New concepts of biomarkers and clinical outcomes for therapeutic cancer vaccines in clinical trials

Aim: This study aimed to derive meaningful parameters for immune monitoring during cancer vaccine development by analysis of the literature. Methods: This retrospective study was based on analysis of clinical trials registered at ClinicalTrials.gov and published data available on PubMed. Results: The most common sample evaluated in immune monitoring was peripheral blood. All trials employed ELISA for detecting a humoral immune response; however, cellular immune assays were not used across trials. Most cellular immune assays failed to correlate with clinical outcome, although results of other methods did. Conclusion: Standardization of the cellular immune assays across trials is important for predicting the effects of therapeutic cancer vaccines when considering the reliability and characteristics of the methods. Currently, assays mostly target detection of T-cell function, such as proliferation and cytokine release; however, T-cell phenotype analysis in peripheral blood and/or tumor sites may also be considered in the future.