W Joseph Herring, MD, PhDW Joseph Herring, MD, PhD
The FDA has approved an expanded indication for suvorexant (Belsomra; Merck) for the treatment of insomnia in patients with mild to moderate Alzheimer disease (AD).

“We’re pleased that the prescribing information for Belsomra now includes findings from Merck’s first dedicated study of an insomnia medication in patients with mild to moderate Alzheimer’s disease,” W. Joseph Herring, MD, PhD, associate vice president, Global Clinical Research, Neuroscience, Merck Research Laboratories, said in a statement.1

Suvorexant, an oral orexin receptor antagonist, was previously approvedfor the treatment of insomnia characterized by difficulties with sleep onset and/ or sleep maintenance.

The update stems from results from a randomized, double-blind, placebo-controlled, parallel-group, 4-week polysomnography trial that evaluated the safety and efficacy of suvorexant in patients with mild to moderate AD.2 A total of 285 patients were randomly assigned 1:1 to either 10 mg of suvorexant or placebo. Among the 142 patients who received suvorexant, 77% received an increased dose of 20 mg suvorexant for approximately 14 additional days.

Compared to those treated with placebo, patients taking suvorexant demonstrated a statically significant improvement in both total sleep time (TST) and wake after sleep onset outcomes. From baseline, patients who received suvorexant had a mean improvement in TST from baseline of 73 minutes compared to 45 minutes in the placebo group (difference, 28 minutes; 95% CI, 11-45, P <.01). From baseline to the end of week 4, the mean TST in patients who received suvorexant increased from 277.7 minutes to 349.4 minutes.

Somnolence (4% compared to 1% for placebo), dry mouth (2% compared to 1% for placebo), and falls (2% compared to 0% for placebo) were among the adverse reactions that were documented in >2% of patients and greater than placebo. One patient from each group discontinued the trial for an ankle fracture and diarrhea. 

Suvorexant should not be taken when operating a vehicle. The drug may increase the risk of falling asleep while driving, as well as impair daytime wakefulness. Those who take suvorexant are at risk for sleep paralysis, hypnagogic/hypnopompic hallucinations, and cataplexy-like symptoms.

Central nervous system depression can last for up to several days following discontinuation of suvorexant. Patients should be reevaluated if insomnia continues after 7 to 10 days of treatment.
REFERENCES:
1. Merck receives approval for belsomra (suvorexant) C-IV label update to include findings from study of insomnia in patients with mild-to-moderate Alzheimer’s disease [news release]. Kenilworth, NJ: Merck. February 3, 2020. mrknewsroom.com/news-release/prescription-medicine-news/merck-receives-approval-belsomra-suvorexant-c-iv-label-updat. Accessed February 4, 2020.
2. Herring JW, Ceesay P, Snyder E, et al. Polysomnographic assessment of suvorexant in patients with probable Alzheimer’s disease dementia and insomnia: a randomized trial. J Alzheimers Parkinsonsim Dement. Published online January 15, 2020. doi:10.1002/alz.12035.