Merck: suvorexant on track to refresh insomnia market.
Merck: suvorexant on track to refresh insomnia market
Merck & Co. has announced positive Phase III data for its insomnia candidate suvorexant, renewing hope in the novel orexin receptor antagonist drug class after speculation about class-wide safety issues. Although suvorexant has the potential to address key unmet needs in the treatment of insomnia, demonstration of superiority over zolpidem and lack of scheduling will be key to commercial success.
Results from the Phase III study found that patients who had been taking suvorexant for 12 months and were immediately switched to placebo did not experience clinically meaningful withdrawal symptoms and rebound insomnia did not emerge. Although safety and tolerability formed the study’s primary endpoints, secondary efficacy measures found that patients treated with suvorexant fell asleep significantly faster, stayed asleep significantly longer, and spent significantly less time awake during the night compared to patients who received placebo.
Presentation of the full results builds on Merck’s November 2011 announcement of suvorexant’s “excellent efficacy” in a long-term Phase III trial, as well as positive Phase IIb data released in June 2010.
Assurance of suvorexant’s long-term safety is a boon to Merck after “safety observations” preceding the January 2011 discontinuation of Actelion/GlaxoSmithKline’s late-stage orexin candidate, almorexant, fueled speculation that the safety concerns may be a class-wide issue. Moreover, that suvorexant’s data are derived from one of the longest, continuously dosed, placebo-controlled trials of a sleep medication ever conducted will likely foster confidence among prescribers.
However, it is important to note that to date Merck has made no mention as to whether suvorexant is associated with tolerance or dependence, although the company anticipates that the drug will be evaluated by the Controlled Substance Staff of the FDA. With leading therapies in the insomnia market, including Sanofi’s Ambien CR (zolpidem controlled release), designated as Schedule IV controlled substances, a lack of scheduling would serve as an important product differentiator for suvorexant.
Merck remains on track to file a New Drug Application (NDA) for suvorexant with the FDA in 2012. Datamonitor anticipates US launch of the product to take place in Q4 2013, making it the first-to-market orexin drug. It is expected that availability of suvorexant will serve to address three key unmet needs in the management of insomnia: the need for treatments that confer a superior tolerability profile than those of currently marketed hypnotics; the need for more effective insomnia treatments in the elderly population; and the need for treatments that are able to improve sleep maintenance. Suvorexant’s ability to address these unmet needs will ensure a strong uptake after launch. The drug’s novel mechanism of action and Merck’s sales and marketing muscle also bode well for the drug’s commercial success.
However, in order to guarantee pole position in the insomnia market, Merck would be well served to demonstrate comparable or superior efficacy with suvorexant in terms of sleep onset and maintenance over the current gold-standard treatment, zolpidem, as well as a lack of potential for tolerance and addiction.