Biogen Acquires Apellis for $5.6 Billion

Biogen has concluded its acquisition of Apellis Pharmaceuticals for $5.6 billion, marking a strategic expansion into the rare disease and nephrology sectors. This move is intended to diversify Biogen's portfolio as it seeks growth avenues beyond its established neuroscience business. The deal includes a purchase price of $41 per share in cash, along with contingent value rights linked to future sales of Apellis’s SYFOVRE product.

Now a wholly owned subsidiary of Biogen, Apellis brings two commercial therapies to the company: SYFOVRE, for geographic atrophy, and EMPAVELI, targeting complement-mediated diseases such as paroxysmal nocturnal hemoglobinuria and C3 glomerulopathy. As of 2025, these products generated around $689 million in net revenue, underscoring their commercial potential for Biogen as the company pivots from its traditional focus on multiple sclerosis treatments. The company anticipates that the acquisition will bolster revenue and earnings growth, with non-GAAP earnings per share becoming accretive by 2027.

Biogen's strategic rationale centers on enhancing its exposure to immunology, nephrology, and rare diseases, a move that aligns with growing sector focus on complement-targeting therapies. These therapies regulate the complement cascade, part of the immune system, and present considerable opportunities in inflammatory and rare disease treatments—a segment where Biogen aims to solidify its market position. Additionally, the acquisition strengthens Biogen’s commercial infrastructure in nephrology, paving the way for the anticipated launch of felzartamab, an investigational kidney transplant therapy.

This acquisition reflects a broader pharmaceutical trend towards specialty therapeutics and complement biology, driven by high unmet needs and lucrative pricing potential in rare diseases. Biogen's expansion via Apellis's products could position the company more competitively as the sector witnesses intensified interest from major pharmaceutical players seeking to capitalize on these dynamics.

The transaction, conducted under Delaware law, saw 82.4% of Apellis’s shares tendered by the May 13th deadline, with the remaining shares acquired through a merger process. Apellis is no longer listed on Nasdaq, marking the conclusion of this acquisition phase. Biogen is expected to update its financial projections in its upcoming earnings release, detailing the integration's anticipated impact and key developments in the coming months.