Merck receives Complete Response Letter for Suvorexant, Merck’s investigational medicine for insomnia

Merck (NYSE: MRK), known as MSD outside the United States and Canada, announced today that the company has received a Complete Response Letter from the U.S. Food and Drug Administration (FDA) regarding the New Drug Application for suvorexant, Merck’s investigational medicine for the treatment of insomnia.

In the Complete Response Letter, the FDA advised Merck that:

• the efficacy of suvorexant has been established at doses of 10 mg to 40 mg in elderly and non-elderly adult patients;
• 10 mg should be the starting dose for most patients, and must be available before suvorexant can be approved;
• 15 mg and 20 mg doses would be appropriate in patients in whom the 10 mg dose is well-tolerated but not effective; and,
• for patients taking concomitant moderate CYP3A4 inhibitors, a 5 mg dose would be necessary.

In addition, the FDA determined that the safety data do not support the approval of suvorexant 30 mg and 40 mg.

“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,” said Roger M. Perlmutter, M.D., Ph.D., president, Merck Research Laboratories.

Based on initial review of the letter, Merck has determined that additional clinical studies of suvorexant 10 mg will not be necessary. However, manufacturing studies will be required to advance the 10 mg dosage form. Merck will discuss with the FDA whether additional studies will be required to support the 5 mg dose.

As previously disclosed, both FDA approval and a separate scheduling determination by the U.S. Drug Enforcement Administration are required before Merck can introduce suvorexant in the United States.

Insomnia is a condition characterized by difficulty falling asleep and/or staying asleep. Today, insomnia affects up to a third of adults and there is a clear need for additional treatment options.

If approved, suvorexant would be the first in a new class of medicines, called orexin receptor antagonists, for use in patients with insomnia. Suvorexant’s novel mechanism is distinct from current treatments. Merck researchers developed suvorexant to facilitate sleep by blocking the action of orexins, which are neurotransmitters in the brain that help to keep a person awake.