In the last two decades, single-arm trials (SATs) have been effectively used to study anticancer therapies in well-defined patient populations using durable response rates as an objective and interpretable clinical endpoints. With a growing trend of regulatory accelerated approval (AA) requiring randomized controlled trials (RCTs), some confusions have arisen about the roles of SATs in AA. This paper is intended to elucidate conditions under which an SAT may be considered reasonable for AA. Specifically, the paper describes (1) two necessary conditions for designing an SAT, (2) three sufficient conditions that help either optimize the study design or interpret the study results, (3) four conditions that demonstrate substantial evidence of clinical benefits of the drug, and (4) a plan of a confirmatory RCT to verify the clinical benefits. Some further considerations are discussed to help design a scientifically sound SAT and communicate with regulatory agencies. Conditions presented in this paper may serve as a set of references for sponsors using SATs for regulatory decision.

翻译：在过去的二十年中，单臂试验（SATs）已被有效用于在明确界定的患者群体中研究抗癌疗法，其以可解释的客观临床终点——持久应答率作为评价指标。随着监管机构日益要求通过随机对照试验（RCTs）获取加速批准（AA），关于SATs在AA中作用的困惑逐渐浮现。本文旨在阐明在哪些条件下SATs可被视为适用于AA的合理选择。具体而言，本文描述了：（1）设计SAT的两项必要条件；（2）有助于优化研究设计或解读研究结果的三项充分条件；（3）证明药物临床获益实质性证据的四项条件；（4）验证临床获益的确证性RCT计划。此外，本文还探讨了进一步考量因素，以帮助设计科学合理的SAT并与监管机构进行沟通。本文提出的条件可作为申办方利用SAT进行监管决策的参考依据。