Prevention is Better Than Cure: The Case for Clinical Trials of Therapeutic Cancer Vaccines in the Prophylactic Setting

Schematic representation of prostate cancer immunotherapy trial timelines. The timelines of screening, diagnostic, therapeutic and disease progression events are compared between the current paradigm of therapeutic prostate cancer immunotherapy trials and the proposed structure of studies designed to test the efficacy of prophylactic cancer vaccination. The current timeline shows the structure of cancer vaccine clinical trials performed to date in men with metastatic prostate cancer that is resistant to immunotherapy. It is contrasted with the proposed timeline of randomized, controlled clinical trials of cancer vaccines in the prophylactic setting. These would test the hypothesis that cancer immunotherapies administered prophylactically can increase the time to progression to adenocarcinoma in immunocompetent men who have precancerous PIN lesions. Standard prostate cancer therapies would be administered upon progression to adenocarcinoma; precisely when this occurs will depend on the efficacy of the prophylactic cancer vaccination strategy in delaying time to progression.