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BMT CTN 1506 ("MORPHO"; NCT02997202) was a randomized phase 3 study of gilteritinib compared to placebo as maintenance therapy after hematopoietic stem cell transplantation (HCT) for patients with FLT3-ITD-mutated acute myeloid leukemia (AML). A key secondary endpoint was to determine the impact on survival of pre- and/or post-HCT measurable residual disease (MRD), as determined using a highly sensitive assay for FLT3-ITD mutations. Generally, gilteritinib maintenance therapy was associated with improved relapse-free survival (RFS) for participants with detectable peri-HCT MRD, whereas no benefit was evident for those lacking detectable MRD. We conducted a post-hoc analysis of the data and found that the level of MRD detected with this approach correlated remarkably with RFS and relapse risk, and that MRD detectable at any level negatively impacted RFS. In the placebo arm, 42.2% of participants with detectable FLT3-ITD MRD relapsed compared to 13.4% of those without detectable MRD. We found that 14.8% of participants had multiple FLT3-ITD clones detected as MRD and had worse survival irrespective of treatment arm. Finally, we examined the kinetics of FLT3-ITD clonal relapse or eradication and found that participants on the placebo arm with detectable MRD relapsed rapidly after HCT, often within a few weeks. MRD-positive participants on the gilteritinib arm relapsed either with FLT3 wild type clones (as assessed by capillary electrophoresis), after cessation of gilteritinib with persistent MRD, or on progression of multi-clonal disease. These data demonstrate the potential of using FLT3-ITD MRD to guide therapy with gilteritinib for this subtype of AML., (Copyright © 2025 American Society of Hematology.)

Acute myeloid leukemia (AML) is a rapidly progressive malignancy without effective therapies for refractory disease. So far, chimeric antigen receptor (CAR) T cell therapy in AML has not recapitulated the efficacy seen in B cell malignancies. Here we report a pilot study of autologous anti-CD123 CAR T cells in 12 adults with relapsed or refractory AML. CAR T cells targeting CD123 + cells were successfully manufactured in 90.4% of runs. Cytokine release syndrome was observed in 10 of 12 infused individuals (83.3%, 90% confidence interval 0.5-0.97). Three individuals achieved clinical response (25%, 90% confidence interval 0.07-0.53). We found that myeloid-supporting cytokines are secreted during cell therapy and support AML blast survival via kinase signaling, leading to CAR T cell exhaustion. The prosurvival effect of therapy-induced cytokines presents a unique resistance mechanism in AML that is distinct from any observed in B cell malignancies. Our findings suggest that autologous CART manufacturing is feasible in AML, but treatment is associated with high rates of cytokine release syndrome and relatively poor clinical efficacy. Combining CAR T cell therapies with cytokine signaling inhibitors could enhance immunotherapy efficacy in AML and achieve improved outcomes (ClinicalTrials.gov identifier: NCT03766126 )., Competing Interests: Competing interests: D.L.P. declares funding from the National Marrow Donor Program; membership on an entity’s Board of Directors or advisory committees of Kite/Gilead, Janssen, Genentech, DeCart, Sana Biotechnology, Verismo and Novartis; is a current equity holder of the American Society for Transplantation and Cellular Therapy and Verismo; declares honoraria for Incyte; and has patents and royalties in Tmunity and Wiley and Sons Publishing. J.A.F. is a member of the scientific advisory boards of Cartography Bio and Shennon Biotechnologies and has patents, royalties and other intellectual property. M.R.L. is an employee of Hematoloics, Inc. J.L.B. is an employee of Novartis. C.H.J. is an inventor of patents related to CAR therapy products and may be eligible to receive a select portion of royalties paid from Kite to the University of Pennsylvania. C.H.J. is a scientific cofounder and holds equity in Capstan Therapeutics, Dispatch Biotherapeutics and Bluewhale Bio. C.H.J. serves on the board of AC Immune and is a scientific advisor to BlueSphere Bio, Cabaletta, Carisma, Cartography, Cellares, Cellcarta, Celldex, Danaher, Decheng, ImmuneSensor, Kite, Poseida, Verismo, Viracta and WIRB-Copernicus group. S.I.G. has patents related to CAR therapy with royalties paid from Novartis to the University of Pennsylvania. S.I.G. is a scientific cofounder and holds equity in Interius Biotherapeutics and Carisma Therapeutics. S.I.G. is a scientific advisor to Carisma, Cartography, Currus, Interius, Kite, NKILT and Mission Bio. The other authors declare no competing interests., (© 2024. The Author(s), under exclusive licence to Springer Nature America, Inc.)

Combining FLT3 inhibitors with intensive chemotherapy and transplant has substantially improved AML outcomes, prompting a recent re-evaluation of FLT3-ITD's historically negative prognostic effect. Treatment approaches may soon undergo major changes as emerging data suggest maximal intensity does not benefit all patients and MRD potentially can guide several treatment choices. Finally, recent data also suggest FLT3 inhibitors could transform outcomes in patients unsuitable for intensive therapy. If confirmed, this has important implications for fit patients and could revolutionize the treatment paradigm., (Copyright © 2024 American Society of Hematology.)

Abstract: The Blood and Marrow Transplant (BMT) Clinical Trials Network conducted a phase 3 randomized trial comparing gilteritinib with placebo after allogeneic hematopoietic cell transplantation (HCT) for FLT3-ITD+ acute myeloid leukemia (AML). The primary analysis demonstrated no statistically significant difference in relapse-free survival (RFS); however, patients with FLT3-ITD measurable residual disease (MRD) peri-HCT had significantly longer RFS with gilteritinib. This analysis investigates the effect of post-HCT gilteritinib vs placebo on health-related quality of life (HRQOL). HRQOL was measured with Functional Assessment of Cancer Therapy-Bone Marrow Transplant (FACT-BMT), FACT-Leukemia (FACT-Leu), and EuroQOL-5 Dimensions (EQ-5D-5L) at post-HCT randomization; day 29; months 3, 6, 12, 18, 24; and/or end of therapy. HRQOL and clinically meaningful differences were summarized using descriptive statistics and compared using mixed model repeated measures to evaluate longitudinal change from baseline and stratified Cox model to evaluate time to improvement. HRQOL completion rate was acceptable (>70%) across all time points and measures. There were no differences in HRQOL scores at any time point between cohorts. Clinically meaningful and time to improvement in HRQOL were similar in both arms. Despite higher treatment-emergent adverse effects with gilteritinib, response to the question of being "bothered by side effects of treatment" did not differ between groups. Subgroup analysis of MRD-positive and negative patients demonstrated no differences in HRQOL between arms. For patients with FLT3-ITD+ AML undergoing HCT, gilteritinib maintenance was not associated with any difference in HRQOL or patient-reported impact of side effects. This trial was registered at www.ClinicalTrials.gov as #NCT02997202., (Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0), permitting only noncommercial, nonderivative use with attribution.)

Despite recent work linking mixed phenotype acute leukemia (MPAL) to certain genetic lesions, specific driver mutations remain undefined for a significant proportion of patients and no genetic subtype is predictive of clinical outcomes. Moreover, therapeutic strategy for MPAL remains unclear, and prognosis is overall poor. We performed multiomic single cell profiling of 14 newly diagnosed adult MPAL patients to characterize the inter- and intra-tumoral transcriptional, immunophenotypic, and genetic landscapes of MPAL. We show that neither genetic profile nor transcriptome reliably correlate with specific MPAL immunophenotypes. Despite this, we find that MPAL blasts express a shared stem cell-like transcriptional profile indicative of high differentiation potential. Patients with the highest differentiation potential demonstrate inferior survival in our dataset. A gene set score, MPAL95, derived from genes highly enriched in the most stem-like MPAL cells, is applicable to bulk RNA sequencing data and is predictive of survival in an independent patient cohort, suggesting a potential strategy for clinical risk stratification., (© 2024. The Author(s).)

Purpose: Allogeneic hematopoietic cell transplantation (HCT) improves outcomes for patients with AML harboring an internal tandem duplication mutation of FLT3 ( FLT3-ITD ) AML. These patients are routinely treated with a FLT3 inhibitor after HCT, but there is limited evidence to support this. Accordingly, we conducted a randomized trial of post-HCT maintenance with the FLT3 inhibitor gilteritinib (ClinicalTrials.gov identifier: NCT02997202) to determine if all such patients benefit or if detection of measurable residual disease (MRD) could identify those who might benefit., Methods: Adults with FLT3-ITD AML in first remission underwent HCT and were randomly assigned to placebo or 120 mg once daily gilteritinib for 24 months after HCT. The primary end point was relapse-free survival (RFS). Secondary end points included overall survival (OS) and the effect of MRD pre- and post-HCT on RFS and OS., Results: Three hundred fifty-six participants were randomly assigned post-HCT to receive gilteritinib or placebo. Although RFS was higher in the gilteritinib arm, the difference was not statistically significant (hazard ratio [HR], 0.679 [95% CI, 0.459 to 1.005]; two-sided P = .0518). However, 50.5% of participants had MRD detectable pre- or post-HCT, and, in a prespecified subgroup analysis, gilteritinib was beneficial in this population (HR, 0.515 [95% CI, 0.316 to 0.838]; P = .0065). Those without detectable MRD showed no benefit (HR, 1.213 [95% CI, 0.616 to 2.387]; P = .575)., Conclusion: Although the overall improvement in RFS was not statistically significant, RFS was higher for participants with detectable FLT3-ITD MRD pre- or post-HCT who received gilteritinib treatment. To our knowledge, these data are among the first to support the effectiveness of MRD-based post-HCT therapy.

Hematologic malignancies disproportionately affect older adults. Hematopoietic cell transplantation (HCT) is potentially curative, but poor overall survival (OS) has limited its use in older adults. Fried's frailty phenotype (FFP) is a geriatric assessment tool that combines objective and subjective performance measures: gait speed, grip strength, activity level, exhaustion, and weight loss. People meeting ≥3 criteria are classified as frail; 1 or 2 criteria, as pre-frail; and 0 criteria, as fit. To evaluate the association of pre-HCT FFP with post-HCT outcomes, we assessed FFP prior to conditioning for 280 HCT recipients age ≥60 years with acute leukemia or a myeloid neoplasm at 3 institutions. When analyzing survival by age group, patients age ≥70 years had inferior OS compared to patients age 60 to 69 years (P = .002), with corresponding OS estimates of 38.9% (95% confidence interval [CI], 27.8% to 49.9%) and 59.3% (95% CI, 51.9% to 65.9%). Nonrelapse mortality (NRM) also was significantly higher in the older patients (P = .0005); the 2-year cumulative incidences of NRM were 38.5% (95% CI, 27.5% to 49.2%) and 17.2% (95% CI, 12.3% to 22.8%), for older and younger recipients, respectively. The cumulative incidences of relapse did not differ by age group (P = .3435). Roughly one-third (35.5%) of the patients were fit, 57.5% were pre-frail, and 7.5% were frail, with corresponding 2-year OS estimates of 68.4% (95% CI, 57.9% to 76.8%), 45.5% (95% CI, 37.4% to 53.2%), and 45.8% (95% CI, 23.4% to 65.8%) (P = .013). FFP was not significantly associated with NRM, but being frail or pre-frail was associated with a higher rate of disease-related deaths (33.3% and 27.3%, respectively, compared with 17.4% for fit patients; P = .043). In univariate modeling of restricted mean survival time with a 3-year horizon (RMST_3y), the factors that were significantly associated were FFP, age, Karnofsky Performance Status (KPS), Disease Risk Index (DRI), and HCT-specific Comorbidity Index (HCT-CI). Of those factors, only FFP (P = .006), age (P = .006), KPS (P = .004), and DRI (P = .005) were significantly associated in multivariate modeling of RMST_3y. Estimates of RMST_3y were computed and 5 risk-groups were created with survival ranging from 31.4 months for those who were age 60 to 69 years, fit, had KPS 90 to 100, and low/intermediate-risk DRI compared to 10.5 months for those who had high-risk features for all the evaluated factors. In univariate and multivariate analyses for restricted mean time to relapse with a 3-year horizon (RMRT_3y), FFP (pre-frail versus fit, P = .007; frail versus fit, P = .061) and DRI (P = .001) were the only significant factors. Predicted RMRT_3y was longest (30.6 months) for those who were fit and had low/intermediate-risk DRI scores and shortest (19.1 months) for those who were frail and had high-risk or very high-risk DRI scores. Both age and FFP impact survival after HCT. Incorporation of FFP into pre-HCT evaluations may improve decision-making and counseling regarding HCT risk for older adults. Our findings support future trials designed to reverse frailty, such as pre-HCT supervised exercise programs, and correlative analyses to unravel the connection of frailty and relapse to generate future targets for intervention. Finally, exploration of novel HCT platforms to reduce relapse in pre-frail and frail patients, as well as reduce NRM in adults age >70 years, are warranted., (Copyright © 2024 The American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc. All rights reserved.)

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., (© 2024 The Authors. American Journal of Hematology published by Wiley Periodicals LLC.)

Purpose: Gilteritinib is a type 1 FLT3 inhibitor active as monotherapy for relapsed or refractory FLT3 -mutated AML. We investigated the safety, tolerability, and efficacy of gilteritinib incorporated into intensive induction and consolidation chemotherapy, and as maintenance therapy for adult patients with newly diagnosed, non-favorable-risk AML., Methods: In this phase IB study (2215-CL-0103; ClinicalTrials.gov identifier: NCT02236013), 103 participants were screened and 80 were allocated to treatment. The study was divided into four parts: dose escalation, dose expansion, investigation of alternate anthracycline and gilteritinib schedule, and continuous gilteritinib during consolidation., Results: After dose escalation, 120 mg gilteritinib once daily was chosen for further study. There were 58 participants evaluable for response at this dose, 36 of whom harbored FLT3 mutations. For participants with FLT3 -mutated AML, the composite complete response (CRc) rate was 89% (83% were conventional complete responses), all achieved after a single induction cycle. The median overall survival time was 46.1 months. Gilteritinib was well-tolerated in this context although the median time to count recovery during induction was approximately 40 days. Longer time-to-count recovery was associated with higher trough levels of gilteritinib, which, in turn, were associated with azole use. The recommended regimen is gilteritinib at a dose of 120 mg once daily from days 4 to 17 or 8 to 21 of a 7 + 3 induction with either idarubicin or daunorubicin and from day 1 continuously with high-dose cytarabine consolidation. Maintenance therapy with gilteritinib was well-tolerated., Conclusion: These results demonstrated the safety and tolerability of gilteritinib incorporated into an induction and consolidation chemotherapy regimen, and as single-agent maintenance therapy for patients with newly diagnosed FLT3 -mutant AML. The data herein provide an important framework for the design of randomized trials comparing gilteritinib with other FLT3 inhibitors.

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., (© 2023 Wiley Periodicals LLC.)

Mixed phenotype acute leukemia (MPAL) is a leukemia whose biologic drivers are poorly understood, therapeutic strategy remains unclear, and prognosis is poor. We performed multiomic single cell (SC) profiling of 14 newly diagnosed adult MPAL patients to characterize the immunophenotypic, genetic, and transcriptional landscapes of MPAL. We show that neither genetic profile nor transcriptome reliably correlate with specific MPAL immunophenotypes. However, progressive acquisition of mutations is associated with increased expression of immunophenotypic markers of immaturity. Using SC transcriptional profiling, we find that MPAL blasts express a stem cell-like transcriptional profile distinct from other acute leukemias and indicative of high differentiation potential. Further, patients with the highest differentiation potential demonstrated inferior survival in our dataset. A gene set score, MPAL95, derived from genes highly enriched in this cohort, is applicable to bulk RNA sequencing data and was predictive of survival in an independent patient cohort, suggesting utility for clinical risk stratification., Competing Interests: Conflicts of interest: CEH, CD, YX, and KMF are employees of Fluent Biosciences. AA is a co-founder and shareholder of Mission Bio and Fluent BioSciences.

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/m 2 per day (or 200 mg/m 2 per day allowed if institutional or local standard) by continuous intravenous infusion from day 1 to day 7 and anthracycline (daunorubicin 60 mg/m 2 per day or idarubicin 12 mg/m 2 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., Competing Interests: Declaration of interests HPE reports research grants from AbbVie, Agios Pharmaceuticals, ALX Oncology, Amgen, Ascentage, Celgene, Daiichi Sankyo, Forma Therapeutics, Forty Seven, Gilead, GlycoMimetics, ImmunoGen, Jazz Pharmaceuticals, Kura Oncology, MacroGenics, Novartis, PTC Therapeutics, Servier, and Sumitomo Dainippon Pharma; consulting fees for participation on advisory boards for AbbVie, Agios Pharmaceuticals, Astellas, Bristol Myers Squibb, Celgene, Daiichi Sankyo, Genentech, GlycoMimetics, ImmunoGen, Incyte, Jazz Pharmaceuticals, Kura Oncology, MacroGenics, Novartis, Pfizer, Servier, Syros Pharmaceuticals, Takeda, and Trillium Therapeutics; payment for speakers bureaus from AbbVie, Agios Pharmaceuticals, Bristol Myers Squibb, Celgene, Incyte, Jazz Pharmaceuticals, Novartis, and Servier; and has served as a steering committee member for GlycoMimetics, as chair of the Myeloid Neoplasms Repository study for Bristol Myers Squibb and Celgene, and as chair of the independent review committee of the VIALE A and VIALE C studies for AbbVie. PM reports research grants from AbbVie, Bristol Myers Squibb, Jazz Pharmaceuticals, Menarini, Stemline Therapeutics, Novartis, Pfizer, and Takeda; consulting fees from AbbVie, Astellas, BeiGene, Bristol Myers Squibb, Gilead, Incyte, Jazz Pharmaceuticals, Kura Oncology, Menarini, Stemline Therapeutics, Nerviano Medical Sciences, Novartis, Otsuka Pharmaceutical, Pfizer, Ryvu Therapeutics, and Takeda; and payment for speakers bureaus from AbbVie, Astellas, Bristol Myers Squibb, Gilead, Jazz Pharmaceuticals, and Pfizer. H-JK reports research grants from BL&H; consulting fees from AbbVie, AIMS BioScience, Amgen, AMLHub, Astellas, Aston BioSciences, Bristol Myers Squibb, Celgene, Boryung Pharmaceutical, Daiichi Sankyo, Handok, Ingenium, Janssen, LG Chem, Novartis, Pfizer, Sanofi Genzyme, SL VaxiGen, and VigenCell; is on a data safety monitoring board or advisory board for AbbVie, the Asia Pacific Leukemia Consortium, Astellas, Bristol Myers Squibb, Celgene, Daiichi Sankyo, Handok, Janssen, Novartis, Pfizer, and Sanofi Genzyme; and is a leader in other board, society, committee, or advocacy groups for AMLHub, the Asia Pacific Leukemia Consortium, the Asia Pacific Blood and Marrow Transplantation Group, and the Korean Society of Blood and Marrow Transplantation. EP reports consulting fees from KCR US; payment for lectures from Amgen, Angelini, Astellas, Novartis, Pfizer, and Servier; and support for attending meetings from Angelini, Astellas, Bristol Myers Squibb, Jazz Pharmaceuticals, Novartis, Pfizer, and Servier. RV reports consulting fees from AbbVie, Astellas, Pfizer, and PharmaS; and payment for lectures from AbbVie, Astellas, Merck Sharp & Dohme, Novartis, Pfizer, PharmaS, Servier, and Teva. JC reports research grants from AbbVie, Daiichi Sankyo, Novartis, Sun Pharma, and Pfizer; consulting fees from AbbVie, Bio-Path, Daiichi Sankyo, Gilead, Forma Therapeutics, Novartis, Pfizer, and Takeda; payment for lectures from Novartis, Pfizer, and Takeda; and has stock options with Bio-Path. AEP reports research grants from AbbVie, Actinium Pharmaceuticals, Astellas, Bayer, BioMed Valley Discoveries, and Daiichi Sankyo; personal fees from Actinium Pharmaceuticals, Agios Pharmaceuticals, Astellas, Daiichi Sankyo, Forma Therapeutics, Jazz Pharmaceuticals, Leukemia & Lymphoma Society (Beat AML Master Clinical Trial), Loxo Oncology, NewLink Genetics, Novartis, and Takeda; and non-financial support from Arog Pharmaceuticals, Astellas, Jazz Pharmaceuticals, NewLink Genetics, Novartis, and Takeda. MAS reports consulting fees from Bristol Myers Squibb, Kurome Therapeutics, and Novartis; and has stock options with Kurome Therapeutics. HD reports personal fees from Incyte and Servier. JW reports payment for participation on an advisory board from Abbvie and for participation on a data safety monitoring committee from AstraZeneca. MJL reports research grants from Astellas and FujiFilm Pharmaceuticals; consulting fees from AbbVie, Amgen, Bristol Myers Squibb, Daiichi Sankyo, Jazz Pharmaceuticals, Menarini, Pfizer, and Takeda; and payment for lectures from Astellas. RFS reports consulting fees from Daiichi Sankyo for participation on a steering committee and from AbbVie, Jazz Pharmaceuticals, and Pfizer for participation on advisory boards; payment for lectures from Daiichi Sankyo, Novartis, and Pfizer; is on a data safety monitoring board or advisory board for BerGenBio and Novartis; and has been provided with equipment by AbbVie, AstraZeneca, Boehringer Ingelheim, Daiichi Sankyo, PharmaMar, Pfizer, and Roche. TM, JH, YMK, JECR, LL, AB, and AL are employees of Daiichi Sankyo. All other authors declare no competing interests., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

The fms-like tyrosine kinase 3 (FLT3) inhibitor gilteritinib improved the survival of patients with relapsed or refractory (R/R) FLT3-mutated acute myelogenous leukemia (AML) in the phase 3 ADMIRAL trial. In this study, we assessed survival and relapse rates of patients in the ADMIRAL trial who underwent hematopoietic stem cell transplantation (HSCT), as well as safety outcomes in patients who received post-transplantation gilteritinib maintenance therapy. ADMIRAL was a global phase 3 randomized controlled trial that enrolled adult patients with FLT3-mutated R/R AML. Patients with R/R AML who harbored FLT3 internal tandem duplication mutations in the juxtamembrane domain or D835/I836 point mutations in the tyrosine kinase domain were randomized (2:1) to gilteritinib (120 mg/day) or to preselected high- or low-intensity salvage chemotherapy (1 or 2 cycles). Patients in the gilteritinib arm who proceeded to HSCT could receive post-transplantation gilteritinib maintenance therapy if they were within 30 to 90 days post-transplantation and had achieved composite complete remission (CRc) with successful engraftment and no post-transplantation complications. Adverse events (AEs) during HSCT were recorded in the gilteritinib arm only. Survival outcomes and the cumulative incidence of relapse were assessed in patients who underwent HSCT during the trial. Treatment-emergent AEs were evaluated in patients who restarted gilteritinib as post-transplantation maintenance therapy. Patients in the gilteritinib arm underwent HSCT more frequently than those in the chemotherapy arm (26% [n = 64] versus 15% [n = 19]). For all transplantation recipients, 12- and 24-month overall survival (OS) rates were 68% and 47%, respectively. Despite a trend toward longer OS after pretransplantation CRc, post-transplantation survival was comparable in the 2 arms. Patients who resumed gilteritinib after HSCT had a low relapse rate after pretransplantation CRc (20%) or CR (0%). The most common AEs observed with post-transplantation gilteritinib therapy were increased alanine aminotransferase level (45%), pyrexia (43%), and diarrhea (40%); grade ≥3 AEs were related primarily to myelosuppression. The incidences of grade ≥III acute graft-versus-host disease and related mortality were low. Post-transplantation survival was similar across the 2 study arms in the ADMIRAL trial, but higher remission rates with gilteritinib facilitated receipt of HSCT. Gilteritinib as post-transplantation maintenance therapy had a stable safety and tolerability profile and was associated with low relapse rates. Taken together, these data support a preference for bridging therapy with gilteritinib over chemotherapy in transplantation-eligible patients., (Copyright © 2022 The American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc. All rights reserved.)

Patients with refractory or relapsed and refractory myeloid malignancies have a poor prognosis. Allogeneic hematopoietic cell transplantation (HCT) with myeloablative conditioning (MAC) in patients with active, chemotherapy-refractory myeloid disease is historically associated with high rates of relapse and nonrelapse mortality (NRM). A MAC regimen combining clofarabine with busulfan (Clo/Bu4) has been reported to exhibit antileukemic activity with acceptable toxicity in patients age ≤70 years. Here we describe the clinical outcomes of a real-world population of patients with active myeloid malignancies undergoing allogeneic HCT with Clo/Bu4 MAC. In a single-center retrospective descriptive analysis, we identified patients who underwent HCT for myeloid malignancies not in remission using Clo/Bu4 MAC between 2012 and 2020. We report event-free survival (EFS) and overall survival (OS), cumulative incidences of relapse and NRM, and the incidence and severity of acute and chronic graft-versus-host disease (GVHD). We identified 69 patients with a median age of 60 years (range, 22 to 70 years). Most patients had relapsed/refractory or primary refractory acute myelogenous leukemia (AML; n = 55) or refractory myelodysplastic syndrome (MDS; n = 12); 1 patient had chronic myelogenous leukemia, and 1 patient had a blastic plasmacytoid dendritic cell neoplasm. Fifty patients (72.5%) had complete remission at day 100 post-transplantation. Two-year EFS and OS were 30% (95% confidence interval [CI], 20% to 44%) and 40% (95% CI, 29% to 54%), respectively. Patients with AML had a 2-year EFS and OS of 28% (95% CI, 18% to 44%) and 38% (95% CI, 27% to 54%), respectively; those with MDS had a 2-year EFS and OS of 47% (95% CI, 25% to 88%) and 56% (95% CI, 33% to 94%), respectively. The cumulative incidence of relapse at 2 years was 39% (95% CI, 27% to 51%) for all patients, including 45% (95% CI, 31% to 58%) in the patients with AML and 18% (95% CI, 2% to 45%) in those with MDS. NRM at 2 years was 31% (95% CI, 20% to 42%), including 27% (95% CI, 15% to 39%) in patients with AML and 35% (95% CI, 10% to 63%) in those with MDS. The total incidence of acute GVHD (aGVHD) of any severity was 80%, and the incidence of grade III-IV aGVHD was 22%. In patients who achieved remission, those who required systemic immunosuppression for aGVHD (58%) had poorer 2-year EFS (29% versus 54%; P = .05) and 2-year OS (39% versus 70%; P = .04) compared to those who did not. The 2-year cumulative incidence of chronic GVHD was 44% (95% CI, 28% to 58%). Clo/Bu4 MAC followed by allogeneic HCT for patients with active myeloid malignancies is an effective transplantation strategy for patients up to age 70, particularly those with advanced MDS. The high incidence of and poor outcomes associated with aGVHD highlight the importance of optimizing preventative strategies., Competing Interests: Declaration of Competing Interest There are no conflicts of interest to report., (Copyright © 2022 The American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc. All rights reserved.)

Purpose: The FMS-related tyrosine kinase 3 (FLT3) inhibitor gilteritinib is standard therapy for relapsed/refractory FLT3 -mutated ( FLT3 mut ) acute myeloid leukemia (AML) but seldom reduces FLT3 mut burden or induces sustained efficacy. Gilteritinib combines synergistically with the BCL-2 inhibitor venetoclax in preclinical models of FLT3 mut AML., Methods: This phase Ib open-label, dose-escalation/dose-expansion study (ClinicalTrials.gov identifier: NCT03625505) enrolled patients with FLT3 wild-type and FLT3 mut (escalation) or FLT3 mut (expansion) relapsed/refractory AML. Patients received 400 mg oral venetoclax once daily and 80 mg or 120 mg oral gilteritinib once daily. The primary objectives were safety, identification of the recommended phase II dose, and the modified composite complete response (mCRc) rate (complete response [CR] + CR with incomplete blood count recovery + CR with incomplete platelet recovery + morphologic leukemia-free state) using ADMIRAL phase III-defined response criteria., Results: Sixty-one patients were enrolled (n = 56 FLT3 mut ); 64% (n = 36 of 56) of FLT3 mut patients had received prior FLT3 inhibitor therapy. The recommended phase II dose was 400 mg venetoclax once daily and 120 mg gilteritinib once daily. The most common grade 3/4 adverse events were cytopenias (n = 49; 80%). Adverse events prompted venetoclax and gilteritinib dose interruptions in 51% and 48%, respectively. The mCRc rate for FLT3 mut patients was 75% (CR, 18%; CR with incomplete blood count recovery, 4%; CR with incomplete platelet recovery, 18%; and morphologic leukemia-free state, 36%) and was similar among patients with or without prior FLT3 inhibitor therapy (80% v 67%, respectively). The median follow-up was 17.5 months. The median time to response was 0.9 months, and the median remission duration was 4.9 months (95% CI, 3.4 to 6.6). FLT3 molecular response (< 10 -2 ) was achieved in 60% of evaluable mCRc patients (n = 15 of 25). The median overall survival for FLT3 mut patients was 10.0 months., Conclusion: The combination of venetoclax and gilteritinib was associated with high mCRc and FLT3 molecular response rates regardless of prior FLT3 inhibitor exposure. Dose interruptions were needed to mitigate myelosuppression.

Patients undergoing haploidentical or mismatched unrelated donor (haplo/MMUD) allogeneic hematopoietic cell transplantation (alloHCT) receiving post-transplant cyclophosphamide (PTCy) are at high risk of cytomegalovirus (CMV) infection. Experience with letermovir (LET) in this population is limited. This single center retrospective cohort study compared CMV and transplant outcomes between LET and a historical control with high-dose valacyclovir (HDV) prophylaxis in adults undergoing haplo/MMUD alloHCT. Thirty-eight CMV seropositive patients were included, 19 in each arm. LET reduced the incidence of CMV infection (5% vs. 53%, RR 0.01, 95% CI 0.014-0.71, p  = .001) and need for CMV treatment by day +100 (5% vs. 37%, RR 0.14, 95% CI 0.18-0.99, p  = .017) compared to HDV. Median CMV event-free-survival was improved with LET (not reached vs. 80 days, HR 0.114, 95% CI 0.07-0.61, p  = .004). These data support the efficacy of LET in alternative donor transplants.

CPX-351 and venetoclax and azacitidine (ven/aza) are both indicated as initial therapy for acute myeloid leukemia (AML) in older adults. In the absence of prospective randomized comparisons of these regimens, we used retrospective observational data to evaluate various outcomes for patients with newly diagnosed AML receiving either CPX-351 (n = 217) or ven/aza (n = 439). This study used both a nationwide electronic health record (EHR)-derived de-identified database and the University of Pennsylvania EHR. Our study includes 217 patients who received CPX-351 and 439 who received ven/aza. Paitents receiving ven/aza were older, more likely to be treated in the community, and more likely to have a diagnosis of de novo acute myeloid leukemia. Other baseline covariates were not statistically significantly different between the groups. Median overall survival (OS) for all patients was 12 months and did not differ based on therapy (13 months for CPX-351 vs 11 months for ven/aza; hazard ratio, 0.88; 95% confidence interval, 0.71-1.08; P = .22). OS was similar across multiple sensitivity analyses. Regarding safety outcomes, early mortality was similar (10% vs 13% at 60 days). However, documented infections were higher with CPX-351 as were rates of febrile neutropenia. Hospital length of stay, including any admission before the next cycle of therapy, was more than twice as long for CPX-351. In this large multicenter real-world dataset, there was no statistically significant difference in OS. Prospective randomized studies with careful attention to side effects, quality of life, and impact on transplant outcomes are needed in these populations., (© 2022 by The American Society of Hematology. Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0), permitting only noncommercial, nonderivative use with attribution. All other rights reserved.)

Limited treatment options exist for patients with relapsed/refractory (R/R) acute myeloid leukemia (AML). Venetoclax (VEN) in combination with a hypomethylating agent (HMA) or low-dose cytarabine (LDAC) has been recently approved for treatment-naïve patients unfit for intensive induction. Limited data are available to characterize the efficacy of VEN combinations in R/R AML. We retrospectively analyzed 77 patients with a median of 1 prior therapy (range 0-5) treated with VEN combinations for R/R AML or AML secondary to myelodysplastic syndrome (MDS) progressing after HMA monotherapy. The median overall survival (OS) was 13.1 months (95% CI 9.2-15.1). The median progression-free survival (PFS) was 12 months (95% CI 8.2-15.4) with a median duration of response of 8.9 months (95% CI 5.7-13.9). Overall response rate (ORR) was 68% with a composite complete response (CR) and CR with incomplete hematologic recovery (CRi) rate of 53%. VEN combination therapy is efficacious in R/R AML and further prospective studies are warranted.

Competing Interests: Alexander E. PerlHonoraria: Astellas Pharma, Daiichi SankyoConsulting or Advisory Role: Astellas Pharma, Actinium Pharmaceuticals, Daiichi Sankyo, AbbVie, FORMA Therapeutics, Sumitomo Dainippon, Celgene/Bristol Myers Squibb, Syndax, Genentech, BerGenBio, ImmunogenResearch Funding: Astellas Pharma (Inst), Bayer (Inst), Daiichi Sankyo (Inst), Fujifilm (Inst), AbbVie (Inst), Syndax (Inst)No other potential conflicts of interest were reported.

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., (© 2022 by The American Society of Hematology.)

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.

The fms-like tyrosine kinase 3 (FLT3) inhibitor gilteritinib is indicated for relapsed or refractory (R/R) FLT3-mutated acute myeloid leukemia (AML), based on its observed superior response and survival outcomes compared with salvage chemotherapy (SC). Frontline use of FLT3 tyrosine kinase inhibitors (TKIs) midostaurin and sorafenib may contribute to cross-resistance to single-agent gilteritinib in the R/R AML setting but has not been well characterized. To clarify the potential clinical impact of prior TKI use, we retrospectively compared clinical outcomes in patients with R/R FLT3-mutated AML in the CHRYSALIS and ADMIRAL trials who received prior midostaurin or sorafenib against those without prior FLT3 TKI exposure. Similarly high rates of composite complete remission (CRc) were observed in patients who received a FLT3 TKI before gilteritinib (CHRYSALIS, 42%; ADMIRAL, 52%) and those without prior FLT3 TKI therapy (CHRYSALIS, 43%; ADMIRAL, 55%). Among patients who received a prior FLT3 TKI in ADMIRAL, a higher CRc rate (52%) and trend toward longer median overall survival was observed in the gilteritinib arm versus the SC arm (CRc = 20%; overall survival, 5.1 months; HR = 0.602; 95% CI: 0.299, 1.210). Remission duration was shorter with prior FLT3 TKI exposure. These findings support gilteritinib for FLT3-mutated R/R AML after prior sorafenib or midostaurin., (© 2022. The Author(s).)

The phase 3 Study of ASP2215 Versus Salvage Chemotherapy in Patients With Relapsed or Refractory Acute Myeloid Leukemia (AML) With FMS-like Tyrosine Kinase (FLT3) Mutation (ADMIRAL) trial demonstrated the superiority of the FLT3 inhibitor, gilteritinib, to salvage chemotherapy (SC) in patients with FLT3-mutated relapsed or refractory (R/R) AML. Baseline comutations, FLT3-internal tandem duplication (ITD) allelic ratio and length, and treatment-emergent mutations were analyzed in patients in the ADMIRAL trial. Baseline comutations were grouped according to gene subgroups (DNA methylation/hydroxymethylation, transcription, chromatin-spliceosome, receptor tyrosine kinase-Ras signaling, TP53-aneuploidy, NPM1, DNMT3A, DNMT3A/NPM1, WT-1, and IDH1/IDH2). Across all but 1 gene subgroup (TP53-aneuploidy), higher pretransplant response rates and a trend toward longer overall survival were observed with gilteritinib vs SC. Patients with DNMT3A/NPM1 comutations who received gilteritinib had the most favorable outcomes of any molecular subgroup analyzed. Survival outcomes with gilteritinib were not adversely affected by FLT3-ITD allelic ratio, FLT3-ITD length, or multiple FLT3-ITD mutations. Among patients who relapsed on gilteritinib, Ras/mitogen-activated protein kinase (MAPK) pathway and FLT3 F691L gene mutations were the most common mutational events associated with treatment resistance. However, the occurrence of Ras/MAPK pathway gene mutations at baseline did not preclude a clinical benefit from gilteritinib. Acquisition of multiple Ras/MAPK pathway gene mutations at relapse suggests a high level of pathway reactivation is needed to overcome the gilteritinib treatment effect. These findings provide insight into the R/R AML molecular profile and the impact of FLT3 inhibitors on mutational evolution associated with treatment resistance and benefit of gilteritinib across a wide spectrum of molecular and genetic subgroups in FLT3-mutated R/R AML. This trial was registered at www.clinicaltrials.gov as #NCT02421939., (© 2022 by The American Society of Hematology. Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0), permitting only noncommercial, nonderivative use with attribution. All other rights reserved.)

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 is approved for the treatment of relapsed/refractory (R/R) acute myeloid leukemia (AML) with an FLT3-mutation (FLT3 mut+ ). 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 FLT3 mut+ AML. The composite complete remission (CR) rate (CRc, defined as CR + CR i  + 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., (© 2022 Wiley Periodicals LLC.)

Abstract: Therapeutic outcomes for acute myeloid leukemia patients with Fms-like tyrosine kinase 3 (FLT3) mutations have improved substantially since the discovery of small molecule tyrosine kinase inhibitors. Today, use of FLT3 inhibitors is standard in frontline intensive chemotherapy as well as patients with relapsed or refractory acute myeloid leukemia and FLT3 mutations and increasingly used as for prolonged remission maintenance posttransplant and/or postconsolidation. Yet, FLT3 inhibitors alone are not curative, and best outcomes are seen when the drugs are used as part of combination regimens. Optimizing therapy for patients with FLT3 mutations remains a work in progress. Overall, modern therapeutic approaches generate cure rates for this group at levels that argue against considering these mutations adverse risk. Still, such survivals require intensive therapy and often transplant. Therefore, efforts are underway to determine if lower toxicity regimens can attain comparable outcomes, at least for patients responding optimally. This review will review the various FLT3 inhibitors that are approved or in development, highlight the areas where they have been shown to add value, and identify areas where their use remains controversial., Competing Interests: Conflicts of Interest and Source of Funding: A.E.P. has received honoraria or consulting fees from AbbVie, Astellas, Daiichi Sankyo, Genentech, Novartis, and Arog and grants or research support (to institution) from AbbVie, Astellas, Daiichi Sankyo, Novartis, and FujiFilm. K.W.P. has received honoraria of consultancy fees from AbbVie, Astellas, Boston BioMedical, Bristol Myers Squibb, Novartis, Jazz Pharmaceuticals, and Celgene and institutional research funding from AbbVie, Astellas, Agios, Daiichi Sankyo, and Millennium., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Research has resulted in regulatory approval of nine agents for acute myeloid leukaemia indications by the US Food and Drug Administration since 2017: the Bcl-2 inhibitor, venetoclax; two FLT3 inhibitors, midostaurin and gilteritinib; two IDH inhibitors, ivosidenib (IDH1 inhibitor) and enasidenib (IDH2 inhibitor); the anti-CD33 antibody-drug conjugate, gemtuzumab ozogamicin; the oral, poorly absorbable hypomethylating agent, azacitidine; the liposomal formulation of cytarabine and daunorubicin (5:1 ratio), CPX-351; and the hedgehog signalling pathway inhibitor, glasdegib. A 100% absorbable oral formulation of the hypomethylating agent decitabine was approved for the treatment of myelodysplastic syndrome and chronic myelomonocytic leukaemia, and might be used as an alternative to parenteral hypomethylating agents. Several of the approvals are as single-agent therapies or in specific combinations for narrow indications, thus offering poor treatment value. In this Review, we discuss ongoing research into combinations containing these commercially available targeted therapies for acute myeloid leukaemia., Competing Interests: Declaration of interests HK reports research grants and honoraria from AbbVie, Amgen, Ascentage, Bristol Myers Squibb, Daiichi-Sankyo, Immunogen, Jazz Pharmaceuticals, Novartis, Pfizer, and Sanofi, and honoraria from Actinium (Advisory Board), Adaptive Biotechnologies, Aptitude Health, BioAscend, Delta Fly, Janssen Global, Oxford Biomedical, and Takeda Oncology. AW has served on advisory boards for Novartis, Janssen, Amgen, Roche, Pfizer, AbbVie, Servier, Celgene (Bristol Myers Squibb), Macrogenics, Agios, and Gilead Sciences, receives research funding from Novartis, AbbVie, Servier, Celgene (Bristol Myers Squibb), AstraZeneca, and Amgen, serves on speakers bureaus for AbbVie, Novartis, and Celgene, and receives royalty payments from the Walter and Eliza Hall Institute of Medical Research related to venetoclax. MT has served on advisory boards for AbbVie, Daiichi-Sankyo, Orsenix, Kahr, Delta Fly Pharma, Jazz Pharmaceuticals, Roche, Biosight, Novartis, Innate Pharmaceuticals, Kura Oncology, and Syros Pharmaceuticals, received research funding from AbbVie, Orsenix, Biosight, Glycomimetics, Rafael Pharmaceuticals, and Amgen, and received royalty from UpToDate. NJS has received consulting fees from Takeda Oncology and AstraZeneca, research funding from Takeda Oncology and Astellas Pharma, and honoraria from Amgen. ESW has served on advisory boards for AbbVie, Astellas, Celgene (Bristol Myers Squibb), Genentech, GlaxoSmithKline, Jazz Pharmaceuticals, Kite Pharmaceuticals, Kura Oncology, Novartis, Pfizer, Stemline, and Takeda, provided consulting for Mana Therapeutics, served as a speaker for Stemline, Kura Oncology, Pfizer, and Dava Oncology, and served on data safety monitoring committees for AbbVie and Rafael Pharmaceuticals. CDiN received research funding from AbbVie, Agios, Calithera, Cleave, Celgene (Bristol Myers Squibb), Daiichi-Sankyo, Forma, ImmuneOnc, and Loxo, consultancy fees from AbbVie, Agios, Aprea, Celgene/Bristol Myers Squibb, ImmuneOnc, and advisory board fees from Novartis, Aprea and Takeda. She is a scientific advisor with stock options from Notable Labs. AEP received research funding from AbbVie, Actinium Pharmaceuticals, Astellas, Daiichi-Sankyo, and FujiFilm, and received consultancy or advisory fees from AbbVie, Actinium Pharmaceuticals, Astellas, Celgene (Bristol Myers Squibb), Genentech, Daiichi-Sankyo, Loxo, Syndax, Sumitomo Dainippon, Forma, and Onconova. EMS received research funding from Agios, Celgene, Bristol Myers Squibb, Syndax, Syros, Bayer, and Biotheryx, and has served in a consulting or advisory role fees for Daiichi-Sankyo, Bristol Myers Squibb, Celgene, Agios, Novartis, AbbVie, Astellas, Genentech, Syndax, Gilead Sciences, Amgen, Foghorn, Neoleukin, Pinotbio, and Blueprint. ND has received research funding from Daiichi-Sankyo, Bristol Myers Squibb, Pfizer, Gilead Sciences, Sevier, Genentech, Astellas, AbbVie, Hanmi, Trovagene, Fate Therapeutics, Amgen, Novimmune, Glycomimetics, Trillium, and ImmunoGen, and has served in a consulting or advisory role for Daiichi-Sankyo, Bristol Myers Squibb, Arog, Pfizer, Novartis, Jazz Pharmaceuticals, Celgene, AbbVie, Astellas, Genentech, Immunogen, Servier, Syndax, Trillium, Gilead Sciences, Amgen, Shattuck Labs, and Agios. We declare no other competing interests., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Pericarditis is an uncommon cardiac complication following allogeneic hematopoietic cell transplantation (alloHCT), with limited data characterizing its incidence, presentation, and management. The etiology of pericarditis in this setting is poorly understood and may include conditioning-related toxicity, infection, or graft-versus-host disease (GVHD). The objective of the present study was to characterize the clinical presentation, management, and outcomes of post-alloHCT pericarditis observed at a single center. This retrospective case-control study of consecutive adults undergoing alloHCT over 5 years was conducted to identify patients who developed pericarditis. Pericarditis was diagnosed using clinical, electrocardiography, and echocardiography findings. Identified cases were compared with a cohort of patients who underwent alloHCT during the same period but did not develop pericarditis. A total of 620 patients underwent alloHCT over the 5-year period, 20 of whom developed pericarditis (3.2% incidence). One patient had a pre-alloHCT history of pericarditis. All but 3 patients had received anthracycline therapy and 1 patient had received chest irradiation before undergoing alloHCT. Patients with pericarditis were more likely than patients without pericarditis to have received total body irradiation (odds ratio [OR], 4.57; P = .003) or cyclophosphamide (OR, 2.35; P = .07) as conditioning or GVHD prophylaxis. Fourteen patients experienced their initial episode of pericarditis before day +100 post-alloHCT, with a median time to onset at day +7. Six patients had their initial episode on day +100 or later, with a median time to onset at day +268. Only 1 patient had active, previously diagnosed GVHD, and 3 patients were on systemic steroid therapy at the time of pericarditis diagnosis. Pericarditis was treated primarily with colchicine (median duration 91 days). Seven episodes of recurrence occurred in 5 patients. Two patients experienced cardiac tamponade following their initial diagnosis, and 3 developed tamponade at recurrence. Recurrence was more common in patients who received no or <90 days of colchicine compared with those who received ≥90 days (45.5% vs 0%; P = .02). No cardiac-related deaths occurred. Overall survival was 85% at a median follow-up of 30 months post-alloHCT. Pericarditis occurred in 3.2% of patients in this single-center study, with cases observed both before and after day +100 and some cases occurring ≥1 year after alloHCT. Colchicine was an effective intervention, with ≥90 days of treatment associated with reduced recurrence. Pericarditis should be considered in patients presenting with chest pain following alloHCT., (Copyright © 2021 The American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc. All rights reserved.)

Gingival myeloid sarcoma (MS) refractory to induction chemotherapy is a rare clinical entity and can be treated with palliative radiation therapy (RT). However, there are few previously published reports of RT approaches for the treatment of gingival MS. We present a single institution retrospective observational study of adult patients treated with palliative RT for chemotherapy refractory gingival MS. A total of six patients diagnosed with gingival MS in the setting of relapsed or refractory acute myeloid leukemia treated with palliative RT were identified, with a median age of 66 (range 52-77). Patients were treated with radiation doses ranging from 5 to 20 Gy in 2-10 fractions. Two patients had adequate follow-up time to assess treatment response. One patient who was simulated with PET/CT experienced a local complete response, while the other patient required retreatment 2 months after initial treatment and experienced an eventual local partial response. Three patients experienced radiation mucositis, with one patient experiencing grade 5 toxicity attributed to concomitant treatment with the radiosensitizer hydroxyurea. We believe that this study can provide a practical reference point for other clinicians given the rarity of gingival MS requiring palliative radiation therapy as a clinical entity., Competing Interests: AP has been a consultant for and received research funding from Astellas Pharma outside this study. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Lee, Baron, Wright, Plastaras, Perl and Paydar.)

Oropharyngeal mucositis (OPM) is common following conditioning for allogeneic hematopoietic cell transplantation (alloHCT) and results in pain, functional status decline, need for nutritional support, infections, and prolonged length of stay (LOS). Methotrexate (MTX) graft-versus-host disease (GVHD) prophylaxis exacerbates OPM and slows hematopoietic engraftment, which may prolong LOS. Previous studies have demonstrated reduced OPM and more rapid engraftment when leucovorin (LCV) is added following MTX GVHD prophylaxis, yet this practice is controversial. The primary objective of this study was to determine if the routine addition of LCV to MTX GVHD prophylaxis impacted the duration of grade 2 to 4 OPM. Secondary objectives included determination of the incidence of grade 2 to 4 and grade 3 to 4 OPM, time to engraftment, ability to receive all four planned MTX doses, use of total parenteral nutrition (TPN), use of patient-controlled analgesia (PCA), LOS, incidence of acute or chronic GVHD, relapse-free survival (RFS), and overall survival (OS). This single-center, retrospective cohort study compared alloHCT outcomes for 46 adult patients who received MTX 15 mg/m 2 day +1; MTX 10 mg/m 2 days +3, +6, and +11 (15-10-10-10); and LCV following days +3, +6, and +11 MTX compared to historical controls who did not. Patients who received myeloablative conditioning (MAC) and matched related donor (MRD) or matched unrelated donor (MUD) alloHCT were included. The addition of LCV resulted in significant reductions in the duration of grade 2 to 4 OPM (median, 6 days versus 10.5 days; P = .0004), duration of TPN (7 days versus 16 days; P = .001), PCA use (16% versus 39%; P = .0001), time to neutrophil engraftment (median, 18 versus 20 days; P = .008), and LOS (median, 27.5 versus 31 days; P = .017) compared to historical controls. Patients who received routine LCV had similar incidences of grade 2 to 4 acute GVHD (30% versus 28%; relative risk [RR], 1.08; 95% confidence interval [CI], .57 to 2.03; P = 1.0), grade 3 or 4 acute GVHD (2% versus 7%; RR, .33; 95% CI, .04 to 3.09; P = .62) and chronic GVHD (37% versus 30%; RR, 1.21; 95% CI, .67 to 2.16; P = .66) compared to historical controls. Graft failure occurred in 2% of patients in each group. In a multivariable logistic regression analysis, RFS was similar in the LCV group compared to historical controls (HR, .86; 95% CI, .24 to 1.2; P = .13); however, OS was improved in patients who received LCV (HR, .33; 95% CI, .13 to .83; P = .01). In patients undergoing MAC MRD/MUD alloHCT with four planned doses of MTX GVHD prophylaxis (15-10-10-10), LCV was associated with reduced duration of grade 2 to 4 OPM, faster neutrophil engraftment, reduced utilization of TPN and PCA, and shortened LOS compared to historical controls not receiving routine LCV. These benefits were apparent without an increased risk of acute or chronic GVHD or adverse effect on RFS. LCV improved OS; however, it is unclear if this was due to the intervention or an unmeasured confounder. A randomized, prospective trial of LCV prophylaxis in patients receiving MAC alloHCT and MTX 15-10-10-10 GVHD prophylaxis is warranted to confirm our findings., (Copyright © 2021 The American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc. All rights reserved.)

New drug approvals now afford AML physicians a wider choice of initial treatment options than ever before. Although chemotherapy for AML is by no means ready to be replaced entirely by novel agents, the role of traditional cytotoxics in AML therapy is rapidly changing. In particular, biologically targeted agents such as the BCL2 inhibitor venetoclax and inhibitors of FLT3 and IDH mutations stand out as drugs likely to take AML therapy in important new directions. Maximum response and survival benefits likely require combinations of novel agents and chemotherapy or multiple novel agents together. The recently-published phase 3 VIALE-A study demonstrates a very successful example of a new combination approach, which led to venetoclax plus azacitidine establishing itself as the new standard of care for patients unfit for intensive chemotherapy. One could reasonably expect other subsets of AML to benefit from this regimen or other applications of venetoclax combinations. Building on this experience, venetoclax-based regimens also have the potential to replace standard intensive cytarabine/anthracycline "7&3" induction approach for some if not many patients who are fit for induction. This review will describe novel agents with the greatest potential for impactful frontline applications that will change the AML treatment paradigm., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Despite the substantial clinical activity of fms-related tyrosine kinase 3 (FLT3) inhibitors in relapsed or refractory (R/R) FLT3-ITD‒positive acute myelogenous leukemia (AML), durable remissions and prolonged survival in this population require allogeneic hematopoietic stem cell transplantation (allo-HSCT). Quizartinib, a once-daily oral, highly potent, and selective FLT3 inhibitor, significantly prolonged overall survival (OS) and improved clinical benefit compared with salvage chemotherapy (median OS, 6.2 months versus 4.7 months; hazard ratio [HR], .76; 95% confidence interval [CI], .58 to .98; P = .018; composite complete remission [CRc] rate, 48% versus 27%; median duration of CRc, 2.8 months versus 1.2 months; mortality rate, .8% versus 14% by day 30, 7% versus 24% by day 60) in patients with R/R FLT3-ITD AML in the phase 3 QuANTUM-R trial. In this post hoc analysis, we described the characteristics of and clinical outcomes in patients who underwent on-study HSCT in QuANTUM-R at the investigator's discretion and institutional practices. Of 367 randomized patients, 78 (32%) in the quizartinib arm and 14 (11%) in the salvage chemotherapy arm underwent on-study allo-HSCT without any intervening therapy for AML after quizartinib or study-specified salvage chemotherapy. Pooled data of patients from both treatment arms showed a longer median overall survival (OS) in transplant recipients versus those treated without allo-HSCT (12.2 months versus 4.4 months; HR, .315; 95% CI, .233 to .427). Pooled data also showed a longer median OS in patients with a last recorded response of CRc before allo-HSCT versus patients without a CRc (20.1 months versus 8.8 months; HR, .506; 95% CI, .296 to .864). By treatment arm, the median OS was 25.1 months with quizartinib and 20.1 months with salvage chemotherapy in patients with a last recorded response of CRc before allo-HSCT. Forty-eight patients in the quizartinib arm continued quizartinib treatment after allo-HSCT. In the 31 patients with a last recorded response of CRc before allo-HSCT who continued quizartinib after allo-HSCT, the median OS was 27.1 months. Continuation of quizartinib after allo-HSCT was tolerable, and no new safety signals were identified. These results suggest that post-transplantation survival following salvage chemotherapy and quizartinib treatment are similar. However, quizartinib response occurs more frequently than with salvage chemotherapy, potentially allowing more patients to undergo transplantation and achieve durable clinical benefit. In addition, post-transplant quizartinib was found to be tolerable and may be associated with prolonged survival in some patients, highlighting its potential value in the management of patients with FLT3-ITD R/R AML., (Copyright © 2020 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc. All rights reserved.)

The FLT3 inhibitor gilteritinib has clinical activity in patients with FLT3-mutated (FLT3 mut+ ) relapsed/refractory (R/R) acute myeloid leukemia (AML). The impact of FLT3 mutation clearance and the achievement of composite complete remission (CRc) and complete remission/complete remission with partial hematologic recovery (CR/CRh) on overall survival (OS) in patients with FLT3 mut+ R/R AML treated with single-agent gilteritinib in a phase 1/2 trial were evaluated. Using next-generation sequencing, a FLT3-ITD variant allele frequency of ≤10 -4 was used to define FLT3-ITD clearance in patients with no morphologic leukemia (ie, CRc). A total of 108 patients with FLT3-ITD-positive (FLT3-ITD+) R/R AML were analyzed; 95 of these patients had received ≥80-mg/day gilteritinib. Ten of the 95 patients had FLT3-ITD clearance; eight of these 10 patients achieved CRc and were considered negative for measurable residual disease. There was a trend toward longer OS in patients who attained CRc with FLT3-ITD clearance (131.4 weeks) versus those who achieved CRc and did not have FLT3-ITD clearance (n = 41; 43.3 weeks; HR = 0.416; p = 0.066). Among patients treated with ≥80-mg/day gilteritinib who achieved CR/CRh (n = 24), seven had FLT3-ITD clearance. Among patients who received 120-mg/day gilteritinib, those who achieved CR/CRh had a longer median OS (70.6 weeks) and higher 52-week survival probability (66.7%) than patients who did not achieve CR/CRh (n = 71; median OS, 41.7 weeks; 52-week survival probability, 20.2%). Overall, these data suggest that gilteritinib can induce deep molecular responses in patients with FLT3-ITD+ R/R AML, and in the setting of CRc or CR/CRh, these responses may be associated with prolonged survival., (© 2020 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.)

Approval of midostaurin, a multikinase inhibitor, in combination with chemotherapy for the treatment of adults with newly diagnosed FLT3 mutation-positive acute myeloid leukemia, was based on the phase 3 RATIFY trial results. RADIUS-X (NCT02624570) was an expanded access program providing access to midostaurin during regulatory review and extending the understanding of the safety and tolerability of midostaurin. Patients aged ≥18 years received midostaurin with 1-2 cycles of induction therapy (cytarabine plus daunorubicin or idarubicin) and ≤4 cycles of high-dose cytarabine consolidation chemotherapy or as single-agent maintenance therapy. The study enrolled 103 patients. No new safety events were observed; toxicities were not influenced by age, anthracycline choice, or coadministration of CYP3A4 inhibitors. The most common adverse events (AEs) were febrile neutropenia, nausea, and diarrhea. During maintenance, 46% of patients reported AEs. Midostaurin demonstrated a manageable safety profile and was associated with high transplant and low on-treatment relapse rates.

The mutant IDH1 (mIDH1) inhibitor BAY1436032 demonstrated robust activity in preclinical AML models, supporting clinical evaluation. In the current dose-escalation study, BAY1436032 was orally administered to 27 mIDH1 AML subjects across 4 doses ranging from 300 to 1500 mg twice-daily. BAY1436032 exhibited a relatively short half-life and apparent non-linear pharmacokinetics after continuous dosing. Most subjects experienced only partial target inhibition as indicated by plasma R-2HG levels. BAY1436032 was safe and a maximum tolerated dose was not identified. The median treatment duration for all subjects was 3.0 months (0.49-8.5). The overall response rate was 15% (4/27; 1 CRp, 1 PR, 2 MLFS), with responding subjects experiencing a median treatment duration of 6.0 months (3.9-8.5) and robust R-2HG decreases. Thirty percent (8/27) achieved SD, with a median treatment duration of 5.5 months (3.1-7.0). Degree of R-2HG inhibition and clinical benefit did not correlate with dose. Although BAY1436032 was safe and modestly effective as monotherapy, the low overall response rate and incomplete target inhibition achieved at even the highest dose tested do not support further clinical development of this investigational agent in AML.

Background and Objective: Gilteritinib is a novel, highly selective tyrosine kinase inhibitor approved in the USA, Canada, Europe, Brazil, Korea, and Japan for the treatment of FLT3 mutation-positive acute myeloid leukemia. This article describes the clinical pharmacokinetic profile of gilteritinib., Methods: The pharmacokinetic profile of gilteritinib was assessed from five clinical studies., Results: Dose-proportional pharmacokinetics was observed following once-daily gilteritinib administration (dose range 20-450 mg). Median maximum concentration was reached 2-6 h following single and repeat dosing of gilteritinib; mean elimination half-life was 113 h. Elimination was primarily via feces. Exposure to gilteritinib was comparable under fasted and fed conditions. Gilteritinib is primarily metabolized via cytochrome P450 (CYP) 3A4; coadministration of gilteritinib with itraconazole (a strong P-glycoprotein inhibitor and CYP3A4 inhibitor) or rifampicin (a strong P-glycoprotein inducer and CYP3A inducer) significantly affected the gilteritinib pharmacokinetic profile. No clinically relevant interactions were observed when gilteritinib was coadministered with midazolam (a CYP3A4 substrate) or cephalexin (a multidrug and toxin extrusion 1 substrate). Unbound gilteritinib exposure was similar between subjects with hepatic impairment and normal hepatic function., Conclusions: Gilteritinib exhibits a dose-proportional pharmacokinetic profile in healthy subjects and in patients with relapsed/refractory acute myeloid leukemia. Gilteritinib exposure is not significantly affected by food. Moderate-to-strong CYP3A inhibitors demonstrated a significant effect on gilteritinib exposure. Coadministration of gilteritinib with CYP3A4 or multidrug and toxin extrusion 1 substrates did not impact substrate concentrations. Unbound gilteritinib was comparable between subjects with hepatic impairment and normal hepatic function; dose adjustment is not warranted for patients with hepatic impairment., Clinical Trial Registration: NCT02014558, NCT02456883, NCT02571816.

Pegaspargase (PEG) increases venous thromboembolism (VTE) in acute lymphoblastic leukemia (ALL) potentially due to depletion of anticoagulation factors, including antithrombin (AT). The benefit and cost of AT supplementation in adults is unclear. We aimed to characterize VTE incidence and risk factors following AT and determine the characteristics and costs of supplementation. Fifty-three adults received PEG and AT. VTE occurred in 21% (grade ≥3 8%). T cell ALL and patients receiving prednisone during induction were at highest risk. Repeat AT levels post supplementation were subtherapeutic forty-four percent of the time. A median of 18 days elapsed between PEG and two sequential therapeutic AT levels despite supplementation. Patients received a median of 2 AT doses per PEG dose at a median cost of $11,145. VTE remains common in adults despite AT supplementation. More aggressive AT supplementation may reduce VTE but warrant prospective evaluation given the significant cost.

Children and adults with Philadelphia chromosome-like B cell acute lymphoblastic leukemia (Ph-like B-ALL) experience high relapse rates despite best-available conventional chemotherapy. Ph-like ALL is driven by genetic alterations that activate constitutive cytokine receptor and kinase signaling, and early-phase trials are investigating the potential of the addition of tyrosine kinase inhibitors (TKIs) to chemotherapy to improve clinical outcomes. However, preclinical studies have shown that JAK or PI3K pathway inhibition is insufficient to eradicate the most common cytokine receptor-like factor 2-rearranged (CRLF2-rearranged) Ph-like ALL subset. We thus sought to define additional essential signaling pathways required in Ph-like leukemogenesis for improved therapeutic targeting. Herein, we describe an adaptive signaling plasticity of CRLF2-rearranged Ph-like ALL following selective TKI pressure, which occurs in the absence of genetic mutations. Interestingly, we observed that Ph-like ALL cells have activated SRC, ERK, and PI3K signaling consistent with activated B cell receptor (BCR) signaling, although they do not express cell surface μ-heavy chain (μHC). Combinatorial targeting of JAK/STAT, PI3K, and "BCR-like" signaling with multiple TKIs and/or dexamethasone prevented this signaling plasticity and induced complete cell death, demonstrating a more optimal and clinically pragmatic therapeutic strategy for CRLF2-rearranged Ph-like ALL.

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., (© 2020 Wiley Periodicals, Inc.)

FMS-like tyrosine kinase 3 (FLT3) tyrosine kinase inhibitors (TKIs) have activity in acute myeloid leukemia (AML) patients with FLT3 internal tandem duplication (ITD) mutations, but efficacy is limited by resistance-conferring kinase domain mutations. This phase 1/2 study evaluated the safety, tolerability, and efficacy of the oral FLT3 inhibitor PLX3397 (pexidartinib), which has activity against the FLT3 TKI-resistant F691L gatekeeper mutation in relapsed/refractory FLT3-ITD-mutant AML. Ninety patients were treated: 34 in dose escalation (part 1) and 56 in dose expansion (part 2). Doses of 800 to 5000 mg per day in divided doses were tested. No maximally tolerated dose was reached. Plasma inhibitory assay demonstrated that patients dosed with ≥3000 mg had sufficient levels of active drug in their trough plasma samples to achieve 95% inhibition of FLT3 phosphorylation in an FLT3-ITD AML cell line. Based on a plateau in drug exposure, the 3000-mg dose was chosen as the recommended phase 2 dose. The most frequently reported treatment-emergent adverse events were diarrhea (50%), fatigue (47%), and nausea (46%). Based on modified response criteria, the overall response rate to pexidartinib among all patients was 21%. Twenty-three percent of patients treated at ≥2000 mg responded. The overall composite complete response rate for the study was 11%. Six patients were successfully bridged to transplantation. Median overall survival (OS) of patients treated in dose expansion was 112 days (90% confidence interval [CI], 77-150 days), and median OS of responders with complete remission with or without recovery of blood counts was 265 days (90% CI, 170-422 days). This trial was registered at www.clinicaltrials.gov as #NCT01349049., (© 2020 by The American Society of Hematology.)

Since the discovery of FMS-like tyrosine kinase-3 (FLT3)-activating mutations as genetic drivers in acute myeloid leukemia (AML), investigators have tried to develop tyrosine kinase inhibitors that could effectively target FLT3 and alter the disease trajectory. Giltertinib (formerly known as ASP2215) is a novel compound that entered the field late, but moved through the developmental process with remarkable speed. In many ways, this drug's rapid development was facilitated by the large body of knowledge gained over the years from efforts to develop other FLT3 inhibitors. Single-agent gilteritinib, a potent and selective oral FLT3 inhibitor, improved the survival of patients with relapsed or refractory FLT3-mutated AML compared with standard chemotherapy. This continues to validate the approach of targeting FLT3 itself and establishes a new backbone for testing combination regimens. This review will frame the preclinical and clinical development of gilteritinib in the context of the lessons learned from its predecessors., (© 2020 by The American Society of Hematology.)

Gilteritinib is the first FMS-like tyrosine kinase 3 (FLT3) tyrosine kinase inhibitor (TKI) approved as monotherapy in acute myeloid leukemia with FLT3 internal tandem duplication and D835/I836 tyrosine kinase domain (TKD) mutations. Sequencing studies in patients have uncovered less common, noncanonical (NC) mutations in FLT3 and have implicated secondary TKD mutations in FLT3 TKI resistance. We report that gilteritinib is active against FLT3 NC and TKI resistance-causing mutations in vitro. A mutagenesis screen identified FLT3 F691L, Y693C/N, and G697S as mutations that confer moderate resistance to gilteritinib in vitro. Analysis of patients treated with gilteritinib revealed that 2/9 patients with preexisting NC FLT3 mutations responded and that secondary TKD mutations are acquired in a minority (5/31) of patients treated with gilteritinib. Four of 5 patients developed F691L mutations (all treated at <200 mg). These studies suggest that gilteritinib has broad activity against FLT3 mutations and limited vulnerability to resistance-causing FLT3 TKD mutations, particularly when used at higher doses., (© 2020 by The American Society of Hematology.)