Biogen Inc has agreed to acquire Apellis Pharmaceuticals in a deal valued at approximately $5.6 billion, the companies announced in a press release. Under the terms of the agreement, Biogen will acquire all outstanding shares of Apellis for $41.00 per share in cash at closing.

The acquisition is expected to enhance Biogen’s near- and long-term revenue growth by adding a pair of commercialized therapies, Syfovre and Empaveli, to its portfolio. Both are formulations of the same molecule, pegcetacoplan, a complement C3 inhibitor developed by Apellis. Syfovre is approved by the US Food and Drug Administration (FDA) for geographic atrophy secondary to age-related macular degeneration. Apellis has completed a clinical trial evaluating a prefilled syringe for Syfovre and plans to submit an application for FDA approval in the first half of 2026. Empaveli is approved for paroxysmal nocturnal hemoglobinuria and certain rare immune-mediated kidney diseases.

Apellis also brings an established US commercial infrastructure, including capabilities in nephrology. Biogen said this infrastructure may support the future launch of felzartamab, which is currently in phase 3 studies across 3 kidney diseases, with the first readout expected in the first half of 2027.

The transaction is expected to close in the second quarter of 2026. The companies said the addition of Apellis would contribute commercial products that generated $689 million in revenue in 2025 and are projected to grow at a mid- to high-teens rate through at least 2028.

Biogen stated that the acquisition aligns with its strategy to expand its growth portfolio and strengthen its position in immunology, rare disease, and retinal therapeutics. RP