Biogen has agreed to acquire Apellis Pharmaceuticals for approximately $5.6bn.
The deal includes two commercialised, differentiated immunology and rare disease medicines, Empaveli (pegcetacoplan) and Syfovre (pegcetacoplan injection) that will add immediate sales revenue to Biogen, increasing the company’s short and long-term revenue growth profile.
In 2025, the two medicines reached a combined net sales of $689m, a figure that is expected to increase over the next two years.
Empaveli has been approved by the US FDA to treat rare immune-mediated kidney diseases and PNH. Syfovre is FDA-approved for geographic atrophy secondary to age related macular degeneration, an immune-mediated retinal disease.
Apellis has established US sales infrastructure and capabilities, which Biogen believes will accelerate its commercial readiness for felzartamab, a treatment for three kidney diseases currently in phase 3 trials.
Cedric Francois, co-founder and CEO of Apellis, said: “With Biogen’s extensive experience with immunology and rare disease, we believe this transaction will accelerate our impact and enable us to reach more patients.”
The acquisition is expected to close in the second quarter of 2026.
Christopher Viehbacher, Biogen’s President and CEO, said: “The addition of Apellis expands our growth portfolio in immunology and rare disease with two approved, best-in-class medicines that complement our existing portfolio and bolsters our near-and long-term growth potential,”
“We believe our combined capabilities and experience will allow us to maximise the potential of Syfovre and Empaveli, while Apellis’ talent, expertise and field capabilities will further strengthen Biogen, deepening the foundation for our growing nephrology franchise with felzartamab and serving many more patients with immune-mediated retinal disease.”