North American Blastic Plasmacytoid Dendritic Cell Neoplasm Consortium: position on standards of care and areas of need.

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare hematologic malignancy with historically poor outcomes and no worldwide consensus treatment approach. Unique among most hematologic malignancies for its frequent cutaneous involvement, BPDCN can also invade other extramedullary compartments, including the central nervous system. Generally affecting older adults, many patients are unfit to receive intensive chemotherapy, and although hematopoietic stem cell transplantation is preferred for younger, fit individuals, not all are eligible. One recent therapeutic breakthrough is that all BPDCNs express CD123 (IL3Rα) and that this accessible surface marker can be pharmacologically targeted. The first-in-class agent for BPDCN, tagraxofusp, which targets CD123, was approved in December 2018 in the United States for patients with BPDCN aged ≥2 years. Despite favorable response rates in the frontline setting, many patients still relapse in the setting of monotherapy, and outcomes in patients with relapsed/refractory BPDCN remain dismal. Therefore, novel approaches targeting both CD123 and other targets are actively being investigated. To begin to formally address the state of the field, we formed a new collaborative initiative, the North American BPDCN Consortium (NABC). This group of experts, which includes a multidisciplinary panel of hematologists/oncologists, hematopoietic stem cell transplant physicians, pathologists, dermatologists, and pediatric oncologists, was tasked with defining the current standard of care in the field and identifying the most important research questions and future directions in BPDCN. The position findings of the NABC's inaugural meetings are presented herein.

Quizartinib plus chemotherapy in newly diagnosed patients with FLT3-internal-tandem-duplication-positive acute myeloid leukaemia (QuANTUM-First): a randomised, double-blind, placebo-controlled, phase 3 trial.

BACKGROUND: Patients with acute myeloid leukaemia (AML) positive for internal tandem duplication (ITD) mutations of FLT3 have poor outcomes. Quizartinib, an oral, highly potent, selective, type 2 FLT3 inhibitor, plus chemotherapy showed antitumour activity with an acceptable safety profile in patients with FLT3-ITD-positive newly diagnosed AML. The aim of the study was to compare the effect of quizartinib versus placebo on overall survival in patients with FLT3-ITD-positive newly diagnosed AML aged 18-75 years. METHODS: We conducted a randomised, double-blind, placebo-controlled, phase 3 trial comparing quizartinib and placebo in combination with chemotherapy in induction and consolidation, followed by quizartinib or placebo single-agent continuation, in patients with FLT3-ITD-positive newly diagnosed AML at 193 hospitals and clinics in 26 countries in Europe; North America; and Asia, Australia, and South America. Patients aged 18-75 years were eligible. Patients were randomly assigned (1:1) to the quizartinib group or the placebo group by an independent biostatistician through an interactive web and voice response system, stratified by region, age, and white blood cell count at diagnosis. Patients, investigators, funders, and contract research organisations were masked to treatments assigned. Induction therapy comprised a standard 7 + 3 induction regimen of cytarabine 100 mg/m2 per day (or 200 mg/m2 per day allowed if institutional or local standard) by continuous intravenous infusion from day 1 to day 7 and anthracycline (daunorubicin 60 mg/m2 per day or idarubicin 12 mg/m2 per day) by intravenous infusion on days 1, 2, and 3, then quizartinib 40 mg orally or placebo once per day, starting on day 8, for 14 days. Patients with complete remission or complete remission with incomplete neutrophil or platelet recovery received standard consolidation with high-dose cytarabine plus quizartinib (40 mg per day orally) or placebo, allogeneic haematopoietic cell transplantation (allo-HCT), or both as consolidation therapy, followed by continuation of single-agent quizartinib or placebo for up to 3 years. The primary outcome was overall survival, defined as time from randomisation until death from any cause and assessed in the intention-to-treat population. Safety was evaluated in all patients who received at least one dose of quizartinib or placebo. This study is registered with ClinicalTrials.gov (NCT02668653). FINDINGS: Between Sept 27, 2016, and Aug 14, 2019, 3468 patients with AML were screened and 539 patients (294 [55%] male patients and 245 [45%] female patients) with FLT3-ITD-positive AML were included and randomly assigned to the quizartinib group (n=268) or placebo group (n=271). 148 (55%) of 268 patients in the quizartinib group and 168 (62%) of 271 patients in the placebo group discontinued the study, primarily because of death (133 [90%] of 148 in the quizartinib group vs 158 [94%] of 168 in the placebo group) or withdrawal of consent (13 [9%] of 148 in the quizartinib group vs 9 [5%] of 168 in the placebo group). Median age was 56 years (range 20-75, IQR 46·0-65·0). At a median follow-up of 39·2 months (IQR 31·9-45·8), median overall survival was 31·9 months (95% CI 21·0-not estimable) for quizartinib versus 15·1 months (13·2-26·2) for placebo (hazard ratio 0·78, 95% CI 0·62-0·98, p=0·032). Similar proportions of patients in the quizartinib and placebo groups had at least one adverse event (264 [100%] of 265 in the quizartinib group and 265 [99%] of 268 in the placebo group) and one grade 3 or higher adverse event (244 [92%] of 265 in the quizartinib group and 240 [90%] of 268 in the placebo group). The most common grade 3 or 4 adverse events were febrile neutropenia, hypokalaemia, and pneumonia in both groups and neutropenia in the quizartinib group. INTERPRETATION: The addition of quizartinib to standard chemotherapy with or without allo-HCT, followed by continuation monotherapy for up to 3 years, resulted in improved overall survival in adults aged 18-75 years with FLT3-ITD-positive newly diagnosed AML. Based on the results from the QuANTUM-First trial, quizartinib provides a new, effective, and generally well tolerated treatment option for adult patients with FLT3-ITD-positive newly diagnosed AML. FUNDING: Daiichi Sankyo.

Follow-up of patients with R/R FLT3-mutation-positive AML treated with gilteritinib in the phase 3 ADMIRAL trial.

The phase 3 ADMIRAL (NCT02421939; Study ID: 2215-CL-0301) trial showed superior overall survival in patients with relapsed/refractory FLT3-mutation-positive acute myeloid leukemia (AML) randomized 2:1 to receive the oral FMS-like tyrosine kinase 3 inhibitor gilteritinib vs those randomized to receive salvage chemotherapy (SC). Here we provide a follow-up of the ADMIRAL trial 2 years after the primary analysis to clarify the long-term treatment effects and safety of gilteritinib in these patients with AML. At the time of this analysis, the median survival follow-up was 37.1 months, with deaths in 203 of 247 and 97 of 124 patients in the gilteritinib and SC arms, respectively; 16 gilteritinib-treated patients remained on treatment. The median overall survival for the gilteritinib and SC arms was 9.3 and 5.6 months, respectively (hazard ratio, 0.665; 95% confidence interval [CI], 0.518, 0.853; two-sided P = .0013); 2-year estimated survival rates were 20.6% (95% CI, 15.8, 26.0) and 14.2% (95% CI, 8.3, 21.6). The gilteritinib-arm 2-year cumulative incidence of relapse after composite complete remission was 75.7%, with few relapses occurring after 18 months. Overall, 49 of 247 patients in the gilteritinib arm and 14 of 124 patients in the SC arm were alive for ≥2 years. Twenty-six gilteritinib-treated patients remained alive for ≥2 years without relapse; 18 of these patients underwent transplantation (hematopoietic stem cell transplantation [HSCT]) and 16 restarted gilteritinib as post-HSCT maintenance therapy. The most common adverse events of interest during years 1 and 2 of gilteritinib therapy were increased liver transaminase levels; adverse event incidence decreased in year 2. Thus, continued and post-HSCT gilteritinib maintenance treatment sustained remission with a stable safety profile. These findings confirm that prolonged gilteritinib therapy is safe and is associated with superior survival vs SC. This trial was registered at www.clinicaltrials.gov as #NCT02421939.

Hypomethylating agents are associated with high rates of hematologic toxicity in patients with secondary myeloid neoplasms developing after acquired aplastic anemia.

Not available.

Clinical outcomes of hypomethylating agents plus Venetoclax as frontline treatment in patients 75 years and older with acute myeloid leukemia: Real-world data from eight US academic centers.

Venetoclax (VEN) combined with hypomethylating agents (HMAs) is the standard of care for the treatment of patients with newly diagnosed acute myeloid leukemia (AML) unfit for intensive chemotherapy. To date, real-world data published on HMAs plus VEN have been either single-center studies or using community-based electronic databases with limited details on mutational landscape, tolerability, and treatment patterns in elderly patients. Therefore, we conducted a multicenter retrospective study to assess the real-world experience of 204 elderly patients (≥75 years) with newly diagnosed AML treated with HMAs plus VEN from eight academic centers in the United States. Overall, 64 patients achieved complete remission (CR; 38%) and 43 CR with incomplete count recovery (CRi; 26%) for a CR/CRi rate of 64%, with a median duration of response of 14.2 months (95% CI: 9.43, 22.1). Among responders, 63 patients relapsed (59%) with median overall survival (OS) after relapse of 3.4 months (95% CI, 2.4, 6.7). Median OS for the entire population was 9.5 months (95% CI, 7.85-13.5), with OS significantly worse among patients with TP53-mutated AML (2.5 months) and improved in patients harboring NPM1, IDH1, and IDH2 mutations (13.5, 18.3, and 21.1 months, respectively). The 30-day and 60-day mortality rates were 9% and 19%, respectively. In conclusion, HMAs plus VEN yielded high response rates in elderly patients with newly diagnosed AML. The median OS was inferior to that reported in the VIALE-A trial. Outcomes are dismal after failure of HMAs plus VEN, representing an area of urgent unmet clinical need.

Acute Myeloid Leukemia, Version 3.2023, NCCN Clinical Practice Guidelines in Oncology.

Acute myeloid leukemia (AML) is a heterogeneous hematologic malignancy characterized by the clonal expansion of myeloid blasts in the peripheral blood, bone marrow, and/or other tissues. It is the most common form of acute leukemia among adults and accounts for the largest number of annual deaths from leukemias in the United States. Like AML, blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a myeloid malignancy. It is a rare malignancy characterized by the aggressive proliferation of precursors of plasmacytoid dendritic cells that frequently involves the bone marrow, skin, central nervous system, and other organs and tissues. This discussion section focuses on the diagnosis and management of BPDCN as outlined in the NCCN Guidelines for AML.

Real-world effectiveness of intensive chemotherapy with 7&3 versus venetoclax and hypomethylating agent in acute myeloid leukemia.

Intensive chemotherapy with cytarabine and anthracycline (7&3) remains the standard therapy for patients medically fit for induction, but the assessment of fitness remains controversial. Venetoclax and hypomethylating agent (ven/HMA) combination therapy has improved outcomes in unfit patients but no prospective study has assessed ven/HMA versus 7&3 as initial therapy in older, fit patients. Given no studies and expectation of ven/HMA use in patients outside of trial criteria, we evaluated retrospective outcomes among newly diagnosed patients. A nationwide electronic health record (EHR)-derived database and the University of Pennsylvania EHR identified 312 patients receiving 7&3 and 488 receiving ven/HMA who were 60-75 years old without history of organ failure. Ven/HMA patients were older and more likely to have secondary AML, adverse cytogenetics, and adverse mutations. Median overall survival (OS) for patients receiving intensive chemotherapy was 22 versus 10 months for ven/HMA (HR 0.53, 95% CI 0.40-0.60). Controlling for measured baseline characteristic imbalances reduced survival advantage by half (HR 0.71, 95% CI 0.53-0.94). A sub-group of patients with equipoise, likelihood at least 30%-70% of receiving either treatment, had similar OS outcomes (HR 1.10, 95% CI 0.75-1.6). Regarding safety outcomes, 60-day mortality was higher for ven/HMA (15% vs. 6% at 60 days) despite higher documented infections and febrile neutropenia for 7&3. In this multicenter real-word dataset, patients selected for intensive chemotherapy had superior OS but a large group had similar outcomes with ven/HMA. Prospective randomized studies, controlling for both measured and unmeasured confounders, must confirm this outcome.

Gilteritinib or Chemotherapy for Relapsed or Refractory FLT3-Mutated AML.

BACKGROUND: Patients with relapsed or refractory acute myeloid leukemia (AML) with mutations in the FMS-like tyrosine kinase 3 gene (FLT3) infrequently have a response to salvage chemotherapy. Gilteritinib is an oral, potent, selective FLT3 inhibitor with single-agent activity in relapsed or refractory FLT3-mutated AML. METHODS: In a phase 3 trial, we randomly assigned adults with relapsed or refractory FLT3-mutated AML in a 2:1 ratio to receive either gilteritinib (at a dose of 120 mg per day) or salvage chemotherapy. The two primary end points were overall survival and the percentage of patients who had complete remission with full or partial hematologic recovery. Secondary end points included event-free survival (freedom from treatment failure [i.e., relapse or lack of remission] or death) and the percentage of patients who had complete remission. RESULTS: Of 371 eligible patients, 247 were randomly assigned to the gilteritinib group and 124 to the salvage chemotherapy group. The median overall survival in the gilteritinib group was significantly longer than that in the chemotherapy group (9.3 months vs. 5.6 months; hazard ratio for death, 0.64; 95% confidence interval [CI], 0.49 to 0.83; P<0.001). The median event-free survival was 2.8 months in the gilteritinib group and 0.7 months in the chemotherapy group (hazard ratio for treatment failure or death, 0.79; 95% CI, 0.58 to 1.09). The percentage of patients who had complete remission with full or partial hematologic recovery was 34.0% in the gilteritinib group and 15.3% in the chemotherapy group (risk difference, 18.6 percentage points; 95% CI, 9.8 to 27.4); the percentages with complete remission were 21.1% and 10.5%, respectively (risk difference, 10.6 percentage points; 95% CI, 2.8 to 18.4). In an analysis that was adjusted for therapy duration, adverse events of grade 3 or higher and serious adverse events occurred less frequently in the gilteritinib group than in the chemotherapy group; the most common adverse events of grade 3 or higher in the gilteritinib group were febrile neutropenia (45.9%), anemia (40.7%), and thrombocytopenia (22.8%). CONCLUSIONS: Gilteritinib resulted in significantly longer survival and higher percentages of patients with remission than salvage chemotherapy among patients with relapsed or refractory FLT3-mutated AML. (Funded by Astellas Pharma; ADMIRAL ClinicalTrials.gov number, NCT02421939.).

Biocoating-A Critical Step Governing the Oral Delivery of Polymeric Nanoparticles.

Decades of research into the topic of oral nanoparticle (NP) delivery has still not provided a clear consensus regarding which properties produce an effective oral drug delivery system. The surface properties-charge and bioadhesiveness-as well as in vitro and in vivo correlation seem to generate the greatest number of disagreements within the field. Herein, a mechanism underlying the in vivo behavior of NPs is proposed, which bridges the gaps between these disagreements. The mechanism relies on the idea of biocoating-the coating of NPs with mucus-which alters their surface properties, and ultimately their systemic uptake. Utilizing this mechanism, several coated NPs are tested in vitro, ex vivo, and in vivo, and biocoating is found to affect NPs size, zeta-potential, mucosal diffusion coefficient, the extent of aggregation, and in vivo/in vitro/ex vivo correlation. Based on these results, low molecular weight polylactic acid exhibits a 21-fold increase in mucosal diffusion coefficient after precoating as compared to uncoated particles, as well as 20% less aggregation, and about 30% uptake to the blood in vivo. These discoveries suggest that biocoating reduces negative NP charge which results in an enhanced mucosal diffusion rate, increased gastrointestinal retention time, and high systemic uptake.

Characteristics and outcome of patients with core-binding factor acute myeloid leukemia and FLT3-ITD: results from an international collaborative study.

The aim of this study was to evaluate the prognostic impact of FLT3-ITD in core-binding factor acute myeloid leukemia (CBFAML) in an international, multicenter survey of 97 patients of whom 52% had t(8;21)(q22;q22) and 48% had inv(16)(p13q22)/t(16;16)(p13;q22). The median age of the patients was 53 years (range, 19-81). Complete remission after anthracycline-based induction (n=86) and non-intensive therapy (n=11) was achieved in 97% and 36% of the patients, respectively. The median follow-up was 4.43 years (95% confidence interval [95% CI]: 3.35-7.39 years). The median survival after intensive and non-intensive treatment was not reached and 0.96 years, respectively. Among intensively treated patients, inv(16) with trisomy 22 (n=11) was associated with a favorable 4-year relapse-free survival rate of 80% (95% CI: 59-100%) as compared to 38% (95% CI: 27-54%; P=0.02) in all other patients with CBFAML/ FLT3-ITD (n=75). Overall, 24 patients underwent allogeneic hematopoietic cell transplantation (HCT), 12 in first complete remission and 12 after relapse. Allogeneic HCT in first complete remission was not beneficial (P=0.60); however, allogeneic HCT seemed to improve median survival in relapsed patients compared to that of patients treated with chemotherapy (not reached vs. 0.6 years, respectively; P=0.002). Excluding patients with inv(16) with trisomy 22, our data indicate that compathe outcome of CBF-AML patients with FLT3-ITD may be inferior to that of patients without FLT3-ITD (based on previously published data), suggesting that prognostically CBF-AML patients with FLT3-ITD should not be classified as favorable-risk. FLT3-inhibitors may improve the outcome of these patients.

Gilteritinib clinical activity in relapsed/refractory FLT3 mutated acute myeloid leukemia previously treated with FLT3 inhibitors.

Gilteritinib is approved for the treatment of relapsed/refractory (R/R) acute myeloid leukemia (AML) with an FLT3-mutation (FLT3mut+ ). However, the gilteritinib phase 3 ADMIRAL study (Perl et al NEJM 2019) was conducted prior to widespread adoption of either midostaurin as a component of standard intensive induction and consolidation or posttransplant FLT3 inhibitor maintenance. We performed a retrospective analysis using data from 11 US centers and where we identified 113 patients who received gilteritinib alone or as combination therapy for the treatment of R/R FLT3mut+ AML. The composite complete remission (CR) rate (CRc, defined as CR + CRi + CR with incomplete platelet recovery [CRp]) was 48.7% (n = 55). The CRc rate after treatment with gilteritinib in patients who were treated with only prior 7+3 and midostaurin with or without consolidation was 58% with a median survival of 7.8 months. Survival was longest in patients who obtained a CR, particularly a cMRD (clinical minimal or measurable residual disease) negative response; this remained significant after censoring at the time of stem cell transplant. The mitogen-activated protein kinase pathway activating mutations that are known for gilteritinib resistance (NRAS, KRAS, and PTPN11) had lower CRc (35% vs. 60.5%) and lower median overall survival than patients' whose leukemia did not express these mutations (4.9 months vs. 7.8 months) (HR 2.4; 95% CI 1. 5.4) p value <.01.

Day 4 vs. day 12 G-CSF administration following reduced intensity peripheral blood allogeneic stem cell transplant.

INTRODUCTION: Granulocyte colony-stimulating factor (G-CSF) hastens neutrophil engraftment and reduces infections after allogeneic hematopoietic cell transplant (alloHCT), yet the optimal start date is unknown. Additionally, concurrent G-CSF and methotrexate for graft-vs-host disease (GVHD) prophylaxis may potentiate myelosuppression, and prolonged G-CSF is costly. Our institution changed from day + 4 to day + 12 G-CSF initiation following reduced intensity (RIC) alloHCT with methotrexate GVHD prophylaxis. METHODS: We retrospectively compared day + 4 and day + 12 G-CSF initiation after RIC alloHCT from 2017-2021. The primary endpoint was the time to neutrophil engraftment. Secondary endpoints included length of stay (LOS) and the time to platelet engraftment as well as the incidence of infectious events, acute GVHD (aGVHD), and mucositis. RESULTS: Thirty-two patients were included in each group with similar baseline characteristics. We observed faster neutrophil engraftment (median 12 vs. 15 days, p = 0.01) and platelet engraftment (median 13 vs. 15 days, p = 0.026) with day + 4 vs. day + 12 G-CSF initiation. Median LOS was 23 days (range, 19-32) with day + 4 initiation vs. 24 days (21-30) with day + 12 (p = 0.046). The incidence of culture-negative febrile neutropenia (p = 0.12), any grade aGVHD (p = 0.58), and grade 2-4 mucositis (p = 0.8) were similar between groups. CONCLUSION: Compared to day + 4, day + 12 G-CSF initiation following RIC alloHCT had a longer time to neutrophil and platelet engraftment. Day + 12 initiation also resulted in longer LOS, which while statistically significant, was potentially of limited clinical significance. These findings are hypothesis generating.

Availability of FLT3 inhibitors: how do we use them?

The natural history of FLT3-mutated AML is changing after the approval of midostaurin for frontline therapy and gilteritinib for relapsed or refractory patients. Recently reported, positive randomized trials of the drugs gilteritinib, quizartinib, and sorafenib predict even wider use of FLT3 inhibitors going forward. FLT3 inhibitors now emerge as an important, if not indispensable, part of therapy for a large subset of high-risk patients.

NCCN Guidelines Insights: Acute Myeloid Leukemia, Version 2.2021.

The NCCN Guidelines for Acute Myeloid Leukemia (AML) provide recommendations for the diagnosis and treatment of adults with AML based on clinical trials that have led to significant improvements in treatment, or have yielded new information regarding factors with prognostic importance, and are intended to aid physicians with clinical decision-making. These NCCN Guidelines Insights focus on recent select updates to the NCCN Guidelines, including familial genetic alterations in AML, postinduction or postremission treatment strategies in low-risk acute promyelocytic leukemia or favorable-risk AML, principles surrounding the use of venetoclax-based therapies, and considerations for patients who prefer not to receive blood transfusions during treatment.

Phase 2b study of 2 dosing regimens of quizartinib monotherapy in FLT3-ITD-mutated, relapsed or refractory AML.

This randomized, open-label, phase 2b study (NCT01565668) evaluated the efficacy and safety of 2 dosing regimens of quizartinib monotherapy in patients with relapsed/refractory (R/R) FLT3-internal tandem duplication (ITD)-mutated acute myeloid leukemia (AML) who previously underwent transplant or 1 second-line salvage therapy. Patients (N = 76) were randomly assigned to 30- or 60-mg/day doses (escalations to 60 or 90 mg/day, respectively, permitted for lack/loss of response) of single-agent oral quizartinib dihydrochloride. Allelic frequency of at least 10% was defined as FLT3-ITD-mutated disease. Coprimary endpoints were composite complete remission (CRc) rates and incidence of QT interval corrected by Fridericia's formula (QTcF) of more than 480 ms (grade 2 or greater). Secondary endpoints included overall survival (OS), duration of CRc, bridge to transplant, and safety. CRc rates were 47% in both groups, similar to earlier reports with higher quizartinib doses. Incidence of QTcF above 480 ms was 11% and 17%, and QTcF above 500 ms was 5% and 3% in the 30- and 60-mg groups, respectively, which is less than earlier reports with higher doses of quizartinib. Median OS (20.9 and 27.3 weeks), duration of CRc (4.2 and 9.1 weeks), and bridge to transplant rates (32% and 42%) were higher in the 60-mg groups than in the 30-mg group. Dose escalation occurred in 61% and 14% of patients in the 30- and 60-mg groups, respectively. This high clinical activity of quizartinib at the evaluated doses is consistent with previous reports with an improved safety profile. Need to dose-escalate more than half of patients who received quizartinib 30 mg also supports further investigation of treatment with quizartinib 60 mg/day.

Allogeneic hematopoietic cell transplantation improves outcome of adults with t(6;9) acute myeloid leukemia: results from an international collaborative study.

Acute myeloid leukemia (AML) with t(6;9)(p22;q34) is a distinct entity accounting for 1-2% of AML cases. A substantial proportion of these patients have a concomitant FLT3-ITD. While outcomes are dismal with intensive chemotherapy, limited evidence suggests allogeneic hematopoietic cell transplantation (allo-HCT) may improve survival if performed early during first complete remission. We report on a cohort of 178 patients with t(6;9)(p22;q34) within an international, multicenter collaboration. Median age was 46 years (range: 16-76), AML was de novo in 88%, FLT3-ITD was present in 62%, and additional cytogenetic abnormalities in 21%. Complete remission was achieved in 81% (n=144), including 14 patients who received high-dose cytarabine after initial induction failure. With a median follow up of 5.43 years, estimated overall survival at five years was 38% (95%CI: 31-47%). Allo-HCT was performed in 117 (66%) patients, including 89 in first complete remission. Allo-HCT in first complete remission was associated with higher 5-year relapse-free and overall survival as compared to consolidation chemotherapy: 45% (95%CI: 35-59%) and 53% (95%CI: 42-66%) versus 7% (95%CI: 3-19%) and 23% (95%CI: 13-38%), respectively. For patients undergoing allo-HCT, there was no difference in overall survival rates at five years according to whether it was performed in first [53% (95%CI: 42-66%)], or second [58% (95%CI: 31-100%); n=10] complete remission or with active disease/relapse [54% (95%CI: 34-84%); n=18] (P=0.67). Neither FLT3-ITD nor additional chromosomal abnormalities impacted survival. In conclusion, outcomes of t(6;9)(p22;q34) AML are poor with chemotherapy, and can be substantially improved with allo-HCT.

Risk of invasive fungal infections in patients with high-risk MDS and AML receiving hypomethylating agents.

Invasive fungal infections (IFI) are a significant source of morbidity and mortality for patients with acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS). Given the heterogeneity of the population receiving hypomethylating agents (HMA), it is difficult for clinicians to accurately assess their patients' risk of infection. Literature on the incidence of IFI following HMA is limited to several studies of azacitidine. The primary objective of this retrospective study was to establish the incidence of IFI in HMA treated AML/MDS patients at a large U.S. comprehensive cancer center. Secondary objectives included comparing incidence of IFI among pre-specified subgroups to identify potential risk factors for IFI. Two hundred three patients with AML, intermediate to very high risk MDS or chronic myelomonocytic leukemia who received at least two cycles of HMA were included. The incidence of IFI, as defined by the European Organization for Research and Treatment of Cancer / Invasive Fungal Infections Cooperative Group criteria, was 9.6%, with 20 IFI diagnosed following HMA (three proven, four probable, 13 possible). Among the proven cases of IFI, molds included Scedosporium and Fusarium spp. Eleven patients who developed IFIs were neutropenic upon initiating HMA. The majority (17/20) of infections occurred during the first four cycles. Given this incidence, mold-active prophylaxis can be considered in patients who are neutropenic at the start of therapy.

Quizartinib versus salvage chemotherapy in relapsed or refractory FLT3-ITD acute myeloid leukaemia (QuANTUM-R): a multicentre, randomised, controlled, open-label, phase 3 trial.

BACKGROUND: Patients with relapsed or refractory FLT3 internal tandem duplication (FLT3-ITD)-positive acute myeloid leukaemia have a poor prognosis, including high frequency of relapse, poorer response to salvage therapy, and shorter overall survival than those with FLT3 wild-type disease. We aimed to assess whether single-agent quizartinib, an oral, highly potent and selective type II FLT3 inhibitor, improves overall survival versus salvage chemotherapy. METHODS: QuANTUM-R is a randomised, controlled, phase 3 trial done at 152 hospitals and cancer centres in 19 countries. Eligible patients aged 18 years or older with ECOG performance status 0-2 with relapsed or refractory (duration of first composite complete remission ≤6 months) FLT3-ITD acute myeloid leukaemia after standard therapy with or without allogeneic haemopoietic stem-cell transplantation were randomly assigned (2:1; permuted block size of 6; stratified by response to previous therapy and choice of chemotherapy via a phone-based and web-based interactive response system) to quizartinib (60 mg [30 mg lead-in] orally once daily) or investigator's choice of preselected chemotherapy: subcutaneous low-dose cytarabine (subcutaneous injection of cytarabine 20 mg twice daily on days 1-10 of 28-day cycles); intravenous infusions of mitoxantrone (8 mg/m2 per day), etoposide (100 mg/m2 per day), and cytarabine (1000 mg/m2 per day on days 1-5 of up to two 28-day cycles); or intravenous granulocyte colony-stimulating factor (300 µg/m2 per day or 5 µg/kg per day subcutaneously on days 1-5), fludarabine (intravenous infusion 30 mg/m2 per day on days 2-6), cytarabine (intravenous infusion 2000 mg/m2 per day on days 2-6), and idarubicin (intravenous infusion 10 mg/m2 per day on days 2-4 in up to two 28-day cycles). Patients proceeding to haemopoietic stem-cell transplantation after quizartinib could resume quizartinib after haemopoietic stem-cell transplantation. The primary endpoint was overall survival in the intention-to-treat population. This trial is registered with ClinicalTrials.gov, number NCT02039726, and follow-up is ongoing. FINDINGS: Between May 7, 2014, and Sept 13, 2017, 367 patients were enrolled, of whom 245 were randomly allocated to quizartinib and 122 to chemotherapy. Four patients in the quizartinib group and 28 in the chemotherapy group were not treated. Median follow-up was 23·5 months (IQR 15·4-32·3). Overall survival was longer for quizartinib than for chemotherapy (hazard ratio 0·76 [95% CI 0·58-0·98; p=0·02]). Median overall survival was 6·2 months (5·3-7·2) in the quizartinib group and 4·7 months (4·0-5·5) in the chemotherapy group. The most common non-haematological grade 3-5 treatment-emergent adverse events (within ≤30 days of last dose or >30 days if suspected to be a treatment-related event) for quizartinib (241 patients) and chemotherapy (94 patients) were sepsis or septic shock (46 patients [19%] for quizartinib vs 18 [19%] for chemotherapy), pneumonia (29 [12%] vs eight [9%]), and hypokalaemia (28 [12%] vs eight [9%]). The most frequent treatment-related serious adverse events were febrile neutropenia (18 patients [7%]), sepsis or septic shock (11 [5%]), QT prolongation (five [2%]), and nausea (five [2%]) in the quizartinib group, and febrile neutropenia (five [5%]), sepsis or septic shock (four [4%]), pneumonia (two [2%]), and pyrexia (two [2%]) in the chemotherapy group. Grade 3 QT prolongation in the quizartinib group was uncommon (eight [3%] by central reading, ten [4%] by investigator report); no grade 4 events occurred. There were 80 (33%) treatment-emergent deaths in the quizartinib group (31 [13%] of which were due to adverse events) and 16 (17%) in the chemotherapy group (nine [10%] of which were due to adverse events). INTERPRETATION: Treatment with quizartinib had a survival benefit versus salvage chemotherapy and had a manageable safety profile in patients with rapidly proliferative disease and very poor prognosis. Quizartinib could be considered a new standard of care. Given that there are only a few available treatment options, this study highlights the value of targeting the FLT3-ITD driver mutation with a highly potent and selective FLT3 inhibitor. FUNDING: Daiichi Sankyo.

Heterogeneous resistance to quizartinib in acute myeloid leukemia revealed by single-cell analysis.

Genomic studies have revealed significant branching heterogeneity in cancer. Studies of resistance to tyrosine kinase inhibitor therapy have not fully reflected this heterogeneity because resistance in individual patients has been ascribed to largely mutually exclusive on-target or off-target mechanisms in which tumors either retain dependency on the target oncogene or subvert it through a parallel pathway. Using targeted sequencing from single cells and colonies from patient samples, we demonstrate tremendous clonal diversity in the majority of acute myeloid leukemia (AML) patients with activating FLT3 internal tandem duplication mutations at the time of acquired resistance to the FLT3 inhibitor quizartinib. These findings establish that clinical resistance to quizartinib is highly complex and reflects the underlying clonal heterogeneity of AML.

Potent efficacy of combined PI3K/mTOR and JAK or ABL inhibition in murine xenograft models of Ph-like acute lymphoblastic leukemia.

Philadelphia chromosome (Ph)-like B-cell acute lymphoblastic leukemia (Ph-like ALL) is associated with activated JAK/STAT, Abelson kinase (ABL), and/or phosphatidylinositol 3-kinase (PI3K) signaling and poor clinical outcomes. PI3K pathway signaling inhibitors have been minimally investigated in Ph-like ALL. We hypothesized that targeted inhibition of PI3Kα, PI3Kδ, PI3K/mTOR, or target of rapamycin complex 1/2 (TORC1/TORC2) would decrease leukemia proliferation and abrogate aberrant kinase signaling and that combined PI3K pathway and JAK inhibition or PI3K pathway and SRC/ABL inhibition would have superior efficacy compared to inhibitor monotherapy. We treated 10 childhood ALL patient-derived xenograft models harboring various Ph-like genomic alterations with 4 discrete PI3K pathway protein inhibitors and observed marked leukemia reduction and in vivo signaling inhibition in all models. Treatment with dual PI3K/mTOR inhibitor gedatolisib resulted in near eradication of ALL in cytokine receptor-like factor 2 (CRLF2)/JAK-mutant models with mean 92.2% (range, 86.0%-99.4%) reduction vs vehicle controls (P < .0001) and in prolonged animal survival. Gedatolisib also inhibited ALL proliferation in ABL/platelet-derived growth factor receptor (PDGFR)-mutant models with mean 66.9% (range, 42.0%-87.6%) reduction vs vehicle (P < .0001). Combined gedatolisib and ruxolitinib treatment of CRLF2/JAK-mutant models more effectively inhibited ALL proliferation than either inhibitor alone (P < .001) and further enhanced survival. Similarly, superior efficacy of combined gedatolisib and dasatinib was observed in ABL/PDGFR-mutant models (P < .001). Overall, PI3K/mTOR inhibition potently decreased ALL burden in vivo; antileukemia activity was further enhanced with combination inhibitor therapy. Clinical trials testing combinations of kinase inhibitors in Ph-like ALL patients are indicated.