Obesity – Acomplia: loss of a few kilos, many questions

Acomplia ( Rimonabant ), a CB1 cannabinoid receptor antagonist, was approved by EMEA ( European Medicines Agency ) for the adjuvant treatment of obesity, in combination with a low-calorie diet and physical exercise.

Rimonabant is used together with diet and exercise to treat adult patients:

who are obese with a body mass index ( BMI ) greater or equal to 30 kg/m², or

who are overweight ( BMI greater or equal to 27 kg/m² ) and also have other risk factor(s), such as type 2 diabetes or dyslipidaemia.

RIO ( Rimonabant In Obesity and related disorders ) is a large phase 3 programme ( > 6600 patients ) evaluating the efficacy and safety of Rimonabant ( 5 or 20 mg/day ) in obese or overweight patients with or without comorbidities ( RIO-Europe and RIO-North America ), with untreated dyslipidaemia ( RIO-Lipids ) or with type 2 diabetes treated with Metformin or sulfonylurea ( RIO-Diabetes ).

The trials have shown that, when combined with a low-calorie diet, Rimonabant 20 mg/day leads to an average weight loss of 4 or 5 kg more than placebo after one year of treatment.
This is similar to the weight loss reported with Orlistat ( Xenical ) ( indirect comparison ).
Effects on the lipid profile are similar to those reported with Sibutramine ( Meridia/Reductil ).

Rimonabant has not been shown to reduce morbidity or mortality.

Patients regain the weight they lost within about 9 months after Rimonabant withdrawal.

During the studies, the side effects that were more commonly observed ( more than 1 patient in 10 ) were nausea and infections of the upper respiratory tract. Among the common side effects ( seen in between 1 and 10 patients in 100 ), side effects such as mood alterations, anxiety, depression, sleep disorders, were seen more with Rimonabant than with placebo.

The possible long-term adverse effects of Rimonabant are unknown.

In February 2006 the FDA told Sanofi-Aventis, the manufacturer of Acomplia, it would need further information on Rimonabant before it would be approved for the U.S. market.


1) Prescrire International, 2006

2) EMEA, 2006