Gossamer Bio's PAH drug fails phase 3 trial, sending stock into freefall

Gossamer Bio faced a major setback in February 2026 when its phase 3 PROSERA study failed to meet its primary goal. The disappointing results for seralutinib, a potential treatment for pulmonary arterial hypertension, triggered a sharp reaction from investors and analysts alike. Several firms have since slashed their price targets for the company's stock.

The failed trial led to swift downgrades in early March. Barclays Capital cut its target price from $12 to $3 while keeping an 'Outperform' rating. Other analysts followed, reducing their targets to around $1. Cantor Fitzgerald went further, lowering its rating from 'overweight' to 'neutral'.

The uncertainty now centres on the drug's regulatory future. Gossamer Bio has requested a Type C meeting with the US Food and Drug Administration, scheduled for June. A clearer path for seralutinib is expected in July, after the meeting takes place. Despite the setback, some analysts remain cautiously optimistic. Olivia Brayer Saunders highlighted compelling data and a strong signal for seralutinib's potential. However, the downgrades reflect concerns over the drug's approval prospects rather than its efficacy alone.

Gossamer Bio's next steps depend on the FDA's feedback in July. The company's stock has already taken a hit as analysts adjust expectations. Any further decisions on seralutinib's development will hinge on the outcome of the upcoming regulatory discussions.