Mutation-positive Acute Myeloid Leukemia Research Articles

RAD21 mutations in acute myeloid leukemia

The cohesin complex is a ring-shaped protein structure involved in DNA repair and chromosomal segregation. Studies have showed that genomic alterations in the cohesin complex members are among the initial occurrences in the development of acute myeloid leukemia (AML). STAG2 is the most commonly mutated and best-studied member of the cohesin complex in AML and mutations in this gene have been associated with adverse outcomes and are diagnostically relevant. However, the exact role of mutations in other members of the cohesin complex in the development of myeloid neoplasia is controversial. In this single institution study, we retrospectively reviewed data from the molecular profiles of 1,381 AML patients and identified 14 patients with mutations in RAD21, another member of the cohesin complex. We evaluated the frequency, mutational profile, clinico-pathologic features, and prognostic impact of RAD21 in this cohort. This study showed that RAD21-mutated AML often associates with monocytic differentiation, CD7 expression, co-existing mutations in epigenetic regulators, a normal karyotype, and poor prognosis. Our findings provide additional insights into the morphologic, immunophenotypic, and genomic profile of RAD21 mutation-positive AML and suggest that RAD21 mutations should be evaluated for independent prognostic significance in AML.

FLT3 Testing and Clonal Evolution in Patients with Acute Myeloid Leukemia: A Retrospective Cohort Study in Taiwan

INTRODUCTION: Mutation of the FMS-like tyrosine kinase 3 ( FLT3) gene is one of the most common genetic alterations in acute myeloid leukemia (AML), while FLT3 internal tandem duplication (ITD) is a predictor of poor disease prognosis in patients. Timing of FLT3 mutation testing and the pattern of FLT3 clonal evolution are critical issues for ensuring that patients with FLT3 mutation-positive AML receive targeted therapy promptly, but data from real-world clinical practice are limited. AIM: This retrospective cohort study aimed to assess the turnaround time of FLT3 testing in two patient cohorts with non-M3 primary AML: newly diagnosed (ND) patients and those with relapsed or refractory disease (R/R). A further aim in the R/R cohort was to assess the pattern of FLT3 clonal evolution. METHODS: Eligible adult patients had evidence of new diagnosis of AML or R/R AML between 1 January 2009 and 31 December 2019 and had undergone at least one FLT3 test at National Taiwan University Hospital. Patients were followed up until either the end of the data period, loss to follow up (no records for 6 months), or death. We analyzed the time from the date of ordering FLT3 test to receipt of results (both cohorts) and the acquisition (negative at diagnosis, positive at R/R), loss (positive at diagnosis, negative at R/R), or maintenance (no change in status) of FLT3 mutation at R/R compared with status at diagnosis. We also explored the association between acquisition/loss/maintenance of FLT3 mutation at R/R and overall survival (OS) in the R/R cohort. RESULTS: From a total AML dataset of 1,789 patients, 659 and 223 were included in the ND and R/R cohorts, respectively ( Table 1). Demographics and clinical characteristics of the ND and R/R cohorts were similar. The most common type of AML was recurrent genetic abnormalities in both ND and R/R cohorts (50.7% and 67.7%, respectively); 45.8% and 48.0% of patients, respectively, had a normal karyotype; and NPM1 (21.1% and 16.6%, respectively), and IDH1/ IDH2 (18.5% and 15.2%, respectively) were the most common types of co-mutations detected. There was no difference in the turnaround time of FLT3 testing between the ND and R/R cohorts ( Table 1). Since 2020, FLT3 testing protocols have been further optimized to meet a 7-day turnaround time; additionally, almost all chemotherapy-fit patients with FLT3 mutation receive midostaurin in combination with 3+7 chemotherapy after reimbursement of midostaurin was implemented in Taiwan in February 2020. Of 164 patients with FLT3 tests at both diagnosis and R/R, most (75.6%, n=124) were FLT3 mutation-negative at diagnosis ( Table 1). At R/R, 27/124 (21.8%) acquired an FLT3 mutation and 12/40 (30.0%) patients lost their FLT3 mutation ( Table 1). Risk of mortality was increased in patients who acquired an FLT3 mutation (HR [95% CI] 1.59 [0.97, 2.62]), maintained their FLT3 mutation (1.52 [0.58, 2.56]), or lost their FLT3 mutation (1.22 [0.58, 2.56]), compared with those who were FLT3-mutation negative at both diagnosis and R/R ( Figure 1). CONCLUSIONS: This study provided information on the real-world landscape of FLT3 testing among patients with AML in Taiwan. The turnaround time of FLT3 testing in the current study was longer than the time reported in clinical trials, likely owing to different procedures in sampling arrangement and report delivery between real world and clinical trial settings. The distribution of FLT3 mutation and pattern of clonal evolution were largely consistent with previously published clinical studies. The higher prevalence of FLT3 mutation in the R/R cohort versus the ND cohort is in accordance with previous research showing that FLT3-ITD mutation is predictive of relapse. Patients with FLT3 mutation at R/R had a shorter OS, which indicates the importance of FLT3 testing at R/R diagnosis to optimize outcomes through targeted therapy.

CPX-351 in FLT3-mutated acute myeloid leukemia.

CPX-351, a dual-drug liposomal encapsulation of daunorubicin and cytarabine in a 1:5 molar ratio, is approved for the treatment of newly diagnosed therapy-related acute myeloid leukemia (AML) or AML with myelodysplasia-related changes. In a pivotal phase III trial, CPX-351 significantly improved overall survival compared with standard-of-care 7 + 3 chemotherapy (7 days cytarabine; 3 days daunorubicin) in adults aged 60-75 years with newly diagnosed high-risk or secondary AML (median = 9.56 months vs. 5.95 months; hazard ratio = 0.69; 95% confidence interval = 0.52-0.90; p = 0.003). Approximately 30% of patients with newly diagnosed AML have mutations in the FLT3 gene, which may be associated with poor outcomes. Here, we review the current in vitro, clinical, and real-world evidence on the use of CPX-351 in patients with AML and mutations in FLT3. Additionally, we review preliminary data from clinical trials and patient case reports that suggest the combination of CPX-351 with FLT3 inhibitors may represent another treatment option for patients with FLT3 mutation-positive AML.

Bridging to transplant and post-transplant maintenance therapy with FLT3 inhibitors in patients with relapsed or refractory FLT3 mutated acute myeloid leukemia

ABSTRACTObjectives and MethodsThis single-center retrospective study was performed to evaluate the safety and efficacy of FMS-like tyrosine kinase 3 (FLT3) inhibitors before and after allogeneic hematopoietic cell transplantation (HCT) in relapsed/refractory patients with FLT3-mutation positive acute myeloid leukemia (AML).ResultsTen patients who met the eligibility criteria were included. Eight of them achieved hematological remission at HCT, within a median span of 79 days (range: 43–197). In post-HCT, patients started maintenance therapy (MT; median time-to-start 79 days, range: 43–197), and the median duration of MT was 390 days (range: 67–815). Grade 3 hematological adverse events (AEs) were found in two patients, and non-hematological AEs were found in five patients. Nine patients underwent either dose reduction, discontinuation of therapy, or a switch to another FLT3 inhibitor due to AEs. Disease relapse occurred in one patient during MT. At the time of the last follow-up, seven patients are alive and disease-free, while three have died due to infection or transplant complications.ConclusionIn relapsed/refractory FLT3 mutation-positive AML, the use of FLT3 inhibitors can lead to high response rates and provide a safe bridge from HCT to MT. If sufficient attention is paid to safety, this therapy is expected to prevent disease relapse even with reduced dosages.

Clinical characteristics and prognostic analysis of acute myeloid leukemia patients with PTPN11 mutations

ABSTRACT Objectives Little is known about the clinical impact of germline/somatic mutations of PTPN11 in acute leukemia. The aim of this study was to investigate the clinical characteristics and prognostic impact of PTPN11 mutations in patients with acute myeloid leukemia (AML). Methods: Seventy-four patients with PTPN11 mutation-positive AML treated at our institution were enrolled in this study. The prevalence of PTPN11 mutations was examined using targeted next-generation sequencing technology, and patients with AML and PTPN11 mutations were screened. Clinical characteristics, prognostic impact, and association between PTPN11 mutations and other mutations were analyzed retrospectively. Results: PTPN11 mutations co-occurred more commonly with DNMT3A, NPM1, and FLT3 internal tandem duplication mutations. Compared with PTPN11 wild-type (WT) patients, PTPN11 mutation-positive AML patients presented with higher white blood cell (WBC) and platelet (PLT) counts. In 74 PTPN11 positive AML patients, PTPN11 mutations had an adverse effect on overall survival (OS) (62.5%) and a negative prognostic effect on event-free survival (EFS) (50%). Allo-hematopoietic stem cell transplantation (HSCT) abrogated the negative effect of mutations in PTPN11; the OS and EFS of AML patients with PTPN11 mutations who received transplantation were longer than those of AML patients with PTPN11 mutations who did not undergo allo-HSCT (P = 0.001, EFS; P < 0.001, OS). Discussion: Newly diagnosed PTPN11 mutation-positive AML patients with high WBC and PLT counts or presenting no remission after first induction chemotherapy suffer from high mortality rates. Conclusion: Given the lack of targeted therapies for PTPN11 mutations, timely HSCT is necessary for patients.

Characteristics and Outcomes of Adult Patients in the PETHEMA Registry with Relapsed or Refractory FLT3-ITD Mutation-Positive Acute Myeloid Leukemia.

Simple SummaryMost adult patients with acute myeloid leukemia (AML) relapse after achieving complete remission with chemotherapy; however, there is no standard second-line (salvage) treatment. We retrospectively investigated 404 patients aged ≥18 years with relapsed/refractory (R/R) AML with an FMS-like tyrosine kinase 3 (FLT3) mutation, treated at a PETHEMA (NCT02607059) site between 1998 and 2018. Patients received salvage treatment with intensive therapy (n = 261), non-intensive therapy (n = 63) or supportive care (n = 80). Complete remission was achieved by 48% of patients who received intensive therapy vs. 19% with non-intensive therapy. Intensive/non-intensive therapy prolonged overall survival significantly compared with supportive therapy. Of evaluable patients, 22% received an allogeneic stem-cell transplant after complete remission. The majority of patients with FLT3-mutated R/R AML received intensive salvage therapy, with the best outcomes being obtained when intensive salvage treatment was combined with stem-cell transplant.This retrospective study investigated outcomes of 404 patients with relapsed/refractory (R/R) FMS-like tyrosine kinase 3 (FLT3)-internal tandem duplication (ITD) acute myeloid leukemia (AML) enrolled in the PETHEMA registry, pre-approval of tyrosine kinase inhibitors. Most patients (63%) had received first-line intensive therapy with 3 + 7. Subsequently, patients received salvage with intensive therapy (n = 261), non-intensive therapy (n = 63) or supportive care only (n = 80). Active salvage therapy (i.e., intensive or non-intensive therapy) resulted in a complete remission (CR) or CR without hematological recovery (CRi) rate of 42%. More patients achieved a CR/CRi with intensive (48%) compared with non-intensive (19%) salvage therapy (p < 0.001). In the overall population, median overall survival (OS) was 5.5 months; 1- and 5-year OS rates were 25% and 7%. OS was significantly (p < 0.001) prolonged with intensive or non-intensive salvage therapy compared with supportive therapy, and in those achieving CR/CRi versus no responders. Of 280 evaluable patients, 61 (22%) had an allogeneic stem-cell transplant after they had achieved CR/CRi. In conclusion, in this large cohort study, salvage treatment approaches for patients with FLT3-ITD mutated R/R AML were heterogeneous. Median OS was poor with both non-intensive and intensive salvage therapy, with best long-term outcomes obtained in patients who achieved CR/CRi and subsequently underwent allogeneic stem-cell transplant.

Real-World Use of FLT3 Tyrosine Kinase Inhibitors in Patients with Relapsed/Refractory FLT3 mutation-Positive Acute Myeloid Leukemia in the United States

Background: FLT3 tyrosine kinase inhibitors (TKIs) have improved outcomes in clinical trials for patients with FLT3 mutation-positive acute myeloid leukemia (FLT3mut+ AML). Gilteritinib is the first FDA-approved (11/28/2018) targeted therapy for relapsed/refractory (R/R) FLT3mut+ AML in adults, although two other multikinase inhibitors, midostaurin and sorafenib, are used off-label in this population. This analysis characterized treatment duration for these three drugs in R/R FLT3mut+ AML, as little is known about the treatment of patients receiving a FLT3 inhibitor in the real world.Aim/Objective: To describe real-world treatment patterns of patients newly initiating a FLT3 TKI for R/R AML following the launch of gilteritinib.Methods: This was a post hoc analysis of a US-based retrospective cohort study using IBM MarketScan claims data (1/1/2007-10/30/2020) to evaluate real-world treatment patterns. Adult patients (≥18 years) with R/R AML who newly initiated a FLT3 TKI (ie, ≥1 claim for gilteritinib, midostaurin, or sorafenib) on or after 12/1/2018 were eligible for inclusion. Included patients were required to have continuous enrollment starting 180 days prior to first AML diagnosis through first FLT3 TKI initiated for R/R AML on or after 12/1/2018 (index date). FLT3 TKI treatment duration was calculated as the difference between the first claim and the last day of supply or end of enrollment/study, whichever occurred first. Treatments that were not discontinued prior to the end of the study period (10/30/2020) were censored. Treatment duration was estimated using Kaplan-Meier analysis, and the hazard ratio for discontinuation was estimated with a Cox proportional hazards model. Additional subgroup analyses were conducted based on prior FLT3 TKI exposure for R/R AML and use of FLT3 TKI therapy alone or in combination with chemotherapy. Data from the ProMetrics specialty pharmacy database (12/6/2018-3/3/2021) were also analyzed to establish a benchmark for gilteritinib and validate the treatment duration in the MarketScan results.Results: A total of 65 patients newly initiating FLT3 TKIs for R/R AML were identified in the MarketScan database. Mean patient age was 53.4 years and mean Quan-Charlson Comorbidity index score at baseline was 5.1. Most patients initiating FLT3 TKI therapy received gilteritinib (n=44 [68%]). Patients initiating gilteritinib compared with other FLT3 TKIs had the highest prior history of high-intensity chemotherapy (n=24 [47%]) and hematopoietic stem cell transplantation (n=16 [31%]). Midostaurin was the most common prior TKI for patients who initiated sorafenib (n=6 [50%]) or gilteritinib (n=28 [55%]).The median (95% CI) treatment duration was 150 (73-260) days for gilteritinib (n=51), 60 (15-210) days for sorafenib (n=12), and 54 (28-268) days for midostaurin (n=12). Treatment duration was significantly longer for patients receiving gilteritinib compared with midostaurin (P=.0018) and sorafenib (P=.0016) in the Cox proportional hazards model (Table) and the Kaplan-Meier analysis (P=.0021) (Figure). Differences in gilteritinib duration in patients with prior TKI treatment versus no prior TKI treatment and patients who used a FLT3 TKI alone versus in combination with chemotherapy were not statistically significant (Table). The median gilteritinib treatment duration in the MarketScan data (150 days) was aligned with the median duration in the ProMetrics specialty pharmacy data (154 days), which validates the MarketScan results.Conclusions: This early look at treatment patterns suggests a median duration of therapy for gilteritinib of 150 days. Importantly, gilteritinib treatment duration does not appear to differ based on prior TKI treatment or overlapping use with chemotherapy. Small sample sizes precluded adjusted comparisons between the treatments. Gilteritinib was the most commonly used treatment. The availability of new targeted therapies such as gilteritinib is promising for patients with R/R FLT3mut+ AML and is changing the therapeutic landscape for this aggressive AML subtype. [Display omitted] DisclosuresGrinblatt: Astellas Pharma, Inc.: Consultancy; Bristol Myers Squibb: Consultancy; Astra Zeneca: Consultancy; AbbVie: Consultancy. Han: Astellas Pharma, Inc.: Current Employment. Nimke: Astellas Pharma, Inc.: Current Employment. Feng: Astellas Pharma, Inc.: Current Employment. Sullivan: Astellas Pharma, Inc.: Current Employment. Pandya: Astellas Pharma, Inc.: Current Employment.

Single-Strand Breaks at Genome Initiate FLT3-ITD Formation

Single-Strand Breaks at Genome Initiate FLT3-ITD Formation

FLT3-ITD Allele Frequency Is an Independent Prognostic Factor for Poor Outcome in FLT3-ITD–Positive AML Patients

FMS-like tyrosine kinase 3 internal tandem duplication (FLT3-ITD) is a molecular genetic alteration significantly affecting the clinical outcome in patients with acute myeloid leukemia (AML). FLT3-ITD mutations are characterized by variable mutant-to-wild allelic ratios (ARs) and sizes of the duplicated sequences. The size of the inserted sequence may vary from a few to hundreds of nucleotides. The aim of this work was to determine the impact of FLT3-ITD ARs, FLT3-ITD allelic frequency (AF), and allele size in de novo AML. We studied 117 patients with FLT3-ITD gene mutation-positive AML, dividing them into those with low ARs and those with high ARs (>0.64) and examined their prognostic impact. High FLT3-ITD AR ≥ 0.64 and AF ≥ 0.5 were significantly associated with a lower overall survival compared with lower AR (median 0.625 vs. 1.020 months, respectively; P=.041) and AF (median 0.493 vs. 0.954 months, respectively; P=.009). NPM1 mutation had no favorable impact on the low-level FLT3-ITD group. Initial high total leukocyte count, FLT3-ITD AF, and splenomegaly are independent prognostic factors for poor outcome in FLT3-ITD-positive AML.

Preclinical Evaluation of Gilteritinib on NPM1-ALK-Driven Anaplastic Large Cell Lymphoma Cells.

Anaplastic large cell lymphoma (ALCL) is an aggressive type of non-Hodgkin lymphoma. More than three-fourths of anaplastic lymphoma kinase (ALK)-positive ALCL cases express the nucleophosmin 1 (NPM1)-ALK fusion gene as a result of t(2;5) chromosomal translocation. The homodimerization of NPM1-ALK fusion protein mediates constitutive activation of the chimeric tyrosine kinase activity and downstream signaling pathways responsible for lymphoma cell proliferation and survival. Gilteritinib is a tyrosine kinase inhibitor recently approved by the FDA for the treatment of FMS-like tyrosine kinase mutation-positive acute myeloid leukemia. In this study, we demonstrate for the first time gilteritinib-mediated growth inhibitory effects on NPM1-ALK-driven ALCL cells. We utilized a total of five ALCL model cell lines, including both human and murine. Gilteritinib treatment inhibits NPM1-ALK fusion kinase phosphorylation and downstream signaling, resulting in induced apoptosis. Gilteritinib-mediated apoptosis was associated with caspase 3/9, PARP cleavage, the increased expression of proapoptotic protein BAD, and decreased expression of antiapoptotic proteins, survivin and MCL-1. We also found downregulation of fusion kinase activity resulted in decreased c-Myc protein levels. Furthermore, cell-cycle analysis indicated gilteritinib induced G0-G1-phase cell-cycle arrest and reduced CD30 expression. In summary, our preclinical studies explored the novel therapeutic potential of gilteritinib in the treatment of ALCL cells expressing NPM1-ALK and potentially in other ALK or ALK fusion-driven hematologic or solid malignancies. IMPLICATIONS: Our preclinical results explore the use of gilteritinib for the treatment of NPM1-ALK-driven ALCL cells and pave a path for developing future clinical trials. VISUAL OVERVIEW: http://mcr.aacrjournals.org/content/molcanres/19/5/913/F1.large.jpg.

Real-World Use of FLT3-TKIs in R/R FLT3-Mutated AML in the United States

Background: Targeted inhibition of the FLT3 tyrosine kinase is a treatment strategy for patients with relapsed or refractory, FLT3 mutation-positive acute myeloid leukemia (R/R FLT3mut+ AML). While the multikinase inhibitors, sorafenib and midostaurin, were not approved specifically for R/R AML, they are used off-label as treatment. Since FDA approval on 11/28/2018, gilteritinib has become the first globally approved targeted therapy for the treatment of R/R FLT3mut+ AML in adults. This study aims to understand the treatment landscape for R/R FLT3mut+ AML patients following the introduction of a new therapeutic agent. Aim/Objective: To describe the characteristics and treatment patterns of patients initiating FLT3 tyrosine kinase inhibitors (TKIs) for R/R FLT3mut+ AML in the real-world setting. Methods: This US-based retrospective cohort study was conducted using two separate closed-claims databases (MarketScan, 1/1/2007-2/29/2020; IQVIA, 1/1/2006-4/30/2020) and a specialty-pharmacy claims database (ProMetrics, 12/6/2018-3/12/2020). Patients ≥18 years of age, with an AML diagnosis and newly initiated FLT3-TKI (ie, gilteritinib, midostaurin, or sorafenib) therapy for R/R diagnosis or episode ("R/R AML") on or after gilteritinib market availability were eligible for inclusion. Patients were indexed on the first newly initiated FLT3-TKI for R/R AML observed on or after 12/1/2018. Patients' baseline clinical and demographic characteristics, AML-related treatments preceding FLT3-TKI initiation for R/R AML, and concomitant therapies (defined as any AML-related treatment overlapping with FLT3-TKI use after R/R AML) were identified. Because individual patients could have received more than one FLT3-TKI during the study period, treatment sequencing was analyzed by FLT3-TKI-containing regimens. Given the larger sample size available within the ProMetrics Specialty Pharmacy database, gilteritinib dose patterns and treatment duration were analyzed using de-identified dispensed prescription data from a separate gilteritinib-only cohort for greater precision. Descriptive statistics were used to evaluate all study outcomes, except for treatment duration, which was estimated using Kaplan-Meier life table analysis. Results: A total of 52 and 51 patients initiating FLT3-TKIs for R/R AML were identified in the MarketScan and IQVIA databases, respectively. The mean age of patients was 53.1 (MarketScan) and 52.3 years (IQVIA); patients had a mean ± SD Quan-Charlson Comorbidity Index of 3.6 ± 2.4 (MarketScan) and 3.7 ± 2.2 (IQVIA). Most patients treated with FLT3-TKIs for R/R AML during the study period were first initiated on gilteritinib (MarketScan: n=35 [67.3%], IQVIA: n=36 [70.6%]); sorafenib was the second most common FLT3-TKI (MarketScan: n=9 [17.3%], IQVIA: n=8 [15.7%]), followed by midostaurin (MarketScan: n=8 [15.4%], IQVIA: n=7 [13.7%]). During the study period, 61 and 55 FLT3-TKI-containing regimens among 52 and 51 R/R AML patients were identified across the MarketScan and IQVIA databases, respectively. Most FLT3-TKI-containing regimens for R/R AML included gilteritinib (MarketScan: n=43 [70.5%], IQVIA: n=38 [69.1%]). Prior exposure to other FLT3-TKIs for new onset and/or R/R AML indications was observed in up to 63% of gilteritinib-, 56% of sorafenib-, and 13% of midostaurin-containing regimens (Table). Following onset of R/R AML, gilteritinib was given without concomitant chemotherapy in 47% (Marketscan: 20/43) to 55% (IQVIA: 21/38) of gilteritinib regimens; in a smaller sample of sorafenib regimens, sorafenib was given without concomitant chemotherapy in up to 56% (IQVIA: 5/9) of regimens. Of 748 patients identified in the ProMetrics database with gilteritinib claims, 714 (95%) patients were initiated on a 120-mg daily dose, with less than 5% (n=34) incurring a downward dosage titration. The median treatment duration was 150 days (95% CI: 129-172 days). Conclusions: Among FLT3-TKI-containing regimens initiated for R/R AML after gilteritinib market approval, close to 70% included gilteritinib, an agent approved for R/R FLT3mut+ AML. Sample sizes for midostaurin- and sorafenib-containing regimens limited characterization of treatment patterns. Gilteritinib was given without concomitant chemotherapy in approximately 50% of regimens prescribed; the dose and treatment durations were similar to those previously reported by the ADMIRAL trial. Disclosures Grinblatt: Astellas: Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees; Alexion: Speakers Bureau. Pandya:Astellas Pharma, Inc.: Current Employment. Sullivan:Astellas Pharma: Current Employment. Feng:Astellas: Current Employment. Hedlund:Astellas: Current Employment.

Updated safety of midostaurin plus chemotherapy in newly diagnosed FLT3 mutation–positive acute myeloid leukemia: the RADIUS-X expanded access program

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.

Pharmacokinetic Profile of Gilteritinib: A Novel FLT-3 Tyrosine Kinase Inhibitor.

Background and ObjectiveGilteritinib 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.MethodsThe pharmacokinetic profile of gilteritinib was assessed from five clinical studies.ResultsDose-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.ConclusionsGilteritinib 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 RegistrationNCT02014558, NCT02456883, NCT02571816.Electronic supplementary materialThe online version of this article (10.1007/s40262-020-00888-w) contains supplementary material, which is available to authorized users.

A Study of CPX-351 (Vyxeos™) With Quizartinib for the Treatment of FLT3-ITD Mutation-Positive Acute Myeloid Leukemia

A Study of CPX-351 (Vyxeos™) With Quizartinib for the Treatment of FLT3-ITD Mutation-Positive Acute Myeloid Leukemia

Midostaurin: Nursing Perspectives on Managing Treatment and Adverse Events in Patients With FLT3 Mutation-Positive Acute Myeloid Leukemia and Advanced Systemic Mastocytosis.

Acute myeloid leukemia (AML) and advanced systemic mastocytosis (SM) are clonal diseases of the blood. Prognoses for patients with FMS-like tyrosine kinase 3 (FLT3) mutation-positive AML and those with advanced SM are poor. In the United States, midostaurin was approved in 2017 in combination with standard chemotherapy in patients with newly diagnosed FLT3 mutation-positive AML and as a single agent in patients with advanced SM. This article aims to improve oncology nurses' knowledge about the benefits and risks of midostaurin therapy and to provide guidance on the identification and management of eligible patients. The clinical data that supported the U.S. Food and Drug Administration's approval of midostaurin are reviewed, and supporting safety and management considerations are provided based on the authors' experiences as nurses and advanced practice providers caring for patients who received midostaurin during these key clinical trials. Nausea and vomiting are the most frequent nonhematologic adverse events reported with midostaurin; therefore, administer midostaurin with antiemetics, and recommend taking it with food. Care should be taken when midostaurin is coadministered with strong CYP3A4 inhibitors.

Preclinical Evaluation of Gilteritinib on NPM1-ALK Driven Anaplastic Large Cell Lymphoma Cells

Anaplastic large cell lymphoma (ALCL) is an aggressive type of non-Hodgkin's lymphoma (NHL) comprising 2-8% of adult and 10-20% of pediatric and adolescent NHL. More than three-fourths of anaplastic lymphoma kinase (ALK)-positive ALCL express (nucleophosmin1) NPM1-ALK fusion gene as a result of t(2;5) chromosomal translocation. The self-dimerization of fusion kinase NPM1-ALK mediates constitutive activation of the chimeric tyrosine kinase activity leading to downstream signaling pathways responsible for lymphoma cell proliferation and survival. The current standard treatment regimen for ALK+ ALCL is CHOP (cyclophosphamide, hydroxy doxorubicin, vincristine, prednisone) chemotherapy. Oftentimes, resistance and failure of remission occur with CHOP therapy, making it a suboptimal treatment regimen for many patients. Therefore, an alternative therapeutic approach is warranted to better address the needs of the ALK+ ALCL population. Gilteritinib is a recently FDA approved tyrosine kinase inhibitor for the treatment of FMS-like tyrosine kinase (FLT3) mutation-positive acute myeloid leukemia. Along with inhibition of FLT3, gilteritinib also inhibits other tyrosine kinases such as AXL and ALK. In this study, for the first time, we demonstrated gilteritinib mediated growth inhibitory effects on NPM1-ALK driven ALCL cells. We have used a total of five cell lines in our study: NPM1-ALK endogenously expressing human ALCL cell lines (SUDHL-1, SUP-M2, SR-786, and DEL), and our laboratory generated ectopically overexpressing Ba/F3-FG-NPM1-ALK, a murine cell line. Gilteritinib treatment (5-20 nM) inhibited NPM1-ALK fusion kinase phosphorylation, which resulted in downregulation of downstream survival signaling pathways including AKT, ERK1/2, and STAT3 leading to induced apoptosis and decreased clonogenic survival. Gilteritinib mediated apoptosis was associated with caspase 3/9 and poly (ADP-ribose) polymerase cleavage with increased pro-apoptotic protein BAD and decreased anti-apoptotic protein MCL-1. Increased expression of c-Myc is associated with ALK-positive ALCL and gilteritinib treatment decreased c-Myc levels in a dose dependent manner. Cell cycle analysis demonstrated gilteritinib treatment induced cell cycle arrest at the G0/G1 phase with a concomitant decrease in G2/M and S phases. In summary, our preclinical results suggest gilteritinib has therapeutic potential for the treatment of ALCL cells expressing NPM1-ALK and other ALK /ALK-fusion driven hematologic or solid malignancies. Disclosures Lin: Jazz Pharmaceuticals: Honoraria; Pfizer: Membership on an entity's Board of Directors or advisory committees. Ganguly:Daiichi Sankyo: Research Funding; Seattle Genetics: Speakers Bureau; Janssen: Honoraria, Other: Advisory Board; Kite Pharma: Honoraria, Other: Advisory Board. McGuirk:ArticulateScience LLC: Other: Assistance with manuscript preparation; Juno Therapeutics: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bellicum Pharmaceuticals: Research Funding; Astellas: Research Funding; Novartis: Research Funding; Fresenius Biotech: Research Funding; Pluristem Ltd: Research Funding; Gamida Cell: Research Funding; Kite Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau.

PDG8 COST-EFFECTIVENESS ANALYSIS OF MIDOSTAURIN (MIDO) + INTENSIVE CHEMOTHERAPY (SOC) FOR THE TREATMENT OF ACUTE MYELOID LEUKEMIA IN ADULTS WITH FLT3 MUTATION IN COLOMBIA

The objective of this study was to assess the cost-utility of using MIDOS + SoC for the treatment of newly-diagnosed FLT3 mutation-positive acute myeloid leukemia (AML) in adults in Colombia over a life time horizon. An adaptation of a partition survival model was used to estimate the effectiveness and costs associated with routine care of the disease, administration of AML treatment, adverse events of each treatment scheme included in the model, stem cell transplantation (SCT), and second-line treatments. The model has a Markov of discrete times and cycles of 28 days, which considers the progression to the main health states of a patient diagnosed with AML: induction, consolidation, relapse, complete remission, SCT, and death. From the phase III RATIFY study, we extracted data on overall survival (OS), complete remission and the frequency of adverse events. Health states utility data were obtained from international evidence. Health resource use was determined with the collaboration of a clinical expert. The costs were obtained from the SISMED 2017 report (Q1-Q4) and the ISS 2001 tariff manual (+ 30%). An incremental cost-effectiveness ratio of $ 164,359,267 COP was estimated, with a cost difference of $ 202,921,254 COP and 1.23 additional QALYs for midostaurin. The main variables that drive uncertainty in the results are the OS hazard ratio with MIDOS and the SCT rate. Taking the cost-effectiveness threshold recommended by WHO of 1 to 3 GDP per capita (COP $ 56,484,299.7), the combination of MIDOS + SoC in patients with FLT3+ AML is not cost-effective. However, a gain of 1.23 years of QALYs was observed for midostaurin, and lower costs for routine care and mortality were observed in the group of patients who started treatment with MIDOS.

Hybridization capture-based next generation sequencing reliably detects FLT3 mutations and classifies FLT3-internal tandem duplication allelic ratio in acute myeloid leukemia: a comparative study to standard fragment analysis

FLT3-internal tandem duplication occurs in 20–30% of acute myeloid leukemia and confers an adverse prognosis with its allelic ratio being a key risk stratifier. The US Food and Drug Administration recently approved FLT3 inhibitors midostaurin and gilteritinib in FLT3 mutation-positive acute myeloid leukemia. Historically, FLT3 was tested by fragment analysis, which has become the standard method endorsed by international guidelines. However, next generation sequencing is increasingly used at acute myeloid leukemia diagnosis given its ability to simultaneously evaluate multiple clinically informative markers. As FLT3-internal tandem duplication detection was known to be challenging by next generation sequencing and the results carry profound prognostic and therapeutic implications, it is important to thoroughly examine its performance in FLT3-internal tandem duplication detection and allelic ratio classification. In a comparative study with fragment analysis, we retrospectively reviewed our experience using a custom-designed, hybridization capture-based, targeted next generation sequencing panel. Among 7902 cases, FLT3-internal tandem duplication was detected in 335 with variable sizes (3–231 bp) and insertion sites. Fragment analysis was also performed in 402 cases, demonstrating 100% concordance in FLT3-internal tandem duplication detection. In 136 dual-tested, positive cases, 128/136 (94%) exhibited concordant high/low allelic ratio classifications. The remaining 6% showed borderline low allelic ratio by next generation sequencing. The two methods were concordant in FLT3-tyrosine kinase domain mutation detection at the hotspot D835/I836 targeted by fragment analysis. Furthermore, seven mutations which may benefit from FLT3 inhibitor therapy were detected by next generation sequencing, in regions not covered by fragment analysis. Our study demonstrates that using a hybridization capture-based chemistry and optimized bioinformatics pipeline, next generation sequencing can reliably detect FLT3-internal tandem duplication and classify its allelic ratio for acute myeloid leukemia risk stratification. Next generation sequencing also exhibits superior comprehensiveness in FLT3 mutation detection and may further improve personalized, targeted therapy in acute myeloid leukemia.

Sorafenib plus intensive chemotherapy improves survival in patients with newly diagnosed, FLT3-internal tandem duplication mutation-positive acute myeloid leukemia.

The addition of midostaurin to induction chemotherapy improves survival in younger patients with newly diagnosed, FLT3-mutated acute myeloid leukemia (AML). Sorafenib is a potent multikinase inhibitor with efficacy when given as monotherapy. The authors investigated whether the addition of sorafenib to intensive induction chemotherapy improves outcomes in patients with FLT3-internal tandem duplication (ITD)-mutated AML. In total, 183 patients who were newly diagnosed with FLT3-ITD-mutated AML between February 2001 and December 2017 were identified. Of these, 79 patients (43%) underwent intensive chemotherapy with the addition of sorafenib, and 104 (57%) received intensive chemotherapy alone. Propensity score matching identified 42 patients in each cohort. The overall response rate was 98% in the sorafenib cohort and 83% in the intensive chemotherapy cohort (P=.057). The median follow-up was 54months. The median event-free survival was 35months in the sorafenib cohort and 8months in the intensive chemotherapy cohort (P=.019), and the median overall survival was 42 and 13months, respectively (P=.026). With censoring at the time of allogeneic stem cell transplantation, the median event-free survival was 31 and 8months in the sorafenib and intensive therapy cohorts, respectively (P=.031), and the median overall survival was not reached and 10months, respectively (P=.001). Multivariate Cox proportional hazards models confirmed that treatment with sorafenib was a favorable prognostic factor (P=.009; hazard ratio, 0.558; 95% CI, 0.360-0.865). The addition of sorafenib improves survival in patients with FLT3-ITD-mutated AML regardless of whether they undergo allogeneic stem cell transplantation.

Effect of Mangiferin on Proliferation of FLT3-ITD Mutation Positive Acute Myeloid Leukemia Cell MV4-11 and Its Mechanism

To investigate the effects of mangiferin on proliferation, apoptosis and cycle of FLT3-ITD mutation-positive acute myeloid leukemia cells and its mechanism. The effects of different concentration of mangiferin on proliferation of MV4-11 cells were detected by CCK8 method. Apoptosis, cell cycle and FLT3 transmembrane protein expression were detected by flow cytometry. FLT3 mRNA expression was detected by real-time fluorescent quantitative polymerase chain reaction (PCR) . Mangiferin obviously inhibited MV4-11 proliferation in a concentration and time dependent manner (48 h，r=0.922；72 h，r=0.959；96 h，r=0.973). The ratio of G0/G1 phase in cell cycle increased with the enhancement of concentration of mangiferin in MV4-11 cells for 48 h, and the ratio of S phase decreased with enhasment of concentration. The increase of apoptosis was more obvious. The expression of FLT3 transmembrane protein significantly decreased after the actior of IC50 concentration of mangiferin in MV4-11 cells for 48 h. The results of qRT-PCR showed that the expression of FLT3 mRNA significantly decreased after treatment of MN4-11 cells with mangiferin (P＜0.05). Mangiferin inhibits MV4-11 cell proliferation, arrests cell cycle progression and promotes apoptosis, which may be related with the inhibition of FLT3 activity by mangiferin and the subsequent signaling pathways involved in apoptosis and proliferation of cells.