A paper in the Drugs and Therapeutics Bulletin has placed a question mark over some of the reported additional cardiometabolic benefits of Sanofi-Aventis’ obesity pill Acomplia, saying that they may not be down to the drug alone.

Acomplia (rimonabant) was launched in the UK last year amid a shower of media attention for use alongside diet and exercise in treating overweight or obese patients with signs of dyslipidaemia and other associated risk factors.

A first-in-class offering, the drug works by selectively blocking CB1 receptors in the brain and other organs that play an important role in glucose and fat metabolism. But what really makes the Acomplia stand out is the company’s claim that it offers a particular benefit to patients with cardiometabolic risk factors - which predispose a person to conditions such as diabetes.

Benefits ‘not proven’

According to Sanofi-Aventis, an estimated 50% of the observed improvements in HbA1c – a measure of blood glucose levels, triglycerides and high-density lipoprotein in trials with Acomplia were “beyond that expected from weight loss alone.” But the DTB says this has not been proven: “In three of the trial reports, the authors state that the effects of rimonabant on HDL, triglycerides and HBA1c were partly independent of weight loss. However, it is not proven that any independent effect is wholly or partially attributable to rimonabant.”

Furthermore, the DTB paper points out that there are no published trials for Acomplia - which, it says, is currently the most expensive of the anti-obesity drugs on the market - pitting it against rival therapies such as Roche’s Xenical (orlistat).

Obesity is a huge problem across the world that is reaching epidemic portions. In the UK, the number has quadrupled in the last 25 years to nearly 10 million and, as obesity boosts the chance of developing diabetes by a factor of 80, the problem is multi-tiered.

Economic costs spiralling

The economic costs related to the condition are snowballing too; obesity costs the UK around £4 billion a year, and diabetes accounts for around 10% of the country's total healthcare budget, so Acomplia's price tag of £55 for a month's supply actually seems quite reasonable.

Acomplia is currently under review by the National Institute for Health and Clinical Excellence, which will decide on whether to add the drug to the NHS’ treatment menu.

A spokesperson for Sanofi-Aventis was not available for comment.