by holders of at least % sixty-six and two-thirds percent (66-2/3%) of the total voting power of all of our outstanding voting stock.

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Shares Eligible For Future Sale 4 changes

1 unchanged paragraph

Based on the number of shares of our common stock outstanding as of June 30, 2026, and assuming (i) the issuance of 9,375,000 shares in this offering, (ii) the automatic conversion of all of our outstanding shares of convertible preferred stock into 177,593,856 17,971,324 shares of common stock and the related reclassification of the carrying value of the convertible preferred stock to permanent equity upon the closing of this offering, (iii) no exercise of the underwriters option to purchase additional shares of common stock and (iv) no exercise of outstanding options, we will have outstanding an aggregate of 29,078,600 shares of common stock following the closing of this offering.

1 unchanged paragraph

The remaining 19,703,600 shares of common stock will be restricted securities, as that term is defined in Rule 144 under the Securities Act. These restricted securities are eligible for public sale only if they are registered under the Securities Act or if they qualify for an exemption from registration under Rule 144 or Rule 701 under the Securities Act, each of which is summarized below. We expect that substantially all of these shares will be subject to the 180-day lock-up period under the lock-up agreements described below.

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1% of the number of shares of our common stock then outstanding, which will equal approximately 290,786 shares immediately after this offering, assuming no exercise of the underwriters option to purchase additional shares; or the average weekly trading volume in our common stock on Nasdaq during the four calendar weeks preceding the filing of a notice on Form 144 with respect to such sale.

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Upon the closing of this offering, holders of 187,328,011 18,956,358 shares of our common stock, which includes all of the shares of common stock issuable upon the automatic conversion of our convertible preferred stock into shares of our common stock immediately prior to the closing of this offering and 9,734,155 985,034 shares of common stock held by certain key holders, will be entitled to various rights with respect to the registration of these shares under the Securities Act upon the closing of this offering. Registration of these shares under the Securities Act would result in these shares becoming freely tradable without restriction under the Securities Act immediately upon the effectiveness of the registration, except for shares purchased by our affiliates. See the section titled Description of Capital Stock Registration Rights for additional information. Shares covered by a registration statement will be eligible for sale in the public market upon the expiration or release from the terms of the lock-up agreements described above.

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Plan of distribution 2 changes

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We estimate expenses payable by us in connection with this offering, other than the underwriting discounts and commissions referred to above, will be approximately $ . $5.0 million. We also have agreed to reimburse the underwriters for up to $ $45,000 for their FINRA counsel fee.

1 unchanged paragraph

We have granted an option to the underwriters, exercisable for 30 days after the date of this prospectus, to purchase up to 1,406,250 additional shares at the initial public offering price, less underwriting discounts and commissions. If the underwriters exercise this option, each underwriter will be obligated, subject to the conditions contained in the underwriting agreement, to purchase a number of additional shares proportionate to that underwriter s initial amount reflected in the above table.

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Notes to the financial statements 5 changes

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except for the third paragraph of Note 13, as to which the date is

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Common stock, $0.0001 par value; 228,898,561 and 137,843,464 shares authorized at December 31, 2025 and 2024, respectively; 16,767,841 1,696,796 and 16,431,101 1,662,716 shares issued at December 31, 2025 and 2024, respectively; 10,614,231 1,074,089 and 10,023,079 1,014,267 shares outstanding at December 31, 2025 and 2024, respectively Additional paid-in capital 11,249 8,517 11,250 8,518 Accumulated other comprehensive income Accumulated deficit (228,340 ) (166,284 ) Total stockholders deficit (217,077 ) (157,727 ) Total liabilities, convertible preferred stock and stockholders deficit $ 143,663 $ 90,211 The accompanying notes are an integral part of these financial statements.

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Weighted-average shares used to calculate net loss per common share, basic and diluted 10,318,638 9,261,740 1,044,175 937,224 The accompanying notes are an integral part of these financial statements.

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St atements of Convertible Preferred Stock and Stockholders Deficit (in thousands, except share data) Convertible Preferred Stock Common Stock Additional Paid-in Accumulated Other Comprehensive Accumulated Total Stockholders Shares Amount Shares Amount Capital Income (Loss) Deficit Deficit Balance at December 31, 2023 101,428,978 $ 223,480 8,898,020 900,420 $ $ 5,252 5,253 $ $ (117,727 ) $ (112,037 ) Vesting of restricted stock 37,500 3,795 Exercise of stock options 1,087,559 110,052 Stock-based compensation 2,707 2,707 Unrealized loss on marketable securities (398 ) (398 ) Net loss (48,557 ) (48,557 ) Balance at December 31, 2024 101,428,978 $ 223,480 10,023,079 1,014,267 $ $ 8,517 8,518 $ $ (166,284 ) $ (157,727 ) Issuance of Series C preferred stock, net of issuance costs of $271 76,173,492 115,353 Conversion of preferred to common stock (8,614 ) (25 ) Exercise of stock options 335,879 33,989 Vesting of restricted stock 254,412 25,745 Stock-based compensation 2,517 2,517 Unrealized loss on marketable securities (26 ) (26 ) Net loss (62,056 ) (62,056 ) Balance at December 31, 2025 177,593,856 $ 338,808 10,614,231 1,074,089 $ $ 11,249 11,250 $ $ (228,340 ) $ (217,077 ) The accompanying notes are an integral part of these financial statements.

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Proceeds from issuance of Series C Preferred Stock, net of issuance costs 115,353 Net cash provided by financing activities 115,526 Net increase (decrease) in cash, cash equivalents and restricted cash 66,876 (23,074 ) Cash, cash equivalents and restricted cash at beginning of year 15,843 38,917 Cash, cash equivalents and restricted cash at end of year $ 82,719 $ 15,843 Supplemental Disclosure for Non-cash Activities Change in purchases of property and equipment included in accrued expenses (69 ) Non-cash adjustment to reduce right-of-use assets and lease liabilities due to lease termination The accompanying notes are an integral part of these financial statements.

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Note 6: Convertible Preferred Stock and Stockholders Deficit 7 changes

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Each share of convertible preferred stock will be automatically converted into common stock immediately upon (i) the closing of a firm commitment underwritten initial public offering at a price of at least $3.0358 $30.00 per share resulting in at least $50.0 million of gross proceeds to the Company or (ii) the approval, by vote or written consent, of the holders of a majority of the outstanding shares of preferred stock (voting together as a single class on an as-converted basis), together with the holders of a majority of shares of outstanding Series C preferred stock, and a majority of shares of outstanding Series B preferred stock.

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As of December 31, 2025, the total number of shares authorized under the Plan was 41,146,191, 4,163,709, and the number of shares available for issuance under the Plan was 1,994,970. 201,877.

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The aggregate fair value of shares vested during the year ended December 31, 2025 and 2024 was $2.2 million and $2.1 million, respectively. As of December 31, 2025, there were 10.5 1.1 million options vested and outstanding.

The weighted-average grant date fair value of emplo yee option grants during the years ended December 31, 2025 and 2024 was $0.73 $7.22 per share and $0.65 $6.43 per share, respectively .

In 2019, the Company amended the Plan to allow its directors and officers to early exercise their stock options by delivery of promissory notes, which provide the Company first-priority security interest in the underlying shares exercised through such promissory notes ( Promissory Notes ). In 2021 and 2022, certain directors and officers of the Company early exercised their stock options using Promissory Notes. These Promissory Notes accrue interest at a rate of 2% per year. For accounting purposes, Promissory Notes are treated as non-recourse as the Company does not intend to pursue cash collection in the event of default. Accordingly, the resulting exercises of the options were determined to be non-substantive, and the Company has not recorded the Promissory Notes or related accrued interest on its balance sheets. For this reason, the shares are not considered to be outstanding until the Promissory Notes are repaid. The principal balance and accrued interest of the Promissory Notes as of December 31, 2025 and 2024 was $2.3 million and $2.4 million, respectively. The number of shares subject to Promissory Notes was 6,153,610 622,707 and 6,359,063 643,494 as of December 31, 2025 and 2024, respectively.

In August 2024, an officer of the Company sold 497,000 50,293 shares of common stock to a preferred shareholder of the Company (the Buyer ) that were previously early exercised through a Promissory Note and paid the outstanding Promissory Note balance of $0.2 million to the Company. The amount paid by the Buyer in excess of fair value of the Company s common stock at the date of the sale was recorded to stock-based compensation expense during the year ended December 31, 2024.

In December 2024, the Company entered into an agreement to repurchase 1,945,000 196,821 shares of common stock for $1.6 million issued to the Chief Executive Officer and Director of the Company, which was used to cancel principal and interest of $1.6 million on an outstanding Promissory Note for the early exercise of stock options. Concurrently, the Company granted 1,945,000 196,820 new stock option awards with the same vesting terms. The transaction was considered an option modification under ASC 718, which was recorded to stock-based compensation expense during the year ended December 31, 2024.

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Note 8: Loan and Security Agreement 2 changes

1 unchanged paragraph

In connection with the Loan Agreement, the Company issued the Lender a warrant (the Lender Warrant ) to purchase 131,761 13,333 shares of the Company s common stock as of the date of the agreement at an exercise price of $0.78 $7,71 per share and expiring on December 20, 2032. The Company recorded $0.1 million as a component of additional paid-in capital within stockholders deficit upon issuing the Lender Warrant.

In November 2024, the Company entered into a Warrant Purchase Agreement with the Lender to allow for the purchase of 43,930 4,445 shares of common stock at an exercise price of $0.78 $7.71 per share. The Company recorded $34,000 as a component of additional paid-in capital within stockholders deficit related to the Lender Warrant.

1 unchanged paragraph

Legal proceedings 14 changes

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Convertible preferred stock, as converted

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For the financial statements as of and for the year ended December 31, 2025, the Company evaluated subsequent events through March 30, 2026, the date on which these financial statements were issued. The Company further evaluated subsequent events through October 26, 2026 and has determined that, other than the events described below, there were no further subsequent events requiring disclosure in these financial statements.

1 unchanged paragraph

On October 22, 2026, the board of directors and stockholders of the Company approved, and on October 23, 2026, the Company effected, a reverse stock split of the shares of the Company s outstanding common stock at a ratio of 1-for-9.8821 (the Reverse Stock Split ). The number of authorized shares and par value per share were not adjusted as a result of the Reverse Stock Split. All references to shares, options to purchase common stock, warrants, share amounts, per share amounts, and related information contained in the financial statements have been retrospectively adjusted to reflect the effect of the Reverse Stock Split for all periods presented. The shares of common stock underlying outstanding stock options and warrants were proportionately reduced, and the respective exercise prices were proportionately increased. In addition, the conversion ratios for each series of the Company s convertible preferred stock, which will convert into shares of common stock upon the closing of the Company s IPO, were proportionally adjusted.

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Common stock, $0.0001 par value; 228,898,561 shares authorized at June 30, 2026 and December 31, 2025; 17,118,449 1,732,276 and 16,767,841 1,696,796 shares issued at June 30, 2026 and December 31, 2025, respectively; 10,964,839 1,109,569 and 10,614,231 1,074,089 shares outstanding at June 30, 2026 and December 31, 2025, respectively Additional paid-in capital 13,854 11,249 13,855 11,250 Accumulated other comprehensive (loss) income (42 ) Accumulated deficit (264,886 ) (228,340 ) Total stockholders deficit (251,073 ) (217,077 ) Total liabilities, convertible preferred stock and stockholders deficit $ 110,275 $ 143,663 The accompanying notes are an integral part of these unaudited financial statements.

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Weighted-average shares used to calculate net loss per common share, basic and diluted 10,816,448 10,214,636 1,094,550 1,033,651 The accompanying notes are an integral part of these unaudited financial statements.

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Statements of Convertible Preferre d Stock and Stockholders Deficit (in thousands, except share data) (Unaudited) Convertible Preferred Stock Common Stock Additional Paid-in Accumulated Other Comprehensive Accumulated Total Stockholders Shares Amount Shares Amount Capital Income (Loss) Deficit Deficit Balance at December 31, 2025 177,593,856 $ 338,808 10,614,231 1,074,089 $ $ 11,249 11,250 $ $ (228,340 ) $ (217,077 ) Exercise of stock options 350,608 35,480 Stock-based compensation 2,483 2,483 Unrealized loss on marketable securities (55 ) (55 ) Net loss (36,546 ) (36,546 ) Balance at June 30, 2026 177,593,856 $ 338,808 10,964,839 1,109,569 $ $ 13,854 13,855 $ (42 ) $ (264,886 ) $ (251,073 ) Convertible Preferred Stock Common Stock Additional Paid-in Accumulated Other Comprehensive Accumulated Total Stockholders Shares Amount Shares Amount Capital Income (Loss) Deficit Deficit Balance at December 31, 2024 101,428,978 $ 223,480 10,023,079 1,014,267 $ $ 8,517 8,518 $ $ (166,284 ) $ (157,727 ) Exercise of stock options 77,928 7,886 Vesting of restricted stock 245,036 24,796 Stock-based compensation 1,220 1,220 Unrealized loss on marketable securities (32 ) (32 ) Net loss (31,759 ) (31,759 ) Balance at June 30, 2025 101,428,978 $ 223,480 10,346,043 1,046,949 $ $ 9,801 9,802 $ $ (198,043 ) $ (188,234 ) The accompanying notes are an integral part of these unaudited financial statements.

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Each share of convertible preferred stock will be automatically converted into common stock immediately upon (i) the closing of a firm commitment underwritten initial public offering at a price of at least $3.0358 $30.00 per share resulting in at least $50.0 million of gross proceeds to the Company or (ii) the approval, by vote or written consent, of the holders of a majority of the outstanding shares of preferred stock (voting together as a single class on an as-converted basis), together with the holders of a majority of shares of outstanding Series C preferred stock, and a majority of shares of outstanding Series B preferred stock.

3 unchanged paragraphs

As of June 30, 2026, the total number of shares authorized under the Plan was 42,146,191, 4,264,902, and the number of shares available for issuance under the Plan was 435,860. 44,106.

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The aggregate fair value of shares vested during the six months ended June 30, 2026 and 2025 was $1.8 million and $1.0 million, respectively. As of June 30, 2026, there were 13.3 1.3 million options vested and outstanding.

The weighted-average grant date fair value of emplo yee option grants during the six months ended June 30, 2026 and 2025 was $0.77 $7.57 per share and $0.71 $6.98 per share, respectively .

In 2019, the Company amended the Plan to allow its directors and officers to early exercise their stock options by delivery of promissory notes, which provide the Company first-priority security interest in the underlying shares exercised through such promissory notes ( Promissory Notes ). In 2021 and 2022, certain directors and officers of the Company early exercised their stock options using Promissory Notes. These Promissory Notes accrue interest at a rate of 2% per year. For accounting purposes, Promissory Notes are treated as non-recourse as the Company does not intend to pursue cash collection in the event of default. Accordingly, the resulting exercises of the options were determined to be non-substantive, and the Company has not recorded the Promissory Notes or related accrued interest on its balance sheets. For this reason, the shares are not considered to be outstanding until the Promissory Notes are repaid. The principal balance and accrued interest of the Promissory Notes was $2.4 million and $2.3 million as of June 30, 2026 and December 31, 2025, respectively. The number of shares subject to Promissory Notes was 6,153,610 622,707 as of June 30, 2026 and December 31, 2025.

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The AJ License Agreement contains additional customary representations and warranties, covenants, indemnifications and insurance and confidentiality provisions for agreements of its type. The AJ License Agreement may be terminated upon mutual consent of both parties. Unless terminated in accordance with its terms, the AJ License F- 39 Agreement continues until the expiration, revocation or invalidation of the last patents or the abandonment of the last patent application included within the licensed patents and technology.

10 unchanged paragraphs

In connection with the Loan Agreement, the Company issued the Lender a warrant (the Lender Warrant ) to purchase 131,761 13,333 shares of the Company s common stock as of the date of the agreement at an exercise price of $0.78 $7.71 per share and expiring on December 20, 2032. The Company recorded $0.1 million as a component of additional paid-in capital within stockholders deficit upon issuing the Lender Warrant.

In November 2024, the Company entered into a Warrant Purchase Agreement with the Lender to allow for the purchase of 43,930 4,445 shares of common stock at an exercise price of $0.78 $7.71 per share. The Company recorded $34,000 as a component of additional paid-in capital within stockholders deficit related to the Lender Warrant.

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Other Expenses of Issuance and Distribution 1 change

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* To be provided by amendment.

Recent Sales of Unregistered Securities 2 changes

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2. In conjunction with amending our line of credit with Lender, on November 15, 2024, we issued Lender a warrant to purchase a total of 43,930 4,445 shares of our common stock at an exercise price of $0.78. $7.71. The warrant contains a net exercise provision under which the Lender may, in lieu of payment of the exercise price in cash, surrender the warrant, and receive, a net amount of shares of our common stock based on the fair market value of our common stock at the time of the net exercise of the warrant after deduction of the aggregate exercise price. The warrant expire ten years from their date of issuance.

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From January 1, 2023 through the date of this registration statement, we granted stock options to purchase an aggregate of 23,727,000 2,401,007 shares of our common stock at a weighted-average exercise price of $0.70 $6.92 per share, to certain of our employees, consultants, and directors in connection with services provided to us by such persons. 1,729,873 176,679 of these options have been exercised and 1,913,867 193,669 have been canceled or forfeited or have expired through the date of this registration statement.

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Undertakings 3 changes

The undersigned registrant hereby undertakes to provide to the underwriters, at the closing specified in the underwriting agreement, certificates in such denominations and registered in such names as required by the underwriters to permit prompt delivery to each purchaser.

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Amended and Restated Certificate of Incorporation, as currently in effect 3.2+ Amended and Restated Bylaws, as currently in effect 3.3+ Form of Amended and Restated Certificate of Incorporation, to be effective immediately prior to the closing of this offering 3.4+ Form of Amended and Restated Bylaws, to be effective immediately prior to the closing of this offering 3.5 Certificate of Amendment to Amended and Restated Certificate of Incorporation, effective as of October 23, 2026 4.1+ Amended and Restated Investors Rights Agreement, dated October 1, 2025, by and among the Registrant and certain of its stockholders 5.1 Opinion of DLA Piper LLP (US) 10.1+# Aspen Neuroscience, Inc. 2018 Stock Plan 10.2+# Aspen Neuroscience, Inc. 2018 Stock Plan Form of Notice of Grant of Stock Option 10.3+# Aspen Neuroscience, Inc. 2018 Stock Plan Form of Stock Option Agreement 10.4+# Aspen Neuroscience, Inc. 2018 Stock Plan Form of Stock Option Exercise Notice 10.5# Aspen Neuroscience, Inc. 2026 Equity Incentive Plan 10.6+# Aspen Neuroscience, Inc. 2026 Equity Incentive Plan Form of Notice of Grant of Stock Option 10.7+# Aspen Neuroscience, Inc. 2026 Equity Incentive Plan Form of Stock Option Agreement 10.8+# Aspen Neuroscience, Inc. 2026 Equity Incentive Plan Form of Notice of Grant of Restricted Stock Units 10.9+# Aspen Neuroscience, Inc. 2026 Equity Incentive Plan Form of Restricted Stock Units Agreement 10.10# Aspen Neuroscience, Inc. 2026 Employee Stock Purchase Plan 10.11+# Aspen Neuroscience, Inc. 2026 Cash Incentive Plan 10.12# Aspen Neuroscience, Inc. Non-Employee Director Compensation Policy 10.13+# Aspen Neuroscience, Inc. Officer Severance and Change in Control Plan 10.14+# Executive Employment Agreement, dated effective as of January 18, 2021, by and between Damien McDevitt and the Registrant 10.15+# Employment Offer Letter, dated as of March 3, 2025, by and between Dalen Meeter and the Registrant 10.16+# Employment Offer Letter, dated as of May 18, 2022, by and between Kim Raineri and the Registrant II- 4 10.17+# Employment Offer Letter, dated as of July 21, 2026, by and between Faheem Hasnain and the Registrant II- 4 10.18+# Loan Forgiveness and Option Amendment Agreement, dated August 24, 2026, by and between Damien McDevitt and the Registrant 10.19+# Loan Forgiveness and Option Amendment Agreement, dated September 25, 2026, by and between Andrew Spaventa and the Registrant 10.20+# Loan Forgiveness and Option Amendment Agreement, dated September 25, 2026, by and between Faheem Hasnain and the Registrant 10.21+# Form of Indemnification Agreement for Directors and Officers 10.22+ Lease, dated as of March 27, 2019, by and between the Registrant and BMR-Road to the Cure LP 10.23+ First Amendment to Lease, dated as of June 10, 2021, by and between the Registrant and BMR-Road to the Cure LP 10.24+ Second Amendment to Lease, dated as of August 25, 2021, by and between the Registrant and BMR-Road to the Cure LP 10.25+ Third Amendment to Lease, dated as of May 18, 2023, by and between the Registrant and BMR-Road to the Cure LP 10.26+ Lease, dated as of May 12, 2021, by and between the Registrant and HCP TPSP, LLC 10.27+ Lease, dated as of August 20, 2026, by and between the Registrant and HCP Life Science REIT, Inc. 10.28+ Exclusive License Agreement, dated effective as of July 27, 2018, by and between the Registrant and The Scripps Research Institute and Summit for Stem Cell Foundation 10.29+ Assignment and Assumption Agreement, dated as of October 30, 2018, by and among the Registrant and Summit for Stem Cell Foundation, Mission Edge San Diego 10.30+ Non-Exclusive License Agreement, dated as of September 20, 2019, by and between the Registrant and iPS Academia Japan, Inc. 10.31+ License Agreement, dated effective as of December 5, 2023, by and between the Registrant and Sumitomo Pharma Co., Ltd. 10.32+ Collaboration and License Agreement, dated as of January 22, 2024, by and between the Registrant and Cell X Technologies, Inc. 10.33+ First Amendment to Collaboration and License Agreement, dated as of January 8, 2025, by and between the Registrant and Cell X Technologies, Inc. 10.34+ Second Amendment to Collaboration and License Agreement, dated as of October 28, 2025, by and between the Registrant and Cell X Technologies, Inc. 10.35+ Third Amendment to Collaboration and License Agreement, dated as of January 22, 2026, by and between the Registrant and Cell X Technologies, Inc. 10.36+ Fourth Amendment to Collaboration and License Agreement, dated as of April 6, 2026, by and between the Registrant and Cell X Technologies, Inc. 10.37+ Amended and Restated Collaboration and License Agreement, dated as of August 18, 2026, by and between the Registrant and Cell X Technologies, Inc. 10.38+ Side Letter Agreement, dated as of August 18, 2026, by and between the Registrant and Cell X Technologies, Inc. 10.39+ Secured Convertible Promissory Note Purchase Agreement, dated as of January 22, 2024, by and between the Registrant and Cell X Technologies, Inc. II- 5 10.40+ Secured Convertible Promissory Note, dated as of January 22, 2024, by and between the Registrant and Cell X Technologies, Inc. II- 5 10.41+ Exclusive License Agreement, dated as of August 18, 2026, by and between the Registrant and The Cleveland Clinic Foundation 10.42+ Master Supply Agreement, dated as of January 25, 2022, by and between the Registrant and ClearPoint Neuro, Inc. 10.43+ Main Services Agreement, dated as of September 16, 2024, by and between the Registrant and Mytos Bio Limited 10.44# Aspen Neuroscience, Inc. 2018 Stock Plan Form of Stock Option Agreement (Immediately Exercisable) 10.45# Equity Award Terms Amendment Agreement, dated as of November 26, 2025, by and between Damien McDevitt and the Registrant 23.1 Consent of Ernst & Young LLP, independent registered public accounting firm 23.2 Consent of DLA Piper LLP (US) (included in Exhibit 5.1) 24.1+ Power of Attorney (included on signature page) 107+ Filing Fee Table + Previously filed.

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Pursuant to the requirements of the Securities Act of 1933, the registrant has duly caused this registration statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of San Diego, State of California, on this 22 nd 26 th day of October, 2026.

14 unchanged paragraphs