Shah Rashmi R
Rashmi Shah Consultancy Ltd, Gerrards Cross, Buckinghamshire, UK.
Drug Saf. 2007;30(12):1093-110. doi: 10.2165/00002018-200730120-00003.
December 2007 marks the 10-year anniversary of the first regulatory guidance for evaluation of drug-induced QT interval prolongation. A decade on, it seems surprising that this document, which was released by the Committee on Proprietary Medicinal Products, caused such acrimony in the industry. Sponsors now routinely evaluate their new drugs for an effect on cardiac electrophysiology in preclinical studies, in addition to obtaining ECGs in all phases of drug development and conducting a formal thorough QT study in humans.However, concurrently, new concerns have also emerged on broader issues related to the cardiovascular safety of drugs because of their potential to shorten the QT interval as well as to induce proischaemic, profibrotic or prothrombotic effects. Drugs may also have an indirect effect by adversely affecting one or more of the cardiovascular risk factors (e.g. through fluid retention or induction of dyslipidaemia). In addition to peroxisome proliferator-activated receptor agonists and cyclo-oxygenase 2 selective inhibitors, three other drugs, darbepoetin alfa, pergolide and tegaserod, provide a more contemporary regulatory stance on tolerance of cardiovascular risk of drugs and their benefit-risk assessment. This recent, more assertive, risk-averse stance has significant implications for future drug development. These include the routine evaluation of cardiovascular safety for certain classes of drugs. Drugs that are intended for long-term use will almost certainly require long-term clinical evaluation in studies that enrol populations that most closely resemble the ultimate target population. Novel mechanisms of action and biomarkers by themselves are no guarantee of improved safety or benefits. Even some traditional biomarkers have come to be viewed with scepticism. Requirements for more extensive and earlier postmarketing assessment of clinical benefits and rare, but serious risks associated with new medicinal products should create a new standard of evidence for industry and regulators and almost certainly result in better assessment of benefit/risk, more effective and balanced regulatory actions and better care for patients.
2007年12月标志着首个药物所致QT间期延长评估监管指南发布10周年。十年过去了，由专利药品委员会发布的这份文件在业内引发如此激烈的争论，这似乎令人惊讶。如今，申办方除了在药物研发的各个阶段获取心电图并在人体中进行正式的全面QT研究外，还会在临床前研究中常规评估其新药对心脏电生理的影响。然而，与此同时，由于药物有缩短QT间期以及诱发促缺血、促纤维化或促血栓形成效应的可能性，关于药物心血管安全性的更广泛问题也出现了新的担忧。药物也可能通过对一种或多种心血管危险因素产生不利影响而产生间接作用（例如通过液体潴留或诱发血脂异常）。除过氧化物酶体增殖物激活受体激动剂和环氧化酶2选择性抑制剂外，另外三种药物，即聚乙二醇化促红细胞生成素、培高利特和替加色罗，为药物心血管风险耐受性及其效益风险评估提供了更具时代性的监管立场。这种最近更坚定、规避风险的立场对未来药物研发具有重大影响。这些影响包括对某些类别的药物进行心血管安全性的常规评估。打算长期使用的药物几乎肯定需要在纳入与最终目标人群最相似人群的研究中进行长期临床评估。新的作用机制和生物标志物本身并不能保证安全性或效益得到改善。甚至一些传统生物标志物也开始受到质疑。对新药品相关的临床效益以及罕见但严重风险进行更广泛和更早的上市后评估的要求，应为行业和监管机构创造新的证据标准，几乎肯定会带来更好的效益/风险评估、更有效和平衡的监管行动以及对患者更好的护理。
