Obesity is associated with increased mortality and morbidity and represents a worldwide epidemic that is increasing in prevalence and remains a significant problem in Canada and a burden on our healthcare system. Maintaining long-term weight loss is the "Achilles' heel" of obesity therapy. Since obesity is considered a chronic disease, we need better interventions than continued calorie restriction and increased physical activity.
Sustained weight loss during the first year is a predictive factor for successful weight loss after 4 years. Clinical trials employing an intensive lifestyle intervention demonstrate that a 5-10% weight loss translates into important reductions in metabolic and cardiovascular risk factors. This benefit however, is quite often mitigated by weight regain which could occur in approximately 50% of patients after 1 year. Further behaviour modification/lifestyle intervention and or pharmacotherapy are the main pillars for treating weight regain or achieving weight maintenance. This study will refine our knowledge and understanding about the most appropriate treatment for weight maintenance.
Contrave (naltrexone HCl and bupropion HCl) extended-release tablet is an approved drug and indicated to be used with a low calorie diet and increased physical activity for chronic weight management in obese adults (BMI 30 Kg/m2 or greater) or overweight adults (BMI 27 Kg/m2 or greater) with at least one weight related condition such as hypertension or diabetes. Presently we do not have any evidence for the use of Contrave for weight maintenance.
This is a 1 year, phase 4, prospective, pragmatic, randomized, double-blind, placebo controlled and crossover, observational study that will be conducted in two 6 month phases, across multiple Bariatric Centres of Excellence (BCoE) in Ontario. The first 6 months is the randomized, double blind, placebo controlled phase and participants will be randomly assigned to receive Contrave with usual care (dietary and behaviour counselling) or placebo with usual care. At 6 months and the end of the blinded phase, all participants will be administered Contrave for the remaining 6 month, open-label phase of the study. In other words, participants randomly allocated to receive Contrave will continue on Contrave for the final 6 months, and participants randomly assigned to placebo will crossover to treatment with Contrave for the final 6 months. All subjects will also continue to receive usual care.
The study includes several follow up visits to assess safety and treatment effects, some in person and others by telephone or video conferencing. Body weight, blood pressure, heart rate, waist circumference, lab tests, and subject completed questionnaires will be collected as part of usual care or for the study. Changes in medications and any possible side effects will also be monitored during the study.
To qualify, men and women must successfully complete the BCoE behaviour modification program and demonstrate ≥ 5% weight loss. All participants will be followed for 1 year with multiple visits to assess safety and treatment effects.
This study aims to demonstrate that in participants who have ≥ 5% weight loss following the completion of a behaviour modification program with meal replacements, Contrave combined with usual care will significantly improve maintenance of weight loss and promote further weight loss, compared to placebo with usual care.
