Sanofi is dropping efforts to win approval for its eczema drug amlitelimab in atopic dermatitis — an unusual retreat given the drug actually showed efficacy in late-stage testing.
The company concluded that amlitelimab, an OX40-ligand blocker, would not offer “meaningful improvements” over the current standard of care. While the drug demonstrated efficacy across its Phase 3 program, it missed a co-primary endpoint in the COAST 2 study, and safety flagged too: two patients developed Kaposi sarcoma, a rare cancer.
Another hit for the OX40 class
The decision compounds the troubles of the OX40 drug class, which targets an immune pathway involved in inflammatory skin disease. Kyowa Kirin previously terminated its own OX40 inhibitor, rocatinlimab, after patients also developed Kaposi sarcoma.
“Industry momentum for OX40s will likely wind down” following amlitelimab's discontinuation, alongside rocatinlimab's, said GlobalData's Tanuj Sircar.
What happens to the drug
Sanofi has also halted amlitelimab development in asthma, alopecia, and hidradenitis suppurativa. One program survives: a Phase 2 study in celiac disease continues, with results expected in the second half of 2026.
Why it matters
Eczema is a crowded, competitive market anchored by Sanofi and Regeneron's own blockbuster Dupixent — a high bar that a “me-too” mechanism has to clear. Amlitelimab's exit is a reminder that in a mature market, efficacy alone isn't enough; a new drug has to be clearly better, and safer, to be worth launching.