Sanofi’s amlitelimab met all primary and key secondary endpoints in the COAST 1 phase 3 study in adults and adolescents with atopic dermatitis

Positive results from the global COAST 1 phase 3 study (clinical study identifier: NCT06130566) showed that amlitelimab, a fully human non-T cell depleting monoclonal antibody that targets OX40-ligand (OX40L), dosed either every four weeks (Q4W) or every 12 weeks (Q12W), met all primary and key secondary endpoints, demonstrating statistically significant and clinically meaningful skin clearance and disease severity compared to placebo at Week 24 in patients aged 12 years and older with moderate-to-severe atopic dermatitis (AD). Amlitelimab was well-tolerated, with no new safety concerns identified in this study.

“These positive first phase 3 results of amlitelimab reinforce the potential of targeting the OX40-ligand to normalize the overactive immune system, without depleting T cells,” said Houman Ashrafian, Executive Vice President, Head of Research & Development at Sanofi. “Amlitelimab may represent a significant advance in the treatment of atopic dermatitis with clinically meaningful and progressively increasing efficacy, with the potential of dosing only four times per year. These promising data seen in a study population that more closely resembles today’s diverse patient landscape, including a substantial proportion previously treated with advanced therapies, support our ambition to deliver a differentiated medicine. We look forward to sharing additional phase 3 results from the OCEANA clinical development program.”

The study’s key secondary endpoints were also achieved across both dosing arms at Week 24, including the proportion of patients who achieved a vIGA-AD 0/1 with only barely perceptible erythema and a reduction from baseline of ≥2-points, and the proportion of patients who achieved a ≥4-point reduction in peak pruritus-numerical rating scale (PP-NRS) from baseline in patients with a baseline PP-NRS ≥4.

The most common treatment emergent adverse events (TEAEs) in COAST 1 (≥5% in any dose arm) were AD, nasopharyngitis and upper respiratory tract infection. All were more common in the placebo arm compared to amlitelimab-treated arms. Injection site reactions were numerically higher in amlitelimab arms (pooled amlitelimab 2.2%, placebo 0.7%). All were mild, patients recovered, and study medication was continued in all cases. Rates of pyrexia (1.1% in pooled amlitelimab arms vs. 0.7% in placebo arm) and chills (0.4% in pooled amlitelimab arms vs. 0% in placebo arm) were low. Overall, rates of treatment-emergent adverse events (TEAEs), serious adverse events, and TEAEs resulting in treatment discontinuation were similar in the placebo arm and pooled amlitelimab arms.

Full results will be submitted for presentation at a forthcoming medical meeting.

The OCEANA clinical development program of amlitelimab in AD, which includes COAST 1 and four other phase 3 studies (SHORE, COAST 2, AQUA, and ESTUARY) is anticipated to read out through 2026 and comprises the foundation for potential global regulatory submissions.

Amlitelimab is currently under clinical investigation, and its safety and efficacy have not been evaluated by any regulatory authority.