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The prognostic value of IL7-receptor pathway (IL7Rp) mutations in T-cell acute lymphoblastic leukemia (T-ALL) remains unclear. We performed a comprehensive study of 200 adult patients with T-ALL included in the GRAALL2003/2005 protocols to address the clinical significance of IL7Rp mutations. Next-generation sequencing of the IL7Rp (IL7R/JAK1/JAK3/STAT5B) revealed that IL7Rp mutations were frequent in adult T-ALL (28%) particularly in immature/early T-cell progenitor (ETP)-ALL. They were associated with mutations of NOTCH-pathway, PHF6, and PRC2 components but not with K/NRAS. IL7Rp mutated (IL7Rp mut ) T-ALL were slow-responders, with a high rate of M2/M3 day-8 marrow compared with IL7Rp non-mutated (IL7Rp WT ) T-ALL (p = 0.002) and minimal residual disease positivity at 6-weeks (MRD1) (p = 0.008) but no difference in MRD2 positivity at 12-weeks. Despite this, no adverse prognosis was evidenced when censored for allogeneic hematopoietic stem cell transplantation (HSCT). In time-dependent analysis, HSCT did not benefit IL7Rp mut patients whereas it was of marked benefit to IL7Rp WT cases. IL7Rp-mutations identify a subgroup of slow-responder T-ALLs which benefit from post-induction chemotherapy regimens but not from HSCT. Our data suggest that prior knowledge of the mutation status of IL7Rp may influence HSCT decision and help to guide therapy reduction.

Minimal residual disease (MRD) quantification is widely used for therapeutic stratification in pediatric acute lymphoblastic leukemia (ALL). A robust, reproducible, sensitivity of at least 0.01% has been achieved for IG/TCR clonal rearrangements using allele-specific quantitative PCR (IG/TCR-QPCR) within the EuroMRD consortium. Whether multiparameter flow cytometry (MFC) can reach such inter-center performance in ALL MRD monitoring remains unclear. In a multicenter study, MRD was measured prospectively on 598 follow-up bone marrow samples from 102 high-risk children and 136 adult ALL patients, using IG/TCR-QPCR and 4/5 color MFC. At diagnosis, all 238 patients (100%) had at least one suitable MRD marker with 0.01% sensitivity, including 205/238 samples (86%) by using IG/TCR-QPCR and 223/238 samples (94%) by using MFC. QPCR and MFC were evaluable in 495/598 (83%) samples. Qualitative results (<0.01% or ≥0.01%) concurred in 96% of samples and overall positivity (including <0.01% and nonquantifiable positivity) was concurrent in 84%. MRD values ≥0.01% correlated highly (r(2)=0.87) and 69% clustered within half-a-log(10). QPCR and MFC can therefore be comparable if properly standardized, and are highly complementary. MFC strategies will benefit from a concerted approach, as does molecular MRD monitoring, and will contribute significantly to the achievement of 100% MRD informativity in adult and pediatric ALL.

Myeloproliferative neoplasms are frequently associated with aberrant constitutive tyrosine kinase (TK) activity resulting from chimaeric fusion genes or point mutations such as BCR-ABL1 or JAK2 V617F. We report here the cloning and functional characterization of two novel fusion genes BCR-RET and FGFR1OP-RET in chronic myelomonocytic leukemia (CMML) cases generated by two balanced translocations t(10;22)(q11;q11) and t(6;10)(q27;q11), respectively. The two RET fusion genes leading to the aberrant activation of RET, are able to transform hematopoietic cells and skew the hematopoietic differentiation program towards the monocytic/macrophage lineage. The RET fusion genes seem to constitutively mimic the same signaling pathway as RAS mutations frequently involved in CMML. One patient was treated with Sorafenib, a specific inhibitor of the RET TK function, and demonstrated cytological and clinical remissions.

Imatinib mesylate is the sole BCR-ABL tyrosine kinase inhibitor approved as first-line treatment of accelerated-phase (AP) chronic myeloid leukemia (CML). Indication was based on the STI571 0109 study, in which imatinib favorably compared to historical treatments in patients failing prior therapies. The relevance of these results to currently newly diagnosed AP-CML patients remains unknown. We evaluated the benefit of imatinib in 42 newly diagnosed AP-CML patients. In all, 16 patients had hematological acceleration without chromosomal abnormalities in addition to the Philadelphia chromosome (ACAs; HEM-AP), 16 solely had ACAs (ACA-AP) and 10 had hematological acceleration plus ACAs (HEM-AP + ACA). Major cytogenetic responses were achieved in 93.7% of HEM-AP patients, 75% of patients with ACA-AP (P=NS) and 40% of patients with HEM-AP + ACA (P=0.0053). The 24-month failure-free survival rate was 87.5% in HEM-AP patients, 43.8% in ACA-AP patients and 15% in HEM-AP + ACA patients (P=0.022). The 24-month estimate of progression-free survival was 100% in HEM-AP patients, 92.8% in ACA-AP patients and 58.3% in HEM-AP + ACA patients (P=0.0052). In conclusion, frontline imatinib allows favorable outcomes in HEM-AP and ACA-AP patients but appears insufficient for patients with HEM-AP + ACA. Broader-target and/or more potent BCR-ABL tyrosine kinase inhibitors alone or in combination may be considered in this setting.

Adult and child B-cell progenitor acute lymphoblastic leukemia (BCP-ALL) differ in terms of incidence and prognosis. These disparities are mainly due to the molecular abnormalities associated with these two clinical entities. A genome-wide analysis using oligo SNP arrays recently demonstrated that PAX5 (paired-box domain 5) is the main target of somatic mutations in childhood BCP-ALL being altered in 38.9% of the cases. We report here the most extensive analysis of alterations of PAX5 coding sequence in 117 adult BCP-ALL patients in the unique clinical protocol GRAALL-2003/GRAAPH-2003. Our study demonstrates that PAX5 is mutated in 34% of adult BCP-ALL, mutations being partial or complete deletion, partial or complete amplification, point mutation or fusion gene. PAX5 alterations are heterogeneous consisting in complete loss in 17%, focal deletions in 10%, point mutations in 7% and translocations in 1% of the cases. PAX5 complete loss and PAX5 point mutations differ. PAX5 complete loss seems to be a secondary event and is significantly associated with BCR-ABL1 or TCF3-PBX1 fusion genes and a lower white blood cell count.

Fifty-four percent of adults with acute lymphoblastic leukemia (ALL) who entered the LALA-94 trial experienced a first relapse. We examined the outcome of these 421 adult patients. One hundred and eighty-seven patients (44%) achieved a second complete remission (CR). The median disease-free survival (DFS) was 5.2 months with a 5-year DFS at 12%. Factors predicting a better outcome after relapse were any transplant performed in second CR (P<0.0001), a first CR duration >1 year (P=0.04) and platelet level >100 x 10(9)/l at relapse (P=0.04). Risk groups defined at diagnosis and treatment received in first CR did not influence the outcome after relapse. The best results were obtained in a subset of patients who were eligible for allogeneic stem cell transplantation (SCT). Geno-identical allogeneic SCT was performed in 55 patients, and 3 patients received donor lymphocyte infusions. Forty-four transplantations were performed from an unrelated donor (of which four were cord blood). We conclude that most adult patients with recurring ALL could not be rescued using current available therapies, although allogeneic SCT remains the best therapeutic option.

Adult patients with acute lymphoblastic leukemia (ALL) and t(1;19)/E2A-PBX1 or t(4;11)/MLL-AF4 have a poor outcome. We have evaluated the impact of an intensified post-remission therapy using a high-dose chemotherapy course followed by allogeneic or autologous SCT on the outcome of 58 patients with t(1;19)/E2A-PBX1 (E2A group, n=24) or t(4;11)/MLL-AF4 (MLL group, n=34) treated in the LALA-94 multicenter prospective study. Patients in the MLL group had higher WBC counts and more frequent DIC. CR rates achieved by MLL and E2A groups were similar to other B-cell ALL (87, 82 and 86% respectively). While in CR, patients with a donor were assigned to alloSCT (n=22), the remaining patients with were randomized between autoSCT (n=15) or chemotherapy (n=8). Five-year overall survival was 31 and 45% for E2A and MLL groups, respectively. In both groups, DFS was higher in the alloSCT arm as compared to autoSCT and chemotherapy arms. The results of this study show that chemotherapy intensification did not overcome the poor prognosis of adults with t(1;19)/E2A-PBX1. Allogeneic SCT should thus be offered in first CR to patients with t(1;19)/E2A-PBX1 or t(4;11)/MLL-AF4. New therapeutic approaches are needed for patients without donor.

Imatinib combined with high-dose chemotherapy is now becoming the gold standard for treatment of Philadelphia chromosome-positive acute leukemias. However, in all studies imatinib dosage was tapered to 400-600 mg per day. We decided to initiate a clinical trial to evaluate an opposite strategy based on high-dose imatinib (800 mg per day) combined with a less intensive chemotherapeutic regimen (vincristine and dexamethasone), which we called the DIV induction regimen. Thirty-one patients (18 relapsing or refractory Ph+ acute lymphoblastic leukemias and 13 lymphoid blast crisis chronic myelogenous leukemias) were enrolled. Complete remission (CR) was obtained in 28 out of 30 assessable patients. The median bcr-abl/abl ratio after the induction course was 0.1%. Median time to neutrophil recovery was 21 days. Fungus infections were observed in six patients out of 31 and possibly related to dexamethasone. Neuropathy due to vincristine was noted in 14 cases. Nine out of 19 patients under 55 years received allogenic stem cell transplantation after a median time of 78 days post-CR. Patients older than 55 years experienced a 90% CR rate without additional toxicities, suggesting the DIV regimen may also be proposed as a front line therapy in older patients.

Chromosomal translocations with breakpoints in T-cell receptor (TCR) genes are recurrent in T-cell malignancies. These translocations involve the TCRalphadelta gene (14q11), the TCRbeta gene (7q34) and to a lesser extent the TCRgamma gene at chromosomal band 7p14 and juxtapose T-cell oncogenes next to TCR regulatory sequences leading to deregulated expression of those oncogenes. Here, we describe a new recurrent chromosomal inversion of chromosome 7, inv(7)(p15q34), in a subset of patients with T-cell acute lymphoblastic leukemia characterized by CD2 negative and CD4 positive, CD8 negative blasts. This rearrangement juxtaposes the distal part of the HOXA gene cluster on 7p15 to the TCRbeta locus on 7q34. Real time quantitative PCR analysis for all HOXA genes revealed high levels of HOXA10 and HOXA11 expression in all inv(7) positive cases. This is the first report of a recurrent chromosome rearrangement targeting the HOXA gene cluster in T-cell malignancies resulting in deregulated HOXA gene expression (particularly HOXA10 and HOXA11) and is in keeping with a previous report suggesting HOXA deregulation in MLL-rearranged T- and B cell lymphoblastic leukemia as the key factor in leukaemic transformation. Finally, our observation also supports the previous suggested role of HOXA10 and HOXA11 in normal thymocyte development.

The purpose of this study was to assess the safety and efficacy of stem cell transplantation (SCT) mainly autologous SCT as consolidation therapy in APL patients who relapsed and achieved a second complete remission (CR2). Fifty adult patients with a first relapsed APL, of whom 39 had been previously treated with ATRA, entered a multicenter trial of oral ATRA until complete remission (CR) achievement followed by timed sequential chemotherapy (EMA combining etoposide 200 mg/m2/day for 3 days, mitoxantrone 12 mg/m2/day for 3 days, and cytarabine 500 mg/m2/day for two sequences of 3 days). EMA was started either after CR achievement, or on day 1 of ATRA because of initial white blood cell (WBC) counts >5 x 10(9)/l, or rapidly added to ATRA in order to prevent ATRA syndrome because WBC count increased under ATRA. Forty-five patients (90%, 95% CI 78%-97%) were in CR after induction therapy. Five patients died from infection during aplasia following EMA chemotherapy. Eleven patients who achieved CR had a familial HLA-identical donor and were allografted. The median disease-free survival (DFS) of allografted patients was 8.2 months. The 34 other CR patients were scheduled for autologous peripheral blood (PB) SCT (intent-to-treat group). Actually, autologous transplantation was only carried out in 22 patients (65%) (17 PBSCT and five autologous bone marrow transplantation (BMT)). Reasons for not autografting were early relapse (three patients), severe toxicity of EMA chemotherapy (six patients), and refusal or failure of stem cell harvest (three patients). The 3-year DFS rate of patients actually autografted was 77%. Among the 17 autografted patients still in CR2, nine patients have already reached a longer CR2 than first CR (CR1). Results of detection of PML/RARalpha by RT-PCR after autologous transplantation show negative findings in eight of the nine patients tested. We conclude that (1) ATRA combined to EMA chemotherapy is effective in the treatment of relapsed APL; (2) allogeneic BMT may be too toxic after salvage treatment including EMA intensive chemotherapy; (3) clinical outcome of autografted patients and preliminary molecular results regarding detection of PML/RARalpha after autologous PBSCT are encouraging.

In 204 adult patients with de novo acute myeloid leukemia (AML), we prospectively compared allogeneic bone marrow transplantation (alloBMT), autologous stem cell transplantation (ASCT) and chemotherapy (Chemo). 162 patients (79.4%) achieved a complete remission (CR). Of the 135 patients who were still in CR after consolidation, 96 patients were less than 46 years of age: 36 patients had an HLA-identical sibling donor and were allocated for alloBMT (group I); they were compared to the 60 other patients who did not have an HLA-identical sibling donor and were treated with either ASCT or chemotherapy (group II). The 3-year disease-free survival was higher for group I patients (66.5 +/- 16%) than for the 60 group II patients (42.4 +/- 13%) (P < 0.05). The actuarial risk of relapse at 3 years was significantly lower for group I patients (24 +/- 15%) than for the other 60 group II patients (56 +/- 13%; P < 0.009). By multivariate analysis, the disease-free survival and risk of relapse were influenced by the initial WBC count (P < 0.02 and P < 0.006), the number of chemotherapy courses for CR (P < 0.001 and P < 0.01) and the type of post-induction treatment (alloBMT vs no alloBMT; P < 0.1 and P < 0.02). The 99 patients who did not fulfill the inclusion criteria for alloBMT were given intensive chemotherapy including high-dose aracytine. When they were still in CR (n = 77), these patients were then randomized for either ASCT (n = 39) or Chemo (n = 38). We were unable to detect any statistical difference between ASCT and Chemo for either disease-free survival, risk of relapse or survival. These results indicate that alloBMT seems to produce results which are at least superior to those of other therapeutic modalities. The results of either ASCT or Chemo look similar.

A prospective randomized study was conducted comparing the efficacy and toxicity of two anthracyclines for the treatment of patients with acute myeloid leukemia (AML) between 55 and 75 years. A total of 220 patients were randomized to receive as induction chemotherapy cytosine arabinoside (Ara-C: 100 mg/m2/day; continuous infusion for 7 days) combined with either daunorubicin (DNR: 50 mg/m2/day, i.v. bolus for 3 days) (n=108) or idarubicin (IDA: 8 mg/m2/day, i.v. bolus for 5 days) (n=112). The complete remission (CR) rate was similar (P=0.296) after IDA (76/112; 68%) and DNR (66/108; 61%) (P=0.3). For patients aged 55-65, the CR rate was significantly higher after IDA (39/47; 83%) than after DNR (29/50; 58%) (P=0.007). Persistent leukemia was more frequent after DNR (26/108) than after IDA (13/112; P=0.015). Hematological and extra-hematological toxicities were similar. The CR patients were given a consolidation course of chemotherapy with Ara-C: 50 mg/m2/12 h, subcutaneously for 5 days, combined with either DNR:30 mg m2/day, i.v. bolus for 3 days or IDA:8 mg/m2/day i.v. bolus for 3 days according to the initial randomization, and then received a continuous maintenance treatment for 2 years. The survival and disease-free survival (DFS) were similar in both groups; there was no difference in the risk of relapse. However, there was a trend for a longer event-free survival (EFS) in the IDA group than for the DNR patients (P=0.07). Our results seem to indicate that IDA is probably more efficient than DNR for AML patients between 55 and 75 years, and confirm the data published in other studies comparing prospectively IDA and DNR in adults.

A group of 201 adult patients, 127 younger and 74 older than 55 years, with de novo acute myeloid leukemia were investigated to determine the prognostic significance of karyotype on early death (toxic or aplastic death occurring before hematopoietic recovery), drug resistance, continuous complete remission (CCR) and survival probabilities at 5 years. A good prognostic impact was found for t(8;21), t(15;17) and inv(16). The best factor proved to be t(8;21) (5-year survival probability: 50%), followed by t(15;17) (5-year survival probability: 39%) and by inv(16) (5-year survival probability: 43%). An intermediate outcome was found in patients with trisomy 8 (27% alive at 5 years) and in patients with numerical abnormalities other than -7 and +8 (33% in CCR and 62% alive at 5 years). Normal karyotypes had a different prognostic impact according to age: intermediate in young and good in older patients. A poor outcome was observed among patients with del(5q)/-5 (median survival: 1 month), with 11q23 rearrangements (median survival: 1.5 months) and with del(7q)/-7 (median survival: 10 months). The 'other structural change' group was also found to be a poor risk population (5-year survival probability: 5%) whereas complex karyotypes were predictive of short survivals only in older patients. Conversely, del(7q)/-7 and +8 as secondary changes, had no prognostic impact.