A Long Term Safety Study of Suvorexant in Participants With Primary Insomnia (MK-4305-009 AM3)

Cataplexy is defined as a sudden loss of muscle tone while awake which prevents voluntary movement.

Sleep paralysis was defined as the inability to perform voluntary muscle movements during sleep. Sleep paralysis adverse events included sleep-onset paralysis (paralysis as one is falling asleep).

Complex sleep-related behaviors were reported as ECIs and were characterized by patients engaging in specific activities while asleep (e.g., eating, drinking, preparing meals, making phone calls, having sex, driving, and sleep walking).

Falls were adjudicated (to establish whether a fall event was due to cataplexy).

Suicidal ideation included suicidal plans, suicidal tendency, death wishes, life weariness, and suicidal intention. Suicidal behaviors included suicide attempts, suicide gesture, and self-injurious behaviour. Suicidal ideation and/or behavior was reported as an AE and considered an ECI.

Perceptual distortions associated with transitions between wakefulness and sleep were termed as hypnagogic (occurring during the onset of sleep) or hypnopompic (occurring during onset of wakefulness) hallucinations.

The pre-specified terms which were suggestive of abuse potential on this study included depersonalization (feeling of watching oneself act, while having no control over a situation), derealization (alteration in the perception or experience of the external world so that it seems unreal), dissociation (includes a wide array of experiences from mild detachment from immediate surroundings to more severe detachment from physical and emotional experience), euphoric mood (exaggerated feeling of physical and emotional well-being and optimism not consonant with apparent stimuli or events), mania (state of abnormally elevated or irritable mood, arousal, and/or energy levels), hallucination (perception in the absence of a stimulus which has qualities of real perception), and potential study medication misuse.

Withdrawal effects assessed using Tyrer WSQ, which evaluated the presence/absence and severity of withdrawal symptoms with 20 items (i.e. sensitivity to noise, light, smell, touch, feeling unreal, etc). The Tyrer WSQ was completed as part of the evening e-diary prior to dosing on the Month 12 visit and on the 3 consecutive evenings of the DB Run-out Phase (first 3 nights of DB Discontinuation Phase). Responses rated 0 (No), 1 (Yes-moderate), or 2 (Yes-severe); range from 0 (no withdrawal) to 40 (severe withdrawal).

A participant was defined to have a withdrawal symptom if an item during any of the 3 DB Run-out days had emerged for the first time, or had worsened compared to the measurement obtained at the end of the Treatment phase (Month 12). For single night analysis, a patient was defined to have withdrawal effects if the number of withdrawal symptoms (emergent or worsening) was ≥3. For across night analysis, withdrawal was defined as a total of ≥3 symptoms across the 3 nights.

Rebound insomnia was defined as insomnia that occurred following discontinuation of a sedative substance taken to relieve primary insomnia, and was assessed based on subjective total sleep time (sTST) as recorded in the participant's morning e-diary. A strict categorical analysis method (Yes/No) was used in which a participant was considered to have potentially experienced rebound (Yes) if the Morning Diary participant-reported sTST value (in minutes) on any of the 3 nights of the Run-out Phase (first 3 nights of the Discontinuation Phase) occurring after one year of treatment (Month 13) was less than the last value at baseline one year earlier (Month 1).

Rebound insomnia was defined as insomnia that occurred following discontinuation of a sedative substance taken to relieve primary insomnia, and was assessed based on subjective time to sleep onset (sTSO) as recorded in the participant's morning e-diary. A strict categorical analysis method (Yes/No) was used in which a participant was considered to have potentially experienced rebound (Yes) if the Morning Diary participant-reported sTSO value (in minutes) on any of the first 3 nights of the Run-out Phase occurring after one year of treatment (Month 13) was greater than the last value at baseline one year earlier (Month 1).

The sTSTm was defined as the average over time of daily e-diary values for a participant's report of the total amount of time spent asleep before waking for the day (measured in minutes). Weekly sTSTm values (Week 1, Week 2, etc.) were the average of the daily e-diary values for the week. A summary value of this measure for Month 1 was obtained by taking the average of weekly sTSTm values for Weeks 1 through 4; (Week 1 + Week 2 + Week 3 + Week 4) ÷ 4. LS Mean Change from Baseline in sTSTm was then calculated at Week 1, Week 2, Week 3, Week 4, and Month 1.

The sTSOm was defined as the average over time of daily e-diary values for a participant's report of the time he or she required to fall asleep (measured in minutes). Weekly sTSOm values (Week 1, Week 2, etc.) were the average of the daily e-diary values for the week. A summary value of this measure for Month 1 was obtained by taking the average of weekly sTSTm values for Weeks 1 through 4; (Week 1 + Week 2 + Week 3 + Week 4) ÷ 4. LS Mean Change from Baseline in sTSOm was then calculated at Week 1, Week 2, Week 3, Week 4, and Month 1.

Suicidal ideation and/or behavior that occurred on study was also assessed using the C-SSRS, a rater-administered questionnaire used to prospectively assess suicidal ideation and suicidal behavior. C-SSRS assessment was based upon a clinician's interpretation of the participant's responses to the C-SSRS questions, not by a numbered scale.

Suicidal ideation and/or behaviors identified on the C-SSRS may not have been considered an adverse event, based on the investigator's judgment.