Biogen's FY25 Earnings Confirm Transition Progress Amid Guided Revenue Decline

What happened

Biogen reported FY25 earnings with non-GAAP EPS of $15.28, exceeding guidance, as growth products generated $3.3B to offset declining multiple sclerosis revenue. The company continues its transition to a portfolio anchored in rare disease and Alzheimer's therapies, such as Leqembi and Skyclarys, which improved mix quality. However, management guided for a mid-single-digit revenue decline in 2026, signaling that growth assets may not yet fully overcome MS erosion in the near term. This aligns with the DeepValue report's WAIT rating, which highlights ongoing risks from MS decline and business development charges despite cost discipline. Despite stable EPS, the guided revenue decline underscores that Biogen's path to sustainable top-line growth remains uncertain and dependent on key catalysts.

Implication

The FY25 earnings show EPS stability from cost cuts and growth products, but the 2026 revenue guidance of a mid-single-digit decline contradicts hopes for stabilization, suggesting underlying pressures persist. Rare disease and Alzheimer's therapies are expanding, yet not at a pace to fully offset MS erosion, which aligns with the DeepValue report's base case of flat revenue and high risk from MS declines. Investors must closely monitor whether Leqembi expansion and high-dose Spinraza approval can accelerate growth to meet the report's threshold of ≥3% revenue growth for a positive thesis shift. Repeated EPS guidance cuts from business development charges, as noted in the report, continue to introduce earnings volatility that could cap near-term upside. Overall, this news supports holding off on new investments until 2026 results and further quarters of launch product data provide evidence of a durable growth inflection.

Thesis delta

The news slightly shifts the thesis towards the bear case by guiding for revenue decline in 2026, rather than the flat or growth scenario needed for an upgrade. It reinforces the DeepValue report's caution that rare-disease growth must exceed 10% to offset MS declines, and investors should watch for early 2026 guidance updates to assess if launch products can sustain high growth rates. No major thesis change occurs, but the probability of downside scenarios increases if the guided decline materializes without offset from catalysts like Leqembi.