Biogen acquires Apellis Pharmaceuticals

Biogen has completed its acquisition of Apellis Pharmaceuticals for $5.6 billion, a strategic move intended to diversify its portfolio and strengthen its foothold in the rare disease and nephrology markets. This acquisition marks a pivot from Biogen's traditional focus on neuroscience as the company faces revenue pressures from its older multiple sclerosis drugs.

Biogen acquired Apellis through a tender offer and merger transaction, valuing Apellis at $41 per share in cash. The deal also includes contingent value rights linked to future sales milestones for Apellis' notable treatment, SYFOVRE. Following the acquisition, Apellis' shares are no longer traded on Nasdaq. This transaction boosts Biogen's lineup with Apellis' two commercial complement-targeting therapies: SYFOVRE, a landmark treatment for geographic atrophy, and EMPAVELI, used for conditions like paroxysmal nocturnal hemoglobinuria and C3 glomerulopathy. The two therapies combined generated $689 million in net revenue in 2025.

This acquisition indicates Biogen's strategic expansion into complement biology, a growing therapeutic area with substantial commercial potential due to high unmet needs in rare diseases. Biogen anticipates that the addition of Apellis' assets will support revenue and earnings growth, with the deal becoming accretive to non-GAAP earnings per share starting in 2027. This move also aligns with Biogen's pipeline advancements, including the upcoming launch of felzartamab, aimed at nephrology markets.

In the context of the broader pharmaceutical landscape, Biogen's acquisition underscores a trend among major pharmaceutical firms pursuing external innovation in specialty therapeutics. The interest in complement-targeting therapies reflects the industry's broader focus on diseases with significant unmet needs and the opportunity for specialized, value-based pricing.

Looking ahead, Biogen plans to provide updated financial guidance in alignment with its second-quarter earnings report in July. Additionally, a Phase 3 readout for felzartamab is anticipated in the first half of 2027, marking a key milestone in Biogen's evolving strategy in nephrology and rare diseases.