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

Abstract

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.

Abametapir for the Treatment of Head Lice: A Drug Review

“…Irritation scores from scalp and eye assessments were collected at baseline and day 1, and all other adverse event details were also collected. 12 In all, 100% of the abametapir-treated eggs were unhatched at day 14, versus 64% in the vehicle-treated group. 12 Egg hatch rates of the untreated controls revealed a hatch rate of 93.3% in the abametapir-treated group and 79.5% in the vehicle-treated group, which are consistent with reported hatching rates.…”

“…12 In all, 100% of the abametapir-treated eggs were unhatched at day 14, versus 64% in the vehicle-treated group. 12 Egg hatch rates of the untreated controls revealed a hatch rate of 93.3% in the abametapir-treated group and 79.5% in the vehicle-treated group, which are consistent with reported hatching rates. 12,13 Using a generalized estimating equation model, absolute reduction of hatch rate compared with untreated controls in the abametapir group was calculated at 92.9%, versus 42.3% in the vehicle group, with a difference in hatch rate reduction of 50.6% (P < 0.001; Table 1).…”

“…A double-blind, randomized, vehicle-controlled, parallelgroup phase II study (NCT02097485) assessed clinical ovicidal activity of a single, 10-minute application of abametapir on 50 subjects aged 3 to 17 years old (mean age of 8.5 years) with active head lice infestations. 12 Ovicidal activity was assessed using an ex vivo approach, in which treatment was applied on the patient's head, followed by removal and egg incubation and hatching off the head. Pretreatment eggs were collected from the subjects' heads to serve as controls.…”

“…In abametapir-treated subjects, 88% were lice free at day 7, compared with 32% of the vehicle-treated subjects. 12 The most common treatment-emergent adverse events (TEAEs) were mild rashes in 4 patients (16%), followed by pruritus, pain, and headache, each of which was seen in only 1 patient. All these TEAEs resolved by day 4.…”

Proteases and pseudoproteases in parasitic arthropods of clinical importance

“…Bowles et al discovered the presence of metalloprotease activity in the body louse P. humanus , which is demonstrated to be important for egg hatching [157]. Based on this finding, the group developed a novel drug specifically targeting metalloproteases to control head louse infestation in humans [157,158].…”