Sanofi announced it has discontinued amlitelimab in atopic dermatitis, forgoing global regulatory submissions despite positive long-term phase 3 data.
Sanofi has decided it will not submit amlitelimab, an OX40-ligand monoclonal antibody (mAb), for global regulatory review in moderate-to-severe atopic dermatitis (AD), the company announced on July 24, 2026, ending clinical development of the drug in this indication.1 The decision was made as part of an ongoing strategic assessment of Sanofi's pipeline.1
Sanofi said the totality of efficacy and safety evidence generated to date does not support further development of amlitelimab in AD.1 The decision comes despite data from the phase 3 ESTUARY long-term extension study (NCT06407934), which the company said showed long-term maintenance of clinical response without relapse in patients 12 years and older with moderate-to-severe AD, along with an emerging safety profile consistent with prior data; Sanofi concluded, however, that amlitelimab would not represent a meaningful improvement over the standard of care.1 Additional results from the amlitelimab AD program, including from ESTUARY, will be presented at a forthcoming medical meeting.1
The phase 3 program reportedly met its primary endpoint in 2 of 3 trials, according to late-breaking data presented at the American Academy of Dermatology. The combination-therapy SHORE trial produced the highest response rates of the 3 studies, with an EASI-75 response approaching 48% in the every-4-week dosing arm.2
Moderate-to-severe AD is a heterogeneous, chronic inflammatory skin disease, and Sanofi said patients and physicians continue to need additional effective treatments given the range of underlying immune mechanisms that drive the condition.1 Current AD treatment options include biologics such as dupilumab and tralokinumab and oral Janus kinase inhibitors such as upadacitinib and abrocitinib, which target distinct points along the type 2 inflammatory pathway.
The discontinuation reflects a case in which meeting statistical significance in late-stage trials did not, on its own, meet the company's stated bar for demonstrating meaningful clinical differentiation from existing standard-of-care options.
Amlitelimab (SAR445229, KY1005) is a fully human, non-T-cell-depleting mAb that blocks OX40 ligand (OX40L), a key immune regulator expressed on antigen-presenting cells.1 By selectively blocking OX40L signaling during the initiating phase of an overactive immune response, the drug is designed to normalize T-cell-mediated inflammation without depleting T cells.1
In the earlier phase 2b STREAM-AD trial, amlitelimab met its primary endpoint of percentage change in Eczema Area and Severity Index (EASI) at week 16, and significantly greater proportions of patients achieved EASI-75 and Investigator Global Assessment (IGA) scores of 0 or 1 with amlitelimab compared with placebo at week 24, with response largely maintained through week 52 among patients who continued treatment.3 Amlitelimab's upstream OX40L-blocking mechanism has been described as a potentially differentiated approach relative to downstream cytokine-targeted therapies now used across inflammatory skin disease.4
Sanofi said it will work with investigators, site teams, and regulatory authorities to wind down ongoing amlitelimab AD studies, with appropriate transition of care for all enrolled patients.1 The company is not amending its full-year 2026 financial guidance as a result of this announcement.1 Development of amlitelimab continues outside AD, including a phase 2 study in celiac disease that is ongoing, with a readout expected in the second half of 2026.1
