Press Release: Sanofi announces decision not to submit amlitelimab in atopic dermatitis for global regulatory reviews

Sanofi today announced the discontinuation of clinical development of amlitelimab, an OX40-ligand monoclonal antibody, in moderate-to-severe atopic dermatitis (AD). This decision not to submit for global regulatory reviews was made as part of an ongoing strategic assessment of the pipeline. Sanofi has determined that the totality of efficacy and safety evidence generated to date does not support further development of amlitelimab in AD. While the ESTUARY phase 3 long-term extension study (clinical study identifier: NCT06407934 ) showed long-term maintenance of clinical response without relapse in patients aged 12 years and older with moderate-to-severe AD and an emerging safety profile that builds on previous data, amlitelimab would not represent a meaningful improvement to the standard of care for patients with AD. Additional results from the amlitelimab development program in AD, including from the ESTUARY study, will be presented at a forthcoming medical meeting. Patients and their physicians need additional effective treatments due to the heterogeneity of underlying immune mechanisms that contribute to AD, and Sanofi remains committed to pursuing advances in inflammatory skin conditions. Sanofi is deeply grateful to the patients, caregivers, and investigators who supported the development of amlitelimab in AD, including in the ESTUARY study. Sanofi will work closely with investigators, site teams, and regulatory authorities to ensure a wind-down of ongoing amlitelimab AD studies, with appropriate transition of care for all enrolled patients. Sanofi is not amending its full-year 2026 guidance as a result of this announcement. About amlitelimab Amlitelimab (SAR44229, KY1005) is a fully human, non-T cell depleting monoclonal antibody that blocks the OX40L, a key immune regulator. With its novel mechanism of action, amlitelimab selectively blocks OX40L signaling during the inflammatory prequel, the initiating phase of an overactive immune system, to potentially normalize T-cell-mediated inflammation without T-cell depletion. The phase 2 study of amlitelimab in celiac disease is ongoing and expected to readout in the second half of 2026.