SB-649868 is a dual orexin receptor antagonist that was being developed by GlaxoSmithKline as a treatment for insomnia.

[1] A phase I clinical trial evaluated doses up to 80 mg, resulting in significant improvement in sleep latency without adverse effects.

[2] In randomized, double-blind, placebo-controlled crossover trials, the 10 and 30 mg doses increased sleep time and reduced sleep latency.

[3] The subsequent phase II study added a 60 mg dose and observed dose-dependent sleep promotion.

[4] The compound no longer appears to be under active development, with the last study posted to ClinicalTrials.gov completed in 2010.