U.S. approval of Biogen Alzheimer’s drug sends shares soaring, hailed as ‘big day” for patients

U.S. regulators on Monday approved Biogen Inc’s (BIIB.O) aducanumab as the first treatment to attack a likely cause of Alzheimer’s disease despite controversy over whether the clinical evidence proves the drug works, sending its shares soaring.

Biogen said it has priced the drug, to be sold as Aduhelm, at $56,000 per year. After jumping more than 50%, Biogen shares closed up 38.3% at $395.85 – their highest closing level in over six years. U.S. traded shares of Japanese partner Eisai Co (4523.T) rose 56% to $116.03. Aducanumab works by removing 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 inability to care for oneself.

“This is good news for patients with Alzheimer’s disease. We’ve not had a disease modifying therapy approved ever,” said Dr. Ronald Petersen, an Alzheimer’s disease expert at the Mayo Clinic. However, he cautioned, “This is not a cure. It’s hoped that this will slow the progression of the disease.”