Seralutinib (GB002) - (TORREY/PROSERA)

May 18, 2026: Gossamer Bio, Inc. (NASDAQ: GOSS) reported Q1 2026 results and provided a regulatory and data update for seralutinib (GB002), an inhaled PDGFR/CSF1R/c‑KIT inhibitor being co-developed with Chiesi for pulmonary arterial hypertension (PAH) (and PH-ILD).

Regulatory catalyst: FDA confirmed an in-person Pre-NDA Type B meeting scheduled for mid-June 2026 (the company pursued Type B instead of a previously anticipated Type C) to discuss the totality of evidence from the Phase 3 PROSERA dataset. Subject to that meeting, Gossamer expects to submit an NDA for seralutinib in PAH in September 2026. If accepted for filing, the company states seralutinib could be eligible for FDA approval in Q3 2027.

Clinical/imaging catalyst: Topline results from the PROSERA CT functional respiratory imaging (FRI) exploratory substudy (n=162) showed nominal, unadjusted statistically significant treatment effects vs placebo across multiple compartments, including arterial (e.g., reduced proportion of blood volume in larger arterial vessels; p=0.0200), venous (increased total venous blood volume p=0.0155; small venous vessel volume p=0.0341), and fibrosis-like parenchymal measures (reduced absolute/normalized fibrosis-like tissue p=0.0260/0.0250). Imaging changes were reported as correlated with clinical outcomes (hemodynamics, NT‑proBNP, 6MWD, REVEAL Lite 2).

Financing/capital structure: The company commenced an exchange offer for $200M 5.00% convertible notes due 2027, targeting reduced convertible debt to $72M upon full participation, alongside a consent solicitation; ~75.2% of holders signed a support agreement.

Financials: Cash/cash equivalents/marketable securities were $99.2M at March 31, 2026; net loss was $46.7M. Management guided cash runway into Q1 2027.