An appeal to get NHS funding for Mysimba as a means for controlling weight has failed, with cost-regulators publishing final guidelines rejecting the drug.

The National Institute for Health and Care Excellence is not recommending Mysimba (naltrexone–bupropion) within its marketing authorisation for managing overweight and obesity in adults alongside a reduced-calorie diet and increased physical activity.

According to the Institute, while clinical trial evidence shows that a combination of the drug and lifestyle measures is more effective than lifestyle measures alone, its long-term effectiveness is unknown.

Also, its cost effectiveness estimate is “highly uncertain” because of uncertainties in the modelling assumptions, added to which, large numbers could be eligible for treatment, potentially in the long-term, leading to high overall costs.

“Therefore, in these circumstances more certainty is needed that naltrexone–bupropion will provide value for the NHS,” NICE concluded.

Consilient Health, which bought rights to commercialise and distribute Mysimba in the UK and Ireland from Orexigen in December last year, said it is “extremely disappointed” with the decision.

“Rejecting Mysimba, a clinically effective treatment that can help in the fight against obesity in the UK, limits the choice of treatment options for healthcare professionals and patients,” said its chief executive, Ahmed Al-Derzi.

The UK has the highest levels of obesity in Western Europe with a prediction that over 50 percent of its population could be obese by 2050, the firm noted, highlighting the need or new options.

“Obesity increases the risk of many illnesses such as type 2 diabetes, high blood pressure, heart disease, stroke and cancer.  As clinicians we’re already struggling to manage this huge problem and the situation is only going to worsen.  We desperately need new treatment options,” said Professor David Haslam, Professor David Haslam, a general practitioner with a special interest in obesity and cardiometabolic disease, and a physician in Obesity Medicine at the Centre for Obesity Research at Luton and Dunstable Hospital.

Mysimba has a novel mode of action that is not fully understood, but thought to target the central nervous system pathways responsible for hunger and eating, helping patients feel less hungry and resist food cravings.

The drug was approved for use in Europe in 2015.