Biogen (Nasdaq: BIIB) is making its most consequential portfolio move in years, announcing a definitive agreement to acquire Apellis Pharmaceuticals (Nasdaq: APLS) for $41.00 per share in cash — an upfront equity consideration of approximately $5.6 billion — plus a contingent value right (CVR) tied to future sales milestones for its flagship eye disease therapy. The deal closed out March with a statement: big pharma is hungry, and specialty biotech is on the menu.
The transaction carries an 86% premium to Apellis’ 90-day volume-weighted average stock price and a 35% premium to its 52-week high. It is expected to close in the second quarter of 2026.
What Biogen Is Getting
At the center of the deal are two commercialized complement-targeting therapies: SYFOVRE® (pegcetacoplan injection), approved for geographic atrophy (GA) secondary to age-related macular degeneration, and EMPAVELI® (pegcetacoplan), approved across three rare immune-mediated conditions — C3 glomerulopathy (C3G), primary IC-MPGN, and paroxysmal nocturnal hemoglobinuria (PNH).
Together, the two drugs generated $689 million in combined net product revenue in 2025, with growth expected in the mid-to-high teens annually through at least 2028. For a company navigating revenue headwinds from its legacy MS portfolio, that near-term visibility is exactly what Biogen needed.
SYFOVRE holds particular strategic weight as the first-ever approved therapy for geographic atrophy — a progressive retinal disease affecting more than five million people globally. Long-term efficacy data shows the drug can delay GA lesion progression by approximately 1.5 years in key patient populations, giving the asset durable commercial runway. The GA space is one that smaller innovators are also actively pursuing. Ocugen (Nasdaq: OCGN), is developing a gene therapy approach targeting inherited retinal diseases — the kind of differentiated, mechanism-driven science that has increasingly attracted large-cap attention.
The Nephrology Angle
Beyond the immediate revenue story, the strategic rationale runs deeper into kidney disease. Apellis brings an established nephrology sales infrastructure that Biogen intends to leverage for felzartamab, its Phase 3 kidney disease candidate with a first trial readout expected in the first half of 2027.
EMPAVELI’s rare kidney disease approvals — including the only FDA-approved treatment for pediatric patients with C3G and the first approval for post-transplant C3G recurrence — underscore how defensible rare nephrology positions can be. Two other emerging growth companies are staking ground in adjacent kidney disease spaces: Unicycive Therapeutics (Nasdaq: UNCY), developing oxylanthanum carbonate for hyperphosphatemia in chronic kidney disease patients, and Eledon Pharmaceuticals (Nasdaq: ELDN), advancing therapies focused on reducing kidney transplant rejection. The Biogen-Apellis deal reinforces that nephrology is becoming a high-value destination for large-cap dealmaking.
A Market Signal Worth Noting
The Apellis acquisition didn’t land in a vacuum. Earlier today, Eli Lilly announced a separate agreement to acquire Centessa Pharmaceuticals for up to $47.00 per share — a deal valued at approximately $7.8 billion including contingent payments — to bolster its neuroscience pipeline in sleep-wake disorders. Two major biotech acquisitions announced on the same day signals something broader: pharmaceutical companies with strong balance sheets are actively scanning for de-risked, commercially validated or late-stage assets, and they’re willing to pay premium prices to get them.
For investors tracking small and microcap biotech, that backdrop matters. Companies building real clinical differentiation in immunology, nephrology, and ophthalmology are operating in exactly the spaces that large pharma is now paying billions to enter.
CVR Structure and Financial Outlook
The CVR entitles Apellis shareholders to two potential payments of $2 per share, contingent on SYFOVRE hitting $1.5 billion and $2 billion in annual global net sales between 2027 and 2030. Biogen expects the deal to be increasingly accretive to non-GAAP diluted EPS starting in 2027, with full de-leveraging targeted by end of 2027.
