Jan 31 (Reuters) - Biogen Inc said on Wednesday it would terminate a post-approval study of its first Alzheimer's drug, Aduhelm, and discontinue all commercialization for the controversial treatment.

The strategic shift will help the company focus on its second medicine Leqembi, which is led by Japanese partner Eisai , and develop newer treatments for the mind-wasting disease, Biogen said.

Aduhelm, once expected to be the company's next big blockbuster treatment, was riddled with controversy over its approval without clear evidence of patient benefit, and the U.S. Medicare's decision to severely limit access cast serious doubt on its sales potential. (Reporting by Leroy Leo in Bengaluru; Editing by Maju Samuel)