Efficacy and safety of peginterferon alfa-2b for chronic myeloid leukemia and essential thrombocythemia during pregnancy

Abstract Background Myeloproliferative neoplasms during pregnancy increase the risk of maternal complications (including thrombosis and hemorrhage) as well as fetal complications (such as placental insufficiency, fetal growth restriction, and miscarriage). Treatment options for MPN during pregnancy are limited. Peginterferon alfa-2b (PEG-IFNα-2b), a long-acting interferon preparation, lacks sufficient data on its efficacy and safety in treating MPN during pregnancy. Method The clinical data of 24 patients with CML or ET during pregnancy treated with PEG-IFNα-2b from multiple centers were retrospectively collected and analyzed to evaluate its effectiveness (hematological response, pregnancy complications) and safety of both the mother and the baby (adverse events, pregnancy outcomes, growth and development of the offspring). Result A retrospective study enrolled 24 female MPN patients (14 with CML-CP and 10 with ET) who had received PEG-IFNα-2b during pregnancy. The median age was 27 years (range, 19-37) and PEG-IFNα-2b treatment was initiated at a median gestational week of 19 (range, 13-36) during pregnancy. The median number of PEG-IFNα-2b administered was 5 (range, 2-10). 23 patients (95.8%) achieved hematologic response before delivery, including 7 (29.2%) with complete hematologic response. PEG-IFNα-2b treatment significantly reduced white blood cell and platelet counts (p<0.001). The most common adverse event was fever accompanied by fatigue (50%), with all cases categorized as grade 1. All pregnancies resulted in healthy live births with no congenital anomalies or developmental delays observed in neonates. Conclusion Peginterferon alfa-2b for patients with CML or ET in the second and third trimesters of pregnancy has significant cytoreductive effects. Common adverse events include fever accompanied by fatigue, while no adverse effects on fetal development were observed, suggesting its potential safety in this population.