The study, which focused on 6,000 patients, showed a loss of six to nine kilograms during a year, a more significant loss than that caused by other medicines on the market.
The drug also lowers blood fats and improves insulin sensitivity. It has even been shown to help people stop smoking and lose weight, or at least not go up in weight.
Those who stop taking the drug could put weight on quickly and have mood swings.
“We see this as enormously important research with serious objectives and great development potential,” said Peter Myrenfors, spokesman for the drug company Sanofi-Aventis, the medicine’s maker.