Stem cell therapeutics, as other therapeutic strategies, must surmount multiple requirements before reaching the phase of clinical trials. These requirements can be onerous in terms of time and funding and could, thereby, lead to abandonment of many promising therapeutics. One of these requirements is the perceived necessity of conducting large animal efficacy studies—especially pig studies—prior to initiating a clinical trial. The value of such a strategy, despite acceptance by experts, has never been demonstrated scientifically, raising the question of whether bias rather than evidence hampers the development of new therapeutic strategies. Of the questions facing investigators involved in developing new treatment strategies, one is common across disease disciplines and therapeutic approaches: What animal models should be used to determine whether the likelihood a therapeutic will be clinically successful is high enough to justify spending years of effort and tens, or even hundreds, of millions of dollars in clinical trials? A particularly vexing extension of this question is whether it is necessary to test efficacy in a large animal model prior to clinical trial launch. The purpose of this Viewpoint is to challenge the prevailing view, epitomized by the following quote: “Translational studies in large animal models (usually pigs) are rare because they are expensive, complex, time-consuming, technically demanding, slow, and usually not suitable for mechanistic investigations; nevertheless, because they are conducted in settings closer to the human situation than those found in rodent models, these studies are essential to justify the risks and costs of clinical trials.”1 This quote reflects current unofficial dogma that once efficacy of an intervention is established in mouse or other rodent models, efficacy needs confirmation in a large animal model—the most popular one being the pig.1–3 This is not a trivial conclusion because adequately powered pig studies are expensive from both …

中文翻译：

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在启动干细胞临床试验之前需要进行大型动物模型功效测试

与其他治疗策略一样，干细胞治疗必须在进入临床试验阶段之前超越多个需求。这些要求在时间和资金方面可能是繁重的，因此可能导致放弃许多有前途的疗法。这些要求之一是在开始临床试验之前进行大型动物功效研究（尤其是猪研究）的必要性。尽管得到专家的认可，这种策略的价值尚未得到科学证明，这就提出了一个问题，即偏见而不是证据是否会阻碍新治疗策略的发展。在研究人员开发新治疗策略时面临的问题中，一个在疾病学科和治疗方法中很常见：应该使用哪种动物模型来确定一种疗法在临床上成功的可能性是否足够高，足以证明花费数年的努力以及数以万计甚至数亿美元的临床试验是合理的？这个问题的一个特别令人烦恼的扩展是在临床试验启动之前是否有必要在大型动物模型中测试功效。该观点的目的是挑战主流观点，以下引述概括了这一观点：“大型动物模型（通常是猪）的转化研究很少，因为它们昂贵，复杂，耗时，技术要求高，缓慢且通常不适用于机械调查；但是，因为它们是在比啮齿动物模型更接近人类环境的环境中进行的，