Eisai Co. on Friday said it still plans to seek an accelerated U.S. approval pathway for its experimental Alzheimer's drug even after the Medicare health plan decided to severely limit coverage of medicines approved in that manner.

On Thursday, after a monthslong review and a pressure campaign from patient advocacy groups, the Centers for Medicare and Medicaid Services (CMS) said it would only pay for Biogen Inc.'s Aduhelm, and other drugs that work in a similar fashion, for patients enrolled in valid clinical studies, unless they have demonstrated clear evidence of patient benefit.

Medicare covers nearly 64 million Americans age 65 and older, so the coverage decision could affect 85% of people who might otherwise use the medications for the age-related condition.