Sanofi (SNY) Q4 2025 earnings review
Dupixent Acceleration Masks Vaccine Volatility
Sanofi delivered a potent end to 2025, with sales growth accelerating to 13.3% (CER) in Q4, outmaneuvering the full-year average of 9.9%. The narrative is dominated by the separation of the consumer health unit (Opella) and the relentless expansion of Dupixent, which broke the €4B quarterly barrier. While headline Business EPS surged 26.7% due to margin expansion and buybacks, IFRS earnings showed a loss due to Opella deconsolidation charges. Looking to 2026, the guidance suggests a slight normalization (high single-digit sales growth), signaling that while the transformation is working, the explosive 2025 growth rates face tougher comps.
🐂 Bull Case
Sales accelerated to +32.2% in Q4 (vs +25% FY), proving that new indications (COPD, CSU) are adding layers of growth rather than just offsetting decay. It is now annualizing at over €16B.
Gross margins expanded 110bps and Business Operating Income (BOI) margins grew 100bps to 20.7%. The company is successfully leveraging its SG&A base despite heavy launch investments.
🐻 Bear Case
The Vaccines segment contracted 2.5% in Q4. While flu performed well, Beyfortus sales dropped 14.9% due to phasing/inventory timing. This lumpiness complicates the quarterly growth narrative.
While Amlitelimab looks strong, Tolebrutinib failed its primary endpoint in PPMS (MS), a significant blow to the neurology franchise's future blockbuster potential.
⚖️ Verdict: 🟢
Strong. The core thesis—shedding consumer health to focus on immunology innovation—is validated by the numbers. Dupixent's acceleration is rare for a drug of its size, offsetting vaccine lumpiness and pipeline hiccups.
Key Themes
Dupixent: Accelerating at Scale
Accelerating. Usually, drugs of this size (€15.7B FY) slow down. Dupixent did the opposite, growing 32.2% in Q4 vs 25.2% for the full year. Key drivers were the COPD launch and strong uptake in new indications like CSU and EoE. North America remains the powerhouse (+35.9%), but international growth (+25%) shows global traction.
Vaccine Segment Contraction
Reversing. After a strong year, Vaccines dipped 2.5% in Q4. The culprit was Beyfortus (-14.9%), which suffered from a high base of comparison and inventory phasing from Q3. While management cites 'better than anticipated' flu sales (+31.5%), the inability of the broader portfolio to offset Beyfortus timing is a watch item.
New Pharma Launches Delivering
Accelerating. The 'Pharma Launches' bucket (excluding Dupixent) grew 49.4% in Q4 to €1.1B. ALTUVIIIO (Hemophilia) crossed blockbuster status with €324M in Q4 (+53%). Nexviazyme (Pompe) grew 15.8%. These assets are de-risking the reliance on Dupixent.
Tolebrutinib Pipeline Failure
Negative. The PERSEUS Phase 3 study for tolebrutinib in Primary Progressive MS (PPMS) did not meet its primary endpoint. While the drug is still under review for nrSPMS, this failure limits the total addressable market and casts a shadow over the neurology pipeline's potential to deliver near-term blockbusters.
Capital Allocation Shift
Sanofi is aggressively redeploying capital following the Opella separation. They completed a €5B buyback in 2025 and announced another €1B for 2026. Additionally, the Dynavax acquisition ($2.2B) signals a commitment to bolstering the vaccine pipeline despite Q4 weakness.
Other KPIs
Improved 110bps YoY (CER). The portfolio shift toward high-margin specialty care (Dupixent, ALTUVIIIO) is structurally lifting profitability, offsetting inflation.
Up 35.8% YoY. Strong cash conversion is supporting the dividend increase (+5.1% to €4.12) and continued buybacks.
Mixed. Lantus managed +1.1% growth, but Aubagio collapsed -30.8% due to generic competition. This segment remains a drag on top-line velocity.
Guidance
Stable/Decelerating. Following the 9.9% growth in 2025 (and 13.3% in Q4), this implies a slight moderation in velocity as comps get tougher, particularly for Beyfortus and launches.
Decelerating. 2025 EPS grew 15.0%. Guiding for 'slightly faster' than high-single digits (e.g., ~9-10%) suggests less margin expansion leverage in 2026 compared to the breakout year of 2025.
Key Questions
Vaccines Volatility vs. Dynavax
Vaccines contracted in Q4 despite strong flu performance. With the Dynavax acquisition pending, how should we model the vaccine segment's growth profile in 2026—is Q4's dip purely phasing, or is there underlying demand softness in travel/endemic vaccines?
Dupixent Plateau Risk
Dupixent accelerated to 32% growth in Q4. With such massive scale (€16B run rate), where do you see the ceiling for COPD penetration in 2026, and how much of Q4's acceleration was stocking vs. true demand?
Neurology Strategy post-Tolebrutinib
With the failure of Tolebrutinib in PPMS, how does this alter the neurology franchise strategy? Are you pivoting resources to Amlitelimab and immunology, or do you seek external BD to fill the neurology gap?
Opella Deconsolidation Impact
Can you clarify the specific impact of the Opella deconsolidation on the 2026 tax rate and free cash flow conversion assumptions implied in the guidance?