Gossamer Bio, Inc.

Previous wording

This quarterly report on Form 10-Q contains forward-looking statements within the meaning of Section 21E of the Securities Exchange Act of 1934, as amended, or the Exchange Act, and Section 27A of the Securities Act of 1933, as amended, or the Securities Act. All statements other than statements of historical facts contained in this quarterly report, including statements regarding our future results of operations and financial position, including performance under the Chiesi Collaboration Agreement and the potential future issuance of our common stock to Chiesi pursuant to the Equity Option, business strategies and plans, research and development plans, the anticipated timing, costs, design and conduct of our ongoing and planned preclinical studies and planned clinical trials for seralutinib, the timing and likelihood of regulatory filings and approvals for seralutinib, timing and likelihood of success, plans and objectives of management for future operations, the potential of U.S. trade policy, including tariffs, and future results of seralutinib, are forward-looking statements. These statements involve known and unknown risks, uncertainties and other important factors that may cause our actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by the forward-looking statements.

Current wording

This quarterly report on Form 10-Q contains forward-looking statements within the meaning of Section 21E of the Securities Exchange Act of 1934, as amended, or the Exchange Act, and Section 27A of the Securities Act of 1933, as amended, or the Securities Act. All statements other than statements of historical facts contained in this quarterly report, including statements regarding our future results of operations and financial position, including performance under the Chiesi Collaboration Agreement and the potential future issuance of our common stock to Chiesi pursuant to the Equity Option, business strategies and plans, research and development plans, the anticipated timing, costs, design and conduct of our ongoing and planned preclinical studies and planned clinical trials for seralutinib, the timing and likelihood of regulatory filings and approvals for seralutinib, timing and likelihood of success, plans and objectives of management for future operations, the potential impact of U.S. trade policy, including tariffs, and future results of seralutinib, are forward-looking statements. These statements involve known and unknown risks, uncertainties and other important factors that may cause our actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by the forward-looking statements.

Previous wording

We are a late-stage, clinical biopharmaceutical company focused on the development and commercialization of seralutinib for the treatment of PH, including PAH and PH-ILD. Our goal is to be an industry leader in, and to enhance the lives of patients living with PH. In May 2024, we entered into the Chiesi Collaboration Agreement focused on the development and commercialization of seralutinib. In December 2022, we announced positive topline results from the Phase 2 TORREY Study in PAH patients. In the fourth quarter of 2023, we initiated the registrational Phase 3 PROSERA Study in PAH. We expect to report topline data from the PROSERA study in February 2026. In addition to PAH, we believe that seralutinib holds potential as a therapeutic for the treatment of PH-ILD. We expect to activate the first clinical sites for the global registrational Phase 3 SERANATA Study for the treatment of PH-ILD in the fourth quarter of 2025. We have assembled a deeply experienced and highly skilled group of industry veterans, scientists, clinicians and key opinion leaders from leading biotechnology and pharmaceutical companies, as well as leading academic centers from around the world. Our employees are a team of highly dedicated, passionate individuals who pride themselves on a culture of respect, humility, transparency, inclusion, dedication, collaboration and fun. Our ultimate goal is to enhance and extend the lives of patients.

Current wording

We are a late-stage, clinical biopharmaceutical company focused on the development and commercialization of seralutinib for the treatment of PH, including PAH and PH-ILD. Our goal is to be an industry leader in, and to enhance the lives of patients living with PH. In May 2024, we entered into the Chiesi Collaboration Agreement focused on the development and commercialization of seralutinib. In December 2022, we announced positive topline results from the Phase 2 TORREY Study in PAH patients. In the fourth quarter of 2023, we initiated the registrational Phase 3 PROSERA Study in PAH. In June 2025, we announced the completion of enrollment for the ongoing, global registrational Phase 3 PROSERA Study evaluating seralutinib in Functional Class II and III PAH patients. We expect to report topline data from the PROSERA study in February 2026. In addition to PAH, we believe that seralutinib holds potential as a therapeutic for the treatment of PH-ILD. We expect to activate the first clinical sites for the global registrational Phase 3 SERANATA Study for the treatment of PH-ILD in the fourth quarter of 2025. We have assembled a deeply experienced and highly skilled group of industry veterans, scientists, clinicians and key opinion leaders from leading biotechnology and pharmaceutical companies, as well as leading academic centers from around the world. Our employees are a team of highly dedicated, passionate individuals who pride themselves on a culture of respect, humility, transparency, inclusion, dedication, collaboration and fun. Our ultimate goal is to enhance and extend the lives of patients.

Previous wording

We were incorporated in October 2015 and commenced operations in 2017. To date, we have focused primarily on organizing and staffing our company, business planning, raising capital, identifying, acquiring and in-licensing our product candidates and conducting preclinical studies and clinical trials. We have funded our operations primarily through equity and debt financings and the collaboration agreement. As of March 31, 2025, we had $257.9 million in cash, cash equivalents and marketable securities.

Current wording

We were incorporated in October 2015 and commenced operations in 2017. To date, we have focused primarily on organizing and staffing our company, business planning, raising capital, identifying, acquiring and in-licensing our product candidates and conducting preclinical studies and clinical trials. We have funded our operations primarily through equity and debt financings and the collaboration agreement. As of June 30, 2025, we had $212.9 million in cash, cash equivalents and marketable securities.

Previous wording

We have incurred significant operating losses since our inception and expect to continue to incur significant operating losses for the foreseeable future. For the three months ended March 31, 2025 and 2024, our net loss was $36.6 million and $41.9 million, respectively. As of March 31, 2025, we had an accumulated deficit of $1,305.2 million. We expect to incur expenses and operating losses for the foreseeable future as we continue our development of and seek regulatory approvals for seralutinib, including the conduct of ongoing and planned clinical trials and other research and development activities; and as we hire additional personnel, protect our intellectual property and incur additional costs associated with being a public company. In addition, as seralutinib progresses through development and toward commercialization, we will need to make milestone payments to Pulmokine from whom we have in-licensed seralutinib. Our net losses may fluctuate significantly from quarter-to-quarter and year-to-year, depending in particular on the timing of our clinical trials and preclinical studies and our expenditures on other research and development activities.

Current wording

We have incurred significant operating losses since our inception and expect to continue to incur significant operating losses for the foreseeable future. For the three months ended June 30, 2025 and 2024, our net loss was $38.3 million and net income was $49.2 million, respectively. For the six months ended June 30, 2025 and 2024, our net loss was $74.9 million and net income was $7.3 million, respectively. As of June 30, 2025, we had an accumulated deficit of $1,343.5 million. We expect to incur expenses and operating losses for the foreseeable future as we continue our development of and seek regulatory approvals for seralutinib, including the conduct of ongoing and planned clinical trials and other research and development activities; and as we hire additional personnel, protect our intellectual property and incur additional costs associated with being a public company. In addition, as seralutinib progresses through development and toward commercialization, we will need to make milestone payments to Pulmokine from whom we have in-licensed seralutinib. Our net losses may fluctuate significantly from quarter-to-quarter and year-to-year, depending in particular on the timing of our clinical trials and preclinical studies and our expenditures on other research and development activities.

Previous wording

Our direct research and development expenses consist principally of external costs, such as fees paid to CROs, investigative sites and consultants in connection with our clinical trials, preclinical and non-clinical studies, and costs related to manufacturing clinical trial materials. We deploy our personnel and facility related resources across all of our research and development activities. We track external costs and personnel expense on a program-by-program basis and allocate common expenses, such as facility related resources, to each program based on the personnel resources allocated to such program. Stock-based compensation and personnel and common expenses not attributable to a specific program are considered unallocated research and development expenses. We categorize Terminated Programs as any research and development expenses attributable to our clinical stage product candidates that were terminated prior to December 31, 2023.

Current wording

Our direct research and development expenses consist principally of external costs, such as fees paid to CROs, investigative sites and consultants in connection with our clinical trials, preclinical and non-clinical studies, and costs related to manufacturing clinical trial materials. We deploy our personnel and facility related resources across all of our research and development activities. We track external costs and personnel expense on a program-by-program basis and allocate common expenses, such as facility related resources, to each program based on the personnel resources allocated to such program. Stock-based compensation and personnel and common expenses not attributable to a specific program are considered unallocated research and development expenses. We categorize Terminated Programs as any research and development expenses attributable to our clinical stage product candidates that were terminated prior to December 31, 2023 or any research and development expenses that are not directly allocated to seralutinib.

Previous wording

Other income, net consists of (1) interest income on our cash, cash equivalents and marketable securities, (2) investment accretion, (3) interest expense related to our Credit Facility prior to its termination and the 2027 Notes, (4) research and development tax credit and (5) other miscellaneous income (expense).

Current wording

Other income (expense), net consists of (1) interest income on our cash, cash equivalents and marketable securities, (2) investment accretion, (3) interest expense related to our Credit Facility prior to its termination and the 2027 Notes, (4) research and development tax credit and (5) other miscellaneous income (expense).

Previous wording

Our management’s discussion and analysis of our financial condition and results of operations are based on our condensed consolidated financial statements, which have been prepared in accordance with GAAP. The preparation of these financial statements requires us to make judgments and estimates that affect the reported amounts of assets, liabilities, revenue, expenses and the disclosure of contingent assets and liabilities in our condensed consolidated financial statements. We base our estimates on historical experience, known trends and events, and various other factors that are believed to be reasonable under the circumstances. Actual results may differ from these estimates under different assumptions or conditions. On an ongoing basis, we evaluate our judgments and estimates in light of changes in circumstances, facts and experience. During the three months ended March 31, 2025, there have been no significant changes in our critical accounting policies and estimates as discussed in Item 7, “Management’s Discussion and Analysis of Financial Condition and Results of Operations – Critical Accounting Policies and Estimates” in our Annual Report on Form 10-K filed with the SEC on March 13, 2025.

Current wording

Our management’s discussion and analysis of our financial condition and results of operations are based on our condensed consolidated financial statements, which have been prepared in accordance with GAAP. The preparation of these financial statements requires us to make judgments and estimates that affect the reported amounts of assets, liabilities, revenue, expenses and the disclosure of contingent assets and liabilities in our condensed consolidated financial statements. We base our estimates on historical experience, known trends and events, and various other factors that are believed to be reasonable under the circumstances. Actual results may differ from these estimates under different assumptions or conditions. On an ongoing basis, we evaluate our judgments and estimates in light of changes in circumstances, facts and experience. During the six months ended June 30, 2025, there have been no significant changes in our critical accounting policies and estimates as discussed in Item 7, “Management’s Discussion and Analysis of Financial Condition and Results of Operations – Critical Accounting Policies and Estimates” in our Annual Report on Form 10-K filed with the SEC on March 13, 2025.

Previous wording

Results of Operations – Comparison of the Three Months Ended March 31, 2025 and 2024

Current wording

Results of Operations – Comparison of the Three and Six Months Ended June 30, 2025 and 2024

Previous wording

For the three months ended March 31, 2025, our revenue was $9.9 million. Our revenue is generated from our ongoing collaboration with Chiesi and consists of a one-time development cost reimbursement payment for the licenses and ongoing cost-sharing payments for performance of research and development and pre-commercial services.

Current wording

For the three months ended June 30, 2025 and 2024, our revenue was $11.5 million and $95.8 million, respectively. For the six months ended June 30, 2025 and 2024, our revenue was $21.4 million and $95.8 million, respectively. Our revenue is generated from our ongoing collaboration with Chiesi and consists of a one-time development cost reimbursement payment for the licenses and ongoing cost-sharing payments for performance of research and development and pre-commercial services.

Previous wording

Research and development expenses were $38.0 million for the three months ended March 31, 2025, compared to $32.4 million for the three months ended March 31, 2024, for an increase of $5.6 million, which was primarily attributable to an increase of $6.5 million of costs associated with preclinical studies and clinical trials for seralutinib, offset by a decrease of $0.9 million of costs associated with preclinical studies and clinical trials for terminated programs.

Current wording

Research and development expenses were $41.6 million for the three months ended June 30, 2025, compared to $35.1 million for the three months ended June 30, 2024, for an increase of $6.5 million, which was primarily attributable to an increase of $9.0 million of costs associated with preclinical studies and clinical trials for seralutinib, offset by a decrease of $2.5 million of costs associated with preclinical studies and clinical trials for terminated programs.

Previous wording

The following table shows our research and development expenses by program for the three months ended March 31, 2025 and 2024:

Current wording

The following table shows our research and development expenses by program for the three and six months ended June 30, 2025 and 2024:

Previous wording

General and administrative expenses were $8.7 million for the three months ended March 31, 2025, compared to $9.6 million for the three months ended March 31, 2024, for a decrease of $0.9 million, which was primarily attributable to a $1.6 million decrease in stock-based compensation expense, offset by an increase of $0.4 million in compensation expense and an increase of $0.1 million in professional services expense.

Current wording

General and administrative expenses were $17.3 million for the six months ended June 30, 2025, compared to $18.2 million for the six months ended June 30, 2024, for a decrease of $0.9 million, which was primarily attributable to a $2.8 million decrease in stock-based compensation expense, offset by an increase of $2.0 million in commercial expenses.

Previous wording

We have incurred substantial operating losses since our inception and expect to continue to incur significant operating losses for the foreseeable future and may never become profitable. As of March 31, 2025, we had an accumulated deficit of $1,305.2 million.

Current wording

We have incurred substantial operating losses since our inception and expect to continue to incur significant operating losses for the foreseeable future and may never become profitable. As of June 30, 2025, we had an accumulated deficit of $1,343.5 million.

Previous wording

From our inception through March 31, 2025, our operations have been financed primarily by proceeds of $1,393.2 million from the sale of Series A and Series B convertible preferred stock, proceeds from our IPO, proceeds from the 2027 Notes, proceeds from issuance of common stock in May 2020 and July 2022, proceeds from issuance of common stock and accompanying warrants in July 2023 and the Chiesi Collaboration Agreement. In addition, we have received $13.2 million as of March 31, 2025 through reimbursement related to the Chiesi Collaboration Agreement. As of March 31, 2025 we had cash, cash equivalents and marketable securities of $257.9 million. Cash in excess of immediate requirements is invested in accordance with our investment policy, primarily with a view to capital preservation and liquidity.

Current wording

From our inception through June 30, 2025, our operations have been financed primarily by proceeds of $1,393.2 million from the sale of Series A and Series B convertible preferred stock, proceeds from our IPO, proceeds from the 2027 Notes, proceeds from issuance of common stock in May 2020 and July 2022, proceeds from issuance of common stock and accompanying warrants in July 2023 and the Chiesi Collaboration Agreement. In addition, we have received $19.8 million as of June 30, 2025 through reimbursement related to the Chiesi Collaboration Agreement. As of June 30, 2025 we had cash, cash equivalents and marketable securities of $212.9 million. Cash in excess of immediate requirements is invested in accordance with our investment policy, primarily with a view to capital preservation and liquidity.

Previous wording

On May 3, 2024, we entered into the Chiesi Collaboration Agreement. In consideration and as reimbursement for our development costs, Chiesi paid us an up-front, nonrefundable payment of $160.0 million. In addition, we and Chiesi share equally in the costs of ongoing global seralutinib clinical development, with the exception of the PROSERA Phase 3 study, and the costs of commercialization in the U.S. Territory. For the three months ended on March 31, 2025, we received cost-sharing payments from Chiesi in the amount of $5.3 million.

Current wording

On May 3, 2024, we entered into the Chiesi Collaboration Agreement. In consideration and as reimbursement for our development costs, Chiesi paid us an up-front, nonrefundable payment of $160.0 million. In addition, we and Chiesi share equally in the costs of ongoing global seralutinib clinical development, with the exception of the PROSERA Phase 3 study, and the costs of commercialization in the U.S. Territory. For the six months ended on June 30, 2025, we received cost-sharing payments from Chiesi in the amount of $11.9 million.

Previous wording

The following table shows a summary of our cash flows for each of the three months ended March 31, 2025 and 2024, respectively:

Current wording

The following table shows a summary of our cash flows for each of the six months ended June 30, 2025 and 2024, respectively:

Previous wording

During the three months ended March 31, 2024, operating activities used approximately $52.3 million of cash, primarily resulting from a net loss of $41.9 million and changes in accrued expenses of $9.3 million, changes in amortization of premium on marketable securities, net of accretion of premium of $3.0 million and changes in accrued compensation and benefits of $4.6 million, reduced by stock-based compensation expense of $5.8 million.

Current wording

During the six months ended June 30, 2025, operating activities used approximately $86.8 million of cash, primarily resulting from a net loss of $74.9 million, changes in accounts payable of $6.8 million, changes in prepaid expenses and other current assets of $5.4 million and changes in amortization of premium on investments of $4.6 million, reduced by changes in stock-based compensation expense of $5.0 million.

Previous wording

During the three months ended March 31, 2025, operating activities used approximately $39.7 million of cash, primarily resulting from the net loss of $36.6 million and changes in accrued compensation and benefits of $5.8 million, reduced by changes in stock-based compensation expense of $2.4 million.

Current wording

During the six months ended June 30, 2024, operating activities provided approximately $64.0 million of cash, primarily resulting from a net income of $7.3 million and changes in contract liabilities of $66.7 million, reduced by changes in accrued expenses of $6.3 million and changes in amortization of premium on marketable securities, net of accretion of $6.0 million.

Previous wording

During the three months ended March 31, 2025, investing activities provided approximately $22.1 million of cash, primarily resulting from the maturities of marketable securities of $123.1 million, offset by the purchases of marketable securities of $101.0 million.

Current wording

During the six months ended June 30, 2025, investing activities provided approximately $66.2 million of cash, primarily resulting from the maturities of marketable securities of $242.8 million, offset by the purchases of marketable securities of $176.5 million.

Previous wording

During the three months ended March 31, 2024, investing activities provided approximately $61.7 million of cash, primarily resulting from the maturities of marketable securities of $147.8, offset by the purchases of marketable securities of $86.1 million.

Current wording

During the six months ended June 30, 2024, investing activities provided approximately $2.6 million of cash, primarily resulting from the maturities of marketable securities of $282.3 million, offset by the purchases of marketable securities of $279.7 million.

Previous wording

During the three months ended March 31, 2025, financing activities provided $0.5 million of cash, primarily resulting from the proceeds from issuance of common stock pursuant to the ESPP of $0.4 million and the proceeds from the exercise of stock options of $0.1 million.

Current wording

During the six months ended June 30, 2025, financing activities provided $0.6 million of cash, primarily resulting from the proceeds from issuance of common stock pursuant to the ESPP of $0.4 million and the proceeds from the exercise of stock options of $0.2 million.

Previous wording

During the three months ended March 31, 2024, financing activities used $2.6 million of cash, primarily resulting from the principal repayments of long-term debt of $2.9 million, reduced by the proceeds from issuance of common stock pursuant to the ESPP of $0.3 million.

Current wording

During the six months ended June 30, 2024, financing activities used $11.8 million of cash, primarily resulting from the principal repayments of long-term debt of $12.6 million, reduced by the proceeds from the grant of an equity option pursuant to the Chiesi Collaboration Agreement of $0.5 million and the proceeds from issuance of common stock pursuant to the ESPP of $0.3 million.