FDA rejects Merck insomnia drug, seeks lower-dose version

(Reuters) - U.S. health regulators have rejected Merck & Co's new insomnia drug application but opened the door to approving a lower-dose version of the medication, the company said on Monday.

Merck said it received a complete response letter from the U.S. Food and Drug Administration saying that the agency could consider a 10 milligram starting dose of suvorexant for most patients, but that the company would have to have that dosage ready before it could be approved.

Merck had proposed that elderly patients start by taking 15 milligrams of the drug and increase that to 30 if necessary, and had recommended that non-elderly adults start on 20 milligrams and increase to 40 milligrams if needed. In its letter, the FDA determined that doses of 30 mg and 40 mg were not safe for approval, Merck said on Monday.

Merck said it doesn't see the need for further clinical studies to move forward with a 10 mg dose, but would require manufacturing studies to move ahead.

(Reporting by Michele Gershberg; Editing by Gerald E. McCormick)