SEATTLE, WA—Suvorexant (Belsomra; Merck) 20mg/15mg and 40mg/30mg tablets were generally effective and well tolerated by both women and men with insomnia, according to a subgroup analysis of Phase 3 data presented at SLEEP 2015.

Suvorexant, an orexin receptor antagonist, is currently approved to treat insomnia. Prior Phase 3 trial data demonstrated suvorexant was effective and generally well tolerated. A team of scientists from Merck & Co, Inc, Kenilworth, NJ, presented data on the clinical profile of suvorexant in gender subgroups after comparing dose regimens of 40mg/30mg and 20mg/15mg.

The prespecified gender subgroup efficacy analyses included pooled data from two similar, randomized, double-blind, placebo-controlled, parallel-group, three-month trials in elderly and nonelderly patients with insomnia. Based on pharmacokinetics, no differences were expected.

Efficacy assessments were sleep onset and sleep maintenance, measured objectively by polysomnography (PSG) and subjectively by sleep diary. For the objective measure, there were 570 patients (368 female and 202 male) in the placebo arm, 336 in the suvorexant 20mg/15mg arm (216 female and 120 male), and 576 in the suvorexant 40mg/30mg arm (374 female and 202 male). For the subjective measure, there were 740 patients (471 female and 269 male) in the placebo arm, 479 in the suvorexant 20mg/15mg arm (309 female and 170 male), and 752 in the suvorexant 40mg/30mg arm (484 female and 268 male).

“The gender subgroup analyses mirrored the improvements seen with suvorexant 20mg/15mg and 40mg/30mg over placebo in subjective and PSG sleep maintenance and onset endpoints in the primary analyses,” noted W. Joseph Herring, MD, PhD, the study’s lead author.

Researchers found suvorexant was generally well tolerated in women and men. The most frequently reported adverse event was somnolence, “which was generally transient and mild to moderate in intensity,” Dr. Herring noted. “The incidence of somnolence for suvorexant 20mg/15mg was higher in women than in men, but it was comparable between genders for 40mg/30mg,” he added.

The recommended dose suvorexant dose is 10mg, and the maximum approved dose, 20mg; therefore, the 20mg/15mg data “are the most relevant to prescribers in the U.S.,” Dr. Herring concluded.