Apellis Pharmaceuticals, Inc. (APLS) shares surged 135.69 percent, up $23.19 to $40.28 on Tuesday, after Biogen Inc. (BIIB) agreed to acquire all outstanding Apellis shares for $41.00 per share in cash, valuing the deal at approximately $5.6 billion. Apellis shareholders will also receive a nontransferable contingent value right that could deliver two additional $2 per share payments tied to annual global net sales targets for SYFOVRE.
The stock is currently trading at $40.28, sharply above its previous close of $17.09, after opening at $40.39 on the Nasdaq. Shares traded in a narrow range of $40.25 to $40.45 during the session, with volume surging to 40.81 million shares, far above the average daily volume of 2.78 million.
The acquisition adds Apellis' commercialized therapies EMPAVELI and SYFOVRE to Biogen's portfolio, with combined 2025 net sales of $689 million and projected growth in the mid-to-high teens through 2028. Both medicines are approved by the U.S. Food and Drug Administration for rare immune and retinal diseases, strengthening Biogen's immunology and rare disease franchise.
Apellis' 52-week range is $16.10 to $40.45.
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