Gilteritinib with or without venetoclax for relapsed/refractory FLT3-mutated acute myeloid leukaemia.

Patients with FLT3-mutated acute myeloid leukaemia (AML) that relapse or are refractory (R/R) to intensive induction have poor outcomes. Gilteritinib has recently become standard-of-care for patients with R/R FLT3-mutated AML. We investigated whether adding venetoclax to gilteritinib (gilt-ven) improves outcomes as compared with gilteritinib monotherapy. We included patients treated with gilteritinib (n = 19) and gilt-ven (n = 17) for R/R AML after intensive chemotherapy. Gilteritinib and gilt-ven groups did not differ in terms of mCRc rates (53% and 65%, p = 0.51) and realization of allogeneic haematopoietic stem-cell transplantation (HSCT, 47% and 35%, p = 0.5). Overall survival (OS) was comparable between groups, although a trend towards better OS was seen with gilt-ven (12-month OS 58.8% [95% CI 39.5%-87.6%]) versus gilteritinib (42.1% [95% CI 24.9%-71.3%] for gilteritinib). Early salvage with gilt-ven versus any other gilteritinib-based approach was associated with the best outcome (p = 0.031). Combination therapy was associated with increased haematological toxicity. In summary, gilt-ven did not improve remissions or HSCT-realization rates in patients with R/R FLT3-mutated AML as compared with gilteritinib and was associated with increased haematological toxicity. Although OS did not differ, a trend towards better survival was suggested with gilt-ven and a survival benefit was shown for gilt-ven approach when sequenced early for salvage.

Venetoclax resistance in acute myeloid leukaemia-Clinical and biological insights.

Venetoclax, an oral BCL-2 inhibitor, has been widely incorporated in the treatment of acute myeloid leukaemia. The combination of hypomethylating agents and venetoclax is the current standard of care for elderly and patient's ineligible for aggressive therapies. However, venetoclax is being increasingly used with aggressive chemotherapy regimens both in the front line and in the relapse setting. Our growing experience and intensive research demonstrate that certain genetic abnormalities are associated with venetoclax sensitivity, while others with resistance, and that resistance can emerge during treatment leading to disease relapse. In the current review, we provide a summary of the known mechanisms of venetoclax cytotoxicity, both regarding the inhibition of BCL-2-mediated apoptosis and its effect on cell metabolism. We describe how these pathways are linked to venetoclax resistance and are associated with specific mutations. Finally, we provide the rationale for novel drug combinations in current and future clinical trials.

Impact of Folinic Acid Dosing on Efficacy and Toxicity of High-Dose Methotrexate in Central Nervous System Lymphoma.

INTRODUCTION: High-dose methotrexate (HDMTX)-based regimens are the treatment of choice in primary central nervous system lymphoma (PCNSL). Folinic acid (FA) rescue is used to mitigate the toxic effects of MTX on normal cells. However, the optimal dosing of FA in PCNSL remains uncertain. METHODS: We analyzed the relationship between FA dosing and treatment efficacy and toxicity in a cohort of 36 PCNSL patients treated at our institute between the years 2014 and 2022. A combination of univariate and multivariate analyses using known prognostic factors were used to determine the association between FA dosing and treatment outcomes. RESULTS: We found that higher per-treatment cumulative FA doses were associated with inferior progression-free survival (PFS), with a hazard ratio (HR) of 2.2 for each 100 mg/m2 increase in FA dose. We identified a threshold of 350 mg/m2/treatment, above which there was a significant reduction in PFS. Notably, lower FA doses did not result in increased toxicity. CONCLUSION: Our findings suggest that optimizing FA dosing to avoid very high rescue doses may improve treatment outcomes in PCNSL patients receiving HDMTX. Further prospective studies are warranted to validate these findings.

Standardization of Molecular MRD Levels in AML Using an Integral Vector Bearing ABL and the Mutation of Interest.

Quantitative PCR for specific mutation is being increasingly used in Acute Myeloid Leukemia (AML) to assess Measurable Residual Disease (MRD), allowing for more tailored clinical decisions. To date, standardized molecular MRD is limited to typical NPM1 mutations and core binding factor translocations, with clear prognostic and clinical implications. The monitoring of other identified mutations lacks standardization, limiting its use and incorporation in clinical trials. To overcome this problem, we designed a plasmid bearing both the sequence of the mutation of interest and the ABL reference gene. This allows the use of commercial standards for ABL to determine the MRD response in copy number. We provide technical aspects of this approach as well as our experience with 19 patients with atypical NPM1, RUNX1 and IDH1/2 mutations. In all cases, we demonstrate a correlation between response and copy number. We further demonstrate how copy number monitoring can modulate the clinical management. Taken together, we provide proof of concept of a novel yet simple tool, which allows in-house MRD monitoring for identified mutations, with ABL-based commercial standards. This approach would facilitate large multi-center studies assessing the clinical relevance of selected MRD monitoring.

Mesenchymal Stromal Cell-Derived Small Extracellular Vesicles Modulate Apoptosis, TNF Alpha and Interferon Gamma Response Gene mRNA Expression in T Lymphocytes.

Recent studies have highlighted the therapeutic potential of small extracellular bodies derived from mesenchymal stem cells (MSC-sEVs) for various diseases, notably through their ability to alter T-cell differentiation and function. The current study aimed to explore immunomodulatory pathway alterations within T cells through mRNA sequencing of activated T cells cocultured with bone marrow-derived MSC-sEVs. mRNA profiling of activated human T cells cocultured with MSC-sEVs or vehicle control was performed using the QIAGEN Illumina sequencing platform. Pathway networks and biological functions of the differentially expressed genes were analyzed using Ingenuity pathway analysis (IPA)® software, KEGG pathway, GSEA and STRING database. A total of 364 differentially expressed genes were identified in sEV-treated T cells. Canonical pathway analysis highlighted the RhoA signaling pathway. Cellular development, movement, growth and proliferation, cell-to-cell interaction and inflammatory response-related gene expression were altered. KEGG enrichment pathway analysis underscored the apoptosis pathway. GSEA identified enrichment in downregulated genes associated with TNF alpha and interferon gamma response, and upregulated genes related to apoptosis and migration of lymphocytes and T-cell differentiation gene sets. Our findings provide valuable insights into the mechanisms by which MSC-sEVs implement immunomodulatory effects on activated T cells. These findings may contribute to the development of MSC-sEV-based therapies.

Clonal Myeloid Dysplasia Following CAR T-Cell Therapy: Chicken or the Egg?

Multiple myeloma (MM) is characterized by recurrent relapses. Consequently, patients receive multiple therapy lines, including alkylating agents and immune modulators, which have been associated with secondary malignancies such as myelodysplastic syndrome (MDS). Anti-B-cell maturation antigen (BCMA) chimeric antigen receptor T cell (CART) therapy is efficacious in patients with relapsed/refractory (R/R) MM. However, the long-term complications, particularly MDS, are not well understood. Whether CART therapy causes or promotes MDS has not been thoroughly investigated. In this study, we explored the causal relationship between MDS and CART therapy. We retrospectively examined the prevalence of MDS-related morphological and mutational changes before and after administration of CART therapy in five patients. Among them, four developed MDS after CART therapy, while one had pre-existing MDS prior to CART. None of the four patients who developed post-CART MDS showed morphological MDS changes prior to CART therapy. However, all four patients exhibited molecular alterations associated with MDS in their pre-CART as well as post-CART therapy bone marrow. No new mutations were observed. Our findings provide initial evidence suggesting that anti-BCMA CART therapy in MM may promote expansion of pre-existing MDS clones rather than causing development of new clones.

Comparing end-of-life care of hematologic malignancy versus solid tumor patients in a tertiary care center.

OBJECTIVES: To compare end-of-life (EOL) care for solid tumor and hematologic malignancy (HM) patients. METHODS: We collected data on the last 100 consecutive deceased HM and 100 consecutive deceased solid tumor patients who died prior to June 1st 2020, treated at a single center. We compared demographic parameters, cause of death as ascertained by review of medical records by two independent investigators, and EOL quality indicators including: place of death, use of chemotherapy or targeted/biologic treatment, emergency department visits as well as hospital, inpatient hospice and Intensive Care Unit admissions and the time spent as inpatient over the last 30 days of life; mechanical ventilation and use of blood products during the last 14 days of life. RESULTS: In comparison with solid tumor patients, HM patients more commonly died from treatment complications (13% vs. 1%) and unrelated causes (16% vs. 2%, p < .001 for all comparisons). HM patients died more frequently than solid tumor patients in the intensive care unit (14% vs. 7%) and the emergency department (9% vs. 0%) and less frequently in hospice (9% vs. 15%, p = .005 for all comparisons). In the 2 weeks prior to death HM patients were more likely than solid tumor patients to undergo mechanical ventilation (14% vs. 4%, p = .013), receive blood (47% vs. 27%, p = .003) and platelet transfusions (32% vs. 7%, p < .001); however, no statistical difference was found in use of either of chemotherapy (18% vs. 13%, p = .28) or targeted treatment (10% vs. 5%, p = .16). CONCLUSIONS: HM patients were more likely than solid tumor patients to undergo aggressive measures at EOL. Rarity of HM deaths, frequently caused by complications of treatment and unrelated causes, may affect treatment choices at EOL.

Rituximab versus obinutuzumab-based first-line chemoimmunotherapy for follicular lymphoma-a real-world multicenter retrospective cohort study.

The GALLIUM study showed a progression-free survival advantage of 7% in favor of obinutuzumab vs. rituximab-based immunochemotherapies as first-line therapy in follicular lymphoma (FL) patients. Yet, the toxicity appears to be increased with obinutuzumab-based therapy. This is a multicenter retrospective-cohort study including adult FL patients comparing the toxicity of first-line rituximab vs. obinutuzumab-based chemo-immunotherapies (R and O groups, respectively). We compared the best standard-of-care therapy used per time period, before and after obinutuzumab approval. The primary outcome was any infection during induction and 6 months post-induction. Secondary outcomes included rates of febrile neutropenia, severe and fatal infections, other adverse events, and all-cause mortality. Outcomes were compared between groups. A total of 156 patients were included in the analysis, 78 patients per group. Most patients received bendamustine (59%) or CHOP (31.4%) as adjacent chemotherapy. Half of the patients received growth-factor prophylaxis. Overall, 69 patients (44.2%) experienced infections, and a total of 106 infectious episodes were recorded. Patients in the R and O groups had similar rates of any infection (44.8% and 43.5%, p = 1), severe infections (43.3% vs. 47.8%, p = 0.844), febrile neutropenia (15% vs. 19.6%, p = 0.606), and treatment discontinuation, as well as similar types of infections. No covariate was associated with infection in multivariable analysis. No statistically significant difference was evident in adverse events of grades 3-5 (76.9% vs. 82%, p = 0.427). To conclude, in this largest real-life study of first-line treated FL patients comparing R- to O-based therapy, we did not observe any difference in toxicity during the induction and 6 months post-induction period.

Utility of Galactomannan Screening for Early Detection of Invasive Aspergillosis in High-Risk Hemato-Oncology Patients.

INTRODUCTION: Invasive aspergillosis (IA) affects mainly patients with hematological malignancies, and early diagnosis is crucial for timely treatment. Most diagnoses are based on clinical and mycological criteria, mostly galactomannan (GM) test in serum or bronchoalveolar fluid, which is performed in case of clinical suspicion or as routine screening in patients at high risk who are not receiving anti-mold prophylaxis, for early detection of IA. The aim of this study was to assess in a real-world setting the efficacy of biweekly serum GM screening for the early detection of IA. METHODS: A retrospective cohort that included 80 adult patients treated at the Hematology Department, Hadassah Medical Center, 2016-2020, with a diagnosis of IA. Clinical and laboratory data were collected from patients' medical files and the rate of GM-driven, GM-associated, and non-GM-associated IA was calculated. RESULTS: There were 58 patients with IA. The rate of GM-driven diagnosis was 6.9%, GM-associated diagnosis was 43.1%, and non-GM-associated diagnosis was 56.9%. The GM test as a screening tool had led to IA diagnosis in only 0.2% of screened serums with a number needed to screen in order to find 1 patient with IA of 490. CONCLUSION: Clinical suspicion outweighs GM screening as a tool for early diagnosis of IA. Nevertheless, GM has an important role as a diagnostic tool for IA.

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

OBJECTIVES: Dysregulation of BCL-2 family members has been reported in acute lymphocytic leukemia (ALL), with various BH3-dependencies of the leukemic clone. We conducted a multicenter retrospective cohort of patients with relapsed/refractory B or T ALL, with ven-chemotherapy or ven-navitoclax combinations, to assess efficacy and safety. METHODS: Seventeen patients were included in the analysis, median age was 32 years, with 6 B-ALL and 11 T-ALL patients. Nine patients received venetoclax combined with chemotherapy, and 13 patients received venetoclax in combination with navitoclax, vincristine and asparaginase, of which 5 were already exposed to venetoclax in previous lines. RESULTS: ORR was 55% and 46% among the ven-chemotherapy and the ven-navitoclax-chemotherapy, respectively. Most of the responders proceeded to an allogenic bone marrow transplant in both cohorts. The most common adverse effects of the ven-navitoclax combination were infectious complications and hepatotoxicity. CONCLUSIONS: Our data demonstrated the possible efficacy of ven-chemotherapy and ven-navitoclax in r/r ALL with moderate toxicity.

Risk factors and outcomes of COVID-19 in adult patients with hematological malignancies: A single-center study showing lower than expected rates of hospitalization and mortality.

BACKGROUND: Studies addressing coronavirus disease 2019 (COVID-19) in patients with hematological malignancies have reported mortality rates of up to 40%; however, included predominantly hospitalized patients. METHODS: During the first year of the pandemic, we followed adult patients with hematological malignancies treated at a tertiary center in Jerusalem, Israel, who contracted COVID-19, with the aim of studying risk factors for adverse COVID-19-related outcomes. We used remote communication to track patients managed at home-isolation, and patient questioning to assess the source of COVID-19 infection, community versus nosocomial. RESULTS: Our series included 183 patients, median age was 62.5 years, 72% had at least one comorbidity and 39% were receiving active antineoplastic treatment. Hospitalization, critical COVID-19, and mortality rates were 32%, 12.6%, and 9.8%, respectively, remarkably lower than previously reported. Age, multiple comorbidities, and active antineoplastic treatment were significantly associated with hospitalization due to COVID-19. Treatment with monoclonal antibodies was strongly associated with both hospitalization and critical COVID-19. In older (≥60) patients not receiving active antineoplastic treatment, mortality, and severe COVID-19 rates were comparable to those of the general Israeli population. We did not detect patients that contracted COVID-19 within the Hematology Division. CONCLUSION: These findings are relevant for the future management of patients with hematological malignancies in COVID-19-affected regions.

Successful treatment with plasma exchange in life-threatening hyperhemolytic syndrome unrelated to sickle cell disease.

INTRODUCTION: Hyperhemolytic syndrome (HHS) is a severe form of delayed transfusion reaction primarily described in sickle cell anemia patients which is characterized by a hemoglobin decrease to pre-transfusion levels or lower, often with reticulocytopenia and no evidence of auto- or allo-antibodies. CASE PRESENTATION: We present two cases of severe HHS in patients without sickle cell anemia refractory to treatment with steroids, immunoglobulins, and rituximab. In one case, temporary relief was achieved with eculizumab. In both cases, plasma exchange resulted in a profound and immediate response allowing for splenectomy and resolution of hemolysis. DISCUSSION/CONCLUSION: We discuss the pathophysiology of HHS, its presentation and treatment and expand on the possible role of plasma exchange in this setting.

The Emerging Role of Venetoclax-Based Treatments in Acute Lymphoblastic Leukemia.

Venetoclax, a B-cell lymphoma (BCL-2) inhibitor, in combination with hypomethylating agents has become the new standard of care in elderly and unfit patients with acute myeloid leukemia, with significantly improved overall survival and quality of life. Studies of venetoclax combined with high-dose chemotherapy are emerging with evidence of higher rates of molecular remission. Recently, a growing number of publications bring forth the use of venetoclax in patients with acute lymphoblastic leukemia (ALL). In the current review, we present the biological rationale of BCL-2 inhibition in ALL, how the interplay of BH3 proteins modulate the response and the current clinical experience with various combinations.

Monitoring Minimal Residual Disease in RUNX1-Mutated Acute Myeloid Leukemia.

INTRODUCTION: Mutated RUNX1 is considered a poor prognostic factor and usually is mutually exclusive with NPM1 mutations. Monitoring of molecular markers for minimal residual disease provides a powerful tool to assess remission and guide clinical decisions. METHODS: Newly diagnosed RUNX1-mutated AML patients, designated to intensive chemotherapy-based treatment or nonintensive regimens, were monitored for mutated RUNX1 transcript levels by qPCR with patient-specific primers. Samples were obtained along the treatment course and follow-up. RESULTS: A clear correlation was observed between mutated RUNX1 levels and response to treatment as observed by flow cytometry and STR-based assessment. CONCLUSION: We demonstrate the feasibility of RUNX1-based MRD to correlate with the clinicopathological status of leukemia. We further suggest how RUNX1 qPCR monitoring can influence clinical decision-making and contribute to improved personalized patient care.

Re-induction versus salvage for D14-resiudal acute myeloid leukemia: A retrospective multi-center study.

Remission assessment in acute myeloid leukemia has evolved over the recent years with the advent of molecular and flow-based minimal residual disease determination. Nonetheless, early time point such as day 5 and day 14 (D14), still have prognostic and therapeutic implications. D14 refractory disease is regarded as a poor prognostic factor, however the therapeutic intervention is still under debate, with evidence suggesting a successful re-induction might offer similar long-term outcome as D14 aplasia. Others advocate the use of more intensive salvage protocols as a mean to overcome the negative prognostic effect. In the current study, we compare outcome of D14 refractory AML patients treated with either re-induction or salvage protocol. More importantly, we identify response characteristics that might suggest which patients will benefit from re-induction approach. Accurate identification of chemotherapy refractory patients might allow the early incorporation of non-chemotherapy based protocols in the future.

Venetoclax in combination with FLAG-IDA-based protocol for patients with acute myeloid leukemia: a real-world analysis.

Venetoclax in combination with intensive therapies is explored in both the upfront and relapse/refractory (R/R) setting, and available data suggest that such regimens are effective albeit with added hematological and infectious toxicity. We conducted a multicenter retrospective cohort study of patients with acute myeloid leukemia (AML) treated with venetoclax in combination with FLAG-IDA protocol. Twenty-five patients were included in this analysis (median age 53.4 years). Most patients were treated for R/R AML (n = 24, 96%) with a median of one (range 0-3) previous lines of therapy and 44% of patients (n = 11) having prior allogeneic hematopoietic cell transplantation (HCT). Median follow-up was 10 (range, 4-26) months. Platelet and neutrophil recovery were observed at a median of 31 (95% CI 17.6-38.3) and 23 (95% CI 20-28) days, respectively. The most common adverse events were infectious (blood stream infections, 48% and invasive fungal infections, 32%). Thirty-day mortality was 12%. Composite complete remission (CRc) was 72% for the entire cohort and 91% in patients treated for post-HCT relapse. Incidences of relapse-free and overall survival at 12 months were 67% (95% CI 58-76%) and 50% (95% CI 31-69%), respectively. Real-world data show that the addition of venetoclax to FLAG-IDA protocol is effective in patients with high-risk AML, most notably in the post-HCT relapse setting. Prophylaxis and surveillance for infections are crucial.

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

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

Mesenchymal stroma/stem cells: Haematologists' friend or foe?

Mesenchymal stromal cells (MSCs) are non-haematopoietic cells found in fetal and adult organs, that play important roles in tissue repair, inflammation and immune modulation. MSCs residing in the bone marrow interact closely with haematopoietic cells and comprise an important component of the microenvironment supporting haematopoiesis, in both health and disease states. Since their identification in 1970, basic scientific and preclinical research efforts have shed light on the role of MSCs in the regulation of haematopoiesis and evoked interest in their clinical application in haematopoietic stem cell transplantation (HSCT) and malignant haematology. Over the last two decades, these research efforts have led to numerous clinical trials, which have established the safety of MSC therapy; however, the optimal mode of administration and the benefit remain inconclusive. In this paper, we will review the clinical experience with use of MSCs in HSCT for enhancement of engraftment, prevention and treatment of graft-versus-host disease and haemorrhagic cystitis. Then, we will discuss the contradictory evidence regarding tumour-promoting versus tumour-suppressing effects of MSCs in haematological malignancies, which may have relevance for future clinical applications.

The metabolic enzyme hexokinase 2 localizes to the nucleus in AML and normal haematopoietic stem and progenitor cells to maintain stemness.

Mitochondrial metabolites regulate leukaemic and normal stem cells by affecting epigenetic marks. How mitochondrial enzymes localize to the nucleus to control stem cell function is less understood. We discovered that the mitochondrial metabolic enzyme hexokinase 2 (HK2) localizes to the nucleus in leukaemic and normal haematopoietic stem cells. Overexpression of nuclear HK2 increases leukaemic stem cell properties and decreases differentiation, whereas selective nuclear HK2 knockdown promotes differentiation and decreases stem cell function. Nuclear HK2 localization is phosphorylation-dependent, requires active import and export, and regulates differentiation independently of its enzymatic activity. HK2 interacts with nuclear proteins regulating chromatin openness, increasing chromatin accessibilities at leukaemic stem cell-positive signature and DNA-repair sites. Nuclear HK2 overexpression decreases double-strand breaks and confers chemoresistance, which may contribute to the mechanism by which leukaemic stem cells resist DNA-damaging agents. Thus, we describe a non-canonical mechanism by which mitochondrial enzymes influence stem cell function independently of their metabolic function.