Sanofi axes two more inflammatory-disease drugs

Why it matters: The decisions remove two externally sourced drugs from Sanofi’s immunology pipeline, days after the French pharmaceutical group also abandoned amlitelimab, the eczema antibody obtained through its $1.1 billion acquisition of UK biotech Kymab. The decision was announced as part of Sanofi’s Q2 2026 financial results.

Zoom in: Sanofi and Regeneron will stop developing itepekimab in chronic obstructive pulmonary disease (COPD) after reassessing two Phase 3 trials reported in May 2025.

• AERIFY-1 met its primary endpoint, reducing moderate or severe COPD exacerbations by 27% after 52 weeks when administered every two weeks. However, the similarly designed AERIFY-2 trial missed its primary endpoint, producing reductions of only 2% and 12% with the two dosing schedules.
• Sanofi also pointed to changes in the competitive landscape. Since the Phase 3 programme began, Sanofi’s own Dupixent and GSK’s Nucala have become approved COPD biologics, while Verona Pharma’s introduced its inhaled treatment ensifentrine in 2024 to the market, adding a new non-steroidal maintenance option for COPD, all raising the evidence and commercial bar for itepekimab after it produced inconsistent results across two pivotal trials.

Backstory: Itepekimab is an antibody targeting IL-33 that was invented by Regeneron using its VelocImmune platform and developed through the companies’ longstanding antibody collaboration with Sanofi.

• Sanofi and Regeneron had expanded the programme beyond COPD into chronic rhinosinusitis. This included two Phase 3 trials in patients with nasal polyps and a Phase 2 study in patients without nasal polyps.

What’s next: Sanofi said all itepekimab development will be discontinued, including every study in chronic rhinosinusitis.

Meanwhile: Sanofi is also terminating development of balinatunfib, an oral inhibitor designed to block signalling through tumour necrosis factor receptor 1, or TNFR1.

• Interim analyses of separate Phase 2 trials in Crohn’s disease and ulcerative colitis failed to meet Sanofi’s internal efficacy expectations on clinical endpoints and/or the primary endpoint of clinical remission. Both studies will stop, along with the wider balinatunfib programme.

Catch up quick: Previously known as SAR441566, balinatunfib was identified through a research collaboration between Sanofi and Belgian pharmaceutical company UCB. Its discovery built on a series of small-molecule TNF inhibitors initially developed by UCB before Sanofi moved the drug into clinical testing.

• The oral therapy had previously produced mixed results in rheumatoid arthritis. A Phase 2 trial missed its primary ACR20 endpoint (20% improvement in RA symptoms), although Sanofi said at the time that deeper-response measures suggested clinical activity and continued evaluating the drug in other TNF-driven diseases.
• Balinatunfib had already suffered a Phase 2 psoriasis failure in 2025, prompting Sanofi to abandon monotherapy development in that indication. However, the company continued testing the drug in other inflammatory diseases. The latest decision ends those remaining studies and the programme as a whole.

The big picture: The two decisions follow Sanofi’s July 24 announcement that it would not seek approval for amlitelimab in atopic dermatitis. Although a long-term Phase 3 extension study supported maintenance of response, Sanofi concluded that the antibody would not offer a meaningful improvement over existing treatments. All three programmes are now being removed as part of Sanofi’s ongoing strategic review of its research pipeline.