Search

Non-T cell activation linker (NTAL) is a lipid raft-membrane protein expressed by normal and leukemic cells and involved in cell signaling. In acute promyelocytic leukemia (APL), NTAL depletion from lipid rafts decreases cell viability through regulation of the Akt/PI3K pathway. The role of NTAL in APL cell processes, and its association with clinical outcome, has not, however, been established. Here, we show that reduced levels of NTAL were associated with increased all-trans retinoic acid (ATRA)-induced differentiation, generation of reactive oxygen species, and mitochondrial dysfunction. Additionally, NTAL-knockdown (NTAL-KD) in APL cell lines led to activation of Ras, inhibition of Akt/mTOR pathways, and increased expression of autophagy markers, leading to an increased apoptosis rate following arsenic trioxide treatment. Furthermore, NTAL-KD in NB4 cells decreased the tumor burden in (NOD scid gamma) NSG mice, suggesting its implication in tumor growth. A retrospective analysis of NTAL expression in a cohort of patients treated with ATRA and anthracyclines, revealed that NTAL overexpression was associated with a high leukocyte count (P = 0.007) and was independently associated with shorter overall survival (Hazard Ratio: 3.6; 95% Confidence Interval: 1.17-11.28; P = 0.026). Taken together, our data highlights the importance of NTAL in APL cell survival and response to treatment.

Although targeted therapies have proven effective and even curative in human leukaemia, resistance often ensues. IDH enzymes are mutated in ~20% of human AML, with targeted therapies under clinical evaluation. We here characterize leukaemia evolution from mutant IDH2 (mIDH2)-dependence to independence identifying key targetable vulnerabilities of mIDH2 leukaemia that are retained during evolution and progression from early to late stages. Mechanistically, we find that mIDH2 leukaemia are metastable and vulnerable at two distinct levels. On the one hand, they are characterized by oxidative and genotoxic stress, in spite of increased 1-carbon metabolism and glutathione levels. On the other hand, mIDH2 leukaemia display inhibition of LSD1 and a resulting transcriptional signature of all-trans retinoic acid (ATRA) sensitization, in spite of a state of suppressed ATRA signalling due to increased levels of PIN1. We further identify GSH/ROS and PIN1/LSD1 as critical nodes for leukaemia maintenance and the combination of ATRA and arsenic trioxide (ATO) as a key therapeutic modality to target these vulnerabilities. Strikingly, we demonstrate that the combination of ATRA and ATO proves to be a powerfully synergistic and effective therapy in a number of mouse and human mIDH1/2 leukemic models. Thus, our findings pave the way towards the treatment of a sizable fraction of human AMLs through targeted APL-like combinatorial therapies.

Prolonged therapy with all-trans-retinoic acid (ATRA) and arsenic trioxide (ATO) is highly effective in newly diagnosed acute promyelocytic leukemia (APL) but there is limited data on the efficacy of this regimen in the relapse setting. We report here on 22 APL patients treated with prolonged ATRA-ATO therapy at the time of disease relapse. Twenty patients obtained molecular complete remission (CRm) after 2 cycles (90%). Of these, two patients underwent hematopoietic stem cell transplant (HSCT) while the remaining proceeded to receive additional cycles (up to a total of 5) of ATRA-ATO. With a median follow-up of 58 months from the time of relapse (range: 21-128 months), the 4-year OS probability was 0.85 (95% CI 0.61-0.94), DFS was 0.74 (95% CI 0.49-0.88), and EFS 0.68 (95% CI 0.45-0.83). Two patients were resistant to ATRA-ATO salvage and five relapsed at a median of 19 months. Of these, four died due to progressive disease while three relapsed achieved a new CRm after further salvage therapy. This experience confirms the potentially curative effect of prolonged ATRA-ATO therapy in relapsed APL, especially in patients with long first complete remission.

Pediatric acute promyelocytic leukemia (APL) can be cured with all- trans retinoic acid (ATRA) and anthracycline. However, most published trials have employed high cumulative doses of anthracyclines. Here, we report the outcome of newly diagnosed APL patients enrolled in the International Consortium for Childhood APL (ICC-APL-01) trial, which reduced anthracycline exposure but extended that of ATRA. The study recruited 258 children/adolescents with molecularly/cytogenetically proven APL. Patients were stratified into standard-risk (SR) and high-risk (HR) groups according to baseline white blood cell counts (<10 × 10 9 /L or ≥10 × 10 9 /L); both groups received identical induction treatment with ATRA and 3 doses of idarubicin. Two or 3 blocks of consolidation therapy were administered to SR and HR patients, respectively, while maintenance therapy with low-dose chemotherapy and ATRA cycles was given to all patients for 2 years. The cumulative dose of daunorubicin equivalent anthracyclines in SR and HR patients was lower than that of previous studies (355 mg/m 2 and 405 mg/m 2 , respectively). Hematologic remission was obtained in 97% of patients; 8 children died of intracranial hemorrhage in the first 2 weeks following diagnosis. Five-year overall and event-free survival for the whole cohort were 94.6% and 79.9%, respectively; they were 98.4% and 89.4% in SR patients and 84.3% and 74.2% in HR patients ( P = .002 and P = .043, respectively). These data demonstrate that extended use of ATRA coupled to a risk-adapted consolidation can achieve high cure rates in childhood APL and limit anthracycline exposure. The trial was registered at www.clinicaltrials.gov as EudractCT 2008-002311-40., (© 2018 by The American Society of Hematology.)

Background: Patients with acute myeloid leukemia (AML) and a FLT3 mutation have poor outcomes. We conducted a phase 3 trial to determine whether the addition of midostaurin - an oral multitargeted kinase inhibitor that is active in patients with a FLT3 mutation - to standard chemotherapy would prolong overall survival in this population., Methods: We screened 3277 patients, 18 to 59 years of age, who had newly diagnosed AML for FLT3 mutations. Patients were randomly assigned to receive standard chemotherapy (induction therapy with daunorubicin and cytarabine and consolidation therapy with high-dose cytarabine) plus either midostaurin or placebo; those who were in remission after consolidation therapy entered a maintenance phase in which they received either midostaurin or placebo. Randomization was stratified according to subtype of FLT3 mutation: point mutation in the tyrosine kinase domain (TKD) or internal tandem duplication (ITD) mutation with either a high ratio (>0.7) or a low ratio (0.05 to 0.7) of mutant to wild-type alleles (ITD [high] and ITD [low], respectively). Allogeneic transplantation was allowed. The primary end point was overall survival., Results: A total of 717 patients underwent randomization; 360 were assigned to the midostaurin group, and 357 to the placebo group. The FLT3 subtype was ITD (high) in 214 patients, ITD (low) in 341 patients, and TKD in 162 patients. The treatment groups were well balanced with respect to age, race, FLT3 subtype, cytogenetic risk, and blood counts but not with respect to sex (51.7% in the midostaurin group vs. 59.4% in the placebo group were women, P=0.04). Overall survival was significantly longer in the midostaurin group than in the placebo group (hazard ratio for death, 0.78; one-sided P=0.009), as was event-free survival (hazard ratio for event or death, 0.78; one-sided P=0.002). In both the primary analysis and an analysis in which data for patients who underwent transplantation were censored, the benefit of midostaurin was consistent across all FLT3 subtypes. The rate of severe adverse events was similar in the two groups., Conclusions: The addition of the multitargeted kinase inhibitor midostaurin to standard chemotherapy significantly prolonged overall and event-free survival among patients with AML and a FLT3 mutation. (Funded by the National Cancer Institute and Novartis; ClinicalTrials.gov number, NCT00651261 .).

The use of high-dose ascorbate (ASC) for the treatment of human cancer has been attempted several decades ago and has been recently revived by several in vitro and in vivo studies in solid tumors. We tested the cytotoxic effects of ASC, alone or in combination with arsenic trioxide (ATO) in acute myeloid leukemia (AML) and acute promyelocytic leukemia (APL). Leukemic cell lines and primary blasts from AML and APL patients were treated with graded concentrations of ASC, alone or in association with standard concentration (1 μM) of ATO. The ASC/ATO combination killed myeloid blasts, including leukemic CD34+ cells, while sparing CD34+ progenitors obtained from normal cord blood and bone marrow. Actually, approximately one-third (11/36) of primary AML cases were highly sensitive to the ASC/ATO combination. The mechanism of cell killing appeared to be related to increased oxidative stress and overproduction of ROS in a non-quantitative fashion, which resulted in induction of apoptosis. These effects were reverted by the addition of the antioxidant N-Acetyl-Cysteine (NAC). In the APL NB4 model, ASC induced direct degradation of the PML and PML/RARA proteins via caspase activation, while the transcriptional repressor DAXX was recruited in re-constituted PML nuclear bodies. Our findings encourage the design of pilot studies to explore the potential clinical benefit of ASC alone or in combination with ATO in advanced AML and APL.

Purpose The initial results of the APL0406 trial showed that the combination of all- trans-retinoic acid (ATRA) and arsenic trioxide (ATO) is at least not inferior to standard ATRA and chemotherapy (CHT) in first-line therapy of low- or intermediate-risk acute promyelocytic leukemia (APL). We herein report the final analysis on the complete series of patients enrolled onto this trial. Patients and Methods The APL0406 study was a prospective, randomized, multicenter, open-label, phase III noninferiority trial. Eligible patients were adults between 18 and 71 years of age with newly diagnosed, low- or intermediate-risk APL (WBC at diagnosis ≤ 10 × 10 9 /L). Overall, 276 patients were randomly assigned to receive ATRA-ATO or ATRA-CHT between October 2007 and January 2013. Results Of 263 patients evaluable for response to induction, 127 (100%) of 127 patients and 132 (97%) of 136 patients achieved complete remission (CR) in the ATRA-ATO and ATRA-CHT arms, respectively ( P = .12). After a median follow-up of 40.6 months, the event-free survival, cumulative incidence of relapse, and overall survival at 50 months for patients in the ATRA-ATO versus ATRA-CHT arms were 97.3% v 80%, 1.9% v 13.9%, and 99.2% v 92.6%, respectively ( P < .001, P = .0013, and P = .0073, respectively). Postinduction events included two relapses and one death in CR in the ATRA-ATO arm and two instances of molecular resistance after third consolidation, 15 relapses, and five deaths in CR in the ATRA-CHT arm. Two patients in the ATRA-CHT arm developed a therapy-related myeloid neoplasm. Conclusion These results show that the advantages of ATRA-ATO over ATRA-CHT increase over time and that there is significantly greater and more sustained antileukemic efficacy of ATO-ATRA compared with ATRA-CHT in low- and intermediate-risk APL.

Introduction: Therapeutic strategies in patients with acute myeloid leukemia (AML) have not changed significantly over the last decades. Appropriate strategies are ultimately driven by the assessment of patients' fitness to define suitability for intensive induction chemotherapy, which produces high initial remission rates but, increased likelihood of relapse. Old/unfit AML patients still represent an urgent and unmet therapeutic need. Epigenetic deregulation represents a strategic characteristic of AML pathophysiology whereby aberrant gene transcription provides an advantage to leukemic cell survival. Efforts to re-establish impaired epigenetic regulation include hypomethylating agents and histone deacetylase inhibitors (HDACi)., Areas Covered: The review discusses the underlying mechanisms leading to disruption of lysine acetyltransferases (KAT or HAT)/deacetylase (KDAC or HDAC) balance and the rationale for using the HDACi panobinostat (LBH-589) in AML., Expert Opinion: Although panobinostat has produced significant results in myeloma, its efficacy remains limited in AML. Panobinostat exerts pleiotropic activity and lack of specificity, which likely contributes to its inadequate safety in elderly AML patients. Phase I-II trials, utilizing panobinostat associated with well-known chemotherapeutic agents are ongoing and combinations with other druggable targets may likely be evaluated in future trials. The clinical use of this HDACi in AML the near future does not appearing promising.

The objective of this study was to estimate the net cost of arsenic trioxide (ATO) added to all-trans retinoic acid (ATRA) compared to ATRA plus chemotherapy when used in first-line acute promyelocytic leukemia (APL) treatment for low to intermediate risk patients from the perspective of the overall Italian healthcare systemA Markov model was developed with 3 health states: stable disease, disease event and death. Each month, patients could move from stable to disease event or die from either state. After a disease event, patients discontinued initial treatment and switched to the other regimen as second-line therapy. Treatment regimens, efficacy and adverse events were derived from published sources and expert opinion; unit costs were collected from standard Italian sources. Clinical outcomes and costs for pre-ATO and post-ATO scenarios were combined with population and product utilization information to calculate the total budgetary impact using a 3-year time horizon; one-way sensitivity analyses were conducted. Three-year cumulative pharmacy costs for ATO+ATRA were €46,700 per-patient versus €6,500 for ATRA+chemotherapy; however, medical costs for ATO+ATRA were €12,300 per-patient versus €30,200 for ATRA+chemotherapy. The total budgetary impact was estimated to be an additional €127,300, €312,500 and €477,800 in the first, second and third years, respectively. The model was most sensitive to changes in the cost of the ATO+ATRA regimen during the consolidation phase. Budgetary impact models are valuable to payers making formulary decisions regarding the access and affordability of new medicines. The cost of treatment analysis showed that pharmacy costs for ATO+ATRA were higher than for ATRA+chemotherapy, while all other evaluated costs were lower for ATO+ATRA treated patients. The average budgetary impact was €305,900 per year overall, representing a 3.5% increase. Further research is needed to determine the cost-effectiveness of ATO+ATRA compared to the current first-line standard of care in APL.

Front-line treatment of acute promyelocytic leukaemia (APL) consists of all-trans retinoic acid (ATRA) and anthracycline-based chemotherapy. In this setting, a comparison of idarubicin and daunorubicin has never been carried out. Two similar clinical trials using ATRA and chemotherapy for newly diagnosed APL were compared using matched-pair analysis. One was conducted by the PETHEMA/HOVON group with idarubicin and the other by the International Consortium on APL (IC-APL) using daunorubicin. Three hundred and fifty patients from the PETHEMA/HOVON cohort were matched with 175 patients in the IC-APL cohort, adjusting for the significantly unbalanced presenting features of the two entire cohorts. Complete remission (CR) rate was significantly higher in the PETHEMA/HOVON (94 %) than in the IC-APL cohort (85 %) (P = 0.002). The distribution of causes of induction failure and the time to achieve CR were similar in both cohorts. Patients who achieved CR had comparable cumulative incidence of relapse and disease-free survival rates, but lower overall and event-free survivals were observed in the IC-APL cohort, which was mainly due to a higher death rate during induction therapy. A higher death rate during consolidation therapy was also observed in the IC-APL. These results show that daunorubicin and idarubicin have similar antileukaemic efficacy in terms of primary resistance, molecular persistence, as well as molecular and haematological relapse rates when combined with ATRA in treatment of APL. However, a higher toxic death rate during induction and consolidation therapy was observed in the IC-APL cohort. This trial was registered at www.clinicaltrials.gov as #NCT00408278 [ClinicalTrials.gov].

We assessed by flow cytometry minimal residual disease (MRD) in patients with acute myeloid leukemia (AML) given standard-dose (SDAC) and high-dose ARA-C (HDAC) regimens. Of 163 patients enrolled, 130 (median age, 45 years; range, 18-59 years) qualified for analysis, all achieving complete remission after treatment with SDAC (n = 78) or HDAC (n = 52) plus etoposide and daunorubicin. Consolidation consisted of intermediate-dose ARA-C and daunorubicin. MRD negativity was significantly more frequent in the SDAC vs. HDAC arm after both induction (37% vs. 15%, P = 0.007) and consolidation (44% vs. 18%, P = 0.002). Respective median residual leukemic cell counts with SDAC and HDAC use were 1.5 × 10(-3) and 4 × 10(-3) (P = 0.033) after induction and 5.7 × 10(-4) and 2.9 × 10(-3) (P = 0.008) after consolidation. Based on ARA-C schedule and post-consolidation MRD status, the four patient groups (SDAC-MRD(-) , HDAC-MRD(-) , SDAC-MRD(+) , and HDAC-MRD(+) ) displayed 5-year overall survival rates of 60%, 33%, 24%, and 42% (P = 0.007), respectively, with 24%, 35%, 74%, and 48% (P < 0.0001) respective cumulative incidence of relapse estimates. MRD may serve as a biomarker for optimal biologic dosing of ARA-C, and SDAC regimen appears to yield more frequent MRD negativity., (© 2014 Wiley Periodicals, Inc.)

All-trans retinoic acid (ATRA) has made acute promyelocytic leukemia (APL) a very curable disease also in patients aged >60 years; however, there are only few case reports in very elderly APL patients. To address this issue, we reviewed treatment results in 13 patients aged >70 years with newly diagnosed APL followed at our institution from January 1991 to December 2008. According to Sanz score, seven patients were at low risk, five at intermediate risk, and one at high risk. Induction therapy consisted of ATRA + idarubicin in nine patients (3/9 with reduced idarubicin dosage) and ATRA alone in four patients; in this latter group, however, 2/4 needed to add chemotherapy (CHT) due to hyperleukocytosis during ATRA treatment. All patients achieved both morphological and molecular complete remission (CR) after a median time of 51 [interquartile range (IR) 43-55] and 114 (IR 74-155) days, respectively. Infective complications were observed in 10/13 patients, APL differentiation syndrome in 3/13 patients. Twelve patients received consolidation therapy, followed by maintenance treatment in nine patients. Five patients relapsed after 7, 8, 11, 35, and 56 months. At present, seven patients are still alive, five died due to disease progression (four) or senectus while in CR (one), and one was lost to follow-up while in CR. The 5-year event-free survival was 56.1 % (95 % CI, 26.0-86.2); the 5-year overall survival (OS) was 64.5 % (95 % CI, 35.6-93.4). ATRA-based treatment of APL is safe and effective also in very elderly patients, with long-lasting disease-free OS.

Activating internal tandem duplication (ITD) mutations in the fms-like tyrosine kinase 3 (FLT3) gene (FLT3-ITD) are associated with poor outcome in acute myeloid leukemia, but their prognostic impact in acute promyelocytic leukemia (APL) remains controversial. Here, we screened for FLT3-ITD mutations in 171 APL patients, treated with all-trans retinoic acid (ATRA) and anthracycline-based chemotherapy. We identified FLT3-ITD mutations in 35 patients (20 %). FLT3-ITD mutations were associated with higher white blood cell counts (P < 0.0001), relapse-risk score (P = 0.0007), higher hemoglobin levels (P = 0.0004), higher frequency of the microgranular morphology (M3v) subtype (P = 0.03), and the short PML/RARA (BCR3) isoform (P < 0.0001). After a median follow-up of 38 months, FLT3-ITD(positive) patients had a lower 3-year overall survival rate (62 %) compared with FLT3-ITD(negative) patients (82 %) (P = 0.006). The prognostic impact of FLT3-ITD on survival was retained in multivariable analysis (hazard ratio: 2.39, 95 % confidence interval [CI] 1.17-4.89; P = 0.017). Nevertheless, complete remission (P = 0.07), disease-free survival (P = 0.24), and the cumulative incidence of relapse (P = 0.94) rates were not significantly different between groups. We can conclude that FLT3-ITD mutations are associated with several hematologic features in APL, in particular with high white blood cell counts. In addition, FLT3-ITD may independently predict a shorter survival in patients with APL treated with ATRA and anthracycline-based chemotherapy.

Purpose: A randomized clinical trial compared efficacy and toxicity of standard all-trans-retinoic acid (ATRA) plus chemotherapy versus ATRA plus arsenic trioxide in patients with newly diagnosed, low- or intermediate-risk acute promyelocytic leukemia (APL). Here, we report health-related quality-of-life (HRQOL) results., Patients and Methods: HRQOL was a secondary end point of this trial. The European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-Core 30 was used to assess HRQOL at end of induction and after consolidation therapy. All analyses were based on 156 patients who received at least one dose of treatment, with groups defined according to randomly assigned treatment. Primary analysis was performed, estimating mean HRQOL score over time and differences between treatment arms using a linear mixed model., Results: Overall, 162 patients age 18 to 70 years were enrolled. Of these, 150 and 142 patients were evaluable for HRQOL after induction therapy and third consolidation course, respectively. Overall compliance with HRQOL forms was 80.1%. The largest difference, favoring patients treated with ATRA plus arsenic trioxide, was found for fatigue severity (mean score difference, -9.3; 95% CI, -17.8 to -0.7; P = .034) at end of induction therapy. This difference was also clinically relevant. HRQOL differences between treatment arms at end of consolidation showed that for several scales, differences between treatment arms were marginal., Conclusion: Overall, current HRQOL findings further support the use of ATRA plus arsenic trioxide as preferred first-line treatment in patients with low- or intermediate-risk APL., (© 2014 by American Society of Clinical Oncology.)

The KMT2E (MLL5) gene encodes a histone methyltransferase implicated in the positive control of genes related to haematopoiesis. Its close relationship with retinoic acid-induced granulopoiesis suggests that the deregulated expression of KMT2E might lead acute promyelocytic leukaemia (APL) blasts to become less susceptible to the conventional treatment protocols. Here, we assessed the impact of KMT2E expression on the prognosis of 121 APL patients treated with ATRA and anthracycline-based chemotherapy. Univariate analysis showed that complete remission (P = 0·006), 2-year overall survival (OS) (P = 0·005) and 2-year disease-free survival (DFS) rates (P = 0·037) were significantly lower in patients with low KMT2E expression; additionally, the 2-year cumulative incidence of relapse was higher in patients with low KMT2E expression (P = 0·04). Multivariate analysis revealed that low KMT2E expression was independently associated with lower remission rate (odds ratio [OR]: 7·18, 95% confidence interval [CI]: 1·71-30·1; P = 0·007) and shorter OS (hazard ratio [HR]: 0·27, 95% CI: 0·08-0·87; P = 0·029). Evaluated as a continuous variable, KMT2E expression retained association with poor remission rate (OR: 10·3, 95% CI: 2·49-43·2; P = 0·001) and shorter survival (HR: 0·17, 95% IC: 0·05-0·53; P = 0·002), while the association with DFS was of marginal significance (HR: 1·01; 95% CI: 0·99-1·02; P = 0·06). In summary, low KMT2E expression may predict poor outcome in APL patients., (© 2014 John Wiley & Sons Ltd.)

Modern guidelines based on a large international consensus indicate that treatment of newly diagnosed acute promyelocytic leukemia (APL) requires distinguishing at presentation low-intermediate (<10 × 10(9)/L WBC) from high-risk (>10 × 10(9)/L WBC) disease. The concomitant use of all-trans retinoic acid (ATRA) and anthracycline based chemotherapy, with inclusion of AraC in consolidation for hyperleucocytic patients, has remained the standard of care for the past two decades. The advent of arsenic trioxide (ATO) and results from a large randomized trial, have recently challenged the standard ATRA-chemotherapy approach suggesting that at least patients in the low-intermediate category may be cured without chemotherapy using the ATRA-ATO combination.

Purpose of Review: Arsenic trioxide (ATO) has been shown to be the most effective single agent in acute promyelocytic leukaemia (APL) and has been approved for the treatment of relapsed patients both in the US and Europe. The role of ATO in front-line therapy of APL is under investigation., Recent Findings: Pilot studies using ATO with or without all-trans retinoic acid (ATRA) have been carried out in newly diagnosed APL patients with the aim to reduce the short and long-term toxic effects of chemotherapy and to improve clinical outcome. Especially in patients with non-high-risk APL, the ATRA + ATO approach allowed significant increase in event-free survival and overall survival rates compared to standard ATRA and chemotherapy. This has been demonstrated by pilot studies and, more recently, by a randomized comparative multi-centre study conducted in Italy and Germany., Summary: The ATO + ATRA strategy for APL may provide the first paradigm of acute leukaemia curability by targeted agents and without chemotherapy. However, longer follow-up of available studies and independent confirmation of the Italian-German findings are awaited to firmly establish this paradigm. Finally, extension of this approach to other patient categories such as high-risk, elderly and children will need to be explored in the near future.

Alterations in hematopoietic microenvironment of acute lymphoblastic leukemia patients have been claimed to occur, but little is known about the components of marrow stroma in these patients. In this study, we characterized mesenchymal stromal cells (MSCs) isolated from bone marrow (BM) of 45 pediatric patients with acute lymphoblastic leukemia (ALL-MSCs) at diagnosis (day+0) and during chemotherapy treatment (days: +15; +33; +78), the time points being chosen according to the schedule of BM aspirates required by the AIEOP-BFM ALL 2009 treatment protocol. Morphology, proliferative capacity, immunophenotype, differentiation potential, immunomodulatory properties and ability to support long-term hematopoiesis of ALL-MSCs were analysed and compared with those from 41 healthy donors (HD-MSCs). ALL-MSCs were also genetically characterized through array-CGH, conventional karyotyping and FISH analysis. Moreover, we compared ALL-MSCs generated at day+0 with those isolated during chemotherapy. Morphology, immunophenotype, differentiation potential and in vitro life-span did not differ between ALL-MSCs and HD-MSCs. ALL-MSCs showed significantly lower proliferative capacity (p<0.001) and ability to support in vitro hematopoiesis (p = 0.04) as compared with HD-MSCs, while they had similar capacity to inhibit in vitro mitogen-induced T-cell proliferation (p = N.S.). ALL-MSCs showed neither the typical translocations carried by the leukemic clone (when present), nor other genetic abnormalities acquired during ex vivo culture. Our findings indicate that ALL-MSCs display reduced ability to proliferate and to support long-term hematopoiesis in vitro. ALL-MSCs isolated at diagnosis do not differ from those obtained during treatment.

Background: All-trans retinoic acid (ATRA) with chemotherapy is the standard of care for acute promyelocytic leukemia (APL), resulting in cure rates exceeding 80%. Pilot studies of treatment with arsenic trioxide with or without ATRA have shown high efficacy and reduced hematologic toxicity., Methods: We conducted a phase 3, multicenter trial comparing ATRA plus chemotherapy with ATRA plus arsenic trioxide in patients with APL classified as low-to-intermediate risk (white-cell count, ≤10×10(9) per liter). Patients were randomly assigned to receive either ATRA plus arsenic trioxide for induction and consolidation therapy or standard ATRA-idarubicin induction therapy followed by three cycles of consolidation therapy with ATRA plus chemotherapy and maintenance therapy with low-dose chemotherapy and ATRA. The study was designed as a noninferiority trial to show that the difference between the rates of event-free survival at 2 years in the two groups was not greater than 5%., Results: Complete remission was achieved in all 77 patients in the ATRA-arsenic trioxide group who could be evaluated (100%) and in 75 of 79 patients in the ATRA-chemotherapy group (95%) (P=0.12). The median follow-up was 34.4 months. Two-year event-free survival rates were 97% in the ATRA-arsenic trioxide group and 86% in the ATRA-chemotherapy group (95% confidence interval for the difference, 2 to 22 percentage points; P<0.001 for noninferiority and P=0.02 for superiority of ATRA-arsenic trioxide). Overall survival was also better with ATRA-arsenic trioxide (P=0.02). As compared with ATRA-chemotherapy, ATRA-arsenic trioxide was associated with less hematologic toxicity and fewer infections but with more hepatic toxicity., Conclusions: ATRA plus arsenic trioxide is at least not inferior and may be superior to ATRA plus chemotherapy in the treatment of patients with low-to-intermediate-risk APL. (Funded by Associazione Italiana contro le Leucemie and others; ClinicalTrials.gov number, NCT00482833.).

Despite the impressive results obtained with standard chemotherapy, approximately 20% of acute promyelocytic leukemia (APL) patients undergo disease relapse thereby requiring salvage therapy. Few data is available on long-term prognosis in relation to time to complete remission (CR): we reviewed 142 patients treated with AIDA protocols and we found that 42 out of 142 (29.6%) patients achieved CR after 35 days (median time, 42 days). No significant differences in presenting features, including FAB subtype, type of PML/RARA transcript and relapse risk at presentation between the two patient groups achieving CR > or <35 days were revealed, except for male sex and older age that were significantly associated with delayed CR. Rate of relapse was 31% in patients with delayed CR compared to 17% in the group of patients who achieved CR<35 days (p=0.001), with a 5-year CIR of 29.6% compared to 12% (p=0.03). APL patients with delayed CR should be more closely monitored during follow-up for early identification of relapse and prompt administration of pre-emptive salvage therapy., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

We investigated whether body mass index (BMI) correlates with distinct outcomes in newly diagnosed acute promyelocytic leukemia (APL). The study population included 144 patients with newly diagnosed and genetically confirmed APL consecutively treated at a single institution. All patients received All-trans retinoic acid and idarubicin according to the GIMEMA protocols AIDA-0493 and AIDA-2000. Outcome estimates according to the BMI were carried out together with multivariable analysis for the risk of relapse and differentiation syndrome. Fifty-four (37.5%) were under/normal weight (BMI < 25), whereas 90 (62.5%) patients were overweight/obese (BMI ≥ 25). An increased BMI was associated with older age (P < .0001) and male sex (P = .02). BMI was the most powerful predictor of differentiation syndrome in multivariable analysis (odds ratio = 7.24; 95% CI, 1.50-34; P = .014). After a median follow-up of 6 years, the estimated cumulative incidence of relapse at 5 years was 31.6% (95% CI, 22.7%-43.8%) in overweight/obese and 11.2% (95% CI, 5.3%-23.8%) in underweight/normal weight patients (P = .029). Multivariable analysis showed that BMI was an independent predictor of relapse (hazard ratio = 2.45, 95% CI, 1.00-5.99, in overweight/obese vs under/normal weight patients, P = .049). An increased BMI at diagnosis is associated with a higher risk of developing differentiation syndrome and disease relapse in APL patients treated with AIDA protocols.

To reduce toxicity in elderly patients with acute promyelocytic leukaemia, in 1997 the Gruppo Italiano Malattie Ematologiche Dell'Adulto (GIMEMA) started an amended protocol for patients aged >60years, with the same induction [all-trans retinoic acid (ATRA)+idarubicin] as in younger patients, followed by a single consolidation course (idarubicin+ cytarabine) and maintenance with intermittent ATRA. Among 60 enrolled patients, 54 (90%) achieved haematological remission and six died during induction. Four additional patients died in complete remission (CR) from haemorrhage (2) and infection (2) prior or during consolidation therapy. Eleven patients relapsed at a median time of 17·5months from CR. The 5-year overall survival (OS), disease-free survival (DFS) and cumulative incidence of relapse (CIR) rates were 76·1%, 64·6% and 27·4%, respectively. Univariate analysis identified a performance score (PS)=2 as the only significant adverse prognostic factor for both OS (P=0·017) and DFS (P=0·0003). Male sex had an unfavourable impact on DFS (P=0·021) and on CIR (P=0·019), but not on OS (P=0·234). In multivariate analysis for DFS, only PS=2 retained prognostic significance (HR=4·5, P=0·0083). In conclusion, the amended GIMEMA protocol is effective, with similar relapse rate and inferior toxicity compared to the original AIDA 0493. However, considering the recent availability of effective new agents, a less aggressive approach should be tested in this setting., (© 2011 Blackwell Publishing Ltd.)

All-trans-retinoic acid (ATRA) has greatly modified the prognosis of acute promyelocytic leukemia; however, the role of maintenance in patients in molecular complete remission after consolidation treatment is still debated. From July 1993 to May 2000, 807 genetically proven newly diagnosed acute promyelocytic leukemia patients received ATRA plus idarubicin as induction, followed by 3 intensive consolidation courses. Thereafter, patients reverse-transcribed polymerase chain reaction-negative for the PML-RARA fusion gene were randomized into 4 arms: oral 6-mercaptopurine and intramuscular methotrexate (arm 1); ATRA alone (arm 2); 3 months of arm1 alternating to 15 days of arm 2 (arm 3); and no further therapy (arm 4). Starting from February 1997, randomization was limited to ATRA-containing arms only (arms 2 and 3). Complete remission was achieved in 761 of 807 (94.3%) patients, and 681 completed the consolidation program. Of these, 664 (97.5%) were evaluated for the PML-RARA fusion gene, and 586 of 646 (90.7%) who tested reverse-transcribed polymerase chain reaction-negative were randomized to maintenance. The event-free survival estimate at 12 years was 68.9% (95% confidence interval, 66.4%-71.4%), and no differences in disease-free survival at 12 years were observed among the maintenance arms.

After the identification of discrete relapse-risk categories in patients with acute promyelocytic leukemia (APL) receiving all-trans retinoic and idarubicin (AIDA)-like therapies, the Gruppo Italiano Malattie Ematologiche dell'Adulto (GIMEMA) designed a protocol for newly diagnosed APL (AIDA-2000) in which postremission treatment was risk-adapted. Patients with low/intermediate risk received remission at 3 anthracycline-based consolidation courses, whereas high-risk patients received the same schedule as in the previous, non-risk-adapted AIDA-0493 trial including cytarabine. In addition, all patients in the AIDA-2000 received all-trans retinoic acid (ATRA) for 15 days during each consolidation. After induction, 600 of 636 (94.3%) and 420 of 445 (94.4%) patients achieved complete remission in the AIDA-0493 and AIDA-2000, respectively. The 6-year overall survival and cumulative incidence of relapse (CIR) rates were 78.1% versus 87.4% (P = .001) and 27.7% versus 10.7% (P < .0001). Significantly lower CIR rates for patients in the AIDA-2000 were most evident in the high-risk group (49.7% vs 9.3%, respectively, P < .0001). Our data confirm that anthracycline-based consolidation is at least equally effective as cytarabine-containing regimens for low-/intermediate-risk patients and suggest that a risk-adapted strategy including ATRA for consolidation improves outcome in newly diagnosed APL. Furthermore, our results highlight the role of cytarabine coupled to anthracyclines and ATRA during consolidation in the high-risk group.

Background: Clinical trials of monoclonal antibodies in combination with chemotherapy have reported previously unattained response rates in patients with B-cell chronic lymphocytic leukemia (B-CLL); however, the analysis of ZAP-70 protein and/or CD38 may explain better the discordant outcomes independent of treatment., Methods: The authors conducted a Phase II study, in which rituximab was added to fludarabine for patients with symptomatic, untreated CLL, to evaluate clinical outcomes. Sixty patients with B-CLL received 6 monthly courses of fludarabine (25 mg/m(2) for 5 days) followed by 4 weekly doses of rituximab (375 mg/m(2))., Results: On the basis of National Cancer Institute criteria, 47 of 60 patients (78%) achieved a complete remission, 9 of 60 patients (15%) achieved a partial remission, and 4 of 60 patients (7%) had no response or progressive disease. It is noteworthy that the patients experienced a long progression-free survival (PFS) from treatment (68% at 3 yrs). A significantly shorter PFS was observed in ZAP-70-positive patients (25% vs. 100% at 3 yrs; P = 0.00005), in CD38-positive patients (18% vs. 91% at 3 yrs; P = 0.0002), and in patients who had more minimal residual disease (36% vs. 77% at 2.5 yrs; P = 0.001)., Conclusions: With the addition of rituximab to fludarabine, improved clinical outcomes were obtained, and the stratification of patients by using ZAP-70 and CD38 may help clinicians offer more aggressive and/or experimental approaches to the treatment of patients with high-risk B-CLL subtypes., (Copyright 2005 American Cancer Society.)

The role of all-trans retinoic acid (ATRA) in pediatric acute promyelocytic leukemia (APL) is the topic of several ongoing studies. The results of the Italian pediatric experience with the multicentric Gruppo Italiano per le Malattie Ematologiche dell'Adulto (GIMEMA)-Italian Pediatric Hematology and Oncology Group (AIEOP) "AIDA" (ATRA and idarubicin) trial are presented. Of the 983 patients with APL enrolled in this protocol between January 1993 and June 2000, 124 (13%) had younger than 18 years. Treatment consisted of ATRA and idarubicin induction followed by 3 polychemotherapy consolidation courses. Molecular response by reverse transcriptase-polymerase chain reaction (RT-PCR) was assessed after consolidation and patients who were PCR- were randomized for different maintenances. One hundred and seven children were eligible and evaluable for induction: 103 (96%) achieved a hematologically complete remission. Overt ATRA syndrome was observed in 2 patients and pseudotumor cerebri was observed in 10 patients. Ninety-four patients were evaluable for RT-PCR analysis at the end of consolidation: 91 (97%) proved PCR+ and 3 PCR-. The overall survival and event-free survival (EFS) are 89% (95% confidence interval [c.i.]: 83%-95%) and 76% (c.i.: 65%-85%), respectively, at more than 10 years. A white blood cell (WBC) count at diagnosis of greater than 10 x 10(9)/L had a significant impact on EFS (59% vs 83% at 10 years). These results highlight the efficacy and feasibility of the AIDA protocol in the pediatric APL population.

Background and Objectives: Front line treatment of acute promyelocytic leukemia (APL) with all-trans retinoic acid (ATRA) and chemotherapy (CHT) results in molecular remission in approximately 95% of patients tested after consolidation. The small fraction of patients with persistence of molecular disease (i.e. those in whom polymerase chain reaction (PCR) is positive for PML/RARalpha) after such therapy are thought to have a dismal prognosis but has not yet been investigated in detail., Design and Methods: We analyzed the clinico-biological features at presentation of APL patients who showed PCR-detectable residual disease and compared them to those of patients achieving molecular remission after AIDA induction and consolidation. Furthermore, we report the outcome of patients with molecularly persistent disease treated with salvage therapy., Results: Patients attaining molecular remission (n=650) and patients who tested PCR+ve at the end of consolidation (n=23) were not statistically significantly different as regards median age, white cell and platelet counts, morphologic subtype (M3 or M3v), fibrinogen levels or PML/RARalpha transcript type. As to treatment outcome after salvage therapy, 7 patients were treated before morphologic relapse [3 with chemotherapy and autologous stem cell transplantation (SCT) and 4 with allogeneic SCT], and are alive after 64-118 months. Of 16 patients treated at the time of morphologic relapse, only 2 patients are alive, both of whom received an allogeneic SCT., Interpretation and Conclusions: Our findings indicate that APL patients who are molecularly resistant to the AIDA protocol have no distinguishing features at presentation. Their outcome suggests the need for early therapeutic intervention with aggressive treatment prior to the occurrence of hematologic relapse.

Acute leukemia with the t(11;17) expressing the PLZF-RARalpha gene fusion is a rare variant of acute promyelocytic leukemia (APL) that has been associated with poor clinical response to all-trans retinoic acid (ATRA) treatment. However, some recent reports have put into question the absolute refractoriness of this leukemia to ATRA. We describe here a patient with PLZF/RARalpha APL who was treated at relapse with ATRA and low-dose hydroxyurea. Complete hematologic remission was obtained through differentiation of leukemic blasts, as proven by morphologic, immunophenophenotypic, and genetic studies carried out in sequential bone marrow samples. Moreover, in vitro studies indicated that blast differentiation was potentiated by the addition of the histone deacetylase inhibitor tricostatin A, but not of hydroxyurea, to ATRA. Our findings indicate that the maturation block may be overcome and terminal differentiation obtained in this leukemia subset and support the view that sensitivity/refractoriness of this form to ATRA should be revisited.