Biogen Inc. (BIIB) on Wednesday revised its full-year 2026 profit guidance downward, even as first-quarter earnings surpassed analyst expectations, driven by a sharp increase in sales of its Alzheimer's treatment Leqembi and newer rare-disease therapies.
The Cambridge, Massachusetts-based biotech firm now expects adjusted earnings for 2026 in the range of $14.25 to $15.25 per share, trimming $1 from both ends of its previous forecast. The company attributed the reduction to acquired in-process research and development charges stemming from recent acquisitions—costs associated with licensing or acquiring drug programs that have not yet reached commercialization.
For the first quarter, Biogen reported revenue of $2.48 billion, a 2% increase year-over-year. Adjusted earnings came in at $3.57 per share, well above the consensus estimate of $2.77 per share among analysts surveyed by Reuters. Revenue also topped expectations of $2.26 billion.
Leqembi, the Alzheimer's drug co-developed and co-marketed with Japan's Eisai Co., remained the standout growth driver. Global in-market sales reached approximately $168 million, a 74% surge from the same period last year. U.S. sales accounted for $86 million of that total. The strong performance marks a notable acceleration following a slower-than-expected launch, as physicians and payers weighed the drug's efficacy, cost, and ongoing safety monitoring requirements.
The Alzheimer's market is still in its early stages of development, and Biogen faces competition from Eli Lilly's Kisunla, which received FDA approval in July 2024 for adults with mild cognitive impairment or mild dementia due to Alzheimer's—the same early-stage patient population targeted by Leqembi.
Biogen's CEO Christopher Viehbacher said the company has "significantly advanced" its transformation, highlighting progress on both commercial and pipeline fronts, as well as the planned acquisition of Apellis Pharmaceuticals. The deal, valued at roughly $5.6 billion upfront, would bring in two approved drugs—Empaveli and Syfovre—in immunology, rare kidney disease, and retinal disease. If completed, Biogen expects the transaction to begin boosting adjusted earnings in 2027. The company will revisit its financial outlook for the acquisition with its second-quarter report.
Other product lines delivered mixed results. Multiple sclerosis products generated $958 million in revenue, essentially flat year-over-year. Rare-disease revenue declined to $557 million, pressured by a 12% drop in Spinraza sales. However, Skyclarys revenue grew 22% to $151 million, and Qalsody more than doubled to $33 million. Biogen's so-called growth products—which include Skyclarys, Qalsody, Zurzuvae, Vumerity, Spinraza, and the Leqembi partnership—rose 12% year-over-year. Zurzuvae, co-marketed with Supernus, contributed $55 million.
Despite the quarterly beat, Biogen's overall revenue is projected to decline by a mid-single-digit percentage in 2026, as continued erosion in multiple sclerosis drug sales (excluding Vumerity) offsets growth elsewhere. The company is urging investors to focus on product momentum rather than the reduced earnings outlook, a message that Wednesday's results provided more support for than in recent quarters.
