PB1947 COMPARISON OF EFFICACY AND SIDE EFFECTS OF SECONDLINE DASATINIB AND NILOTINIB THERAPIES IN PATIENTS WITH CHRONIC MYELOID LEUKEMIA IN CHRONIC PHASE RESISTANT OR INTOLERANT TO IMATINIB
Authors: I. Kaygusuz Atagunduz, F. Gecgel Arikan, T. Memis, T. Toptas, F. Yilmaz, Y. Ipek, T. Elibol, T. Tuglular
Journal: HemaSphere (2019)

Background: Twenty to 30% of imatinib-treated CML patients in the chronic phase of the disease may necessitate a switch to second-line therapies due to toxicity or lack of efficacy. In clinical trials, nilotinib and dasatinib have been shown to be effective and safe in second-line treatment in these patients. There is no clinical study comparing the efficacy and side-effect profile of nilotinib and dasatinib in second-line treatment. Real life data on this subject is also limited. Aims: The aim of this study was to compare the efficacy and side effects of two tyrosine kinase inhibitors in patients with chronic myeloid leukemia in chronic phase (CML-CP) who are resistant or Intolerant to Imatinib. Methods: We retrospectively analyzed a database of consecutive CML-CP patients treated with either nilotinib or dasatinib in the second line at our hematology outpatient clinic between January 2003 and July 2018. Results: Forty-one patients received dasatinib and 36 patients received nilotinib treatment. Median follow-up period was 30.0 months in both groups. The rate of ≥ major molecular response was 100% in patients receiving nilotinib treatment and 87.5% in patients receiving dasatinib. However, the difference was not statistically significant. Treatment discontinuation was more frequent in patients receiving dasatinib than in nilotinib group (20 (48.8%) patients in dasatinib, 13 (36.1%) patients in the nilotinib group respectively p = 0.11). The reasons for discontinuation of treatment were loss of response (13%), hematological toxicity (2%), non-hematological toxicity (19%) in nilotinib group and progression (2%), lack of achievement of response (7%), loss of response (4%), hematological toxicity (4%), non-hematological toxicity (24%) in dasatinib group. The most common side effects were skin rash (11%) in nilotinib treated patients and pleural effusion (26%) in the dasatinib group. Treatment failure was detected in 5 (13%) patients with nilotinib and 8 (19.5%) patients with dasatinib (p = 0.11). Overall, 2 patients (5%) from the second-line nilotinib treatment group had died at the time of analysis. One patient died of a cause not related to the disease, and one patient died of grade 4 pancreatitis. One patient (2%) had died in the dasatinib group because of a cause not related to the disease. The median event-free survival was 63 months in patients receiving nilotinib and 75 months in patients receiving dasatinib. The difference was not statistically significant (p = 0,35). Median OS was not reached in both groups. Summary/Conclusion: As shown in clinical studies, nilotinib and dasatinib were found to be highly effective and safe in the second line treatment of CML-CP with high response rates in our daily routine hematology practice. In our patient group, it was determined that both drugs showed similar activity. There is a need for larger studies involving more patients to achieve real-life data.