- Trial Phase
- Phase 3 (completed; missed primary endpoint)
- Time to Market
- Target NDA submission September 2026; potential FDA approval Q3 2027 if accepted — but highly uncertain given the failed Phase 3.
- Why 4/10
- The next hard catalyst is the NDA submission for seralutinib in PAH (targeted September 2026), contingent on the pre-NDA Type B meeting outcome from mid-June 2026. However, the defining binary event — the Phase 3 PROSERA readout (Feb 23, 2026) — has already passed and was a failure, and the drug is the company's only asset, so upside is capped by low FDA-approval odds for a drug that missed its primary endpoint.
Watch for the public disclosure of the pre-NDA meeting outcome (mid-June 2026 meeting). If the FDA pushes back on filing, the stock could fall further. If the FDA allows the NDA submission to proceed, a September filing announcement could trigger a short-term bounce. Either way, this is a distressed penny stock — position sizing should account for potential total loss.
Price Chart
Executive Summary
Seralutinib is Gossamer Bio's only pipeline asset — an inhaled kinase inhibitor for pulmonary arterial hypertension (PAH) and pulmonary hypertension associated with interstitial lung disease (PH-ILD). The pivotal Phase 3 PROSERA study announced February 23, 2026 narrowly missed its primary endpoint (13.3m improvement in 6-minute walk distance, p=0.032 vs pre-specified α of 0.025), triggering an ~80% single-day stock crash and a wave of analyst downgrades. Despite the miss, management completed a pre-NDA meeting with the FDA in mid-June 2026 and is targeting an NDA submission in September 2026, with potential approval in Q3 2027 if accepted. The company has restructured $181M in convertible debt (highly dilutive), cut ~50% of staff, and paused its second Phase 3 trial (SERANATA for PH-ILD). With the stock trading around $0.16, a market cap of ~$80M, and class-action lawsuits pending, seralutinib represents a deeply distressed, high-risk speculative play with a low-probability regulatory path forward.
How It Works
Seralutinib is an inhaled small-molecule drug that blocks three cell-surface receptors (PDGFR, CSF1R, and c-KIT) involved in the abnormal cell growth and inflammation that causes blood vessels in the lungs to narrow in pulmonary hypertension. It is designed as a dry powder inhaler to deliver the drug directly to the lungs while minimizing side effects elsewhere in the body.
Trial Status
Phase 3 PROSERA study in PAH completed Feb 2026 — missed primary endpoint (6-minute walk distance, p=0.032 vs α=0.025). Company still pursuing NDA. Phase 2 TORREY study had met its primary endpoint (PVR reduction) and was published in Lancet Respiratory Medicine. Phase 3 SERANATA trial for PH-ILD paused enrollment pending evaluation of PROSERA data.
The Two-Sided Case
Upcoming Catalysts
- Disclosure of FDA pre-NDA Type B meeting outcome (mid-June 2026 meeting — awaiting public readout)
- NDA submission for seralutinib in PAH (targeted September 2026)
- Potential FDA acceptance/rejection of NDA filing (post-submission)
- Special stockholder meeting July 14, 2026, to vote on debt-restructuring proposals
- Class action lawsuit developments and any settlement news
Source Filing
The SecBot filing or press-release report that triggered this drug report:
Gossamer Bio, Inc. 8-K GOSS ·Originating report