Merck & Co/MSD has claimed FDA approval for a new use of its insomnia drug Belsomra, treating sleep disruption in people with mild-to-moderate Alzheimer’s disease.
Belsomra (suvorexant) has been approved since 2014 for treating insomnia in the general population characterised by difficulties with falling or staying asleep, becoming the first in a new class of drugs targeting orexin, a brain chemical involved in regulating sleep cycle.
Since then, it’s been joined on the market by Eisai’s recently-approved Dayvigo (lemborexant), which is also being tested in Alzheimer’s-relate sleep disturbances and reported positive results in a phase 2 trial in 2018.
People with Alzheimer’s dementia typically experience poor sleep and disruption of circadian rhythms that lead to night-time activity and daytime sleepiness.
Sleep disturbance is estimated to affect up to 25% of people with mild-to-moderate dementia and 50% of people with severe dementia, with symptoms tending to get worse as dementia progresses in severity.
Belsomra’s activity in Alzheimer’s was demonstrated in a 285-subject, four-week sleep study, published in Alzheimer’s & Dementia, which found significant improvements compared to placebo in total sleep time (TST) and wake after sleep onset (WASO) measures.
Critically, unlike some other insomnia drugs like zolpidem, Belsomra doesn’t seem to lead to a significant increase in confusion and falls in people who are cognitively impaired. The rate of falls in the study at 2% versus 0% in the placebo group, while somnolence the following day was reported in 4.2% and 1.4% of subjects, respectively.
Belsomra is a relatively minor product for Merck, bringing in just $223m in the first nine months of 2019 amid an insomnia drug market that has become dominated by low-cost, generic drugs.
Nevertheless, it accounts for a sizeable chunk of the total insomnia market by value, and is expected to help grow the category from $2.7bn in 2018 to $4.3bn in 2026, according to an Acute Market Research report.
Peak sales of Belsomra are expected to reach around $500m, with the Alzheimer’s indication expected to help the product achieve that increase.