Repare Therapeutics (RPTX) shares fell 37% in after-hours trading Thursday as results from a phase 1 trial of cancer drugs disappointed investors.

The combination of lunresertib and camonsertib achieved a 25.9% objective response rate in endometrial cancer and 37.5% in platinum-resistant ovarian cancer in the trial, the company said late Thursday in a statement. The study included heavily pretreated patients.

About half of the patients with gynecologic cancers maintained progression-free survival at 24 weeks, the company said. That compared favorably to the current stand of care, Repare said.

The trial enrolled 51 evaluable patients in the gynecologic cancer expansion cohort, and the therapy demonstrated a favorable and differentiated tolerability profile compared with current and emerging therapies, the company said.

Repare plans to begin a phase 3 registrational trial for endometrial cancer in H2 2025.

Price: 2.52, Change: -1.45, Percent Change: -36.52