PF422 THE LONG‐TERM TREATMENT RESULTS OF THE MULTICENTER EUTOS ELN POPULATION‐BASED STUDY (EUTOS‐PBS) IN PATIENTS WITH CHRONIC MYELOID LEUKEMIA IN RUSSIAN FEDERATION
Authors: O. Lazareva, A. Turkina, E. Chelysheva, O. Shukhov, A. Kulikovsky, M. Galayko, O. Senderova, V. Pepeliaeva, S. Meresiy, A. Luchinin, G. Milutina, L. Gavrilova, L. Avdeeva, E. Dasheeva, O. Vinogradova, S. Kulikov
Journal: HemaSphere (2019)

Background: The data of 2904 adult patients (pts) with newly diagnosed chronic myeloid leukemia (CML) from 20 European countries were included into the multicenter EUTOS ELN population‐based Study (EUTOS PBS) from 2008 to December 2012 (Hoffman V et al. 2016). Russia took part in the EUTOS PBS and included 6.8% of the total number of pts. The EUTOS PBS in Russian Federation was prolonged and the results were updated at a long‐term follow‐up. Aims: To evaluate the long‐term results of treatment in pts with newly diagnosed CML in EUTOS PBS in Russia. Methods: The analyzed cohort of 197 pts (18 years) with Ph’+ / BCR‐ABL1 +CML diagnosed in period 10/01/2009 ‐ 31/12/2012 from 6 regions of Russia was included into EUTOS PBS. CML was diagnosed in chronic phase (CP), accelerated phase (AP) and blast crisis (BC) in93,4%, 6% and 0,6%pts respectively. The ELTS low, intermediate and high score(n = 179)was in 86 (48%), 50 (28%) and 43 (24%) pts accordingly. Median (Me) age was 50 (18–82) years, the male/female ratio was equal. The overall survival (OS) considering CML phase, cumulative incidence (CI) of deaths depending on death reasons was analysed. The CI of complete cytogenetic response (CCyR) and major molecular response (MMR) was evaluated. All calculations were done using the SAS Version 9.4 package of procedures program. Results: Me follow‐up in the Russian part of EUTOS PBS was 69 (0,7 – 96) months (mo). Imatinib (IM) and 2 nd generation tyrosine kinase inhibitors (TKI2) were used as 1 st line therapy in 97% and 3% pts accordingly. The 5 years CI of CCyR and MMR at the 1 st line TKI therapy was 83% and 67% accordingly. The switch to the 2 nd and 3 rd line of TKI2 therapy was in 22 (12%) of 193 pts, the main reason was IM failure. The OS by 5, 6 and 7 years was 80% (95% CI 72% ‐ 86%), 78% (95% CI 65% ‐ 80%) and 73% (95% CI 65% ‐ 80%) respectively in total cohort ( p &lt; 0,001). The OS of pts with low and high ELTS score was 88% and 56% ( p &lt; 0,0023) respectively by the 80 mo of follow‐up. The 5‐year OS in pts with AP+BC phase was 39%. In total 47 (23,8%) pts died during the whole observation period. The largest number of deaths was observed in the 1 st year after the CML diagnosis: 17 (36%) of 47 cases. The death reasons were as follows: 1) progression of CML to AP/BC in 20 (43%) pts, 2) death in remission (pts with CCyR and /or MMR within 6 months before death) in 5 (11%) pts, 3) death without progression to AP/BC but with signs of leukemia and without CCyR in 22 (46%) patients. The 5 years CI of death from all reasons was 20%, CI of CML‐related and CML non‐related death at 5 th year was 18% and 11% respectively (figure1). Summary/Conclusion: In general, the results of therapy in CML pts of the Russian non‐selected population sample were comparable to the data of the whole European cohort. A higher proportion of pts with ELTS high ELTS scoreand a lower proportion of pts switched to 2 nd /3 rd line TKI therapy in comparison with Europe was identified. These issues could have an impact on the number of CML‐related deaths and their high proportion in the 1 st year of therapy. Therefore, the early therapy interventions within the 1 st year of therapy in CML pts are apparently important for the long‐term treatment results. image