U.S. FDA approves Biogen Alzheimer's drug

By Deena Beasley

(Reuters) -U.S. regulators on Monday approved Biogen Inc's aducanumab as the first treatment to address an underlying cause of Alzheimer's disease despite controversy over mixed clinical trial results for the drug.

Aducanumab is one of a long list of drugs that have aimed to remove sticky deposits of a protein called amyloid beta from the brains of patients in earlier stages of Alzheimer's in order to stave off its ravages, which include memory loss and the ability to care for oneself.

Biogen's drug had been hailed by patient advocates and some neurologists eager to have an effective option for patients with the lethal disease, but other doctors said clinical trial results were inconsistent and more proof was needed.

Aducanumab was studied in patients with early disease who test positive for a component of amyloid brain plaques. Some trial patients experienced potentially dangerous brain swelling.

Biogen has estimated that around 1.5 million Americans would be eligible for treatment with aducanumab, which is given by monthly infusion, raising concerns about costs to the healthcare system.

(Reporting by Deena Beasley in Los Angeles; Additional reporting by Ankur Banerjee in Bengaluru; Editing by Bill Berkrot, Kirsten Donovan and Shounak Dasgupta)