Outcomes of pregnancy in patients with chronic myeloid leukemia in the era of tyrosine kinase inhibitors.

Background: Young female patients with chronic myeloid leukemia (CML) often face challenges becoming pregnant due to the teratogenicity of tyrosine kinase inhibitors (TKIs).

Methods: The authors conducted a nationwide survey of female patients with CML who experienced pregnancy between 2002 and 2020.

Results: Information for 70 pregnancies in 49 patients was obtained. There were three types of pregnancies: CML onset during pregnancy (n = 9), unplanned pregnancy mostly during treatment with a TKI (n = 25), and planned pregnancy during treatment-free remission (TFR) or treatment with interferon-alpha (IFN-α) (n = 36). The median duration from CML diagnosis to pregnancy in patients with planned pregnancy was significantly longer than that in patients with unplanned pregnancy (10.6 years vs. 4.1 years, p < .001). In 48 pregnancies that resulted in childbirth, TFR and treatment with IFN-α were chosen in 26 and 17 pregnancies, respectively. Sustained major or deeper molecular response was observed in 18 of 26 pregnancies with TFR. The patients who fulfilled the requirements for TKI therapy discontinuation by European LeukemiaNet recommendations achieved a TFR rate of 77% in pregnancy. Treatment with IFN-α might be effective for patients who are in complete cytogenetic response or deeper response (response rate, 76%).

Conclusion: Pregnancy by TFR or treatment with IFN-α could be a safe and feasible way for patients with CML. However, a substantial duration of treatment with a TKI before conception may be needed for planned pregnancy. Planning and evaluation for pregnancy should be considered at the time of CML onset for female patients with childbearing potential.