New Weight Loss Drug Makes Progress

One year ago millions of obese Americans were waiting to hear whether or not the Food and Drugs Agency would give approval to the diet drug rimonabant (Acomplia). Obviously there was huge disappointment when this approval was not given. Rimonabant never actually made it to the American market although it is thought that the patent holder will return for another bite of the cherry at a later date, armed with deeper clinical trial data.

There is, therefore, a great deal if excitement over Merck's new diet drug taranabant. The results from the second phase of testing were encouraging and now after another two years of testing it seems that the results for phase three may be equally exciting, though the final report is yet to be published.

Researchers announced that study participants taking varying doses of taranabant lost 8 to 14 pounds over a 12-week period. There was one question, however, which still remains unanswered. Does taranabant have less significant side effects than rimonabant? Both drugs work in a similar way, by targeting particular receptors in the brain. Acomplia, however, was not approved by the FDA after concerns were raised over its psychiatric side effects which may include depression and suicidal thoughts in patients prone to mental health problems. So how does taranabant compare? Initial feedback seems to suggest that between one-fifth and one-third of patients had experienced adverse side effects which included depressed mood, irritability, anger, mood swings and insomnia. Unlike rimonabant, however, patients reported no suicidal thoughts though it was conceded that the question had not been asked in a systematic way.

There will, of course, have to be more conclusive evidence provided before the FDA grants approval to the new drug. The company expects the phase III report to be published later this year and for taranabant to be submitted for FDA approval before the end of 2008. Taranabant will also be submitted to the European Medicines Agency although it is believed that Merck wants to get it approved in the US first.

Taranabant is a CB1 receptor reverse agonist which is slightly different form Acomplia, which is a CB1 receptor antagonist. Although they are both targeting the endocannabinoid system, the slightly different way in which they work could be crucial. Acomplia was approved for use in the UK in June 2006 and since then it has helped a number of people to lose weight but many have been disappointed by the lack of progress and ceased treatment after one or two months. Many also found the cost of this medication on private prescription to be prohibitive. The unfortunate thing is that all new weight loss drugs seem to get hyped up by the media and this ultimately leads to disappointment as the results, for most people, rarely match the hype. It cannot be emphasised enough that weight loss medications should only ever be used as an adjunct to diet and exercise. Obesity is a burgeoning problem in gthe West and medications that get regulatory approval do work but there has to be some effort on the part of the patient.