Takeda and Orexigen announced that the Food and Drug Administration (FDA) has approved Contrave (naltrexone HCl and bupropion HCl) extended-release tablets as adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) >30kg/m2 (obese) or >27kg/m2 (overweight) in the presence of at least one weight-related comorbid condition.
Contrave combines naltrexone, an opioid antagonist, and bupropion, a relatively weak inhibitor of the neuronal reuptake of dopamine and norepinephrine.The exact neurochemical effects of Contrave in weight loss are not fully understood.
The FDA approval was based on four 56-week multicenter, double-blind, placebo-controlled trials (COR-I, COR-II, COR-BMOD, and COR-Diabetes) to examine Contrave in conjunction with lifestyle modification in patients randomized (n=4536) to Contrave or placebo. Co-primary efficacy endpoints were percent change from baseline in body weight and proportion of participants who achieved a decrease in body weight of >5%.
Patients using Contrave at the maintenance dose should be evaluated after 12 weeks to determine if the treatment is working. If a patient has not lost at least 5% of baseline body weight, Contrave should be discontinued, as it is unlikely that the patient will achieve and sustain clinically meaningful weight loss with continued treatment.
Because it contains bupropion, Contrave has a boxed warning to alert health care professionals and patients to the increased risk of suicidal thoughts and behaviors associated with antidepressant drugs. The warning also notes that serious neuropsychiatric events have been reported in patients taking bupropion for smoking cessation.
Contrave will be available in 8mg/90mg extended-release tablets in 120-count bottles. Contrave is expected to launch in the fall of 2014.