Merck has a lot riding on its new drug application for the sleep drug Suvorexant. Billed by some--though certainly not all--analysts as a likely blockbuster, the pharma giant ($MRK) has been enthusiastic about spreading word of the drug's positive late-stage data from a pair of Phase III studies. And now researchers are back talking up a new animal study that purports to do what Phase III never did--compare it to popular generic drugs that now dominate a shrinking market.
Company researchers told Reuters that studies involving rats and monkeys could help show that Suvorexant was less likely to interfere with a person's memory or attention. For rhesus monkeys, they said, the generic GABA inhibitor they were given made them less capable of responding quickly to a flashing green light, as they had been taught, compared to the primates given an orexin inhibitor--Suvorexant's claim to fame. For rats, there were signs that they were less likely to recall an object.
Significantly, the GABA inhibitors--Lunesta and Ambien--are known to work on various regions of the brain, which have contributed to the kind of cognition issues that the researchers were targeting in the study. "When you hit those, you don't just hit the sleep system," John Renger, executive director and head of neuroscience basic research at Merck, tells Reuters.
Suvorexant blocks orexins, which help keep the body alert. The theory is that targeting this new mechanism will give insomniacs--a whopping 10% of the American population--a better shot at a good night's sleep with fewer safety issues.
The FDA is likely to approve Suvorexant later this year, probably as a controlled substance. The drug spurred no signs of a serious adverse effect in the lengthy Phase III program and bested placebos in all but one primary endpoint on getting patients to sleep. The problem for Merck, and one that this animal study will do little or nothing to solve, is that if it is approved, Suvorexant will certainly be compared by payers to generic drugs available for only a fraction of the cost.
Last fall Datamonitor noted that "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 [Ambien], as well as a lack of potential for tolerance and addiction."
Given the widespread popularity of these drugs, unreliable animal data is unlikely to change anyone's mind about which therapies should be covered. That would require a human head-to-head study, which would involve a bold gamble on Merck's part.
- here's the story from Reuters