Arena Pharmaceuticals has reported Phase I clinical trial results of APD916, a novel drug for the treatment of narcolepsy with cataplexy.

The double-blind, randomised and placebo-controlled trial was designed to evaluate the safety, tolerability and pharmacokinetics of 1mg, 3mg and 5mg single doses of APD916, which targets the histamine H3 receptor.

The trial enrolled 24 healthy volunteers, who were grouped into three treatment arms of eight participants each. It each arm, six were randomised to receive APD916 and two to placebo.

The study results showed that APD916 exhibited dose-proportional pharmacokinetic exposure over the tested dose range, and the terminal half life was approximately 50 hours.

Dose-limiting CNS adverse events such as abnormal dreams, insomnia and nightmare were reported at the 5mg dose, and insomnia occurred at the 1mg dose.

Adverse events such as nausea, insomnia, parosmia, headache, alterations in perception of body temperature, abnormal dreams and visual and tactile hallucinations were commonly reported with 3mg and 5mg doses.

All the adverse events reported during the trial were mild or moderate in nature, and no serious adverse events were reported.