Gossamer Bio's stock crashes after Phase 3 trial failure for seralutinib

Gossamer Bio is facing growing uncertainty after its key drug candidate, seralutinib, failed a critical Phase 3 trial. The setback has sent the company's stock plummeting, wiping out much of its market value. Investors and analysts now question whether the drug can still secure regulatory approval.

Earlier this year, seralutinib showed mixed results in the Phase 3 PROSERA study for pulmonary arterial hypertension (PAH). While the trial narrowly missed its primary goal—a statistically significant improvement in six-minute walk distance (6MWD) at 24 weeks—it did show benefits in certain patient groups. Medium- and high-risk participants, including those with connective tissue disease-related PAH, experienced stronger gains, with improvements of up to 37 metres in some cases. Secondary endpoints were also met, offering some hope for the drug's potential.

The trial's failure triggered a sharp sell-off in Gossamer Bio's shares, which have dropped by roughly 86% since January. The stock now trades at around $0.42, pushing the company's market value below $100 million. Major firms like Barclays and Wedbush had already cut their forecasts in late February, deepening the decline.

Analysts remain split on the company's future. Cantor Fitzgerald recently downgraded its rating from 'Overweight' to 'Neutral', while others still recommend buying, with price targets ranging from $0.30 to $15.00. Gossamer Bio has scheduled a 'Type C' meeting with the U.S. Food and Drug Administration (FDA) in June to explore possible paths forward. A decision on whether approval remains viable is expected by July.

The company's next quarterly earnings report is due on May 12, which may provide further clarity on its financial position and strategy.

The failure of seralutinib's Phase 3 trial has left Gossamer Bio in a precarious position. With its stock price near historic lows and regulatory approval in doubt, the company now awaits the FDA's feedback. The outcome of the June meeting will determine whether the drug's development can continue or if the programme faces termination.