New obesity treatment rejected by NICE

Naltrexone/bupropion is not recommended within its marketing authorisation for managing overweight and obesity in adults alongside a reduced-calorie diet and increased physical activity.

NICE acknowledged clinical trial evidence showing that naltrexone/bupropion in combination with lifestyle measures is more effective than lifestyle measures alone, but noted that the combination's long-term effectiveness is unknown.

The appraisal committee felt that the cost effectiveness of naltrexone/bupropion could not be definitively calculated because of uncertainties in the modelling assumptions. Given that large numbers of people could be eligible for long-term treatment, the committee concluded that more certainty is needed that naltrexone/bupropion will provide value for the NHS.

Mysimba is indicated as an adjunct to a reduced-calorie diet and increased physical activity for the management of weight in adults with an initial BMI of ≥30kg/m² (obese), or ≥27kg/m² to <30kg/m² (overweight) in the presence of one or more weight-related co-morbidities, such as type II diabetes, dyslipidaemia, or controlled hypertension.

Naltrexone is a μ-opioid antagonist and bupropion a weak inhibitor of neuronal dopamine and noradrenaline reuptake. The two drugs are thought to have complementary actions on CNS pathways regulating body weight.