PB1942 DOES STEPWISE DOSE ESCALATION METHOD OF NILOTINIB FOR CML IMPROVE MR4.5 AND TREATMENT FREE REMISSION?

Background: Every TKI has it's unique adverse events (AEs) and AEs drive therapeutic outcome down in patient with CML‐CP. Treatment completion rate(TCR), complete molecular response(MR4.5), and treatment free remission(TFR) were examined. Aims: We conducted this study aiming at improving TCR, MR4.5, and TFR by stepwise dose escalation method of nilotinib. Methods: TCR, MR4.5, and TFR (6, 12, and 18 months) were examined by stepwise dose escalation method of nilotinib (4‐Stepwise method, i.e., 150mg‐14day, 300mg‐14day, 450mg‐14day, 600mg‐2years) in imatinib experienced or newly diagnosed patient with CML‐CP. Results: 25 cases were enrolled in this study and all patient were received this method. Consequently, all patients achieved 600 mg, TCR was 100% by the method. 22 cases (88%) achieved MR4.5, and all of them transferred to treatment discontinuation phase. 7 cases out of 22 lost MMR in non‐treatment period, and all of them remained in the CP phase and were administered nilotinib again. TFR at 6, 12, 18 months were 86%(19/22), 75%(15/20), 79%(15/19), respectively. NK cell activity at before treatment, one of important biomarker, showed a significant difference between not achieved MR4.5 group and achieved MR4.5 group(P = 0.04). Summary/Conclusion: In this study, our stepwise dose escalation method of nilotinib (4‐Stepwise method, i.e., 150mg‐14day, 300mg‐14day, 450mg‐14day, 600mg‐2years) will make good use of improving therapeutic outcome. TCR was 100%. 22 out of 25 cases (88%) achieved MR4.5, and all of them were transferred to treatment discontinuation phase. 7 out of 22 cases lost MMR, TFR at 6, 12, 18 months were 86%(19/22), 75%(15/20), 79%(15/19), respectively. NK cell activity at before treatment, showed a significant difference between not achieved MR4.5 group and achieved MR4.5 group(P = 0.04).