ALBERT

Description: Abstract 1307 Background. Mutation of MYD88 gene has recently been identified in activated B-cell like diffuse B-cell lymphoma, and enhanced JAK STAT and NF-kB signalling pathways. Whole exome sequencing study in Waldenstrom macroglobulinemia (WM) suggested a high frequency of MYD88 L265P mutation in WM. Although the genetic background is not fully deciphered in WM, the role of NF-kB and JAK STAT pathways has been demonstrated in WM; which underlying mechanisms of deregulation remain to be elucidated. We aimed to analyze MYD88 mutation in exon 5 and to characterize the clinical significance of this genetic alteration in 67 WM. Method. 67 patients (42 males, 25 females) diagnosed with WM were included in this study, along with 9 patients with chronic lymphocytic leukemia (CLL), 4 multiple myeloma (MM) and 9 marginal zone lymphoma (MZL) were also studied. Patients were untreated at time of BM collection and gave informed consent prior to research sampling. Clinical features, immunophenotypic markers using flow cytometry (Matutes score panel, CD38, CD138, CD27, CD80), conventional cytogenetic, FISH and SNP array data (n = 46) were analysed. B cells from bone marrow and T cells from blood were isolated respectively using B cell isolation kit and Pan T isolation kit (Myltenyi Biotech). For DNA sequencing of exon 5 of MYD88, the exon 5 of MYD88 gene was amplified from genomic DNA by PCR. The purified PCR products were directly sequenced in both directions using BigDye® Terminator Cycle Sequencing Kit (Applied Biosystems, CA, USA) and analyzed on the Applied Biosystems 3130xl Genetic Analyzer. Data were analyzed with SeqScape software version 2.5 (Applied Biosystems). Results. MYD88 L265P mutation (MYDmut) was observed in 79% of patients, including homozygous mutation in two patients (3%). MYD88 mutation was not identified in T lymphocytes isolated from 4 WM patients that confirmed MYD88 mutation was acquired in the tumoral cells. We haven't observed any other mutation on exon 5. We then sought for other mechanisms of MYD88 gene alteration, such as copy number alteration (CNA) and copy neutral –loss of heterozygosity (CN-LOH) also considered as an acquired UPD (uniparental disomy) at MYD88 locus. We found an UPD at MYD88 locus in solely one patient (2%), and haven't identified any deletion at 3p22. On the contrary, we observed a gain on chromosome 3 at 3p22 locus (including MYD88 gene) in 7/57 (12%) patients. Taking together, we identified alteration of the MYD88 locus in 85% of patients with WM, by either gain-of-function mutation (79%) or CNA (12%). Interestingly, we found gain on chromosome 3 more frequently in the MYDwildgroup than in the MYDmutgroup (p=0.02). Twenty one percent of the patients with WM had no mutation of MYD (MYDwild), and were characterized with a female predominance, a splenomegaly, gain of chromosome 3 and CD27 expression. We did not observed difference in terms of survival according to the MYD88 mutation status. MYD88 mutation was not related to deletion 6q, gain of 4, deletion 11q, deletion 17p, deletion 13q14 in our study. Interestingly, deletion 7q, a frequent cytogenetic aberration in marginal zone lymphoma, was rare in our series (4/57; 7%) and was independent of MYD88 mutation status (2 in the MYDwild and 2 in the MYDmut) (p=ns). No MYD88 L265P mutation was observed in CLL and MM. In MZL, 1/9 patient without M monoclonal component had a MYDL265p mutation. Conclusion. These results confirm a high frequency of MYD88 L265P mutation in WM that may become a useful biomarker for diagnostic in WM and may help better understand the physiopathogeny of WM. Disclosures: No relevant conflicts of interest to declare.

Description: Imatinib (IM) at 400 mg daily is the first line therapy for newly diagnosed CML patients (pts); however, less than 50% of major molecular responses (MMR) are obtained at 12 months. To improve these results, we designed a phase III, multicenter, open-label, prospective randomized trial. The reference arm was IM 400 mg daily (n=159). The 3 experimental arms were IM 600 mg daily (n=160), IM 400mg daily in combination with Ara-C, (20 mg/m2/day, days 15–28 of 28-day cycles)(n=158) and IM 400mg in combination with Peg-IFN alfa-2a (Peg-IFN2a, 90 μg weekly) (n=159). Treatment was delivered at least 12 months or until treatment failure (disease progression) or major toxicity. The primary endpoint is the overall survival. Other endpoints are: rate and duration of hematologic and cytogenetic responses, major (MCyR) and complete (CCyR), molecular response (major molecular response ie MMR) and the tolerability. Using treatment allocation ratio 1.1.1.1, randomization was stratified according to Sokal risk groups. The current interim analysis of the first 636 patients (α=0.85%, β=10%) at 1 year from randomization was planned in order to select the best experimental arm for further comparison with IM 400. The increased dose of IM or a combination regimen would be considered as promising if it increased the 4 log reduction response rate by at least 20 percentage points, e.g. from 15% to 35%, with an acceptable tolerability. Evaluation of molecular response up to 12 months was centralized, blinded and calculated according to International score (IS). Pts were recruited between 9/2003 and 10/2007.[median age 51 yrs (18–82), 62% of pts were male; Sokal distribution was low risk 33%, intermediate risk 41% and 27% high risk]. Median follow-up is 36 months (range 8–57) at the time of analysis. Overall, at 3 months 86 % of pts achieved complete hematologic response. The MCyR, CCyR and MMR rates at 6 and 12 months are: IM-400 IM-600 IM-Ara-c IM-PegIFN *p〈 10−2 (overall); ** p

Description: Acquired molecular abnormalities (mutations or chromosomal translocations) of the RUNX1 transcription factor gene are frequent in acute myeloblastic leukemias (AMLs) and in therapy-related myelodysplastic syndromes, but rarely in acute lymphoblastic leukemias (ALLs) and chronic myelogenous leukemias (CMLs). Among 18 BCR-ABL+ leukemias presenting acquired trisomy of chromosome 21, we report a high frequency (33%) of recurrent point mutations (4 in myeloid blast crisis [BC] CML and one in chronic phase CML) within the DNA-binding region of RUNX1. We did not found any mutation in de novo BCR-ABL+ ALLs or lymphoid BC CML. Emergence of the RUNX1 mutations was detected at diagnosis or before the acquisition of trisomy 21 during disease progression. In addition, we also report a high frequency of cryptic chromosomal RUNX1 translocation to a novel recently described gene partner, PRDM16 on chromosome 1p36, for 3 (21.4%) of 14 investigated patients: 2 myeloid BC CMLs and, for the first time, 1 therapy-related BCR-ABL+ ALL. Two patients presented both RUNX1 mutations and RUNX1-PRDM16 fusion. These events are associated with a short survival and support the concept of a cooperative effect of BCR-ABL with molecular RUNX1 abnormalities on the differentiation arrest phenotype observed during progression of CML and in BCR-ABL+ ALL.

Description: Familial platelet disorder (FPD), a rare autosomal dominant disorder characterized by quantitative and qualitative platelet abnormalities, is considered as a model of genetic predisposition to acute myeloid leukemia (AML). So far, monoallelic RUNX1 germline mutations have been found in 19 of 20 families with reported FPD, and the analysis of blast cells from only 5 patients at acute leukemia (AL) stage has shown no additional RUNX1 abnormality. Here, we performed RUNX1 analysis at constitutional and somatic levels in 8 persons with FPD who developed AL from 4 independent families. In addition to the germline RUNX1 mutation, we identified a second RUNX1 alteration in 6 AML cases (acquired point mutations in 4 cases and duplication of the altered RUNX1 allele associated with acquired trisomy 21 in 2 other cases). Although haploinsufficiency of RUNX1 causes FPD, our findings suggest that a second genetic event involving RUNX1 is often associated with progression to AML.

Description: Abstract 3410 The ABL T315I mutation confers resistance to all approved tyrosine kinase inhibitors (TKIs) for the treatment of CML and Ph1+ ALL. The survival of patients harboring a T315I mutation, associated or not with other factors, is dependent on disease phase at the time of mutation detection. In vitro, in cell lines, this mutation alters kinase function and phosphorylation activity that increases oncogenicity (Skaggs et al., PNAS 2006). Using a matched-pair analysis, we aim to confirm whether or not these in vitro findings correlate into the clinic and provide higher rates of progression and poorer outcome specifically among CML patients remaining in chronic phase (CP) at T315I detection. A cohort of CP CML patients at T315I detection were identified from a database of an earlier epidemiologic study (Gr 1) was compared to a single-center, matched cohort of CML patients resistant to imatinib (IM), in CP, but not harboring the T315I mutation (Gr 2). All patients had had IM. These patients were matched on the 3 following variables: i) age at diagnosis, ii) time from diagnosis to IM initiation, iii) IM duration. The general characteristics of the 2 groups are displayed in table 1. Univariate analysis demonstrated that patients were equivalent for all factors except for the intervals from diagnosis to IM resistance and from diagnosis to TKI2 initiation that were significantly longer in Gr 1. Sixty-two percent of the patients in Gr 1 and 100% in Gr 2 took a TKI2. The duration of treatment with a 1st TKI2 was significantly longer in Gr 2, as a significant proportion of IM-resistant patients might respond to these agents. The cumulative incidence of switches for TKI2 was similar between the 2 groups (p=0.33). In a multivariate analysis the presence of the T315I mutation had a highly significant negative impact on overall survival (OS) from any time-point (HR since IM resistance=21.6, [5.4-87.3], p

Description: Abstract 3377 It is generally accepted that the BCR-ABL oncoprotein transformes haematopoietic stem cell and initiates chronic myeloid leukemia (CML). However, leukemogenesis is a complex process, and genomic heterogeneity of the chronic phase (CP) of the disease has been reported. At the molecular level, this intrinsic heterogeneity could support a causative link with the varying response to treatment and disease progression. Genetic analysis of candidate genes in myeloid malignancies reported mutations of the ten-eleven translocation 2 (TET2), the isocitrate deshydrogenase (IDH) 1 and IDH2, and the additional sex combs like 1 (ASXL1) genes in myeloproliferative, acute myeloid and myelodysplasic neoplasms. Similarly, we can stipulate that these candidate genes may contribute to phenotypic heterogeneity of CML. To investigate whether TET2, IDH1, IDH2 and ASXL1 defect could represent a significant event in CML, we selected 91 CML patients (pts) treated with imatinib (IM) at first line and presenting five profiles of IM response at time of the analysis: 1) 25 pts in major molecular response (MMR) at 12 months of IM; 2) 11 pts in CCR but presenting additional Philadelphia (Ph) negative clonal evolution; 3) 20 pts in partial cytogenetic response at 18 months of IM, referred as primary resistant (R1); 4) 20 pts in acute transformation 4 to 72 months after onset IM; and 5) 15 pts relapsing in CP of the disease, referred as secondary resistant (R2). The search for mutation was performed by sequencing the entire TET2 coding region (11 exons), the IDH1 and IDH2 exon 4 and the ASXL1 exon 12. Analysis of paired samples from CML diagnosis, time of IM response and, when available, CCR revealed: 1) 2 pts (2.2%) in acute transformation presenting 3 TET2 stop mutations not located within conserved region (del at A2079, substitution T4893A - both also been detected at diagnosis -, and del at C4851 which has not been detected at diagnosis, even by mutation-specific ASO-PCR); 2) no IDH1 and IDH2 mutation; and 3) 8 pts (8.7%) presenting ASXl1 stop mutations at diagnosis. Among them, 3 pts (two ins at G646 and one ins at V751) have reached MMR without detected mutations at this time; one R1 pt presenting ins at G646 had major cytogenetic response with 5% Ph+ cells but the mutation was not found at this time and the pt have progressed to MMR 9 months later; one pt with 23 bp del at R634 has evolved in acute transformation with detected mutation at this time; and 3 R2 pts presenting either 4 bp del at S895, del at R860 or 2 pb ins at A752 have lost CCR associated with lost of hematologic response in one case. In this later group of 3 pts, except for del at R860, all ASXL1 mutations were found in samples at time of relapse. We therefore conclude that, contrary to what has been reported in other myeloid malignancies, TET2, IDH1 and IDH2 are not commonly acquired in CML and may not represent a major genetic event in CML transformation. However, ASXL1 alteration seems to be an early event in CML leukemogenesis but does not seem to participate in the disease transformation. Disclosures: No relevant conflicts of interest to declare.

Description: Abstract 4171 NF1 acts as a tumor-suppressor gene by encoding neurofibromin1, a GTPase-activating protein (GAP) inhibiting Ras signaling pathway. Germline mutations or microdeletions of NF1 are responsible for neurofibromatosis type 1, and the somatic loss of the remained wild-type allele lead to malignant tumors or juvenile myelomonocytic leukemia (JMML). Furthermore, several studies revealed heterozygous somatic deletions of the 17q11.2 region including NF1 in adult myeloid malignancies. The reported frequencies of this abnormality varied between 2.6% and 11% in AML and this variation can be attributable to heterogeneity or size of the analysed cohorts. Previously, we analyzed 131 de novo AML cases (AML3 excluded) by Agilent™ 105K microarrays. 6/131 cases (4.6%) showed somatic deletions in 17q11.2, including a small minimal deleted region of 300 kb comprising the entire NF1 gene. To further investigate the incidence of NF1 deletion in de novo AML, 354 additional patients were therefore screened for the deletion by quantitative real-time PCR (Primers and TaqMan-based probe Hs 01778367_cn from Applied Biosystems), and FISH (NF1/MPO probe KBI-40144 from Kreatech) was performed to confirm the loss of NF1 copy number. Altogether, heterozygous NF1 deletion was observed in 17/485 (3.5%) de novo AML. Clinico-biological data were available from 14 NF1 deleted patients and 380 non-deleted patients included in the ALFA-9801 and 9802 French Trials. There were no significant differences between the 2 groups in age, sex ratio, leukocytosis, FAB classification of AML, mutational status of FLT3, NPM1, CEBPα and IDH. Interestingly, NF1 deletion was significantly correlated with unfavourable cytogenetic (50% vs 18%, p=0.008) and especially with monosomal karyotype (29% vs 9%, p=0.03). However, no statistical significant differences were observed for complete remission rate, relapse risk 3 years after diagnosis and 3-years overall survival. Screening for bi-allelic inactivation by sequencing the remained allele in NF1 deleted patients is in progress. We next evaluated NF1 gene expression for 93 patients of our cohort (3 with NF1 deletion and 90 without) by Affymetrix U133 Plus 2.0 microarrays. The 3 NF1 deleted patients revealed a significant reduced mean of NF1 expression level. Interestingly, about 10% of the NF1 non-deleted patients presented a similar decrease in NF1 expression rate. This suggests that mechanisms for transcriptional regulation (such as mutations or epigenetic silencing of NF1) may also contribute to AML pathogenesis. In conclusion, NF1 deletions occur in only 3.5% of de novo AML and are associated with unfavourable cytogenetic. This relatively low frequency of NF1 deletion can however be counterbalanced by others alterations acting at the transcriptional level and this remains to be investigated. Disclosures: No relevant conflicts of interest to declare.

Description: Introduction As clinical trials for relapsed Acute Myeloid Leukaemia (AML) patients do not accurately reflect the daily clinical reality, data regarding the outcome of these patients is scarce. We thus conducted a retrospective analysis to quantify the prospects of salvage treatment of primary refractory or first-relapse AML patients and to assess the contribution of allograft and intensive treatment regimens with respect to major risk groups in a real-life setting. Methods We performed a retrospective analysis of 163 patients diagnosed from 2005-2012, in 5 haematological centres in the north of France (Lille, Amiens, Roubaix, Valenciennes and Lens). We considered every patient in that time frame who was treated following an intensive pathway. Statistical analysis as performed using Kaplan-Meier survival analysis and logrank test in the SPSS software Results The mean age at diagnosis was 45 (range 16-70 years) and the median age at relapse was 48 (ranging 17-70 years). The median time from diagnosis to relapse was 8 months. 20.6% of patients were considered primary refractory (relapse within 60 days from diagnosis). The median overall survival was 28 months (95% CI was 17-38 months). There was no statistically significant survival difference between primary refractory patients and first relapsed patients. Unsurprisingly, survival was significantly (p

Description: Abstract 297 Background. Current models of cancer progression are based on evolution and clonal selection i.e. evolution of tumour cells inducing expansion of cells that acquire genetic lesions over time, related to ongoing mechanisms of genomic instability. An initiating event may be followed by gene mutation, copy number alteration (CNA) or copy neutral loss of heterozygosity (CN-LOH) that drive tumor progression and emergence of mechanisms of resistance to drugs. WM is a lymphoproliferative disorder characterized by bone marrow (BM) infiltration of lymphoplasmacytic cells that secrete monoclonal IgM antibody. The clinical course is characterized either by an indolent or smoldering status or a symptomatic profile that needs chemotherapy to control the progression of tumour cells. The majority of patients (pts)evolved from indolent to symptomatic, and the mechanisms of progression of WM are not fully understood to date. We hypothesized that we could gain insights into clonal evolution underlying disease progression of WM on a paired serial analysis of WM samples using genome wide SNPa, that allow both the detection of LOH and CNA. Method. BM samples of 19 untreated pts with WM (12 males, mean age: 67 years, 11 symptomatic pts) were analysed. All patients had Genome-Wide Human SNP Array 6.0 (Affymetrix chips) on at least two sequential tumor samples 〉 6 months apart (42 samples from 19 patients with two to three points). Tumoral DNA was extracted following CD19 B cells selection. Paired samples (tumor/normal T lymphocytes) were used as an intra-individual reference to identify germline polymorphisms. Size, position and location of genes were identified with UCSC Genome Browser HG18 assembly, LOH and CNA using genotyping console 3.02 software (Affymetrix). FISH analysis was performed to detect deletion 6q; 13q14, 11q22, TP53, trisomy 4 and 12 chromosomal aberrations using Vysis probes. P53 and MYD88 mutation were analyzed by sanger sequencing. Results. At initial sampling, SNPa detected a total of 76 CNA genetic aberrations (range 0 – 24 per genome) including 22 gains and 54 losses; 85% of patients had MYD88 L265P mutation. During the follow-up of all indolent WM that remained indolent, we haven't observed any new genetic aberrations, gain or loss (either CNA or CN-LOH) (n=8, mean follow-up: 63 months, range: 16–107 months). Among the 11 remaining patients (mean follow-up: 44.2 months, range: 7–92 months), a clonal evolution was observed in 6 cases. Three of them were symptomatic and acquired CNA or CN-LOH during clinical evolution: one case with acquisition of several CN-LOH, including one at 3p22 involving MYD88 locus associated to a mutation, one case with an additional deletion 7q31 which was observed in a patient with a chromothripsis at diagnosis, one case with emergence of subclonal del17p. The two remaining patients evolved from smoldering to symptomatic with a major variation in CNA number. Finally, loss of CNAs displayed at diagnosis was observed in one patient after chemotherapy and during indolent follow-up. In 5 cases, no detectable CNA changes were identified between the initial and subsequent sample at relapse. Conclusion. Our results using high resolution SNP array support the hypothesis that a symptomatic WM disease will favour genetic clonal evolution of tumor cells. In our study, 3 distinct genotypic patterns were observed: (i) absence of genomic variation in stable smoldering WM disease or in symptomatic relapsed patient. (ii) unstable genotype in symptomatic or asymptomatic patients switching to symptomatic suggesting high risk tumors that are less stable and more prone to change with time. (iii) loss of abnormalities suggesting that chemotherapy eradicated the dominant clone or that a genetically distinct relapsed clone has emerged. This study refines our understanding of the dynamic genetic changes in progressive WM. Further confirmation of the role of some candidate genes is underway. Disclosures: No relevant conflicts of interest to declare.

Description: In September 2003, the French CML study group (Fi-LMC) activated the four armed randomized SPIRIT trial comparing imatinib 400mg with imatinib 600mg, imatinib 400mg + ara-C and imatinib 400mg + pegylated interferon in newly diagnosed CML in chronic phase. The molecular monitoring was centralized and performed, according to the EAC protocol, in duplicate on the same BCR-ABL cDNA among two French laboratories (Bordeaux and Lille). Data were expressed as BCR-ABL/ABLx100 on the new internationally agreed scale (IS) using a conversion factor of 1.33 and 0.80 for Bordeaux and Lille respectively. A good correlation between the two laboratories was observed. During the first year of follow-up the quantification was performed each three months (M0 to M12). In May 2006, 297 of the 492 enrolled pts had a follow up of more than 12 months, and 263 pts were analysed at M12. Using the IS, the median values of the BCR-ABL/ABL normalized ratios were 90%, 6,4%, 0.68%, 0.32% and 0.16% at M0, M3, M6, M9, and M12 respectively. At M12, 15%, 29%, 27%, 17% and 12% of the pts presented a BCR-ABL/ABL ratio lower than 0.01%, 0.1% ,1%, 10%, and 100% respectively. Overall, 71% of the pts presented a ratio lower than 1%. Conventional cytogenetic data were available for 193 pts at M12: 156 pts (80%) were in complete cytogenetic response (CCR), 25 pts (13%) were in major cytogenetic response (MCR) and 12 pts (6.2%) were in minor or a lack of cytogenetic response. Among pts with a BCR-ABL transcript ratio lower than 1%, all except four were in CCR. The last 4 cases were in MCR associated with BCR-ABL ratios of: 0.96% for one pt, 0.08% and 0.12% for 2 pts (who further reached CCR at 6 and 18 months) and 0.128% for the last one. Percentages of Philadelphia positive metaphase (Ph+) were 4%, 6%, 5 % and 15% respectively. Among the 30 pts with a BCR-ABL ratio 〉 5%, none were in CCR and only 18 pts were in MCR. Among the 27 pts presenting a BCR-ABL ratio in the 1%–5% intervals, 20 pts were in CCR and 7 pts were in MCR (5 pts with Ph+ lower than 10% and two pts with 16% and 20% Ph+). In conclusion, our findings suggest that a ROC statistical test will be able to determine critical BCR-ABL/ABL ratios associated to CCR in our study. Nevertheless, at M12 the percentage of available data was superior using molecular than cytogenetic monitoring, suggesting that molecular monitoring expressed with the new international scale is probably sufficient fore more than 85 % of the pts treated by IM solely or in association.