Outcomes of Pregnancy During Immunotherapy Treatment for Cancer: Analysis of Clinical Trials Sponsored by the National Cancer Institute

Despite expanding indications for immunotherapeutic agents, there is limited understanding about their clinical effects on pregnancy outcomes. Generally, pregnant patients with cancer are excluded from clinical trials, and inadvertent pregnancies on trial result in patients being taken off because of concerns for fetal toxicity. To answer this question of pregnancy outcomes on immunotherapy-based trials, we performed a retrospective analysis of the National Cancer Institute (NCI) Cancer Therapy Evaluation Program (CTEP)-Adverse Event Reporting System for unexpected pregnancies during NCI-CTEP-sponsored immunotherapy clinical trials between 2011 and 2020. We identified nine female patients who had unexpected pregnancies, of whom seven chose to take their pregnancies to term. All seven pregnancies resulted in vaginal births of apparently normal infants. This is the first report of pregnancy outcomes in multiple female patients exposed to immunotherapy. Our data suggest the need for further research to better evaluate and define contraception recommendations during immunotherapy treatment for cancer.