Effect of stopping tyrosine kinase inhibitors during pregnancy on disease status and reproductive outcomes among patients with chronic myeloid leukemia

Objective To explore the pregnancy outcome and disease status among patients with chronic myeloid leukemia (CML) treated with tyrosine kinase inhibitor (TKI) when they stopped TKI treatment during pregnancy. Methods The clinical characteristics, reproductive outcomes and disease status of the patients who stopped TKI due to pregnancy between November 2004 to November 2017 were retrospectively collected. Results A total of 14 CML patients in chronic phase (CML-CP), 12 patients were Sokal-low-risk. The median time of TKI treatment was 46.5 (15-123) months before the drug was stopped. The median age at the time of pregnancy was 29 (24-32) years. The median time of TKI exposure was 4 (0-9) weeks in 12 accidental pregnancies. Outcomes were available for 13 pregnancies, 9 cases (69.2%) delivered healthy babies, 1 case (7.7%) delivered polydactylia malformation baby, 3 cases (23.1%) had spontaneous abortion. The last one was still in pregnancy (no organ malformations were observed in color Doppler ultrasound). At the end of the follow up date, 10 children developed normal, the median age was 14 (0.7-65) months. Of the 14 patients who stopped TKI, 7 in complete molecular response (CMR), 3 in MR4 (BCR-ABLIS 10 000), 2 in major molecular response (MMR), 2 in complete cytogenetic response (CCyR). The median time of TKI discontinuation during pregnancy was 33.5 (4-40) weeks. At the end of pregnancy, 4 cases were in CMR, 4 in MR4, 1 in MMR and 4 in CCyR. No patients lost CCyR and complete hematologic remission. Conclusions During the treatment of imatinib and Nilotinib, unplanned pregnancy may have a normal infant, but may lead to spontaneous abortion and congenital malformations. Female of CML-CP who had sustained and stable MMR at least 24 months and Sokal-low-risk had higher safety factor discontinued TKI during pregnancy, but still had a risk of increasing tumor load, so monitored the level of BCR-ABL of peripheral blood monthly during pregnancy is necessary. Key words: Leukemia, myeloid, chronic, BCR-ABL positive; Imatinib; Nilotinib; Pregnancy