392 Safety of amlitelimab in a Phase 2a clinical trial of patients with moderate-to-severe atopic dermatitis

Amlitelimab (SAR445229), a fully human, nondepleting, noncytotoxic, monoclonal antibody, binds to OX40Ligand (OX40L) on antigen-presenting cells to block OX40-OX40L interactions. Outcomes from a 36-week, double-blind, Phase 2a trial (NCT03754309) in patients with moderate-to-severe atopic dermatitis are described. This study aims to assess the safety of OX40-OX40L signaling blockade with amlitelimab in patients with moderate-to-severe atopic dermatitis. Eighty-nine patients were randomized to amlitelimab low-dose (LD; 200-mg loading/100-mg maintenance Q4W), high-dose (HD; 500 mg/250 mg Q4W) or placebo. The coprimary safety endpoint was treatment-emergent adverse event (TEAE) incidence to W16. Safety was assessed to W36. Amlitelimab was well tolerated. Related TEAE incidence was similar between amlitelimab [LD 35% (10/29); HD 20% (6/30)] and placebo [31% (9/29)] to W16 and W36 [LD 10% (2/20); HD 0 (0/22); placebo 0 (0/17)]. The TEAEs more common with amlitelimab vs. placebo (≥5% difference) to W16 included headache [LD 0; HD 3 (10%); placebo 1 (3.4%)], upper respiratory tract infection [3 (10.3%); 0; 1 (3.4%)], hyperhidrosis [0; 2 (6.7%); 0], pyrexia [2 (6.9%); 0; 0], aspartate aminotransferase increased [0; 2 (6.7%); 0] and iron-deficiency anemia [2 (6.9%); 0; 0]; and to W36, Herpes simplex [0; 2 (9.1%); 0]. Before W16, one severe adverse event (SAE) of infected dermal cyst was reported as possibly related; it resolved, and the patient completed the study. Post-W16, one unrelated SAE of sudden death occurred 87 days following the final amlitelimab dose. No hypersensitivity or tolerability events, or clinically meaningful changes in laboratory values, vital signs or electrocardiogram recordings were reported. Amlitelimab was well tolerated in a Phase 2a trial of patients with moderate-to-severe atopic dermatitis, confirming the unremarkable safety profile observed in Phase 1.