ALBERT

Description: Our previous PALG study in 445 de novo AML patients has demonstrated that addition of cladribine to the standard daunorubicine-cytarabine (DA) remission induction regimen - DAC has a beneficial influence on both the CR rate after one induction cycle (p=0,0008) and on survival in patients older than 40 y (Leukemia2004,18:989–97, updated at 7 y: ASH 2006, Abstr.N#2003). The goal of this study was to evaluate the efficacy of original combination including another purine analogue fludarabine – DAF (daunorubicine 60 mg/m2/d iv, d 1–3; cytarabine (AraC) 200 mg/m2/d ci, d 1–7, and fludarabine 25 mg/m2 iv d 1–5) in untreated patients with AML, aged up to 60 y, based on head to head comparison with DAC - (DNR, AraC, Cladribine), and standard DA regimens. We evaluated earlier the DAF protocol in relapsed or refractory AML (PALG pilot study; Ann Hematol.2008, 87:361–7. Epub 2007 Dec 12); the tolerance was good, CR 44%, LFS 38%. Primary objectives of the presented trial were: complete remission rate (CR) and overall survival (OS); secondary objectives were: toxicity and leukemia-free survival (LFS). Additional analysis was planned for patients submitted to an early bone marrow allotransplantation (alloBMT) after CR. Patients achieving CR received two courses of subsequent intensive consolidation: HAM (HD AraC, mitoxantrone) HD AraC. Reduction of consolidation was accepted in patients treated with early alloBMT. In case of partial remission (PR) after the first induction course the same regimen was repeated. Patients with no remission (NR) or with PR after 2 induction courses were withdrawn from the study. Between 09.2004 and 05.2008, 673 adult untreated AML patients aged 18–60 y, median 47 y, sex: male 49,5%, female 50,5%, treated in 18 co-operating Polish Adult leukemia Group (PALG) centres were centrally randomised to either DAF (n=225), DAC (n=224) or DA (n=224) arm (1:1:1). PML/RAR alfa positive - FAB M3 cases were excluded. The study groups were well balanced in respect of age, sex, FAB subtype, and WBC. After a single induction course the CR rate for patients receiving DAC equalling 63% was significantly higher if compared with DA - 51% (p=0,01), whereas no significant differences were noted between DAC vs. DAF - 55% and DAF vs. DA subgroups. Also the entire CR rate of 68% in the DAC arm was higher in comparison with DA one - 57% (p=0,02). No significant differences were found between DAC vs. DAF - 60%, and DAF vs. DA. At median time of 24 months (longest observation time 3,5y) the OS rate equalled 51% for the DAC treated subgroup and was higher in comparison to the standard DA arm - 39% and the DAF arm - 36% (p=0,03). The leukemia free survival rates (LFS) in DAC, DA and DAF treated cohorts equalled 51%, 32% and 41% respectively (p=NS). The early death rates of 8–10%. were similar in the studied treatment subgroups. All patients developed WHO grade IV thrombocytopenia and agranulocytosis. The frequency and severity of infections, mucositis, vomiting, diarrhoea, alopecia, polyneuropathy as well as of cardiac, liver or kidney dysfunctions were comparable in particular arms. In conclusion, this randomised study proves that the addition of cladribine to the standard DA induction regimen (DAC) improves CR rate and the overall survival in adults with AML aged up to 60 y, without additional toxicity. This beneficial effect was not observed in patients treated using the DAF protocol with fludarabine added to the standard “DA 3+7” schedule

Description: Background. Early occurrence of the multidrug resistance (MDR) in de novo acute myeloid leukaemia (AML) may contribute to the treatment failure.The aim of this study was to investigate prospectively the clinical significance of the MDR proteins overexpression and their functional augmenting, in the context of other AML prognostic factors, such as age, immunophenotype and cytogenetic profile. We examined expression of MDR proteins: MDR1, MRP1, MDR3, BCRP, LRP and GSTπ and performed drug resistance functional assay in peripheral blood blasts of 25 patients with de novo AML at diagnosis and after the first chemotherapy cycle consisting of a 3 + 7 combination of DNR/Ara-C. MDR proteins presence and their functional activity (measured by fluorescent Rh123 dye efflux) were estimated by flow cytometry. Results: Thirteen out of the 25 AML patients (52%) attained a CR with induction treatment, one had PR and eleven did not achieve remission. Out of 10 patients without CR, 2 died in aplasia and 9 were classified as an early death due to disease progression. All patients who achieved remission were younger than 55 years. Among 11 patients without remission, 9 expressed CD34; 6 of them had intermediate and 5 unfovorable cytogenetic profiles. In 10 out of 25 patients (40%) overexpression od MDR1 was shown at diagnosis, and was irreversible in 9 of them, those with poor clinical outcome (6 did not achieve CR, 1 had PR and one who obtained CR relapsed), whereas one patient who reversed achieved CR. The functional MDR assay showed the increased Rh123 efflux, both at diagnosis and after the first chemotherapy cycle in 12 patients (48%) and it influenced patients’ outcome in similar manner as MDR1 expression. At diagnosis other MDR proteins were also elevated in some AML patients:GSTπin 19 (76%), LRP in 9 (36%), MRP in 4 (16%) and MDR3 in 2 (8%). Seven AML patients (20%), both at diagnosis and after the first chemotherapy cycle co-expressed MDR1 with other multidrug resistance proteins and had enhanced Rh123 efflux. This co-expression resultes in 6 of them in chemotherapy resistance; the remaining one who achieved remission was young and had favorable cytogenetic profile. The results obtained demonstrate that the advanced age, unfavorable cytogenetic profile, overexpression of MDR1 at diagnosis and co-expression of other MDR proteins together with their functional activity contribute to the treatment failure in de novo AML.

Description: Objectives:Cytogenetics is one of the most important prognostic factors in acute myeloid leukemia (AML). Two major, partially overlapping cytogenetic subsets of AML associated with an adverse prognosis, are AML with complex karyotype (CK) and AML with monosomal karyotype (MK). MK has been shown to constitute a cytogenetic feature that identifies AML patients (pts) with very poor outcomes when treated with currently available therapy. CK-AML pts are very heterogeneous cytogenetically, and treatment outcomes of these subsets are also influenced by TP53 alterations, complexity of the karyotype or presence of residual normal metaphases. However, impact of all these variables on outcome of CK-AML patients was so far analyzed separately. The aim of our study was to assess treatment outcome of CK-AML patients with or without MK regarding some cytogenetic and clinical features. Materials and methods: One hundred twenty five newly diagnosed AML patients with CK treated between January 2007 and January 2013 with PALG protocols (Holowiecki et al., JCO 2012) were included into the study. Cytogenetic analysis was performed on metaphases from bone marrow aspirates taken at diagnosis using standard banding techniques. Karyotypes were reported in accordance with the ISCN 2009. CK was defined as a presence of ≥ 3 unrelated abnormalities. MK was defined by the presence of an autosomal monosomy in conjunction with at least one other autosomal monosomy or structural abnormality in the absence of t(8;21), inv(16), t(15;17) (Breems et al., JCO 2008). FISH method was used to verify MK in all cases with monosomy as well as to assess 17p13 (TP53) deletion. Results:Clinical characteristics. The median age of all pts was 60 years (range 19-85 years). FISH verification proved the MK karyotype (MK+) in 75 out of 125 (60%) pts with CK-AML. Remaining pts had non-monosomal CK (MK-). Sixty six (55%) pts received intensive induction chemotherapy (IC) according to PALG protocols and 59 pts received non-intensive treatment with low-dose cytarabine (LDAC) or best supportive care (BSC). Baseline characteristics were generally balanced between MK+ and MK- groups in terms of age, WBC and PLT counts, hemoglobin level, percentage of bone marrow blasts at diagnosis and presence of residual normal metaphases in the karyotype. Higher proportions of MK+ pts had deletion of 17p13 (TP53) (47,9% vs. 20,4% of MK-; p=0.0017) as well as ≥5 cytogenetic aberrations (93,3% vs. 74%; p=0.004). Furthermore, there were no differences in the proportion of IC, LDAC and BSC strategies between both groups. Treatment Response and Outcome. With the median time of follow-up 7,7 months (mos), median OS in MK- pts was significantly longer compared to MK+ group (4,5 mos vs. 2,0 mos; p=0.0075). 66/125 CK-AML pts received standard IC according to PALG AML protocols (DA-36 pts; DAC-27 pts and DAF-3 pts). Only 7 pts underwent allogeneic stem cell transplantation (allo-SCT). In intensively treated pts the overall CR rate in MK- was about twice as high as in MK+ group (62,1% vs 32,4%; p=0.013). The median OS in MK- pts was longer compared to MK+ group (6,8 mos vs. 2,7 mos; p=0.016). Probability of 1-year OS in MK+ vs. MK- group was 14% vs. 30%. In multivariate analysis we have found that WBC 〉20 G/l, MK and ≥5 chromosomal abnormalities were independent prognostic factors associated with significantly shorter OS (Table 1). In contrast, allo-SCT was associated with survival benefit. Furthermore, we analyzed the impact of purine analogue containing induction regimens on treatment outcome. We found that addition of cladribine to the standard DA regimen improves OS in MK- but not in MK+ group (Figure 1). Conclusions: Monosomal karyotype, high WBC count and high complexity of the karyotype (≥5 aberrations) are associated with more aggressive clinical course and short survival in high-risk CK-AML. Cladribine added to standard DA induction regimen prolongs survival of pts with complex but not monosomal karyotype. *AW and EW equally contributed to the study. Figure 1 Figure 1. Figure 2 Figure 2. Disclosures No relevant conflicts of interest to declare.

Description: Background Chronic myeloid leukemia (CML) biology seemed to be perfectly explored especially at the beginning of tyrosine kinase inhibitors era (TKI). Later years with imatinib and second generation TKI showed variety of resistance mechanisms and it became obvious bcr-abl chimeric gene is not the only enemy to fight. Some studies assumed the decreased rate of programmed cell death (apoptotic) to be the primary mechanism by which BCR-ABL effects expansion of the leukemic clone in CML. Other studies showed the important role of patients adherence in achieving best possible response for imatinib. Imatinib plasma level was recognized as a useful tool for adherence evaluation. In this study we evaluate the expression of apoptotic marker, Annexin V in CD34+CD117+ cells of CML patients in first chronic phase treated with imatinib and try to find the correlation between this expression and cytogenetic response or imatinib plasma level. Patients The group of 54 CML patients (F/M = 30/24, median age, 50.5) in first chronic phase treated with imatinib (400 mg daily) was analyzed. The median time of treatment was 17 months (min. 12 months, max. 24 months. Only patients with the conventional translocation (Philadelphia chromosome) without additional chromosomal aberrations or clonal evolution during the treatment period were included in the study. Patients were categorized according to ELN criteria for cytogenetic response: complete cytogenetic response (CCyR) vs. no cytogenetic response (NCyR, defined as everything less than CCyR), and for molecular response: major molecular response (MMR) vs. no molecular response (NMR). Results In the cohort of 54 patients, 39 achieved CCyR in a median time of 12 months. Among these patients, 30 achieved MMR within the same time. Bone marrow CD34 positive cells were assessed for expression of CD117 and Annexin V in all groups of patients (CCyR with MMR, CCyR with NMR, and NCyR). The mean percentage of CD34+CD117+ cells was significantly higher in the NCyR group (7.67±5.62) in comparison with the CCyR group (2.27±1,78; p=0.002). The difference between MMR and NMR subgroups was not significant. While analyzing the CD34+CD117+ population, we found a significantly higher percentage of apoptotic cells (Annexin V positive) in the CCyR group (4.65±4.55) than in the NCyR group (1.67±1.22; p=0.004). Once again this difference was not significant between MMR and NMR subgroups. Serum imatinib levels were quantified in both CCyR and NCyR groups. We found higher values in the CCyR group (1244 μg/l±599) than in the NCyR group (1192 μg/l±593) but this difference was insignificant. Conclusions It was recently reported that c-kit must be inhibited to allow apoptosis of CML cells. Our results also correspond with these data. Not only was a lower percentage of CD34+CD117+ cells found in the CCyR group, but the fraction of these cells that were apoptotic was significantly greater compared with the NCyR group. Although other studies have indicated that trough plasma concentration of imatinib reflects clinical response in chronic phase of CML, we did not observe this. Our results showed higher imatinib levels in CCyR, but these data were insignificant. In conclusion, our results indicate that to achieve optimal treatment response in CML patients, c-kit kinase inhibition may be a requirement for successful proapoptotic activity of imatinib. Disclosures: No relevant conflicts of interest to declare.

Description: Four women aged from 48 to 51 years with persistent polyclonal B-cell lymphocytosis (PPBCL) were studied for the clonality of B-cell population and HLA haplotype. All patients were smokers, one presented an immune deficiency syndrome due to decreased IgG and IgA levels, the others were asymptomatic. All patients presented serum increase of polyclonal IgM (5.55 – 8.12 g/L), absolute peripheral lymphocytosis ranging from 6100 to 10500/μL with elevated proportion of B cells, the percentage of CD5/CD19 lymphocytes 〈 5%, and binucleated/bilobulated lymphocytes accounting for 5–9% of nucleated cells on the blood smear. In one patient, cytogenetic study revealed trisomy 3 in 4 out of 40 metaphases, +18 in 2 cells, and i(18q), +15, t(13,14) in single cells. In the remaining patients no clonal chromosomal abnormalities were found. All patients were HLA typed by PCR based sequence specific primer amplification. HLA allele and haplotype incidence in patients’ group were compared to healthy population of 286 ethnically matched (Caucasian, Polish) controls. DRB1*07 allele was found in 2/4 patients, seems than to be elevated than in general Polish population but a small number of patients does not allow to perform relevant statistical tests. Moreover we found significantly more frequent B*08-DRB1*03 fragment of ancestral HLA 8.1 haplotype (8.1 AH) in PPBCL patients (3/4) than in control group (47/286) (OR=15.3; 95% CI 1.55–150; p=0.02). Peripheral blood mononuclear cells from all PPBCL patients were also studied for monoclonality in immunoglobulin (IGH VH-JH, incomplete DH-JH, IGK, IGL) and crosslineage TCR (TCRB, TCRG, TCRD) genes rearrangements according to BIOMED-2 protocol. The multiplex PCR reactions were followed with heteroduplex analysis of PCR products. We found polyclonality of lymphocytes population in all tests except incomplete DH7-JH IGH rearrangements in 2 patients. The described gene rearrangement was not related to other upstream DH or downstream JH gene segments. The HLA incidence we found is distinct from previously described elevated incidence HLA DRB1*07 allele and may suggest another genetic background of PPBCL pathogenesis. Moreover, our finding of high prevalence of 8.1 AH, known to be more frequent in autoimmune diseases, and to worsen the prognosis in some infectious diseases and non-Hodgkin lymphomas, as well as of the incomplete DJ monoclonality in 2/4 patients, warrant further studies aiming to determine the relationship between PPBCL, immune disorders and true lymphoproliferative diseases.

Description: BACKGROUND: Chronic myeloid leukemia (CML) has been a model disease for a variety of studies concerning scoring systems, graft versus leukemia effect or tyrosine kinase inhibitors (TKI) treatment for many years. Scoring systems playing an important role in modern medicine to establish risk-adjusted optimal therapy [1] have been always essential for CML changing treatment modalities [1-3]. The three principal risk scores : Sokal [2], Hasford [1] and European Treatment and Outcome Study (EUTOS) [3] were established in different eras of CML therapy with implications for prognosis and disease outcome [4]. Hasford metric was designed based on data of patients treated with interpheron alpha [1] and it failed to differentiate patients who achieved low and intermediate risk scores according to CCyR, MMR, and 5 years EFS [5]. However in our previous study we found Hasford score to be correlated with the long-term molecular response in patients treated with imatinib [6]. This study presents the analysis of patients treated with second generation tyrosine kinase inhibitors (2G-TKI) due to their loss of MMR on imatinib. Hasford score still distinguish patients with low and intermediate risk and correlates with 18 month molecular response. PATIENTS AND RESULTS: The original group of 88 CML patients (F/M:42/46, median age 51 (21-83), 57 low risk and 31 intermediate risk assessed by Hasford risk score) in first chronic phase without any additional chromosomal abnormalities receiving standard dose imatinib was described in our previous study [6]. Of these, 42 patients lost MMR in a median time of 47 months. Within this group we identified 20 low risk (LR) and 22 intermediate risk (IR) patients. All 42 patients were switched to 2G-TKI. The observation after 3 months of 2G-TKI treatment was also previously described. After 18 months of 2G-TKI treatment median bcr-abl transcript levels in the LR group were 0.002 (0.000-0.02) but in the IR group bcr-abl levels were 0.03 (0.000-21.1) (p=0.03, Figure 1). All 20 low risk patients achieved major molecular response (MMR). In the intermediate risk group the response rate (MMR) was approximately 73% (16/22) and there is a significant difference in a probability of achieving MMR in both groups (Fig.2, p=0.0002). CONCLUSIONS: We are aware of Hasford score limited usefulness in predicting MMR in large studies. However in our study it is still a tool to distinguish low and intermediate risk patients by their molecular response on 2G-TKI after imatinib failure. We find our results relevant to the discussion on optimizing scoring systems and first line treatment of CML patients. REFERENCES: 1. Hasford J, Pfirrmann M, Hehlmann R, Allan NC, Baccarani M, Kluin-Nelemans JC, et al. A new prognostic score for survival of patients with chronic myeloid leukemia treated with interferon alfa. Writing Committee for the Collaborative CML Prognostic Factors Project Group. Journal of the National Cancer Institute. 1998;90:850-8. 2. Sokal JE, Cox EB, Baccarani M, Tura S, Gomez GA, Robertson JE, et al. Prognostic discrimination in "good-risk" chronic granulocytic leukemia. Blood. 1984;63:789-99. 3. Hasford J, Baccarani M, Hoffmann V, Guilhot J, Saussele S, Rosti G, et al. Predicting complete cytogenetic response and subsequent progression-free survival in 2060 patients with CML on imatinib treatment: the EUTOS score. Blood. 2011;118:686-92. 4. Hu B, Savani BN. Impact of risk score calculations in choosing front-line tyrosine kinase inhibitors for patients with newly diagnosed chronic myeloid leukemia in the chronic phase. European journal of haematology. 2014;93:179-86. 5. Yahng SA, Jang EJ, Choi SY, Oh YJ, Bang JH, Park JE, Jeon HL, Lee SE, Kim SH, Byun JY, Kim DW. Comparison of Sokal, Hasford and EUTOS Scores in Terms of Long-Term Treatment Outcome According to the Risks in Each Prognostic Model: A Single Center Data Analyzed in 255 Early Chronic Phase Chronic Myeloid Leukemia Patients Treated with Frontline Imatinib Mesylate. Blood 2012;120:Abstract 2794 6. Dybko J, Medras E, Haus O, Jazwiec B, Wrobel T, Kuliczkowski K. The Hasford Score Correlates with the Long-Term Molecular Response to Imatinib Treatment for Chronic Myeloid Leukemia Patients and May be Useful for Differentiating Low and Intermediate Risk Patients: A Single Institution Experience. Blood 2014;124:Abstract 3152 Figure 1. Figure 1. Figure 2. Figure 2. Disclosures No relevant conflicts of interest to declare.

Description: Abstract 3537 Objectives: Cytogenetics is one of the most important prognostic factors in acute myeloid leukemia (AML). Breems et al., based on banding techniques (BT), have identified a monosomal karyotype (MK) to be associated with particularly poor survival. MK is defined by the presence of an autosomal monosomy in conjunction with at least one other autosomal monosomy or structural abnormality. However, classical BT may be not sufficient to confirm the “real” loss of a particular chromosome, especially in patients with complex karyotype (≥ 3 or ≥ 5 separate abnormalities) where parts of „missing” chromosomes could be involved in structural aberrations such as: additions, derivative chromosomes, rings, marker chromosomes and dicentrics. Molecular cytogenetic techniques, such as FISH, could be useful to verify if observed monosomy was “total” (loss of a complete chromosome) or “partial” (loss of only a part of chromosome including centromere). The aim of our study was to assess if the type of monosomy (total or partial), defined using FISH influences the prognosis of AML patients with MK. Materials and methods: Fifty newly diagnosed AML patients with MK, treated between January 2005 and January 2011 with PALG AML1/2004 and AML2/2004 protocols were included into the study. Cytogenetic analysis was performed on metaphases from bone marrow aspirates taken at diagnosis using standard BT. Karyotypes were centrally reviewed by two independent cytogeneticists and reported in accordance with the ISCN. In 41 cases FISH was performed with painting probes and in justified cases additionally with satellite probes and locus-specific probes to assess the type of monosomy. In 9 patients no confirmation by FISH was needed. Results: In 8/50 (16%) patients FISH verification proved the complex, but not monosomal (total or partial) karyotype. These patients were excluded from further study. The median age of 42 evaluable patients was 58 years (range 20–71 years). There were 26 males and 16 females. Twenty three (55%) patients received intensive induction chemotherapy according to PALG protocols (Holowiecki et al. Leukemia 2004), 8 patients - low dose cytarabine and 11 patients with high frailty index received treatment with hydroxyurea (n=9), and best supportive care (n=2). In 38/42 (90.5%) analyzed cases with MK abnormalities were complex. In all but one ≥5 separate aberrations were present. In 27/42 (64.3%) cases a total monosomy was confirmed by FISH (group A) and in 15/42 (35.7%) cases FISH revealed a monosomy to be the partial one (group B). Both groups A and B were comparable in terms of age, sex, immunophenotype and factors associated with tumor mass (leukemic bone marrow infiltration, WBC and peripheral blood blast count, as well as LDH activity). There was also no difference in the proportion of intensive and non-intensive treatment strategies between both groups. Six (26,1%) of intensively treated patients achieved complete remission (CR). The CR rate in patients with partial monosomy (40%) was higher than in total monosomy group (15,4%), however the difference was not significant (p=0.19; Fisher's exact test). The median overall survival (OS) for all evaluable patients was 66 days (range 1–659 days) and the probability of OS at 1 yr was 14% (95% CI 4–23%). Total monosomy was the only factor associated with decreased probability of OS both in univariate (p=0.036) (Fig. 1) and multivariate (p=0.037) analyses in AML patients with MK. Additionally, in patients with total monosomy the frequency of distinct monosomies was analyzed. The most frequent monosomies were monosomy 7 (n=13; 48%) and monosomy 18 (n=10; 37%). Other total monosomies included: monosomy 17 (n=3; 11%), monosomy 16 (n=2; 7%) and others (n=4). We did not observe any total monosomy 5. Conclusions: Our results indicate for the first time that partial monosomy is associated with significantly better OS than total monosomy in high risk AML with MK and provide further evidence for the heterogeneity of this defined cytogenetic group. These data also clearly demonstrate an important role of FISH method for precise evaluation of complex karyotype, which results in correct classification within MK group, as well as in adequate description of monosomy type. Disclosures: Wierzbowska: Genzyme: Membership on an entity's Board of Directors or advisory committees. Dmoszynska:Roche: Honoraria; Mundipharma:.

Description: The emergence of GATA2 deficiency as a germline predisposition to myeloid malignancies raises questions about the nature of acquired secondary genetic and epigenetic events facilitating leukemogenesis. Previously, mutations in ASXL1 were implicated as a possible somatic driver in single cases of GATA2-related MDS. However the landscape of secondary changes had not yet been systematically examined in larger MDS cohorts, and accounting for confounding factors. In this study, we used next-generation genomic platforms to investigate targeted mutational landscape and global epigenetic profiles in patients with GATA2 deficiency. In a large cohort of consecutively diagnosed children with MDS we had initially established that GATA2 deficiency accounts for 7% of primary MDS cases. Exploring the known association between GATA2 mutated (GATA2mut) cases and monosomy 7 (-7), the prevalence of GATA2 deficiency was very high in patients with -7 (37%), reaching its peak in adolescence (〉70%). We next tested 60 GATA2-deficient patients with MDS for the presence of secondary mutations using targeted NGS for genes involved in myeloid malignancies. Somatic status was confirmed by matched analysis of fibroblasts, hair follicles or T-cells. Single hematopoietic CFU colonies were sequenced to identify subclonal patterns. For comparison, a GATA2 wildtype (GATA2-WT) cohort of 422 children and adolescents with MDS enrolled in the studies of the European Working Group of Childhood MDS were analyzed by targeted NGS. Somatic mutations were detected in 45% (27/60) of GATA2mut as compared to 19% (82/422) GATA2-WT MDS cases (p

Description: Abstract 4337 This trial is a continuation of the earlier studies concerning optimalization of induction chemotherapy in acute myeloid (AML) patients using purine analogues (Ho≥owiecki J., Grosicki S., Robak T. et al. Leukemia 2004, Holowiecki J, Grosicki S, Giebel S. et al. J Clin Oncol. 2012). The goal of the study was to evaluate the toxicity and efficacy of combination including idarubicin – IAC (idarubicin 10 mg/m2/d iv, d 1–3; cytarabine 200 mg/m2/d ci, d 1–7, cladribine 5 mg/m2/d d 1–5) in comparison with DAC (daunorubicin 60 mg/m2/d iv d 1–3 in place of idarubicin). The primary endpoints were complete remission rate (CR) and toxicity, the secondary one was overall survival (OS). Patients who achieved CR received two courses of subsequent intensive consolidation: HAM (HD AraC, mitoxantrone) and HD AraC. Reduction of consolidation was accepted in patients treated with early alloBMT. In case of partial remission (PR) after the first induction course the same regimen was repeated. Patients with no remission (NR) or with PR after 2 induction courses were withdrawn from the study. Between 03.2009 and 03.2012, 52 adult untreated patients aged median 57 years (20–72), treated in one center - Department of Hematology of City Hospital in Chorzow/Poland were included to this study; 46% of study participants were male, 54% female and they were evaluated as fit with possibility of intensive chemotherapy including HSCT. PML/RAR alfa positive – FAB M3 cases were excluded. DAC regimen was a standard induction in this group of AML patients. When there was no possibility to apply DAC regimen because of not having access to daunorubicin in our center, the IAC regimen was used. Material and the results are summarized in the table. Outcome DAC (n = 30) IAC (n = 22) p Age (median) 20–72 (55) 38–70 (59) NS Sex (%) K-53, M-47 K-55, M-45 NS WBC at dgn. × 103/L median (range) 27,7 (2,3–257) 11,0 (0,9–210) NS Cytogenetic risk (%) Low 0 0 NS intermediate 50 64 NS High 7 5 NS No data 43 31 NS HSCT (n) auto/allo 2/7 1/5 NS CR rate (%) 70 59 NS 3-yr OS (%) 26 23 NS 2-yr LFS (%) 28 36 NS The study groups were well balanced with respect to age, sex, WBC and cytogenetics. The entire CR rates in both groups did not differ, and they were similar to previously published results after DAC induction regimen. All patients developed WHO grade IV thrombocytopenia and agranulocytosis. The frequency and severity of infections, mucositis, vomiting, diarrhea, alopecia, polyneuropathy as well as of cardiac, liver or kidney dysfunctions were comparable in particular arms. There were no significant differences in the OS and LFS rates. In conclusion, the results of our study authorize the replacement of daunorubicin to idarubicin in DAC induction regimen without risk of additional toxicity, and with similar outcome. Disclosures: No relevant conflicts of interest to declare.

Description: Abstract 2747 Poster Board II-723 Background: A distinct phenotype of combined ex vivo drug resistance and gene expression associated with this phenotype discriminates treatment outcome and identifies a subset of patients with a markedly inferior outcome in childhood acute lymphoblastic leukemia (ALL). No similar relationship was found so far in acute myeloblastic leukemia (AML). We hypothesized that drug sensitivity profile combined with gene expression profile can provide a new insight into selection of drugs used in high-dose therapy before hematopoietic stem cell transplantation and determine the role of specific drugs. Objective: The aim of the study was to analyze the gene expression profile in correlation to the ex vivo obtained chemosensitivity profile of drugs used in high-dose therapy before hematopoietic stem cell transplantation in children with ALL and AML. Methods: We tested leukemic cells from 56 children (43 ALL de novo, 8 relapsed ALL, 5 AML de novo) for ex vivo sensitivity to etoposide, fludarabine, 4-HOO-cyclophosphamide, busulfan, treosulfan and melphalan. The cells were then subjected to an assessment of global profile of gene expression to identify differentially expressed genes in drug-sensitive and drug-resistant ALL. Cells were isolated from bone marrow at the initial diagnosis of leukemia or its relapse. In vitro cytotoxicity was analyzed by means of the MTT assay. The drug resistance was expressed as the IC50, the inhibitory concentration to 50% of the cells. RNA was extracted with the use of Trizol, purified and assessed for integrity. Samples were hybridized to the Human Genome U133A Chip oligonucleotide microarrays (Affymetrix) according to manufacturer's protocol. Dataset was pre-processed by RMA method and small variability genes were filtered out. The final analysis was carried out in 13 835 probe sets. Non-parametric Spearman's correlations of IC50 and gene expression values were analyzed. Results: From all analyzed drugs, the largest number of genes significantly associated with the chemosensitivity profile across samples was observed for etoposide. We found 386 probests significantly correlated with the IC50 values (Spearman's correlation coefficient ranging from R==0.7 to R=0.61, p