Combination therapy with naltrexone and bupropion for obesity reduces total and visceral adiposity

Smith, S. R., Fujioka, K., Gupta, A. K., Billes, S. K., Burns, C., Kim, D., Dunayevich, E., Greenway, F. L.

This trial was sponsored by Orexigen Therapeutics, Inc. Brandon Walsh, PhD, an employee of Orexigen Therapeutics, Inc., assisted in the writing of the manuscript.

The effects of combination naltrexone/bupropion therapy on body composition and visceral adipose tissue (VAT) mass were examined in a subset (n=107) of obese subjects from a Phase 2 trial that compared the efficacy and safety of placebo, naltrexone monotherapy, bupropion monotherapy or one of three naltrexone/bupropion dose combinations for 24 weeks. Body composition data were obtained using dual-energy X-ray absorptiometry and computed tomography. Eighty subjects completed the substudy. Naltrexone/bupropion resulted in weight loss and a greater reduction in body fat (-14.0 +/- 1.3%) than placebo (-4.0 +/- 2.0%), naltrexone monotherapy (-3.2 +/- 2.5%) and bupropion monotherapy (-4.1 +/- 2.9%; all p<0.01). Reduction in VAT mass was also greater with naltrexone/bupropion (-15.0 +/- 1.8%) than placebo (-4.6 +/- 2.7%), naltrexone monotherapy (-0.1 +/- 3.5%) and bupropion monotherapy (-2.3 +/- 4.2%; all p<0.01). Reductions in body fat and VAT mass with naltrexone/bupropion were proportional with weight loss. Weight loss with naltrexone/bupropion was not associated with a greater relative reduction in lean mass than placebo or the monotherapies.

Combination therapy with naltrexone and bupropion for obesity reduces total and visceral adiposity Article