Idorsia announced positive topline results from a phase 3 study of daridorexant, an investigational dual orexin receptor antagonist, for the treatment of insomnia.

The multicenter, double-blind, placebo-controlled study evaluated the efficacy and safety of daridorexant in 930 patients (39.1% ≥65 years of age) with insomnia. Patients were randomized to receive daridorexant 25mg, 50mg or placebo orally once in the evening  for 3 months. The co-primary end points were the change from baseline to months 1 and 3 in sleep onset, as measured by a decrease in latency to persistent sleep, and sleep maintenance, as measured by a decrease in wake time after sleep onset. A key secondary end point was subjective total sleep time (sTST), measured daily with a patient diary at home.

Results showed that daridorexant 25mg and 50mg significantly improved sleep onset and sleep maintenance at months 1 and 3 compared with placebo, which was assessed objectively in a sleep lab by polysomnography. Additionally, both doses of daridorexant significantly increased sTST from baseline. Patients treated with daridorexant 50mg also demonstrated a significant improvement in daytime performance at months 1 and 3.

The safety profile of daridorexant was found to be comparable to placebo. The most frequent treatment-emergent adverse events (≥3% higher than placebo) reported were nasopharyngitis and headache. Moreover, daridorexant was not associated with next morning residual effects, rebound insomnia, or withdrawal symptoms upon discontinuation.

Detailed study results will be made available through scientific disclosure at upcoming congresses and in peer reviewed publications. Results from a second phase 3 study evaluating the 10mg and 25mg doses are expected in the third quarter of 2020.

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