Results of Tyrosine Kinase Inhibitors (TKI) Therapy of Patients (Pts) with Chronic Myeloid Leukemia (CML) In Clinical Practice Analysed In the Frame of International Research Project EUTOS In Russian Federation

High efficiency of imatinib (IM) in CML therapy has been proven in clinical trials. However, the outcomes of CML treatment by IM in clinical practice are not covered in the literature.

To evaluate the results of CML treatment by TKI in clinical practice in the Russian Federation.

The data analysis from 28 administrative regions of theRussian Federation was performed. The selection of regions was based on the quality of the data from CML pts registry. 524 CML pts were included in this study. Inclusion criteria were: Ph/bcr-abl-positive CML diagnosed in 2002– 2006, age of pts ≥ 18 years (y), initiation of IM therapy ≤ 6 months (mo) from the date of diagnosis. Median (Me) age was 47(18 – 81) y, sex ratio (M/F (%)) 250/274 (48/52) pts, Me time from diagnosis to IM treatment was 2.4(0 – 6) mo. Pretreatment: Hydrea 398 (76%) pts; Mielosan 3 (0.5%) pts, chemotherapy 21(4%)pts, IFN-α 30 (5.7%) pts. Me follow-up since the beginning of CML treatment was 55.2 (1 – 108) mo (*6 pts have not data on the date of analysis). In Chronic Phase (CP) were 478 (91.2%) pts, in Accelerated Phase (AP) - 40 (7.6%) pts and in Blast Crisis (BC) - 6 (1.2%). Sokal risk stratification, %: 52 low (L)/22 intermediate (Int)/26 high(H) (78 pts with no baseline data. Statistical analysis was performed using a package SAS9.1.3.

427 (89%) from 478 CP CML pts were alive on May2011, 51(11%) pts were died. In this cohort of CP CML pts 5-year Overall Survival (OS) and Progression Free Survival (PFS) to AP/BC were 89% and 95% respectively (Me 56.4 (1 – 108) mo). The slow achievement of complete hematologic response (CHR) and complete cytogenetic response (CCyR) should be noted. On the IM therapy, 48% pts have achieved CHR by 3 mo only and 86% pts have achieved CHR by 12 mo (Me 3.2 (0.1 – 85) mo); CCyR at any time was achieved in 77% of pts, but by 12 mo – in only 40% of pts (Me 15 mo (0.7 – 75). There was no clear evidence of the dependence of OS rate from % of Ph’-positive cells in bone marrow after 6, 12, 18 and 36 mo were not received (p>0.5 in all cases). Analysis of molecular response (MR) was performed in 338 (70%) pts (not standardized rtPCR method): major MR was achieved in 241 (71%) pts (Me 42 (6–86) mo), complete MR - in 172 (50%) pts (Me 53(6–100) mo). OS by Sokal in pts with L and Int risk groups was identical and better than in pts with H, consistent with 90 and 83%, respectively (p=0.04). The probability of CCyR by Sokal were 85, 80 and 70% for the L, Int and H risk of disease progression, respectively (p=0,0002). IM therapy is still ongoing in 362 (85%) pts in doses 400/600/800mg/day-54%/33%/13%, respectively. 41(10%) pts were switched to 2^nd line TKI (25 pts to Nilotinib, 10 pts- Dasatinib, 6 pts-Bosutinib). In total, 51 (11%) pts died (21 pts with progression to AP/BC, 30pts with associated diseases).

The research program EUTOS enabled Russian hematologists to cooperate with an international research group (ELN) and this cooperation allows to improve the quality of CML treatment, monitoring MRD and data collection in the Russian CML registry. The analysis of data shows high rates of OS and PFS in CP CML, despite the delay of CHR and CCyR achievement. In clinical practice the low significanse of Sokal risk criteria and the absence of the influence of cytogenetic response achievement on OS was established that differ from clinical trial data and that may be due to a non-standardized approach to treatment and retrospective data collection.

Turkina:Novartis: Consultancy, Honoraria, Speakers Bureau; Bristol Myers Squibb: Consultancy, Honoraria, Speakers Bureau. Kulikov:Novartis: statistical tasks. Kutsev:Novartis: Research Funding, Speakers Bureau. Golenkov:Novartis: Speakers Bureau. Ivanova:Novartis: Honoraria, Speakers Bureau; Bristol Myers Squibb: Speakers Bureau. Pospelova:Novartis: Research Funding, Speakers Bureau; Bristol Myers Squibb: Speakers Bureau. Konstantinova:Novartis: Speakers Bureau. Lazareva:Novartis: Research Funding, Speakers Bureau, work with CML Registry. Khoroshko:Novartis: Speakers Bureau.