ALBERT

Description: Abstract 3654 Background: Diffuse large B-cell lymphoma (DLBCL) is a heterogeneous entity, showing affected patients a highly variable outcome. The improvement in survival gained with the addition of rituximab to CHOP chemotherapy (R-CHOP) led to re-define the international prognostic index (IPI). The new index, known as revised IPI (R-IPI), showed to be simpler as it groups the patients in only 3 risk groups. However, the effect of prior rituximab-therapy upon the usefulness and significance of previously recognized prognostic factors on patients relapsed or refractory and receiving subsequent treatment with rituximab plus chemotherapy in DLBCL remains unexplored. Biological parameters, including expression of Bcl-6, Bcl-2, p53 and MUM-1 have been described as IPI-independent prognostic factors. Objectives: The objective of this study was to evaluate the benefit of the R-IPI to predict the outcome of DLBCL patients at the relapse time following a front line treatment with chemotherapy and rituximab. We also aimed to establish in this population the relationship between immunohistochemical expression of biological parameters and outcome. Patients and methods: this was a multicentric, observational, post-authorization and cross-sectional study (ClinicalTrials.gov identifier: NCT01369784). Inclusion criteria were: patients with age ≥ 18 years with DLBCL refractory/relapsed after first line treatment with rituximab, with or without transplantation. Patients must have finished a rescue treatment including rituximab. Written informed consent was obtained from participants. When the data of the biopsies at diagnosis and relapse were available, immunohistochemical results of bcl-2, bcl-6, p53 and MUM-1 were obtained. Results: 152 patients were included (146 evaluables) with a median age of 58 years. At LDBCG diagnosis 48% had 〉 1 extranodal localization (29% had bone marrow disease), and 30% had ECOG 2 or greater. Eighty-one percent presented stages III or IV and 72% had elevated LDH. Three percent had very good prognosis R-IPI, 69% good prognosis R-IPI and 27% poor prognosis R-IPI. Most patients received R-CHOP as first line therapy. Overall response rate was 79% (40% complete remission). Relapse was confirmed with biopsy and histological study in 55 patients. At relapse 31% presented 〉 1 extranodal localization, 30% ECOG 2–4, 64% stages III-IV and 72% elevated LDH. R-IPI prognostic groups distribution at relapse were as follows: 8% very good, 75% good and 27% poor. R-ESHAP and R-GEMOX were the two more used rescue therapies resulting in 60% overall response rate (31% complete remission). R-IPI at relapse was significantly associated (p 〈 0,05) with overall response rate following R-chemotherapy rescue therapy. None of the immunohistochemical parameters analized correlated with rescue therapy results. Conclusions: This is the largest reported series analizing R-IPI in DLBCL at relapse/refractory in patients receiving R-chemotherapy. In this series of patients R-IPI calculated at the relapse time was the only prognostic factor capable of predicting the overall response to the second line of treatment. Thus R-IPI prognostic score is a simple and useful predictor for outcome in DLBCL at relapse/refractory Disclosures: No relevant conflicts of interest to declare.

Description: Acute Myeloid Leukemia (AML) is the most common type of acute leukemia in adults and the second in children. The overall survival is less than 35% and 60% for adults and children respectively. Activating mutations of FLT3 are now recognized as the most common molecular abnormality in this disease, and the poor prognosis of patients harboring these mutations renders FLT3 an obvious target of therapy. Although different tyrosine kinase inhibitors (TKI) have been used for this purpose, the ability of these drugs to extend progression-free and overall survival in this patient population is limited by drug resistance. This strategy could be improved by rationally combining TKIs with other agents. In this work, we have explored by phosphoproteomics the alternative pathways activated after TKI treatment in vitro and ex vivo. The phosphoproteome profile of the bone marrow from a FLT3-AML patient before and after TKI treatment, studied by LC-MSMS after IMAC enrichment, suggested the activation of Ras-Raf-MEK-ERK1/2 pathway as a possible mechanism for TKI resistance, which could be avoided by dual inhibition using the MEK inhibitor trametinib. Therefore, we characterized the effect of trametinib in combination with the TIK pazopanib and sorafenib by the in vitro cell viability assay using WST8in the FLT3-ITD AML cell line MOLM13. As it is presented in figure 1a, trametinib showed an IC50 value in the low-nanomolar range (5.4 nM) and this MEKI produced a strong synergy (0.5

Description: Introduction The Wilms' tumor 1 (WT1) gene, located on chromosome 11p13, encodes a transcription factor with both oncogene and tumor suppressor functions. WT1 is reportedly overexpressed in 90% of patients with acute myeloid leukemia (AML) and thus can be used for minimal residual disease (MRD) monitoring by quantitative RT-PCR. The aim of the present study was to analyze the usefulness of WT1 as a marker for MRD in AML after chemotherapy and as a predictor of relapse and survival. Patients and Methods This retrospective and multicentric study included 114 patients with WT1-overexpressed AML (Table 1). Quantitative assessment of WT1 transcript levels was performed by quantitative RT-PCR in 283 bone marrow (BM) samples at diagnosis, post-induction and post-consolidation. WT1 gene expression was calculated by relative quantification using the normalized ratio of the target gene (WT1) related to a reference gene (GUS) and using cell line K562 as calibrator. Inter-laboratories methodological standardization was accomplished through a pilot study with 10 BM donor samples, 20 BM patient samples and commercial WT1 plasmids (ProfileQuant Kit, Ipsogen-Qiagen). Results No significant differences in WT1 gene expression (cycle threshold, Ct) were observed between different laboratories in the pilot study. The cut-off value of WT1 over-expression in BM was established in 0.55% (median+2SD values from healthy donors). Median WT1 expression in patient samples at diagnosis was 29.5% (range, 2-1220). Differential expression at diagnosis was not correlated with age, sex, leukocytes, karyotype (risk), however a higher expression in patients with AML-M1 and AML-M2 subtypes as well as patients with mutant NPM1 and/or ITD-FLT3 was observed. Most patients (88.6%; 101/114) received intensive chemotherapy as induction treatment. After induction, 80.2% (81/101) of patients had available WT1 data, of which 23.45% (19/81) were positive. In addition, 79.8% (91/114) received intensive treatment during consolidation. WT1 results were available for 75.5% (66/91), of which 22.7% (15/66) were positive. Post-induction WT1 positivity was correlated with a higher cumulative incidence of relapse (CIR; 2 years 76% vs. 28.2% p=0.002) and a lower overall survival (OS; 2 years, 44.9% vs. 78.2% p=0.022; Figure 1a,b). Similar results were obtained when patients intensified with allogeneic stem cell transplantation (allo-SCT) were excluded from the analysis: higher CIR (2 years 88.9% vs. 32.5%; p=0.005) and lower OS (40% vs. 76.2% p=0.17). Post-consolidation WT1 positivity was correlated with a trend to a higher CIR (2 years 60.3% vs. 41.4% p=0.21) and a lower OS (2 years 44.9% vs. 66% p=0.09; Figure 1c,d). Statistically significant results were obtained after consolidation when patients treated with allo-SCT were excluded from the analysis: higher CIR (2 years 100% vs. 40.1% p=0.005) and lower OS (2 years 20% vs. 66% p=0.003). Conclusions WT1 is a useful marker for MRD in AML patients undergoing chemotherapy (induction and consolidation) which allows anticipation of relapse and survival. Post-induction results were a strong risk factor of relapse and survival in all patients, including those intensified with allo-SCT. By contrast post-consolidation results are especially relevant in the group of patients not treated with allo-SCT. Intensification with allo-SCT overcomes the poor prognosis derived from positive post-consolidation WT1 results. Paper presented on behalf of the Hematological Molecular Biology Group (GBMH) of the Spanish Society of Hematology (SEHH). Disclosures: No relevant conflicts of interest to declare.

Description: Abstract 4478 Background: The optimal therapy after transformation of follicular lymphoma into diffuse large B-cell lymphoma (DLBCL) is unknown. Most of retrospective registry data and phase II studies suggest a potential benefit of high-dose therapy and autologous transplantation (HDT-ASCT) for patients with transformed lymphoma (TL). Addition of rituximab to CHOP chemotherapy could improve survival in TL. However, the effect of prior rituximab-based therapy upon the efficacy of subsequent autologous stell cell transplantation (ASCT) in TL is still unknown. Patients and methods: We have identified the patients with follicular lymphoma who developed confirmed histological transformation to DLBCL treated with HDT-ASCT included in the Grupo Español de Linfomas/Trasplante Autólogo de Médula Osea (GEL-TAMO) Spanish registry between October 1994 and March 2011. Patients were divided into two groups, according to whether rituximab-based regimens were given (n = 28, ‘R+’ group) or not (n = 22, ‘R-’ group) at the time of transformation. Kaplan-Meier survival curves were estimated, and differences in survival curves between groups were assessed using the log-rank test. Results: Fifty patients (23 women) with a histological diagnosis of TL who underwent HDT-ASCT were included. Median age at transplantation was 55 years (range 32–70). Patients had received a median of 2 (range 1–5) chemotherapy regimens prior to ASCT. Median time from diagnosis of follicular lymphoma to transformation was 49 months (range 8–135). Age-adjusted International Prognostic Index (IPI) was 2 or 3 in 11 patients (22%). Disease status prior to ASCT was first complete remission in 4 patients (8%), second CR in 56% and active diseasein 14%: sensitive disease in 11 (22%) and refractory disease in 3 (6%) patients. Conditioning regimen consisted of BEAM in 92% of patients, BEAC in 4%, and cyclophosphamide /TBI in 4%. With a median follow-up of 61 months, estimated overall survival (OS) and progression-free survival (PFS) at 5 years after ASCT were 56.5% and 51.3%, respectively. No patients died of transplant-related mortality. Thirteen patients experienced relapse or progression after HD-ASCT; nine of these patients have died because of disease progression. By multivariate analysis three variables significantly influenced both OS and PFS: number of regimens prior to ASCT, disease status at transplant and achievement of response after HD-ASCT. Age-adjusted IPI at transformation had significant influence only on OS. Patients who did not receive rituximab-based regimens had similar characteristics to patients who received rituximab at transformation. Patients in the R+ group had similar 5-year PFS (48.2% vs 48.4%, P = 0.359) and 5-year overall survival (OS) (66.4% vs 67.2%, P = 0.607) compared to patients in the R- group (Figures 1 and 2). Eight out of 28 “R+” patients had not received rituximab prior to transformation; these patients had better PFS (69% vs 38%, p = 0.912) and OS at 5 years (74.1% vs 54.5%) compared to the 20 patients who were treated with rituximab prior to transformation, but the difference did not reach statistical significance (p 〉0.1). Patients treated with rituximab-based regimens at any time prior HDT-ASCT had similar OS (70% versus 63.8% at 5 years, P = 0.697) and PFS (50% versus 44% at 5 years, P = 0.445) than patients who received chemotherapy alone before ASCT. Conclusion: Our results show that HDT-ASCT remains a valuable therapeutic choice for patients with histological confirmed TL since it allows a long-term disease control in a significant proportion of patients. The addition of rituximab to conventional chemotherapy after transformation does not appear to improve the outcomes of subsequent ASCT, although larger prospective studies are required. Disclosures: No relevant conflicts of interest to declare.

Description: Introduction: The Wilms’ tumor 1 (WT1) gene, located on chromosome 11p13, encodes a transcription factor. WT1 is overexpressed in 90% of patients with acute myeloid leukemia (AML) and thus can be used for minimal residual disease (MRD) monitoring by quantitative RT-PCR. The aim of the present study was to analyze the usefulness of WT1 as a marker for MRD quantification in AML after chemotherapy. Patients and Methods: This retrospective and multicentric study included 148 patients with WT1-overexpressed AML. Quantitative assessment of WT1 transcript levels was performed by quantitative RT-PCR in 370 bone marrow (BM) samples at diagnosis (148), post-induction (125) and post-consolidation (97). WT1 gene expression was calculated by relative quantification using the normalized ratio of the target gene (WT1) related to a reference gene (GUS) and using cell line K562 as calibrator. Inter-laboratories methodological standardization was accomplished through a pilot study with 20 BM donor samples, 20 BM patient samples and commercial WT1 plasmids (ProfileQuant Kit, Ipsogen-Qiagen). Results: No significant differences in WT1 gene expression (cycle threshold, Ct) were observed between different laboratories in the pilot study (kappa coefficient 〉0.7). The cut-off value of WT1 over-expression in BM was established for each laboratory (median+2SD values from healthy donors, data not shown). Median WT1 expression in patient samples at diagnosis was 38% (range, 2-850). Differential expression at diagnosis did not correlate with age, gender, leukocytes, karyotype (risk). However a significantly higher expression in patients with AML-M1 and AML-M2 subtypes as well as patients with mutant NPM1 and/or ITD-FLT3 was observed (p