Immune checkpoint inhibitor administration during pregnancy: a case series

Immune checkpoint inhibitors have been widely implemented in current clinical practice. Although cancer occurs in ∼1 out of 1000 pregnancies, treatment remains challenging. Until now, limited data exist regarding immunotherapy administration during pregnancy. This systemic review aims to synthesize all available data from immunotherapy administration in pregnant women and evaluate the efficacy and safety of immunotherapy during pregnancy.

Eligible studies were identified by a search of the PubMed Medline database and Food and Drug Administration Adverse Events Reporting System Public Dashboard for the period 1 January 2000 to 1 April 2021; the algorithm consisted of a predefined combination of the words 'immunotherapy', 'cancer' and 'pregnancy'. PRISMA guidelines were applied in this study.

Overall, seven articles (seven pregnancies, nine neonates) were retrieved. The mean duration of immunotherapy administration was 9.8 weeks [standard deviation (SD): 11.27; median: 7.0; range: 1-32]. In all cases specified, melanoma was the malignancy reported. The mean gestational age at delivery was 30.4 weeks (SD: 5.03; median: 32.0; range: 24-38), whereas the mean weight of neonates at delivery was 1267 g (SD: 412.0; median: 1400; range: 590-1701). Only one neonate was born term at 38 weeks of pregnancy (11.1%; 1/9). Complications during pregnancy were observed in 71.4% of cases: intrauterine growth restriction (three cases), HELLP syndrome (hemolysis, elevated liver enzymes, low platelet count) (one case), placental insufficiency (one case) and low fetal heart rate (one case). The mean progression-free survival and overall survival were 16.0 and 25.2 months, respectively.

The administration of immune checkpoint inhibitors during pregnancy is associated with increased incidence of pregnancy complications, prematurity and low birth weight. The administration of these regimens is not recommended during gestation. Whenever applied, close monitoring of the mother and the fetus is required.