LAUSR

Abstract Background The prognosis of CML has dramatically improved with the introduction of imatinib. Patients diagnosed in chronic phase can live almost as long time as healthy people. However, adequate strategy of pregnancy under TKI treatment has not been established. Case report 31-year-old-female was introduced to us because of leukocytosis. She was diagnosed as CML CP. We let her visit OB-GYN clinic with her partner to preserve a fertilized egg. After its preservation, we initiated dasatinib as her first-line-treatment. She achieved CHR in a month, CCyR in 3 months, and MMR in 10 months. Therefore, her clinical course could be evaluated as optimal. However, she strongly requested to have a baby early. We switched her TKI from dasatinib to nilotinib for deeper molecular response. 5 months later, she accidentally became pregnant. She stopped taking nilotinib at 5th week of her pregnancy and selected to give a birth even with a risk: her disease had not reached DMR. Considering her disease status, it was impossible to stop all the treatment, so we initiated IFN-alpha, which was known not to cross the placenta. She did not experience any adverse event with it, and successfully gave birth to a 2500g baby without any abnormality. We checked MRD once in 3 months, her disease kept MR4.0 all the pregnancy period.[Discussion] Discontinuation of TKIs is under trial now. According to the JSH guideline, significant treatment duration (over 3 years) and DMR more than MR4.5 over 2 years are necessary conditions for planning pregnancy. But 2 and more years could be said too long for young women who hope for children. In this case, we switched TKIs for achieving DMR as early as possible. But unexpected pregnancy occurred in MMR. As a result, she gave a birth without any major event under IFN-alpha therapy. Conclusion The IFN-alpha therapy for pregnant female achieved safe and normal delivery.