Defining Current Patterns of Blood Product Use during Intensive Induction Chemotherapy in Newly Diagnosed Acute Myeloid Leukemia Patients

Introduction

Blood product transfusion retains a critical role in the supportive care of patients with acute myeloid leukemia (AML). Whereas previous studies have shown increased transfusion dependency to portend inferior outcome, predictive factors of an increased transfusion burden and the prognostic impact of transfusion support have not been assessed recently.

Methods/Patients

We performed a retrospective analysis on a recent cohort of patients given intensive induction chemotherapy in 2014-2022.

Results

The analysis comprised 180 patients with a median age of 57 years with 80% designated as de novo AML. Fifty-four patients (31%) were FLT3-ITD mutated, and 73 patients (42%) harbored NPM1. Favorable risk and intermediate risk ELN 2017 patients accounted for 43% and 34% of patients, respectively. The median number of red blood cell (RBC) and platelet units given during induction were 9 and 7 units, respectively. Seventeen patients (9%) received cryoprecipitate, and fresh frozen plasma (FFP) was given to 12 patients (7%). Lower initial hemoglobin and platelet levels were predictive of increased use of RBC (p < 0.0001) and platelet transfusions (p < 0.0001). FFP was significantly associated with induction related mortality (42% vs. 5%; p < 0.0001) and with FLT3-ITD (72% vs. 28%; p = 0.004). Blood group AB experienced improved mean overall survival compared to blood group O patients (4.1 years vs. 2.8 years; p = 0.025). In multivariate analysis, increased number of FFP (hazard ratio [HR], 4.23; 95% confidence interval [CI], 2.1-8.6; p < 0.001) and RBC units (HR, 1.8; 95% CI, 1.2-2.8; p = 0.008) given was associated with inferior survival.

Conclusion

Transfusion needs during induction crucially impact the clinical trajectory of AML patients.

Venetoclax-based salvage therapy for adult patients with relapsed/refractory acute lymphoblastic leukemia

OBJECTIVES

Dysregulation of BCL-2 family members has been reported in acute lymphocytic leukemia (ALL), with various BH3-dependencies of the leukemic clone. We conducted a multicenter retrospective cohort of patients with relapsed/refractory B or T ALL, with ven-chemotherapy or ven-navitoclax combinations, to assess efficacy and safety.

METHODS

Seventeen patients were included in the analysis, median age was 32 years, with 6 B-ALL and 11 T-ALL patients. Nine patients received venetoclax combined with chemotherapy, and 13 patients received venetoclax in combination with navitoclax, vincristine and asparaginase, of which 5 were already exposed to venetoclax in previous lines.

RESULTS

ORR was 55% and 46% among the ven-chemotherapy and the ven-navitoclax-chemotherapy, respectively. Most of the responders proceeded to an allogenic bone marrow transplant in both cohorts. The most common adverse effects of the ven-navitoclax combination were infectious complications and hepatotoxicity.

CONCLUSIONS

Our data demonstrated the possible efficacy of ven-chemotherapy and ven-navitoclax in r/r ALL with moderate toxicity.

The occurrence of thrombosis during intensive chemotherapy treatment for acute myeloid leukemia patients does not impact on long-term survival

Venous thromboembolism (VTE) is frequently seen in acute myeloid leukemia (AML) patients and presents a significant clinical challenge. The association of VTE during intensive chemotherapy with risk models such as the Medical Research Council (MRC) cytogenetic-based assessment and the European LeukemiaNet (ELN) 2017 molecular risk model have not been rigorously evaluated. Additionally, there is a paucity of data pertaining to the long-term prognostic impact of VTE in AML patients. We performed an analysis of baseline parameters of AML patients diagnosed with VTE during intensive chemotherapy and compared them with patients without VTE. The analyzed cohort consisted of 335 newly diagnosed AML patients with a median age of 55 years. Thirty-five patients (11%) were classified as MRC favorable risk, 219 (66%) patients as intermediate risk, 58 patients (17%) as adverse risk. Per ELN 2017, 132 patients (40%) had favorable risk disease, 122 patients (36%) intermediate risk, and 80 patients (24%) had adverse risk. VTE was seen in 33 patients (9.9%), occurring mostly during induction (70%), and required catheter removal in 9 patients (28%). Baseline clinical, laboratory, molecular, and ELN 2017 parameters were not significantly different groups. However, MRC intermediate-risk group patients were significantly more likely to experience thrombosis compared to favorable risk and adverse risk patients (12.8% versus 5.7% and 1.7%, respectively; p = 0.049). Median overall survival was not significantly impacted by the diagnosis of thrombosis (3.7 years versus 2.2 years; p = 0.47). VTE is tightly associated with temporal and cytogenetic parameters in AML but does not significantly impact on long-term outcomes.

Second hematopoietic stem cell transplantation as salvage therapy for relapsed acute myeloid leukemia/ myelodysplastic syndromes after a first transplantation

Second allogeneic hematopoietic stem-cell transplantation (HSCT2) is a therapeutic option for patients with AML/ MDS relapsing after a first transplant (HSCT1). However, patients allocated to HSCT2 may be a selected group with better prognosis and the added efficacy of HSCT2 is not well established. We retrospectively analyzed 407 consecutive patients with relapsed AML/MDS after HSCT1. Sixty-two patients had HSCT2 (15%) and 345 did not. The 2-year cumulative incidence rates of non-relapse mortality and relapse after HSCT2 were 26% (95% CI, 17-39%) and 50% (95% CI, 39-65%), respectively. The 5-year overall survival (OS) rates were 25% (95% CI, 14-36%) and 7% (95% CI, 4-10%) in the HSCT2 and no-HSCT2 groups, respectively. Multivariate-analysis identified female gender (HR 0.31, P=0.001), short remission duration after HSCT1 (HR 2.31, P=0.05), acute GVHD after HSCT1 (HR 2.27, P=0.035), HSCT2 from haplo-identical (HR 13.4, P=0.001) or matched-unrelated donor (HR 4.53, P=0.007) and relapse after HSCT1 in earlier years (HR 2.46, P=0.02) as factors predicting OS after HSCT2. Multivariate-analysis of all patients including HSCT2 entered as time-dependent variable identified relapse within 6 months after HSCT1 (HR 2.32, P<0.001), acute GVHD before relapse (HR 1.47, P=0.005), myeloablative conditioning in HSCT1 (HR 0.67, P=0.011), female gender (HR 0.71, P=0.007), relapse in earlier years (HR 1.33, P=0.031) and not having HSCT2 (HR 1.66, P=0.010) as predictive for OS after relapse. In conclusion, HSCT2 is associated with longer survival compared to non-transplant treatments and may be the preferred approach in a subset of patients with relapsed AML/MDS after HSCT1.

Contemporary evaluation of acute myeloid leukemia patients with long-term survival exceeding five years

OBJECTIVES

Define clinical and laboratory attributes of acute myeloid leukemia (AML) patients with long-term survival exceeding five years and compare them with AML patients succumbing to disease within two years of diagnosis.

METHODS

A retrospective analysis of AML patients alive at least five years from the time of initial diagnosis. Baseline clinical data were compared with patients who died within two years of diagnosis.

RESULTS

The long-term cohort consisted of 93 patients treated in 2007-2016 with a median follow-up duration of 7.7 years (range 5-13.6 years). European LeukemiaNet (ELN) 2017 favorable risk patients accounted for 60% of the cohort. All long-term survivors achieved remission following induction chemotherapy. Multivariate analysis showed that compared with 132 patients experiencing death within 2 years of diagnosis, long term survivors were more likely to be of younger age [odds ratio (OR), 0.92; 95% confidence interval (CI), 0.9-0.95; p<0.001], have a lower initial WBC count (OR, 0.58; 95% CI, 0.43-0.79; p=0.0004), undergo an allogeneic stem cell transplantation (OR, 7.95; 95% CI, 3.07-20.59; p<0.0001), and harbor favorable risk cytogenetics (OR, 0.03; 95% CI, 0.006-0.23; p=0.0004).

CONCLUSIONS

Long term survival of AML is seen in a distinct demographic and biologic patient subset.

Gilteritinib monotherapy for relapsed/refractory FLT3 mutated acute myeloid leukemia: a real-world, multi-center, matched analysis

Patients with FLT3-mutated relapsed or refractory (R/R) acute myeloid leukemia (AML) have a dismal prognosis. Gilteritinib is a FLT3 tyrosine kinase inhibitor (TKI) recently approved for patients with R/R AML. We aimed to characterize real-world data regarding gilteritinib treatment in FLT3-mutated R/R AML and to compare outcomes with matched FLT3-mutated R/R AML patients treated with chemotherapy-based salvage regimens. Twenty-five patients from six academic centers were treated with gilteritinib for FLT3-mutated R/R AML. Eighty percent were treated with a prior intensive induction regimen and 40% of them received prior TKI therapy. Twelve patients (48%) achieved complete response (CR) with gilteritinib. The estimated median overall survival (OS) of the entire cohort was eight (CI 95% 0-16.2) months and was significantly higher in patients who achieved CR compared to those who did not (16.3 months, CI 95% 0-36.2 vs. 2.6 months, CI 95% 1.47-3.7; p value = 0.046). In a multivariate cox regression analysis, achievement of CR was the only predictor for longer OS (HR 0.33 95% CI 0.11-0.97, p = 0.044). Prior TKI exposure did not affect OS but was associated with better event-free survival (HR 0.15 95% CI 0.03-0.71, p = 0.016). An age and ELN-risk matched comparison between patients treated with gilteritinib and intensive salvage revealed similar response rates (50% in both groups); median OS was 9.6 months (CI 95% 2.3-16.8) vs. 7 months (CI 95% 5.1-8.9) in gilteritinib and matched controls, respectively (p = 0.869). In conclusion, in the real-world setting, gilteritinib is effective, including in heavily pre-treated, TKI exposed patients.

Evaluation of the clinical impact of bone marrow cultures in current medical practice

The clinical yield and benefit of performing bone marrow cultures for various clinical indications has been challenged and their clinical necessity remains debatable. We sought to assess the clinical yield and benefit of performing routine bone marrow cultures and determine whether various clinical, laboratory, and imaging parameters were predictive of a diagnostic bone marrow culture. This was a single center retrospective analysis of all patients who underwent a bone marrow study comprising bone marrow cultures from January 1, 2012, through March 1, 2018. Baseline clinical data were extracted from the institution's electronic medical records system. The analyzed cohort consisted of 139 patients with a median age of 46 years (range 4 months to 85 years). The most common indication for a bone marrow study was workup of a fever of unknown origin (105 patients, 76%) while investigation for infection in immunocompromised patients accounted for 22 cases (16%) and suspected tuberculosis was the reason for acquisition of bone marrow cultures in 6 patients (4%). Only 3 patients had positive bone marrow cultures, yielding in 2 patients a diagnosis of Mycobacterium avium and in one patient a microbiologically unclassifiable fungal infection. A univariate analysis revealed that mean age, hemoglobin level, platelet count, c-reactive protein levels, gender, indication for bone marrow study, yield of blood cultures, and contribution of imaging studies and bone marrow pathology results were not significantly different between patients with diagnostic and non-diagnostic bone marrow cultures. Mean white blood cell count was found to be significantly lower in patients with diagnostic bone marrow cultures (2.4 × 10³/µL versus 8.7 × 10³/µL; P = 0.038). We conclude that for most patients, performance of bone marrow cultures holds limited clinical value.

Cytogenetic risk classification maintains its prognostic significance in transplanted FLT3-ITD mutated acute myeloid leukemia patients: On behalf of the acute leukemia working party/European society of blood and marrow transplantation

FMS-like tyrosine kinase 3 internal tandem duplication (FLT3-ITD) mutational status is a pivotal prognosticator in acute myeloid leukemia (AML) patients and significantly increases the risk of disease relapse. However, it remains unclear whether in FLT3-ITD patients referred for allogeneic stem cell transplantation (allo-SCT), baseline cytogenetics significantly impacts clinical outcome. Using the European Society of Blood and Marrow Transplantation registry, we performed a retrospective analysis of 1631 FLT3-ITD AML patients who underwent allo-SCT with the aim of determining the influence of cytogenetic risk category on patient outcomes. Median patient age was 49 years and median follow-up duration was 36 months. Two-year leukemia-free survival (LFS) and incidence of relapse were 54% and 31.6%, respectively. Non-relapse mortality was experienced by 14.4% with a 2-year overall survival (OS) of 60.1%. On multivariate analysis, LFS was significantly lower in patients with intermediate and adverse risk cytogenetics compared with those with favorable risk cytogenetics, (hazard ratio [HR] = 1.48, 95% confidence interval [CI], 1.06-2.06; p = .02), and (HR = 01.65, 95% CI, 1.13-2.40; p = .009), respectively. OS was significantly lower in patients with adverse risk cytogenetics compared with patients with favorable risk cytogenetics (HR = 1.74, 95% CI, 1.16-2.61; p = .008) with a trend toward lower OS in patients with intermediate risk cytogenetics compared to those with favorable risk cytogenetics (HR = 1.43, 95% CI, 1.00-2.05; p = .052). In addition, adverse risk patients and intermediate risk patients experienced higher relapse rates compared with favorable risk patients (HR = 1.83, 95% CI, 1.13-2.94; p = .013 and HR = 1.82, 95% CI, 1.19-2.77; p = .005). Overall, cytogenetic studies aid in refinement of risk stratification in transplanted FLT3-ITD AML patients.

Non-T depleted haploidentical stem cell transplantation in AML patients achieving first complete remission after one versus two induction courses: a study from the ALWP/EBMT

There are no data indicating whether the number of induction courses needed to achieve first complete remission (CR1) is of prognostic significance in Haploidentical transplantation (HaploSCT). We compared transplantation outcomes of adults with AML that underwent HaploSCT in CR1, achieved following one or two induction courses. A total of 635 patients were included: 469 (74%) with 1 and 166 (26%) with two induction chemotherapy courses. A total of 429 (91.5%) and 151 (91%) patients had de novo AML and 40 (8.5%) and 15 (9%) had secondary AML (p = 0.84). Engraftment rates were 97.2 and 97.6%. Day 180 incidence of acute GVHD II-IV and III-IV was similar in both induction groups (31.1 and 34.8%, and 10 and 10.6 %), as was 2-4 year total and extensive chronic GVHD (33.7 and 36.5 %, and 12.2 and 12.1%), respectively. Two-year relapse incidence (RI) was higher while leukemia-free survival (LFS), overall survival (OS) and GVHD-free, relapse-free survival (GRFS) were inferior for patients achieving CR1 with 2 vs 1 course and were 29.1% vs 15.1%, 88 (p = 0.001), 56.2% vs 66.9% (p = 0.03), 58.8% vs 72.2% (p = 0.044) and 44% vs 55.6% (p = 0.013), respectively. Non-relapse mortality (NRM) did not differ, 18% vs 14.6% 90 (p = 0.25). These results were confirmed by multivariate analysis.

Acute Myeloid Leukemia Patients Requiring Two Cycles of Intensive Induction for Attainment of Remission Experience Inferior Survival Compared with Patients Requiring a Single Course of Induction Chemotherapy

BACKGROUND

Achievement of initial remission remains the most important clinical factor predicting long term survival in acute myeloid leukemia (AML) patients treated with intensive chemotherapy. Yet, whether the patient subset in need of a second cycle of intensive induction chemotherapy to reach remission experiences inferior outcomes compared to patients reaching remission after a single cycle of therapy, remains uncertain.

PATIENTS AND METHODS

Retrospective analysis of 302 consecutive AML patients treated with intensive induction chemotherapy in our institution in 2007-2020.

RESULTS

Median patient age was 55 years with a median follow-up duration of 23 months. In terms of European LeukemiaNet (ELN) 2017 classification, 122 patients (40%) were designated as favorable risk disease, 108 patients (36%) were intermediate risk, and 71 patients (24%) were adverse risk. A hundred and seventy-seven patients (60%) attained remission following initial chemotherapy while 58 patients (20%) required an additional cycle of intensive chemotherapy for remission. Patients requiring 2 cycles to reach remission were less likely to be NPM1 mutated (33% versus 51%; P=.025) or be in the ELN 2017 favorable risk category (25% versus 57%; P<.001). In multivariate analysis achievement of remission following 2 cycles of intensive compared with a single cycle resulted in significantly inferior survival [hazard ratio (HR)=1.67, 95% CI, 1.07-2.59; P=.025] whereas leukemia-free survival was not significantly impacted (HR=1.26, 95% CI, 0.85-1.85) (P=.23). Relapse rates also did not differ to a significant degree between groups (45% versus 47%, P=.8).

CONCLUSION

Attainment of an early remission significantly impacts long term survival in AML patients.

Graft-versus-Host Disease Prophylaxis with Post-Transplantation Cyclophosphamide versus Cyclosporine A and Methotrexate in Matched Sibling Donor Transplantation

Cyclosporine A (CSA) and methotrexate (MTX) is the standard graft-versus-host disease (GVHD) prophylaxis regimen for matched sibling donor (MSD) allogeneic hematopoietic cell transplantation (allo-HCT). Recently, post-transplantation cyclophosphamide (PTCy) has been shown to be effective in GVHD prevention. In this registry-based study, we compared outcomes of 118 patients treated with PTCy and 1202 patients with CSA/MTX who underwent MSD allo-HCT for acute myelogenous leukemia. In a matched-pair analysis, PTCy was associated with a higher incidence of relapse at 2 years compared with CSA/MTX (41.1% versus 21.3%; P = .039). The incidences of day +180 grade II-IV acute GVHD and 2-year chronic GVHD were comparable in the PTCy and CSA/MTX arms (25.2% versus 25.4% [P = .90] and 42.6% versus 42.6% [P = .84], respectively). Similarly, 2-year leukemia-free survival (LFS; 54.4% versus 74.32%; P = .052), overall survival (OS; 70.6% versus 79.7%; P = .15), and GVHD-free relapse-free survival (GRFS; 38.1% versus 52.5%; P = .49) were not statistically different in the 2 arms. Our data show that GVHD prophylaxis with PTCy is feasible, resulting in similar incidences of GVHD, GRFS, LFS, and OS as seen with conventional CSA/MTX in patients undergoing allo-HCT from an MSD. The higher rate of relapse observed with PTCy needs further evaluation in a prospective study. © 2021 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc.

Association of Preoperative Clinical, Laboratory, Imaging, and Pathologic Data With Clinically Beneficial Pathology Among Routine Splenectomy Specimens

IMPORTANCE

Previous studies have shown that uniform pathologic review of all splenectomy surgical specimens reveals new clinically actionable diagnoses only in a minority of cases.

OBJECTIVE

To examine whether the aggregate of clinical, laboratory, imaging, and pathologic preoperative data is associated with a clinically beneficial pathologic study for routine splenectomy surgical specimens.

DESIGN, SETTING, AND PARTICIPANTS

This single-center retrospective cohort study included all patients who underwent splenectomy from January 1, 2013, through December 31, 2018, at a single center. Clinical, imaging, and pathologic data were extracted from the institution's electronic medical records system. Data analysis was conducted from June to November 2020.

EXPOSURES

Undergoing splenectomy for trauma or diagnostic or therapeutic indications.

MAIN OUTCOMES AND MEASURES

Spleen pathology study resulting in a new medical diagnosis or change in medical management.

RESULTS

Overall, 90 patients (53 [59%] men) with a median (range) age of 59 (19-90) years underwent splenectomy for therapeutic purposes in 41 patients (45%), trauma in 24 patients (27%), diagnostic purposes in 15 patients (17%), and combined therapeutic and diagnostic purposes in 9 patients (10%). In 14 patients (15%) a new malignant neoplasm was found, and in 8 patients (9%), a new nonneoplastic medical condition was diagnosed. A new pathologic diagnosis resulted in change in medical management in 16 patients (18%). In patients without a prior diagnosis of cancer, 41 of 56 pathology biopsies (73%) were found to be normal whereas in 7 biopsies (13%), a new diagnosis of a hematologic malignant neoplasm was revealed (P < .001). Patients with clinical splenomegaly were significantly more likely to have a new pathologic diagnosis of cancer compared with patients without splenomegaly (15 of 26 [58%] vs 4 of 64 [7%]; P < .001). In 39 of 43 patients (91%) with normal presurgery imaging studies, normal spleen pathology was revealed, whereas in 14 of 17 patients (82%) with abnormal imaging studies, a new hematological malignant neoplasm was diagnosed following pathologic review of the spleen specimen (P < .001). Patients with gross abnormalities on macroscopic examination had a significantly increased likelihood of a hematological cancer diagnosis (17 of 40 [43%]) and a solid cancer diagnosis (4 [10%]) compared with patients with grossly normal specimens (4 of 49 [8%]; P < .001).

CONCLUSIONS AND RELEVANCE

In this cohort study, routine pathologic review of spleen specimens was clinically beneficial in patients with splenomegaly, abnormal imaging results, a prior diagnosis of cancer, and with grossly abnormal spleens.

Venetoclax combinations induce high response rates in newly diagnosed acute myeloid leukemia patients ineligible for intensive chemotherapy in routine practice

Combinations of the BCL-2 inhibitor, venetoclax, with either hypomethylating agents (HMA) or low dose cytarabine (LDAC), have shown promising results in clinical trials of AML patients unfit for intensive therapy. We report on the efficacy and safety of venetoclax combinations in AML patients treated outside of clinical trials. Complete remission (CR) + CR with incomplete count recovery (CRi) were achieved in 61% of patients, with similar CR+CRi rates in with secondary AML, and in patients who were previously treated with HMA (61% and 43%, respectively). Relapse occurred in 25% of patients, with a median event-free survival (EFS) of 11.7 months (95% CI, 10.09-13.35) in responding patients. At a median follow up of 8.7 months, the median overall survival (OS) was 9.8 months (95% CI 6.42-13.3) in the entire cohort. In multivariate analysis adverse karyotype was the only negative predictor of CR/CRi (p = .03), while both ECOG performance status (PS) and adverse karyotype were significantly associated with shorter OS (p = .023 and .038, respectively). Median OS was higher in patients achieving CR/CRi and in patients proceeding to allogeneic stem cell transplantation (allo-SCT). Treatment was well tolerated, with side effects similar to those described in the randomized clinical trials. Tumor lysis syndrome (TLS) occurred in 12% of patients. Our data support the efficacy and safety of venetoclax combinations in newly diagnosed AML patients not eligible for intensive therapy. According to our data, secondary AML patients could benefit from venetoclax combinations similarly to de-novo AML patients, and allo-SCT could be offered to selected patients achieving CR/CRi.

Complete Remission with Incomplete Blood Count Recovery Is a Strong Predictor of Nonrelapse Mortality in Acute Myeloid Leukemia Patients Undergoing Allogeneic Stem Cell Transplantation

INTRODUCTION

Achievement of an initial complete remission (CR) following induction chemotherapy is tightly correlated with survival in acute myeloid leukemia (AML) patients, yet patients in CR with incomplete hematologic recovery (CRi) still experience improved outcomes compared with nonresponding patients. Whether CRi predicts prognosis in patients referred to an allogeneic stem cell transplantation (allo-SCT) is incompletely defined. In this analysis, we evaluated whether clinical outcomes of transplanted AML patients in CR and CRi were significantly different.

METHODS

A retrospective single-center analysis of all de novo AML patients who underwent an allo-SCT between 2001 and 2015. The cohort included all adult patients with AML who underwent a first allo-SCT either in first or second CR or CRi at the time of transplantation.

RESULTS

The study cohort included 186 CR patients and 44 CRi patients. In univariate analysis, CRi was associated with inferior 3-year survival and 3-year nonrelapse mortality (NRM) compared to CR (41 vs. 62%; p = 0.022 and 27 vs. 10%; p = 0.006, respectively). In multivariate analysis, CRi was associated with decreased rates of survival (hazard ratio [HR] 2.01; 95% CI, 1.24-3.25; p = 0.005) and NRM (HR, 3.5; 95% CI, 1.6-7.8; p = 0.002).

CONCLUSION

CRi in transplanted AML patients is potentially a potent predictor of increased NRM and survival.

Outcome of haploidentical versus matched sibling donors in hematopoietic stem cell transplantation for adult patients with acute lymphoblastic leukemia: a study from the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation

Background

Non-T-cell depleted haploidentical hematopoietic stem cell transplantation (HaploSCT) is being increasingly used in acute lymphoblastic leukemia (ALL) with improving patient outcomes. We have recently reported that outcomes of adult patients (pts) with ALL in complete remission (CR) receiving HaploSCT are comparable to unrelated donor transplants. We now compared HaploSCT and matched sibling donor (MSD) transplants in pts with ALL.

Aim

To assess transplantation outcomes of HaploSCT and MSD transplants in pts with ALL in CR.

Methods

We retrospectively analyzed adult patients (≥ 18 years) with ALL who underwent their first allogeneic stem cell transplantation (alloSCT) in first or second CR between 2012 and 2018, either from a T cell replete Haplo or MSD donor, and whose data were reported to the Acute Leukemia Working Party (ALWP) of the European Society for Blood and Marrow Transplantation (EBMT). Multivariate analysis (MVA) adjusting for differences between the groups was performed using the Cox proportional hazards regression model. Propensity score matching was also performed to reduce confounding effects.

Results

The analysis comprised 2304 patients: HaploSCT-413; MSD-1891. Median follow-up was 25 months. Median age was 37 (range 18–75) and 38 (18–76) years in HaploSCT and MSD, respectively. HaploSCT patients were transplanted more recently than those transplanted from MSD (2016 vs 2015, p < 0.0001). A higher rate of HaploSCT was in CR2 (33.4% vs 16.7%, p < 0.0001), respectively, and fewer received myeloablative conditioning (68% vs 83.2%, p < 0.0001). Cytomegalovirus (CMV) seropositivity was lower in HaploSCT patients (22% vs 28%, p = 0.01) and donors (27.1% vs 33%, p < 0.02), and a higher proportion of the HaploSCTs were performed using a bone marrow (BM) graft (46.2% vs 18.6%, p < 0.0001). The 2 groups did not differ with regard to gender, Karnofsky performance status score, ALL phenotype, Philadelphia chromosome (Ph) positivity and pre-alloSCT measurable residual disease (MRD). Graft versus host disease (GVHD) prophylaxis was mainly post-transplant cyclophosphamide (PTCy) based (92.7%) in the HaploSCT setting, while it was mostly pharmacologic in the setting of MSD (18.7% received ATG). Cumulative incidence of engraftment at day 60 was higher in MSD transplants compared to HaploSCT (98.7% vs 96.3%, p = 0.001), respectively. Day 180 incidence of acute (a) GVHD II-IV and III-IV was higher in HaploSCT vs. MSD: 36.3% vs 28.9% (p = 0.002 and 15.2% vs 10.5% (p = 0.005), respectively. Conversely, the 2-year chronic (c) GVHD and extensive cGVHD were 32% vs 38.8% (p = 0.009) and 11.9% vs 19.5% (p = 0.001) in HaploSCT vs MSD, respectively. Main causes of death were leukemia (31.8% vs 45%), infection (33.1% vs 19.7%) and GVHD (16.6% vs 19.7%) for HaploSCT and MSD, respectively. Two-year relapse incidence (RI), non-relapse mortality (NRM), leukemia-free survival (LFS), overall survival (OS) and GVHD-free, relapse-free survival (GRFS) were 26% vs 31.6%, 22.9% vs 13%, 51% vs 55.4%, 58.8% vs 67.4% and 40.6% vs 39% for HaploSCT and MSD, respectively. In the MVA, RI was significantly lower in HaploSCT in comparison with MSD, hazard ratio (HR) = 0.66 (95% CI 0.52–0.83, p = 0.004), while NRM was significantly higher, HR = 1.9 (95% CI 1.43–2.53, p < 0.0001). aGVHD grade II-IV and grade III-IV were higher in HaploSCT than in MSD HR = 1.53 (95% CI 1.23–1.9, p = 0.0002) and HR = 1.54 (95% CI 1.1–2.15, p = 0.011), respectively. Extensive cGVHD was lower in HaploSCT compared with MSD, HR = 0.61 (95% CI 0.43–0.88, p = 0.007), while total cGVHD did not differ significantly, HR = 0.94 (95% CI 0.74–1.18, p = 0.58). LFS, OS and GRFS did not differ significantly between the 2 transplant groups, HR = 0.96 (95% CI 0.81–1.14, p = 0.66); HR = 1.18 (95% CI 0.96–1.43, p = 0.11) and HR = 0.93 (95% CI 0.79–1.09, p = 0.37), respectively. These results were confirmed in a matched-pair analysis.

Conclusions

Outcomes of adult patients with ALL in CR receiving alloSCT from haploidentical donors are not significantly different from those receiving transplants from MSD in terms of LFS, OS and GRFS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13045-021-01065-7.

Outcome of T-cell-replete haploidentical stem cell transplantation improves with time in adults with acute lymphoblastic leukemia: A study from the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation

BACKGROUND

The use of haploidentical hematopoietic cell transplantation (haplo-HCT) with posttransplantation cyclophosphamide prophylaxis is gaining traction in patients with acute lymphoblastic leukemia (ALL).

METHODS

The Acute Leukemia Working Party/European Society for Blood and Marrow Transplantation registry was used to evaluate the outcomes of adult patients with ALL who underwent haplo-HCT during 2011 through 2015 and compared them with the outcomes of those who underwent transplantation during 2016 through 2018.

RESULTS

The analysis consisted of 195 patients, including 79 who underwent transplantation during 2011 through 2015 and 116 who underwent transplantation during 2016 through 2018. Overall, the 2-year leukemia-free survival and relapse incidence rates were 56.5% and 21%, respectively. The 100-day incidence of grade 2 through 4 acute graft-vs-host disease (GVHD) was 34.5%. The rates of nonrelapse mortality (NRM) and overall survival (OS) were 22.5% and 64.7%, respectively. Patients who underwent transplantation during 2016 through 2018 experienced improved rates of leukemia-free survival (64.9% vs 47.3%; P = .019) and OS (75.5% vs 53.5%; P = .006). Patients who underwent transplantation during 2016 through 2018 developed more grade 2 through 4 acute GVHD (42% vs 26.4%; P = .047). The incidence of relapse, GVHD-free/relapse-free survival, grade 3 and 4 acute GVHD, chronic GVHD, and extensive chronic GVHD did not differ significantly between groups. In multivariate analysis, more recently transplanted patients had a significantly reduced risk of NRM (hazard ratio, 0.44; 95% CI, 0.22-0.89; P = .022) and improved OS (hazard ratio, 0.47; 95% CI, 0.26-0.86; P = .014). A comparable analysis of patients who had acute myeloid leukemia during the same timeframes did not reveal any statistically significant differences in any outcomes.

CONCLUSIONS

The outcome of adult patients with ALL who receive posttransplant cyclophosphamide has improved over time, with an impressive 2-year OS of 75% and, most recently, an NRM rate of only 17%.

A phase II study of bisantrene in patients with relapsed/refractory acute myeloid leukemia

OBJECTIVES

To determine the current role of bisantrene, an anthracene with anthracycline-like activity which was shown in earlier studies to be effective therapy in relapsed/refractory acute myeloid leukemia with no discernible cardiotoxicity, in the treatment of patients with R/R AML.

METHODS

This phase 2, single-center study (NCT03820908) enrolled adult R/R AML to receive bisantrene (250 mg/m² daily for 7 days) which was administered via an intravenous infusion over 2 hours on days 1-7. Disease assessment included routine blood work and bone marrow studies.

RESULTS

In all, 10 patients were enrolled with a median of 3 lines of prior therapy including seven patients who had relapsed following allogeneic stem cell transplantation. The most frequently reported grade ≥3 treatment-attributed hematologic AE was thrombocytopenia, whereas the most frequently reported grade ≥3 treatment-attributed non-hematologic AE was mucositis. Of the 10 patients, one (10%) achieved a complete remission and three patients achieved a partial remission resulting in an overall response rate of 40%. Next-generation sequencing of patient samples identified a wide array of mutations associated with activated signaling, splicing, and epigenetic modification.

CONCLUSIONS

In view of the observed low toxicity, a follow-up study combining bisantrene with complementary anti-leukemic therapy is planned.

Comparison of Haploidentical Bone Marrow versus Matched Unrelated Donor Peripheral Blood Stem Cell Transplantation with Posttransplant Cyclophosphamide in Patients with Acute Leukemia

PURPOSE

Posttransplant cyclophosphamide (PTCy) is increasingly being utilized as a principle GvHD prophylaxis strategy in allogeneic hematopoietic cell transplantation (allo-HCT). A haploidentical (haplo) or matched unrelated donor (UD) is a valid option in the absence of a matched related donor.

EXPERIMENTAL DESIGN

We compared the outcomes of patients with acute leukemia who underwent haplo bone marrow (haplo-BM, N = 401) versus UD mobilized peripheral blood stem cells (UD-PB, N = 192) transplantation in the setting of PTCy.

RESULTS

The median follow-up duration was 36 months in the haplo-BM group and 16.6 months in the UD-PB group, respectively (P < 0.01). Myeloablative conditioning was used in 64.6% and 42.7% of haplo-BM and UD-PB patients, respectively (P < 0.01). Cumulative incidence of neutrophil engraftment at day 30 was 87% in haplo-BM versus 94% in UD-PB, respectively (P = 0.21). In the multivariate analysis, the risk of grade 2-4 acute GvHD (HR = 0.53, P = 0.01) and chronic GvHD (HR = 0.50, P = 0.02) was significantly lower in the haplo-BM group compared with the UD-PB group. There was no significant difference between the study groups with respect to relapse incidence, nonrelapse mortality, leukemia-fee survival, overall survival, or GvHD-free and relapse-free survival.

CONCLUSIONS

The use of a haplo donor with a BM graft resulted in a lower incidence of GvHD compared with a UD-PB stem cell graft in the setting of PTCy for patients with acute leukemia. However, differences in GvHD did not translate into a difference in survival outcomes. Based upon these data, UD-PB or haplo-BM should be considered equally acceptable sources for allo-HCT.

Cytogenetic risk score maintains its prognostic significance in AML patients with detectable measurable residual disease undergoing transplantation in remission: On behalf of the acute leukemia working party of the European society for blood and marrow transplantation

While evidence for measurable residual disease (MRD) is a harbinger of inferior outcome in acute myeloid leukemia (AML) patients referred for allogeneic stem cell transplantation (allo-SCT), the exact clinical trajectory of specific patient subsets in this clinical setting is undefined. Using a recently published prognostic cytogenetic model (Canaani et al. Leukemia 2019) we evaluated whether this model applied also to studies of patients with positive MRD. The analysis comprised MRD+ patients in first complete remission undergoing allo-SCT from a matched sibling donor or unrelated donor. Seven hundred and seventy-five patients were evaluated with a median follow-up duration of 22 months. Cytogenetic risk score was favorable, intermediate/FLT3wt intermediate/FLT3-ITD3, and adverse in 15%, 28.3%, 37% and 19.7% of the patients, respectively. Favorable and intermediate/FLT3wt risk patients had 2-year leukemia-free survival rates of 78% and 61%, respectively, compared with only 50% and 37% for intermediate/FLT3-ITD3 and adverse risk patients, respectively (P < .001). In multivariate analysis adverse and intermediate/FLT3-ITD3 risk patients were more likely to experience disease relapse compared with favorable risk patients [hazard ratio (HR) = 3.9, 95% confidence interval (CI), 2.1-7.3; P < .001, and HR = 4.4, CI 95%, 2.4-7.8; P < .001, respectively]. The European society for blood and marrow transplantation cytogenetic risk score is a valuable adjunct for risk stratification of MRD+ AML patients.

Reassessing the role of high dose cytarabine and mitoxantrone in relapsed/refractory acute myeloid leukemia

A substantial segment of patients with acute myeloid leukemia (AML) will relapse following an initial response to induction therapy or will prove to be primary refractory. High-dose cytarabine and mitoxantrone (HiDAC/MITO) is an established salvage therapy for these patients. We studied all adult patients with relapsed/refractory (R/R) AML who were treated with HiDAC/MITO in our center between the years 2008-2017. To determine whether responding patients harbored a unique molecular signature, we performed targeted next-generation sequencing (NGS) on a subset of patients. The study cohort consisted of 172 patients with a median age of 54 years (range 18–77). The composite complete remission rate was 58%; 11 patients (6%) died during salvage therapy. Median survival was 11.4 months with a 1-year survival rate of 48%. In multivariate analysis favorable risk cytogenetics [Odds ratio (OR)=0.34, confidence interval (CI) 95%, 0.17–0.68; P = 0.002], and de-novo AML (OR = 0.4, CI 95%, 0.16–0.98; P = 0.047) were independently associated with a favorable response. Patients who attained a complete remission had a median survival of 43.7 months compared with 5.2 months for refractory patients (p < 0.0001). Neither the FLT3-ITD and NPM1 mutational status nor the indication for salvage therapy significantly impacted on the response to HiDAC/MITO salvage. NGS analysis identified 20 different mutations across the myeloid gene spectrum with a distinct TP53 signature detected in non-responding patients. HiDAC/MITO is an effective salvage regimen in R/R AML, however patients with adverse cytogenetics or secondary disease may not benefit as much from this approach.

Emerging Therapies for the Myelodysplastic Syndromes

Despite considerable advances in our understanding of the molecular and epigenetic underpinnings of the myelodysplastic syndromes (MDS), this diverse group of myeloid neoplasms remains a significant clinical challenge. Considerable barriers to timely development of effective therapy include the diverse molecular landscape encountered in MDS patients, the difficulty in translating specific molecular aberration into a clinically meaningful animal model, as well as challenges in patient recruitment into clinical trials. These speak to the need to discover efficacious novel therapeutic targets which would in turn translate into improved patient outcomes in terms of both survival and quality of life. In this review, we outline recently published data pertaining to therapeutic advances in TGF-β pathway inhibition, STAT3, Hedgehog signaling, and additional therapeutic venues being actively explored in MDS.

Two-dimensional speckle-tracking strain detects subclinical cardiotoxicity in older patients treated for acute myeloid leukemia

BACKGROUND

Patients with acute myeloid leukemia (AML) are surviving longer. There are no data on changes in myocardial mechanics from standard of care low-dose anthracycline-based induction chemotherapy in older patients with AML. The aim of this study was to demonstrate the potential utility of strain imaging in detecting early changes in left ventricular function in this patient population after induction chemotherapy.

METHODS

Thirty two patients enrolled in the ECOG-ACRIN E2906 study (cytarabine and daunorubicin vs clofarabine [Genzyme/Sanofi]) from 2011 to 2014 were evaluated retrospectively. Two-dimensional transthoracic echocardiography (TTE) imaging with Doppler and two-dimensional speckle-tracking echocardiography (2DSTE) using EchoInsight software (Epsilon imaging) were performed before and after induction chemotherapy.

RESULTS

Eighteen patients received cytarabine and daunorubicin (7 + 3) and 14 received clofarabine. The clofarabine group was older than the 7 + 3 cohort (67.8 ± 4.0 vs 63.7 ± 3.8, P = .007). There were no other significant differences in cardiac risk factors between groups. The 7 + 3 group had a decrease in average peak systolic global longitudinal (-19.1 ± 2.8 to -17.2 ± 3.0, P = .01) and circumferential strain (-29.4 ± 6.3 to -23.9 ± 4.3, P = .011). These changes were not demonstrated in the clofarabine group and were not associated with a decline in left ventricular ejection fraction (LVEF).

CONCLUSIONS

In older AML patients, standard cytarabine and daunorubicin chemotherapy causes early changes in global longitudinal and circumferential strain not seen with clofarabine therapy. These findings demonstrate subclinical left ventricular dysfunction after exposure to low cumulative doses of anthracycline-based induction chemotherapy and may help us better identify those patients at risk for adverse long-term cardiovascular outcomes.

The mTOR inhibitor everolimus overcomes CXCR4-mediated resistance to histone deacetylase inhibitor panobinostat through inhibition of p21 and mitotic regulators

Although having promising anti-myeloma properties, the pan-histone deacetylase inhibitor (HDACi) panobinostat lacks therapeutic activity as a single agent. The aim of the current study was to elucidate the mechanisms underlying multiple myeloma (MM) resistance to panobinostat monotherapy and to define strategies to overcome it. Sensitivity of MM cell lines and primary CD138+ cells from MM patients to panobinostat correlated with reduced expression of the chemokine receptor CXCR4, whereas overexpression of CXCR4 in MM cell lines increased their resistance to panobinostat. Decreased sensitivity to HDACi was associated with reversible G0/G1 cell growth arrest while response was characterized by apoptotic cell death. Analysis of intra-cellular signaling mediators revealed the pro-survival mTOR pathway to be regulated by CXCR4 overexpression. Combining panobinostat with mTOR inhibitor everolimus abrogated the resistance to HDACi and induced synergistic cell death. The combination of panobinostat/everolimus resulted in sustained DNA damage and irreversible suppression of proliferation accompanied by robust apoptosis. Gene expression analysis revealed distinct genetic profiles of single versus combined agent exposure. Whereas panobinostat increased the expression of the cell cycle inhibitor p21, co-treatment with everolimus abrogated the increase in p21 and synergistically downregulated the expression of DNA repair genes and mitotic checkpoint regulators. Importantly, the combination of panobinostat with everolimus effectively targeted CXCR4-expressing resistant MM cells in vivo in the BM niche. In summary, our results uncover the mechanism responsible for the strong synergistic anti-MM activity of dual HDAC and mTOR inhibition and provide the rationale for a novel potential therapeutic approach to treat MM.

Clonal Selection with RAS Pathway Activation Mediates Secondary Clinical Resistance to Selective FLT3 Inhibition in Acute Myeloid Leukemia

Gilteritinib is a potent and selective FLT3 kinase inhibitor with single-agent clinical efficacy in relapsed/refractory FLT3-mutated acute myeloid leukemia (AML). In this context, however, gilteritinib is not curative, and response duration is limited by the development of secondary resistance. To evaluate resistance mechanisms, we analyzed baseline and progression samples from patients treated on clinical trials of gilteritinib. Targeted next-generation sequencing at the time of AML progression on gilteritinib identified treatment-emergent mutations that activate RAS/MAPK pathway signaling, most commonly in NRAS or KRAS. Less frequently, secondary FLT3-F691L gatekeeper mutations or BCR-ABL1 fusions were identified at progression. Single-cell targeted DNA sequencing revealed diverse patterns of clonal selection and evolution in response to FLT3 inhibition, including the emergence of RAS mutations in FLT3-mutated subclones, the expansion of alternative wild-type FLT3 subclones, or both patterns simultaneously. These data illustrate dynamic and complex changes in clonal architecture underlying response and resistance to mutation-selective tyrosine kinase inhibitor therapy in AML. SIGNIFICANCE: Comprehensive serial genotyping of AML specimens from patients treated with the selective FLT3 inhibitor gilteritinib demonstrates that complex, heterogeneous patterns of clonal selection and evolution mediate clinical resistance to tyrosine kinase inhibition in FLT3-mutated AML. Our data support the development of combinatorial targeted therapeutic approaches for advanced AML.See related commentary by Wei and Roberts, p. 998.This article is highlighted in the In This Issue feature, p. 983.

Trends in patient outcome over the past two decades following allogeneic stem cell transplantation for acute myeloid leukaemia: an ALWP/EBMT analysis

BACKGROUND

Outcomes for patients with acute myeloid leukaemia (AML) undergoing allogeneic stem cell transplantation (allo-SCT) have significantly improved in recent years.

OBJECTIVES

To assess the incremental improvement of transplanted AML patients in the last two decades.

METHODS

Patients included in this analysis were adult AML patients who underwent allo-SCT from an HLA-matched sibling donor (MSD) or HLA-matched unrelated donor (MUD) in first remission. Patient outcomes were assessed between three cohorts according to the year of transplant (1993-2002, 2003-2007 and 2008-2012).

RESULTS

The analysis comprised a total of 20 187 patients of whom 4763 were transplanted between 1993 and 2002, 5835 in 2003 and 2007, and 9589 in 2008 and 2012. In multivariate analysis, leukaemia-free survival (LFS) rates were significantly improved in more recently transplanted patients compared to patients transplanted in 1993-2002 [Hazard ratio (HR) = 0.84, confidence interval (CI) 95%, 0.77-0.92; P = 0.003], a benefit which also extended to improved overall survival (OS; HR = 0.8, CI 95%, 0.73-0.89; P < 0.0001), and decreased nonrelapse mortality (NRM) rates (HR = 0.65, CI 95%, 0.56-0.75; P < 0.0001). Subset analysis revealed that in MSD, the rates of LFS, NRM and OS significantly improved in patients in the more recent cohort with similar results also seen in MUD. Finally, the incidence of acute graft-versus-host disease (GVHD) was significantly reduced leading to improved GVHD-free/relapse-free survival (GRFS) rates in more recently transplanted patients.

CONCLUSION

Outcome of allo-SCT for AML patients has markedly improved in the last two decades owing to decreased nonrelapse mortality and improved rates of leukaemia-free survival resulting in significantly longer survival.

Management of AML Beyond "3 + 7" in 2019

The therapeutic paradigm for treatment of acute myeloid leukemia (AML) is rapidly changing with the advent of a new generation of drugs targeting diverse aspects of leukemogenesis. Whereas standard treatment for AML until recently consisted of a classic chemotherapy backbone, the incorporation of novel agents targeting pathogenic mutations, myeloid surface markers, and apoptosis-related proteins may become a reality in the next few years. In this review, we outline the therapeutic landscape of recently approved novel agents for AML, including FLT3 inhibitors, isocitrate dehydrogenase 1/2 (IDH1/2) inhibitors, Bcl-2 antagonists, hedgehog signaling inhibitors, and immunotherapy-based approaches. Some of the future challenges in the field would be to delineate which specific patient subsets derive the most clinical benefit from a given novel agent and, furthermore, which drug combinations will yield the maximal antileukemia effect without increased toxicity. To this end, it is expected that advances in genomic and epigenomic classification of AML will facilitate a rational and optimal choice of these novel agents for AML patients.

A novel method for detecting the cellular stemness state in normal and leukemic human hematopoietic cells can predict disease outcome and drug sensitivity

Acute leukemia is an aggressive blood malignancy with low survival rates. A high expression of stem-like programs in leukemias predicts poor prognosis and is assumed to act in an aberrant fashion in the phenotypically heterogeneous leukemia stem cell (LSC) population. A lack of suitable genome engineering tools that can isolate LSCs based on their stemness precludes their comprehensive examination and full characterization. We hypothesized that tagging endogenous stemness-regulatory regions could generate a genome reporter for the putative leukemia stemness-state. Our analysis revealed that the ERG  + 85 enhancer region can serve as a marker for stemness-state and a fluorescent lentiviral reporter was developed that can accurately recapitulate the endogenous activity. Using our novel reporter, we revealed cellular heterogeneity in several leukemia cell lines and patient-derived samples. Alterations in reporter activity were associated with transcriptomic and functional changes that were closely related to the hematopoietic stem cell (HSC) identity. Notably, the differentiation potential was skewed towards the erythro-megakaryocytic lineage. Moreover, an ERG  + 85^High fraction of AML cells could regenerate the original cellular heterogeneity and was enriched for LSCs. RNA-seq analysis coupled with in silico drug-screen analysis identified 4HPR as an effective inhibitor of ERG  + 85^High leukemia growth. We propose that further utilization of our novel molecular tool will identify crucial determinants of LSCs, thus providing a rationale for their therapeutic targeting.

Identification of strong intron enhancer in the heparanase gene: effect of functional rs4693608 variant on HPSE enhancer activity in hematological and solid malignancies

Heparanase is an endo-β-glucuronidase that specifically cleaves the saccharide chains of heparan sulfate (HS) proteoglycans and releases HS-bound cytokines, chemokines, and bioactive growth-promoting factors. Heparanase plays an important role in the nucleus as part of an active chromatin complex. Our previous studies revealed that rs4693608 correlates with heparanase levels and increased risk of acute and extensive chronic graft vs. host disease (GVHD). Discrepancy between recipient and donor in this SNP significantly affected the risk of acute GVHD. In the present study, we analyzed the HPSE gene region, including rs4693608, and demonstrated that this region exhibits SNPs-dependent enhancer activity. Analysis of nuclear proteins from normal leukocytes revealed their binding to DNA probe of both alleles with higher affinity to allele G. All malignant cell lines and leukemia samples disclosed a shift of the main bands in comparison to normal leukocytes. At least five additional shifted bands were bound to allele A while allele G probe was bound to only one main DNA/protein complex. Additional SNPs rs4693083, rs4693084, and rs4693609 were found in strong linkage disequilibrium (LD) with rs11099592 (exon 7). Only rs4693084 affected protein binding to DNA in cell lines and leukemia samples. As a result of the short distance between rs4693608 and rs4693084, both SNPs may be included in a common DNA/protein complex. DNA pull-down assay revealed that heparanase is involved in self-regulation by negative feedback in rs4693608-dependent manner. During carcinogenesis, heparanase self-regulation is discontinued and the helicase-like transcription factor begins to regulate this enhancer region. Altogether, our study elucidates conceivable mechanism(s) by which rs4693608 SNP regulates HPSE gene expression and the associated disease outcome.

T-cell replete haploidentical stem cell transplantation attenuates the prognostic impact of FLT3-ITD in acute myeloid leukemia: A report from the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation

Acute myeloid leukemia (AML) patients harboring the FLT3-ITD mutation are considered a high risk patient subset preferentially allocated for allogeneic stem cell transplantation in first remission. Whether FLT3-ITD retains a prognostic role in haploidentical stem cell transplantation (haplo-SCT) is unknown. To analyze the prognostic impact of FLT3-ITD in haplo-SCT, we performed a retrospective analysis of the multicenter registry of the acute leukemia working party of the European Society for Blood and Marrow Transplantation. We included all adult AML patients with known FLT3 status who underwent a first T-cell replete related haplo-HCT in first complete remission from 2005 to 2016. We evaluated 293 patients of whom 202 were FLT3^wt and 91 were FLT3-ITD mutated. FLT3-ITD patients were more likely to be NPM1 mutated as well as be in the intermediate risk cytogenetic risk category. In multivariate analysis, patients with FLT3-ITD had comparable rates of relapse incidence [Hazard ratio (HR) = 1.34, confidence interval (CI) 95%, 0.67-2.7; P = .9] and leukemia-free survival (HR = 0.99, CI 95%, 0.62-1.57; P = .9) to those of FLT3^wt patients. Overall survival, the incidence of nonrelapse mortality, and graft versus host disease-free/relapse-free survival were not significantly impacted by FLT3-ITD status. Furthermore, relapse and overall survival were comparable between FLT3-ITD patients transplanted from various donor pools, namely matched siblings, unrelated donors, haplo-SCT). Finally, subset analysis of patients with intermediate risk cytogenetics confirmed the absence of a prognostic impact of FLT3-ITD also for this patient segment. In AML patients undergoing T-cell replete haplo-SCT, the FLT3-ITD mutation possibly does not retain its prognostic significance.

Comparable results of autologous and allogeneic haematopoietic stem cell transplantation for adults with Philadelphia-positive acute lymphoblastic leukaemia in first complete molecular remission: An analysis by the Acute Leukemia Working Party of the EBMT

BACKGROUND

Allogeneic haematopoietic stem cell transplantation (alloHSCT) is considered a standard treatment for patients with Philadelphia chromosome-positive acute lymphoblastic leukaemia (Ph+ ALL) achieving complete remission after induction containing tyrosine kinase inhibitors (TKIs).

METHODS

We retrospectively compared results of myeloablative alloHSCT from either matched sibling donor (MSD) or unrelated donor (URD) with autologous (auto) HSCT for adults with Ph+ ALL in molecular remission, treated between 2007 and 2014.

RESULTS

In univariate analysis, the incidence of relapse at 2 years was 47% after autoHSCT, 28% after MSD-HSCT and 19% after URD-HSCT (P = 0.0002). Respective rates of non-relapse mortality were 2%, 18%, and 22% (P = 0.001). The probabilities of leukaemia-free survival were 52%, 55% and 60% (P = 0.69), while overall survival rates were 70%, 70% and 69% (P = 0.58), respectively. In multivariate analysis, there was a trend towards increased risk of overall mortality after MSD-HSCT (hazard ratio [HR], 1.5, P = 0.12) and URD-HSCT (HR, 1.6, P = 0.08) when referred to autoHSCT. The use of total body irradiation (TBI)-based regimens was associated with reduced risk of relapse (HR, 0.65, P = 0.02) and overall mortality (HR, 0.67, P = 0.01).

CONCLUSION

In the era of TKIs, outcomes of myeloablative autoHSCT and alloHSCT for patients with Ph+ ALL in first molecular remission are comparable. Therefore, autoHSCT appears to be an attractive treatment option potentially allowing for circumvention of alloHSCT sequelae. Irrespective of the type of donor, TBI-based regimens should be considered the preferable type of conditioning for Ph+ ALL.

Donor age determines outcome in acute leukemia patients over 40 undergoing haploidentical hematopoietic cell transplantation

Haploidentical hematopoietic cell transplantation (haplo-HCT) is being increasingly used in acute leukemia patients as an alternative transplant modality when matched sibling or matched unrelated donors are unavailable. As several potential haploidentical relative donors are typically available for a given patient, optimizing donor selection to improve clinical outcome is crucial. The impact of donor age and kinship on the outcome of acute leukemia patients is not clearly established in this setting. Using the multinational registry of the acute leukemia working party of the European society for blood and marrow transplantation we retrospective analyzed the clinical outcome of 1270 acute myeloid leukemia and acute lymphoblastic leukemia patients who underwent haplo-HCT between 2005 and 2015. Patients over the age of 40 were significantly affected by increasing donor age resulting in higher non-relapse mortality (NRM) [Hazard ratio (HR)=1.86, confidence interval (CI) 95%, 1.18-2.94; P = .007], inferior leukemia-free survival (LFS) (HR = 1.59, CI 95%, 1.13-2.24; P = .007), and overall survival (OS) (HR = 1.74, CI 95%, 1.22-2.47; P = .002) when donors were over the age of 40. Additionally, kinship was found to be prognostically significant as patients transplanted from children donors over the age of 35 experienced an increased rate of NRM (HR = 1.82, CI 95%, 1.13-2.9; P = .01), inferior LFS (HR = 1.5, CI 95%, 1.05-2.13; P = .03), and OS (HR = 1.5, CI 95%, 1.04-2.15; P = .03). For patients younger than 40 years, donor age and kinship were mostly not clinically impactful. Our data establish donor age and kinship as significant determinants of outcome following haplo-HCT for acute leukemia patients.

Allogeneic stem cell transplantation in acute lymphoblastic leukemia patients older than 60 years: a survey from the acute leukemia working party of EBMT

Hematopoietic stem cell transplantation (HSCT) is being increasingly explored as a treatment modality for older patients with acute lymphoblastic leukemia (ALL). Yet, concerns regarding the long term outcome of transplantation in older patients limit the wide spread applicability of this approach. In this analysis we set out to determine the outcome of ALL patients over the age of 60 who underwent reduced intensity HSCT. Herein, we present the experience of the acute leukemia working party (ALWP) of the EBMT in this age group. We analyzed a cohort of 142 patients transplanted in first remission with a median age of 62 (range 60–76 years) and a median follow-up period of 36 months post-transplant. At 3 years, overall survival (OS) and leukemia-free survival were 42% and 35%, respectively. Multivariate analyses identified cytomegalovirus (CMV) donor-recipient matching (CMV D+/R+) to be significantly associated with inferior OS. Patients transplanted from unrelated donors experienced increased grade II-IV acute graft versus host disease compared to those receiving grafts from matched related donors [Hazard ratio (HR) of 3.7, 95% confidence interval (CI), 1.75–7.8; p = 0.0005). Outcome was not impacted by Philadelphia chromosome status. A select subset of older ALL patients will benefit from extended survival and a disease free state following HSCT.

Dissecting the mechanisms involved in anti-human T-lymphocyte immunoglobulin (ATG)-induced tolerance in the setting of allogeneic stem cell transplantation - potential implications for graft versus host disease

Polyclonal anti-human thymocyte globulins (ATG) have been recently shown to significantly reduce the incidence of graft versus host disease (GVHD) post allogeneic stem cell transplantation (HSCT) from both sibling and unrelated donors. Induction of regulatory T cells has been suggested as one of the possible mechanisms. The aim of current study was to further characterize the T cell populations induced by ATG treatment and to delineate the mechanisms involved in ATG-induced tolerance. Phenotypic characterization revealed a significant increase in the expression of FoxP3, GITR, CD95, PD-1 and ICOS as well as the complement inhibitory molecules CD55, CD58 and CD59 on CD4+CD25+ T cells upon ATG treatment. Addition of ATG-treated cells to autologous and allogeneic peripheral blood mononuclear cells (PBMCs) stimulated with anti-CD3/anti-CD28 antibodies resulted in significant inhibition of proliferation. Moreover, T-cell activation and IFNγ secretion were reduced in the presence of ATG-induced Treg cells. The CD4+CD25+CD127-low Treg fraction sorted from ATG-treated culture demonstrated greater suppressive potency than negative fraction. Conditioned medium produced by ATG-treated but not IgG-treated cells contained TGFβ and suppressed T cell proliferation and activation in a TGFβ receptor-dependent manner. TGFβ receptor kinase inhibitor SB431542 interfered with the suppressive activity of ATG-primed cells, enabling partial rescue of proliferation and IFNγ secretion. Moreover, SB431542 prevented Treg phenotype induction upon ATG treatment. Altogether, our data reveal the role of TGFβ signaling in ATG-mediated immunosuppression and further support the use of ATG, a potent inducer of regulatory T cells, for prevention of GVHD post HSCT and potentially other therapeutic applications.

Thiotepa-based conditioning versus total body irradiation as myeloablative conditioning prior to allogeneic stem cell transplantation for acute lymphoblastic leukemia: A matched-pair analysis from the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation

The optimal conditioning regimen to employ before hematopoietic stem cell transplantation in acute lymphoblastic leukemia (ALL) is still undecided, and while cyclophosphamide/total body irradiation (Cy/TBI) is the most commonly used myeloablative regimen, there are concerns regarding long-term toxicity for patients conditioned with this regimen. Thiotepa-based conditioning is an emerging radiation-free regimen with recent publications indicative of comparable clinical outcomes to TBI-based conditioning. In this analysis of the acute leukemia working party of the EBMT, we performed a retrospective matched-pair analysis, evaluating the outcome of adult patients with ALL who received thiotepa-based conditioning (n = 180) with those receiving Cy/TBI conditioning (n = 540). The 2-year leukemia-free survival and overall survival (OS) rates of both conditioning regimens were comparable, 33% for thiotepa [95% confidence interval (CI): 26.4-42.8] versus 39% for Cy/TBI (95% CI: 34.8-44.5] (P = .33) and 46.5% [95% CI: 38.6-56.1] versus 48.8% [95% CI: 44.2-54] (P = .9), respectively. There was no significant difference between the two regimens in the incidence of either acute graft versus host disease (GVHD) or chronic GVHD. Multivariate analysis demonstrated increased relapse incidence for thiotepa conditioning compared to Cy/TBI (HR = 1.78, 95% CI, 1.07-2.95; P = .03) which did not affect OS. Our results indicate that thiotepa-based conditioning may not be inferior to Cy/TBI for adult patients with ALL.

ABO incompatibility in mismatched unrelated donor allogeneic hematopoietic cell transplantation for acute myeloid leukemia: A report from the acute leukemia working party of the EBMT

ABO incompatibility is commonly observed in stem cell transplantation and its impact in this setting has been extensively investigated. HLA-mismatched unrelated donors (MMURD) are often used as an alternative stem cell source but are associated with increased transplant related complications. Whether ABO incompatibility affects outcome in MMURD transplantation for acute myeloid leukemia (AML) patients is unknown. We evaluated 1,013 AML patients who underwent MMURD transplantation between 2005 and 2014. Engraftment rates were comparable between ABO matched and mismatched patients, as were relapse incidence [34%; 95% confidence interval (CI), 28-39; for ABO matched vs. 36%; 95% CI, 32-40; for ABO mismatched; P = .32], and nonrelapse mortality (28%; 95% CI, 23-33; for ABO matched vs. 25%; 95% CI, 21-29; for ABO mismatched; P = .2). Three year survival was 40% for ABO matched and 43% for ABO mismatched patients (P = .35), Leukemia free survival rates were also comparable between groups (37%; 95% CI, 32-43; for ABO matched vs. 38%; 95% CI, 33-42; for ABO mismatched; P = .87). Incidence of grade II-IV acute graft versus host disease was marginally lower in patients with major ABO mismatching (Hazard ratio of 0.7, 95% CI, 0.5-1; P = .049]. ABO incompatibility probably has no significant clinical implications in MMURD transplantation.

Long term impact of hyperleukocytosis in newly diagnosed acute myeloid leukemia patients undergoing allogeneic stem cell transplantation: An analysis from the acute leukemia working party of the EBMT

Up to 20% of acute myeloid leukemia (AML) patients present initially with hyperleukocytosis, placing them at increased risk for early mortality during induction. Yet, it is unknown whether hyperleukocytosis still retains prognostic value for AML patients undergoing hematopoietic stem cell transplantation (HSCT). Furthermore, it is unknown whether hyperleukocytosis holds prognostic significance when modern molecular markers such as FLT3-ITD and NPM1 are accounted for. To determine whether hyperleukocytosis is an independent prognostic factor influencing outcome in transplanted AML patients we performed a retrospective analysis using the registry of the acute leukemia working party of the European Society of Blood and Marrow Transplantation. A cohort of 357 patients with hyperleukocytosis (159 patients with white blood count [WBC] 50 K-100 K, 198 patients with WBC ≥ 100 K) was compared to 918 patients without hyperleukocytosis. Patients with hyperleukocytosis were younger, had an increased rate of favorable risk cytogenetics, and more likely to be FLT3 and NPM1 mutated. In multivariate analysis, hyperleukocytosis was independently associated with increased relapse incidence (hazard ratio [HR] of 1.55, 95% confidence interval [CI], 1.14-2.12; P = .004), decreased leukemia-free survival (HR of 1.38, 95% CI, 1.07-1.78; P = .013), and inferior overall survival (HR of 1.4, 95% CI, 1.07-1.84; P = .013). Hyperleukocytosis retains a significant prognostic role for AML patients undergoing HSCT.

Impact of FAB classification on predicting outcome in acute myeloid leukemia, not otherwise specified, patients undergoing allogeneic stem cell transplantation in CR1: An analysis of 1690 patients from the acute leukemia working party of EBMT

The French, American, and British (FAB) classification system for acute myeloid leukemia (AML) is extensively used and is incorporated into the AML, not otherwise specified (NOS) category in the 2016 WHO edition of myeloid neoplasm classification. While recent data proposes that FAB classification does not provide additional prognostic information for patients for whom NPM1 status is available, it is unknown whether FAB still retains a current prognostic role in predicting outcome of AML patients undergoing allogeneic stem cell transplantation. Using the European Society of Blood and Bone Marrow Transplantation registry we analyzed outcome of 1690 patients transplanted in CR1 to determine if FAB classification provides additional prognostic value. Multivariate analysis revealed that M6/M7 patients had decreased leukemia free survival (hazard ratio (HR) of 1.41, 95% confidence interval (CI), 1.01-1.99; P = .046) in addition to increased nonrelapse mortality (NRM) rates (HR, 1.79; 95% CI, 1.06-3.01; P = .028) compared with other FAB types. In the NPM1^wt AML, NOS cohort, FAB M6/M7 was also associated with increased NRM (HR, 2.17; 95% CI, 1.14-4.16; P = .019). Finally, in FLT3-ITD⁺ patients, multivariate analyses revealed that specific FAB types were tightly associated with adverse outcome. In conclusion, FAB classification may predict outcome following transplantation in AML, NOS patients.

Impact of ABO incompatibility on patients' outcome after haploidentical hematopoietic stem cell transplantation for acute myeloid leukemia - a report from the Acute Leukemia Working Party of the EBMT

A significant proportion of hematopoietic stem cell transplants are performed with ABO-mismatched donors. The impact of ABO mismatch on outcome following transplantation remains controversial and there are no published data regarding the impact of ABO mismatch in acute myeloid leukemia patients receiving haploidentical transplants. Using the European Blood and Marrow Transplant Acute Leukemia Working Group registry we identified 837 patients who underwent haploidentical transplantation. Comparative analysis was performed between patients who received ABO-matched versus ABO-mismatched haploidentical transplants for common clinical outcome variables. Our cohort consisted of 522 ABO-matched patients and 315 ABO-mismatched patients including 150 with minor, 127 with major, and 38 with bi-directional ABO mismatching. There were no significant differences between ABO matched and mismatched patients in terms of baseline disease and clinical characteristics. Major ABO mismatching was associated with inferior day 100 engraftment rate whereas multivariate analysis showed that bi-directional mismatching was associated with increased risk of grade II–IV acute graft-versus-host disease [hazard ratio (HR) 2.387; 95% confidence interval (CI): 1.22–4.66; P=0.01). Non-relapse mortality, relapse incidence, leukemia-free survival, overall survival, and chronic graft-versus-host disease rates were comparable between ABO-matched and -mismatched patients. Focused analysis on stem cell source showed that patients with minor mismatching transplanted with bone marrow grafts experienced increased grade II–IV acute graft-versus-host disease rates (HR 2.03; 95% CI: 1.00–4.10; P=0.04). Patients with major ABO mismatching and bone marrow grafts had decreased survival (HR=1.82; CI 95%: 1.048 – 3.18; P=0.033). In conclusion, ABO incompatibility has a marginal but significant clinical effect in acute myeloid leukemia patients undergoing haploidentical transplantation.

Established and emerging targeted therapies in the myelodysplastic syndromes

INTRODUCTION

Therapy for the myelodysplastic syndromes (MDS) is an evolving area of research which has made significant use of the increased understanding of the complex biology of these disorders. Novel agents targeting multiple pathogenic pathways are being actively tested in preclinical and clinical settings and hold the potential to be available to clinicians before long.

AREAS COVERED

Herein we provide an historical framework for understanding the current use of hypomethylating agents in MDS and discuss recent developments in the field of targeted therapy in MDS including data from published and ongoing clinical studies with oral hypomethylating agents, PI3/polo-like kinase inhibitors, TGF-β inhibitor/ligand traps, and immune checkpoint inhibitors. A comprehensive review of recent literature was undertaken using PubMed and Medline. Expert commentary: Management of MDS patients will evolve substantially in the near future with the incorporation of molecular data into patient stratification models and with the introduction of novel targeted agents.