Business Description

Overview We are a clinical-stage biopharmaceutical company focused on the development and commercialization of seralutinib for the treatment of pulmonary hypertension, or PH, including pulmonary arterial hypertension, or PAH, and PH 3 Table of Contents associated with interstitial lung disease, or PH-ILD. Our goal is to be an industry leader in, and to enhance the lives of patients living with, PH. To accomplish this goal, 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. We intend to maintain a scientifically rigorous and inclusive corporate culture where employees strive to bring improved therapeutic options to patients. Our Team Our founders and management team have held senior positions at leading biopharmaceutical companies and possess substantial experience and expertise across the spectrum of drug development and commercialization. Faheem Hasnain is our Co-Founder and has served as our Chief Executive Officer since November 2020 and as our Chairman since our inception. Mr. Hasnain also served as our Chief Executive Officer from our inception through July 2018 and our Executive Chairman from July 2018 through June 2019. Prior to co-founding Gossamer Bio, Mr. Hasnain served as President, CEO and as a Director of Receptos, Inc. from November 2010 to August 2015. Receptos was a public company formed in 2009 focused on developing treatments in immunology and metabolic disorders and was purchased by Celgene Corporation in August 2015. Previously, Mr. Hasnain was the President and Chief Executive Officer and a director of Facet Biotech Corporation, a biology-driven antibody company with a focus in multiple sclerosis and oncology. He held that position from December 2008 until the company's acquisition by Abbott Laboratories in April 2010. Bryan Giraudo, our Chief Financial Officer and Chief Operating Officer, has extensive biotechnology and medical technology finance experience, having previously served as Senior Managing Director at Leerink Partners and Managing Director at Merrill Lynch, Pierce, Fenner & Smith Incorporated. Bob Smith, our Chief Commercial Officer, has over 30 years of experience in pharmaceuticals, with a strong focus on PAH and rare disease. Prior to Gossamer, Mr. Smith was the National Sales Lead in charge of preparing for the commercial launch of sotatercept for the treatment of PAH in the US at Merck & Co., or Merck. Previously until 2018, Mr. Smith was the Senior Vice President of Sales and an Executive Leadership Team member at Actelion Pharmaceuticals US, Inc., where he spearheaded two successful PAH drug launches, Opsumit (macitentan) and Uptravi (selexipag). Christian Waage, our Executive Vice President, Technical Operations & Administration, has meaningful management biotechnology experience, having previously held various positions at Receptos, most recently as Managing Director after its acquisition by Celgene, and at Ardea Biosciences, Inc. as Vice President, General Counsel. Caryn Peterson, our Executive Vice President, Regulatory Affairs, has considerable experience and regulatory expertise as a Managing Director of Development & Strategic Consulting Associates, as well as management positions leading regulatory affairs at Syndax Pharmaceuticals and FeRx Incorporated. Our Strategy Our near-term strategy is to focus our resources on advancing seralutinib for the treatment of PAH and to pursue regulatory alignment and potential approval as efficiently as possible. Based on the totality of data from the Phase 3 PROSERA Study and the Phase 2 TORREY Study, including general consistency across endpoints and within higher risk subgroups, we believe seralutinib demonstrates a risk benefit profile that supports continued regulatory dialogue. Following our February 2026 announcement of topline results from PROSERA, we are prioritizing (i) completing in-depth analyses of the PROSERA dataset, (ii) engaging with the U.S. Food and Drug Administration, or FDA, to obtain feedback regarding potential regulatory paths forward, and (iii) evaluating our strategic options and resource allocation as a company, in addition to strengthening our capital structure. The key elements of our near-term strategy include: • Obtain FDA feedback and seek to define a regulatory path forward in PAH.…