By Katherine Hamilton
Compass Therapeutics said its cancer treatment improved progression-free survival in a recent trial, but didn't meet its secondary endpoint in overall survival.
Shares fell 23% to $3.85 in premarket trading Monday. Through Friday's close, the stock was down 6% this year.
Compass' trial was studying tovecimig plus paclitaxel as a treatment of biliary tract cancer, which affects the bile ducts or gallbladder.
Tovecimig showed a clinically meaningful and statistically significant improvement in progression-free survival. It reduced the risk of disease progression by 56%.
It didn't meet the overall survival endpoint, however, due to high crossover from the control arm. About 54% of patients crossed over from the control group to receive the treatment that was being studied in the trial.
Because of the high crossover rate, the data from the trial are uninterpretable, Compass said.
Write to Katherine Hamilton at katherine.hamilton@wsj.com
(END) Dow Jones Newswires
April 27, 2026 08:08 ET (12:08 GMT)
Copyright (c) 2026 Dow Jones & Company, Inc.