Biogen Inc. finalized its acquisition of Apellis Pharmaceuticals on Thursday, marking the end of Apellis's tenure as an independent publicly traded company on the Nasdaq. The Waltham, Massachusetts-based firm is now a wholly owned subsidiary of Biogen, with its shares ceasing to trade following the completion of the tender offer and merger.
Under the terms of the deal, Apellis shareholders receive $41 per share in cash, along with a non-transferable contingent value right (CVR) linked to future sales of Syfovre. The cash component of the offer and merger is valued at approximately $5.3 billion, excluding fees and any potential CVR payments.
Biogen gains immediate access to two commercial-stage therapies: Syfovre, approved for geographic atrophy secondary to age-related macular degeneration, and Empaveli, indicated for rare complement-mediated kidney diseases such as C3 glomerulopathy and primary immune-complex membranoproliferative glomerulonephritis. Combined net product revenue from these drugs reached $689 million in 2025.
The acquisition was financed in part through $2 billion in unsecured term loans, split evenly between a $1 billion 364-day tranche and a $1 billion two-year tranche. Biogen drew the full facility on May 13, according to regulatory filings.
Apellis's latest quarterly results underscore the rationale for the deal. For the three months ended March 31, the company reported total revenue of $268.3 million and net income of $18.7 million, reversing a year-ago loss. U.S. product sales totaled $192.0 million, with Syfovre contributing $150.7 million and Empaveli adding $41.3 million.
Biogen's stock fell 2.98% to $198.43 on the Nasdaq shortly after the announcement, while Apellis shares last traded at $41.03 before being halted. Biogen plans to revise its financial outlook when second-quarter results are released in July.
CEO Christopher Viehbacher has highlighted the value of Apellis's kidney franchise, with analysts at BMO Capital noting the deal could significantly alter perceptions of Biogen's near-term revenue growth. The company also expects Apellis's nephrology commercial infrastructure to support felzartamab, a Biogen kidney drug currently in Phase 3 development with first data expected in the first half of 2027.
Competitive pressures remain. Syfovre faces Astellas' Izervay in geographic atrophy, with new data showing Izervay slowed disease progression and, for some patients, extended the ability to maintain driver's licenses. In rare kidney disease, Novartis' Fabhalta received Health Canada approval on May 1 for adults with C3G, citing reductions in proteinuria.
The CVR component offers additional payments if Syfovre achieves annual global net sales of $1.5 billion and $2 billion in specified years, though Biogen has cautioned that there is no guarantee these milestones will be met. Safety concerns also persist, with Syfovre carrying warnings for retinal vasculitis and retinal vascular occlusion, conditions that can lead to significant vision loss.
