WALTHAM, Mass., March 31, 2026, 10:19 EDT
Biogen said Tuesday it’s acquiring Apellis Pharmaceuticals in a cash deal valued near $5.6 billion, offering Apellis shareholders $41 per share upfront and additional potential payouts depending on Syfovre sales milestones. Apellis stock shot up to $40.32 after the open; Biogen shares edged down to $178.25.
The deal arrives as both companies face inflection points. Biogen needs new growth drivers with its established multiple-sclerosis drugs losing steam, while Apellis delivers two rare-disease therapies that pulled in $689 million in 2025 and are projected to increase at a mid-to-high teens pace through 2028.
Syfovre is used to treat geographic atrophy, a severe type of age-related macular degeneration that leads to permanent vision loss. Empaveli, meanwhile, has approvals in paroxysmal nocturnal hemoglobinuria—a rare blood condition—and two uncommon kidney disorders. Apellis also comes with a U.S. nephrology sales infrastructure, which will be in place as Biogen gets ready for Phase 3 results on its kidney-disease drug felzartamab, expected in the first half of 2027. Barclays’ Emily Field called the deal a “signal of confidence” ahead of those updates, while Brian Abrahams from RBC Capital Markets told Bloomberg the move might offer a “much-needed near-term boost to earnings.” Apellis Pharmaceuticals, Inc.
Apellis shareholders are set to get $41 per share in cash, plus a non-transferable contingent value right (CVR) worth up to an extra $4 per share if Syfovre hits certain annual global sales goals. According to the companies, the cash portion alone comes in at an 86% premium over Apellis’s 90-day volume-weighted average, and roughly a 140% premium compared to Monday’s closing price.
In February, Apellis posted 2025 net product revenue of $689 million. Syfovre accounted for $587 million of that total, with Empaveli bringing in $102 million. Syfovre grabbed about 60% of the U.S. geographic atrophy market, and injections climbed 17% year-on-year. The company aims to file for a prefilled syringe in the first half of 2026.
Christopher Viehbacher, Biogen’s chief executive, called the acquisition part of the company’s “ongoing transformation.” Apellis CEO Cedric Francois said the transaction would “accelerate our impact.” Apellis develops medicines targeting the complement system—a key component of the immune response—offering Biogen a wider reach into nephrology and rare diseases. Apellis Pharmaceuticals, Inc.
This isn’t a straightforward play. Syfovre faces off against Astellas Pharma’s Izervay in the geographic atrophy space, but it comes with baggage: labels warning of retinal vasculitis and retinal vascular occlusion—basically, inflammation or blocked blood vessels in the eye. Trials also showed increased rates of wet AMD, the serious version of macular degeneration. For the acquisition to move ahead, the tender offer must go through and regulators still need to sign off, with the deal aiming for a second-quarter close.
Biogen expects the acquisition to add more to adjusted earnings per share starting in 2027, with further details on its full-year 2026 outlook coming when it posts first-quarter numbers.
