Ramelteon 8 mg Tablet, Film Coated, 30-count — NDC 72189-369-30 (Billing 72189-0369-30)

12.1Mechanism of Action Ramelteon is a melatonin receptor agonist with both high affinity for melatonin MT 1 and MT 2 receptors and relative selectivity over the MT 3 receptor. The activity of ramelteon at the MT 1 and MT 2 receptors is believed to contribute to its sleep-promoting properties, as these receptors, acted upon by endogenous melatonin, are thought to be involved in the maintenance of the circadian rhythm underlying the normal sleep-wake cycle. Ramelteon has no appreciable affinity for the GABA receptor complex or for receptors that bind neuropeptides, cytokines, serotonin, dopamine, noradrenaline, acetylcholine, and opiates.

Ramelteon also does not interfere with the activity of a number of selected enzymes in a standard panel. The major metabolite of ramelteon, M-II, is pharmacologically active and has approximately one tenth and one fifth the binding affinity of the parent molecule for the human MT 1 and MT 2 receptors, respectively. However, M-II circulates at higher concentrations than the parent producing 20- to 100-fold greater mean systemic exposure when compared to ramelteon.

Similar to ramelteon, M-II does not interfere with the activity of a number of endogenous enzymes. All other known metabolites of ramelteon are inactive.

12.3Pharmacokinetics The pharmacokinetic profile of Ramelteon Tablets has been evaluated in healthy subjects as well as in subjects with hepatic or renal impairment. When administered orally to humans in doses ranging from 4 to 64 mg, ramelteon undergoes rapid, high first-pass metabolism, and exhibits linear pharmacokinetics. Maximal serum concentration (C max) and area under the concentration-time curve (AUC) data show substantial intersubject variability, consistent with the high first-pass effect; the coefficient of variation for these values is approximately 100%.

Several metabolites have been identified in human serum and urine. Absorption Ramelteon is absorbed rapidly, with median peak concentrations occurring at approximately 0.75 hour (range, 0.5 to 1.5 hours) after fasted oral administration. Although the total absorption of ramelteon is at least 84%, the absolute oral bioavailability is only 1.8% due to extensive first-pass metabolism.

Distribution In vitro protein binding of ramelteon is approximately 82% in human serum, independent of concentration. Binding to albumin accounts for most of that binding, since 70% of the drug is bound in human serum albumin. Ramelteon is not distributed selectively to red blood cells.

Ramelteon has a mean volume of distribution after intravenous administration of

73.6L, suggesting substantial tissue distribution. Metabolism Metabolism of ramelteon consists primarily of oxidation to hydroxyl and carbonyl derivatives, with secondary metabolism producing glucuronide conjugates. CYP1A2 is the major isozyme involved in the hepatic metabolism of ramelteon; the CYP2C subfamily and CYP3A4 isozymes are also involved to a minor degree.

The rank order of the principal metabolites by prevalence in human serum is M-II, M-IV, M-I, and M-III. These metabolites are formed rapidly and exhibit a monophasic decline and rapid elimination. The overall mean systemic exposure of M-II is approximately 20- to 100-fold higher than parent drug.

Elimination Following oral administration of radiolabeled ramelteon, 84% of total radioactivity was excreted in urine and approximately 4% in feces, resulting in a mean recovery of 88%. Less than 0.1% of the dose was excreted in urine and feces as the parent compound. Elimination was essentially complete by 96 hours postdose.

Repeated once daily dosing with Ramelteon Tablets does not result in significant accumulation owing to the short elimination half-life of ramelteon (on average, approximately one to 2.6 hours). The half-life of M-II is two to five hours and independent of dose. Serum concentrations of the parent drug and its metabolites in humans are at or below the lower limits of quantitation within 24 hours.

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14.1Controlled Clinical Trials Chronic Insomnia Three randomized, double-blind trials in subjects with chronic insomnia employing polysomnography (PSG) were provided as objective support of Ramelteon's effectiveness in sleep initiation. One study enrolled younger adults (aged 18 to 64 years, inclusive) with chronic insomnia and employed a parallel design in which the subjects received a single, nightly dose of Ramelteon Tablets (8 or 16 mg) or matching placebo for 35 days. PSG was performed on the first two nights in each of Weeks 1, 3, and 5 of treatment.

Ramelteon Tablets reduced the average latency to persistent sleep at each of the time points when compared to placebo. The 16 mg dose conferred no additional benefit for sleep initiation. The second study employing PSG was a three-period crossover trial performed in subjects aged 65 years and older with a history of chronic insomnia.

Subjects received Ramelteon Tablets (4 or 8 mg) or placebo and underwent PSG assessment in a sleep laboratory for two consecutive nights in each of the three study periods. Both doses of Ramelteon Tablets reduced latency to persistent sleep when compared to placebo. The third study evaluated long term efficacy and safety in adults with chronic insomnia.

Subjects received a single, nightly dose of Ramelteon Tablets 8 mg or matching placebo for six months. PSG was performed on the first two nights of Week 1 and Months 1, 3, 5, and 6. Ramelteon Tablets reduced sleep latency at each time point when compared to placebo.

In this study, when the PSG results from nights 1 and 2 of Month 7 were compared to the results from nights 22 and 23 of Month 6, there was a statistically significant increase in LPS of 33% (9.5 minutes) in the ramelteon group. There was no increase in LPS in the placebo group when the same time periods were compared. A randomized, double-blind, parallel group study was conducted in outpatients aged 65 years and older with chronic insomnia and employed subjective measures of efficacy (sleep diaries).

Subjects received Ramelteon Tablets (4 or 8 mg) or placebo for 35 nights. Ramelteon Tablets reduced patient-reported sleep latency compared to placebo. A similarly designed study performed in younger adults (aged 18 to 64 years) using 8 and 16 mg of ramelteon did not replicate this finding of reduced patient-reported sleep latency compared to placebo.

While the 16 mg dose was evaluated as a potential treatment for adults, it was shown to confer no additional benefit for sleep initiation and was associated with higher incidences of fatigue, headache and next-day somnolence. Transient Insomnia In a randomized, double-blind, parallel-group trial using a first-night-effect model, healthy adults received placebo or Ramelteon Tablets before spending one night in a sleep laboratory and being evaluated with PSG. Ramelteon Tablets demonstrated a decrease in mean latency to persistent sleep as compared to placebo.

14.2Studies Pertinent to Safety Concerns for Sleep-Promoting Drugs Results from Human Laboratory Abuse Liability Studies A human laboratory abuse potential study was performed in 14 subjects with a history of sedative/hypnotic or anxiolytic drug abuse. Subjects received single oral doses of Ramelteon Tablets (16, 80, or 160 mg), triazolam (0.25, 0.50, or 0.75 mg) or placebo. All subjects received each of the seven treatments separated by a wash-out period and underwent multiple standard tests of abuse potential.

No differences in subjective responses indicative of abuse potential were found between Ramelteon Tablets and placebo at doses up to 20 times the recommended therapeutic dose. The positive control drug, triazolam, consistently showed a dose-response effect on these subjective measures, as demonstrated by the differences from placebo in peak effect and overall 24 hour effect. Residual Pharmacological Effect in Insomnia Trials In order to evaluate potential next-day residual effects, the following scales were used: a Memory Recal… [Excerpted — this section continues on DailyMed.]

13.1Carcinogenesis, Mutagenesis, Impairment of Fertility Carcinogenesis Ramelteon was administered to mice and rats at oral doses of 0, 30, 100, 300, or 1000 mg/kg/day (mice) and 0, 15, 60, 250, or 1000 mg/kg/day (rats). Mice and rats were dosed for two years, except at the high dose (94 weeks for male and female mice and female rats). In mice, dose-related increases in the incidence of hepatic tumors (adenomas, carcinomas, hepatoblastomas) were observed in males and females.

The no-effect dose for hepatic tumors in mice (30 mg/kg/day) is approximately 20 times the recommended human dose (RHD) of 8 mg/day based on a body surface area (mg/m 2). In rats, the incidence of hepatic adenoma and benign Leydig cell tumors of the testis was increased in males at doses ≥250 mg/kg/day. In females, the incidence of hepatic adenoma was increased at doses ≥60 mg/kg/day.

The incidence of hepatic carcinoma was increased in males and female rats at 1000 mg/kg/day. The no-effect dose for tumors in rats (15 mg/kg/day) is approximately 20 times the RHD based on mg/m 2. Mutagenesis Ramelteon was not genotoxic in the in vitro bacterial reverse mutation (Ames) assay, the in vitro mouse lymphoma TK +/- assay, and in in vivo oral micronucleus assays in mouse and rat.

Ramelteon was clastogenic in the in vitro chromosomal aberration assay in Chinese hamster lung cells. The M-II metabolite was not tested for genotoxicity. However, it was present in the test medium of the parent drug at concentrations higher than those of the parent.

Impairment of Fertility When ramelteon (doses of 6 to 600 mg/kg/day) was administered orally to male and female rats prior to and during mating and early gestation, alterations in estrus cyclicity and decreased numbers of corpora lutea, implantations, and live embryos were observed at doses greater than 20 mg/kg/day. The no-effect dose is approximately 24 times the RHD of 8 mg/day based on mg/m 2. Oral administration of ramelteon (up to 600 mg/kg/day) to male rats had no effects on sperm quality or reproductive performance.