Biogen Sees Growth in Legacy MS Franchise and New Launches, Updates Financial Outlook

Biogen, a leading pharmaceutical company focused on neurological disorders, has reported positive third-quarter results and updated its financial guidance for 2025. The company's performance reflects a resilient multiple sclerosis (MS) franchise and growing momentum in its newer product launches, signaling a potential turnaround after years of sales declines.

Strong Q3 Performance and Updated Outlook

Biogen reported third-quarter sales of $2.5 billion, representing a 3% year-over-year growth and surpassing consensus estimates of $2.3 billion. This performance has led the company to revise its 2025 financial guidance, now projecting 1% growth compared to the previously anticipated flat projection. The updated outlook marks a significant improvement from the initial expectation of a mid-single-digit decline at the start of the year.

CEO Chris Viehbacher attributed the growth to "an awful lot of market creation" focused on recent product launches, including the Alzheimer's disease drug Leqembi, Friedreich's ataxia treatment Skyclarys, and postpartum depression medication Zurzuvae.

Legacy MS Franchise Holds Strong Amid New Product Growth

Despite facing generic pressure and increased competition from anti-CD20 therapies, Biogen's legacy multiple sclerosis franchise demonstrated resilience with 1% year-over-year growth. The MS product portfolio remains the top revenue contributor, generating $1 billion in total sales for the quarter and maintaining Biogen's position as the market leader in this therapeutic area.

While analysts at William Blair do not view the MS franchise as a continued growth driver, its performance has exceeded expectations for two consecutive quarters. This stability in the face of market challenges has played a crucial role in supporting Biogen's updated financial outlook.

New Product Momentum and Strategic Initiatives

Biogen's newer products drove 67% growth over the quarter, with particular focus on Leqembi, co-developed with Eisai. The Alzheimer's treatment saw 82% year-over-year growth to $121 million in global third-quarter sales, accompanied by a 14% quarterly increase in its U.S. prescriber base. Leqembi has maintained its position as the top prescribed anti-amyloid therapy, outperforming Eli Lilly's rival drug Kinsunla, which reported $70 million in third-quarter sales.

The company is also seeing promise in other recent launches. Zurzuvae for postpartum depression is "performing above expectations," while Skyclarys for Friedreich's ataxia has expanded to 34 countries. Additionally, Biogen is awaiting an FDA decision by April 3, 2026, on a high-dose version of its spinal muscular atrophy medication Sprinraza, following a recent manufacturing-related rejection.

As part of its "new Biogen" initiative, the company is diversifying beyond neuroscience into the immunology space. This strategic shift includes the recent acquisition of Vanqua Bio for up to $1 billion, adding a preclinical oral C5aR1 antagonist to complement Biogen's in-house izastobart, currently being evaluated as a potential lupus treatment.