Sanofi is walking away from amlitelimab in atopic dermatitis, the second autoimmune program it’s killed this summer.
The company said Thursday that “the totality of efficacy and safety evidence generated to date does not support further development of amlitelimab in AD,” pulling the plug on its planned regulatory submission that was supposed to hit FDA desks in the second half of this year. The OX40-ligand antibody showed durable clinical response in a long-term extension study, but that wasn’t enough against Sanofi’s own blockbuster, Dupixent.
This is the drug Sanofi paid up to $1.45 billion for. The 2021 Kymab acquisition was built around KY1005, rebranded amlitelimab, with Sanofi once pitching peak sales above €5 billion and ranking it among its top three pipeline assets.
I’ve watched enough pipeline resets to know the tell here: when a company shelves an asset “as part of an ongoing strategic assessment” without touching guidance, the write-down is already priced in internally. Sanofi confirmed no other pipeline changes accompany this one, and full-year 2026 guidance stands. But pair this with June’s complement-inhibitor discontinuation in chronic inflammatory demyelinating polyneuropathy, and the pattern is two failed autoimmune bets in one summer, right as Sanofi preps for Dupixent’s 2031 patent cliff.
Amlitelimab isn’t dead everywhere. A mid-stage celiac disease trial reads out in the second half of 2026, and that’s now the whole ballgame for the Kymab deal’s return on investment. Sanofi hasn’t said whether staff tied to the AD program will be reassigned or cut.
— Rebecca Lauren