Biogen Buys Apellis for $5.6 Billion to Expand Kidney Drugs

Biogen Inc. has agreed to acquire Apellis Pharmaceuticals Inc. 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, more than double its closing price on Monday, Biogen said in a statement, confirming a Bloomberg News report. Apellis’ stock had declined 32% so far this year through Monday’s close.