A clinical trial assessing the safety and efficacy of the CB1R inverse agonist taranabant in obese and overweight patients: low-dose study.

ABSTRACT

OBJECTIVE: To evaluate the weight loss efficacy, safety and tolerability of taranabant, a CB1R inverse agonist, in obese and overweight patients. DESIGN: Multicenter, double-blind, randomized, placebo-controlled study. SUBJECTS: Patients >or=18 years old, BMI 27-43 kg m(-2), were randomized to placebo (n=209) or taranabant 0.5 mg (n=207), 1 mg (n=208) or 2 mg given orally once daily (n=417) for 52 weeks. MEASUREMENTS Key efficacy measurements included body weight (BW), waist circumference (WC), lipid endpoints and glycemic endpoints. RESULTS: Based on a last observation carried forward analysis of the all-patients-treated population, mean change in BW for taranabant 0.5, 1, and 2 mg and placebo was -5.4, -5.3, -6.7 and -1.7 kg, respectively (P<0.001 for all doses vs placebo). The proportions of patients who lost at least 5 and 10% of their baseline BW at week 52 were significantly higher for all taranabant doses vs placebo (P<0.001 for all doses). Reductions in WC, percentage of body fat, and triglycerides were significant for taranabant 2 mg and in triglycerides for taranabant 1 mg vs placebo. There was no effect of taranabant vs placebo on other lipid or glucose-related endpoints. Incidences of adverse experiences classified in the gastrointestinal (diarrhea and nausea), nervous system (dizziness/dizziness postural), psychiatric-related (irritability and anger/aggression) and vascular (flushing/hot flush) organ systems were higher and statistically significant in the taranabant 2-mg group compared with the placebo group. Irritability was higher and statistically significant in all taranabant groups compared with the placebo group. CONCLUSION: All three doses of taranabant-induced clinically meaningful and statistically significant weight loss. Incidences of adverse experiences in organ systems known to express CB1R were higher in taranabant groups.