Keros Therapeutics, Inc.

Previous wording

Our lead product candidate, rinvatercept (KER-065), is designed to bind to and inhibit TGF-ß ligands, including myostatin (GDF8) and activin A, which are negative regulators of muscle and bone mass and strength. Through inhibition of these TGF-ß ligands, we believe that rinvatercept has the potential to increase skeletal muscle regeneration, increase muscle size and strength, reduce body fat, reduce fibrosis of the skeletal muscle and increase bone strength. We are developing rinvatercept for the treatment of Duchenne muscular dystrophy, or DMD, and for the treatment of amyotrophic lateral sclerosis, or ALS. Glucocorticoids, the standard of care in DMD, can have significant side effects when used long-term, including catabolism of muscle, increased fat and accelerated bone loss. In March 2025, we announced initial topline results from the Phase 1 clinical trial of rinvatercept in healthy adult male volunteers. We have initiated a Phase 2 clinical trial of rinvatercept in patients with DMD, and expect to announce initial data from this trial in the first half of 2027. We also plan to engage regulators on the design of a Phase 2 clinical trial of rinvatercept in patients with ALS in the second half of 2026.

Current wording

Our lead product candidate, rinvatercept (KER-065), is designed to bind to and inhibit TGF-ß ligands, including myostatin (GDF8) and activin A, which are negative regulators of muscle and bone mass and strength. Through inhibition of these TGF-ß ligands, we believe that rinvatercept has the potential to increase skeletal muscle regeneration, increase muscle size and strength, reduce body fat, reduce fibrosis of the skeletal muscle and increase bone strength. We are developing rinvatercept for the treatment of Duchenne muscular dystrophy, or DMD, and for the treatment of amyotrophic lateral sclerosis, or ALS. Glucocorticoids, the standard of care in DMD, can have significant side effects when used long-term, including catabolism of muscle, increased fat and accelerated bone loss. In March 2025, we announced initial topline results from the Phase 1 clinical trial of rinvatercept in healthy adult male volunteers. We have commenced our Phase 2 clinical trial of rinvatercept in patients with DMD, and expect to announce initial data from this trial in the first half of 2027. We also plan to engage regulators on the design of a Phase 2 clinical trial of rinvatercept in patients with ALS in the second half of 2026.

Previous wording

Our most advanced product candidate, elritercept (KER-050), is an engineered ligand trap comprised of a modified ligand-binding domain of the TGF-ß receptor known as activin receptor type IIA, or ActRIIA, that is fused to the portion of the human antibody known as the Fc domain. Elritercept is being developed for the treatment of low blood cell counts, or cytopenias, including anemia and thrombocytopenia, in patients with myelodysplastic syndromes, or MDS, and in patients with myelofibrosis. In December 2024, we entered into an exclusive license agreement with Takeda Pharmaceuticals U.S.A., Inc., or Takeda, to further develop, manufacture and commercialize elritercept worldwide outside of mainland China, Hong Kong and Macau, which became effective on January 16, 2025. Elritercept is designed to increase red blood cell and platelet production by inhibiting the signaling of a subset of the TGF-ß family of proteins to promote hematopoiesis. We believe elritercept has the potential to provide benefit to patients suffering from red blood cell and platelet differentiation and maturation defects occurring across the spectrum from early through terminal stages of hematopoiesis, and consequently may be effective for many patients that have limited treatment options or are refractory to available therapies. In July 2025, we announced that the first patient was dosed in the placebo-controlled Phase 3 RENEW clinical trial in patients with very low-, low-, or intermediate-risk MDS, which we refer to as lower-risk MDS. The dosing of the first patient triggered a $10 million milestone payment to us under the license agreement with Takeda. In July 2026, we announced that the first patient was dosed in the open-label, randomized Phase 3 ELRiSE MDS clinical trial evaluating the efficacy and safety of elritercept versus epoetin alfa for the treatment of anemia due to very low, low, or intermediate risk MDS. The dosing of the first patient triggered a $20 million milestone payment payable to us under the license agreement with Takeda. We expect to distribute 25% of the net cash proceeds from this milestone payment to our stockholders following receipt of the payment.

Current wording

Our most advanced product candidate, elritercept (KER-050), is an engineered ligand trap comprised of a modified ligand-binding domain of the TGF-ß receptor known as activin receptor type IIA, or ActRIIA, that is fused to the portion of the human antibody known as the Fc domain. Elritercept is being developed for the treatment of low blood cell counts, or cytopenias, including anemia and thrombocytopenia, in patients with myelodysplastic syndromes, or MDS, and in patients with myelofibrosis. In December 2024, we entered into an exclusive license agreement with Takeda Pharmaceuticals U.S.A., Inc., or Takeda, to further develop, manufacture and commercialize elritercept worldwide outside of mainland China, Hong Kong and Macau, which became effective on January 16, 2025. Elritercept is designed to increase red blood cell and platelet production by inhibiting the signaling of a subset of the TGF-ß family of proteins to promote hematopoiesis. We believe elritercept has the potential to provide benefit to patients suffering from red blood cell and platelet differentiation and maturation defects occurring across the spectrum from early through terminal stages of hematopoiesis, and consequently may be effective for many patients that have limited treatment options or are refractory to available therapies. In July 2025, we announced that the first patient was dosed in the placebo-controlled Phase 3 RENEW clinical trial in patients with very low-, low-, or intermediate-risk MDS, which we refer to as lower-risk MDS. The dosing of the first patient triggered a $10 million milestone payment to us under the license agreement with Takeda. In July 2026, we announced that the first patient was dosed in the open-label, randomized Phase 3 ELRiSE MDS clinical trial evaluating the efficacy and safety of elritercept versus epoetin alfa for the treatment of anemia due to lower-risk MDS. The dosing of the first patient triggered a $20 million milestone payment payable to us under the license agreement with Takeda. In September 2026, we announced that the first patient was dosed in the double-blind, randomized Phase 3 ELRiSE MF clinical trial evaluating the efficacy and safety of elritercept to placebo in patients with myelofibrosis and anemia on concurrent ruxolitinib therapy. The dosing of the first patient triggered a $20 million milestone payment payable to us under the license agreement with Takeda. We plan to distribute 25% of the net cash proceeds we receive on or before December 31, 2028 from the license agreement with Takeda to our stockholders.

Previous wording

Since our inception in 2015, we have devoted the majority of our efforts to business planning, research and development of our product candidates, including by conducting clinical trials and preclinical studies, raising capital and recruiting management and technical staff to support these operations. To date, we have not generated any revenue from product sales as none of our product candidates have been approved for commercialization. We have historically financed our operations primarily through the sale of convertible preferred stock, common stock and cash received from licensing agreements.

Current wording

Since our inception in 2015, we have devoted the majority of our efforts to business planning, research and development of our product candidates, including by conducting clinical trials and nonclinical studies, raising capital and recruiting management and technical staff to support these operations. To date, we have not generated any revenue from product sales as none of our product candidates have been approved for commercialization. We have historically financed our operations primarily through the sale of convertible preferred stock, common stock and cash received from licensing agreements.

Previous wording

In December 2022, we filed a prospectus supplementto our registration statement on Form S-3ASR with the Securities and Exchange Commission, or the SEC, for the issuance and sale, if any, of up to $250.0 million of shares of our common stock pursuant to a sales agreement with Leerink Partners LLC, or Leerink, as sales agent, which we refer to as the ATM Sales Agreement, under which we may offer and sell, from time to time, shares of our common stock, or the ATM Shares, through Leerink, which we refer to as the ATM Offering. In May 2024, we filed a new registration statement on Form S-3ASR, which we refer to as the New Shelf Registration Statement, to replace the prior shelf registration statement that was set to expire, including a base prospectus, which became effective immediately upon filing, under which we could issue an unspecified amount of shares of our common stock, preferred stock, debt securities and warrants. In June 2024, we filed a prospectus supplement to the New Shelf Registration Statement for the issuance and sale, if any, of up to an additional$350.0 million of shares of our common stock under the ATM Sales Agreement. As of the filing of our Annual Report on Form 10-K for the year ended December 31, 2024, we no longer qualified as a well-known seasoned issuer and therefore were not eligible to use the New Shelf Registration Statement as an automatic shelf registration statement, and no shares were sold during the six months ended June 30, 2026.

Current wording

In May 2021, we entered into a Sales Agreement with Leerink Partners LLC, or Leerink, as sales agent, which we refer to as the ATM Sales Agreement, under which we may offer and sell, from time to time, shares of our common stock, or the ATM Shares, through Leerink, which we refer to as the ATM Offering. In September 2026, we filed a shelf registration statement on Form S-3 (File No. 333-298854) with the Securities and Exchange Commission, or the SEC, and a prospectus supplement, which registered the offering, issuance and sale of up to $350.0 million of various equity and debt securities, including the issuance and sale, if any, of up to $100.0 million of shares of our common stock under the ATM Sales Agreement pursuant to the prospectus supplement. The SEC declared the registration statement effective on September 16, 2026. During the three and nine months ended September 30, 2026, we did not sell any shares of our common stock pursuant to the ATM Offering.

Previous wording

Under the ATM Sales Agreement, Leerink may sell the ATM Shares by methods deemed to be an “at-the-market offering” as defined in Rule 415(a)(4) promulgated under the Securities Exchange Act of 1934, as amended. We may sell the ATM Shares in amounts and at times to be determined by us from time to time subject to the terms and conditions of the ATM Sales Agreement, but we have no obligation to sell any of the ATM Shares in the ATM Offering. As of June 30, 2026, we have sold a total of 4,290,096 shares of our common stock pursuant to the ATM Offering for aggregate net proceeds of approximately$228.6 million after deducting sales agent commissions and estimated offering expenses. As of June 30, 2026, we may not offer and sell any ATM shares.

Current wording

Under the ATM Sales Agreement, Leerink may sell the ATM Shares by methods deemed to be an “at-the-market offering” as defined in Rule 415(a)(4) promulgated under the Securities Act of 1933, as amended. We may sell the ATM Shares in amounts and at times to be determined by us from time to time subject to the terms and conditions of the ATM Sales Agreement, but we have no obligation to sell any of the ATM Shares in the ATM Offering. As of September 30, 2026, we had sold a total of 4,290,096 shares of our common stock pursuant to the ATM Offering for aggregate net proceeds of approximately$228.6 million after deducting sales agent commissions and estimated offering expenses. As of September 30, 2026, we may offer and sell ATM Shares at an aggregate offering price of up to $100.0 million (less any sales agent commissions) available under the ATM Offering.

Previous wording

On November 20, 2025, we disclosed that a total of 17,712,262 shares of our common stock were validly tendered and not validly withdrawn. In accordance with the terms and conditions of the Tender Offer, we accepted for purchase a total of 10,950,165 Tender Offer Shares at a purchase price of $17.75 per share, for an aggregate purchase price of approximately $194.4 million. As a result of the Tender Offer, we had 19,543,706 shares of common stock outstanding immediately following the closing of the Tender Offer.

Current wording

10,950,165 Tender Offer Shares at a purchase price of $17.75 per share, for an aggregate purchase price of approximately $194.4 million. As a result of the Tender Offer, we had 19,543,706 shares of common stock outstanding immediately following the closing of the Tender Offer.

Previous wording

We have incurred recurring operating losses each fiscal year through December 31, 2024. Our net income for the year ended December 31, 2025 was primarily driven by revenue related to the Takeda Agreement. Our ability to generate product revenue sufficient to achieve profitability will depend on the successful development and commercialization of one or more of our product candidates. Our net loss was $28.7 million and$52.4 millionfor thethree and six months ended June 30, 2026. As of June 30, 2026, we had an accumulated deficit of $534.2 million. We expect to continue to generate operating losses and negative operating cash flows for the foreseeable future in connection with our ongoing activities. As of June 30, 2026, we had cash and cash equivalents of$257.6 million.

Current wording

We have incurred recurring operating losses each fiscal year through December 31, 2024. Our net income for the year ended December 31, 2025 was primarily driven by revenue related to the Takeda Agreement. Our ability to generate product revenue sufficient to achieve profitability will depend on the successful development and commercialization of one or more of our product candidates. We had net income of $14.2 million for thethree months ended September 30, 2026, which was primarily driven by the achievement of two milestones related to our Takeda Agreement. Our net loss was$38.3 millionfor thenine months ended September 30, 2026. As of September 30, 2026, we had an accumulated deficit of $520.0 million. We expect to continue to generate operating losses and negative operating cash flows for the foreseeable future in connection with our ongoing activities. As of September 30, 2026, we had cash and cash equivalents of$259.5 million.

Previous wording

Recent trends towards rising inflation and prices may materially affect our business and corresponding financial position and cash flows. Inflationary factors, such as increases in the cost of materials and supplies relating to our preclinical studies, clinical trials, interest rates and overhead costs may adversely affect our operating results. Rising interest rates and implementation of tariffs present a recent challenge impacting the U.S. economy and could make it more difficult for us to obtain traditional financing on acceptable terms, if at all, in the future. Additionally, the general consensus among economists suggests that we should expect a higher recession risk to continue over the next year due in part to ongoing tariff and trade issues, which, together with the foregoing, could result in further economic uncertainty and volatility in the capital markets in the near term, and could negatively affect our operations. Furthermore, such economic conditions have produced downward pressure on share prices. Although we do not believe that inflation, higher interest rates or tariffs have had a material impact on our financial position or results of operations to date, we may experience increases in the near future (especially if inflation rates rise more quickly) on our operating costs, including our labor costs and research and development costs, due to supply chain constraints, consequences associated with public health crises and global geopolitical tensions, such as the ongoing war between Russia and Ukraine and the wars in the Middle East, worsening global macroeconomic conditions and employee availability and wage increases, which may result in additional stress on our working capital resources.

Current wording

Recent trends towards rising inflation and prices may materially affect our business and corresponding financial position and cash flows. Inflationary factors, such as increases in the cost of materials and supplies relating to our nonclinical studies, clinical trials, interest rates and overhead costs may adversely affect our operating results. Rising interest rates and implementation of tariffs present a recent challenge impacting the U.S. economy and could make it more difficult for us to obtain traditional financing on acceptable terms, if at all, in the future. Additionally, the general consensus among economists suggests that we should expect a higher recession risk to continue over the next year due in part to ongoing tariff and trade issues, which, together with the foregoing, could result in further economic uncertainty and volatility in the capital markets in the near term, and could negatively affect our operations. Furthermore, such economic conditions have produced downward pressure on share prices. Although we do not believe that inflation, higher interest rates or tariffs have had a material impact on our financial position or results of operations to date, we may experience increases in the near future (especially if inflation rates rise more quickly) on our operating costs, including our labor costs and research and development costs, due to supply chain constraints, consequences associated with public health crises and global geopolitical tensions, such as the ongoing war between Russia and Ukraine and the wars in the Middle East, worsening global macroeconomic conditions and employee availability and wage increases, which may result in additional stress on our working capital resources.

Previous wording

Pursuant to the terms of the Takeda Agreement, we received a $200.0 million upfront payment in February 2025. In July 2025, we announced that the first patient was dosed in the Phase 3 RENEW clinical trial of elritercept, which triggered a $10 million milestone payment to us under the Takeda Agreement. We received the $10.0 million payment for the achievement of this development milestone in August 2025. In addition to the upfront payment and milestone payment, we are entitled to receive up to an aggregate of (i) $80.0 million upon the achievement of specified development milestones, (ii) $280.0 million upon the achievement of specified commercial milestones and (iii) $740.0 million upon the achievement of specified sales milestones. If a licensed product is approved for marketing in the Takeda Territory, we will be entitled to receive royalty payments based on tiered increments of annual net sales in the Takeda Territory, with such percentage ranging from the low double-digits to high teens, subject to specified potential royalty reductions.

Current wording

MF clinical trial, which triggered a one-time $20.0 million milestone payment payable to us under the Takeda Agreement. We have not received the payment for this milestone as of September 30, 2026. In addition to the upfront payment and milestone payments, we are entitled to receive up to an aggregate of (i) $40.0 million upon the achievement of specified development milestones, (ii) $280.0 million upon the achievement of specified commercial milestones and (iii) $740.0 million upon the achievement of specified sales milestones. If a licensed product is approved for marketing in the Takeda Territory, we will be entitled to receive royalty payments based on tiered increments of annual net sales in the Takeda Territory, with such percentage ranging from the low double-digits to high teens, subject to specified potential royalty reductions.

Previous wording

Pursuant to the terms of the Hansoh Agreement, we received a net $18.0 million upfront payment in January 2022. In addition to the upfront payment and development milestones achieved to date, we are entitled to receive up to an aggregate of (i) $23.5 million upon the achievement of specified development milestones and (ii) $144.0 million upon the achievement of specified net sales thresholds for all licensed products in the Hansoh Territory. If a licensed product is approved for marketing in the Hansoh Territory, we will be entitled to receive royalty payments based on a tiered percentage of annual net sales in each region within the Hansoh Territory, with such percentage ranging from the low double digit to high teens, subject to specified potential royalty reductions. We did not recognize any revenue related to milestones for the three and six months ended June 30, 2026 or 2025.

Current wording

Pursuant to the terms of the Hansoh Agreement, we received a net $18.0 million upfront payment in January 2022. In addition to the upfront payment and development milestones achieved to date, we are entitled to receive up to an aggregate of (i) $23.5 million upon the achievement of specified development milestones and (ii) $144.0 million upon the achievement of specified net sales thresholds for all licensed products in the Hansoh Territory. If a licensed product is approved for marketing in the Hansoh Territory, we will be entitled to receive royalty payments based on a tiered percentage of annual net sales in each region within the Hansoh Territory, with such percentage ranging from the low double digit to high teens, subject to specified potential royalty reductions. We did not recognize any revenue related to milestones for the three and nine months ended September 30, 2026 or 2025.

Previous wording

Effective in June 2023, in connection with the Hansoh Agreement, we entered into a manufacturing technology transfer agreement, or the Tech Transfer Agreement, with Hansoh. The Tech Transfer Agreement governs the transfer to Hansoh of all documents and information required to complete the manufacturing technology transfer. Under the Tech Transfer Agreement, Hansoh is obligated to make certain payments to us, at the rates set forth in the Tech Transfer Agreement, as manufacturing technology transfer services are provided over the term of the Tech Transfer Agreement. We did not recognize any revenue during the three and six months ended June 30, 2026. We recognized zero and $0.1 million of service and other revenue during the three and six months ended June 30, 2025, respectively.

Current wording

Effective in June 2023, in connection with the Hansoh Agreement, we entered into a manufacturing technology transfer agreement, or the Tech Transfer Agreement, with Hansoh. The Tech Transfer Agreement governs the transfer to Hansoh of all documents and information required to complete the manufacturing technology transfer. Under the Tech Transfer Agreement, Hansoh is obligated to make certain payments to us, at the rates set forth in the Tech Transfer Agreement, as manufacturing technology transfer services are provided over the term of the Tech Transfer Agreement. We did not recognize any revenue during the three and nine months ended September 30, 2026. We recognized zero and $0.1 million of service and other revenue during the three and nine months ended September 30, 2025, respectively.

Previous wording

Effective in February 2024, in connection with the Hansoh Agreement, we entered into a clinical product supply agreement with Hansoh, or the Supply Agreement. We recognized zero and $0.3 million of service and other revenue during the three and six months ended June 30, 2026, respectively. We did not recognize any revenue during the three and six months ended June 30, 2025.

Current wording

Effective in February 2024, in connection with the Hansoh Agreement, we entered into a clinical product supply agreement with Hansoh, or the Supply Agreement. We recognized zero and $0.3 million of service and other revenue during the three and nine months ended September 30, 2026, respectively. We recognized $0.1 million of service and other revenue during the three and nine months ended September 30, 2025.

Previous wording

In April 2016, we entered into an exclusive patent license agreement with The General Hospital Corporation, or MGH, and such agreement was subsequently amended in May 2017 and February 2018. Under the license agreement with MGH, or the MGH Agreement, we obtained an exclusive, worldwide license, with the right to sublicense, under certain patents and technical information of MGH, to make, have made, use, have used, sell, have sold, lease, have leased, import, have imported or otherwise transfer licensed products and processes for use in the treatment, diagnosis, palliation and prevention of diseases and disorders in humans and animals. We are required to use commercially reasonable efforts to develop and commercialize licensed products and processes, and must achieve certain required diligence milestones.

Current wording

MGH Agreement, we obtained an exclusive, worldwide license, with the right to sublicense, under certain patents and technical information of MGH, to make, have made, use, have used, sell, have sold, lease, have leased, import, have imported or otherwise transfer licensed products and processes for use in the treatment, diagnosis, palliation and prevention of diseases and disorders in humans and animals. We are required to use commercially reasonable efforts to develop and commercialize licensed products and processes, and must achieve certain required diligence milestones.

Previous wording

Research and development expenses consist primarily of costs incurred for our research activities, including our discovery efforts and the preclinical and clinical development of our current and potential future product candidates, and include:

Current wording

Research and development expenses consist primarily of costs incurred for our research activities, including our discovery efforts and the nonclinical and clinical development of our current and potential future product candidates, and include:

Previous wording

▪expenses incurred under agreements with third parties, including CROs that conduct research, preclinical and clinical activities on our behalf, as well as contract manufacturing organizations, or CMOs, that manufacture drug product for use in our preclinical studies and clinical trials;

Current wording

▪expenses incurred under agreements with third parties, including CROs that conduct research, nonclinical and clinical activities on our behalf, as well as contract manufacturing organizations, or CMOs, that manufacture drug product for use in our nonclinical studies and clinical trials;

Previous wording

General and administrative expenses consist primarily of salaries and other related costs, including stock-based compensation for personnel in our executive, finance, corporate and business development and administrative functions. General and administrative expenses also include professional fees for legal, patent, accounting, information technology, auditing, tax and consulting services, and travel expenses and facility-related expenses, which include direct depreciation costs and allocated expenses for rent and maintenance of facilities and other operating costs.

Current wording

General and administrative expenses consist primarily of salaries and other related costs, including stock-based compensation, for personnel in our executive, finance, corporate and business development and administrative functions. General and administrative expenses also include professional fees for legal, patent, accounting, information technology, auditing, tax and consulting services, travel expenses and facility-related expenses, which include direct depreciation costs and allocated expenses for rent and maintenance of facilities and other operating costs.

Previous wording

The tax (provision) benefit has historically resulted from income tax related to taxable income generated from the Takeda Agreement. We have not recorded any income tax benefits for the losses incurred to date as it is more likely than not that these benefits will not be realized based on our history of losses and expected future losses.

Current wording

The income tax (provision) benefit has historically resulted from income tax related to taxable income generated from the Takeda Agreement. We have not recorded any income tax benefits for the losses incurred to date as it is more likely than not that these benefits will not be realized based on our history of losses and expected future losses.

Previous wording

June 30, 2025. The decrease in total revenue of $229.0 million was primarily due to recognition of license revenue under the Takeda Agreement during the six months ended June 30, 2025.

Current wording

We recognized $9.0 thousand of service and other revenue related to the transition services agreement with Takeda, or the TSA, and $40.0 million of license revenue related to the achievement of two development milestones under the Takeda Agreement for the three months ended September 30, 2026, compared to $4.3 million of service and other revenue primarily related to the TSA, and $10.0 million of license revenue related to the achievement of a development milestone under the Takeda Agreementfor thethree months ended September 30, 2025. The increase in total revenue of $25.7 million was primarily due to recognition of license revenue for the two development milestones achieved under the Takeda Agreement during the three months ended September 30, 2026.

Previous wording

Research and development expenses were $22.3 million for the three months ended June 30, 2026, compared to $43.5 million for the three months ended June 30, 2025. The decrease of $21.2 million was primarily due to (i) a decrease of $15.6 million of elritercept-related expenses, primarily driven by a decrease of $11.1 million in clinical spend and a decrease of $4.5 million in manufacturing activities as activities transitioned to Takeda during 2025; (ii) a decrease of $3.8 million of cibotercept- related expenses, primarily driven by a decrease of $2.2 million in clinical spend associated with our terminated Phase 2 clinical trial and a decrease of $1.6 million in manufacturing and preclinical activities; (iii) a decrease of $7.7 million related to personnel expenses, including a decrease of $2.5 million of stock-based compensation costs, driven by a reduction in headcount; and (iv) a net decrease of $0.9 million in facilities, supplies, professional fees and other expenses. These decreases were partially offset by (a) an increase of $2.7 million of rinvatercept-related expenses, primarily driven by an increase of $1.6 million in clinical spend associated with our Phase 2 clinical trial in patients with DMD and our planned Phase 2 clinical trial in patients with ALS and an increase of $1.1 million in manufacturing and preclinical activities; and (b) an increase of $4.1 million in preclinical pipeline and development activities. We expect research and development expenses to fluctuate from quarter to quarter depending on the timing of clinical trial activities, clinical manufacturing and other development activities.

Current wording

Research and development expenses were $20.5 million for the three months ended September 30, 2026, compared to $19.5 million for the three months ended September 30, 2025. The increase of $1.0 million was primarily due to (i) an increase of $3.7 million of rinvatercept-related expenses, primarily driven by an increase of $1.9 million in manufacturing and nonclinical activities and an increase of $1.8 million in clinical spend associated with our Phase 2 clinical trial in patients with DMD and our planned Phase 2 clinical trial in patients with ALS; and (ii) an increase of $2.7 million in nonclinical pipeline and development activities. These increases were partially offset by (a) a decrease of $3.3 million of elritercept-related expenses as activities transitioned to Takeda during 2025; (b) a decrease of $1.4 million of cibotercept-related expenses related to our deprioritization of cibotercept; and (c) a decrease of $0.7 million related to personnel expenses, primarily driven by a net decrease of $1.7 million in salaries, severance, bonus and retention bonus and partially offset by an increase of $1.0 million of stock-based compensation costs. We expect research and development expenses to fluctuate from quarter to quarter depending on the timing of clinical trial activities, clinical manufacturing and other development activities.

Previous wording

General and administrative expenses were $8.6 million for the three months ended June 30, 2026, compared to $14.5 million for the three months ended June 30, 2025. The decrease of approximately $5.9 million was primarily due to (i) a net decrease of$4.3 million in professional fees, insurance, facilities, supplies and other expenses; and (ii) adecrease of $1.6 million in personnel expenses, which includes a decrease of$0.7 million of stock-based compensation costs.

Current wording

General and administrative expenses were $6.7 million for the three months ended September 30, 2026, compared to $10.1 million for the three months ended September 30, 2025. The decrease of approximately $3.4 million was primarily due to (i) a net decrease of$1.7 million in professional fees, insurance, facilities, supplies and other expenses; and (ii) adecrease of $1.7 million in personnel expenses, which includes a decrease of$0.8 million of stock-based compensation costs.

Previous wording

Total other income, net was $2.2 million for the three months ended June 30, 2026, comparedto $6.9 million for the three months ended June 30, 2025. The decrease of $4.7 million was driven by a decrease of $4.8 million in dividend income, partially offset by a decrease of $0.2 million in other expense, net.

Current wording

Total other income, net was $2.1 million for the three months ended September 30, 2026, comparedto $6.7 million for the three months ended September 30, 2025. The decrease of $4.6 million was primarily driven by a decrease of $4.7 million in dividend income.

Previous wording

Income tax provision was zero for thethree months ended June 30, 2026, compared to an income tax benefit of $2.2 million for thethree months ended June 30, 2025. The income tax benefit in 2025 was attributable to taxable income generated from the Takeda Agreement.

Current wording

Income tax provision was $0.8 million for the three months ended September 30, 2026, compared to an income tax benefit of $1.4 million for the three months ended September 30, 2025. The prior period benefit was driven by deductible expenses incurred that reduced the taxable liability associated with the Takeda Agreement.

Previous wording

The following table summarizes our research and development expenses for the six months ended June 30, 2026 and 2025 (in thousands):

Current wording

The following table summarizes our research and development expenses for the nine months ended September 30, 2026 and 2025 (in thousands):

Previous wording

Research and development expenses were $38.4 million for the six months ended June 30, 2026, compared to $92.2 million for the six months ended June 30, 2025. The decrease of $53.8 million was primarily due to (i) a decrease of $34.5 million of elritercept-related expenses, primarily driven by a decrease of $21.1 million in clinical spend and a decrease of $13.4 million in manufacturing activities as activities transitioned to Takeda during 2025; (ii) a decrease of $10.0 million of cibotercept-related expenses, primarily driven by a decrease of $6.3 million in clinical spend associated with our terminated Phase 2 clinical trial and a decrease of $3.7 million in manufacturing and preclinical activities; (iii) a decrease of $15.6 million related to personnel expenses, including a decrease of $5.5 million of stock-based compensation costs, driven by a reduction in headcount; and (iv) a net decrease of $1.8 million in facilities, supplies, professional fees and other expenses. These decreases were partially offset by (a) an increase of $3.8 million of rinvatercept-related expenses, primarily driven by an increase of $3.1 million in clinical spend associated with our Phase 2 clinical trial in patients with DMD and our planned Phase 2 clinical trial in patients with ALS, and a net increase of $0.7 million in manufacturing and preclinical activities; and (b) an increase of $4.4 million in preclinical pipeline and development activities. We expect research and development expenses to fluctuate from quarter to quarter depending on the timing of clinical trial activities, clinical manufacturing and other development activities.

Current wording

Research and development expenses were $58.9 million for the nine months ended September 30, 2026, compared to $111.7 million for the nine months ended September 30, 2025. The decrease of $52.8 million was primarily due to (i) a decrease of $37.9 million of elritercept-related expenses as activities transitioned to Takeda during 2025; (ii) a decrease of $11.4 million of cibotercept-related expenses related to our deprioritization of cibotercept; (iii) a decrease of $16.3 million related to personnel expenses, including a decrease of $4.4 million of stock-based compensation costs, driven by a reduction in headcount; and (iv) a net decrease of $1.8 million in facilities, supplies, professional fees and other expenses. These decreases were partially offset by (a) an increase of $7.5 million of rinvatercept-related expenses, primarily driven by an increase of $4.9 million in clinical spend associated with our Phase 2 clinical trial in patients with DMD and our planned Phase 2 clinical trial in patients with ALS, and a net increase of $2.6 million in manufacturing and nonclinical activities; and (b) an increase of $7.1 million in nonclinical pipeline and development activities. We expect research and development expenses to fluctuate from quarter to quarter depending on the timing of clinical trial activities, clinical manufacturing and other development activities.

Previous wording

General and administrative expenses were $18.8 million for the six months ended June 30, 2026, compared to $25.0 million for the six months ended June 30, 2025. The decrease of approximately $6.2 million was primarily due to a (i) net decrease of $4.3 million in professional fees, insurance, facilities, supplies and other expenses; and (ii) a decrease of $1.9 million in personnel expenses, which includes a decrease of $0.4 million of stock-based compensation costs.

Current wording

General and administrative expenses were $25.5 million for the nine months ended September 30, 2026, compared to $35.1 million for the nine months ended September 30, 2025. The decrease of approximately $9.7 million was primarily due to (i) a net decrease of $6.0 million in professional fees, insurance, facilities, supplies and other expenses; and (ii) a decrease of $3.6 million in personnel expenses, which included a decrease of $1.2 million of stock-based compensation costs.

Previous wording

Total other income, net was $4.4 million for the six months ended June 30, 2026, compared to $13.4 million for the six months ended June 30, 2025. The decrease of $9.0 million was driven by a decrease of $9.3 million in dividend income, partially offset by a decrease of $0.3 million in other expense, net.

Current wording

Total other income, net was $6.5 million for the nine months ended September 30, 2026, compared to $20.0 million for the nine months ended September 30, 2025. The decrease of $13.5 million was driven by a decrease of $14.0 million in dividend income, partially offset by (i) a decrease of $0.4 million in other expense, net and (ii) an increase of $0.1 million in interest income, net.

Previous wording

June 30, 2025, which was primarily driven by the one-time upfront fee related to the Takeda Agreement. As of June 30, 2026 and December 31, 2025, we had an accumulated deficit of $534.2 million and $481.8 million, respectively. To date, we have devoted the majority of our efforts to business planning, research and development of our product candidates, including by conducting clinical trials and preclinical studies, raising capital and recruiting management and technical staff to support these operations. Our primary uses of cash are to fund operating expenses, which are primarily research and development expenditures. We expect to continue to incur substantial expenses in connection with our ongoing activities, particularly as we advance the preclinical studies and clinical trials of our product candidates. Furthermore, we expect to incur costs associated with operating as a public company, including significant legal, accounting, investor relations, director and officer insurance premiums and other expenses. In addition, if we obtain marketing approval for any of our product candidates, we expect to incur significant commercialization expenses related to establishing sales, marketing, distribution and other commercial infrastructure to commercialize such products.

Current wording

Since our inception, we have incurred significant operating losses each fiscal year through December 31, 2024. Our net income for the year ended December 31, 2025 was primarily driven by revenue related to the Takeda Agreement. Our net loss was $38.3 million for the nine months ended September 30, 2026 compared to net income of $110.5 million for the nine months ended September 30, 2025, which was primarily driven by the one-time upfront fee related to the Takeda Agreement. As of September 30, 2026 and December 31, 2025, we had an accumulated deficit of $520.0 million and $481.8 million, respectively. To date, we have devoted the majority of our efforts to business planning, research and development of our product candidates, including by conducting clinical trials and nonclinical studies, raising capital and recruiting management and technical staff to support these operations. Our primary uses of cash are to fund operating expenses, which are primarily research and development expenditures. We expect to continue to incur substantial expenses in connection with our ongoing activities, particularly as we advance the nonclinical studies and clinical trials of our product candidates. Furthermore, we expect to incur costs associated with operating as a public company, including significant legal, accounting, investor relations, director and officer insurance premiums and other expenses. In addition, if we obtain marketing approval for any of our product candidates, we expect to incur significant commercialization expenses related to establishing sales, marketing, distribution and other commercial infrastructure to commercialize such products.

Previous wording

In December 2022, we filed a prospectus supplement to a registration statement on Form S-3ASR, including a base prospectus and sales agreement prospectus, or the Prior Shelf Registration Statement, for the issuance and sale of up to $250.0 million of shares of our common stock. On May 3, 2024, we filed a new registration statement on Form S-3ASR, or the New Shelf Registration Statement, to replace the Prior Shelf Registration Statement that was set to expire, which became automatically effective upon filing, and which permitted us to offer, from time to time, an unspecified amount of common stock, preferred stock, debt securities and warrants, including through an “at the market” program with Leerink, as sales agent, or the ATM Program. As of the filing of our Annual Report on Form 10-K for the year ended December 31, 2024, we were no longer qualified as a well-known seasoned issuer and therefore were not eligible to use the New Shelf Registration Statement as an automatic shelf registration statement. As of June 30, 2026, we have sold a total of 4,290,096 shares of our common stock pursuant to the ATM Program. As of June 30, 2026, we were not eligible to offer and sell any shares of our common stock under the ATM Program and did not sell any shares during the three months ended June 30, 2026.

Current wording

In September 2026, we filed a shelf registration statement on Form S-3 with the SEC and a prospectus supplement, which registered the offering, issuance and sale of up to $350.0 million of various equity and debt securities, including the issuance and sale, if any, of up to $100.0 million of shares of our common stock under the ATM Sales Agreement pursuant to the prospectus supplement. The SEC declared the registration statement effective on September 16, 2026. As of September 30, 2026, we had sold a total of 4,290,096 shares of our common stock pursuant to the ATM Offering. During the three and nine months ended September 30, 2026, we did not sell any shares of our common stock pursuant to the ATM Offering. As of September 30, 2026, we may offer and sell ATM Shares at an aggregate offering price of up to $100.0 million (less any sales agent commissions) available under the ATM Offering.

Previous wording

As of June 30, 2026, we had cash and cash equivalents of $257.6 million. Based on our current operating assumptions, we believe that our existing cash and cash equivalents will be sufficient to fund our projected liquidity requirements into the first 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 currently expect. Due to the numerous risks and uncertainties associated with the development of our product candidates and programs, and because the extent to which we may enter into collaborations with third parties for development of our product candidates is unknown, we are unable to estimate the timing and amounts of increased capital outlays and operating expenses associated with completing the research and development of our product candidates. Our future funding requirements, both near and long-term, will depend on many factors, including:

Current wording

As of September 30, 2026, we had cash and cash equivalents of $259.5 million. Based on our current operating assumptions, we believe that our existing cash and cash equivalents will be sufficient to fund our projected liquidity requirements 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 currently expect. Due to the numerous risks and uncertainties associated with the development of our product candidates and programs, and because the extent to which we may enter into collaborations with third parties for development of our product candidates is unknown, we are unable to estimate the timing and amounts of increased capital outlays and operating expenses associated with completing the research and development of our product candidates. Our future funding requirements, both near and long-term, will depend on many factors, including:

Previous wording

•the progress, timing and completion of preclinical studies and clinical trials for our current or any future product candidates, as well as the associated costs, including any unforeseen costs we may incur as a result of preclinical study or clinical trial delays due to public health crises or other causes;

Current wording

•the progress, timing and completion of nonclinical studies and clinical trials for our current or any future product candidates, as well as the associated costs, including any unforeseen costs we may incur as a result of nonclinical study or clinical trial delays due to public health crises or other causes;

Previous wording

•the need for additional or expanded preclinical studies and clinical trials beyond those that we plan to conduct with respect to our current and future product candidates;

Current wording

•the need for additional or expanded nonclinical studies and clinical trials beyond those that we plan to conduct with respect to our current and future product candidates;

Previous wording

The following table summarizes our cash flows for the six months ended June 30, 2026 and 2025 (in thousands):

Current wording

The following table summarizes our cash flows for the nine months ended September 30, 2026 and 2025 (in thousands):

Previous wording

Net cash used in operating activities was $24.0 million for the six months ended June 30, 2026, which was driven by a net loss of $52.4 million and partially offset by (i) $14.8 million in net cash provided by operating assets and liabilities; and (ii) non-cash charges including $11.6 million of stock-based compensation expense, $1.3 million in lease expenses and $0.8 million in depreciation. The $14.8 million of net cash provided by operating assets and liabilities was comprised of (i) a $15.2 million decrease in prepaid expenses and other current assets due to timing of expense recognition for our research and development costs; and (ii) a $3.6 million decrease in accounts receivable related to the Takeda Agreement, which was partially offset by (a) a $2.8 million decrease in accounts payable and accrued expenses; and (b) a $1.2 million change in operating lease liabilities.

Current wording

Net cash used in operating activities was $20.6 million for the nine months ended September 30, 2026, which was driven by (i) a net loss of $38.3 million; and (ii) $1.2 million in net cash used in operating assets and liabilities, partially offset by non-cash charges including $15.8 million of stock-based compensation expense, $2.0 million in lease expenses and $1.2 million in depreciation. The $1.2 million of net cash used in operating assets and liabilities was comprised of (i) a $16.4 million increase in accounts receivable related to the Takeda Agreement; and (ii) a $1.8 million change in operating lease liabilities, which was partially offset by (a) a $16.3 million decrease in prepaid expenses and other current assets due to timing of expense recognition for our research and development costs; (b) a $0.1 million increase in accounts payable and accrued expenses; and (c) a $0.6 million increase in current tax liability.

Previous wording

Net cash provided by operating activities was $131.5 million for the six months ended June 30, 2025, which was driven by a (i) net income of $117.8 million and (ii) non-cash charges including $17.4 million of stock-based compensation expense, $1.2 million in lease expenses and $0.7 million in depreciation; partially offset by $5.5 million in net cash used in operating assets and liabilities. The $5.5 million of net cash used in operating assets and liabilities was comprised of (i) a $13.1 million increase in accounts receivable related to the Takeda Agreement; (ii) a $0.6 million increase in prepaid expenses and other current assets due to timing of expense recognition for our research and development costs; (iii) a $0.3 million decrease in accounts payable and accrued expenses to support the advancement of our programs; and (iv) a $0.9 million change in operating lease liabilities, which was partially offset by; (a) a $0.9 million increase in deferred revenue; (b) a $6.3 million increase in current tax liability; and (c) a $2.1 million decrease in other long-term assets.

Current wording

Net cash provided by operating activities was $134.8 million for the nine months ended September 30, 2025, which was driven by (i) net income of $110.5 million; (ii) $48.0 thousand in net cash provided by operating assets and liabilities; and (iii) non-cash charges including $21.4 million of stock-based compensation expense, $1.8 million in lease expenses and $1.1 million in depreciation. The $48.0 thousand of net cash provided by operating assets and liabilities was comprised of (i) a $4.1 million increase in current tax liability; (ii) a $3.9 million decrease in prepaid expenses and other current assets due to timing of expense recognition for our research and development costs; (iii) a $2.1 million decrease in other long-term assets; and (iv) a $0.2 million increase in deferred revenue; offset by (a) an $8.0 million decrease in accounts payable and accrued expenses to support the advancement of our programs, primarily driven by the transition of elritercept-related expenses to Takeda and the deprioritization of cibotercept, (b) a $1.4 million change in operating lease liabilities; and (c) a $0.8 million increase in accounts receivable related to the Takeda Agreement.

Previous wording

Net cash used in investing activities was $0.2 million for the six months ended June 30, 2026 and $1.3 million for the six months ended June 30, 2025. The cash used in investing activities in both periods was due to purchases of property and equipment.

Current wording

Net cash used in investing activities was $0.3 million for the nine months ended September 30, 2026 and $1.4 million for the nine months ended September 30, 2025. The cash used in investing activities in both periods was due to purchases of property and equipment.

Previous wording

Net cash used in financing activities was $5.6 million for the six months ended June 30, 2026, which was primarily related to $5.7 million in cash paid for direct expenses associated with the Repurchase Agreements and the Tender Offer, partially offset by exercises of options to purchase common stock.

Current wording

Net cash used in financing activities was $7.1 million for the nine months ended September 30, 2026, which was primarily related to (i) $5.7 million in cash paid for direct expenses associated with the Repurchase Agreements and the Tender Offer, and (ii) $1.5 million used to repurchase shares of common stock via the September 2026 share repurchase program, partially offset by issuances of common stock under the 2020 Employee Stock Purchase Plan and exercises of options to purchase common stock.

Previous wording

Net cash provided by financing activities was nominal for the six months ended June 30, 2025 and was related to exercises of options to purchase common stock.

Current wording

Net cash provided by financing activities was $0.2 million for the nine months ended September 30, 2025 and was primarily related to issuances of common stock under the 2020 Employee Stock Purchase Plan and exercises of options to purchase common stock.

Previous wording

We enter into agreements in the normal course of business with contract manufacturing organizations for process development, raw material purchases and manufacturing services. These contracts typically do not contain minimum purchase commitments and are generally cancellable by us upon written notice. Payments due upon cancellation consist of payments for services provided or expenses incurred, including noncancellable obligations of our service providers, up to the date of cancellation and, in the case of certain arrangements with contract manufacturing organizations, may include noncancellable fees. Under such agreements, the exact amounts owed by us in the event of termination will be based on the timing of the termination and the exact terms of the agreement. As of June 30, 2026, we have committed up to approximately $7.0 million under these agreements which are expected to be paid through 2028.

Current wording

We enter into agreements in the normal course of business with contract manufacturing organizations for process development, raw material purchases and manufacturing services. These contracts typically do not contain minimum purchase commitments and are generally cancellable by us upon written notice. Payments due upon cancellation consist of payments for services provided or expenses incurred, including noncancellable obligations of our service providers, up to the date of cancellation and, in the case of certain arrangements with contract manufacturing organizations, may include noncancellable fees. Under such agreements, the exact amounts owed by us in the event of termination will be based on the timing of the termination and the exact terms of the agreement. As of September 30, 2026, we have committed up to approximately $4.6 million under these agreements which are expected to be paid through 2028.

Previous wording

Refer to Note 2 in the accompanying notes to our unaudited interim condensed consolidated financial statements appearing elsewhere in this Quarterly Report on Form 10-Q for a discussion of recent accounting pronouncements. In the six months ended June 30, 2026, there were no newly applicable recently issued accounting pronouncements.

Current wording

Refer to Note 2 in the accompanying notes to our unaudited interim condensed consolidated financial statements appearing elsewhere in this Quarterly Report on Form 10-Q for a discussion of recent accounting pronouncements. In the nine months ended September 30, 2026, there were no newly applicable recently issued accounting pronouncements.