Biogen has agreed to acquire Apellis Pharmaceuticals for approximately $5.6 billion in cash, the companies announced on 31 March, in a move that extends Biogen's existing rare-disease franchise into immunology and kidney disorders.
Biogen was already developing a treatment targeting several kidney conditions, making Apellis a strategically complementary rather than diversifying acquisition. The deal carries a large premium to Apellis's pre-announcement valuation, according to reporting by MarketWatch, though precise per-share terms were not disclosed in available sources.
The transaction reinforces a broader trend among mid-to-large pharmaceutical companies of using acquisitions to replenish pipelines in high-value rare and orphan disease categories, where pricing power and regulatory exclusivity periods are more durable than in primary-care therapeutics.
