Optimizing maintenance therapy in acute myeloid leukemia: where do we stand in the year 2024?

INTRODUCTION: Despite the prognosis of patients affected by acute myeloid leukemia (AML) improved in the last decade, most patients relapse. Maintenance therapy after a chemotherapy approach with or without allogeneic stem cell transplantation could be a way to control the undetectable residual burden of leukemic cells. Several studies are being carried out as maintenance therapy in AML. Some critical points need to be defined, how the physician can choose among the various drugs available. AREAS COVERED: This review discusses the advances and controversies surrounding maintenance therapy for AML patients. EXPERT OPINION: Patients withFLT3-positive AML should receive midostaurin or quizartinib in the first-linesetting. For a patient initially receiving midostaurin, consider switching to sorafenib in the post-transplant setting. Because of the improved safety profile and potency, many experts will lean toward using a second-generation FLT3 inhibitor such as quizartinib or gilteritinib. Finally, no data indicate whether maintenance therapy should be prolonged until progression or for a defined period.

The impact of different FLT3-inhibitors on overall survival of de novo acute myeloid leukemia: A network meta-analysis.

FLT3 inhibitors combined with chemotherapy are the standard of care for newly diagnosed FLT3-mutated acute myeloid leukemia (AML). However, no head-to-head studies have established the superiority of one FLT3 inhibitor over another. We conducted a network meta-analysis (NMA) to evaluate overall survival (OS) among different FLT3 inhibitors. Three relevant randomized controlled trials (RCTs), involving 1.358 patients treated with midostaurin, quizartinib, and sorafenib, were included in our analysis. The hazard ratios (HRs) revealed no significant differences in OS between midostaurin and quizartinib (HR, 1.00; 95 % CI, 0.73-1.36), midostaurin and sorafenib (HR, 0.97; 95 % CI, 0.52-1.84), or quizartinib and sorafenib (HR, 0.97; 95 % CI, 0.51-1.85). This NMA, the first to explore this issue, found no OS differences among the different FLT3 inhibitors. In the absence of direct comparison trials, our findings provide practical insights for clinical decision-making.

The potential of triplet combination therapies for patients with FLT3-ITD -mutated acute myeloid leukemia.

INTRODUCTION: Acute myeloid leukemia (AML) encompasses a heterogeneous group of aggressive myeloid malignancies, where FMS-like tyrosine kinase 3 (FLT3) mutations are prevalent, accounting for approximately 25-30% of adult patients. The presence of this mutation is related to a dismal prognosis and high relapse rates. In the lasts years many FLT3 inhibitors have been developed. AREAS COVERED: This review provides a comprehensive overview of FLT3mut AML, summarizing the state of art of current treatment and available data about combination strategies including an FLT3 inhibitor. EXPERT OPINION: In addition, the review discusses the emergence of drug resistance and the need for a nuanced approaches in treating patients who are ineligible for or resistant to intensive chemotherapy. Specifically, it explores the historical context of FLT3 inhibitors (FLT3Is) and their impact on treatment outcomes, emphasizing the pivotal role of midostaurin, as well as gilteritinib and quizartinib, and providing detailed insights into ongoing trials exploring the safety and efficacy of novel triplet combinations involving FLT3Is in different AML settings.

Day-21 bone marrow findings incorrectly designate residual leukaemia in FLT3-mutated acute myeloid leukaemia treated with intensive induction plus midostaurin: a morphology-focused study.

Early induction response assessment with day-21 bone marrow (D21-BM) is commonly performed in patients with FLT3-mutated acute myeloid leukaemia (AML), where detection of residual leukaemia (RL; blasts ≥5%) typically results in the administration of a second induction course. However, whether D21-BM results predict for RL at the end of first induction has not been systematically assessed. This study evaluates the predictive role of D21-BM morphology in detecting RL following first induction. Between August 2018 and March 2022, all patients with FLT3-AML receiving 7+3 plus midostaurin, with D21-BM performed, were identified. Correlation between D21-BM morphology vs D21-BM ancillary flow/molecular results, as well as vs D28-BM end of first induction response, were retrospectively reviewed. Subsequently, D21-BMs were subjected to anonymised morphological re-assessments by independent haematopathologists (total in triplicate per patient). Of nine patients included in this study, three (33%) were designated to have RL at D21-BM, all of whom entered complete remission at D28-BM. Furthermore, only low-level measurable residual disease was detected in all three cases by flow or molecular methods at D21-BM, hence none proceeded to a second induction. Independent re-evaluations of these cases failed to correctly reassign D21-BM responses, yielding a final false positive rate of 33%. In summary, based on morphology alone, D21-BM assessment following 7+3 intensive induction plus midostaurin for FLT3-AML incorrectly designates RL in some patients; thus correlating with associated flow and molecular results is essential before concluding RL following first induction. Where remission status is unclear, repeat D28-BMs should be performed.

Gemtuzumab ozogamicin plus midostaurin in combination with standard '7 + 3' induction therapy in newly diagnosed AML: Results from the SAL-MODULE phase I study.

We conducted a phase I trial in newly diagnosed acute myeloid leukaemia (AML) to investigate the combination of two novel targeted agents, gemtuzumab ozogamicin (GO) and midostaurin, with intensive chemotherapy in FLT3-mutated AML and CBF leukaemia. Three dose levels of midostaurin and one to three sequential doses of 3 mg/m2 GO in combination with '7 + 3' induction were evaluated. Based on safety findings in 12 patients, our results show that 3 mg/m2 GO on Days 1 + 4 and 100 mg midostaurin on Days 8-21 can be safely combined with IC in newly diagnosed AML.

Quantification of midostaurin in plasma and serum by stable isotope dilution liquid chromatography-tandem mass spectrometry: Application to a cohort of patients with acute myeloid leukemia.

OBJECTIVES: Midostaurin is an oral multitargeted tyrosine kinase inhibitor for the treatment of acute myeloid leukemia (AML). Therapeutic drug monitoring of midostaurin may support its safe use when suspecting toxicity or combined with strong CYP3A4 inhibitors. METHODS: A stable isotope dilution liquid chromatography-tandem mass spectrometry method was developed and validated for the determination and quantification of midostaurin in human plasma and serum. Midostaurin serum concentrations were analyzed in 12 patients with FMS-like tyrosine kinase 3 (FLT3)-mutated AML during induction chemotherapy with cytarabine, daunorubicin, and midostaurin. Posaconazole was used as prophylaxis of invasive fungal infections. RESULTS: Linear quantification of midostaurin was demonstrated across a concentration range of 0.01-8.00 mg/L. Inter- and intraday imprecisions of the proposed method were well within ±10%. Venous blood samples were taken in nine and three patients in the first and second cycle of induction chemotherapy. Median (range) midostaurin serum concentration was 7.9 mg/L (1.5-26.1 mg/L) as determined in 37 independent serum specimens. CONCLUSION: In a real-life cohort of AML patients, interindividual variability in midostaurin serum concentrations was high, highlighting issues concerning optimal drug dosing in AML patients. A personalized dosage approach may maximize the safety of midostaurin. Prospective studies and standardization of analytical methods to support such an approach are needed.

Case Report: Molecular and microenvironment change upon midostaurin treatment in mast cell leukemia at single-cell level.

Mast cell leukemia is a rare and aggressive disease, predominantly with KIT D816V mutation. With poor response to conventional poly-chemotherapy, mast cell leukemia responded to the midostaurin treatment with a 50% overall response rate (ORR), but complete remission rate is approximately 0%. Therefore, the potential mechanisms of midostaurin resistance and the exact impacts of midostaurin on both gene expression profile and mast cell leukemia microenvironment in vivo are essential for design tailored combination therapy targeting both the tumor cells and the tumor microenvironment. Here we report a 59-year-old male mast cell leukemia patient with KIT F522C mutation treated with midostaurin. Single-cell sequencing of peripheral blood and whole exome sequencing (WES) of bone marrow were performed before and 10 months after midostaurin treatment. In accordance with the clinical response, compared to the pretreatment aberration, the decline of mast cells and increase of T-, NK, B-cells in peripheral blood, and the decrease of the KIT F522C mutation burden in bone marrow were observed. Meanwhile, the emergence of RUNX1 mutation, upregulations of genes expression (RPS27A, RPS6, UBA52, RACK1) on tumor cells, and increased frequencies of T and NK cells with TIGIT, CTLA4, and LAG3 expression were observed after midostaurin treatment, predicting the disease progression of this patient. As far as we know, this is the first case reporting the clinical, immunological, and molecular changes in mast cell leukemia patients before and after midostaurin treatment, illustrating the in vivo mechanisms of midostaurin resistance in mast cell leukemia, providing important clues to develop a sequential option to circumvent tumor progression after targeting oncogene addiction and prolong patients' survival.

A Functional Pipeline of Genome-Wide Association Data Leads to Midostaurin as a Repurposed Drug for Alzheimer's Disease.

Genome-wide association studies (GWAS) constitute a powerful tool to identify the different biochemical pathways associated with disease. This knowledge can be used to prioritize drugs targeting these routes, paving the road to clinical application. Here, we describe DAGGER (Drug Repositioning by Analysis of GWAS and Gene Expression in R), a straightforward pipeline to find currently approved drugs with repurposing potential. As a proof of concept, we analyzed a meta-GWAS of 1.6 × 107 single-nucleotide polymorphisms performed on Alzheimer's disease (AD). Our pipeline uses the Genotype-Tissue Expression (GTEx) and Drug Gene Interaction (DGI) databases for a rational prioritization of 22 druggable targets. Next, we performed a two-stage in vivo functional assay. We used a C. elegans humanized model over-expressing the Aß1-42 peptide. We assayed the five top-scoring candidate drugs, finding midostaurin, a multitarget protein kinase inhibitor, to be a protective drug. Next, 3xTg AD transgenic mice were used for a final evaluation of midostaurin's effect. Behavioral testing after three weeks of 20 mg/kg intraperitoneal treatment revealed a significant improvement in behavior, including locomotion, anxiety-like behavior, and new-place recognition. Altogether, we consider that our pipeline might be a useful tool for drug repurposing in complex diseases.

Gilteritinib activity in refractory or relapsed FLT3-mutated acute myeloid leukemia patients previously treated by intensive chemotherapy and midostaurin: a study from the French AML Intergroup ALFA/FILO.

The real-world efficacy and safety of gilteritinib was assessed in an ambispective study that included 167 R/R FLT3-mutated AML patients. Among them, 140 received gilteritinib as single agent (cohort B), including 67 previously treated by intensive chemotherapy and midostaurin (cohort C). The main differences in patient characteristics in this study compared to the ADMIRAL trial were ECOG ≥ 2 (83.6% vs. 16.6%), FLT3-TKD mutation (21.0% vs. 8.5%), primary induction failure (15.0% vs. 40.0%) and line of treatment (beyond 2nd in 37.1% vs. 0.0%). The rates of composite complete remission, excluding those that occurred after hematopoietic stem cell transplantation (HSCT), were similar at respectively 25.4% and 27.5% in cohorts B and C. Median overall survival (OS) for these two groups was also similar at respectively 6.4 and 7.8 months. Multivariate analyses for prognostic factors associated with OS identified female gender (HR 1.61), adverse cytogenetic risk (HR 2.52), and allogenic HSCT after gilteritinib (HR 0.13). Although these patients were more heavily pretreated, these real-world data reproduce the results of ADMIRAL and provide new insights into the course of patients previously treated by intensive chemotherapy and midostaurin and beyond the 2nd line of treatment who can benefit from treatment in an outpatient setting.

Evaluation of antitrypanosomal properties and apoptotic effects of ochrolifuanine from Dyera costulata (Miq.) Hook.f against Trypanosoma brucei brucei.

Trypanosoma brucei parasites are flagellated kinetoplastid protozoan which is responsible for Human African Trypanosomiasis (HAT). Current chemotherapy drugs have a number of side effects and drug resistance has emerged as a major issue in current treatment. Active bisindole alkaloid compound ochrolifuanine was previously isolated from the leaves of Dyera costulata. In vitro antitrypanosomal activity of ochrolifuanine against Trypanosoma brucei brucei strain BS221 showed strong activity with an IC50 value of 0.05 ± 0.01 µg/ml. We compared the effect of ochrolifuanine and reference compound staurosporine in T. b. brucei apoptosis. The apoptosis-inducing activity of ochrolifuanine was evaluated using TUNEL assay and cell cycle analysis. Trypanosoma brucei brucei was shown to undergo apoptotic cells death as demonstrated by the appearance of several conical hallmarks of apoptosis. Ochrolifuanine was found to induce apoptosis in parasites in a dose- and time-dependent manner. The cell cycle study revealed 0.025 and 0.05 µg/ml of ochrolifuanine arrested the growth of T. b. brucei at two different growth phases (G0/G1 and in S phases). While at concentration 0.10 µg/ml arrested at the G2/M phase. In conclusion, the results indicate that ochrolifuanine displayed an antitrypanosomal effect on T. b. brucei by inducing apoptosis cell death and causing the arrest of parasite cells at different growth phases. The results suggested that ochrolifuanine may be a promising lead compound for the development of new chemotherapies for African trypanosomiasis.

Drug-induced mast cell eradication: A novel approach to treat mast cell activation disorders?

Mast cell (MC) activation is a key event in allergic reactions, other inflammatory states, and MC activation syndromes. MC-stabilizing agents, mediator-targeting drugs, and drugs interfering with mediator effects are often prescribed for these patients. However, the clinical efficacy of these drugs varies depending on the numbers of involved MCs and the underlying pathology. One straightforward approach would be to eradicate the primary target cell. To date however, no MC-eradicating treatment approach has been developed for patients with MC activation disorders. Nevertheless, recent data suggest that long-term treatment with agents effectively inhibiting KIT function results in the virtual eradication of tissue MCs and a sustained decrease in serum tryptase levels. In many of these patients, MC depletion is associated with a substantial improvement in mediator-induced symptoms. In patients with an underlying KIT D816V-positive mastocytosis, such MC eradication requires an effective inhibitor of KIT D816V, such as avapritinib. However, the use of KIT inhibitors must be balanced against their potential side effects. Here we discuss MC-eradicating strategies in various disease models, the feasibility of this approach, available clinical data, and future prospects for the use of KIT-targeting drugs in MC activation disorders.

Practical tips for managing FLT3 mutated acute myeloid leukemia with midostaurin.

INTRODUCTION: FLT3 inhibitors have been recently introduced as novel treatment targets in patients with FLT3-mutated acute myeloid leukemia (AML). Midostaurin is an oral multikinase inhibitor that targets multiple receptor tyrosine kinases including FLT3 and has been approved for the treatment of AML with FLT3 mutations in patients candidates for intensive chemotherapy. This article presents an updated overall overview of the use of midostaurin in clinical practice. AREAS COVERED: Tests and examinations to be performed before the use of midostaurin, antifungal and antimicrobial treatment, as well as antifungal and antimicrobial prophylaxis are discussed. Practical tips for the treatment of QTc interval prolongation and heart failure are also presented. EXPERT OPINION: Midostaurin is the first agent showing significant survival benefit when combined with chemotherapy in FLT3-mutated AML patients. Optimal use of midostaurin should be a priority, being essential to know the interactions with other drugs like strong CYP3A4 inhibitors or inducers, which are particularly used in the concomitant treatment of AML patients and may increase toxicity or decrease therapeutic benefit. The active role of hematologists and nursing teams is crucial to ensure patient adherence to midostaurin treatment and to minimize adverse effects by administrating the optimal dose for each situation.