Merck & Co. presents positive data from late-stage studies of insomnia drug suvorexant

Results from two Phase III trials presented Wednesday at the SLEEP meeting showed that Merck & Co.'s suvorexant significantly reduced the time it took patients to fall asleep and helped them stay asleep longer when compared to placebo. The drugmaker noted that based on the studies, which met all but one of their goals, and other data, it will seek FDA approval of the compound later this year.

The three-month studies each included approximately 1000 patients with insomnia not caused by another medical condition. The first trial examined suvorexant dosed at 40 milligrams in patients 18 to 64 years old and at 30 milligrams in those 65 and older, while the second study tested Merck's agent at doses of 30 milligrams in patients aged 18 to 64 years and at 15 milligrams in patients 65 and older.

In the first trial, after three months, suvorexant reduced the time it took to fall asleep by 25.7 minutes and helped patients sleep 60.3 minutes longer than before starting taking the drug. This compared with a time to sleep reduction of 17.3 minutes and 40.6 minutes more sleep for placebo. Further, patients given Merck's compound entered into continuous sleep 36 minutes faster, compared with 26.6 minutes faster in the placebo group. Results also showed that people given suvorexant spent 47.9 minutes less time awake during the night versus 25 minutes less for placebo compared with prior to beginning the study.

In the second study, suvorexant was significantly better than placebo on all measures except for difference in time to fall into continuous sleep at three months, which did not achieve statistical significance. In the trial, Merck's drug reduced the time it took to fall asleep by 33.7 minutes versus 20.5 minutes in the placebo group. Suvorexant helped subjects to sleep an average of 62.8 minutes longer, while placebo led to 37.7 minutes more sleep. In addition, patients who took suvorexant spent 54.2 fewer minutes awake during the night than before they started taking the drug, compared with 24.8 minutes for placebo. According to Merck, suvorexant was also superior to placebo after the first night and after one month of treatment.

Merck noted that the most common side effects associated with suvorexant in the studies were headache and sleepiness, although no serious adverse events were reported. There were also no significant next day residual effects compared with placebo as measured by an assessment of memory, attention, visual scanning and motor speed. Darryle Schoepp, head of neuroscience and ophthalmology for Merck, said that next-day drowsiness occurred in about 10 percent of patients who took suvorexant in the trials, which he noted were similar to results seen in a separate one-year safety study.

Schoepp remarked that suvorexant appears to be well suited for patients who are not getting a full night sleep from existing drugs, including the long-acting version of Sanofi's Ambien (zolpidem). "Ambien CR only keeps you asleep five to six hours," he said, adding that "we've shown our drug keeps you asleep the last third of the night as well."

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