西布曲明事件后丁香园专访了加拿大和英国的两位医学专家,这两位专家关于sibutramine和SCOUT的文献分别发表在07年的LANCET和05年的EUROPEAN HEART JOURNAL SUPPLEMENTS上,文献被引用次数位居全球前十。
Dr Raj S Padwal MD(Department of Medicine, University of Alberta Hospital, Edmonton, AB, Canada)
Q:西布曲明于1997年被批准上市,在您的一篇论文中就提到截止到2007年所有的减肥药临床试验都受受试者高撤出率的影响并缺乏相关发病疾病率和死亡率的数据。在缺乏大量的临床安全数据的支持下您是否觉得西布曲明被批准上市有些早?
A:I think that there have been enough problems with antiobesity drugs (sibutramine, rimonabant, phen-fen, aminorex and others) that performing moribidity and mortality trials (mortality, cardiovascular endpoints) should be mandatory.In order to speed up the release of potentially useful drugs and because such trials take a long time to conduct, I feel that drugs should still be approved. But, as a condition of approval, these studies should be done. It took too long (13 years) for the scout trial to be performed in my opinion. One should be able to perform these studies within about 5-7 years of release, especially if they are planned prior to release of the drug.
Q:EMA于2010年1月27建议在欧盟暂停含西布曲明药品的市场许可,FDA 10月8日才宣布停止处方和使用西布曲明的建议,您是否认为FDA的决定显得有些滞后,您认为FDA推迟做决定主要是基于什么样的想法?
A:The FDA decision is based upon the results of the scout trial. This study was conducted in response to the emea’s concerns about the safety of the drug. I’m guessing that emea was able to review the study data earlier than the FDA and, hence the decision came earlier.
I don’t feel that theFDA’s decision was overly delayed. I think that they needed to review all of the evidence themselves and come to an independent conclusion.
I think that they are concerned about potential cardiovascular toxicity. The scout trial was published in the new england journal of medicine this year (volume 363 page 905). the drug significantly increased the risk of the primary endpoint, which was a composite endpoint of nonfatal myocardial infarction, nonfatal stroke, resuscitation after cardiovascular arrest and death).
I have stopped using sibutramine. Even before these results I rarely used it because I was waiting for the results of scout. I would recommend that the drug not be used.
Prof. W. Philip T. James (Hon. Professor of Nutrition, London School of Hygiene and Tropical Medicine .President, International Association for the Study of Obesity (IASO))
Q:FDA和EMA基于SCOUT实验的结果对减肥药西布曲明采取了召回的政策。您对FDA和EMA对西布曲明召回政策怎么看?国外是否也有类似的减肥药在进行或者什么样的药物才能进行类似SCOUT的大型的临床实验研究?
A:At the moment the FDA and EMEA seem to be taking an extremely cautious approach to obesity drugs in part because these may be taken by hundreds of millions of people who may have a variety of complications e.g. diabetes and cardiovascular disease. It is noteworthy that the FDA has not accepted the use of a combination of topiramate and phentermine and they are about to give their opinion on another combination of naltrexone and bupropion.
The approach to sibutramine is really very interesting. We observed an increased risk of non fatal heart attacks and strokes in those SCOUT patients who should never have taken the drug in the first place. The regulatory agencies, however, considered it entirely correct to extrapolate backwards to people at lower risk even though they do not do this for many other drugs where they see benefit in some groups of patients but exclude the use of the drug in other higher risk groups. It is therefore clear to me that the normal FDA and EMEA officials and their advisors do not believe that weight loss as such is very important and consider benefit really in terms of lowering death and cardiovascular incidence rates.
Actually we had very low death rates in SCOUT and this surprised us given how we recruited such high risk patients. We are now looking at the relationship between weight loss and mortality and morbidity for the whole SCOUT group to assess the value of weight loss as such.
There are a number of drugs in development but now if there is any sign of a higher blood pressure or pulse rate in the active treatment group we think they will ask for a SCOUT like trial testing for cardiovascular events.
We did find a lower event rate depending on weight loss but were not allowed to include this in the New England Journal paper as the analysis was not done on only the randomised groups - we will set this out in detail later.