Immunochemotherapy for life-threatening haematological malignancies in pregnancy: a systematic review of the literature and cross-sectional analysis of clinical trial eligibility

The management of potentially life-threatening malignancies in pregnancy is complicated by a lack of robust safety and efficacy evidence. This data shortage stems from a historical exclusion of women of childbearing potential from prospective clinical trials due to concerns around potential teratogenicity and toxicity of investigational agents. We conducted a systematic review of published data on immunochemotherapeutic treatment of life-threatening haematological malignancies in pregnancy between 2010 and 2022, and the maternal and neonatal outcomes. We then performed a cross-sectional observational study of clinical trial protocols on ClinicalTrials.gov, between 2016 and 2022, recruiting women of childbearing potential with potentially life-threatening haematological malignancies, collecting trial demographic data, and documenting whether pregnant or lactating women were explicitly excluded, along with the type and duration of contraception required for women of childbearing potential. We included 17 studies for analysis in our systematic review. A total of 595 women were treated with immunochemotherapy during pregnancy, with a median age of 29 years (range 14–48). Of these, 81 women (14%) were treated in the first trimester, and 514 (86%) were treated in the second and third trimesters collectively. In total, 68 trials for acute myeloid leukaemia, acute lymphocytic leukaemia, high-grade non-Hodgkin lymphoma, and Hodgkin lymphoma (40%, 26%, 21%, and 13%, respectively) were included in our ClinicalTrials.gov analysis. Most protocols (66 [97%]) explicitly excluded pregnant women, with 40 (69%) not providing a rationale for exclusion. The potential harm to the fetus from anti-cancer therapy has historically been given greater moral precedence than a pregnant woman's autonomy. This pattern is reflected in the lack of rigorous evidence for immunochemotherapy in pregnancy and a universal exclusion of pregnant and lactating women from clinical trial protocols in this study. Nonetheless, the administration of systemic chemotherapy in the second and third trimesters was not associated with an increased rate of congenital malformations or perinatal mortality in our systematic review cohort, with maternal outcomes broadly comparable to those of the non-pregnant population.