The effects of ramelteon in a first-night model of transient insomnia

2.1. Subjects 

Healthy men and women naive to a sleep laboratory environment were eligible to enroll in this study. Subjects were between the ages of 18 and 64 years with a body mass index between 18 and 34 and in overall good health as determined by medical history, physical examination, and clinical laboratory values. All subjects reported a mean sleep latency of less than 30min, a total sleep time between 6.5 and 8h, an Epworth Sleepiness Scale score of less than 10, and a habitual bedtime between 8:30 pm and 12:00 am. Subjects were excluded based on a prior history of insomnia or any recent (within the previous 7 days) changes in sleep schedule. Subjects were instructed to discontinue any medications that may have interfered with the evaluation of the study drug 3 weeks prior to the trial. Caffeine and alcohol use were prohibited within 10h prior to receiving the study drug. The Institutional Review Board at each study site approved the trial, and all subjects gave written informed consent.

2.2. Procedure 

A randomized, multi-center, double-blind, placebo-controlled, single-dose study was conducted using a first-night model of transient insomnia. Subjects checked in to the sleep laboratory 1.5–2h before habitual bedtime and were randomized to receive ramelteon 8mg (FDA-approved dose), ramelteon 16mg, or placebo. Baseline measurements of performance on the Digit Symbol Substitution Test (DSST), Immediate Recall Memory Test, and Visual Analog Scales (VAS) for mood and feelings were recorded. For the DSST, subjects were given a set of symbols and blank boxes with corresponding digits and were asked to complete as many symbol-for-digit substitutions as possible in 90s. The number of correct substitutions made in a 90-s interval was recorded. The Immediate Memory Recall Test involved reading several words to the subject and then having them recall as many as possible. The VAS for mood consisted of 12 items: drowsy, slowed down, sleepy, sedated, tired, worn-out, listless, fatigued, exhausted, sluggish, weary, and bushed. For each mood item, subjects graded their subjective states using a scale of 0 (a little) to 100 (a lot). VAS for feelings involved distinguishing between 8 pairs of 2 opposite extremes (calm/anxious, energetic/fatigued, thinking slowed down/thinking speeded up, peaceful/tense, normal/spacey, at ease/nervous, relaxed/excited, and normal/irritated). Ratings were on a scale from 0 (extreme left condition, i.e., calm) to 100 (extreme right condition, i.e., anxious).

Study medication was administered 30min prior to bedtime, and polysomnography (PSG) recordings were performed continuously for 8h. Upon awakening, subjects completed a post-sleep questionnaire and were evaluated for next-morning residual effects using the DSST, Immediate and Delayed Memory Recall Tests, and VAS for mood and feelings. The Delayed Memory Recall Test involved having the subject recall the words from the Immediate Recall Test administered the night before the PSG recording.

2.3. Efficacy and safety assessments 

Sleep variables were assessed using a single night of PSG recording. The primary variable was latency to persistent sleep (LPS), defined as the elapsed time from the beginning of the PSG recording to the onset of the first 10min of continuous sleep. Secondary variables included objective measures (by PSG) of total sleep time (TST), wake time after sleep onset, and number of awakenings after persistent sleep onset, as well as subjective measures (by post-sleep questionnaire) of sleep latency, total sleep time, wake time after sleep onset, number of awakenings after persistent sleep onset, and overall sleep quality. Sleep architecture was analyzed using PSG recordings of time spent in Stage 1, Stage 2, Stage 3/4 NREM, REM, and latency to REM sleep. Residual next-morning effects were assessed using the tests described previously.

Safety was evaluated using laboratory tests, vital sign monitoring, electrocardiograms, and physical exams. Adverse events (AE) were monitored and recorded throughout the study.

2.4. Statistical analysis 

Statistical analyses were performed in the intent-to-treat population, consisting of all subjects who were randomized and received study medication. Comparisons between the two ramelteon groups and placebo were made with least-squares means and standard error obtained from the analysis of variance (ANOVA) model with effects for treatment and pooled center. Efficacy of ramelteon was assessed using the Fisher protected least significant difference testing procedure to control for Type I error. P-values for pairwise comparisons were obtained using t-tests from the ANOVA model for the overall treatment comparison. Log transformation and non-parametric analyses (using overall ranks) of the primary efficacy variable were performed as confirmatory analyses.

3.1. Population 

A total of 289 subjects (128 men, 161 women, mean age 28.8 years) were randomized and received study medication (98 ramelteon 8mg, 94 ramelteon 16mg, 97 placebo). One woman in the placebo group discontinued the study due to adverse events (agitation and increased sweating). Demographic characteristics for all subjects are shown in Table 1.

Table 1. Demographic and baseline characteristics of the intent-to-treat population

	Characteristic	Placebo	Ramelteon8mg	Ramelteon16mg	Total
	Number of subjects	97	98	94	289
	Mean age (years)	29.8	28.5	28.1	28.8
	Sex – n (%)
	Male	40 (41.2)	43 (43.9)	45 (47.9)	128 (44.3)
	Female	57 (58.8)	55 (56.1)	49 (52.1)	161 (55.7)
	Race – n (%)
	Caucasian	64 (66.0)	60 (61.2)	69 (73.4)	193 (66.8)
	Asian	7 (7.2)	5 (5.1)	2 (2.1)	14 (4.8)
	Black	4 (4.1)	10 (10.2)	4 (4.3)	18 (6.2)
	Hispanic	21 (21.6)	22 (22.4)	19 (20.2)	62 (21.5)
	Other	1 (1.0)	1 (1.0)	0	2 (0.7)
	Mean height (cm)	171.01	169.84	170.20	170.35
	Mean weight (kg)	73.39	71.82	72.33	72.52
	Mean BMI (kg/m2)	24.91	24.88	24.86	24.88

3.2. Efficacy 

Data from both objective and subjective sleep assessments for ramelteon 8mg and 16mg compared with placebo are shown in Table 2. Ramelteon 8mg significantly decreased LPS and significantly increased TST compared with placebo. Ramelteon 16mg also decreased LPS compared with placebo; however, the difference did not reach statistical significance. TST was significantly increased in the ramelteon 16mg group compared with placebo. There were no significant changes in any other objective or subjective measures of sleep. Sleep architecture was not significantly affected by either dose of ramelteon.

Table 2. Objective and subjective efficacy of ramelteon 8mg and 16mg compared to placebo

	Parameter	Placebo	Ramelteon 8mga	Ramelteon 16mga
	LPS (min)
	LS mean (SE)	19.7 (1.87)	12.2 (1.88)	14.8 (1.93)
	P-value		P=0.004	P=0.065
	TST (min)
	LS mean (SE)	419.7 (4.66)	436.8 (4.70)	433.1 (4.82)
	P-value		P=0.009	P=0.043
	Sleep efficiency (%)
	LS mean (SE)	87.9 (0.9)	91.1 (0.91)	90.3 (0.93)
	P-value		P=0.011	P=0.058
	WASO (min)
	LS mean (SE)	38.8 (3.29)	33.8 (3.32)	36.3 (3.40)
	P-value		P=0.283	P=0.592
	NAW (number)
	LS mean (SE)	6.7 (0.47)	7.3 (0.47)	7.2 (0.48)
	P-value		P=0.408	P=0.473
	sSL (min)
	LS mean (SE)	29.5 (3.0)	24.8 (2.98)	27.7 (3.07)
	P-value		P=0.266	P=0.676
	sTST (min)
	LS mean (SE)	411.8 (6.24)	424.2 (6.20)	413.1 (6.40)
	P-value		P=0.154	P=0.883
	sWASO (min)
	LS mean (SE)	36.7 (4.53)	25.6 (4.51)	38.6 (4.64)
	P-value		P=0.081	P=0.771
	sNAW (number)
	LS mean (SE)	3.2 (0.25)	2.8 (0.25)	3.1 (0.25)
	P-value		P=0.239	P=0.785
	Sleep qualityb
	LS mean (SE)	3.4 (0.11)	3.3 (0.11)	3.5 (0.11)
	P-value		P=0.428	P=0.916

a P-values were obtained using t-tests from the ANOVA model. b Scores were based on a 7-point scale: 1=excellent, 7=extremely poor.

3.3. Next-morning residual effects 

Ramelteon 8mg did not significantly alter any measures of next-morning residual effects compared with placebo. No significant differences were detected between ramelteon 16mg and placebo on the DSST, Immediate and Delayed Memory Recall Tests, VAS for feelings, subjective level of alertness, or subjective ability to concentrate. However, a statistically significant increase in VAS for mood was detected between the ramelteon 16mg and placebo groups on measures of drowsiness (30.5 vs. 22.2, P=0.005), slowed down effect (30.8 vs. 22.5, P=0.006), sleepiness (29.1 vs. 20.9, P=0.007), tiredness (27.9 vs. 21.0, P=0.022), and sluggishness (24.4 vs. 18.2, P=0.026).

3.4. Safety 

A total of 31 subjects out of 289 (10.7%) reported at least one AE during the course of the study. The overall incidence rate was 12.4% (12/97) for the placebo group, 13.3% (13/98) for the ramelteon 8mg group, and 6.4% (6/94) for the ramelteon 16mg group. The majority of AEs were mild or moderate in severity. The most commonly reported AE was somnolence (2.1% in the placebo group, 3.1% in the ramelteon 8mg group, and 3.2% in the ramelteon 16mg group), with no other AE reported in more than 3% of subjects in any group. One subject in the ramelteon 8mg group experienced a severe AE consisting of elevated levels of alanine transaminase, aspartate aminotransferase, and lactate dehydrogenase that were considered possibly related to the study drug. One subject in the placebo group discontinued the study early due to agitation and increased sweating which were considered possibly related to the study drug.