Merck Sharp & Dohme has reported that a Phase III clinical trial of Belsomra (suvorexant) C-IV has met the primary and secondary efficacy endpoints for the treatment of insomnia in patients with mild-to-moderate Alzheimer’s disease dementia.

For the primary endpoint, treatment with Belsomra over four weeks led to a mean increase of 73.4 minutes in total sleep time (TST) from baseline, while the figure was 45.2 minutes in the case of placebo.

This represents an improvement of 28.2 minutes with the study drug.

The trial also evaluated the secondary efficacy endpoint of mean wake after persistent sleep onset (WASO) measured in minutes.

The study drug group was observed to demonstrate improvement in WASO compared to placebo.

“We are encouraged by the efficacy and safety results of BELSOMRA in those living with Alzheimer’s disease dementia.”

Merck Research Laboratories Neuroscience Global Clinical Research associate vice-president Dr Joseph Herring said: “Insomnia and other sleep disturbances are more common in people with Alzheimer’s disease dementia, but evidence for the efficacy and safety of sleep medications in this population remains limited.

“We are encouraged by the efficacy and safety results of BELSOMRA in those living with Alzheimer’s disease dementia. Merck plans to file these data with the US Food and Drug Administration for potential inclusion into the Belsomra prescribing information.”

Belsomra is a first-in-class oral, highly selective orexin receptor antagonist. Orexin neurotransmitter is known to be present in the part of the brain that can help keep a person awake.

In the US, the medication has been approved to treat insomnia characterised by difficulties with sleep onset and sleep maintenance.

The randomised, double-blind Phase III trial assessed the safety and efficacy of the drug in participants with mild-to-moderate Alzheimer’s disease dementia and insomnia.

Sleep was measured using overnight polysomnography in a sleep laboratory.

During the study, adverse events were observed in 22.5% of patients on Belsomra compared to 16.1% of participants in the placebo arm. The most common adverse event was somnolence.