Merck Drug May Put Sleep Troubles to Bed

An insomnia drug being developed by Merck & Co was significantly more effective at improving sleep than a placebo in a mid-stage study, according to data presented at the SLEEP 2010 24th Annual Meeting of the Associated Professional Sleep Societies.

Clinical results from a Phase IIb study showed that the drug, MK-4305, improved overall sleep efficiency at night one and at the end of week four in patients with primary insomnia, and was generally well-tolerated. Orexins are neuropeptides that are released by specialized neurons in the hypothalamus region of the brain and are believed to be an important regulator of the brain’s sleep-wake process; MK-4305 works as a dual orexin receptor antagonist.

The drug also demonstrated superiority to placebo in the time it takes to fall asleep and time spent awake after initially falling asleep, according to Merck.

The 254-patient study tested MK-4305 at 10 milligrams, 20 mg, 40 mg, and 80 mg against a placebo. In the one-night measure, patients who took the highest dose of the Merck drug slept 12.2% more of the eight hours than those who got a placebo. The improvement was 11.6% at 40 mg, 6.6% at 20 mg and 6.2% at 10mg.

After four weeks, when there is usually some improvement in the placebo patients, the 80 mg patients slept 7.7% more, while those who received the 40 mg dose slept 7.9% more. At 20 mg, the difference was 10.4% and at 10 mg it was 4.7%.

Phase III trials studying the efficacy and safety of MK-4305 in elderly and non-elderly insomnia patients are ongoing. Merck anticipates filing regulatory applications for MK-4305 in 2012.

“We are encouraged by these phase II results showing positive effects of MK-4305 in patients with primary insomnia,” said David Michelson, M.D., vice president of Neuroscience Clinical Research at Merck. “Phase III research will provide further insight into the safety and efficacy profile of MK-4305, which, if approved, would provide a new class of insomnia treatments.”