Apellis Pharmaceuticals (APLS) surges 136% premarket on Biogen’s $5.6B acquisition — March 31, 2026

NEW YORK, March 31, 2026 — Apellis Pharmaceuticals (Nasdaq: APLS) surged 136% in premarket trading on March 31, 2026, reaching $40.35 — effectively pricing at the deal value — after Biogen (Nasdaq: BIIB) agreed to acquire all outstanding shares of Apellis for $41.00 per share in cash at closing, representing an upfront equity consideration of approximately $5.6 billion. The offer represents a 140% premium to Apellis’s Monday closing price of $17.09, an 86% premium to the 90-day volume-weighted average stock price, and a 35% premium to the 52-week high — signalling that Biogen moved aggressively to secure a deal it viewed as strategically essential rather than opportunistically attractive. Session volume exceeded 33 million shares, approximately 12 times APLS’s average daily volume of 2.78 million, confirming the authenticity of the move and ruling out thin-market exaggeration. In addition to the $41 cash consideration, Apellis shareholders will receive a non-transferable contingent value right entitling holders to two payments of $2 per share each — for a total potential CVR of $4 per share — contingent on specific global net sales milestones for SYFOVRE, Apellis’s treatment for geographic atrophy.

What Biogen is acquiring — SYFOVRE, EMPAVELI, and the nephrology platform

The Apellis acquisition gives Biogen immediate access to two approved commercial assets with meaningful and growing revenue. SYFOVRE (pegcetacoplan) is approved by the FDA for the treatment of geographic atrophy (GA) secondary to age-related macular degeneration — one of the leading causes of blindness globally and a condition that affects an estimated 5 million people in the United States alone. SYFOVRE became the first approved treatment for GA when the FDA granted approval in 2023, establishing Apellis as the pioneer in a market that Regeneron and Annexon are also pursuing. The drug targets the complement pathway — an immune system mechanism — and its approval validated Apellis’s platform technology for addressing complement-mediated diseases. EMPAVELI (pegcetacoplan for systemic use) won FDA approval in 2021 for paroxysmal nocturnal hemoglobinuria (PNH), and subsequently received approval for two rare kidney diseases: complement 3 glomerulopathy (C3G) and primary immune complex membranoproliferative glomerulonephritis (IC-MPGN), adding a nephrology footprint that is directly synergistic with Biogen’s stated strategic ambition to expand into kidney disease.

The two commercial assets generated combined net product revenue of approximately $689 million in 2025, and the companies guided for growth in the mid-to-high teens at least through 2028 — implying approximately $1.5 billion in 2030 revenue by analyst consensus. Fierce Pharma noted that the Apellis commercial team is approximately 350 strong — a nephrology sales force that Biogen CEO Chris Viehbacher specifically cited as a critical strategic asset, noting that “hiring in nephrology is actually not so easy. It’s a competitive space” and that retaining Apellis’s commercial infrastructure was a key deal rationale alongside the pipeline and product portfolio.

Why Biogen needed this deal — pipeline maturity, Alzheimer’s uncertainty, and the nephrology pivot

Biogen has been navigating a pivotal strategic period. The company’s Alzheimer’s pipeline — including BIIB080, whose 2026 Phase 2b readout is anticipated by analysts and investors as a potential breakthrough — carries significant uncertainty even in a best-case outcome, with executives warning that a successful readout would still require “many more steps before the therapy could reach the market.” That uncertainty creates a business model vulnerability: Biogen needs near-term revenue growth to bridge toward its longer-dated pipeline catalysts, and the Apellis acquisition delivers exactly that. The deal is expected to be increasingly accretive to non-GAAP diluted EPS starting in 2027 and to “meaningfully increase Biogen’s non-GAAP EPS compound annual growth rate through the end of the decade” — language that reflects management’s confidence that the $689 million 2025 revenue base is a reliable and growing foundation.

The nephrology strategic expansion is the deal’s forward-looking logic. Biogen already has felzartamab — its own kidney disease candidate — in development, but lacks the commercial infrastructure and specialist sales force to launch a nephrology asset effectively at scale. Apellis’s 350-person commercial team, built around the C3G and IC-MPGN indications, provides precisely that infrastructure. Because there are no indication overlaps between Biogen’s existing portfolio and Apellis’s kidney disease franchise, BMO analysts noted they see no meaningful FTC regulatory risk — a relatively clean deal from an antitrust perspective, reducing one of the primary execution risks that typically accompany healthcare M&A of this scale. The healthcare sector’s M&A environment in 2026 — driven by pending patent cliffs, the post-GLP-1 windfall redeployment by large pharma, and compressed biotech valuations following the Iran-driven market correction — has created acquisition opportunities at prices that were less accessible six months ago.

Deal structure — tender offer, no financing condition, and the path to closing

The transaction is structured as a tender offer followed by a Section 251(h) short-form merger under Delaware law — a structure that avoids requiring a separate stockholder vote once Biogen has acquired a majority of Apellis’s outstanding shares through the tender offer. The absence of a financing condition is notable: it removes one of the most common deal-break risks in acquisition transactions, reflecting Biogen’s financial capacity to complete the acquisition without contingent capital markets activity. Closing conditions include a minimum tender threshold above 50% of outstanding shares and the expiration of Hart-Scott-Rodino antitrust waiting periods. Support agreements have been signed by key insiders and Morningside Venture Investments, collectively holding a meaningful percentage of outstanding shares, reducing the risk of a competing bid or shareholder opposition derailing the deal. Biogen said it would update its full-year 2026 guidance when it reports Q1 2026 earnings, incorporating the acquisition’s financial impact into the forward outlook.

The deal’s timing is also notable from a market structure perspective. APLS had been trading at $17.09 on Monday March 30 — well below its 52-week high and significantly below the $41 acquisition price — reflecting the broad biotech sector compression that accompanied the Iran war’s risk-off environment in March 2026. The Dow and Nasdaq had confirmed corrections, the VIX had closed above 30, and risk appetite across growth and speculative assets had contracted sharply. Biogen’s decision to move aggressively in that environment — paying a 35% premium even to the 52-week high — signals either that the company had proprietary conviction about SYFOVRE’s competitive durability that was not reflected in the depressed market price, or that it was unwilling to allow a recovery in biotech sentiment to raise the acquisition cost after the Iran conflict resolves. Readers seeking context on how premarket surges like APLS’s 136% gain develop and what volume confirmation signals authenticity are covered in PreMarket Daily’s education series.

Sector read-through — a record M&A session for pharma and what it signals about valuations

March 31, 2026 produced the most concentrated single-day healthcare sector M&A announcements of the year: Biogen-Apellis ($5.6B), Eli Lilly-Centessa ($7.8B), and both targeting complementary healthcare niches — ophthalmology/nephrology and sleep-wake neurology respectively. The two deals collectively signal that large-cap pharma balance sheets — swelled by GLP-1 revenues in Lilly’s case and bolstered by maturing commercial franchises in Biogen’s — are being deployed opportunistically into a biotech market that has been compressed by the Iran war’s broader risk-off effect. The message to mid-cap and small-cap biotech investors is unambiguous: acquirers are active, premiums are substantial (140% for APLS, 38% for CNTA upfront), and the current valuation compression creates acquisition opportunities that strategic buyers are willing to act on even in uncertain macro conditions. Whether additional healthcare deals follow in April — particularly among other complement pathway biotechs, orexin-targeting companies, and nephrology specialists — will be one of the sector’s primary tracking questions heading into Q2.