Shares of Biogen (BIIB:US) moved modestly lower on Friday despite the biopharma giant receiving full approval from the U.S. Food and Drug Administration (FDA) for the Alzheimer’s drug “Leqembi,” which is developed together with Japanese pharma titan Eisai (ESALY:US).

Still, testing requirements and side effect warnings that may limit its use were flagged as negative by biopharma analysts while the full approval was mostly priced in the BIIB stock.

“Today marks a breakthrough in the treatment of Alzheimer’s disease, and we are proud to be at the forefront of ushering in a new era of advances for a disease that was previously considered untreatable,” said Christopher A. Viehbacher, President and Chief Executive Officer of Biogen. 

"Our focus is now on the path forward, working alongside Eisai with the goal of making LEQEMBI accessible to eligible patients as soon as possible.”

This way, Leqembi has become the first and only approved therapy that has proved it can reduce the rate of disease progression while also slowing cognitive and functional decline in adults with this type of disease.

On June 9, the FDA’s Peripheral and Central Nervous System Drugs Advisory Committee (PCNS) voted unanimously to confirm the clinical benefit of Leqembi. In the vast majority of cases, the FDA follows the recommendation from its advisory committees.

Congress members were mostly selling BIIB shares this year. Representatives Ro Khanna, Shri Thanedar, and Daniel Goldman were all selling stock, including Thanedar’s $15,000 - $50,000 sale completed on January 23, when the stock closed at $291.93.

Biogen shares trade about 1.2% lower on Friday, hovering around the $281.50 mark.