Phase 2b randomized clinical trial of amlitelimab, an anti-OX40 ligand antibody, in patients with moderate-to-severe atopic dermatitis.

Background: Amlitelimab, a fully human nondepleting monoclonal antibody targeting OX40 ligand on antigen-presenting cells, could prevent T-cell-driven inflammation seen in atopic dermatitis (AD).

Objective: This trial evaluated the efficacy and safety of amlitelimab in adults with AD.

Methods: In this 2-part, phase 2b, randomized, double-blinded placebo-controlled trial (NCT05131477), patients received subcutaneous amlitelimab every 4 weeks at doses of 250 mg with 500-mg loading dose, 250 mg, 125 mg, or 62.5 mg, or placebo for 24 weeks in Part 1 (1:1:1:1:1 randomization). In Part 2, clinical responders were reallocated 3:1 to withdraw amlitelimab or continue the previous dose regimen for 28 weeks. The primary end point was percent change in Eczema Area and Severity Index (EASI) from baseline to Week 16.

Results: 390 and 190 patients enrolled in Part 1 and Part 2, respectively. Significant percent change decreases in EASI were observed with amlitelimab vs. placebo (P<.001). Clinical responses at Week 24 (Investigator Global Assessment 0/1 and/or EASI-75) were maintained at Week 52 in patients continuing or withdrawn from amlitelimab. In patients maintaining clinical response at Week 52 while off-treatment, >80% had serum amlitelimab concentrations below a 4-μg/mL threshold for several weeks prior to Week 52. Reductions in AD-related biomarkers during Part 1 were maintained through Part 2. Amlitelimab was well tolerated over 52 weeks.

Conclusions: Amlitelimab treatment significantly reduced clinical and biomarker responses, and was well tolerated in adults with AD through Week 52. Sustained responses were observed in the majority of patients after amlitelimab withdrawal for 28 weeks.