Conditions: Primary Insomnia
Allocation: RANDOMIZED | Intervention model: CROSSOVER
Enrollment: 254
Healthy volunteers: no

Brief summary:
A cross-over, polysomnography study to test the safety, tolerability and effectiveness of different doses of suvorexant (MK-4305) in the treatment of patients with primary insomnia.

Detailed description:

Arms:
arm 1: After an \~1- to 2-week single-blind placebo run-in period, participants received 10 mg suvorexant daily prior to bedtime for 4 weeks during Treatment Period 1, followed by a 1-week single-blind placebo washout period, followed by dose-matched placebo to suvorexant daily prior to bedtime during Treatment Period 2. arm 2: After an \~1- to 2-week single-blind placebo run-in period, participants received dose-matched placebo to suvorexant daily prior to bedtime for 4 weeks during Treatment Period 1, followed by a 1-week single-blind placebo washout period, followed by 10 mg suvorexant daily prior to bedtime during Treatment Period 2. arm 3: After an \~1- to 2-week single-blind placebo run-in period, participants received 20 mg suvorexant daily prior to bedtime for 4 weeks during Treatment Period 1, followed by a 1-week single-blind placebo washout period, followed by dose-matched placebo to suvorexant daily prior to bedtime during Treatment Period 2. arm 4: After an \~1- to 2-week single-blind placebo run-in period, participants received dose-matched placebo to suvorexant daily prior to bedtime for 4 weeks during Treatment Period 1, followed by a 1-week single-blind placebo washout period, followed by 20 mg suvorexant daily prior to bedtime during Treatment Period 2. arm 5: After an \~1- to 2-week single-blind placebo run-in period, participants received 40 mg suvorexant daily prior to bedtime for 4 weeks during Treatment Period 1, followed by a 1-week single-blind placebo washout period, followed by dose-matched placebo to suvorexant daily prior to bedtime during Treatment Period 2. arm 6: After an \~1- to 2-week single-blind placebo run-in period, participants received dose-matched placebo to suvorexant daily prior to bedtime for 4 weeks during Treatment Period 1, followed by a 1-week single-blind placebo washout period, followed by 40 mg suvorexant daily prior to bedtime during Treatment Period 2. arm 7: After an \~1- to 2-week single-blind placebo run-in period, participants received 80 mg suvorexant daily prior to bedtime for 4 weeks during Treatment Period 1, followed by a 1-week single-blind placebo washout period, followed by dose-matched placebo to suvorexant daily prior to bedtime during Treatment Period 2. arm 8: After an \~1- to 2-week single-blind placebo run-in period, participants received dose-matched placebo to suvorexant daily prior to bedtime for 4 weeks during Treatment Period 1, followed by a 1-week single-blind placebo washout period, followed by 80 mg suvorexant daily prior to bedtime during Treatment Period 2.

Interventions: intervention 1: Suvorexant intervention 2: Dose-matched Placebo to Suvorexant
Intervention descriptions: intervention 1: oral tablet taken before bedtime intervention 2: Dose-matched placebo to suvorexant taken before bedtime (oral tablet)

Protocol document: