BIIBHealthcareBiotech·Sep 3, 2026·6 min read

[BIIB] Biogen Thesis 2026: New Growth Portfolio Offsets Accelerating Multiple Sclerosis Decline

Biogen FY25 revenue $9.81B (+1%); op income $1.88B (-25%); NI $1.29B (-21%); EPS $8.83. Growth products $3.3B (+19% YoY) — flagship inflection: LEQEMBI + SKYCLARYS + ZURZUVAE + QALSODY each >$1B cumulative since launch. LEQEMBI 60% anti-amyloid market share. SKYCLARYS Q4 $133M (+30%); 34 markets globally. ZURZUVAE doubled FY25 sales. SPINRAZA Q4 $356M. VUMERITY Q4 $181M. MS franchise $3B but declining (TECFIDERA generic erosion EU; TYSABRI biosimilar pressure). FY26 guide: revenue mid-single-digit decline; non-GAAP EPS $15.25-$16.25; gross margin consistent; OpEx consistent.

Biogen 2025-26: Growth Products $3.3B (+19%), MS -Mid-Teens

FY25 revenue $9.81B (+1%); op income $1.88B (-25%); NI $1.29B (-21%); EPS $8.83 (-21%). Growth products $3.3B (+19%); 4 launch products >$1B revenue. LEQEMBI Q4 $134M (Eisai-booked). SKYCLARYS Q4 $133M (+30%). VUMERITY Q4 $181M. ZURZUVAE strong. Anti-CD20 Q4 $521M (+12%). FY26 guide: revenue mid-single decline; non-GAAP EPS $15.25-$16.25.

Key takeaways

  • Growth products $3.3B FY25 (+19%) — a milestone. LEQEMBI + SKYCLARYS + ZURZUVAE + QALSODY each exceeded $1B cumulative since launch. Growth products in Q4 exceeded MS revenue (excluding VUMERITY) — the portfolio rotation flagship moment.
  • MS franchise still $3B but declining. TYSABRI + VUMERITY + TECFIDERA all in decline (TECFIDERA generic erosion in Europe; biosimilar pressure on natalizumab). FY26 MS ex-VUMERITY -mid-teens.
  • LEQEMBI is the Alzheimer's anchor — 60% market share. Subcutaneous formulation (PDUFA May 24); blood-based biomarkers; international expansion. Q4 booked end-market $134M (+1054% reflects accounting reset on Eisai split). Sustained momentum.
  • Pipeline activity picked up. Felzartamab Phase 3 TRANSCEND (AMR); Litifilimab breakthrough designation (cutaneous lupus); Salanersen Phase 3 (SMA); Alcyone Therapeutics acquisition (ASO improvement); Vanqua + Dara Therapeutics collaborations; BIIB142 IRAK4 degrader.
  • FY26 EPS $15.25-$16.25 conservative — up from $15.50-16.00 FY25 raise. Mid-single revenue decline + cost discipline + Fit for Growth $1B savings ($800M net) ongoing.

Business

Biogen Inc. is a US biopharma focused on neurological + rare disease. Three product franchises:

  • Multiple Sclerosis (MS) Franchise (~31% of revenue, declining). TECFIDERA (generic erosion EU); TYSABRI ($398M Q4 — biosimilar pressure); VUMERITY ($181M Q4 — growth); plaster: $3B FY25 expected -mid-teens FY26 ex-VUMERITY.
  • Rare Disease + Launch Products (~33%). SKYCLARYS (Friedreich's ataxia) — Q4 $133M (+30%); 34 markets globally. ZURZUVAE (postpartum depression) — strong growth. SPINRAZA (SMA) — Q4 $356M; high-dose Japan launch. QALSODY (ALS).
  • Anti-CD20 (~21%). Royalties from Roche Ocrevus + RAPIVAB. Q4 $521M (+12% YoY).
  • Other / Contract Manufacturing (~15%). $300M expected FY26 contract manufacturing revenue (each half).

Strategic moves FY25:

  • LEQEMBI: 60% anti-amyloid market share; subcutaneous formulation (PDUFA May 2026)
  • SKYCLARYS: 30 → 34 markets globally; Brazil approval; global launch ex-Asia
  • ZURZUVAE: revenue doubled in 2025
  • SPINRAZA: high-dose launch Japan
  • iClick: PDUFA date May 24
  • Litifilimab: FDA breakthrough designation cutaneous lupus
  • Alcyone Therapeutics acquired (improved ASO patient injection experience)
  • Vanqua Bio collaboration (C5aR1 antagonist)
  • Dara Therapeutics collaboration
  • Fit for Growth: $1B gross savings / $800M net savings on track

FY25 financial performance

Metric (FY)2022202320242025
Revenue ($B)10.179.849.689.81
Revenue YoYn/a-3%-2%+1%
Op income ($B)2.892.102.491.88
Op margin28.4%21.3%25.7%19.1%
Net income ($B)3.051.161.631.29
Diluted EPS ($)20.877.9711.198.83
Non-GAAP EPS ($)n/an/a~16.5~16.0
FCF ($B)1.141.242.522.05
Capex ($M)-240-311-360-154
Total debt ($B)6.617.346.636.95
Buyback ($M)-750000

Op income $1.88B FY25 (-25% vs $2.49B FY24) reflects pipeline + commercial investment + competitive pressures. Non-GAAP EPS roughly flat to FY24 reflects Fit for Growth + cost discipline offsetting top-line decline.

The growth-product transition is the structural story — getting the new franchises to compound while MS declines.

Capital allocation

  • Capex: $-154M FY25 (-57% YoY). Capacity needs moderating.
  • Dividends: $0 (suspended).
  • Buybacks: $0 (vs $-750M FY22).
  • M&A: Alcyone Therapeutics; Vanqua Bio; Dara collaboration.
  • Debt: $6.95B (+5% YoY).
  • FCF: $2.05B (-19% YoY).

FY26 outlook (per Q4 2025 call, 2026-02-06)

FY26 frameworkDetail
Total revenueMid-single-digit decline vs FY25
MS product (ex-VUMERITY)-mid-teens
Contract manufacturing revenue~$300M each half ($600M total)
Gross marginRoughly consistent with FY25
Core OpExRoughly consistent with FY25; Q1 +10% phasing
Non-GAAP diluted EPS$15.25 to $16.25

Implied FY26 revenue ~$9.3B (down from $9.81B FY25). Operating leverage holds via Fit for Growth + portfolio mix shift. Conservative guide given dynamic environment + multiple PDUFA dates.

Key risks

  • MS biosimilar / generic competition. TECFIDERA Europe generic erosion; TYSABRI biosimilar pressure. FY26 -mid-teens MS ex-VUMERITY decline already factored.
  • LEQEMBI launch trajectory. Subcutaneous PDUFA May 2026; blood-based biomarker reimbursement uncertainty; CMS dynamics.
  • Pipeline read-out outcomes. Multiple Phase 3 readouts + PDUFA dates in 2026 — clinical risk binary.
  • Contract manufacturing. $600M revenue includes seasonality; not core to franchise.
  • Eisai arbitration / commercialization. LEQEMBI commercial split arbitration with Eisai in Europe ongoing.
  • CMS / Medicare reimbursement. Blood-based biomarker reimbursement + Medicare drug price negotiation impact.

Bottom line

BIIB FY25 is the portfolio inflection year: growth products $3.3B (+19%), MS still $3B but declining, LEQEMBI 60% market share + subcutaneous PDUFA May 2026, SKYCLARYS 34 markets / +30%, ZURZUVAE doubled. FY26 -mid-single revenue + non-GAAP EPS $15.25-$16.25 conservative on multi-PDUFA / pipeline year. Fit for Growth $1B savings cushion. Risks are MS decline timing + LEQEMBI execution + pipeline outcomes + reimbursement. Quality biotech mid-portfolio rotation; the question is when growth products outpace MS decline absolutely.

Citations

  • Biogen Inc. FY25 Form 10-K (filed February 2026, SEC EDGAR).
  • BIIB Q4 2025 earnings call, 2026-02-06 — growth products $3.3B (+19%); 4 products >$1B; LEQEMBI Q4 $134M booked by Eisai (+1054% vs Q3); SKYCLARYS Q4 $133M (+30%); FY26 guide ($15.25-$16.25 EPS, mid-single decline).
  • BIIB Q3 2025 earnings call, 2025-10-30 — LEQEMBI subcu launched; SKYCLARYS 34 markets; Litifilimab Phase 3 fully enrolled; Alcyone Therapeutics acquired.
  • BIIB Q2 2025 earnings call, 2025-07-31 — launch products $252M Q2 (+91% YoY); LEQEMBI U.S. +20% QoQ; ZURZUVAE +213% YoY; FY EPS raised $15.50-$16.
  • BIIB Q1 2025 earnings call, 2025-05-01 — MS franchise -11% YoY; ZURZUVAE 10K women treated; LEQEMBI EU approval + IV maintenance; BIIB080 Fast Track.
  • Internal financial_statements view (consolidated annual + cash flow + capital structure).
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