Leukemia最新文献

T-cell redirecting therapy (TCRT), specifically chimeric antigen receptor T-cell therapy (CAR T-cells) and bispecific T-cell engagers (TCEs) represent a remarkable advance in the treatment of multiple myeloma (MM). There are several products available around the world and several more in development targeting primarily B-cell maturation antigen (BCMA) and G protein–coupled receptor class C group 5 member D (GRPC5D). The relatively rapid availability of multiple immunotherapies brings the necessity to understand how a certain agent may affect the safety and efficacy of a subsequent immunotherapy so MM physicians and patients can aim at optimal sequential use of these therapies. The International Myeloma Working Group conveyed panel of experts to review patient and disease-related factors affecting efficacy and safety of immunotherapy, summarize existing information on sequencing therapy and provide a series of core recommendations.

Refractory disease and relapse are major challenges in acute myeloid leukemia (AML) therapy attributed to survival of leukemic stem cells (LSC). To target LSCs, antibody-drug conjugates (ADCs) provide an elegant solution, combining the specificity of antibodies with highly potent payloads. We aimed to investigate if FLT3-20D9h3-ADCs delivering either the DNA-alkylator duocarmycin (DUBA) or the microtubule-toxin monomethyl auristatin F (MMAF) can eradicate quiescent LSCs. We show here that DUBA more potently kills cell-cycle arrested AML cells compared to microtubule-targeting auristatins. Due to limited stability of 20D9h3-DUBA ADC in vivo, we analyzed both ADCs in advanced in vitro stem cell assays. 20D9h3-DUBA successfully eliminated leukemic progenitors in vitro in colony-forming unit and long-term culture initiating cell assays, both in patient cells and in patient-derived xenograft (PDX) cells. Further, it completely prevented engraftment of AML PDX leukemia-initiating cells in NSG mice. 20D9h3-MMAF had a similar effect in engraftment assays, but a less prominent effect in colony assays. Both ADCs did not affect healthy stem and progenitor cells at comparable doses providing the rationale for FLT3 as therapeutic LSC target. Collectively, we show that FLT3-directed ADCs with DUBA or MMAF have potent activity against AML LSCs and represent promising candidates for further clinical development.

In addition to biological factors, maternal exposures during pregnancy can contribute to leukemogenesis in offspring. We conducted a population-based cohort study in Sweden to investigate the association between risk of acute lymphoblastic leukemia (ALL) in offspring and maternal anthropometrics during pregnancy. A total of 2,961,435 live-born singletons during 1983–2018 were followed from birth to ALL diagnosis, end of age 18, or end of 2018. 1388 children were diagnosed with ALL (55.6% boys). We observed an increased risk of ALL among daughters of overweight/obese mothers in early pregnancy [Body mass index (BMI) ≥ 25 kg/m²; Standardized incidence ratio (SIR) = 1.4, 95% CI: 1.2–1.6] compared with the risk in daughters of mothers with normal BMI. This association was not found in their sons (SIR = 1.0, 95% CI: 0.9–1.1). Similar results were found for the association between ALL and maternal BMI before delivery. We did not find an association between low or high gestational weight gain (GWG) and risk of ALL (both SIRs = 1.0) in male/female offspring. These suggest that maternal overweight/obesity are important risk factors for childhood ALL in daughters, whereas GWG is not associated with risk of ALL. Further research on this mother-daughter association may shed light on a possible sex hormone/chromosome-related etiology of ALL.

Early T-cell Precursor Acute Lymphoblastic Leukemia (ETP-ALL) is an immature subtype of T-cell acute lymphoblastic leukemia (T-ALL) commonly show deregulation of the LMO2-LYL1 stem cell transcription factors, activating mutations of cytokine receptor signaling, and poor early response to intensive chemotherapy. Previously, studies of the Lmo2 transgenic mouse model of ETP-ALL identified a population of stem-like T-cell progenitors with long-term self-renewal capacity and intrinsic chemotherapy resistance linked to cellular quiescence. Here, analyses of Lmo2 transgenic mice, patient-derived xenografts, and single-cell RNA-sequencing data from primary ETP-ALL identified a rare subpopulation of leukemic stem cells expressing high levels of the cytokine receptor FLT3. Despite a highly proliferative state, these FLT3-overexpressing cells had long-term self-renewal capacity and almost complete resistance to chemotherapy. Chromatin immunoprecipitation and assay for transposase-accessible chromatin sequencing demonstrated FLT3 and its ligand may be direct targets of the LMO2 stem-cell complex. Media conditioned by Lmo2 transgenic thymocytes revealed an autocrine FLT3-dependent signaling loop that could be targeted by the FLT3 inhibitor gilteritinib. Consequently, gilteritinib impaired in vivo growth of ETP-ALL and improved the sensitivity to chemotherapy. Furthermore, gilteritinib enhanced response to the BCL2 inhibitor venetoclax, which may enable “chemo-free” treatment of ETP-ALL. Together, these data provide a cellular and molecular explanation for enhanced cytokine signaling in LMO2-driven ETP-ALL beyond activating mutations and a rationale for clinical trials of FLT3 inhibitors in ETP-ALL.

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematological disease originating from the malignant transformation of T-cell progenitors, caused by the accumulation of genetic aberrations. One-fifth of T-ALL patients are characterized by ectopic expression of the homeobox transcription factor TLX3. However, the role of TLX3 in T-ALL remains elusive, partly due to the lack of suitable study models. Strikingly, this TLX3-positive subgroup has a high frequency of FLT3 mutations, predominantly FLT3-ITD, in pediatric cases. To investigate this, we generated ex vivo cultured pro-T cells driven by the co-expression of TLX3 and FLT3-ITD, which conferred IL7 independent growth. This model allowed us to confirm that TLX3 expression and FLT3 signaling cooperate to transform T-cells and induce an oncogenic context. Data from this cell model, combined with gene expression data from TLX3 positive T-ALL cases, revealed a strong downregulation of the transcriptional repressor TLE4. Furthermore, TLE4 showed to have a repressive effect on ex vivo TLX3 T-ALL cell growth, likely caused by a partial reversal of the TLX3 transcriptional profile. In conclusion, we developed a TLX3+FLT3-ITD pro-T cell model and used it to illustrate that TLX3 directly represses TLE4 expression, which is beneficial for the oncogenic function of TLX3.

Expression of CD2, CD25 and/or CD30 in extracutaneous mast cells (MC) is a minor diagnostic criterion for systemic mastocytosis (SM) in the classification of the World Health Organization and International Consensus Classification. So far, it remains unknown whether expression of these antigens on MC is of prognostic significance in SM. We performed a retrospective multi-center study of patients with SM using the data set of the registry of the European Competence Network on Mastocytosis, including 5034 patients with various MC disorders. The percentage of CD2^-, CD25⁺ and/or CD30⁺ MC was considerably lower in patients with indolent SM compared to patients with advanced SM, including aggressive SM and MC leukemia. Whereas CD25 and CD30 expression in MC could not be associated with prognosis, we found that lack of CD2 expression in MC is associated with a significantly reduced overall survival (OS) in patients with SM (p < 0.0001). Lack of CD2 was also associated with the presence of extramedullary involvement affecting the spleen, liver, and/or lymph nodes (odds ratio 2.63 compared to SM with CD2⁺ MC). Together, lack of CD2 expression in MC is a prognostic marker and indicator of reduced OS and extramedullary disease expansion in patients with SM.

In the MAIA study (median follow-up, 56.2 months), daratumumab plus lenalidomide and dexamethasone (D-Rd) significantly improved progression-free survival (PFS) and overall survival versus lenalidomide and dexamethasone (Rd) alone in transplant-ineligible newly diagnosed multiple myeloma (NDMM). In this post hoc analysis of clinically important subgroups in MAIA (median follow-up, 64.5 months), transplant-ineligible patients with NDMM were randomized 1:1 to D-Rd or Rd. The primary endpoint was PFS; secondary endpoints included overall response rate (ORR) and measurable residual disease (MRD)–negativity rate (10^–5). PFS favored D-Rd versus Rd in most subgroups, including patients aged ≥75 years (HR, 0.59; 95% CI, 0.44–0.79), frail patients (HR, 0.64; 95% CI, 0.48–0.85), patients with high-risk cytogenetics (HR, 0.59; 95% CI, 0.44–0.80), and patients with isolated gain(1q21) (HR, 0.36; 95% CI, 0.19–0.67). ORRs, MRD-negativity rates, and sustained (≥12 months) MRD-negativity rates were higher with D-Rd versus Rd across subgroups. In patients aged ≥75 years, rates of grade 3/4 and serious treatment-emergent adverse events (TEAEs) were similar for D-Rd and Rd, but discontinuation due to TEAEs was lower for D-Rd. Results support use of D-Rd for high-risk patients, supporting D-Rd as a standard of care for transplant-ineligible NDMM. This trial was registered at www.clinicaltrials.gov as NCT02252172.