ALBERT

Description: Activation of the Wnt/β-catenin signaling pathway is a hallmark of a number of solid tumors. We analyzed the regulation of the Wnt/β-catenin pathway in acute lymphoblastic leukemia (ALL) and its role in the pathogenesis of the disease. We found that expression of the Wnt inhibitors sFRP1, sFRP2, sFRP4, sFRP5, WIF1, Dkk3, and Hdpr1 was down-regulated due to abnormal promoter methylation in ALL cell lines and samples from patients with ALL. Methylation of Wnt inhibitors was associated with activation of the Wnt-signaling pathway as demonstrated by the up-regulation of the Wnt target genes WNT16, FZ3, TCF1, LEF1, and cyclin D1 in cell lines and samples and the nuclear localization of β-catenin in cell lines. Treatment of ALL cells with the Wnt inhibitor quercetin or with the demethylating agent 5-aza-2′-deoxycytidine induced an inactivation of the Wnt pathway and induced apoptosis of ALL cells. Finally, in a group of 261 patients with newly diagnosed ALL, abnormal methylation of Wnt inhibitors was associated with decreased 10-year disease-free survival (25% versus 66% respectively, P 〈 .001) and overall survival (28% versus 61% respectively, P = .001). Our results indicate a role of abnormal Wnt signaling in ALL and establish a group of patients with a significantly worse prognosis (methylated group).

Description: Introduction Graft versus host disease (GvHD) is the main cause of morbimortality after allogeneic stem cell transplantation (allo-SCT). Several single-nucleotide polymorphisms (SNPs) in in the promoter region of cytokine genes have shown to alter their expression and are therefore associated with donor-recipient alloreactivity and, ultimately, with SCT outcome. Interleukin 17 (IL-17) is secreted by CD4+ T-cells and has been implicated in the pathogenesis of various autoimmune diseases but its importance in SCT is not well-known. Objective To analyse the influence of IL-17A SNP genotypes on the risk and severity of GvHD and other complications after HLA-identical allo-SCT. Patients and Methods Genomic DNA obtained from peripheral blood samples belonging to 546 patients and their HLA-identical sibling donors (Table 1) included in the DNA Bank of the Spanish Group for Hematopoietic Stem Cell Transplantation (GETH). Genotyping of the polymorphisms of interest, rs8193036 (-737C〉T), rs2275913 (-197G〉A), rs3819024 (-444A〉G), rs4711998 (-877A〉G), were performed by multiplex primer extension followed by mass spectrometry (MALDI-TOF; Sequenom MassArray). Results Genotype frequencies are shown in Table 2 and the association between IL-17A genotypes and complications after allo-SCT are shown in Table 3. Patients transplanted from donors harboring genotype CC for the SNP rs8193036 show increased risk of grade III-IV acute GvHD (7/26 vs 47/397, p=0.035) and of grade II-IV acute GvHD (13/26 vs 133/409, p=0.048). Patients transplanted from donors harboring allele A in the SNP rs4711998 show increased risk of extensive chronic GvHD (53/161 vs 43/177, p=0.045). Relapse rate was not related with IL-17A SNP genotypes. Finally a higher risk of toxicity-related mortality (TRM) was observed in patients transplanted from donors harboring allele A for SNP rs2275913 (78/293 vs 46/227, p=0.048), donors harboring allele G for SNP rs3819024 (78/279 vs 46/242, p=0.011) and donors harboring allele A for SNP rs4711998 (68/250 vs 55/229, p=0.044). Conclusions IL-17A SNP genotyping might be useful to anticipate complications after sibling HLA-identical allo-SCT and, therefore, to improve the clinical management of transplanted patients. This results further support the idea of a genetic predisposition to certain complications after allo-SCT. Paper presented on behalf of the GvHD/Immunotherapy committee of the Spanish Group for Hematopoietic Transplantation (GETH). Disclosures: No relevant conflicts of interest to declare.

Description: Abstract 1154 Poster Board I-176 INTRODUCTION Glutathione-S-transferase (GST) M1 and T1 are multifunctional enzymes involved in the metabolism of environmental carcinogens and chemotherapeutic drugs. The immunogenic activity of these enzymes and their association with graft rejection has been widely proved in solid organ transplantation. In this study we examined whether genetic variability (absence versus presence of the gene in donor/recipient pairs) could be related to acute graft versus host disease (aGvHD) in patients undergoing myeloablative allogeneic hematopoietic stem cell transplantation (alloHSCT) from related donor (RD). PATIENTS AND METHODS We evaluated 64 patients with acute leukemia (34 AML and 30 ALL) undergoing alloSCT and receiving myeloablative conditioning (MAC), with a minimum follow-up of 100 days. Donors were HLA-identical siblings in all cases, except in 2 presenting only a single HLA disparity. As source of HSCs, bone marrow progenitors were used in 25 patients (40%) and peripheral blood progenitors in 39 (60%). Total body irradiation (TBI) was used for conditioning treatment in 18 cases (28%). GvHD prophylaxis consisted of a short-term combination of Cyclosporine and Methotrexate. Presence in homozygous or heterozygous (positivity) or absence (negativity) of GSTM1/T1 genes were determined by real-time PCR. A Chi-square test was used to evaluate qualitative variables and non-parametric tests for quantitative variables. The Cox proportional-hazard model was applied to multivariate analysis. RESULTS GSTT1 and GSTM1 positivity was observed in 73 and 47% of patients, respectively, and in 72 and 46% of donors, respectively. Nineteen of 64 patients (30%) presented grade II-IV aGvHD. The incidence of grade II-IV aGVHD in GSTM1-positive patients was 79% versus 21% in GSTM1-negative patients. In univariate analysis, only GSTM1 positive patients developed grade II-IV aGvHD (p=0.001). In multivariate analysis, GSTM1 positivity was the only variable significantly associated with the appearance of grade II-IV aGvHD (p=0.002). No significant association was detected between GSTT1 genetic variability and the incidence of aGvHD. We found no significant difference in patients overall survival in relation to GSTM1 and GSTT1 genetic variability. CONCLUSIONS GSTM1-positive recipients develop more likely grade II-IV aGvHD, independently of other known risk factors. GSTM1 gene determination (homozygous or heterozygous) could be used to assess the aGvHD risk in allogeneic hematopoietic stem cell transplantation. Disclosures No relevant conflicts of interest to declare.

Description: Increasing mixed chimerism (MC) predicts morphological relapse after stem cell transplantation (SCT) in patients with acute leukemia. Early treatment of increasing MC reduces the onset of relapse and improves survival. However, conventional methods for chimerism analysis fail to detect MC prior to a considerable number of relapses. We have tested a new approach for chimerism follow-up, based on amplification by real-time quantitative PCR (rtq-PCR) of null alleles and insertion/deletion (indel) polymorphisms, and compared it with conventional variable number of tandem repeats (VNTR)-PCR. Four null alleles: GSTM1, GSTT1, RhD and SRY, and 10 indels: Xq28, rs4399, DCP1, R271, FVII, THYR, MID-1039, MID-1335, MID-1385, MID-2062, were quantified by rtq-PCR using allele-specific primers and probes (LyghtCycler technology). Sensitivity studies (by mixture of positive and negative DNA), and intra- or inter-assay variability experiments were performed. All markers showed high sensitivity (at least 0.01%) and reproducibility. Accuracy of the method was also confirmed by dilution of positive in negative cells with subsequent DNA extraction and rtq-PCR quantification. Donor/host informativity (presence of the sequence in the recipient and absence in the donor) was tested retrospectively in a series of 68 acute leukemia patients, and at least one informative marker was obtained in 85.3% of donor/host pairs. Chimerism follow-up was performed on peripheral blood (PB) and bone marrow (BM) samples obtained after SCT. In non-relapsed patients, PB host chimerism values progressively descended from transplantation until reaching donor complete chimerism (CC); conversely, BM chimerism decreased but did not reach CC more than 3 years after SCT. From 18 relapses evaluable with rtq-PCR, 16 (89%) showed increasing chimerism in PB samples prior to relapse; by contrast, only 73% of such relapses were preceded by increasing MC in BM. When compared to VNTR, rtq-PCR predicted a significantly higher number of relapses (89% vs 42%) and anticipated them earlier (median of 56 vs 38 days). In summary, rtq-PCR determination of null alleles and indels constitutes a new validated simple procedure to monitor hematopoietic chimerism after SCT. It improves the predictive results obtained with conventional VNTR-PCR, and is specially useful when PB samples are analyzed.

Description: Background: Prior clinical trials demonstrated that 33-61% of patients with CML maintain disease control following TKI discontinuation in the 1st line and beyond (Thielen, Eur J Cancer. 2013; Mahon, Lancet Oncol. 2010; Hochhaus, ASCO 2016; Hughes, ASCO 2016; Imagawa, Lancet Haematol. 2015). Patients who relapsed after discontinuation regained major molecular response (MMR) upon retreatment. Dasatinib, a 2nd generation TKI, induces fast and deep molecular responses, making it an effective option for patients in view of a possible TFR. Here, we report interim results from the phase 2 DASFREE study, investigating TFR with dasatinib in the 1st and 2nd line settings. Methods: DASFREE (CA180-406/NCT01850004) is a phase 2 open-label, single-arm study in adults with CML-CP who were on dasatinib for ≥2 yr as 1st line or subsequent therapy, had confirmed dasatinib-induced DMR (defined as MR4.5, BCR-ABL1 ≤0.0032% [IS]) for ≥1 yr prior to enrollment, and achieved a 1-log reduction in BCR-ABL1 from baseline within 3-6.5 mo of starting dasatinib. Prescreening for MR4.5 was done at a local lab, with confirmation at a central lab twice over a 3-mo interval prior to dasatinib discontinuation (screening phase). BCR-ABL1 was monitored centrally after treatment discontinuation every mo in the 1st yr, then every 3 mo. If loss of MMR occurred, patients resumed dasatinib at the previous dose. The primary endpoint is MMR rate at 1 yr after dasatinib discontinuation. Secondary endpoints include kinetics of loss of response, event-free survival (EFS; no loss of MMR), relapse-free survival (RFS; no loss of MMR, complete cytogenetic response, or complete hematologic response, or progression to accelerated/blast phase CML), progression-free survival, and overall survival. Exploratory analyses include frequency of adverse events (AEs) after discontinuation and during dasatinib treatment, and molecular response rates after reinitiating dasatinib. All patients will be followed for up to 5 yr. This analysis reflects a planned interim assessment of patients followed for TFR for ≥1 yr. Results: Currently, 71 patients are enrolled out of 79 planned. Thirty patients (14 male; median age 51 yr [range: 29-76]; Sokal scores: 60% low, 27% intermediate, 3% high, 10% unknown) followed for ≥1 yr after dasatinib discontinuation were included in this interim analysis. MMR rate at 1 yr following discontinuation was 63% (95% CI: 46-81). EFS rate at 1 yr following discontinuation was 63% (95% CI: 44-78; Figure). RFS rate at 1 yr following discontinuation will be presented. Eleven of 30 patients lost MMR, with a median time to loss of MMR of 4 mo (range: 1-8). Median time on dasatinib prior to discontinuation was 40 mo (range: 26-114) for patients who lost MMR and 55 mo (range: 31-87) for patients who retained MMR. Eleven patients who lost MMR restarted dasatinib therapy: 10 regained MMR, and 1 patient chose to restart therapy at a nonstudy site, discontinued study, and was lost to follow-up. The kinetics of molecular relapse, the number of patients that regained DMR, and the time to regain MMR or DMR will be presented. No transformation events or deaths were observed at the time of this analysis. After discontinuation, 5 patients had musculoskeletal AEs; in 2 patients (with 3 events) these AEs were attributed to withdrawal from dasatinib by investigators. Additional AEs following discontinuation included hypertension (17%) and skin disorders (13%). For patients who restarted dasatinib, AEs were consistent with the known safety profile, and none of the on-treatment AEs resulted in discontinuation. Conclusions: This interim analysis of the first 30 patients enrolled in DASFREE demonstrated patients with dasatinib-induced DMR treated in the 1st and 2nd line had high rates of success at maintaining remission after treatment was discontinued (63% MMR and EFS at 1 yr), and there was rescue of molecular response in all patients once dasatinib was reinitiated. There is a suggested correlation between time on dasatinib prior to discontinuation and maintaining MMR. Dasatinib withdrawal appears to be tolerable, as there was a low incidence of withdrawal symptoms. These data build upon the growing body of evidence supporting the feasibility of TFR in patients with CML-CP and demonstrate that with frequent monitoring of BCR-ABL1, patients treated with dasatinib in the 1st and 2nd line can successfully discontinue treatment. Longer-term follow-up is ongoing. Figure Figure. Disclosures Shah: Bristol-Myers Squibb, ARIAD, Pfizer, Daiichi-Sankyo, Plexxikon: Research Funding. Paquette:Bristol-Myers Squibb: Research Funding, Speakers Bureau; Novartis: Research Funding, Speakers Bureau; Ariad: Research Funding, Speakers Bureau. Müller:Ariad, BMS, Novartis, Pfizer: Honoraria; Ariad, BMS, Novartis, Pfizer: Consultancy; Institute for Hematology and Oncology, IHO GmbH: Employment, Equity Ownership. Saussele:Novartis, BMS, Ariad, Pfizer: Honoraria; Novartis, BMS: Research Funding. Garcìa-Gutiérrez:Novartis, BMS, Ariad and Pfizer: Consultancy; Novartis, BMS, Ariad and Pfizer: Research Funding. Nicolini:Ariad: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Consultancy, Honoraria. Mauro:ARIAD: Consultancy, Honoraria; BMS: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria. Mahon:Pfizer: Honoraria; BMS: Honoraria; Novartis: Honoraria, Research Funding; Ariad: Honoraria. Rea:Novartis: Honoraria; Ariad: Honoraria; Pfizer: Honoraria; BMS: Honoraria. Martin-Regueira:Bristol-Myers Squibb: Employment. Subar:Bristol Myers-Squibb: Employment. Li:Bristol-Myers Squibb: Employment. Lipton:BMS: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; Ariad: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding.

Description: Promoter hypermethylation plays an important role in the inactivation of cancer-related genes. This abnormality occurs early in leukemogenesis and seems to be associated with poor prognosis in acute lymphoblastic leukemia (ALL). To determine the extent of hypermethylation in ALL, we analyzed the methylation status of the CDH1, p73, p16, p15, p57, NES-1, DKK-3, CDH13, p14, TMS-1, APAF-1, DAPK, PARKIN, LATS-1, and PTEN genes in 251 consecutive ALL patients. A total of 77.3% of samples had at least 1 gene methylated, whereas 35.9% of cases had 4 or more genes methylated. Clinical features and complete remission rate did not differ among patients without methylated genes, patients with 1 to 3 methylated genes (methylated group A), or patients with more than 3 methylated genes (methylated group B). Estimated disease-free survival (DFS) and overall survival (OS) at 11 years were 75.5% and 66.1%, respectively, for the nonmethylated group; 37.2% and 45.5% for methylated group A; and 9.4% and 7.8% for methylated group B (P 〈 .0001 and P = .0004, respectively). Multivariate analysis demonstrated that the methylation profile was an independent prognostic factor in predicting DFS (P 〈 .0001) and OS (P = .003). Our results suggest that the methylation profile may be a potential new biomarker of risk prediction in ALL.

Description: Abstract 468 AML is worldwide the most frequent indication for allo-SCT. This is most likely due to the curative potential of the graft versus leukemia (GVL) effect associated with the procedure. Unfortunately, GVL and GVHD are intimately linked. Thus, it is important to identify markers predictive of severe GVHD, to balance the risk of this complication and the risk of relapse in a particular AML patient. The innate immune system, as the initial regulator of the inflammatory response, mediates an important role in these reactions. After conditioning regimen, toll-like receptors initiate the innate inflammatory response by activating intracellular signaling cascades that converge on the activation of NF-κB and interferon regulatory factor-3 (IRF3). IRF3 activation in bone marrow derived dendritic cells (DCs) results in natural killer (NK) cell activation inducing an anti-tumor NK response. We hypothesized that genetic variability in IRF3 in either the donor or the recipient could impact on the degree of the inflammatory response and on GVHD and GVL effect allo-SCT. We analysed the effect of two frequent single nucleotide polymorphisms (SNPs) in IRF3 (rs7251 and rs2304205), which are inherited in a haplotype, on the GVHD and GVL in 249 patients diagnosed with AML and submitted to HLA-identical sibling allo-SCT. Those patients with a donor carrying dominant GG gene variant in rs7251 (45% of the donors) had, as compared to GC (44%) and CC (11%) variants, lower aGVHD III-IV incidence (4% vs 11% vs 27%; p=0.0078) (Figure 1A), higher relapse incidence (49% vs 35% vs 26%; p=0.018) (Figure 1B), and lower TRM (7% vs 24% vs 18%; p=0.0065). This clinical impact on severe aGVHD, relapse, and TRM was retained at multivariate analysis. Further, GG gene variant in rs7251 when present in the patient was also associated with lower aGVHD III-IV incidence (4% vs 13% vs 24%; p=0.009), higher relapse incidence (50% vs 34% vs 31%; p=0.014), and with a trend for a lower TRM (9% vs 19% vs 23%; p=0.064). Patients carrying AA dominant gene variant in rs2304205 in IRF3 presented a higher relapse incidence than the rest of genotypes (50% vs 39% vs 18%, p=0.0068). However, this impact was not retained at multivariate analysis. Functional studies in 180 healthy individuals showed that after stimulation of peripheral blood with cytomegalovirus (CMV) peptides, GG gene variant in rs7251 presented lower IFN-γ serum production than the rest of individuals, and GG gene variant was associated with lower number of IFN-γ producing mature NK cells, lower number of cytotoxic NK cells against K562 cell line and lower proliferation of T cells after antigen presentation by DCs. In conclusion, we show that a particular gene variant in IRF3 in the donors is associated with a low incidence of severe aGVHD and high incidence of relapse in AML patients submitted to allo-SCT. This finding could be explained by its effect in the inflammatory and adaptive immune response, with lower IFN-g production, lower lymphocyte proliferation after antigen presentation by DCs and lower mature NK cell response. Thus, these results suggest that, if possible, when transplanting an AML patient with a low risk of relapse it might be preferable to select a donor harbouring GG in rs7251 in IRF3, and when transplanting an AML patient with a high risk of relapse after the transplant it might be preferable to consider select a donor GC or CC in rs7251 in IRF3. Disclosures: No relevant conflicts of interest to declare.

Description: Introduction: Early responses to tyrosine kinase inhibitors (TKIs) are associated with improved long-term outcomes in patients with chronic myeloid leukemia in chronic phase (CML-CP), and guideline recommendations support the achievement of major molecular response (MMR) at 18 months as a therapeutic goal in CML treatment. Dasatinib is a first-line (1L) treatment option for patients with CML-CP, and long-term results from the DASISION study have demonstrated that patients on dasatinib achieved faster, deeper, and more durable molecular responses than patients on imatinib (Cortes J et al. J Clin Oncol 2016). Earlier reports have shown that obesity may increase the risk of developing CML (Strom SS et al. Cancer Epidemiol Biomarkers Prev 2009) and that patients with a high body mass index (BMI; 〉 25 kg/m2) at diagnosis who receive 1L imatinib have a significantly longer median time to response and a reduced rate of MMR compared with patients with a normal BMI (〈 18.5-25 kg/m2; Breccia M et al. Cancer Lett 2013). In this exploratory post hoc analysis of the phase 3 DASISION trial (NCT00481247), we further investigated the association of high BMI with treatment responses with 1L TKIs. Methods: DASISION was a multinational, open-label, phase 3 trial of dasatinib versus imatinib for newly diagnosed CML-CP. Patients were randomized to receive 100 mg dasatinib (n = 259) or 400 mg imatinib (n = 260) once daily. Response outcomes were retrospectively stratified on the basis of two BMI categories: high (≥ 25 kg/m2) and normal (〈 25 kg/m2). Median time to response was estimated using Kaplan-Meier analysis; Cox proportional hazard models and log-rank tests were stratified by Hasford scores. Molecular response rates were compared using Cochran-Mantel-Haenszel tests (stratified by Hasford scores). P values are descriptive and unadjusted for multiple comparisons. Results: In total, 109 patients with a high BMI and 147 patients with a normal BMI were treated with dasatinib, and 107 patients with a high BMI and 147 patients with a normal BMI were treated with imatinib. Baseline characteristics were balanced within BMI subgroups and are listed in the table below (Table). Median time to complete cytogenetic response (CCyR) was significantly shorter with dasatinib versus imatinib in patients with a high BMI (3.1 vs 6.1 months; P 〈 0.0001). MMR was also achieved faster in patients with a high BMI who were treated with dasatinib versus imatinib (median time 9.2 vs 27.6 months; P 〈 0.0001; Figure). More patients with a high BMI treated with dasatinib achieved MMR compared with those treated with imatinib (79.8% vs 59.8%; P = 0.0004). Likewise, 54.1% of patients with a high BMI achieved MR4.5 with dasatinib, compared with 34.6% with imatinib (P = 0.0013). In the normal BMI group, median time to CCyR (5.6 vs 6.0 months; P = 0.1055) and MMR (18.0 vs 21.5 months; P = 0.4095) was faster for dasatinib versus imatinib, and more patients on dasatinib versus imatinib achieved MMR (73.5% vs 67.3%; P = 0.3335) and MR4.5 (36.7% vs 33.3%; P = 0.6344). Although these results were numerically better with dasatinib, the differences were not statistically different. A graphical exploratory analysis suggested that there was no difference in exposures across BMI subgroups with respect to dasatinib. However, imatinib exposure data were not available to make comparisons across the BMI subgroups. There was no major difference in the previously reported adverse event profiles between treatment groups when assessed based on BMI. Any-cause pleural effusion occurred more frequently with dasatinib (34.3% [high BMI] and 24.5% [normal BMI]) compared with imatinib (0% [high BMI] and 2.0% [normal BMI]). Additional analyses are being planned to address the role of any potential confounders (eg, Hasford risk scores). Conclusions: In this exploratory post hoc analysis, patients with a high BMI treated with dasatinib demonstrated a significantly faster time to response compared with imatinib, with an increased percentage of patients also achieving MMR and MR4.5 at 5 years. However, these differences were not apparent in patients with a normal BMI. Although these findings highlight the potential role of BMI in affecting treatment responses to TKIs, additional validation of these findings is necessary to define the overall impact of BMI as a prognostic factor for patients with CML-CP. Study support: BMS. Writing support: Jane Cheung, Caudex, funded by BMS. Disclosures Breccia: Bristol-Myers Squibb, Celgene, Incyte, Novartis, Pfizer: Honoraria. Cortes:Bristol-Myers Squibb: Consultancy, Research Funding; Takeda: Consultancy, Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Daiichi Sankyo: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria, Research Funding; Astellas Pharma: Consultancy, Honoraria, Research Funding; Jazz Pharmaceuticals: Consultancy, Research Funding; Sun Pharma: Research Funding; Immunogen: Consultancy, Honoraria, Research Funding; Merus: Consultancy, Honoraria, Research Funding; Forma Therapeutics: Consultancy, Honoraria, Research Funding; Biopath Holdings: Consultancy, Honoraria; BiolineRx: Consultancy. Shah:Bristol-Myers Squibb: Research Funding. Saglio:Celgene: Consultancy; Jansen: Consultancy; Pfizer: Consultancy; BMS: Consultancy; Novartis: Consultancy; Ariad: Consultancy; Incyte: Consultancy. Le Coutre:Novartis: Honoraria, Speakers Bureau; Pfizer: Honoraria, Speakers Bureau; Bristol-Myers Squibb: Honoraria, Speakers Bureau; Incyte: Honoraria, Speakers Bureau. Brun:Bristol-Myers Squibb: Employment. DeGutis:Bristol-Myers Squibb: Employment, Other: Stock options. Sy:Bristol-Myers Squibb: Employment, Equity Ownership. Jabbour:AbbVie: Consultancy, Research Funding; Takeda: Consultancy, Research Funding; BMS: Consultancy, Research Funding; Adaptive: Consultancy, Research Funding; Amgen: Consultancy, Research Funding; Cyclacel LTD: Research Funding; Pfizer: Consultancy, Research Funding.

Description: Backgroung: In chronic myeloid leukemia (CML) patients, 3-month BCR-ABL1 levels ≤10% measured using conventional RQ-PCR (IS) have consistently been correlated with further outcomes. Monitoring molecular responses using the Xpert BCR-ABL1 MonitorTM PCR system has demonstrated an optimal correlation with standardized RT-qPCR (IS), however, it is not known whether both methods are also equivalent when measuring BCR-ABL1 levels higher than 10%. We previously showed how the cutoff of 10% was not correlate with subsequent responses when using Xpert BCR-ABL1 in a cohort of 125 consecutive CML patients treated with imatinib (58%) and second generation TKI (2GTKI) (42%) as frontline treatment. By contrast, by using a receiver operating characteristic curve, a new cutoff of 1.5% was correlated with probabilities to achieve complete cytogenetic response (CCR) and major molecular response (MMR. The aim of this study is to validate the new cutoff of 1.5% at 3 months in patients treated with second generation 2GTKI. Methods: We have studied 57 new consecutive CML-CP patients treated 2GTKI from from Andalusian CML Group Registry. BCR-ABL1 transcript quantification was performed using the automated method Xpert BCR-ABL1 Monitor™, Cepheid, aligned to the 0.1% BCR-ABL1 ratio according to the standards of the World Health Organization. The samples were not centrally collected. All analyses were performed on an intention-to-treat basis unless otherwise stated. The proportions of patients who achieved MMR and CCyR after first-line treatment for 1 year and the response at 3 months were compared by applying Pearson's chi-square test or Fisher's exact test The study was approved by the Ethics Committee. Results: The median age at diagnosed was 48 years (18-74). The ratio of men to women was 59/41, and the risk groups according to Sokal Score were 48%, 30% and 22% for low, intermediate and high risk, respectively. Median follow up was 38 months (3-56). First-line treatment consisted of nilotinib and dasatinib in 58% and 42% of patients, respectively. Overall, the probability of achieving CCyR and MMR at 12 months was 92% (48/52) and 82% (39/47), respectively. Ten patients (17%) required treatment changes as a result of resistance (n=3), not achieving MMR (n=3) or intolerance (n=4). No patients progressed to advanced phases, and only 1 patient died during follow-up (not CML related). The overall median value of BCR-ABL1 at 3 months was 0.16%. Consistent with the original cohort of patients treated with first-line 2GTKI, all patients achieved a BCR-ABL1 level ≤10% at 3 months; therefore, this cutoff did not predict further evolution. We classified this new cohort based on the new cutoff observed in the primary population (BCR-ABL1 level at 3 months ≤1.5%); 77% of patients achieved BCR-ABL1 levels ≤1.5%, whereas 23% of patients did not. This cutoff also predicted the probability to obtain MMR by 12 months (91% vs. 44% (p=0.025). Conclusions: We have shown that when using the current version of GeneXpert, a BCR-ABL1cutoff of 10% at 3 months may underestimate the probability of not achieving an ulterior optimal response. We have shown that a new cutoff of 1.5% at 3 months can better identify patients with lower risk to achieve an optimal response at 12 months. This information should be taken into considerations when using this practical and widespread platform to monitor CML patients. Disclosures García Gutiérrez: Ariad: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; BMS: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding. Ramirez:Bristol-Myers-Squibb: Honoraria; Janssen: Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria; Roche: Honoraria. Steegmann:BMS: Honoraria, Other: Research funding for the Spanish CML Group; Pfizer: Honoraria, Other: Research funding for the Spanish CML Group; Novartis: Honoraria, Other: Research funding for the Spanish CML Group; Ariad: Honoraria, Other: Research funding for the Spanish CML Group.

Description: Introduction. Graft versus host disease (GvHD) is the main cause of morbimortality after allogeneic stem cell transplantation (allo-SCT). Several single-nucleotide polymorphisms (SNPs) in cytokine genes have shown to influence gene expression and are therefore associated with donor-recipient alloreactivity and, ultimately, with SCT outcome. Interleukin 1 (IL1) is a proinflammatory cytokine that induces the production of cytokines and chemokines and plays an important role in the inflammatory processes. IL1 is involved in various cellular functions, including cell proliferation, differentiation, and apoptosis. The IL1 family consists of two biologically actives forms (IL1A and IL1B). Several polymorphisms of these genes have been implicated in the pathogenesis of autoimmune diseases, however, their importance in SCT is not well-known. Objective To investigate the relationship between 4 SNPs in IL1A and IL1B genes and the susceptibility to the development of GvHD and other complications after HLA-identical allo-SCT. Patients and methods Genomic DNA obtained from peripheral blood samples belonging to 509 patients and their HLA-identical sibling donors (Table 1) included in the DNA Bank of the Spanish Group for Hematopoietic Stem Cell Transplantation (GETH). One SNP, rs1800587 (-889 C〉T), in the promoter region of the IL1A gene and three SNPs in the IL1B gene (two in the promoter region rs16944 (-511C〉T), rs1143627 (-31 T〉C) and one in exon 5 rs1143634 (+3954 C〉T) were genotyped by multiplex primer extension followed by mass spectrometry (MALDI-TOF; Sequenom MassArray). Univariate and multivariate regression analysis were performed using Cox regression in the presence of competing risks except for chronic GvHD for which we used logistic regression model. All variables with p≤0.10 according to univariate analysis were included in the multivariate analysis. For multivariate analyses, p values were two sided and the outcomes were considered to be significant for p