Effect of a New Head Lice Treatment, Abametapir Lotion, 0.74%, on Louse Eggs: A Randomized, Double-Blind Study

Few head lice treatments have demonstrated effectiveness against louse eggs. Abametapir, a metalloproteinase inhibitor, is able to target metalloproteinases critical to egg hatching and louse development. In this double-blind, phase 2 study, 50 subjects aged ≥3 years with active head lice infestation were randomized to receive a single treatment of abametapir lotion, 0.74%, or vehicle (control), applied to scalp and hair for 10 minutes. Ovicidal efficacy was measured by recording the hatch rate of eggs collected from each subject’s hair before and after treatment and incubated for 14 days. With abametapir, 100% of treated eggs remained unhatched compared with 64.0% for vehicle. Accounting for pretreatment hatch rates, the absolute reduction in egg hatching was 92.9% for abametapir versus 42.3% for vehicle ( P < .0001). The most frequently reported adverse event was rash (16%). Abametapir lotion, 0.74%, demonstrated significant ovicidal activity against head lice eggs with a single application.