LONDON – Biogen Inc. (“Biogen”, Nasdaq: BIIB) has entered into a definitive agreement to acquire public portfolio company Apellis Pharmaceuticals, Inc. (“Apellis”, Nasdaq: APLS). Apellis is a commercial-stage biotech advancing treatments for serious, complement-driven diseases. It has two FDA-approved medicines, EMPAVELI® for rare immune-mediated kidney diseases and SYFOVRE® for an immune-mediated retinal disease.
According to a statement, Apellis shareholders will each receive $41 cash per share, a transaction that values Apellis at $5.6 billion. Shareholders will also receive one contingent value right (CVR) for each Apellis share held, entitling the holder to receive two payments of $2 per share each, contingent on certain sales thresholds being met. The transaction is expected to close in the second quarter of 2026.
The acquisition price represents a 163% premium (including CVRs) to Apellis’ closing share price on 30 March, prior to the announcement. As at 28 February 2026, Apellis represented 1.1% of the Company’s NAV.
“Consistent with our strategy, this acquisition immediately advances Biogen’s ongoing transformation. The addition of Apellis expands our growth portfolio in immunology and rare disease with two approved, best-in-class medicines that complement our existing portfolio and bolsters our near-and long-term growth potential,” said Christopher A. Viehbacher, Biogen’s President and Chief Executive Officer.
“We look forward to welcoming Apellis employees to Biogen. We believe our combined capabilities and experience will allow us to maximize the potential of SYFOVRE® and EMPAVELI®, while Apellis’ talent, expertise and field capabilities will further strengthen Biogen, deepening the foundation for our growing nephrology franchise with felzartamab and serving many more patients with immune-mediated retinal disease.”
“I am incredibly proud of the Apellis team and what we have achieved, including bringing two transformational medicines – SYFOVRE® and EMPAVELI® – to patients and building an innovative pipeline leveraging our deep expertise in complement science,” said Cedric Francois, M.D., Ph.D., co-founder and Chief Executive Officer of Apellis. “With Biogen’s extensive experience with immunology and rare disease, we believe this transaction will accelerate our impact and enable us to reach more patients. This transaction represents a compelling outcome for our shareholders and a strong validation of our strategy, scientific innovation, and execution.”
Upon closing of the transaction, expected in the second quarter of 2026, the addition of Apellis is expected to add commercial products to Biogen that together recorded $689 million in revenue in 2025, and which are expected to grow at a rate in the mid-to-high teens at least through 2028.
This transaction is expected to strengthen Biogen’s revenue and EPS growth potential and is expected to be increasingly accretive to Biogen’s Non-GAAP diluted EPS starting in 2027. Importantly, the transaction is expected to meaningfully increase Biogen’s non-GAAP EPS compounded annual growth rate (CAGR) through the end of the decade. Biogen expects to finance the acquisition with a combination of cash and borrowings and believes it can fully de-lever by the end of 2027, allowing it to maintain financial flexibility for future investments.
Biogen plans to update full year 2026 guidance when it reports earnings for the first quarter of 2026.
Under the terms of the agreement, Biogen will commence a tender offer to acquire all of the outstanding shares of Apellis common stock for $41 per share in cash at closing (representing an 86% premium to the 90-day volume-weighted average stock price and a 35% premium to the 52-week high stock price) and a non-transferable CVR per share. Each CVR represents the right to receive a cash payment of $2 per share if SYFOVRE® achieves $1.5 billion in annual global net sales in any calendar year between 2027 and 2030, a right to receive an additional cash payment of $2 per share if SYFOVRE® achieves $2 billion in annual global net sales in any of these calendar years, and, if these thresholds are not met and no CVR payment is due for any of these years, but if SYFOVRE® achieves $2 billion in annual global net sales in the 2031 calendar year, a cash payment of $4 per share. Upon the successful completion of the tender offer, Biogen will acquire all remaining Apellis shares that are not tendered into the tender offer through a second-step merger at the same consideration.
The transaction, which was approved by the boards of directors of both companies, is subject to successful completion of the tender offer, customary closing conditions, and the receipt of necessary regulatory approvals.