The acyclic CB1R inverse agonist taranabant mediates weight loss by increasing energy expenditure and decreasing caloric intake.

Cannabinoid 1 receptor (CB1R) inverse agonists are emerging as a potential obesity therapy. However, the physiological mechanisms by which these agents modulate human energy balance are incompletely elucidated. Here, we describe a comprehensive clinical research study of taranabant, a structurally novel acyclic CB1R inverse agonist. Positron emission tomography imaging using the selective CB1R tracer [(18)F]MK-9470 confirmed central nervous system receptor occupancy levels ( approximately 10%-40%) associated with energy balance/weight-loss effects in animals. In a 12-week weight-loss study, taranabant induced statistically significant weight loss compared to placebo in obese subjects over the entire range of evaluated doses (0.5, 2, 4, and 6 mg once per day) (p < 0.001). Taranabant treatment was associated with dose-related increased incidence of clinical adverse events, including mild to moderate gastrointestinal and psychiatric effects. Mechanism-of-action studies suggest that engagement of the CB1R by taranabant leads to weight loss by reducing food intake and increasing energy expenditure and fat oxidation.

Human abuse potential and cognitive effects of taranabant, a cannabinoid 1 receptor inverse agonist: a randomized, double-blind, placebo- and active-controlled, crossover study in recreational polydrug users.

INTRODUCTION: Taranabant is a cannabinoid 1 receptor inverse agonist that was in development for treatment of obesity. Because of central nervous system effects, the study was performed to assess the abuse potential and cognitive effects of taranabant in recreational polydrug users compared with phentermine, dronabinol, and placebo. METHODS: Stimulant- and cannabis-experienced polydrug users (N = 30) were randomized in a double-blind crossover study to receive taranabant 2, 4, 10, and 20 mg; phentermine 45 and 90 mg; dronabinol 20 mg; and placebo. Subjective and neurocognitive measures were administered for 24 hours, and peak/peak change from baseline effects were analyzed using a linear mixed-effects model. RESULTS: Phentermine 45 and 90 mg showed abuse-related subjective effects versus placebo, including drug liking, overall drug liking, and other positive/stimulant effects, whereas dronabinol 20 mg showed abuse-related positive, cannabis-like, and sedative effects. Taranabant was not significantly different from placebo on most of the subjective measures other than negative/dysphoric effects at the highest dose, and its effects were significantly less pronounced relative to phentermine and dronabinol on most measures. Phentermine improved cognitive/motor performance and dronabinol impaired motor/cognitive performance on some measures, whereas taranabant 4 and 20 mg had minor impairment effects on manual tracking. CONCLUSIONS: The phentermine and dronabinol results demonstrate the validity and sensitivity of the study. Taranabant did not consistently show stimulant/cannabis-like effects or abuse potential in recreational polydrug users, indicating that cannabinoid 1 receptor inverse agonists/antagonists are unlikely to be recreationally abused.

Synthesis of 7-benzyl-5-(piperidin-1-yl)-6,7,8,9-tetrahydro-3H-pyrazolo[3,4-c][2,7]naphthyridin-1-ylamine and its analogs as bombesin receptor subtype-3 agonists.

The original structure of a high-throughput screening hit obtained from an external vendor was revised based on multiple NMR studies. The active compound was re-synthesized via a novel route and its structure and biological activity as a BRS-3 agonist were unambiguously confirmed. Multi-gram quantities of the hit were prepared for pharmacokinetic and efficacy studies. The synthetic strategy allowed for the preparation of multiple analogs for SAR exploration.

Influence of taranabant, an orally active, highly selective, potent cannabinoid-1 receptor (CB1R) inverse agonist, on ethinyl estradiol and norelgestromin plasma pharmacokinetics.

Taranabant, an orally active, potent, and highly selective CB-1 receptor inverse agonist, is being developed for the treatment of obesity. This randomized, placebo-controlled, multiple-dose, crossover study evaluated the effect of taranabant on the pharmacokinetics of ethinyl estradiol and norelgestromin in healthy women receiving > or =3 months of therapy with oral contraceptives. Nineteen participants with normal menstrual cycles received oral contraceptives on days 1 to 21 during 2 consecutive contraceptive cycles. Participants received taranabant 6 mg/day or placebo on days 1 to 21 of each contraceptive cycle. Plasma samples were collected predose and 0.5, 1, 1.5, 2, 3, 4, 6, 8, 12, and 24 hours postdose on day 21 of each cycle for determination of AUC0-24 h and Cmax of ethinyl estradiol and norelgestromin. Lack of a clinically important effect was declared if the 90% confidence intervals for the geometric mean ratio of AUC0-24 h and Cmax in the absence and presence of taranabant were contained within the predefined bounds of (0.8, 1.25). The geometric mean ratios and 90% confidence intervals of ethinyl estradiol and norelgestromin, respectively, were 0.93 (0.87, 1.00) and 1.02 (0.96, 1.09) for AUC0-24 h and 0.95 (0.88, 1.01) and 0.95 (0.88, 1.01) for Cmax. In summary, coadministration of multiple-dose taranabant 6 mg with oral contraceptives did not lead to clinically meaningful alterations in the pharmacokinetic profiles of ethinyl estradiol or norelgestromin.

Effect of the cholesteryl ester transfer protein inhibitor, anacetrapib, on lipoproteins in patients with dyslipidaemia and on 24-h ambulatory blood pressure in healthy individuals: two double-blind, randomised placebo-controlled phase I studies.

BACKGROUND: The inhibition of cholesteryl ester transfer protein (CETP) is considered a potential new mechanism for treatment of dyslipidaemia. Anacetrapib (MK-0859) is a CETP inhibitor currently under development. We aimed to assess anacetrapib's effects as monotherapy on low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) and on 24-h ambulatory blood pressure. METHODS: We did two double-blind, randomised, placebo-controlled phase I studies. In the first study, 50 patients with dyslipidaemia (LDL-C 100-190 mg/dL; 40 active, 10 placebo) aged 18-75 years received anacetrapib doses of 0, 10, 40, 150, or 300 mg orally once a day with a meal for 28 days. Standard lipid and lipoprotein monitoring, safety monitoring, and anacetrapib concentrations for pharmacokinetics were done. In the second study, 22 healthy participants aged 45-75 years received either 150 mg of anacetrapib once a day or matching placebo with a meal for 10 days in each crossover period, in a randomised sequence, with at least a 14-day washout between the treatment periods. Continuous 24-h ambulatory blood pressure monitoring was done on day -1 and day 10 of each treatment period in this study. The primary or secondary endpoints of safety and tolerability were assessed in both studies by monitoring clinical adverse experiences, physical examinations, vital signs, 12-lead electrocardiogram, and laboratory safety. Analysis was per protocol. These trials are registered with ClinicalTrials.gov, number NCT00565292 and NCT00565006. FINDINGS: In the dyslipidaemia study, one patient withdrew consent and one was excluded from the data analysis for HDL-C and LDL-C because complete pre-dose measurements were not available. Anacetrapib produced dose-dependent lipid-altering effects with peak lipid-altering effects of 129% (mean 51.1 [SD 3.8]-114.9 [7.9] mg/dL) increase in HDL-C and a 38% (138.2 [11.4]-77.6 [7.9] mg/dL) decrease in LDL-C in patients with dyslipidaemia. In the 24-h ambulatory blood pressure study in healthy individuals, least squares difference between anacetrapib and placebo groups on day 10 were 0.60 (90% CI -1.54 to 2.74; p=0.634) mm Hg for systolic blood pressure and 0.47 (90% CI -0.90 to 1.84; p=0.561) mm Hg for diastolic blood pressure. INTERPRETATION: Anacetrapib seems to exhibit HDL-C increases greater than those seen with other investigational drugs in this class and LDL-C lowering effects similar to statins. Despite greater lipid-altering effects relative to other members of this class, anacetrapib seems not to increase blood pressure, suggesting that potent CETP inhibition by itself might not lead to increased blood pressure.

Safety, tolerability, pharmacokinetics, and pharmacodynamic properties of taranabant, a novel selective cannabinoid-1 receptor inverse agonist, for the treatment of obesity: results from a double-blind, placebo-controlled, single oral dose study in healthy volunteers.

Taranabant is a novel cannabinoid CB-1 receptor (CB1R) inverse agonist in clinical development for the treatment of obesity. This double-blind, randomized, placebo-controlled, single oral dose study evaluated the safety, tolerability, pharmacokinetics, and pharmacodynamics of taranabant (0.5-600 mg) in 24 healthy male volunteers. Single-dose AUC(0-infinity) and C(max) values for taranabant increased approximately linearly with dose up to 200 mg, with slightly less than dose-proportional increases in AUC(0-infinity) and C(max) values for doses >200 mg. Plasma taranabant had a biphasic disposition, with a median t(max) of 1 to 2.5 hours and a terminal elimination t((1/2)) of 38 to 69 hours. Coadministration of taranabant with a high-fat meal led to a 14% increase in C(max) and a 74% increase in AUC(0-infinity). Clinical adverse experiences associated with single doses of taranabant were generally mild and transient. Of the 198 clinical adverse experiences reported, the most common drug-related ones were nausea (36), headache (22), drowsiness (14), abdominal discomfort/abdominal pain/stomachache (14), hiccups (9), dizziness (8), decreased appetite (7), increased bowel movement (7), mood change (6), tiredness (4), vomiting (4), and sweating increased (4). Taranabant has pharmacokinetic characteristics suitable for a once-daily dosing regimen.

Multiple-dose pharmacokinetics, pharmacodynamics, and safety of taranabant, a novel selective cannabinoid-1 receptor inverse agonist, in healthy male volunteers.

Taranabant is a cannabinoid-1 receptor inverse agonist for the treatment of obesity. This study evaluated the safety, pharmacokinetics, and pharmacodynamics of taranabant (5, 7.5, 10, or 25 mg once daily for 14 days) in 60 healthy male subjects. Taranabant was rapidly absorbed, with a median t(max) of 1.0 to 2.0 hours and a t(1/2) of approximately 74 to 104 hours. Moderate accumulation was observed in C(max) (1.18- to 1.40-fold) and AUC(0-24 h) (1.5- to 1.8-fold) over 14 days for the 5-, 7.5-, and 10-mg doses, with an accumulation half-life ranging from 15 to 21 hours. Steady state was reached after 13 days. After multiple-dose administration, plasma AUC(0-24 h) and C(max) of taranabant increased dose proportionally (5-10 mg) and increased somewhat less than dose proportionally for 25 mg. Taranabant was generally well tolerated up to doses of 10 mg and exhibited multiple-dose pharmacokinetics consistent with once-daily dosing.

Influence of taranabant, a cannabinoid-1 receptor inverse agonist, on pharmacokinetics and pharmacodynamics of warfarin.

INTRODUCTION: The pharmacokinetic/pharmacodynamic effects of warfarin were assessed in the presence and absence of taranabant, an orally active, highly selective, potent, cannabinoid-1 receptor inverse agonist, which was being developed for the treatment of obesity. METHODS: Twelve subjects were assigned to two open-label treatments in fixed sequence separated by a 14-day washout. Treatment A was single-dose warfarin 30 mg on day 1. Treatment B was multiple-dose taranabant 6 mg each day for 21 days (days -14 to day 7) with coadministration of singledose warfarin 30 mg on day 1. Blood samples were collected predose and up to 168 hours postdose for assay of R(+)-and S(-)-warfarin and prothrombin time/international normalized ratio (PT/INR). RESULTS: The geometric mean ratios (GMR; warfarin+taranabant/warfarin 90% confidence interval [CI] primary endpoints) for area under the curve (AUC)(0-infinity) for R(+)-and S(-)-warfarin were 1.10 (90% CI: 1.03, 1.18) and 1.06 (90% CI: 1.00, 1.13), respectively. The GMRs (warfarin+taranabant/warfarin) for the maximum plasma concentration (C(max)) of S(-)-and R(+)-warfarin were 1.16 (90% CI: 1.05, 1.28) and 1.17 (90% CI: 1.07, 1.29), respectively. For R(+)-and S(-)-warfarin, the 90% CIs for AUC(0-infinity) GMRs fell within the prespecified bounds. Taranabant did not produce a clinically meaningful effect on PT/INR. CONCLUSION: No clinically significant alterations of the pharmacokinetics of R(+)-and S(-)-warfarin were seen following coadministration of multipledose taranabant 6 mg and single-dose warfarin 30 mg.

Antiobesity efficacy of a novel cannabinoid-1 receptor inverse agonist, N-[(1S,2S)-3-(4-chlorophenyl)-2-(3-cyanophenyl)-1-methylpropyl]-2-methyl-2-[[5-(trifluoromethyl)pyridin-2-yl]oxy]propanamide (MK-0364), in rodents.

The cannabinoid-1 receptor (CB1R) has been implicated in the control of energy balance. To explore the pharmacological utility of CB1R inhibition for the treatment of obesity, we evaluated the efficacy of N-[(1S,2S)-3-(4-chlorophenyl)-2-(3-cyanophenyl)-1-methylpropyl]-2-methyl-2-[[5-(trifluoromethyl)pyridin-2-yl]oxy]propanamide (MK-0364) and determined the relationship between efficacy and brain CB1R occupancy in rodents. MK-0364 was shown to be a highly potent CB1R inverse agonist that inhibited the binding and functional activity of various agonists with a binding K(i) of 0.13 nM for the human CB1R in vitro. MK-0364 dose-dependently inhibited food intake and weight gain, with an acute minimum effective dose of 1 mg/kg in diet-induced obese (DIO) rats. CB1R mechanism-based effect was demonstrated for MK-0364 by its lack of efficacy in CB1R-deficient mice. Chronic treatment of DIO rats with MK-0364 dose-dependently led to significant weight loss with a minimum effective dose of 0.3 mg/kg (p.o.), or a plasma C(max) of 87 nM. Weight loss was accompanied by the loss of fat mass. Partial occupancy (30-40%) of brain CB1R by MK-0364 was sufficient to reduce body weight. The magnitude of weight loss was correlated with brain CB1R occupancy. The partial receptor occupancy requirement for efficacy was also consistent with the reduced food intake of the heterozygous mice carrying one disrupted allele of CB1R gene compared with the wild-type mice. These studies demonstrated that MK-0364 is a highly potent and selective CB1R inverse agonist and that it is orally active in rodent models of obesity.