Statistical Criteria for Surrogate Endpoint and Applications : A Review

Surrogate endpoints, which represent a compromise in the conflict between measurability and clinical relevance of endpoints, have considerable advantage in rapid drug approvals compared to true endpoints in confirmatory clinical trials dealing with life-threatening diseases, such as cancer or AIDS. However, past experiences have shown the risk of relying too heavily on surrogate endpoints. In this paper, we review statistical criteria for evaluating surrogate endpoints and the past examples properly evaluated the surrogacy, taking into consideration relevant clinical and statistical issues.