Seralutinib (GB002) - (TORREY/PROSERA)

Mid-June 2026: Gossamer Bio (NASDAQ: GOSS) said it held a pre-NDA Type B meeting with FDA for seralutinib (GB002), an inhaled PDGFR/CSF1R/c-KIT inhibitor for pulmonary arterial hypertension (PAH), and later received meeting minutes. Gossamer said FDA viewed the statistical significance and treatment effect seen in Phase 3 PROSERA as review issues rather than filing issues. The company plans to submit an NDA in September 2026, supported by PROSERA plus confirmatory evidence from Phase 2 TORREY and supportive analyses; if the NDA is accepted, a potential FDA decision could come in Q3 2027.

Seralutinib rights: Gossamer and Chiesi terminated their collaboration and license agreement, with Gossamer reacquiring worldwide development and commercial rights before the planned NDA submission. Chiesi will make a one-time $5 million payment; Gossamer made no upfront cash payment. Chiesi will instead receive capped royalties on worldwide net sales and certain regulatory and commercial milestone payments.

Capital structure: At a July 14, 2026 special meeting, stockholders approved proposals tied to a convertible note exchange and authorized a reverse stock split. The exchange reduced debt principal by about $115.9 million.

Cash: $57.0 million as of June 30, 2026, with runway expected into Q1 2027.