Dec 21 (Reuters) - Biogen Inc said on Thursday one of its drug to treat Alzheimer's disease failed to meet the main goal of a mid-stage trial, sending the drugmaker's shares down 4.3 percent in premarket trading.
The company said an independent data monitoring board concluded that its drug, BAN2401, did not show success in patients with Alzheimer's disease during an interim analysis.
However, Biogen said the 18-month trial will continue for further analysis, the data from which is expected in the second half of next year.
"The fact that BAN2401 study did not stop for futility suggests some benefits are being observed," RBC Capital Markets analyst Brian Abrahams said.
The U.S. drugmaker is developing BAN2401 and another Alzheimer's drug, aducanumab, in collaboration with Japan's Eisai Co Ltd.
Mizuho's analyst Salim Syed said the interim data announced on Thursday should be viewed separately from the upcoming late-stage data testing Biogen's aducanumab.
"BAN2401 and aducanumab are not the same antibody," he said.
Shares of Biogen, which amended its agreement with Eisai in October by eliminating milestone payments for both its Alzheimer's drugs, were down 4.3 percent at $319. (Reporting by Divya Grover in Benagluru; Editing by Anil D'Silva)