Tags: layoffs, strategy

Gossamer Bio Cuts Nearly Half Its Staff After Phase 3 Hypertension Drug Fails

By FieldPulse Editorial · March 17, 2026

Gossamer Bio cuts 48% of staff after Phase 3 PAH drug seralutinib misses primary endpoint. 77 employees laid off; company now exploring strategic options.

Gossamer Bio announced on March 17, 2026 that it would eliminate 77 employees — approximately 48% of its total workforce — after its Phase 3 PROSERA trial of seralutinib in pulmonary arterial hypertension (PAH) missed its primary endpoint.

The trial showed a placebo-adjusted 13.3-meter improvement in six-minute walk distance, falling short of the statistical threshold needed for approval.

The company is now conserving cash and exploring strategic options, including a potential asset sale or partnership.

Gossamer previously raised the Phase 3 readout as a potential near-term catalyst.

The failure adds to a string of late-stage PAH setbacks in the industry.

For reps in the pulmonary hypertension space, the competitive landscape remains concentrated around established players including Johnson & Johnson's macitentan and United Therapeutics' treprostinil portfolio, with fewer pipeline threats expected in the near term.