of side effects in patients taking zolpidem and other members of the GABA class. Some patients reported that they raided their refrigerators in the middle of the night and woke up with no memory of having eaten everything in sight. Others went on driving expeditions in the wee hours, again with complete amnesia for those events the next day. That’s why advertisements for prescription sleep drugs now include a laundry list of warnings about potential brain-altering side effects.
In addition to tracking some patients for up to a year, Merck studied several different doses of suvorexant. The company also collected separate datasets for elderly patients, who face a higher risk of suffering life-threatening falls and other complications if sleeping pills leave them with next-day hangovers. Merck measured safety and efficacy by asking patients to keep diaries of their sleep patterns and side effects, and by sending some of the trial participants to sleep labs, where they were hooked up to sensors that recorded every reaction to the experimental compound. “We looked at all these different things, and we really saw no [safety] signals,” Schoepp says.
So where did suvorexant underperform during the two trials presented today? In one of the trials, patients taking suvorexant did not fall asleep all that much faster than those taking placebo. Schoepp suspects some of the patients in the control group might have experienced the infamous “placebo effect”—meaning the mere thought they may be getting some help with their insomnia woes was enough to put them to sleep.
Still, Schoepp contends, the one disappointment shouldn’t cast too much of a shadow on the entire study program. “You have to put that one data point in context,” he says. During the trials, Merck measured five aspects of both falling asleep and staying asleep, and it did so over three different time periods. “That’s 15 things we looked at, multipled by two trials. So we had 30 endpoints across all the trials and we met 29 of them. If you look at the overall package, it’s quite effective.”
During the meeting in Boston, Merck will also discuss data from the other trials of suvorexant, including results from a study in which the company monitored the ability of elderly patients to drive the day after taking the drug. The company plans to present additional results from its pivotal trials later this year. All the trials are now complete, Schoepp says, and the company is preparing the package it will submit to the FDA for approval.
Merck is also studying the potential of a compound that’s similar to suvorexant in treating conditions that are related to insomnia. For example, it is researching the drug for preventing migraine headaches, treating neuropathic pain, and enhancing the activity of anti-depressants.
Schoepp, a trained pharmacist, brings an interesting perspective to the neurology market, having started his career in the 1970s as a pharmacy intern. “Back then we didn’t know how the early [insomnia] drugs worked. Later we found out they worked through GABA,” he says. “As time has gone on, we’ve developed newer GABA agents, but essentially the mechanism hasn’t changed.” Suvorexant, on the other hand, was not an accidental discovery, but rather a deliberate effort by Merck’s scientists to exploit a growing understanding of orexin biology. “This is really a targeted mechanism for sleep,” he says. “That’s a rare event in neuroscience.”
