The US FDA rejects approval of Merck’s insomnia drug

The US Food and Drug Administration have rejected Merck & Co's experimental insomnia drug for approval, citing safety issues.

Merck had evaluated the efficacy of the insomnia drug at doses of 10mg to 40mg, however the FDA's Complete Response Letter to Merck advised that the 10mg dose of suvorexant should be the starting dose for most patients and therefore must be available before the drug can be approved.

The FDA also advised a 5mg dose would be necessary for patients taking concomitant moderate CYP3A4 inhibitors.

"We will evaluate the requests outlined in the Complete Response Letter, and expect thereafter to work expeditiously with the FDA to make suvorexant available as a new treatment option for patients suffering from insomnia."

Roger M. Perlmutter, M.D., Ph.D., president, Merck Research Laboratories.

Both FDA approval and also a separate scheduling determination by the US Drug Enforcement Administration are required before Merck can introduce suvorexant into the US.

If approved, suvorexant would be the first in a new class of medicines, called orexin receptor antagonists, for use in patients with insomnia. Insomnia is a condition where patients find it difficult to fall asleep and / or stay asleep. Today, insomnia affects up to a third of adults and there is a clear need for additional treatment options.