Biogen to Buy Apellis for $5.6 Billion to Boost Kidney Franchise

Biogen has agreed to acquire Apellis Pharmaceuticals for $5.6 billion, expanding its treatments in immunology and rare diseases in one of the company’s largest-ever acquisitions.

The Cambridge, Massachusetts-based biotech company will pay $41 a share for Apellis, or more than double the company’s closing price on Monday. Apellis’ stock has declined 32% so far this year.

Apellis shares soared 137.6% in pre-market trading. Biogen shares were down about 1%.

Biogen will gain two approved drugs in the deal. Apellis’ best-selling medicine is Syfovre, which treats an immune disorder that’s a leading cause of blindness. It generated $587 million in revenue last year. The other, Empaveli, treats both a blood disorder and rare kidney diseases, the latter of which has become an area of focus for Biogen. Last year, Empaveli generated more than $100 million in sales.

Biogen Chief Executive Officer Chris Viehbacher has been trying to find new sources of growth as the company’s aging multiple sclerosis franchise declines and its Alzheimer’s treatment gets off to a slow start.