Bone marrow tryptase as a possible diagnostic criterion for adult systemic mastocytosis.

BACKGROUND: Mastocytosis is difficult to diagnose, especially when systemic mast cell activation symptoms are not present or involve only one extracutaneous organ. OBJECTIVE: The main objective was to evaluate the accuracy of the bone marrow tryptase level in the diagnosis of systemic mastocytosis in patients with a clinical suspicion of mastocytosis. METHODS: We included all adult patients evaluated in our centre between December 2009 and 2013 for suspected mastocytosis as part of a standardized procedure and who had a bone marrow and serum tryptase assay on the same day. The diagnosis of systemic mastocytosis was established on the basis of the World Health Organization criteria as the gold standard. The accuracy of the bone marrow tryptase level in the diagnosis of systemic mastocytosis was assessed by a receiver operating characteristics curve analysis. The different sensitivity and specificity values, corresponding to the set of possible bone marrow tryptase level cut-off values, were estimated with 95% confidence intervals. RESULTS: Seventy-three patients were included. The diagnosis of systemic mastocytosis was established in 43 patients (58.9%). The median bone marrow tryptase level was 423 µg/L [95% CI: 217-868] in the systemic mastocytosis group and 7.5 µg/L [95% CI: 4.6-17.1] in the non-systemic mastocytosis group (P < 0.001). A cut-off value of 50 µg/L for bone marrow tryptase identified systemic mastocytosis with a sensitivity of 93.0% [95% CI: 80.9-98.5%] and a specificity of 90.0% [95% CI: 73.5-97.9%]. CONCLUSION AND CLINICAL RELEVANCE: The bone marrow tryptase level appears to be a valuable diagnostic criterion for confirming systemic mastocytosis. If this diagnosis can reliably be excluded by evaluation of the bone marrow tryptase level, there would be no need to perform a bone marrow biopsy.

The care center influences the management of lymphoma patients in a universal health care system: an observational cohort study.

BACKGROUND: Healthcare providers-related disparities in adherence to the treatment plan among lymphoma patients are found even in a universal healthcare system, but the mechanism remains unclear. We investigated the association between the type of care center and the relative dose intensity and determined whether it persists after adjustment for patients' recruitment differences. METHODS: Prospective observational cohort study of 294 patients treated with standard protocols for diffuse large B-cell lymphoma (DLBCL) in teaching or community public hospitals or in private centers in the French Midi-Pyrénées region from 2006-2013. To test our assumptions, we used multinomial and mixed-effect logistic models progressively adjusted for patients' biomedical characteristics, socio-spatial characteristics and treatment-related toxicity events. RESULTS: Patients treated using standard protocols in the teaching hospital had more advanced stage and poorer initial prognosis without limitation regarding the distance from the residence to the care center. Patients' recruitment profile across the different types of care center failed to explain the difference in relative dose intensity. Low relative dose intensity was less often observed in teaching hospital than elsewhere. CONCLUSION: We showed that even in a universal healthcare system, disparities in the management of DLBCL patients' do exist according to the types of care center. A main issue may be to find and diffuse the reasons of this benefit in cancer management in the teaching hospital to the other centers.

Phase III study of ACVBP versus ACVBP plus rituximab for patients with localized low-risk diffuse large B-cell lymphoma (LNH03-1B).

BACKGROUND: The superiority of a chemotherapy with doxorubicin, cyclophosphamide, vindesine, bleomycin and prednisone (ACVBP) in comparison with cyclophosphamide, doxorubicin, vincristin and prednisone plus radiotherapy for young patients with localized diffuse large B-cell lymphoma (DLBCL) was previously demonstrated. We report the results of a trial which evaluates the role of rituximab combined with ACVBP (R-ACVBP) in these patients. PATIENTS AND METHODS: Untreated patients younger than 66 years with stage I or II DLBCL and no adverse prognostic factors of the age-adjusted International Prognostic Index were randomly assigned to receive three cycles of ACVBP plus sequential consolidation with or without the addition of four infusions of rituximab. RESULTS: A total of 223 patients were randomly allocated to the study, 110 in the R-ACVBP group and 113 in the ACVBP group. After a median follow-up of 43 months, our 3-year estimate of event-free survival was 93% in the R-ACVBP group and 82% in the ACVBP group (P = 0.0487). Three-year estimate of progression-free survival was increased in the R-ACVBP group (95% versus 83%, P = 0.0205). Overall survival did not differ between the two groups with a 3-year estimates of 98% and 97%, respectively (P = 0.686). CONCLUSION: In young patients with low-risk localized DLBCL, rituximab combined with three cycles of ACVBP plus consolidation is significantly superior to ACVBP plus consolidation alone.

A 4-weekly course of rituximab is safe and improves tumor control for patients with minimal residual disease persisting 3 months after autologous hematopoietic stem-cell transplantation: results of a prospective multicenter phase II study in patients with follicular lymphoma.

BACKGROUND: This study explored the efficacy and safety of rituximab as treatment of clinical or molecular residual disease after autologous stem-cell transplantation (ASCT) in follicular lymphoma (FL). PATIENTS AND METHODS: Forty patients with CD20+ FL and clinically (group A, n = 14) or clono-specific PCR-detectable (group B, n = 25) residual disease persisting 3 months after ASCT received rituximab 375 mg/m² once weekly for 4 weeks. RESULTS: Response rate at day 50 was 36% [90% confidence interval (CI) 15-61] in group A (World Health Organization criteria) and 52% (90% CI 34-70) in group B (conversion PCR-undetectable status to undetectable status). The best response rate was 71% [nine complete responses (CRs) and one partial response] in group A and 76% in group B. At 36 months, all 10 responses persisted in group A, whereas 46% of patients in group B still had PCR-undetectable disease. Furthermore, 68% of patients in group B were still in clinical CR. Rituximab after ASCT was safe with few grade 3-4 toxic effects (15% patients), mainly acute reactions and infections. CONCLUSION: Rituximab induced a high rate of durable CRs in patients with clinically detectable disease, as well as durable eradication of PCR-detectable disease in patients with FL after ASCT. Continued molecular responses assessed with a highly sensitive and clono-specific PCR technique were correlated with an excellent disease control.

Rituximab versus observation after high-dose consolidative first-line chemotherapy with autologous stem-cell transplantation in patients with poor-risk diffuse large B-cell lymphoma.

BACKGROUND: This study compared the induction regimens doxorubicin, cyclophosphamide and etoposide (ACE) with doxorubicin, cyclophosphamide, vincristine, bleomycin and prednisone (ACVBP) before high-dose therapy (HDT) followed by autologous stem-cell transplantation (ASCT) for patients with poor-risk diffuse large B-cell lymphoma (DLBCL). A second randomisation compared rituximab with observation post-ASCT. MATERIALS AND METHODS: Four hundred and seventy-six patients <60 years old with newly diagnosed CD20+ DLBCL were randomised to induction with ACE or ACVBP. Three hundred and thirty responders received HDT followed by ASCT. After ASCT, 269 patients were re-randomised to receive either maintenance rituximab or observation alone. Randomisation was stratified by the quality of response to ASCT. The primary end point of this study was event-free survival (EFS). RESULTS: At a median of 4 years' follow-up from the second randomisation, there was a trend (P = 0.1) towards increased EFS for patients who received rituximab compared with observation. CONCLUSION: The type of induction therapy (ACVBP or ACE) did not significantly affect overall survival at a median 51 months' follow-up.

RSK2 is a new Pim2 target with pro-survival functions in FLT3-ITD-positive acute myeloid leukemia.

Acute myeloid leukemia (AML) with the FLT3 internal tandem duplication (FLT3-ITD AML) accounts for 20-30% of AML cases. This subtype usually responds poorly to conventional therapies, and might become resistant to FLT3 tyrosine kinase inhibitors (TKIs) due to molecular bypass mechanisms. New therapeutic strategies focusing on resistance mechanisms are therefore urgently needed. Pim kinases are FLT3-ITD oncogenic targets that have been implicated in FLT3 TKI resistance. However, their precise biological function downstream of FLT3-ITD requires further investigation. We performed high-throughput transcriptomic and proteomic analyses in Pim2-depleted FLT3-ITD AML cells and found that Pim2 predominantly controlled apoptosis through Bax expression and mitochondria disruption. We identified ribosomal protein S6 kinase A3 (RSK2), a 90 kDa serine/threonine kinase involved in the mitogen-activated protein kinase cascade encoded by the RPS6KA3 gene, as a novel Pim2 target. Ectopic expression of an RPS6KA3 allele rescued the viability of Pim2-depleted cells, supporting the involvement of RSK2 in AML cell survival downstream of Pim2. Finally, we showed that RPS6KA3 knockdown reduced the propagation of human AML cells in vivo in mice. Our results point to RSK2 as a novel Pim2 target with translational therapeutic potential in FLT3-ITD AML.

High-dose imatinib mesylate combined with vincristine and dexamethasone (DIV regimen) as induction therapy in patients with resistant Philadelphia-positive acute lymphoblastic leukemia and lymphoid blast crisis of chronic myeloid leukemia.

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.

Extramedullary relapse in acute promyelocytic leukemia treated with all-trans retinoic acid and chemotherapy.

We analyzed the incidence, presenting features, risk factors of extramedullary (EM) relapse occurring in acute promyelocytic leukemia (APL) treated with all-trans retinoic acid (ATRA) and chemotherapy by using a competing-risk method. In total, 740/ 806 (92%) patients included in three multicenter trials (APL91, APL93 trials and PETHEMA 96) achieved CR, of whom 169 (23%) relapsed, including 10 EM relapses. Nine relapses involved the central nervous system (CNS) and one the skin, of which two were isolated EM relapse. In patients with EM disease, median WBC count was 26950/mm3 (7700-162000). The 3-year cumulative incidence of EM disease at first relapse was 5.0%. Univariate analysis identified age <45 years (P=0.05), bcr3 PML-RARalpha isoform (P= 0.0003) and high WBC counts (> or = 10,000/ mm3) (P<0.0001) as risk factors for EM relapse. In multivariate analysis, only high WBC count remained significant (P= 0.001). Patients with EM relapse had a poorer outcome since median survival from EM relapse was 6.7 months as compared to 26.3 months for isolated BM relapse (P=0.04). In conclusion, EM relapse in APL occurs more frequently in patients with increased WBC counts (> or = 10,000/mm3) and carries a poor prognosis. Whether CNS prophylaxis should be systematically performed in patients with WBC > or = 10,000/mm3 at diagnosis remains to be established.

High mTORC1 activity drives glycolysis addiction and sensitivity to G6PD inhibition in acute myeloid leukemia cells.

Alterations in metabolic activities are cancer hallmarks that offer a wide range of new therapeutic opportunities. Here we decipher the interplay between mTORC1 activity and glucose metabolism in acute myeloid leukemia (AML). We show that mTORC1 signaling that is constantly overactivated in AML cells promotes glycolysis and leads to glucose addiction. The level of mTORC1 activity determines the sensitivity of AML cells to glycolysis inhibition as switch-off mTORC1 activity leads to glucose-independent cell survival that is sustained by an increase in mitochondrial oxidative phosphorylation. Metabolic analysis identified the pentose phosphate pathway (PPP) as an important pro-survival pathway for glucose metabolism in AML cells with high mTORC1 activity and provided a clear rational for targeting glucose-6-phosphate dehydrogenase (G6PD) in AML. Indeed, our analysis of the cancer genome atlas AML database pinpointed G6PD as a new biomarker in AML, as its overexpression correlated with an adverse prognosis in this cohort. Targeting the PPP using the G6PD inhibitor 6-aminonicotinamide induces in vitro and in vivo cytotoxicity against AML cells and synergistically sensitizes leukemic cells to chemotherapy. Our results demonstrate that high mTORC1 activity creates a specific vulnerability to G6PD inhibition that may work as a new AML therapy.

Prognostic factors in patients with aggressive non-Hodgkin's lymphoma treated by front-line autotransplantation after complete remission: a cohort study by the Groupe d'Etude des Lymphomes de l'Adulte.

PURPOSE: Improved survival has been observed in aggressive non-Hodgkin's lymphoma (NHL) patients with adverse prognostic factors when autotransplantation (ASCT) was performed after complete remission. However, there is no agreement on the prognostic factors for patients treated with ASCT. We aimed to estimate the prognostic effect of clinical and biologic variables on relapse and survival rates by pooling the data from two trials. PATIENTS AND METHODS: Of the patients treated in the LNH87 and LNH93 trials, 330 under age 60 years achieved complete remission after high-dose cyclophosphamide, doxorubicin, vincristine, and prednisone, and received consolidative ASCT; 16% of patients had T-cell NHL. The International Prognostic Index (IPI) score was 0 for 11%, 1 for 23%, 2 for 51%, and 3 for 15%. Univariate and Cox multivariate survival analyses were retrospectively performed on this population. RESULTS: Overall survival was 75 +/- 5% at 5 years and disease-free survival (DFS) 67 +/- 5%. For T-cell NHL, these scores were 54% and 44%, respectively. The IPI score had no prognostic value and only the following parameters adversely affected overall survival and DFS (P <.05): marrow involvement; more than one extranodal site; histology (nonanaplastic T-cell v others); and type of anthracycline (mitoxantrone v doxorubicin, for DFS only). CONCLUSION: These results suggest that ASCT can prevent relapse in patients with adverse IPI factors. However, patients presenting with a nonanaplastic T-cell phenotype, more than one extranodal site, or marrow involvement still have a higher risk of relapse. These factors should be taken into account when designing post-ASCT maintenance studies.

Report of 34 patients with clonal chromosomal abnormalities in Philadelphia-negative cells during imatinib treatment of Philadelphia-positive chronic myeloid leukemia.

Imatinib mesylate (Gleevec), an inhibitor of the BCR-ABL tyrosine kinase, was introduced recently into the therapy of chronic myeloid leukemia (CML). Several cases of emergence of clonal chromosomal abnormalities after therapy with imatinib have been reported, but their incidence, etiology and prognosis remain to be clarified. We report here a large series of 34 CML patients treated with imatinib who developed Philadelphia (Ph)-negative clones. Among 1001 patients with Ph-positive CML treated with imatinib, 34 (3.4%) developed clonal chromosomal abnormalities in Ph-negative cells. Three patients were treated with imatinib up-front. The most common cytogenetic abnormalities were trisomy 8 and monosomy 7 in twelve and seven patients, respectively. In 15 patients, fluorescent in situ hybridization with specific probes was performed in materials archived before the initiation of imatinib. The Ph-negative clone was related to previous therapy in three patients, and represented a minor pre-existing clone that expanded after the eradication of Ph-positive cells with imatinib in two others. However, in 11 patients, the new clonal chromosomal abnormalities were not detected and imatinib may have had a direct effect. No myelodysplasia was found in our cohort. With a median follow-up of 24 months, one patient showed CML acceleration and two relapsed.

A robust and rapid xenograft model to assess efficacy of chemotherapeutic agents for human acute myeloid leukemia.

Relevant preclinical mouse models are crucial to screen new therapeutic agents for acute myeloid leukemia (AML). Current in vivo models based on the use of patient samples are not easy to establish and manipulate in the laboratory. Our objective was to develop robust xenograft models of human AML using well-characterized cell lines as a more accessible and faster alternative to those incorporating the use of patient-derived AML cells. Five widely used AML cell lines representing various AML subtypes were transplanted and expanded into highly immunodeficient non-obese diabetic/LtSz-severe combined immunodeficiency IL2Rγc(null) mice (for example, cell line-derived xenografts). We show here that bone marrow sublethal conditioning with busulfan or irradiation has equal efficiency for the xenotransplantation of AML cell lines. Although higher number of injected AML cells did not change tumor engraftment in bone marrow and spleen, it significantly reduced the overall survival in mice for all tested AML cell lines. On the basis of AML cell characteristics, these models also exhibited a broad range of overall mouse survival, engraftment, tissue infiltration and aggressiveness. Thus, we have established a robust, rapid and straightforward in vivo model based on engraftment behavior of AML cell lines, all vital prerequisites for testing new therapeutic agents in preclinical studies.

Azacitidine frontline therapy for unfit acute myeloid leukemia patients: clinical use and outcome prediction.

Hypomethylating agents are able to prolong the overall survival of some patients diagnosed with acute myeloid leukemia. The aim of this study was to evaluate the clinical use of azacitidine as front-line therapy in unfit acute myeloid leukemia (AML) patients and to develop a clinical prediction model to identify which patients may benefit more from the drug. One hundred and ten untreated unfit AML patients received front-line azacitidine therapy in Spain, and response and survival were evaluated in them following European LeukemiaNet (ELN) guidelines. A clinical prediction rule was obtained from this population that was validated and refined in 261 patients treated in France, Austria and Italy. ELN response was achieved in 21.0% of the 371 patients (CI95% 17.0-25.5) and did not depend on bone marrow blast cell percentage. Median overall survival was 9.6 months (CI95% 8.5-10.8) and 40.6% of the patients were alive at 1 year (CI95% 35.5-45.7). European ALMA score (E-ALMA), based on performance status, white blood cell counts at azacitidine onset and cytogenetics, discriminated three risk groups with different survival and response rates. Azacitidine seems a reasonable therapeutic option for most unfit AML patients, i.e. those displaying a favorable or intermediate E-ALMA score.

Therapy-related acute myeloblastic leukemia after mitoxantrone treatment in a patient with MS.

The authors report a patient with severe secondary progressive MS who responded to mitoxantrone but developed a fatal acute myeloblastic leukemia 15 months after completion of mitoxantrone therapy. Therapy-related acute leukemia (TRAL) in relation with mitoxantrone is rare; this patient was the first case among a cohort of 802 French MS patients treated with mitoxantrone. Nevertheless, this case stresses the need to further evaluate the long-term risk of TRAL in patients with MS who receive mitoxantrone.

Changing use of intensive care for hematological patients: the example of multiple myeloma.

OBJECTIVE: Intensivists generally view patients with hematological malignancies as poor candidates for intensive care. Nevertheless, hematologists have recently developed more aggressive treatment protocols capable of achieving prolonged complete remissions in many of these patients. This change mandates a reappraisal of indications for ICU admission in each type of hematological disease. Improved knowledge of the prognosis is of assistance in making treatment decisions. PATIENTS AND METHODS: The records of 75 myeloma patients consecutively admitted to our ICU between 1992 and 1998 were reviewed retrospectively and predictors of 30-day mortality were identified using stepwise logistic regression. RESULTS: The median age was 56 years (37-84). Chronic health status (Knaus scale) was C or D in 39 cases. Fifty-five patients (73%) had stage III disease and 17 had a complete or partial remission. Autologous bone marrow transplantation had been performed in 28 patients (37%). ICU admission occurred between 1992 and 1995 in 41 patients (54.7%), and between 1996 and 1998 in 34 patients (45.3%). The median SAPS II and LOD scores were 60 (23-107) and 7 (0-21), respectively. Reasons for ICU admission were acute respiratory failure in 39 patients (52%) and shock in 31 (41%). Forty-six patients (61%) required mechanical ventilation. Fifty patients (66%) received vasopressors and 24 dialysis. Thirty-day mortality was 57%. Only five parameters were independently associated with 30-day mortality in the multivariate model: female gender (OR = 5.12), mechanical ventilation (OR = 16.7) and use of vasopressor agents (OR = 5.67) were associated with a higher mortality rate, whereas disease remission (OR = 0.16) and ICU admission between 1996 and 1998 (OR = 0.09) were associated with a lower one. CONCLUSION: The prognosis for myeloma patients in the ICU is improving over time. This may reflect either recent therapeutic changes in hematological departments and ICUs or changes in patient selection for ICU admission. Hematologists and intensivists should work closely together to select hematological patients likely to benefit from ICU admission.

Pim kinases phosphorylate Chk1 and regulate its functions in acute myeloid leukemia.

Phosphorylation by Akt on Ser 280 was reported to induce cytoplasmic retention and inactivation of CHK1 with consequent genetic instability in PTEN-/- cells. In acute myeloid leukemia cells carrying the FLT3-internal tandem duplication (ITD) mutation, we observed high rates of FLT3-ITD-dependent CHK1 Ser 280 phosphorylation. Pharmacological inhibition and RNA interference identified Pim1/2, not Akt, as effectors of this phosphorylation. Pim1 catalyzed Ser 280 phosphorylation in vitro and ectopic expression of Pim1/2-induced CHK1 phosphorylation. Ser 280 phosphorylation did not modify CHK1 localization, but facilitated its cell cycle and resistance functions in leukemic cells. FLT3, PIM or CHK1 inhibitors synergized with DNA-damaging agents to induce apoptosis, allowing cells to bypass the etoposide-induced G2/M arrest. Consistently, etoposide-induced CHK1-dependent phosphorylations of CDC25C on Ser 216 and histone H3 on Thr11 were decreased upon FLT3 inhibition. Accordingly, ectopic expression of CHK1 improved the resistance of FLT3-ITD cells and maintained histone H3 phosphorylation in response to DNA damage, whereas expression of unphosphorylated Ser 280Ala mutant did not. Finally, FLT3- and Pim-dependent phosphorylation of CHK1 on Ser 280 was confirmed in primary blasts from patients. These results identify a new pathway involved in the resistance of FLT3-ITD leukemic cells to genotoxic agents, and they constitute the first report of CHK1 Ser 280 regulation in myeloid malignancies.

The short form of RON is expressed in acute myeloid leukemia and sensitizes leukemic cells to cMET inhibitors.

Several receptor tyrosine kinases (TKs) are involved in the pathogenesis of acute myeloid leukemia (AML). Here, we have assessed the expression of the Recepteur d'Origine Nantais (RON) in leukemic cell lines and samples from AML patients. In a series of 86 AML patients, we show that both the full length and/or the short form (sf) of RON are expressed in 51% and 43% of cases, respectively. Interestingly, sfRON is not expressed in normal CD34+ hematopoietic cells and induces part of its oncogenic signaling through interaction with the Src kinase Lyn. sfRON-mediated signaling in leukemic cells also involves mTORC1, the proapoptotic bcl2-family member, BAD, but not the phosphatidylinositol 3-kinase/Akt pathway. Furthermore, the expression of sfRON was specifically downregulated by 5-azacytidine (AZA). Conversely, AZA could induce the expression of sfRON in sfRON-negative leukemic cells suggesting that the activity of this drug in AML and myelodysplastic syndromes could involve modulation of TKs. cMET/RON inhibitors exhibited an antileukemic activity exclusively in AML samples and cell lines expressing sfRON. These results might support clinical trials evaluating cMET/RON inhibitors in AML patients expressing sfRON.