Novel method of treatment offers fewer side effects
Merck & Co has moved a step closer to bringing its novel insomnia drug suvorexant to market after reporting positive data in a phase III trial.
The company is now on track to file for approval of suvorexant before the end of the year, with a chance of bringing to market the first drug for insomnia treatment that does not work by enhancing the activity of the neurotransmitter GABA.
Suvorexant acts as an antagonist of orexin, a hormone that seems causes wakefulness, and is thought to avoid many of the side effects of current insomnia drugs such as next-day drowsiness, sleep walking, and dependency.
The latest data come from a 12-month, placebo-controlled study of suvorexant that was designed to assess safety and long-term efficacy.
Earlier studies have already supported its short-term efficacy, and Merck wanted to show that these benefits were maintained, and also to demonstrate that suvorexant was free of safety concerns that led to the discontinuation of GlaxoSmithKline (GSK) and Actelion's rival orexin antagonist almorexant.
The results showed that patients who had been taking suvorexant for 12 months and were switched to placebo saw their insomnia return, but clinically meaningful withdrawal symptoms and rebound insomnia did not emerge.
"What happens when patients stop taking a sleep medication is a key concern for both patients and healthcare professionals," said study investigator James Walsh of Stanford University School of Medicine.
Insomnia drugs represent a multibillion dollar market worldwide, but the sector has been eroded in recent years by the launch of generic versions of one of the big GABA-modulating drugs - zolpidem - and will experience another shift when Eisai's Lunesta (eszopiclone) starts to lose patent protection later this year.
If approved with a claim for greater tolerability, suvorexant could be a major new product for Merck with sales in excess of $1bn.
Suvorexant is one of five new drugs the company hopes to bring to market or file 2012 and 2013, along with vorapaxar, an experimental drug for acute coronary syndrome chest pain caused by coronary artery disease), HPV vaccine V503, osteoporosis treatment odanacatib and atherosclerosis medicine Tredaptive ER.