Compass Therapeutics Stock Slides After Mixed Trial Results in Biliary Cancer

Compass Therapeutics saw its stock plunge over 60% after reporting mixed outcomes from its Phase II/III COMPANION-002 trial evaluating tovecimig for biliary tract cancer (BTC).

The study assessed tovecimig, a bispecific antibody, in combination with paclitaxel as a second-line treatment for advanced BTC. While the combination significantly improved progression-free survival (PFS) to 4.7 months versus 2.6 months for paclitaxel alone, it failed to achieve a statistically significant improvement in overall survival (OS). Median OS was 8.9 months in the combination arm compared to 9.4 months in the control group, influenced in part by high crossover rates.

Despite the setback, the therapy demonstrated a manageable safety profile, with hypertension and fatigue among the most common adverse events. Compass plans to engage with the U.S. Food and Drug Administration ahead of a potential Biologics License Application submission.

Following the announcement, the company’s Nasdaq-listed shares dropped sharply, reflecting investor concerns over the missed survival endpoint.

04-05-2026