Sanofi's $1.4B Bet Pays Off with Promising Phase II Eczema Data

Pictured: Atopic dermatitis patient scratches their arm/iStock

Pictured: Atopic dermatitis patient scratches their arm/iStock

The company announced Tuesday that topline data from the Phase IIb STREAM-AD trial showed that Sanofi’s investigational antibody amlitelimab met the study’s primary outcome and strongly eased symptoms in patients with moderate-to-severe atopic dermatitis.

After 16 weeks of treatment, patients in the amlitelimab group saw significant improvements in their average Eczema Area and Severity Index (EASI) scores compared to placebo. Amlitelimab retained its statistical edge over the placebo across all four studied doses.

Sanofi’s candidate also cleared the study’s key secondary endpoints, including biomarker measurements, which suggested that amlitelimab had therapeutic effects on both type 2 and non-type 2 inflammatory pathways, according to the company’s news release. Improvements in primary and secondary measures persisted through 24 weeks of follow-up.

These Phase IIb results support amlitelimab’s mechanism of action and indicate that “targeting OX40-Ligand has the potential to provide a first and best-in-class treatment option that addresses type 2 and non-type 2 inflammation” in atopic dermatitis (AD) and other inflammatory conditions, Naimish Patel, Sanofi’s head of global development for immunology and inflammation, said in a statement.

Sanofi did not provide specific and detailed data in Tuesday’s announcement but promised to do so at a future scientific conference.

Amlitelimab is a fully human monoclonal antibody designed to target the OX40-Ligand, a cell surface protein that, along with its corresponding receptor OX40, plays a crucial role in the modulation of the inflammatory process.

By targeting the OX40-Ligand, amlitelimab could help restore the balance between pro-inflammatory and regulatory immune cells. Amlitelimab may potentially be the first medicine that treats AD via an OX40-Ligand-based mechanism.

Sanofi won rights to amlitelimab in January 2021 when it bought U.K.-based biotech Kymab for $1.1 billion upfront and the promise of up to $350 million in milestones. At the time, Sanofi CEO Paul Hudson said that amlitelimab’s novel mechanism of action “may provide treatment for patients with suboptimal responses to available therapies.”

Also attempting to usher an OX40-Ligand-targeted therapy to the market is Amgen and its Japanese collaborator Kyowa Kirin, whose candidate rocatinlimab has recently cleared Phase IIb assessments for AD, and for which a Phase III study dubbed ROCKET is currently enrolling.

In December 2022, the pharma partners published mid-stage data for rocatinlimab in The Lancet, showing that the investigational antibody significantly improved EASI scores after 16 weeks of treatment relative to placebo. Rocatinlimab also cleared the study’s secondary endpoints and showed a favorable safety profile.

Rocatinlimab was discovered and initially developed by Kyowa Kirin. Amgen gained access to the candidate in a June 2021 development and commercialization agreement valued at $400 million upfront, with a potential $850 million in milestones and royalties.

Tristan Manalac is an independent science writer based in metro Manila, Philippines. He can be reached at or

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