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Sanofi has discontinued development of OX40L-targeting amlitelimab for atopic dermatitis, following the heels of Kyowa Kirin's similar rocatinlimab discontinuation.
Sanofi has announced it will discontinue the clinical development of amlitelimab for moderate-to-severe atopic dermatitis, citing the investigational therapy’s lack of sufficient clinical advantage over existing standards of care.1
The July 24 decision has occurred despite positive long-term results from the company’s phase 3 SHORE and COAST development programs for amlitelimab.2 The move by Sanofi follows an internal strategic review the research pipeline. Now, the company will no longer pursue global regulatory submissions for amlitelimab in the atopic dermatitis treatment space.
Amlitelimab was designed as a fully human monoclonal antibody, inhibiting the OX40 ligand (OX40L), an immune signaling molecule involved in the early activation of T-cell–mediated inflammation.2 The selective blocking of this pathway without depleting T cells was done to modulate immune responses upstream in the inflammatory cascade.
The discontinuation follows split opinions in the field over whether amlitelimab's non-depleting mechanism would spare it from the safety concerns that ended rocatinlimab's development. HCPLive previously reported on this divide after Kyowa Kirin and Amgen halted rocatinlimab's program in March 2026 following identification of Kaposi's sarcoma cases across that trial.³ At the time, dermatologists were split on whether the signal reflected a risk specific to rocatinlimab's T-cell-depleting design or a broader class effect tied to OX40 pathway modulation itself.
Eingun James Song, MD, and April W. Armstrong, MD, MPH, argued amlitelimab's ligand-blocking, non-depleting mechanism made a similar safety profile less likely, pointing to amlitelimab's favorable adverse event data at the time. Jennifer Soung, MD, was more skeptical, characterizing the Kaposi's sarcoma signal as a likely class effect regardless of mechanism and questioning whether any OX40-targeted therapy could clear a high enough efficacy and safety bar to unseat existing biologics.³
On the mechanistic distinction between the 2 agents, Soung was direct: "I don't think there's a difference. It's a class effect, and I was always worried about targeting T cells in immunology, so I'm not sure it's the best target."
In the company’s announcement, they described the determination to discontinue as based upon an assessment of the overall efficacy and safety data of the drug collected throughout this development program.1 Although results from the ongoing ESTUARY phase 3 long-term extension trial suggested patients aged 12 years and older maintained clinical responses over time without relapse, Sanofi decided the medication would not provide a meaningful improvement compared with currently available options for moderate-to-severe disease.
The company noted that the study also continued to support the therapy’s emerging safety profile, consistent with observations from earlier clinical trials. Additional analyses from ESTUARY and the broader amlitelimab clinical development program are expected to be presented at a future scientific meeting.
Despite its discontinuation of the investigational drug’s development in atopic dermatitis, the company emphasized the substantial unmet need within the eczema treatment space. They pointed to the biologic heterogeneity of atopic dermatitis, pointing to diverse immune pathways contributing to disease development and progression, underscoring the continued need for additional therapeutic approaches for patients whose disease remains inadequately controlled.
Additionally, Sanofi acknowledged the contributions of the patients, caregivers, investigators, and study personnel who took part in the amlitelimab clinical program. They stated it will work alongside investigators, clinical sites, and regulatory authorities to responsibly conclude ongoing atopic dermatitis research. The company also plans to ensure appropriate transition plans for enrolled participants.
The announcement is not expected to impact Sanofi's financial outlook for 2026, with the company confirming its previously issued full-year guidance remains unchanged. While amlitelimab’s development in atopic dermatitis has ended, the drug remains under investigation in other diseases. Sanofi confirmed that its phase 2 clinical trial assessing the medication in celiac disease is continuing, with topline findings slated for the second half of 2026.
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