Targeted agents for cancer treatment during pregnancy

The last decade has witnessed important advances in the field of managing cancer during pregnancy. However, still limited data is available on the safety of administering targeted agents in pregnant cancer patients. Given the increasing use of targeted agents in clinical practice, it is becoming vital to properly understand how far they can be used in a pregnant patient without compromising the outcome of the fetus. Unlike chemotherapy, monoclonal antibodies are large molecules that require active transport via the placenta to reach the fetus. On the other hand, similarly to chemotherapy, small molecules like tyrosine kinase inhibitors (TKIs) can cross the placenta throughout the pregnancy period. The majority of targeted agents have worrying preclinical data discouraging their use during pregnancy. Multi-TKIs are of particular concern given their potential interference with other vital physiological functions that could be necessary in fetal development. Yet this does not mean that all targeted agents should be avoided completely during pregnancy. The current review provides a critical evaluation on all targeted agents that are currently in clinical use and provides a guide in order to help clinicians counseling their pregnant cancer patients.