The RIO Europe study has been presented already back in 2004. Now the new drug Rimonabant has been launched in England. Other European countries will follow soon (e.g. Germany in September 2006). This drug has completely different mode of action comparing to older weight loosing drugs. It blocks one of the possible receptors for the most effective agent found in cannabis (i.e. marijuana). The RIO study took 2 years investigating 1507 obese patients using 2 different dosages of the drug compared to placebo (no agent at all). The patients in the higher dose group lost more weight on average 8.6 kg. Patients in the low dose group lost 4.8 kg and the control group on placebo also lost 3.6 kg in the first study year. The study has been accompanied by simple lower calorie diet. The patients didn’t just loose weight but also their waist got slimmer. Many blood parameters like lipids improved. The metabolism improved as well and the chance to get diabetes decreased. Side effects were mostly mild and transitory. Most common side effects were nausea, diarrhoea and dizziness. The complete RIO study program is based on 6600 patients worldwide. Rimonabant also helps to quit smoking; however, this indication has not been registered yet. It is a very promising approach, however it has to be taken into account that both the patient number as well as the length of observation period are not sufficient to find other and possibly severe adverse effects. The biggest field study is actually starting now when many people suffering under their weight will start to take the drug. The price of 80 Euro for one monthly dose is pretty saucy especially considering that you may keep the lost weight only continuing to take it.
Update - On Oct. 23, 2008 the marketing of rimonabant (Acomplia) in Europe has been suspended by the manufacturer due to its possible adverse effects, such as neurological and psychiatric side effects, including depression and "suicidal ideation," which are described in the package insert in Europe. These effects were enough to persuade an FDA advisory committee in June 2007 that the drug should not be marketed in the US.
The development of similar drugs has been also halted by other manufacturers.