Sanofi announced on July 24 that it will discontinue all but one ongoing trial for amlitelimab, an autoimmune asset acquired in the $1.4 billion purchase of Kymab, after the monoclonal antibody failed to show improvement over the standard of care in atopic dermatitis.
“Sanofi has determined that the totality of efficacy and safety evidence generated to date does not support further development of amlitelimab in AD,” Sanofi said in a press release. The company noted that although amlitelimab significantly reduced skin lesions and disease severity in the Phase 3 COAST-1 study last fall, it did not demonstrate “meaningful improvement” compared to current treatments.
The OX40-ligand antibody was a central part of Sanofi’s acquisition of Kymab in 2021. However, Leerink Partners wrote at the time that amlitelimab was “meaningfully inferior” to Sanofi’s existing immunology drug Dupixent during COAST-1. While a long-term extension study showed maintenance of clinical response, this was insufficient for continued development. Plans to submit amlitelimab for regulatory approval have been dropped as part of an ongoing strategic pipeline assessment.
Analysts at Leerink Partners said they were not surprised by this decision: “amlitelimab demonstrated modest efficacy and there were two cases of Kaposi’s sarcoma previously reported in clinical trials.” Sanofi confirmed with analysts that no additional cases had occurred. A spokesperson told BioSpace there are no other new pipeline changes related to this announcement, and stated, “Sanofi is working to identify the best and most appropriate path forward for all staff who have supported the development of amlitelimab in AD.”
Amlitelimab continues in a mid-stage trial for celiac disease with results expected later this year. Other indications such as hidradenitis suppurativa, alopecia areata, asthma, and scleroderma are no longer listed for development with this drug; previously it had been considered one of Sanofi’s top three pipeline assets with peak sales potential exceeding €5 billion according to a 2025 note from Leerink Partners.
This marks Sanofi's second discontinuation due to efficacy concerns within its autoimmune portfolio this summer, following termination of a Phase 3 study on another drug for chronic inflammatory demyelinating polyneuropathy announced last month after interim data suggested insufficient efficacy. The company also faces leadership changes as R&D head Houman Ashrafian departs, with Paulo Fontoura set to take over under CEO Belén Garijo.
