Unique challenges arise when conducting trials to evaluate therapies already in common clinical use, including difficulty enrolling patients owing to widespread open-label use of trial therapies and the need for large sample sizes to detect small but clinically meaningful treatment effects. Despite numerous successes in trials evaluating novel interventions such as vaccines, traditional explanatory trials have struggled to provide definitive answers to time-sensitive questions for acutely ill patients with COVID-19. Pragmatic trials, which can increase efficiency by allowing some or all trial procedures to be embedded into clinical care, are increasingly proposed as a means to evaluate therapies that are in common clinical use. In this Personal View, we use two concurrently conducted COVID-19 trials of hydroxychloroquine (the US ORCHID trial and the UK RECOVERY trial) to contrast the effects of explanatory and pragmatic trial designs on trial conduct, trial results, and the care of patients managed outside of clinical trials. In view of the potential advantages and disadvantages of explanatory and pragmatic trial designs, we make recommendations for their optimal use in the evaluation of therapies in the acute care setting.

在进行试验以评估已经在临床上普遍使用的疗法时，会出现独特的挑战，包括由于试验疗法的广泛开放标签使用而难以招募患者，以及需要大样本量来检测小但具有临床意义的治疗效果。尽管在评估疫苗等新型干预措施的试验中取得了许多成功，但传统的解释性试验一直难以为 COVID-19 急性病患者的时间敏感问题提供明确的答案。实用性试验可以通过将部分或所有试验程序纳入临床护理来提高效率，越来越多地被提议作为一种评估临床常用疗法的方法。在这个个人观点中，我们使用两项同时进行的羟氯喹 COVID-19 试验（美国 ORCHID 试验和英国 RECOVERY 试验）来对比解释性和实用性试验设计对试验实施、试验结果和临床试验外管理的患者护理的影响。鉴于解释性和实用性试验设计的潜在优势和劣势，我们提出了在急性护理环境中评估治疗的最佳用途的建议。