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Russia took part in the multicenter population-based study (Europe) and included 6.8% adult patients with newly diagnosed chronic myeloid leukemia (CML). The objective of this study was to analyze the mortality in the Russian cohort of patients with newly diagnosed CML in the EUTOS PBS observational study.The analyzed cohort consisted of 197 patients (18 years) with Ph+/BCR-ABL1+ CML diagnosed in the period from October 1, 2009 through December 31, 2012 from 6 regions of Russia. The distribution of the phases of CML were: chronic phase (CP), 93.4% and accelerated phase (AP) + blast crisis (BC), 6% + 0.6%. The median age was 50 years (range, 18-82 years); the male/female ratio was equal.The overall survival (OS) at 5, 6, and 7 years was 80% (95% confidence interval [CI], 72%-86%), 78% (95% CI, 65%-80%), and 73% (95% CI, 65%-80%), respectively (P .001). The 5-year OS in patients with AP and BC was 39%. In Russia, the study was prolonged, with a median follow-up of 77 months (range, 0.7-108 months): 141 (71.5%) patients were alive, 47 (24%) patients died, and the status of 9 (4.5%) patients is was unknown. Forty-seven (23.8%) patients died during the follow-up period. The largest number of deaths was observed in the first year after the CML diagnosis: 17 (36%) of 47 cases, 3 of 17 died refusing the CML treatment. At the seventh year of CML therapy, 1 patient died after allogenic hematopoietic stem cell transplantation. The causes of death were: (1) progression of CML to AP/BC in 20 (43%) patients; (2) death in remission in 5 (11%) patients with complete cytogenetic response (CCyR) and/or major molecular response; and (3) death without progression to AP/BC but with signs of leukemia in 22 (46%) patients. The 5-year cumulative incidence of death from all reasons was 20%; the cumulative incidence of CML-related and non-CML-related death at the fifth year was 18% and 11%, respectively.In general, the results of treatment in the Russian population sample of non-selected patients with CML were comparable with the data of the total European cohort. The CML-related deaths prevailed in the first year of CML therapy. The appropriate monitoring and therapy interventions during the first year of CML treatment are apparently important for the long-term treatment results.

T-cell acute lymphoblastic leukemia (T-ALL) is a rare disease usually treated with intensive, high-dose consolidation chemotherapy followed by an allotransplant in a substantial number of patients. The data of the RALL-2009 study on 125 adult T-ALL patients suggest that similar total chemotherapy doses given less intensively over a longer interval without interruptions and with an auto- rather than an allotransplant produce outcomes like current more intensive protocols and an allotransplant: 9-year cumulative incidence of relapse (CIR), leukemia-free survival (LFS), and survival were 24% (95% CI 16–33%), 70% (95% CI 59–79%) and 62% (95% CI 51–72%). In a landmark analysis, subjects achieving a complete remission and receiving an autotransplant had a lower 9-year CIR (9% [95% CI 2–22%] vs. 29% [95% CI 16–43%]; p = 0.0076) and better LFS (91% [95% CI 79–98%] vs. 58% [95% CI 41–74%]; p = 0.0009) and survival (92% [95% CI 77–99%] vs. 60% [95% CI 44–77%]; p = 0.001) compared with subjects not receiving an autotransplant. In a multivariate analysis, white blood cells ≥100 × 109/L at study entry were significantly associated with worse LFS (HR = 2.842 [95% CI 1.131–7.143]; p = 0.0263) and survival (HR = 6.085 [95% CI 1.918–19.3]; p = 0.0022) because of more early deaths (HR = 2.42 [95% CI 1.04–5.67]; p = 0.041). Receiving an autotransplant correlated with a lower CIR (HR = 0.23 [95% CI 0.07–0.73]; p = 0.0136) and better LFS (HR = 0.27 [95% CI 0.08–0.85]; p = 0.0256) and survival (HR = 0.158 [95% CI 0.045–0.550]; p = 0.0037).

Context Molecular factors to determine the prognosis for primary mediastinal B-cell lymphoma (PMBCL) are not described yet. In this regard, the loss of heterozygosity (LOH) in STR loci and elevated microsatellite alteration at selected tetranucleotides (EMAST) in the tumor genome are of interest. Objective To analyze the frequency of LOH and EMAST in tumor cells of PMBCL patients at diagnosis and to check possible association with disease features. Design STR profiles of the DNA of tumor cells were analyzed in a cohort of 72 PMBCL patients undergoing EPOCH regimen treatment at the National Research Center for Hematology (Moscow, Russia). Setting DNA was isolated from tumor biopsy samples taken at diagnosis. Control DNA samples were taken from the blood of patients in complete remission or from the buccal epithelium. STR profiles for LOH and EMAST analysis were assessed by PCR with the COrDIS Plus multiplex kit for amplification of 19 STR markers and amelogenin loci (Gordiz Ltd, Russia). The fragment analysis was performed on an ABI3130 Genetic Analyzer. Patients Inclusion criterion: de novo-diagnosed PMBCL patients. Exclusion criterion: pre-treatment. Main Outcomes Measures Progression-free survival (PFS) and overall survival (OS) at 24 months from diagnosis were used to assess the independent impact of genetic instability as a risk factor. Results LOH was detected in 37 of 72 patients (51.4%). EMAST was found in 40 patients (55.5%); 24 had a combination of EMAST with LOH. For all EMAST-positive patients, the number of involved loci was no more than 4 out of 19 (EMAST-low, less than one-third of the panel of microsatellite markers). It was shown that OS and PFS were the highest in patients with a stable STR tumor profile. Conclusions STR profiling of PMBCL tumor genome revealed LOHs associated with deletions or uniparental disomy and detected EMAST attributed to failure of DNA mismatch repair. The high incidence of LOH and EMAST in PMBCL can be associated with standard therapy failure in a significant number of patients. Funding This study was supported by Rakfond grant 2/2020.

Context: The independent influence of pre-transplant MRD status on the results of allogeneic hematopoietic stem cell transplantation (allo-HSCT) is now being widely reported. The genetic and immunophenotypic diversity of AML is a problem for monitoring MRD in daily clinical practice. The most widely used methods for assessing MRD are multiparametric flow cytometry (MFC) and PCR. Objective: To assess the impact of pre-transplant MRD status determined by MFC or PCR on the long-term results of allo-HSCT. Patients and Methods: The study included 106 patients with AML in the 1st CR who underwent allo-HSCT in our center from September 2015 to December 2020. The median follow-up was 19.5 (1–50) months. Eleven-color MFC was performed on bone marrow samples obtained before allo-HSCT. In 46 out of 106 patients who had molecular markers (NPM1, FLT3, RUNX1-RUNX1T1, MLL, or CBFβ-MYH11), the MRD status was determined using PCR also. Cox proportional hazards models were used to assess the influence of various independent factors on the probability of relapse (PR). The factors included in the model were ELN risk, donor type, conditioning regimen, graft source, pre-transplant MRD status, and age. The probabilities of DFS and relapse were estimated using the Kaplan-Meier method. Results: Out of 106 patients, 22 were identified as MRD+ MFC, 84 patients were MRD- MFC, 16 patients were MRD+ PCR, and 30 patients were MRD- PCR. Statistical analysis revealed significant differences between MRD+ and MRD- patients, regardless of the research method: patients with MRD+ status had the worst DFS (MFC: 24% versus 64%, p 40 y (HR=7.006) were independent factors influencing the probability of relapse. Conclusions: MRD, regardless of whether it is determined by MFC or PCR, ELN risk, and older age are independent predictors of disease recurrence risk. The study of MRD in AML patients before allo-HSCT can be used to stratify the risk of allo-HSCT and identify patients who need prophylactic post-transplant therapy to prevent disease relapse.

Context: Loss of heterozygosity (LOH) in some STR loci established for de novo-diagnosed ALL could be used as a prognostic factor for possible poor clinical outcomes. Objective: To identify LOH in the blast cells of patients with B- and T-ALL at diagnosis and to analyze therapy outcomes according to LOH status. Design: This study includes an analysis of the STR profiles in the DNA of tumor cells for a cohort of 87 patients with de novo-diagnosed Ph-negative ALL (40 B-ALL, 44 T-ALL, 3 biphenotypic ALL) and a statistical evaluation of LOH as a possible risk factor for B- and T-ALL. All patients were treated according to the “RALL-2016” regimen at the National Research Center for Hematology (Moscow, Russia). Setting: DNA was isolated from patient bone marrow samples taken at diagnosis. Control DNA samples were taken from the blood of patients in complete remission and/or from a buccal swab. STR profiles were assessed by PCR with the COrDIS Plus multiplex kit (Gordiz Ltd, Russia). LOH in tumor DNA was verified by chromosomal microarray (CMA CytoScanHD). Patients: Inclusion criteria: de novo-diagnosed Ph-negative ALL patients, 18-55 years old, intermediate-risk group without MLL translocation t(4;11)(q21;q23), and treatment by RALL-2016 protocol. Exclusion criteria: patients older than 55 years, MLL translocation t(4;11)(q21;q23), and pretreatment. Main Outcome Measures: A multivariate survival analysis was used to assess the independent impact of the LOH as a risk factor. Overall survival (OS) was chosen as the primary endpoint. Results: Of the 87 patients, 21 were characterized with LOH in certain STR loci (24%). The most common was 9p LOH (12 patients). 12p LOH was detected in 8 patients. According to OS analysis, LOH 12p seems to be a marker of a favorable prognosis. For B-ALL patients, LOH (excepting 12p LOH) was an independent risk factor (OS hazard ratio 3.89, log-rank P-value 0.0395). For T-ALL patients, the OS hazard ratio was 0.59 (log-rank P-value 0.62). Conclusions: We have found a statistically significant association of clinical failures with the LOH in STR loci measured at the onset of B-ALL but not T-ALL. Funding: This study was supported by Rakfond grant 5/2019

Context: Loss of heterozygosity (LOH) in STR loci, elevated microsatellite alteration at selected tetranucleotides (EMAST) and instability of mononucleotide tandem repeats (MSI - microsatellite instability) are intrinsic features of diverse tumor cells. For primary mediastinal B-cell lymphoma (PMBCL) these molecular factors to determine the prognosis of the disease have not been described yet. Objective: To analyze the frequency of LOH, EMAST, and MSI in tumor cells of PMBCL patients at diagnosis and to check possible association with disease features. Design: STR profiles of the DNA of tumor cells were analyzed on a cohort of 36 PMBCL patients undergoing treatment at the National Research Center for Hematology (Moscow, Russia). Setting: DNA was isolated from tumor biopsy samples taken at diagnosis. Control DNA samples were taken from the blood of patients in complete remission or from the buccal epithelium. STR-profiles for LOH and EMAST analysis were assessed by PCR with COrDIS Plus multiplex kit for amplification of 19 STR-markers and amelogenin loci (Gordiz Ltd, Russia). COrDIS MSI (BAT-25, BAT-26, NR-21, NR-24 and NR-27) kit was used for MSI testing. The fragment analysis was performed on ABI3130 Genetic Analyzer. Patients: Inclusion criteria: de novo diagnosed PMBCL patients. There were 10 males and 26 females, the median age at presentation was 30 years (range 21–61). Main outcome measures: Progression-free survival (PFS) and overall survival (OS) at 24 months from diagnosis were used to assess the independent impact of the genetic instability as a risk factor. Results: LOH was revealed in 21 out of 36 patients (58%). EMAST was found in 18 patients (50%); in 12 of them EMAST was accompanied by LOH, and in one by MSI. MSI was found in three patients only. OS and PFS were highest in the group with stable STR profile of a tumor, but not formally significant because of the small sample size. Conclusions: The high incidence of LOH and EMAST in PMBCL can cause standard therapy failure in a significant number of patients. EMAST as a variant of microsatellite instability might be useful for further consideration as a predictor of response to checkpoint inhibitor therapy.

We report the data on 15 women who presented with Ph-negative acute lymphoblastic leukemia (ALL) between Jan 2009 until Dec 2016 and who were treated on the prospective multicenter RALL-2009 clinical trial. A comparison of their outcome was made with 129 non-pregnant females who entered the study and were treated by the same schedule. 10-years OS for pregnant and non-pregnant women was 58.6 % (29.6 %-85.0 %) and 43.3 % (32.1 %-58.8 %), DFS was 46 % (15.2 %-78.8 %) and 51 % (39.7 %-64.6 %); probability of relapse was 49 % (16.6 %-83.3 %) and 40.3 % (27.3 %-53.4 %), respectively. Twelve born during the study children are well and alive with a median age 5 years 2 months (2 years - 9 years). Though small, our study has shown some specific features of ALL diagnosed during pregnancy (more T-cell ALL, higher initial WBC, later responses) and has shown that the long-term outcome of women with ALL treated while pregnant is equivalent to female control patients treated on the same protocol.

Context Loss of heterozygosity (LOH) was described for many malignancies including leukemia. Previously, we noted LOH at STR loci is especially frequent for relapsed ALL patients. LOH established for de novo-diagnosed ALL could be used as a prognostic factor for possible poor clinical outcome. Objective To identify LOH in the blast cells of the patients with ALL at diagnosis and to analyze therapy outcomes relative to patients without LOH. Design This study includes an analysis of the STR profiles of the DNA of tumor cells from a cohort of 47 patients with de novo-diagnosed Ph-negative ALL undergoing treatment according to the “RALL-2016” regimen at the National Research Center for Hematology (Moscow, Russia) and statistical evaluation of LOH as a possible risk factor. Patients with the LOH at the short arm of 12 chromosome (12pLOH) are excluded from risk group because 12p LOH is not associated with worse outcome according to many publications. Setting DNA was isolated from patient bone marrow samples taken at diagnosis. Control DNA samples were taken from the blood of patients in complete remission and/or from the buccal swab. STR profiles were assessed by PCR with COrDIS Plus multiplex kit for amplification of 19 polymorphic STR-markers and amelogenin loci (Gordiz Ltd, Russia). Patients Inclusion criteria: de novo-diagnosed Ph-negative ALL patients, 18–55 years old, intermediate risk group without MLL translocation t(4;11)(q21;q23), and treatment by RALL-2016 protocol. Exclusion criteria: patients older than 55 years, MLL translocation t(4;11)(q21;q23), and pre-treatment. Main outcome measures A multivariate survival analysis was used to assess the independent impact of the LOH as a risk factor. Overall survival (OS) was chosen as primary endpoint. Results Of the 47 patients, 10 were found with LOH in the certain STR loci (21%). 12p LOH was detected in four patients. OS of patients with other LOH was significantly lower than for patients without LOH (HR=6.02 (95% CI: 1.66–21.78), p=0.0019). Conclusions We have found a statistically significant association of clinical failures with the LOH in STR loci (except 12p LOH) measured at the onset of ALL. Funding This study was supported by Rakfond grant 5/2019

Introduction Duration of treatment with tyrosine kinase inhibitors (TKI) is an important favorable prognostic factor for treatment-free remission (TFR) and deep molecular response (DMR) in patients (pts) with chronic myeloid leukemia (CML). Aim To analyze the impact of first-line treatment duration with imatinib and 2G TKI on molecular relapse-free survival (MRFS) in CML pts with sustained DMR. Patients and methods In total, 174 CML pts in chronic phase with ≥3 years treatment duration and sustained DMR (MR4-MR5, BCR-ABL IS 0.1%). Median (Me) age of pts was 43 (range 21-86) years; 39% were males. Me TKI treatment duration was 86 months (IQR 57-125 mo), Me DMR duration was 45 (IQR 29-66 mo). Imatinib, 2G TKI in first-line and 2G TKI in second-line were discontinued in 116 (66.7%), 15(8.6%) (11 nilotinib, 3 dasatinib, 1 bosutinib) and 43 (24.7%) (34 nilotinib, 9 dasatinib) pts respectively. Results Me follow-up time after treatment cessation was 33 months (range 1-133). MRFS at 6, 12, 24 and 36 months was 62% (CI: 55-70%), 53% (CI: 45-60%), 50% (CI: 42-57%) and 48% (CI: 40-56%) respectively. Treatment duration and MR4.5 vs MR4 were significant for MRFS both in univariate (p=0.009 and p=0.015) and multivariate analysis (p=0.017 and p=0.037). No difference in 36 months MRFS was observed for imatinib (47% (CI: 42-60%)), first-line 2G TKI (59% (CI: 33-84%) p=0.58) and second-line 2G TKI (47% (CI: 32-63%) p=0.97) groups. However, significantly shorter treatment duration was observed in first-line 2G TKI group (Me=44 mo (IQR 40-52 mo)) vs imatinib (Me=93 mo (IQR 69-127 mo)), p Conclusion The 2G TKI as a first-line seem to be an effective option to reduce the treatment duration before TFR in CML pts although MRFS rate was not significantly improved in our study.

Introduction: Most surrogate endpoints are based on periodical measurement and the assessment of event time uses data censored by both sides. Kaplan-Maier (KM) estimators are calculated from right censored data and as result they are biased and sensitive to irregularity in measurements. High rate of missing data and irregularity is a common problem for registries. Interval Censorship Estimators (ICE) are relative complex but more reliable and robust than KM. Cytogenetic response is a major prognostic factor for long-term results of therapy of chronic myeloid leukemia (CML) and is often used as surrogate endpoint. The challenge of ICE usage instead of KM’s for cytogenetic response estimation is illustrated on real data from the registry of patients with CML. Methods and data source: We compare data in 2 studies of similar population of CML patients. The studies are distinguished by the design and completeness of data. First one is retrospective, second is prospective controlled registry population study. For evaluation of time to event characteristics two estimators were used and compared: classical KM estimators and ICE estimators based on Turnbul’s algorithm, realized as SAS Macro [1]. The EUropean Treatment Outcome Study (EUTOS) is a registry based international investigation started in June 2007 running for 3 years. The aim is to study the epidemiology of CML. The first part of the study is OUT Study section (EUTOS-OSP) with retrospectively collect data form patients who are not included into the local or international clinical trials. The second part of EUTOS study is online registry so called Population Based Sections (PBS EUTOS) aimed to estimate incidence of CML in EUROPE. Results: For the analysis we made 2 data sets. First one includes data of 508 patients with 2005-2008 years of diagnosis from study EUTOS-OSP collected retrospectively from 36 regions of Russian. Median age at diagnosis was 49,3 years, range from 18 to 82, 47,6% of men, 6.7% in AC,BC phase, 29,3% at high risk by Sokal. Second set includes data of all 200 patients of PBS EUTOS study prospectively collected form 6 regions of Russia in 2008-2012 years. Median age at diagnosis was 50,4 years, range from 16 to 82, 50,8% of men, 6.0% in AC,BC phase, 31,7% at high risk by Sokal. Progression free survival (PFS) and complete cytogenetic responds (CCyR) probability were calculated by traditional KM method in OSP and PBS data sets. Also ICE estimations of the CCyR was done in this data sets. The 3-year PFS was estimated as 89.6% in OSP set and 88.8% in PBS set (fig. 1). KM estimations gives median time to CCyR =17.5 months in OSP and 12 months in PBS group, delta=5.5 moths (fig.2), if ICE estimations is used median time to CCyR =12 month in OSP, 8.5 month in PBS group, delta=3.5 moths (fig.3). The difference of CCyR between OSP and PBS was much less on fig.3 than on fig.2. The completeness of cytogenetic data in both studies was quite distinguishing. Percentages of patients with reported cytogenetic tests were following: in 6±3 month – 333/497 (67%) in OSP and 151/174 (87%) in PBS, in 24±3 month – 254/470 (54%) in OSP and 52/79 (66%) in PBS. Figure 1. KM estimations PFS in OSP (dash line) and PBS (solid line) sets Figure 1. KM estimations PFS in OSP (dash line) and PBS (solid line) sets Figure 2. KM estimations of CCyR in OSP (dash line) and PBS (solid line) sets. Figure 2. KM estimations of CCyR in OSP (dash line) and PBS (solid line) sets. Figure 3. ICE estimations of CCyR in OSP (dash line) and PBS (solid line) sets. Figure 3. ICE estimations of CCyR in OSP (dash line) and PBS (solid line) sets. Long term results of studies are almost identical (p=0.3, fig.1) although the KM estimations of response rates are essentially different (p Conclusions: Irregularity of time assessment of surrogate endpoints and missing data may lead to bias of classical estimations and then to wrong interpretations. The challenge of ICE usage instead of KM is illustrated on real data from CML registries. ICE estimations showed to be reliable and robust in comparison to classic right censored estimations. 1. References: So Y., Johnston G. Kim S.H.: // Analyzing Interval-Censored Survival Data with SAS® Software. SAS Global Forum 2010. Disclosures No relevant conflicts of interest to declare.

Introduction: Detection of bone marrow involvement (BM) is a factor of poor prognosis for diffuse large B-cell lymphoma (DLBCL), since DLBCL BM is characterized by aggressive course and low response level to standard chemotherapy (CT), and 5-year overall survival (OS) rate for this group is less than 30% after ÑHOP-like CT. Intensification of therapy in this group of patients can improve the results, except patients with bone marrow involvement at diagnosis. Bone marrow involvement is a poor prognostic factor for patients treated with high-dose chemotherapy. Bone marrow involvement in DLBCL by histology is detected in 10-30% patients. The importance of B-cell clonality examination in bone marrow as prognostic and staging factor has not been described in the literature. Aim: To evaluate the significance of the immunoglobulin heavy chain gene rearrangement analysis performed by PCR for identification of the bone marrow involvement frequency and its value for staging and prognosis in patients with de novo DLBCL treated with high-dose chemotherapy (HDC). Patients and methods: We performed a pilot prospective trial, including 175 consecutive adult patients (median age 45 years, range 18–67) with newly diagnosed DLBCL who were enrolled in HDC protocol (mNHL-BFM-90 program or scheme R-EPOCH/R-HMA) since June 2007 till July 2014. Their clinical characteristics included such factors as IPI and phenotype DLBCL by immunohistochemical study. Out of the 175 patients, 85 had a GCB phenotype and 90 - non-GCB; 36 patients (20%) had low IPI risk, 40 patients (23%) had low-intermediate, 38 patients (22%) had high-intermediate, 61 patients (35%) had high risk. B-cell clonality was evaluated using PCR amplification by IGH (FR1, FR2, FR3) and IGK (Vκ-Jκ, Vκ/intron-Kde) gene rearrangements with multiplex BIOMED-2 primer sets and subsequent fragment analysis using ABI PRISM 3130 Genetic Analyzer (Applied Biosystems).In 105 of 175 patients the study by BIOMED-2 multiplex polymerase chain reaction protocol of B-cell clonality of bone marrow was fulfilled. Statistical analysis was done using JMP ver. 10.0 (SAS, Cary, NC). Results: Histological and immunohistochemical studies validated bone marrow involvement in 19 patients (10.8%), including: concordant in - 12 patients (63%), and discordant - in 7 patients (37%). In 14 of these patients the B-cell clonality detection was performed and confirmed immunoglobulin (IG) heavy chain gene rearrangement in all cases. In 26 out of 105 patients, bone marrow involvement (24.7%) was revealed: in 14 patients bone marrow involvement was identified by histological examination and in 12 patients only by clonality of bone marrow. 12 patients with only B-cell clonality in bone marrow were classified by IPI: 4 (33%) patients had high IPI, 6 (50%) patients - high-intermediate IPI and low-intermediate IPI - 2 (17%) patients. So, in 17% patients had to change the risk group according to bone marrow involvement. Thus, 31 patients with bone marrow involvement signs were identified. Univariate analysis of the entire cohort (n = 175) revealed that both IPI and phenotype were not of prognostic significance (p > 0.05). In multivariate analysis, detection of B-cell clonality in bone marrow was an independent predictor of OS and relapse-free survival (RFS) (p < 0.005). (Fig.1-2). OS, RFS in patients with histological detection bone marrow involvement and with only B-cell clonality in the bone marrow did not differ. Conclusion:Detection of B-cell clonality in the bone marrow seems to be an independent predictor of outcome in de novo DLBCL pts, treated with high-dose chemotherapy, while IPI and phenotype DLBCL cannot be considered as risk factors for this group of pts. It seems to be reasonable to include the detection of B-cell clonality in the bone marrow in primary diagnostics of the DLBCL for staging and predicting response in HDC. Figure 1 Figure 1. Figure 2 Figure 2. Disclosures No relevant conflicts of interest to declare.

Introduction Intensive “pediatric oriented” treatment with heavy cytostatic load, incorporation of allogeneic HSCT is now considered a backbone approach in adult ALL therapy. Highly myelosuppressive treatment is more toxic and less reproducible, so RALL has initiated non-intensive but non- interruptive protocol “ALL-2009”and started a prospective multicenter trial for adult Ph-negative ALL based on: 1) the replacement of prednisolone (Pdn) 60 mg/m2 with dexamethazone (Dexa) 10 mg/m2 if blast cells are >25% in bone marrow after 7 days of prephase; 2) de-intensified but non-interruptive treatment with doses modification according to the myelosuppression with total treatment duration of 127 weeks; 3) prolonged implication of L-asparaginase (total proposed dose 590.000 IU/m2); 4) autologous hematopoietic stem cell transplantation (HSCT) after non-myeloablative BEAM conditioning followed by prolonged maintenance – for T-cell ALL patients. Allo-BMT was an option for high risk patients with sibling donors. The study is registered on the ClinicalTrials.gov public site; NCT01193933. Methods and patients From Jan 2009, till June 2014, 30 centers enrolled 250 pts: median age 30 years (15-60 years), 115f/135 m; in 2,4% phenotype was unknown (n=6), B-lineage ALL - 63,2% (n=158), T-lineage ALL - 34% (n=85), biphenotypic - 0,4% (n=1). Cytogenetics was available in 62,4% of patients (n=156) and 41% of them (n=64) had normal karyotype (NK). 25,2% of patients (n=63) were in the standard risk (SR) group (WBC 30 for B-lineage, >100 for T-lineage; EGIL BI, T-I-II-IV; LDH > 2N; late CR; t(4;11)-positive), 39 patients were not qualified by risk group. The analysis was performed in June 2014. The median time of follow-up was 26,1 mo. Results Prednisolone was replaced with dexamethazone after prephase in 68,1% of patients (135 of 198). The portion of non-responders to PRD in SR and HR groups was 54% and 67%, respectively (p=0,06). CR rate in 228 available for analysis patients was 87% (n=198), induction death occurred in 10,5% (n=24), resistance was registered in 2,5% (n=6). The majority of CR patients (91%) achieved it after prephase (7,1%, n=16) and the 1st phase of induction (83,9%, n=164). Late responders constituted 9% (n=18). None of those factors (PRD sensitivity, initial risk group, immunophenotype, late response) influenced overall (OS) or disease-free survival (DFS). OS rate in older ALL patients (>30) was substantially less than in younger ones (52,7% vs 73,6%, p=0,0009). DFS was comparable - 61,2% vs 71,5%, p=0,1. 24 of 75 (32%) CR T-ALL patients underwent autologous BMT after BEAM conditioning at a median time of 6 mo from CR and proceeded to further maintenance. No relapses were registered in this group so far. Allogeneic BMT was performed only in 14 patients (Ò-ALL-7, B-ALL-7) on the protocol. Totally 47 patients (20,6%) relapsed (16 with T-lineage, 31 with B-lineage ALL). At 48 mo OS for the whole group constituted - 65,6%, DFS - 69,3%. OS and DFS differed in B-ALL patients with NK in comparison with abnormal karyotype: 80% vs 57%,(p=0,01) and 81% vs 61%, respectively (p=0,02), but not in T-ALL patients. Conclusions Our data demonstrate that the proposed treatment approach is rather effective and reproducible. OS and DFS did not depend on various common risk factors (initial risk group, WBC, LDH, immunophenotype, late response, PRD resistance). The only independent risk factor for OS was age (>30 y). In B-cell ALL abnormal karyotype became an independent adverse risk factor for OS, DFS, relapse incidence. Fig.1 Overall survival (A) according to age in the whole cohort and disease-free survival (B) in B-cell ALL according to karyotype Table 1 (A) OS in different age groups (B) DFS in B-cell ALL Figure Figure. (A) OS in different age groups Figure Figure. (B) DFS in B-cell ALL Disclosures No relevant conflicts of interest to declare.

Introduction. The vast majority of AML clinical trials incorporate high-dose ARA-C (HDARA-C) as a basic approach. Though it was recently proved by a controlled prospective comparison that different treatment strategies in patients with AML did not show clinically relevant outcome differences (Th.Buchner, JCO, 2012), the RALSG initiated a randomized multicenter AML-10 trial (ClinicalTrials.gov Identifier: NCT01587430) aiming to evaluate the necessity of HDARA-C in consolidation in the context of high total dose of different anthracyclines/anthracenedione (660-720 mg/m2). Materials and methods. The patients aged 16-60 yy with de novo AML (except APL) were randomized before treatment start to different types of consolidation after two induction 7+3 with daunorubicin 60 mg/m2x3 and ARA-C 100 mg/m2 bid iv (1-7d) in the 1st course and 200 mg/m2/d (1-7d) continuous infusion in the 2nd course: (1st arm) two courses of 7+3 with Idarubicin (Ida) 12 mg/m2x3 and with Mitoxantrone (Mito) 10 mg/m2x3, in both ARA-C 100 mg/m2 bid iv (1-7d); (2nd arm) two courses of HDARA-C 1g/m2 bid iv 1-3 days with Ida 8 mg/m2 3-5 days and Mito10 mg/m2 3-5 days. After consolidation all pts proceeded to the maintenance 5+5 courses (ARA-C 100 mg/m2 bid iv 1-5 days with 6-mercaptopurine 50 mg/m2 1-5 days). Allogeneic HSCT was indicated to patients from intermediate and poor cytogenetic risk groups, late CR, WBC > 100*109/l. Results. From Jan 2010 till Jan 2014, 250 AML patients from 20 centers were randomized: (1st arm) 125 pts (m.age 45 y, 17-59 yy; 73f / 52m; LDH=674 IU (128-6653); cytogenetics favorable - 17,3%, intermediate - 66,7%, poor - 16%) and (2nd arm) 125 pts (m.age 43y, 16-60yy; 69f/56m; LDH=704 IU (123-8159); cytogenetics favorable - 20%, intermediate - 58,6%, poor - 21,4%). No molecular testing in cytogenetically normal pts was done. The analysis was performed in May 2014. The follow-up data were available in 199 pts. CR was achieved in 72,9% (n=145), early death was registered in 12,7% (n=25) and refractory disease - in 12,4% (n=24). Death in CR did not differed in a randomized groups (1st) 13,9% and (2nd) 13,7%. 17% of CR pts (n=20) were withdrawn from the protocol due to refusals (3,5%), infectious complications (13,5%). No relevant cardiotoxicity was registered on both arms. 12% (8 pts on the 1st arm, 9 - on the 2nd) were transplanted in 1st CR from HLA-identical donors. 3-years OS and DFS by intent-to-treat analysis were identical on both arms: (1st arm) 43% and 62%, (2nd arm) - 38% and 51%, respectively. For those patients in whom consolidation was fulfilled the comparison of DFS in different cytogenetic groups demonstrated equal efficacy of each consolidation arm: favorable - 85% (1st) and 85% (2nd), intermediate -65% (1st) and 57% (2nd), poor - 20% (1st) and 22% (2nd). In a multivariate analysis only cytogenetic group (HR=3,01, p=0,005) and CR achievement after the 2nd induction course (HR=2,83, p=0,0007) adversely influenced DFS. As the land-mark (5 mo of CR) analysis have shown, the bad prognosis of late CR could be modified by allo-HSCT in 1st CR: DFS of transplanted patients = 86%, non-transplanted=27% (p=0,03). Conclusion. Our interim analysis has demonstrated that conventional 7+3 consolidation is equal in long-term outcome to high dose ARA-C in case of the high total doses of different anthracyclines/ anthracenedione in induction/consolidation. CR after the 2nd induction became independent adverse prognostic factor (even inside cytogenetic risk groups) defining patients who should be transplanted in 1st CR. Figure 1 Figure 1. Figure 2 Figure 2. Disclosures No relevant conflicts of interest to declare.

Abstract 4431 The European Treatment Outcome Study (EUTOS) is register based international investigation started in June 2007. [1] The aim is to study the epidemiology of CML and to gain insight into the ‘real world’ treatment of patients with CML. Population base section (EUTOS-PBS) is the prospective study directed mostly to epidemiology aims. Russian part of the EUTOS-PBS registry collect data of newly diagnosed patients lived in 7 large regions of about 10 millions of population totally. EUTOS-PBS inclusion criteria are following: newly diagnosed CML (Ph +/BCR-ABL) started form 1st October 2009, age: older than 18. Russian CML group includes additional protocol for collection data for patients with clinical symptoms of CML. These patients are included into the roster table and after laboratory confirmation are enrolled into the main phase of the study. Thus, 174 patients were included in pre-phase, 142 (82%) had the diagnosis of CML which was confirmed by cytogenetic/molecular-genetic tests (Ph +/BCR-ABL +), 32 (18%) was not confirmed as CML. Among them 87% (n = 20) - have other Ph–negative chronic myeloproliferative diseases, and also acute leukemia (n = 1), cancer (n = 1), chronic inflammatory processes (n = 1). 142 patients with CML are 73 men, 69 women have the age from 18 to 82 (Me 49) years. 136 (96%) of patients are in the chronic phase, 6 (4%) -in the phase of acceleration, nobody in a blast ñrisis. The standard frequency analysis with adjustment to the standard population of WHO was carried out to estimate distribution. The results was presented in the table 1. As shown registered morbidity in 6 regions is not varied so much: source incidence is 0,58 (0,44–0,69); standardized on WHO incidence is: 0,7 (0,57 – 0,85); per 100 thousands per year. Estimated registered morbidity of CML in Russian regions are in 1.5–2 times less, than published morbidity in western countries. The analysis of the incidence in age stratums (table 2) shows that there is no much growth of age morbidity as expected. It obviously points to low detectability of new CML incidents in senior age categories (are more senior 60 years). This fact is probably the main reason of low total registered morbidity. Tabl.1. Incidence rate of new CML cases in 6 regions of Russia Region population (mln.) N CML for 100000. in year Standard of WHO Mordovia Republic 0.87 14 0.69 0.85 Kirov region 1.46 18 0.53 0.6 Perm territory 2.77 45 0.68 0.8 Bryansk region 1.35 17 0.53 0.65 Irkutsk region 2.55 36 0.56 0.68 Zabaikal's territory 1.36 12 0.44 0.57 Total 10.13 142 0.58 0.7 Table 2.CML incidence in age groups Age groups Male Female Maleandfemale 18–29 0.65 0.57 0.61 30–39 0.86 0.39 0.62 40–49 0.50 0.57 0.54 Conclusion: The CML incidence in Russia regions is underestimated. The main reason is an insufficient CML diagnostic screening in the senior age groups of population. References. 1. http://www.eutos.org/content/registry/documents/documents/e940/infoboxContent941/CML-Registry_February09.pdf Disclosures: Vinogradova: BMS: Consultancy, Speakers Bureau; Novartis: Consultancy, Research Funding, Speakers Bureau. Chelysheva:Novartis Pharma: Research Funding, Speakers Bureau; Bristol Myers Squibb: Research Funding, Speakers Bureau; MSD: Speakers Bureau. Senderova:Novartis: Consultancy. Turkina:Novartis Pharma: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau.

Abstract 2572 Adult ALL regardless recent advantages in adolescents and young adults is still considered to be a therapeutical problem. So called “a pediatric-like approach” applied in adult ALL is reported to be more reasonable even in the older adults (up to 55 y). RALL has initiated a prospective multicenter trial for adult Ph-neg ALL based on: 1) evaluation of b/m blast clearance after 7 days of Prednisolone (PRD) prephase and its substitution by Dexamethasone (DEXA) if b/m blast count was >25%; 2) continuous 2,5 years treatment schedule with prolonged L-asparaginase (Σ=590.000 IU); 3) evaluation of the impact of the late intensification (2 courses of HD of methotrexate and ARA-C) on MRD clearance. The study is registered on the ClinicalTrials.gov public site; NCT01193933. From Nov, 2008, till June, 2012, 24 centers enrolled 173 pts: median age 28 y (15–55), 71f/101m, 112 (64,7%) = B-lin, 54 (31,2%) = T-lin, 1 pt -undifferentiated AL (0,6%), 6 - uknown phenotype (3,5%), median LDH=848 ME (72–13061), median L=13,5 (0,6–556*109/l). Cytogenetics was evaluable in 58,3% of pts (n=101) and 46,5% of them (n=47) had normal karyotype (NK). Initial risk group was evaluated in 154 pts among whom 46 patients (29,9%) were in the standard risk (SR) group (WBC 30 for B-Lin, >100 for T-Lin, EGIL BI, T-I-II-IV; LDH > 2N, No late CR, t(4;11)-positive). 19/173 pts (11%) were not qualified. The analysis was performed in June, 2012. +8 day b/m blast count was reported in 149 pts and b/m blasts less than 25% were detected in 36,2% of pts. The portion of PRD non-responders was statistically different in SR and HR groups: 24/45 (53,3%) and 68/101 (67,3%) (p=0,01), confirming the initial risk groups identification. Induction results were obtained in 150 pts, and CR rate was identical in both risk groups (SR=86,9%; HR=84,1%) with total 12 induction deaths (8,0%) and 6 resistant leukemias (4,0%). With a median follow-up of 12 mo (1–36 mo) death in CR was reported in 9/132 (6,8%) pts. OS at 36 mo was 58,6%, DFS-68,3%. MRD analysis for clonal IgH and TCR rearrangements was carried out in 25 pts. And as in our previous studies (ASH 2006, abstr 2294) the clearance was slow with only 41,6% pts negative for MRD at day +133 (4mo) of the protocol. Two late intensification courses (day +157 = 5 mo) increased MRD negativity only up to 50%. Such slow MRD clearance did not correspond to higher relapse rate so far. Age, WBC, immunophenotype, LDH, risk group, +8 day b/m blast count, time to CR, time without treatment (<>8days), L-asparaginase cessation did not influence survival. OS and DFS differed in pts with NK vs all other abnormalities: 87,4% vs 57,9% (p=0,002) and 88,9% vs 66,5%, respectively (p=0,02). So, our data demonstrated that ALL-2009 protocol provided 58% 3-years overall survival and 68,3% DFS. In adult Ph-neg ALL normal karyotype predicts better survival. The MRD clearance is very slow while on this protocol. Disclosures: No relevant conflicts of interest to declare.

Abstract 4447 Background: 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. Objectives: To evaluate the results of CML treatment by TKI in clinical practice in the Russian Federation. Patients and treatment: 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. Result: 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 2nd 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). Conclusion: 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. Disclosures: 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.

Abstract 2090 BACKGROUND. Coinfection with hepatitis B virus (HBV) and hepatitis C virus (HCV) in immunocompromised patients (pts) with hematological malignancies is not well-studied problem. Early recognition of HBV and HCV infectioning incidence in such pts is difficult due to influence of cytostatic and immunosuppressive therapy and possible mutual HBV or HCV inhibitions. Independence of HBV and HCV infection events has to be discussed. AIM. To determine the prevalence of HBV and HCV co-infection in pts with hematological malignancies to check the possible correlation between the incidence of the infections. PATIENTS AND METHODS. All 265 patients treated in hematology department during 2004–2006 years were prospectively continuously monitored and examined for markers HBV and HCV (HBsAg, anti-HCV, DNA HBV, RNA HCV, HBeAg, anti-HBs, anti-HBc, anti-HBe) in serum, plazma, blood cells, bone marrow, cerebrospinal fluid) and clinico-biochemical symptoms of liver dysfunction were registered approximately every 3 weeks until 2008 year. Liver biopsy was performed on 64 pts in 2004–2006 yy, 23 pts esch with HBV and HCV immunohistology. Approximately 80% of pts were with acute leukemias (AL) and aplastic anemias (AA). Male; 47% (n=125), female; 53% (n=140). The median age was 38 years (range, 15 to 79). RESULTS. At the beginning of treatment and monitoring 17 of 265 pts (6.4%) had positive markers of HCV and the number of pts with positive markers of HCV increased up to 70 (26%) to the end of monitoring, and for HBV markers increased from 23 pts (8.7%) to 174 pts (65.3%). We found, that many pts were co-infected with HBV and HCV, and their total number increased from 5 pts (1,9%) äî 37 pts (14%). Positive tests of HBV and HCV co-infection was found in 57 pts of 265, that is 32.8% of 174 HBV-positive pts and 81.4% of 70 HCV-positive pts, odds ratio (OR=2.9) (95%CI =1.5–5.7), xi square significance p=0.0012. More complicate longitude analysis did not show that the incidence rate of second infection is significantly higher than the first. That means that the correlation between first and second infections is still questionable. Coinfection with HBV and HCV resulted in clinical presentation of hepatitis B and/or hepatitis C in most cases and cumulative incidence rate rises up to 100% at 630 day after the first appearance of any positive marker. CONCLUSION. The high prevalence of HBV and HCV coinfection of pts with hematological malignancies is attributed to common risk factors for infection transmission after transfusions of blood components and parenteral medical procedures. For pts with hematological malignancies after first detection of positive test for single marker of HBV and/or HCV it is very reasonable to intensify the monitoring of HBV and HCV markers and to follow clinical signs. Disclosures: No relevant conflicts of interest to declare.

Abstract 4996 It was shown that drug resistance, poor-risk cytogenetics and poor prognosis in AL is associated with high level of Bcl-2 expression and low Bax/Bcl-2 ratio ( We have studied the dynamics of Bcl-2, Bax, CD95 and ACE expression on CD34+ cells in peripheral blood (PB) and bone marrow (BM) in AL pts during treatment. PB and BM samples were collected before and on +36 day after chemotherapy. The antigens were detected by flow cytometry using monoclonal antibodies. We calculated 10 000 cells in each sample. 19 pts were included in the study: 10 - AML and 9 - ALL. The control group comprised 8 healthy donors. At time of diagnosis there were 40±5,7% of CD34+ cells in BM and 26±4,9% - in PB. There was no significant difference between AML and ALL. CD34+ cells in BM and PB of healthy donors constituted 1,6% and 0,27%, respectively. After induction therapy (+36 day) CD34+ cells decreased in BM to 6,1%±3,3 (p=0,0001), in PB to 3,7%± 2,7 (p=0,0008) in all pts. The data on antigens expression on CD34+ cells of BM and PB are presented in table 1 CD34+/Bcl-2+ CD34+/Bax+ CD34+/CD95+ CD34+/ACE+ BM PB BM PB BM PB BM PB AML pts n=10 0 day 38±11,6* 41±14 24,4±7,9 29,2±7,6* 16,4±8,5 23,2±7,8 21,7±9,5 20,8±8,7* 36 day 13,5±3,4** 23,7±5** 46,2±11,5 50,3±11 19,9±5,5 36,4±10 34±6,6 35±9,2** ALL pts n=9 0 day 36±11 33,7±12 46,2±9,4 37,4±3,7* 3,4±1,1* 7,1±2,5* 41±10,9 33,2±9,7* 36 day 18,4±5,8 26±8,9 38±11,8 40,5±10 26,2±9,1** 40,9±9,2** 34±10 62,8±10** Donors n=8 11,7±1,6 26,1±5,9 22,8±4 67,8±6,7 13,4±3,2 47,7±11,6 28±5,3 68,2±10,2 * − p CD34/Bcl-2 expression in BM in AML pts is significantly higher (p=0,04) at the diagnosis comparing with donors. CD34/Bcl-2 expression in PB in AML pts and in BM and PB in ALL pts is higher too, but not significantly. This expression level decreased substantially in BM and PB in AML pts on +36 day comparing with day 0 (p BM and PB CD34+ cells in donors had different expression characteristics of Bcl-2 and Bax, demonstrating much higher level of pro- and antiapoptotic markers in PB cells. On the contrast CD34+ leukemia cells in BM and PB had similar characteristics regarding CD34/Bcl-2 and CD34/Bax expression. This fact demonstrates the heterogeneity of donor CD34+cells in BM and PB and points that leukemia CD34+cells in BM and PB are rather similar. CD95 expression on CD34+ BM and PB before treatment is significantly lower (p=0,01, p=0,008) in ALL pts in comparison with donors, and this expression level increased after chemotherapy (p CD34/ACE coexpression in BM cells of leukemia pts and donors did not differ much at any time of evaluation. But CD34/ACE expression in PB cells of AML and ALL pts was much lower (p So, our data demonstrate that Bcl-2, Bax, CD95 and ACE expression on CD34+ cells in AL pts and donors significantly differs. The chemotherapy provokes critical changes in CD34/CD95 expression in BM and PB in ALL pts, CD34/Bcl-2 expression in AML pts and ÑÂ34/ACE expression in PB in all AL pts. Disclosures: No relevant conflicts of interest to declare.

Abstract 4840 The causes of drug resistance in acute leukemias (AL) have been studied very intensively and the key research was done on Bcl-2 family proteins. Last studies have showed that high level Bcl-2 expression in acute leukemia is really associated with drug resistance andpoor prognosis [Haematologica 2007, U. Testa]. It was demonstrated that lower Bax/Bcl-2 ratio ( We have studied the dynamics of Bcl-2 and Bax expression by flow cytometry in CD34+ cells of peripheral blood (PB) and bone marrow (BM) in pts with AL. PB and BM samples were collected before treatment, on days +8, +36, only PB - on day + 21. Bcl-2 and Bax were detected on CD34+ cells by flow cytometry using specific monoclonal antibodies: CD34 (8G12, BD), Bcl-2 (100, BD), Bax (2D2, Santa Cruz). ACE (9B9, BD) expression was also evaluated. We calculated 10 000 cells in each sample. 10 pts were included in the study: 4 AML, 6 ALL. The control group comprised 4 healthy donors. At time of diagnosis CD34+ cells number in BM was 38,7%± 9,75, in PB - 38,3%± 8,14 in AL pts, not differing much in AML and ALL, and indicating blast cells population. CD34+ cells numbers in BM and PB of healthy donors were 1,35% and 0,23%, respectively. After induction therapy and WBC recovery (days +36-38) CD34+ cells number in AL pts decreased dramatically in BM to 3,83%±1,51 (p=0,001) and in PB to 0,98%± 0,29 (p=0,0001), indicating the efficacy of chemotherapy. The dynamics of Bcl-2, Bax and ACE expression on CD34+ cells of BM and PB in AL pts are presented in fig.1-6 As seen in the fig.1,2 CD34/Bcl-2 expression in BM is significantly higher (p=0,04) and in PB is similar in AL pts at the diagnosis comparing with donors. It's also worth to note that BM and PB CD34+ cells in donors had different expression characteristics of Bcl-2 demonstrating much higher level of antiapoptotic marker in PB cells. On the contrast CD34+ AL cells in BM and PB had similar characteristics regarding CD34/Bcl-2 expression. This expression level decreased substantially in BM at day +36 comparing with day 0 (p=0,04), but it never reached the donors level remaining extremely high and supposing the persistence of antiapoptotic activity in CD34+ cells in AL pts. It did not change at all during chemotherapy in PB cells, being identical to donors characteristics. The fig.2,3 demonstrate that, CD34/Bax expression in BM is almost 3-times higher (p=0,14) and in PB is twice lower (p=0,02) in AL pts in comparison with donors. It's interesting that CD34/Bax expression in leukemic BM and PB cells looks very similar, when in donors we had very low expression in BM and high - in PB. This fact demonstrates the heterogeneity of donor CD34+cells in BM and PB and points that leukemia CD34+cells in BM and PB are rather similar in Bax expression. Chemotherapy caused the significant augmentation of CD34/Bax expression in PB on day +8 (p=0,01) and near significant on day +21 (p= 0,09) showing the increased level of “dieing” cells in PB after cytostatic influence. The fig. 5,6 show that CD34/ACE coexpression in BM cells of AL pts and donors did not differ much at any time of evaluation. But CD34/ACE expression in PB cells of AL pts was much lower (p=0,02) than in donors and substantially increased at day +36 almost reaching the donor level. We may conclude that Bcl-2, Bax, ACE expression on CD34+ cells in AL pts and donors significantly differs, the dynamics of expression in AL while chemotherapy shows critical changes in CD34/Bcl-2 expression in BM, CD34/Bax and CD34/ACE in PB. Disclosures: No relevant conflicts of interest to declare.

Abstract 4333 Adult acute lymphoblastic leukemia (ALL) differs from pediatric ALL by higher frequency of unfavorable biological features including cytogenetics (often t(9;22), rare t(12;21)), slower molecular response (MRD negativity is lower at day near +30 in adults - 47% vs 80%; Bruggemmann, Blood, 2006; Borowitz, Blood, 2010), more toxicity followed by less complience, all this translating in less efficacy. Another very important, early and simple predictor of antileukamia effect in ALL is prednisolone (PRD) sensitivity, that is to say tumor clearance within one week of prephase. It's a well documented fact in childhood ALL, but scarcely characterized in adults. 35% of adults with ALL are considered to be resistant to PRDN compaired to 10% children after evaluation of PB blast count on day +8 (Annino, Blood, 2002; Shrappe, Leukemia 2002), but few data exists about bone marrow blasts clearance. We initiated a prospective multicenter trial for Ph-negative ALL under the age of 55 based on: 1.evaluation of blast clearance in b/m after 7 days of PRD and its substitution by dexamethazone (DEXA) if blast count was 25% and more. 2. “no interruptions” protocol with 8 weeks induction and 5 consolidation phases followed by 2-years maintenance. 3. prolonged L-asparaginase application at 10.000 IU weekly in induction, once in two weeks in consolidations, twice a month in maintenance (total proposed dose 560.000 IU). The study started in April, 2009. 20 participating centers enrolled 77 patients (median age 27y (16-55), 44f, 33m, 61,5%=B-lin, 38,6%=T-lin; 41% with normal karyotype (NK)). 30,7% of patients were in the standrad risk (SR) group (WBC 30 for B-Lin, >100 for T-Lin, EGIL BI, T-I-II-IV; LDH > 2N, No late CR, t(4;11)+). The analysis was performed in June, 2010, and comprised 70 pts. The data on the day +8 b/m count was reported in 67 pts: 70% of them had b/m blasts 25% and more, thus were considered as non-responders to PRD (60 mg/m2) and were switched to DEXA (10 mg/m2). It's worth to note that the proportion of non-responders to PRD was almost equal in the SR and HR groups: 12 of 20 (60%) in SR and 35 of 47 (74,5%). CR rate was high in both risk groups (SR=95,5%; HR=89,4%) and immunological subsets (B=91,4%;T=91,6%). For the whole group of analysed patients (n=70) there were 5 induction deaths (7,1%) and 1 resistant leukemia (1,4%). Median of days without treatment during induction period was 8 days (0-56). Death in remission was reported in 2 of 64 CR pts (3,1%). Relapses occurred in 4/64 (4,2%). Within the short period of follow-up (14 mo) the probability of OS for 70 patients constituted 78,8%, DFS – 76,7%, continuous CR – 81,2%. The difference in DFS between PRD responders and non-responders was at borderline: 63,3% vs 93,8% (p=0,1), and statistically proved in pts with NK vs all other abnormalities: 100% vs 72% (p=0,03). Age, WBC, immunophenotype, risk group, time without treatment did not influence survival. We concluded that in adult Ph-negative ALL the proportion of non-responders to PRD is very high (70%), thus providing much poorer results than in children; sensitivity to PRD may still be used as very simple discriminative marker of unfavorable prognosis. Disclosures: No relevant conflicts of interest to declare.

Russian Leukemia study group is presenting the final analysis of the APL-06.01. randomized clinical trial. The aim of the study was to identify the efficacy of ATRA substitution of each other chemotherapy course while the 2-yrs maintenance after three induction/ consolidation 7+3 with daunorubicin dose of 180 mg/m2 per course and ATRA for 30 days while the first induction. The patients were randomized for two types of maintenance - (I type) rotation of 5-days ARA-C (100 mg/m2 bid) combined with daunorubicin (45 mg/m2 for 2 days, till the total dose of 650 mg/m2) or 6-MP (50mg/m2 p.o.5 days) or CHP (800 mg/m2 i.v.1 day) or (II type) rotation of the same courses of chemotherapy with 5-days 45 mg/m2 ATRA course. The II type of maintenance treatment contained twice less chemotherapy. The intervals between courses were 4 weeks From July, 2001 till January, 2006 114 APL patients from 26 centers were enrolled in the study. In 95% of pts APL was confirmed by cytogenetics or PCR. 102 patients were included in the analysis. CR rate was 85%, ED rate -15%, 4-yrs OS -68,3%, DFS - 77,4%, CCR - 89,5%. Suvival analysis according to randomization did not demonstrate statistical differences, but showed a trend (p=0,06) towards better DFS and CCR in patients maintened with chemotherapy only: 85,2% and 94,3% (I type) and 77,7% and 85,6% (II type). In the multivariant analysis only one factor was defined as statistically significant - the number of the patients randomized by the participating centers. OS and DFS were much higher in the centers randomized 6 and more patients comparing with less than 6 patients: 82,9%and 90,7% vs 48,8% and 63%, respectively (0,003). 1. So we can suggest that maintenance with ATRA alternating with chemotherapy is less effective than chemotherapy only. Whether addition not substitution of ATRA to chemotherapy maintenance will change the results will be checked in the next study.2. The experince of the centers in APL treatment is a cruicial point for survival.