Gossamer Submits First Seralutinib NDA for PAH

The Tip Desk · November 12, 2026 · 3 min read

The company booked $38.4 million of collaborator revenue in the third quarter as it closed the Chiesi deal and raised $25 million at an initial private-placement closing.

Gossamer Bio, Inc. (GOSS), a clinical-stage biopharmaceutical company developing seralutinib for pulmonary arterial hypertension, submitted its first New Drug Application to the U.S. Food and Drug Administration in September 2026 for seralutinib in PAH, the same month it had said it intended to file after Pre-NDA Type B meeting minutes.

The NDA is supported by the Phase 3 PROSERA study as one adequate and well-controlled investigation, with confirmatory evidence from the Phase 2 TORREY study and additional supportive analyses. The FDA will determine whether to accept the application for filing after its initial review. Seralutinib remains investigational and has not been approved by any regulatory authority. Chairman, co-founder and chief executive Faheem Hasnain said the company remains focused on supporting the FDA’s review and preparing for a potential commercial launch of seralutinib in 2027.

In the three months ended September 30, 2026, revenue from contracts with collaborators was $38.4 million, up $25.1 million from $13.3 million a year earlier. The company said the increase is primarily attributable to revenue recognized upon termination of the Chiesi collaboration in July 2026, when Gossamer reacquired worldwide development and commercial rights to seralutinib.

That July agreement ended the prior collaboration, with a one-time $5 million payment from Chiesi and no upfront cash from Gossamer. Chiesi remains entitled to a capped royalty and certain regulatory and commercial milestone payments.

Research and development expenses fell to $18.8 million from $45.5 million a year earlier, which the company said was primarily driven by a $15.7 million decrease in seralutinib clinical-trial costs. General and administrative expenses were $9.6 million. The company had $7.2 million of income from operations, versus an operating loss of $49.1 million a year earlier.

Net loss was $48.1 million, or $7.36 a share, compared with a net loss of $48.2 million, or $16.92 a share, a year earlier. Other expense included a $56.5 million remeasurement of warrant liability, producing total other expense of $55.3 million versus $0.9 million of other income a year earlier.

Cash, cash equivalents and marketable securities totaled $51.2 million as of September 30, 2026, down from $57.0 million as of June 30, 2026. Working capital was a deficit of $39.5 million at September 30, versus positive working capital of $104.2 million at December 31, 2025.

In August 2026 the company announced a structured private placement with total potential gross proceeds of up to about $250 million, including about $150 million of committed capital across the initial and second closings. The initial closing provided about $25 million of gross proceeds. The second closing provides for up to about $125 million of additional gross proceeds upon FDA acceptance of the seralutinib NDA in PAH, subject to the milestone occurring in 2026 and other customary closing conditions. Warrants related to FDA approval could provide up to about $100 million of additional gross proceeds, contingent upon FDA approval and cash exercise. Hasnain said FDA acceptance of the application in 2026 would, subject to other customary closing conditions, unlock up to approximately $125 million in additional committed capital to support priorities including preparations for a potential launch.

Gossamer completed a 1-for-80 reverse stock split in September 2026, with split-adjusted trading under the existing Nasdaq symbol GOSS, to regain compliance with the Nasdaq minimum bid-price requirement after stockholders authorized the split in July.