Conditions: Primary Insomnia
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 1023
Healthy volunteers: no

Brief summary:
This is a multicenter study to test the hypothesis that suvorexant (MK-4305) is superior to placebo in improving insomnia as measured by change from baseline in: subjective total sleep time and time to sleep onset, wake time after persistent sleep onset, and latency to onset of persistent sleep. Participants who complete the initial 3-month Treatment (TRT) Phase may participate in an optional 3-month Extension (EXT) Phase.

Detailed description:

Arms:
arm 1: Drug arm 2: Drug arm 3: Placebo Comparator

Interventions: intervention 1: Suvorexant High Dose (HD) intervention 2: Suvorexant Low Dose (LD) intervention 3: Comparator: Placebo
Intervention descriptions: intervention 1: Suvorexant 40 mg + placebo matching suvorexant 20 mg for participants \<65 years old; Suvorexant 30 mg + placebo matching suvorexant 15 mg for participants ≥65 years old; all study drug is tablet for oral administration, taken once daily at bedtime. Participants receive this dose during the 3-month TRT Phase and, if applicable, the optional 3-month EXT Phase. During the 1-week double-blind (DB) Run-out (RO) following the TRT/EXT phase, participants in this study arm receive the noted suvorexant dose or placebo, in a 1:1 ratio. During the 2-week single-blind Run-in period prior to randomization all participants receive placebo to suvorexant once daily at bedtime. intervention 2: Suvorexant 20 mg + placebo matching suvorexant 40 mg for participants \<65 years old; Suvorexant 15 mg + placebo matching suvorexant 30 mg for participants ≥65 years old; all study drug is tablet for oral administration, taken once daily at bedtime. Participants receive this dose during the 3-month TRT Phase and, if applicable, the optional 3-month EXT Phase. During the 1-week DB RO following the TRT/EXT phase, participants in this study arm receive the noted suvorexant dose or placebo, in a 1:1 ratio. During the 2-week single-blind Run-in period prior to randomization all participants receive placebo to suvorexant once daily at bedtime. intervention 3: Matching placebos to suvorexant 40 mg and 20 mg for participants \<65 years old; matching placebos to suvorexant 30 mg and 15 mg for participants ≥65 years old; all study drug is tablet for oral administration, taken once daily at bedtime. Placebo is a third treatment arm for comparison to the two active (suvorexant) treatment arms during the 3-month TRT Phase and, if applicable, the optional 3-month EXT Phase. During the 1-week DB RO following the TRT/EXT phase, participants in this study arm continue to receive placebo. During the 2-week single-blind Run-in period prior to randomization all participants receive placebo to suvorexant once daily at bedtime.

Protocol document: