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临床试验与新冠疫情

Clinical trials and the COVID-19 pandemic.

作者信息

Retsas Spyros

机构信息

Former Consultant Medical Oncologist, Formerly, Lead Clinician of the Melanoma Unit, Imperial College at Charing Cross Hospital, London, U.K.

出版信息

Hell J Nucl Med. 2020 Jan-Apr;23(1):4-5. doi: 10.1967/s002449912014.

Abstract

"...but why think? Why not try the experiment?..." John Hunter (1728-1793), in a letter to Edward Jenner. August 2, 1775. When Galen of Pergamum (2 c. A.D.), physician, philosopher and experimentalist, sought to ascertain the therapeutic properties of Theriac, an antidote of repute against poisons, he resorted to an experiment. Theriac or Theriaca was a compound drug, containing in some versions used in antiquity numerous components; Galen's own composition included over 70 ingredients! One of its uses was as an antidote against snakebites, a frequent peril for the Roman armies marching on in sandals. Galen spent most of his life in Rome and was elevated to Imperial Physician at the court of Marcus Aurelius, who apparently took daily doses of Theriac, which among other components included opium. Describing the experiment to his friend Pison, Galen wrote, "as I could not possibly conduct a trial on humans, I experimented on roosters" For his experiment, Galen, studied two groups of roosters, but he doesn't tell us how many animals he included in each category. Both groups were exposed to poisonous snakebites. All roosters who were fed with theriac prior to exposure to viper bites survived, whereas in the second group that had not received prophylactic Theriac, all roosters died. Not only is Galen's methodology remarkable, preceding the modern randomised trial by eighteen centuries, but more importantly, it is notable for his ethical stance at a time when sensitivities about human rights, prevalent in our times, were largely absent in societies of widespread slavery. For example, Mithridates VI (132-63 BC), the King of Pontus who is credited with the first use of Theriac, tested its efficacy on criminals and slaves. For his experiment Galen used the random allocation of treatment, today's prospective randomised clinical trial, implemented in the evaluation of novel therapies, widely used internationally, particularly in cancer research! This experimental method used for ascertaining the efficacy of new drugs became established after the second half of the 20 century and is now firmly entrenched as a research tool. On the other hand, the retrieval of information from observational studies or non-randomised series is considered scientifically inferior and is often dismissed or ignored as irrelevant or anecdotal. Such is the compulsion for the randomised study that in the midst of the COVID-19 pandemic, respected physicians and scientists appeared in the media hesitant to recommend the use of protective facial masks, as there was no evidence of benefit for their use from prospective randomised studies in the general population! Logic had no place in the argument! COVID-19, caused by the SARS-CoV-2 new corona virus, brought to the fore the randomised trial, as well as, the ethical dilemmas that surround the allocation of treatment at random, in the face of a devastating pandemic. Anthony Fauci, distinguished infectious diseases expert and an adviser to the President of the USA, at a recent briefing from the Situation Room of the White House, endorsed categorically and unreservedly the randomised trial for the evaluation of drugs potentially effective against SARS-CoV-2, in patients afflicted with COVID-19. A few days later on April 8, 2020, Professor Sotiris Tsiodras, scientific advisor to the Greek Government for COVID-19 and an expert on infectious diseases, when asked by a journalist about chloroquine, he responded, "Antony Fauci is correct. Nevertheless, we give the drug to everyone, that is, not half of the patients will receive it, and the other half will not". If we accept that the randomised trial represents the unique, impregnable method of evaluating new treatments-several clinicians dispute this dogma. -the question arises how will treatments be allocated to patients? According to the Declaration of Helsinki participation of a subject in a clinical trial requires their explicit written consent. Will, a potentially hypoxic patient rapidly deteriorating, be able to understand what is being asked of them, and will that patient be in a position to provide consent? And if that patient refuses to be randomised, what are the options? Is it his/her right to request the active treatment that a fellow patient is receiving in the next bed? Although the Declaration of Helsinki allows the option of no treatment or even placebo, where no known treatment is available for a certain condition, such as COVID-19, it also emphasizes that "while the primary purpose of medical research is to generate new knowledge, this goal can never take precedence over the rights and interests of individual research subjects". Consider now the physicians and nurses on the first line of the battle against the pandemic; to the enormous pressures and risks that they experience daily, they may have to endure the added psychological burden of the randomised trial, knowing that half of their patients are receiving the promising drug, whilst the other half are denied the chance of potential benefit. When during the Medical Research Council's randomized trial of streptomycin, one senior physician contracted tuberculosis, the Medical Research Council obtained supplies for him outside the trial. In this brief instance of medical history, the equipoise, the scientific imperative, all arguments and other justifications for providing treatment at random, were thrown out of the window in favour of the human factor! Why is randomization necessary? Because-it is presumed-the process of randomising subjects, protects the study from the selective inclusion of patients with favourable characteristics, thus inadvertently allowing or facilitating a falsely favourable result for the drug or treatment under investigation. However, the process of randomising patients does not necessarily result in the randomisation of the characteristics of their disease. Exactly because of this, at the end of a randomised study, even if the prognostic variables are evenly represented and balanced in the strata, further confirmation of the result is sought with a statistical multifactorial analysis. Such multifactorial analyses can also be applied to a non-randomised group of patients engaged in the trial of a new drug. Since the middle of the 20 century a generation of physicians have been trained to dismiss, or are incapable of evaluating the validity of a treatment beyond the established etiquette of the randomised study. This, some have argued, constitutes intellectual indolence, it is not scientific robustness. Pandits foresee that the world will be different after the end of this pandemic. Perhaps human ingenuity will seek new investigative methods that will render the randomised clinical trial obsolete, both, on methodological and ethical grounds. Until then and even if we have to accept the scientific supremacy of the randomised study in the evaluation of novel therapies, the ethical considerations in the unprecedented circumstances of a relentless pandemic demand a more humane approach, befitting the beneficent precepts of the Hippocratic tradition.

摘要

“……但为什么要思考呢?为什么不试试这个实验呢?……”约翰·亨特(1728 - 1793),在1775年8月2日写给爱德华·詹纳的一封信中说道。当帕加马的盖伦(公元2世纪),这位医生、哲学家兼实验家,试图确定解毒剂“解毒万灵药”的治疗特性时,他诉诸了一项实验。解毒万灵药是一种复方药物,在古代使用的某些配方中含有众多成分;盖伦自己配制的成分包含70多种!它的用途之一是作为蛇咬伤的解毒剂,对于穿着凉鞋行军的罗马军队来说,蛇咬是常有的危险。盖伦一生大部分时间都在罗马,并被提升为马可·奥勒留宫廷的御医,马可·奥勒留显然每天都服用解毒万灵药,其成分中除其他外还包括鸦片。在向他的朋友皮森描述这个实验时,盖伦写道:“由于我不可能在人类身上进行试验,我就在公鸡身上做了实验。”为了他的实验,盖伦研究了两组公鸡,但他没有告诉我们每组中有多少只动物。两组公鸡都被暴露于毒蛇咬伤。所有在接触蝰蛇咬伤之前喂食了解毒万灵药的公鸡都存活了下来,而在第二组未接受预防性解毒万灵药的公鸡中,全部死亡。盖伦的方法不仅卓越,比现代随机试验早了18个世纪,更重要的是,在一个人权观念在广泛存在奴隶制的社会中基本缺失的时代,他的伦理立场值得注意。例如,本都国王米特拉达梯六世(公元前132 - 63年),被认为是第一个使用解毒万灵药的人,他在罪犯和奴隶身上测试其功效。盖伦在他的实验中使用了治疗的随机分配,即当今在评估新疗法时实施的前瞻性随机临床试验,在国际上广泛使用,尤其是在癌症研究中!这种用于确定新药疗效的实验方法在20世纪下半叶之后确立,现在已牢固地作为一种研究工具。另一方面,从观察性研究或非随机系列中获取信息在科学上被认为是 inferior(此处原文有误,推测可能是“inferior”,意为“较差的”),并且常常被视为无关紧要或轶事而被摒弃或忽视。对随机研究的这种强制要求以至于在新冠疫情期间,备受尊敬的医生和科学家在媒体上显得犹豫不决,不敢推荐使用防护口罩,因为在普通人群的前瞻性随机研究中没有证据表明使用口罩有益!逻辑在这场争论中毫无立足之地!由新型冠状病毒SARS-CoV-2引起的新冠疫情凸显了随机试验以及在面对毁灭性大流行时围绕随机分配治疗的伦理困境。美国著名传染病专家、总统顾问安东尼·福奇,在最近一次从白宫情况室举行的简报会上,明确且毫无保留地支持对感染新冠病毒的患者进行随机试验,以评估对SARS-CoV-2可能有效的药物。几天后的2020年4月8日,希腊政府新冠疫情科学顾问、传染病专家索蒂里斯·齐奥德拉斯教授,当被一名记者问及氯喹时,他回答说:“安东尼·福奇是正确的。然而,我们给每个人使用这种药物,也就是说,不是一半患者会使用它,而另一半不会。”如果我们接受随机试验代表评估新疗法的独特、坚不可摧的方法——一些临床医生对此教条提出质疑——那么问题就来了,如何将治疗分配给患者呢?根据《赫尔辛基宣言》,受试者参与临床试验需要他们明确的书面同意。一个可能处于低氧状态且病情迅速恶化的患者,能够理解对他们的要求吗?那个患者能够提供同意吗?如果那个患者拒绝被随机分组,有哪些选择呢?要求接受隔壁病床另一位患者正在接受的积极治疗是他/她的权利吗?尽管《赫尔辛基宣言》允许在没有已知治疗方法可用于某种病症(如新冠疫情)时选择不治疗甚至使用安慰剂,但它也强调“虽然医学研究的主要目的是产生新知识,但这个目标绝不能优先于个体研究受试者的权利和利益”。现在考虑一下抗击疫情一线的医生和护士;在他们每天所承受的巨大压力和风险之上,他们可能不得不忍受随机试验带来的额外心理负担,因为他们知道一半的患者正在接受有前景的药物治疗,而另一半则被剥夺了潜在受益的机会。在医学研究委员会对链霉素进行随机试验期间,一位资深医生感染了肺结核,医学研究委员会在试验之外为他获取了药物供应。在这段简短的医学史中,平衡、科学必要性以及所有关于随机提供治疗的论据和其他理由,都为了人文因素而被抛诸脑后!为什么随机化是必要的呢?因为——据推测——随机分配受试者的过程可以保护研究免受具有有利特征的患者被选择性纳入的影响,从而无意中允许或促成了对所研究药物或治疗的虚假有利结果。然而,随机分配患者的过程并不一定会导致其疾病特征的随机化。正是因为这个原因,在随机研究结束时,即使预后变量在各层中均匀呈现且平衡,仍会通过统计多因素分析来进一步确认结果。这种多因素分析也可以应用于参与新药试验的非随机患者组。自20世纪中叶以来,一代医生被训练去摒弃,或者无法评估超出随机研究既定规范的治疗有效性。一些人认为,这构成了智力上的懒惰,而不是科学上的稳健。学者们预见,在这场大流行结束后,世界将会不同。也许人类的智慧会寻求新的研究方法,使随机临床试验在方法和伦理层面都过时。在此之前,即使我们不得不接受随机研究在评估新疗法方面的科学至上地位,但在无情大流行的前所未有的情况下,伦理考量需要一种更人道的方法,这符合希波克拉底传统的慈善戒律。

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