Criteria for defining a complete remission in acute myeloid leukaemia revisited. An analysis of patients treated in HOVON-SAKK co-operative group studies

Azacitidine and gemtuzumab ozogamicin as post-transplant maintenance therapy for high-risk hematologic malignancies

Disease recurrence remains the principal cause of treatment failure after allogeneic hematopoietic stem cell transplantation. Post-transplant maintenance therapy with azacitidine (AZA) is promising to prevent relapse but the outcomes are unsatisfactory in patients at high risk of recurrence. Herein, we evaluated the outcome in patients who received AZA and gemtuzumab ozogamicin (GO), anti-CD33 antibody-calicheamicin conjugate, as post-transplant maintenance therapy. Twenty-eight patients with high-risk hematologic malignancies harboring CD33-positive leukemic blasts received the maintenance therapy. AZA (30 mg/m2) was administered for 7 days, followed by GO (3 mg/m2) on day 8. The maximum number of cycles was 4. At transplant, 21 patients (75.0%) had active disease. Their 2-year overall survival, disease-free survival, relapse, and non-relapse mortality rates were 53.6%, 39.3%, 50.0%, and 10.7%, respectively. Of these patients, those with minimal residual disease at the start of maintenance therapy (n = 9) had a higher recurrence rate (66.7% vs. 42.1% at 2 years, P = 0.069) and shorter disease-free survival (11.1% vs. 52.6% at 2 years, P = 0.003). Post-transplant maintenance therapy with AZA and GO was generally tolerable but more than half of the patients eventually relapsed. Further improvements are needed to prevent relapse after transplantation in patients with high-risk hematologic malignancies.

Posaconazole and midostaurin in patients with FLT3-mutated acute myeloid leukemia: Pharmacokinetic interactions and clinical facts in a real life study

Midostaurin is used in combination with chemotherapy to treat patients with newly diagnosed FLT3-mutated acute myeloid leukemia. Chemotherapy-induced neutropenia exposes these patients to a significant risk of invasive fungal infections (IFIs). International guidelines recommend primary antifungal prophylaxis with posaconazole (PCZ) but nested analysis of a phase III trial showed that strong PCZ inhibition of CYP3A4 diminished midostaurin metabolism and increased midostaurin plasma levels; however, midostaurin-related adverse events (AEs) were only moderately exacerbated. We conducted a prospective multicenter real-life study to evaluate (i) how often concerns around PCZ-midostaurin interactions made the hematologist prescribe antifungals other than PCZ, (ii) how remarkably PCZ increased midostaurin plasma levels, and (iii) how significantly PCZ-midostaurin interactions influenced hematologic and safety outcomes of induction therapy. Although the hematologists were blinded to pharmacokinetic findings, as many as 16 of 35 evaluable patients were prescribed antifungal prophylaxis with micafungin, weak CYP3A4 inhibitor, in place of PCZ (p < 0.001 for deviation from guidelines). In the 19 patients managed as per guidelines, PCZ-midostaurin interactions were more remarkable than previously characterized, such that at the end of induction therapy midostaurin minimum plasma concentration (Cmin ) was greater than three times higher than reported; moreover, midostaurin Cmin , maximum plasma concentration, and area under the curve were more than or equal to four times higher with PCZ than micafungin. Hematologic outcomes (complete remission and duration of severe neutropenia) and safety outcomes (midostaurin-related any grade or grade ≥3 AEs) were nonetheless similar for patients exposed to PCZ or micafungin, as was the number of breakthrough IFIs. In waiting for randomized phase III trials of new prophylaxis regimens, these findings show that PCZ should remain the antifungal of choice for the midostaurin-treated patient.

Phase II trial of hypomethylating agent combined with nivolumab for acute myeloid leukaemia relapse after allogeneic haematopoietic cell transplantation-Immune signature correlates with response

Acute myeloid leukaemia (AML) relapse after allogeneic haematopoietic cell transplantation (allo-HCT) is often driven by immune-related mechanisms and associated with poor prognosis. Immune checkpoint inhibitors combined with hypomethylating agents (HMA) may restore or enhance the graft-versus-leukaemia effect. Still, data about using this combination regimen after allo-HCT are limited. We conducted a prospective, phase II, open-label, single-arm study in which we treated patients with haematological AML relapse after allo-HCT with HMA plus the anti-PD-1 antibody nivolumab. The response was correlated with DNA-, RNA- and protein-based single-cell technology assessments to identify biomarkers associated with therapeutic efficacy. Sixteen patients received a median number of 2 (range 1-7) nivolumab applications. The overall response rate (CR/PR) at day 42 was 25%, and another 25% of the patients achieved stable disease. The median overall survival was 15.6 months. High-parametric cytometry documented a higher frequency of activated (ICOS+ , HLA-DR+ ), low senescence (KLRG1- , CD57- ) CD8+ effector T cells in responders. We confirmed these findings in a preclinical model. Single-cell transcriptomics revealed a pro-inflammatory rewiring of the expression profile of T and myeloid cells in responders. In summary, the study indicates that the post-allo-HCT HMA/nivolumab combination induces anti-AML immune responses in selected patients and could be considered as a bridging approach to a second allo-HCT. Trial-registration: EudraCT-No. 2017-002194-18.

Genomic Alterations, Gene Expression Profiles and Functional Enrichment of Normal-Karyotype Acute Myeloid Leukaemia Based on Targeted Next-Generation Sequencing

Characterising genomic variants is paramount in understanding the pathogenesis and heterogeneity of normal-karyotype acute myeloid leukaemia (AML-NK). In this study, clinically significant genomic biomarkers were ascertained using targeted DNA sequencing and RNA sequencing on eight AML-NK patients' samples collected at disease presentation and after complete remission. In silico and Sanger sequencing validations were performed to validate variants of interest, and they were followed by the performance of functional and pathway enrichment analyses for overrepresentation analysis of genes with somatic variants. Somatic variants involving 26 genes were identified and classified as follows: 18/42 (42.9%) as pathogenic, 4/42 (9.5%) as likely pathogenic, 4/42 (9.5%) as variants of unknown significance, 7/42 (16.7%) as likely benign and 9/42 (21.4%) as benign. Nine novel somatic variants were discovered, of which three were likely pathogenic, in the CEBPA gene with significant association with its upregulation. Transcription misregulation in cancer tops the affected pathways involving upstream genes (CEBPA and RUNX1) that were deregulated in most patients during disease presentation and were closely related to the most enriched molecular function gene ontology category, DNA-binding transcription activator activity RNA polymerase II-specific (GO:0001228). In summary, this study elucidated putative variants and their gene expression profiles along with functional and pathway enrichment in AML-NK patients.

Evaluation of CDCP1 (CD318) and endoglin (CD105) expression as prognostic markers in acute myeloid leukemia

BACKGROUND: The most commonly used prognostic factors in acute myeloid leukemia (AML) are cytogenetic, molecular, and morphological markers. However, AML prognosis is still unfavorable particularly in adults. So, further reliable markers are urgently needed to improve the risk stratification and treatment decisions. CUB domain-containing protein 1 (CDCP1; CD318) and endoglin (CD105) are new markers correlated with poor prognosis in different solid tumors, but their role in AML prognosis is not fully evaluated. OBJECTIVES: This work aimed to evaluate the prognostic role of CD318 and CD105 in AML and their impact on the outcomes. METHODS: Sixty-five newly diagnosed AML patients were included in this study. CD318 and CD105 expression was assessed by quantitative real-time polymerase chain reaction. Patients were followed up for ∼ 2 years to evaluate the prognostic impact of gene expression on the outcomes. RESULTS: Patients with high CD318 and CD105 showed higher white blood cell (WBC) count, M2 subtype, poor cytogenetic risk, reduced complete remission, and a greater number of deaths compared to low CD318 and CD105. CD318 was correlated with CD105, and both were correlated with WBC count, bone marrow blasts, and peripheral blood blasts. After a follow-up period of up to 24 months, relapse-free survival for high CD318 and CD105 was significantly different (42.1% and 52.6% vs. 64.5% and 58.1% for low CD318 and CD105, respectively). Survival was worse in patients with high CD318 and CD105, as the mean survival time was 13.9 and 13.3 months compared to 24 and 22.7 months in low CD318 and CD105, respectively. CONCLUSIONS: CD318 and CD105 are upregulated in AML patients. Their overexpression was associated with poor response to treatment and poor outcomes. Therefore, CD318 and CD105 can be useful prognostic markers in AML.

Treatment of acute erythroleukaemia with high-dose cytarabine in a cat with feline leukaemia virus infection

Erythroleukaemia is a malignant neoplasm of the erythroid lineage that rarely occurs in cats. It is associated with the feline leukaemia virus (FeLV), and owing to the poor prognosis, treatment is rarely reported. A 4-year-old female Korean domestic shorthair cat was presented with hyporexia, fever, lethargy, severe anaemia and rubricytosis. An FeLV antigen test was positive, but a subsequent polymerase chain reaction test was negative. Serum biochemistry analysis results were normal, except for slightly elevated alanine aminotransferase. The patient was tentatively diagnosed with acute erythroleukaemia, and single high-dose (600 mg/m² ) cytarabine chemotherapy was administered via constant rate infusion for 12 h a day for 5 days. After the first cytarabine administration, the clinical signs and anaemia improved, though no change was noted to other haematological parameters. The patient died of shock 16 days after the second cytarabine administration; the total survival time after diagnosis was 67 days. Post-mortem cytological evaluation of bone marrow aspiration revealed that the myeloid/erythroid ratio was 0.49, the erythroid progenitor cells were 64% of all nucleated cells and the blast cells were 84% of the non-erythroid cells. Histopathology images indicated that the spleen was diffusely expanded by atypical round cells, possibly erythroid precursors. This is the first case report on the prognosis and effects of high-dose cytarabine chemotherapy for acute feline erythroleukaemia with FeLV infection. Although the clinical signs improved, the treatment was not effective. Further studies on erythroleukaemia chemotherapy protocols are required.

Transcript-Level Dysregulation of BCL2 Family Genes in Acute Myeloblastic Leukemia

The expression of apoptosis-related BCL2 family genes, fine-tuned in normal cells, is dysregulated in many neoplasms. In acute myeloid leukemia (AML), this problem has not been studied comprehensively. To address this issue, RNA-seq data were used to analyze the expression of 26 BCL2 family members in 27 AML FAB M1 and M2 patients, divided into subgroups differently responding to chemotherapy. A correlation analysis, analysis of variance, and Kaplan-Meier analysis were applied to associate the expression of particular genes with other gene expression, clinical features, and the presence of mutations detected by exome sequencing. The expression of BCL2 family genes was dysregulated in AML, as compared to healthy controls. An upregulation of anti-apoptotic and downregulation of pro-apoptotic genes was observed, though only a decrease in BMF, BNIP1, and HRK was statistically significant. In a group of patients resistant to chemotherapy, overexpression of BCL2L1 was manifested. In agreement with the literature data, our results reveal that BCL2L1 is one of the key players in apoptosis regulation in different types of tumors. An exome sequencing data analysis indicates that BCL2 family genes are not mutated in AML, but their expression is correlated with the mutational status of other genes, including those recurrently mutated in AML and splicing-related. High levels of some BCL2 family members, in particular BIK and BCL2L13, were associated with poor outcome.

Outcomes of Adult Acute Myeloid Leukemia Treated With Gemtuzumab-Ozogamicin: Cue To Optimized Chemotherapy Backbone

BACKGROUND

The optimal approach to combine gemtuzumab-ozogamicin (GO) with various chemotherapy backbones and other newer agents safely remains to be determined.

MATERIALS AND METHODS

We performed a retrospective analysis of the safety and outcomes of adult patients with newly diagnosed acute myeloid leukemia (AML) treated with GO with intensified versus standard anthracycline doses (daunorubicin dose 90 mg/m² vs 60 mg/m²) ± FLT3 inhibitors. The χ² test and Mann-Whitney U test were used to compare categorical and continuous data. Survival estimates were calculated by Kaplan-Meier method and survival comparisons made using log-rank test.

RESULTS

We report a 97% overall response rate in 34 patients with newly diagnosed AML with a median age of 54 years (19-75 years) treated with GO and standard induction. The 11 patients (100%) receiving GO plus daunorubicin dose 90 mg/m² as part of 7 + 3 induction achieved complete response versus 91% (20/22) complete response in the standard daunorubicin dose group (P = NS). No increased toxicity was noted with the higher daunorubicin dose or when GO and 7 + 3 were combined with FLT3 inhibitors in 3 younger patients (<60 years). Two older patients treated with GO+7 + 3 and FLT3i experienced grade 3 or higher cardiotoxicity. We observed a longer estimated event-free survival for patients with newly diagnosed AML in our cohort (median, 24 months; 95% confidence interval, 17.2 to not reached) compared with historical data.

CONCLUSION

We demonstrate that anthracycline dose intensification with GO may offer higher response rates without increased toxicity in younger patients presenting with de novo AML across European Leukemia Net risk categories.

Mayo Clinic experience with 1123 adults with acute myeloid leukemia

Between 2004 and 2017, a total of 1123 adult patients (median age 65 years; 61% males) with newly diagnosed acute myeloid leukemia (AML), not including acute promyelocytic leukemia, were seen at the Mayo Clinic. Treatment included intensive (n = 766) or lower intensity (n = 144) chemotherapy or supportive care (n = 213), with respective median survivals of 22, 9, and 2 months (p < 0.01). Intensive chemotherapy resulted in complete remission (CR) and CR with incomplete count recovery (CRi) rates of 44 and 33%, respectively, with no difference in survival outcome between the two (p = 0.4). Allogeneic hematopoietic stem cell transplant (AHSCT) was documented in 259 patients and provided the best survival rate (median 55 months; p < 0.01). After a median follow-up of 13 months, 841 (75%) deaths were recorded. Multivariate analysis identified age >60 years (HR 2.2, 1.9-2.6), adverse karyotype (HR 2.9, 1.9-4.9), intermediate-risk karyotype (HR 1.6, 1.02-2.6), post-myeloproliferative neoplasm AML (HR 1.9, 1.5-2.4), and other secondary AML (HR 1.3 (1.1-1.6) as risk factors for shortened survival. These risk factors retained their significance after inclusion of FLT3/NPM1 mutational status in 392 informative cases: FLT3+NPM1- (HR 2.8, 1.4-5.6), FLT3+/NPM+ (HR 2.6 (1.3-5.2), and FLT3-NPM1- (HR 1.8, 1.0-3.0).

Model-Based Optimal AML Consolidation Treatment

OBJECTIVE

Neutropenia is an adverse event commonly arising during intensive chemotherapy of acute myeloid leukemia (AML). It is often associated with infectious complications. Mathematical modeling, simulation, and optimization of the treatment process would be a valuable tool to support clinical decision making, potentially resulting in less severe side effects and deeper remissions. However, until now, there has been no validated mathematical model available to simulate the effect of chemotherapy treatment on white blood cell (WBC) counts and leukemic cells simultaneously.

METHODS

We developed a population pharmacokinetic/pharmacodynamic (PK/PD) model combining a myelosuppression model considering endogenous granulocyte-colony stimulating factor (G-CSF), a PK model for cytarabine (Ara-C), a subcutaneous absorption model for exogenous G-CSF, and a two-compartment model for leukemic blasts. This model was fitted to data of 44 AML patients during consolidation therapy with a novel Ara-C plus G-CSF schedule from a phase II controlled clinical trial. Additionally, we were able to optimize treatment schedules with respect to disease progression, WBC nadirs, and the amount of Ara-C and G-CSF.

RESULTS

The developed PK/PD model provided good prediction accuracies and an interpretation of the interaction between WBCs, G-CSF, and blasts. For 14 patients (those with available bone marrow blast counts), we achieved a median 4.2-fold higher WBC count at nadir, which is the most critical time during consolidation therapy. The simulation results showed that relative bone marrow blast counts remained below the clinically important threshold of 5%, with a median of 60% reduction in Ara-C.

CONCLUSION

These in silico findings demonstrate the benefits of optimized treatment schedules for AML patients.

SIGNIFICANCE

Until 2017, no new drug had been approved for the treatment of AML, fostering the optimal use of currently available drugs.

Hypomethylating Agents Use in Acute Myeloid Leukemia: A Single-Center Experience

Context: Acute myeloid leukemia (AML) is a heterogeneous disease. Approximately 80% of older AML patients will die of their disease or its treatment with currently available antileukemic therapy because of the adverse prognostic risk factors. In elderly patients who are not candidates for induction chemotherapy (IC) or who declines IC, the preferred induction regimen is with hypomethylating agents (HMAs). In India, data regarding therapy with HMA, response to therapy and overall survival (OS) is seldom reported. Aims: This study aims to study the response rate and survival of patients treated with HMAs in whom IC was not feasible. Settings and Design: This is retrospective and descriptive single-center study. Subjects and Methods: Data of newly diagnosed AML patients who were unfit for IC and treated with HMA in our institution was collected retrospectively and analyzed. Results: Twenty-three patients received HMAs as a treatment for AML. Eight (34.7%) of 23 patients had initial response to therapy (two [25%] had complete remission [CR], four [50%] had CR with incomplete hematologic recovery, one [12.5%] had partial remission) and one (12.5%) had stable disease. The median progression-free survival and OS observed are 6.06 ± 0.65 months and 7 ± 1.32 months, respectively. Conclusions: HMAs provide an important additional treatment option in newly diagnosed AML patients who are older, with poor performance status, higher comorbidity indices, and who refuse IC.

Stringent or nonstringent complete remission and prognosis in acute myeloid leukemia: a Danish population-based study

Stringent complete remission (sCR) of acute myeloid leukemia is defined as normal hematopoiesis after therapy. Less sCR, including non-sCR, was introduced as insufficient blood platelet, neutrophil, or erythrocyte recovery. These latter characteristics were defined retrospectively as postremission transfusion dependency and were suggested to be of prognostic value. In the present report, we evaluated the prognostic impact of achieving sCR and non-sCR in the Danish National Acute Leukaemia Registry, including 769 patients registered with classical CR (ie, <5% blasts in the postinduction bone marrow analysis). Individual patients were classified as having sCR (n = 360; 46.8%) or non-sCR (n = 409; 53.2%) based on data from our national laboratory and transfusion databases. Survival analysis revealed that patients achieving sCR had superior overall survival (hazard ratio [HR], 1.34; 95% confidence interval [CI], 1.10-1.64) as well as relapse-free survival (HR, 1.25; 95% CI, 1.03-1.51) compared with those with non-sCR after adjusting for covariates. Cox regression analysis regarding the impact of the stringent criteria for blood cell recovery identified these as significant and independent variables. In conclusion, this real-life register study supports the international criteria for response evaluation on prognosis and, most importantly, documents each of the 3 lineage recovery criteria as contributing independently.

Impact of Blood Count Recovery-based Complete Remission Before Allogeneic Hematopoietic Stem Cell Transplantation on Survival in Patients With Acute Myeloid Leukemia

BACKGROUND

Patients who achieve complete remission (CR) with incomplete blood count recovery (CRi) in acute myeloid leukemia (AML) have inferior overall survival and lower progression-free survival. The aim of this study was to define whether blood count recovery-based CR before allogeneic hematopoietic stem cell transplantation (alloHSCT) had an impact on survival in patients with AML.

MATERIALS AND METHODS

This study has been performed in a retrospective manner. One hundred one patients with AML who received an alloHSCT in our transplant center at Hacettepe University Hospital between the years 2001 and 2018 were evaluated. CRi were defined as bone marrow CR with absolute neutrophil count < 1000/mm³ and/or platelet count < 100.000/mm³. CR and CRi were confirmed just before alloHSCT in bone marrow and peripheral blood, respectively.

RESULTS

A total of 101 patients were entered into the study between 2001 and 2018. Median follow-up for all survivors was 38 months (range, 6-220 months). The 5-year overall survival for patients who were in CRi and patients who were in CR before transplantation were 58% and 67%, respectively (P = .68). The 5-year progression-free survival for patients who were in CRi and patients who were in CR before transplantation were 68% and 64%, respectively (P = .99).

CONCLUSION

In conclusion, we observed equivalent posttransplant outcomes between patients who were in CR and patients who were in CRi before alloHSCT. We assume that alloHSCT eliminated the negative effect of pre-transplant blood count levels.

[Prognostic significance of blood count at the time of achieving morphologic leukemia-free state in adults with acute myeloid leukemia]

Objective: To explore prognostic significance of blood count at the time of achieving first morphologic leukemia-free state[complete remission (CR, ANC ≥1×10(9)/L and PLT ≥100×10(9)/L) , CR with incomplete PLT recovery (CRp) and CR with incomplete ANC and PLT recovery (CRi) ]in adult patients with de novo acute myeloid leukemia (AML) . Methods: From January 2008 to February 2016, data of consecutive newly-diagnosed AML (non-APL) adults who received continuous chemotherapy in our hospital were analyzed retrospectively. Results: 352 patients were included in the study. 179 (50.9%) were male. Median age was 44 (17-65) years. Using the SWOG cytogenetic classification, 87 (24.7%) , 171 (48.6%) , 46 (13.1%) and 48 (13.6%) patients belonged to favorable, intermediate, unfavorable and unknown categories, respectively. 16 (4.5%) had monosomal karyotype and 41 (11.6%) had FLT3-ITD mutation positive. Best response achieved at the time of achieving first morphologic leukemia-free state was CR in 299 (84.9%) patients, CRp in 26 (7.4%) and CRi in 27 (8.1%) . With a median follow-up period of 16 (2-94) months in survivors, the probabilities of cumulative incident of relapse (CIR) rate, disease free survival (DFS) and overall survival (OS) at 30 months were 47.5%, 46.0% and 58.6%, respectively. Multivariate analyses showed that non-CR (CRp or CRi) , was associated with high relapse rate, shorter DFS and OS. In addition, intermediate or high risk of SWOG cytogenetic classification and FLT3-ITD positive were common unfavorable factors affecting CIR, DFS and OS. Peripheral blast ≥60% at diagnosis was adverse factors affecting DFS. Age ≥48 years and bone marrow blasts ≥67% were associated with shorter OS. Conclusion: Blood count at the time of achieving morphologic leukemia-free state was one of the key markers associated with treatment outcomes in adults with AML.

Dielectrophoretic Microfluidic Chip Enables Single-Cell Measurements for Multidrug Resistance in Heterogeneous Acute Myeloid Leukemia Patient Samples

The front-line treatment for adult acute myeloid leukemia (AML) is anthracycline-based combination chemotherapy. However, treatment outcomes remain suboptimal with relapses frequently observed. Among the mechanisms of treatment failure is multidrug resistance (MDR) mediated by the ABCB1, ABCC1, and ABCG2 drug-efflux transporters. Although genetic and phenotypic heterogeneity between leukemic blast cells is a well-recognized phenomenon, there remains minimal data on differences in MDR activity at the individual cell level. Specifically, functional assays that can distinguish the variability in MDR activity between individual leukemic blasts are lacking. Here, we outline a new dielectrophoretic (DEP) chip-based assay. This assay permits measurement of drug accumulation in single cells, termed same-single-cell analysis in the accumulation mode (SASCA-A). Initially, the assay was optimized in pretherapy samples from 20 adults with AML whose leukemic blasts had MDR activity against the anthracyline daunorubicin (DNR) tested using multiple MDR inhibitors. Parameters tested were initial drug accumulation, time to achieve signal saturation, fold-increase of DNR accumulation with MDR inhibition, ease of cell trapping, and ease of maintaining the trapped cells stationary. This enabled categorization into leukemic blast cells with MDR activity (MDR(+)) and leukemic blast cells without MDR activity (MDR(-ve)). Leukemic blasts could also be distinguished from benign white blood cells (notably these also lacked MDR activity). MDR(-ve) blasts were observed to be enriched in samples taken from patients who went on to enter complete remission (CR), whereas MDR(+) blasts were frequently observed in patients who failed to achieve CR following front-line chemotherapy. However, pronounced variability in functional MDR activity between leukemic blasts was observed, with MDR(+) cells not infrequently seen in some patients that went on to achieve CR. Next, we tested MDR activity in two paired AML patient samples. Pretherapy samples taken from patients that achieved CR to front-line chemotherapy were compared with samples taken at time of subsequent relapse. MDR(+) cells were frequently observed in leukemic blast cells in both pretherapy and relapsed samples, consistent with MDR as a mechanism of relapse in these patients. We demonstrate the ability of a new DEP microfluidic chip-based assay to identify heterogeneity in MDR activity in leukemic blasts. The test provides a platform for future studies to characterize the mechanistic basis for heterogeneity in MDR activity at the individual cell level.

Hematologic Recovery after Pretransplant Chemotherapy Does Not Influence Survival after Allogeneic Hematopoietic Cell Transplantation in Acute Myeloid Leukemia Patients

Pretransplant remission status in patients with acute myeloid leukemia (AML) is 1 of the most important factors determining their outcomes after allogeneic hematopoietic cell transplantation (allo-HCT). Most patients are in complete remission with full hematologic recovery (CR) before undergoing allo-HCT. However, some patients achieve CR without recovery of platelet count (CRp) or a morphologic leukemia-free state (MLFS), defined as meeting all CR criteria without recovery of both neutrophil and platelet counts. Currently, there is a paucity of data regarding transplant outcomes in AML patients achieving MLFS after chemotherapy. To address this question, we evaluated transplant outcomes in 270 AML patients who received 6/6 HLA-matched sibling or 10/10 HLA-matched unrelated donor transplantation at a single institution between 2006 and 2013. Of our 270 patients, 206 were in CR, 45 were in CRp, and 19 were in MLFS before allo-HCT. Patients in CR, CRp, or MLFS had similar 3-year overall survival rates (49%, 46%, and 47%, respectively; P = .88) and 3-year event-free survival rates (45%, 36%, and 40%, respectively; P = .53). However, the cumulative incidence of nonrelapse mortality was significantly higher in patients in MLFS compared with those in CR (58% versus 22%, P = .0004), whereas the cumulative incidence of relapse in patients in MLFS was significantly lower compared with those in CR (11% versus 36%, P = .03). Our results suggest that survival outcomes in AML patients are not influenced by degree of hematologic recovery before allo-HCT.

Favorable prognosis of biallelic CEBPA gene mutations in acute myeloid leukemia patients: a meta-analysis

OBJECTIVES

Increasing number of studies suggested that biallelic CEBPA (bi CEBPA) mutations were associated with favorable prognosis in patients with acute myeloid leukemia (AML), but the results remain inconclusive. We therefore present a meta-analysis to evaluate the prognostic value of bi CEBPA mutations in patients with AML.

METHODS

A comprehensive literature search was undertaken through August 2014 looking for eligible studies. Pooled hazard ratios (HRs) estimates and 95% confidence intervals (95% CIs) in overall survival (OS) and event-free survival (EFS) were used to calculate estimated effect.

RESULTS

Ten studies covering a total of 6219 subjects were included in this analysis. Overall, bi CEBPA mutations were associated with favorable clinical outcome in patients with AML (HR for EFS: 0.41, 95% CI: 0.32-0.52; for OS: 0.37, 95% CI: 0.27-0.50), in cytogenetically normal (CN)-AML (HR for EFS: 0.38, 95% CI: 0.29-0.49; for OS: 0.32, 95% CI: 0.23-0.43). When took the cohort of monoallelic CEBPA (mo CEBPA) mutated and wild-type CEBPA (wt CEBPA) AML as a reference group, bi CEBPA mutated AML also shown beneficial outcomes (HR for OS: 0.52, 95% CI: 0.37-0.72). No significant difference was found between mo CEBPA mutation and wt CEBPA in patients with AML or CN-AML (P > 0.05).

CONCLUSION

Bi CEBPA mutations in patients with AML are strongly associated with a favorable prognosis, which suggested that bi CEBPA mutations would potentially serve as a novel prognostic marker in AML.

Methylation pattern of calcitonin (CALCA) gene in pediatric acute leukemia

Disruption of deoxyribonucleic acid (DNA) methylation patterns has emerged as one of the possible origins of leukemogenesis. Calcitonin (CALCA) gene is a hot-spot for gene hypermethylation in acute leukemias. This study aimed to systematically analyze the methylation status of CALCA gene in pediatric acute leukemia using methylation-specific polymerase chain reaction (MSP) and assess its value as a potential prognostic biomarker. The study population consisted of 70 children divided into; 35 acute myeloblastic leukemia (AML) and 35 acute lymphoblastic leukemia (ALL) patients. CALCA gene was found to be hypermethylated in 54.3% of AML and 65.7% of ALL patients. CALCA hypermethylation was neither correlated to any of the clinicopathologic characteristics of patients, standard prognostic factors nor response to induction therapy (P>0.05). Hypermethylated AML and ALL patients displayed poorer clinical outcome when compared with hypomethylated counterparts as evidenced by high relapse and mortality rates with the occurrence of early relapse (P<0.05). The estimated overall and disease-free survival rates at 2.5-years were significantly shorter for hypermethylated patients in both groups (P<0.01). Our results suggest that CALCA gene methylation pattern is an independent prognostic factor in pediatric acute leukemia that could characterize a group of patients with enhanced risk of relapse and death.

AC133 expression in egyptian children with acute leukemia: impact on treatment response and disease outcome

AC133 antigen is expressed restrictively in the immature subset of the CD34 cells. Hence, it is expected to be a valuable prognostic marker in acute leukemia. Sixty Egyptian children with acute leukemia were enrolled into this prospective study divided into 2 groups: 30 acute myeloblastic leukemia (AML) and 30 acute lymphoblastic leukemia (ALL) patients. Flow cytometric assessment of AC133 expression was performed on CD34 blast cells. AC133 was expressed in 66.7% and 40% of AML and ALL patients, respectively. AC133-positive expression was not associated with any of the studied standard prognostic factors. In AML, 80% of patients with poor clinical outcome (relapse or death) were positive for AC133 expression, whereas, all ALL patients who developed resistance as well as those who displayed poor clinical outcome had AC133-positive expression (P<0.05). Patients with positive AC133 expression had significantly shorter overall and disease-free survival times compared with AC133-negative patients in both ALL (P<0.001) and AML (P<0.05) groups. AC133 expression percentage was a reliable poor prognostic marker in ALL patients (P<0.0001). AC133-positive expression is an independent poor prognostic factor in childhood acute leukemia and could characterize a group of patients with resistance to standard chemotherapy, as well as high incidence of relapse and death.

Remission induction, consolidation and novel agents in development for adults with acute myeloid leukaemia

Chemotherapy regimens used for remission induction in AML have not changed significantly over the last several decades. However the recognition of the prognostic value of cytogenetics and genomics has been a major advance which is helping clarify the most optimal post-remission consolidation strategy among various risk groups. We are not only beginning to realize the pitfalls of a 'one-fits-all' approach with intensive, cytarabine-based chemotherapy as the mainstay, but we are finally beginning to reap the rewards of decades of basic, translational, and clinical research. Developing individualized, 'targeted' therapy for each AML patient based on unique molecular features of disease remains a daunting goal yet one that we can now begin to envision. Hypothesis-based study designs-from pre-clinical/laboratory experiments to phase-I and subsequent efficacy trials-provide the foundation for advances in the diagnosis, risk stratification, and treatment for patients with AML. Here we critically review the literature for the management of AML, try to give recommendations regarding the appropriate induction and remission strategy, clarify the role of stem cell transplantation and discuss novel agents on the horizon.

Effect of complete remission and responses less than complete remission on survival in acute myeloid leukemia: a combined Eastern Cooperative Oncology Group, Southwest Oncology Group, and M. D. Anderson Cancer Center Study

PURPOSE

It is known that complete remission (CR) prolongs survival in acute myeloid leukemia (AML). In 2003, less stringent response categories were introduced, most notably CR with incomplete platelet recovery (CRp). Although the significance of CRp for survival remains unclear, reports of AML trials frequently combine CR with CRp rather than considering CR as a separate entity.

PATIENTS AND METHODS

This practice led us to retrospectively examine the effect of CR on outcome in newly diagnosed AML, by using data from 6,283 patients treated on Eastern Cooperative Oncology Group (ECOG) and Southwest Oncology Group (SWOG) protocols or at M. D. Anderson Cancer Center. This effect was then contrasted with the effect of CRp in the M. D. Anderson Cancer Center cohort.

RESULTS

At least 94% of patients receiving cytarabine-based therapy and surviving for more than 3 or 5 years achieved a CR with either initial or salvage therapy; limited data suggest the same for patients receiving initial therapies that did not contain cytarabine. Patients with CR were more likely to live beyond 3 or 5 years than patients with CRp. The likelihood of achieving a CR rather than CRp was greater for patients with AML who had better prognosis. After adjustment for covariates, the relapse-free survival of patients achieving CR was longer than that of patients achieving CRp, whereas patients with CRp survived longer than those with resistant disease.

CONCLUSION

Our data indicate that CR is of unique clinical significance and should be reported as separate response in trials of newly diagnosed AML. Nonetheless, our findings validate CRp as a clinically meaningful response.

What are the endpoints of therapy for acute leukemias? Old definitions and new challenges

Acute leukemias are complex diseases on multiple levels, and laboratory efforts over the past 3 decades have focused on better understanding of the molecular underpinnings and their stem cell biology. We now have a panoply of technologic advances that allow us to characterize individual leukemias by molecular profiles that relate directly to clinical behavior, to detect minimal residual disease, and to begin to develop "targeted" therapeutic strategies based on molecular considerations. There are a number of challenges surrounding this task: first, how to combine these agents with traditional chemotherapeutics and/or with each other to maximize leukemic cell kill and increase the cure rate; second, how to use these targeted agents in the minimal residual disease with potential curative intent; third, for patients unable to tolerate or unlikely to benefit from aggressive approaches, how to use one or more of these agents to reduce tumor bulk and either permit some restoration of normal marrow function or induce morphologic and functional differentiation of the leukemic clone to overcome the leukemia-associated bone marrow failure; and lastly, how to measure the effects of these agents on the molecular and cellular biologic levels in ways that correlate with and might even predict overall clinical outcome. These challenges are further complicated by the inherent heterogeneity in host biology; disease etiology and biology; and interactions among host, disease, and treatment that ultimately determine individual clinical outcomes. Toward this end, we will discuss selected issues surrounding new clinical trial designs and the development of clinically relevant molecular endpoints that might facilitate the development of new treatment approaches that will improve the outlook for adults with acute leukemias.

Tumor associated antigen PRAME is a marker of favorable prognosis in childhood acute myeloid leukemia patients and modifies the expression of S100A4, Hsp 27, p21, IL-8 and IGFBP-2 in vitro and in vivo

Preferentially expressed antigen of melanoma (PRAME) is expressed in a wide variety of tumors, but in contrast with most other tumor associated antigens, it is also expressed in leukemias. In a previous study, we showed that overexpression of PRAME induced apoptosis, inhibited cell proliferation and reduced tumorigenicity of leukemic cells in vivo. We also demonstrated that PRAME overexpression induced the repression of three genes (Hsp27, S100A4 and p21) associated with an unfavorable prognosis in leukemia. Here, we further investigated the mechanisms of PRAME-induced tumor suppression in vitro and in vivo. We performed a gene profiling study by analysing PRAME shRNA-silenced leukemic cells on high-density micro-arrays (Affymetrix) and found that PRAME altered the expression of two additional genes potentially involved in cancerogenesis and cancer progression: IL-8 and IGFBP-2. In a series of 28 acute myeloid leukemia pediatric patients, we observed that PRAME expression was associated with an increased leukemia-free survival. Importantly, the correlation between PRAME expression in leukemic cell lines and the decreased expression of Hsp27, S100A4, p21, IL-8 and the increased expression of IGFBP-2 was also observed in vivo, in leukemic patients. Our results suggest that the favorable prognosis of PRAME could be mediated, at least in part, by the modified expression of those genes.

Diagnostic Problems in Follow-Up Bone Marrow Biopsies of Patients Treated for Acute and Chronic Leukaemias and MDS

Bone marrow biopsy evaluation after therapy for hematolymphoid disorders is complex. The difficulties encountered by the pathologist are due to the fact that a variety of heterogenous diseases for which different treatments can be applied have to be considered. Moreover, usually different clinical questions have to be addressed for which different analyses are performed, typically in different laboratories by different investigators. In the present paper, we suggest a systematic, integrative and interdisciplinary approach that includes knowledge of the original diagnosis and of the type of prior therapy, considers treatment effects and a use of standardized response criteria for AML and MDS. Finally, we discuss how to deal with discrepancies between morphological findings in a bone marrow biopsy and the corresponding aspirate.

Engraftment kinetics and hematopoietic chimerism after reduced-intensity conditioning with fludarabine and treosulfan before allogeneic stem cell transplantation

Reduced-intensity conditioning with fludarabine and treosulfan before allogeneic stem cell transplantation (SCT) was introduced several years ago. Although its feasibility has recently been proven, only limited data are available on myelotoxicity, engraftment kinetics, and the significance of hematopoietic chimerism using this novel conditioning regimen. To clarify these open questions, we analyzed 27 patients with various hematological diseases, who received allogeneic SCT preceded by fludarabine/treosulfan conditioning. Further assessment endpoints included graft-vs-host disease (GvHD), mortality, and overall survival (OS). Allogeneic SCT was followed by neutropenia (absolute neutrophil count < or = 0.5 x 10(9)/l) and thrombocytopenia (platelets < or = 20 x 10(9)/l) in all patients. All patients showed stable neutrophil engraftment, and all except one had stable platelet engraftment. Grades II-IV acute GvHD was found in 48% of patients, whereas 52% developed chronic GvHD. The treatment-related mortality on day +100, 1 year after SCT, and at the last follow-up was 11, 26, and 33%, respectively. We found complete chimerism rates of 46, 57, and 72% on days +28, +56, and at the last follow-up or before death, respectively. The underlying malignancy tended to relapse more frequently in patients with mixed chimerism than in those with complete chimerism on day +28 as well as on day +56 (not significant). Additionally, no significant association was found between hematopoietic chimerism and donor type, GvHD, or OS, respectively. We conclude that reduced-intensity conditioning with fludarabine and treosulfan before allogeneic SCT is myeloablative, provides stable engraftment, and leads to complete chimerism in the majority of patients.

Flow cytometric assessment of autologous gammadelta T cells in patients with acute myeloid leukemia: potential effector cells for immunotherapy?

BACKGROUND

Gammadelta T cells are a rare component of the circulating innate immune system capable of exerting anti-neoplastic activity. This population may be suitable for the adoptive immunotherapy of acute myeloid leukemia (AML). Little is known however, about the frequency and function of circulating gammadelta T cells in AML. The aim of the study was to enumerate peripheral blood gammadelta T cells in patients with AML and explore the feasibility of their use clinically.

METHODS

We compared the absolute circulating gammadelta T cell levels in 33 AML patients before and after treatment versus 20 healthy volunteers using flow cytometry. The function of gammadelta T cells was assessed by detection of intracelluar interferon-gamma (IFN-gamma) and cytotoxicity against leukemic blasts.

RESULTS

AML patients with high blast counts prior to induction chemotherapy had marginally decreased gammadelta T cell levels compared with healthy controls: median 38/microL versus 83/microL; P = 0.051. Sequential gammadelta T cell enumeration after induction showed significantly decreased counts in patients with a persistently high blast burden compared to patients with reduced but detectable residual disease (molecular maker or borderline bone marrow infiltration): median 7/microL versus 105/microL; P = 0.008. Patients with residual disease had significantly higher gammadelta T cell counts compared to those retested after they had achieved complete remission (CR); P = 0.0025. In CR, gammadelta T cell counts remained lower than those of healthy individuals: median 33/microL versus 83/microL, P = 0.030. We detected a sharp increase (on average, four-fold higher than values in CR) of gammadelta T cells in patients in very early morphologic or molecular relapse. We also tested the functional properties of gammadelta T cells from patients with AML in CR. Flow cytometric assessment of IFN-gamma revealed similar numbers of gammadelta T cells expressing the T1 cytokine compared with healthy controls. We also showed that gammadelta T cells were able to kill leukemic target cells in vitro.

CONCLUSION

Flow cytometric assessment of gammadelta T cells in patients with AML revealed quantitative shifts with respect to disease status. Our data suggest that gammadelta T cells warrant further investigation as potential therapeutic agents.

End points to establish the efficacy of new agents in the treatment of acute leukemia

Federal regulations provide 2 pathways for approval of new agents for the treatment of acute leukemia, regular and accelerated approval. Regular approval requires evidence of clinical benefit, which is generally defined as either prolongation of life or improved quality of life, or an effect on an end point established as a surrogate for clinical benefit. Accelerated approval can be obtained based on demonstration of an effect on a surrogate measure "reasonably likely" to predict clinical benefit, but requires demonstration of clinical benefit after approval as well. The acute leukemias are a heterogeneous and relatively uncommon group of diseases. The design and execution of prospective randomized clinical trials demonstrating prolongation of life or improved quality of life for patients with these disorders can be difficult and costly and require lengthy follow-up. Thus, the development of novel trial design and inclusion of validated surrogate markers for clinical benefit are needed. To explore some of the issues pertinent to the choice of end points for drug approval in acute leukemia, the Food and Drug Administration invited the American Society of Hematology to participate in the organization and conduct of a joint workshop. In this report, we present the results of that effort.