The assurance of a future clinical trial is a key quantitative tool for decision-making in drug development. It is derived from prior knowledge (Bayesian approach) about the clinical endpoint of interest, typically from previous clinical trials. In this paper, we examine assurance in the specific context of vaccine development, where early development (Phase 2) is often based on immunological endpoints (e.g., antibody levels), while the confirmatory trial (Phase 3) is based on the clinical endpoint (very large sample sizes and long follow-up). Our proposal is to use the Phase 2 vaccine efficacy predicted by the immunological endpoint (using a model estimated from epidemiological studies) as prior information for the calculation of the assurance.

中文翻译：

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基于免疫反应的疫苗有效性临床试验设计保证

未来临床试验的保证是药物开发决策的关键定量工具。它来源于有关感兴趣的临床终点的先验知识（贝叶斯方法），通常来自以前的临床试验。在本文中，我们研究了疫苗开发特定背景下的保证，其中早期开发（第 2 阶段）通常基于免疫学终点（例如抗体水平），而验证性试验（第 3 阶段）基于临床终点（非常大的样本量和长期的随访）。我们的建议是使用免疫终点预测的 2 期疫苗效力（使用流行病学研究估计的模型）作为计算保证的先验信息。