It has not been a good few years for anti obesity drugs. Acomplia (Rimonabant) was withdrawn from the market in October 2008 and in January 2010 Reductil (Sibutramine) had its marketing authorization suspended across the whole of the EU following the publication of some data that suggested that the drug could increase the risk of non-fatal cardiovascular events in patients with a pre-existing heart condition.
With obesity a growing problem in the UK as well as in the rest of the Western world, finding a safe but effective anti obesity drug is an attractive area for investment for the pharmaceutical industry. There are a number of slimming pills in clinical trials but perhaps the most promising from a perspective of efficacy is a drug called Qnexa. In clinical trials Qnexa proved to be more effective than any weight loss drug that has ever gone before it (other than perhaps the disastrous Fen-Phen, which had to be pulled from the market several years ago because of serious cardiovascular side effects.) Patients on a high dose of Qnexa lost up to fifteen per cent of their body weight and even those on a low dose lost up to eight per cent over a 56 week period.
Qnexa is in the process of being assessed by the Foods and Drugs Administration, the USA’s drug watchdog, so it is about to face its toughest hurdle. Although Qnexa contains phentermine (the less harmful but potentially addictive component of Fen-Phen) and Topiramate (a drug that is currently prescribed for epilepsy and has been linked to dull headedness and depression) the preliminary outlook for Qnexa from a side effects perspective is quite positive with only minor possible side effects including nausea, dry mouth and insomnia being identified.
Even if Qnexa is approved, it may well be that more serious side effects are only noticed after the drug gets its license as has happened in the past. Acomplia was never licensed in the US but it was given the green light in the EU and had to be pulled from the shelves after 18 months. The problem with Acomplia stemmed from the psychiatric side effects that it had on certain people. There was an increased incidence of depression in patients being treated with Acomplia and, in extreme cases, suicidal ideation was recorded.
It may be that Vivus (the company behind Qnexa) has hit on just the right combination of existing drugs to provide a safe and effective weight loss (and we at The Online Clinic certainly hope so) but the history in this area is not attractive, with the pharmaceutical graveyard littered with once promising anti-obesity drug candidates.