Venetoclax and hypomethylating agents in critically ill patients with newly diagnosed acute myeloid leukaemia.

Venetoclax (VEN) in combination with hypomethylating agents (HMAs) is considered the standard of treatment for individuals with newly diagnosed acute myeloid leukaemia (AML) who are ineligible for intensive chemotherapy. We conducted a retrospective analysis that encompassed 16 critically ill patients newly diagnosed with AML who were admitted to the intensive care unit (ICU) and received the VEN and HMA regimen. Among them, 13 were primary AML, and three were MDS-transformed AML. The mean Acute Physiology and Chronic Health Evaluation II (APACHE II) score was 18.9, and the mean sepsis-related organ failure assessment score (SOFA) was 6.2. The average length of the ICU stay was 27.3 days. The median duration of VEN administration was 16 days. After the first course of VEN + HMA, 12 cases (75%) achieved complete remission (CR) or CR with incomplete haematological recovery (CRi). Among the five patients harbouring TP53 mutations, the overall response rate (ORR) was 90%. All patients experienced grade 3-4 haematological adverse events (AEs). With a median follow-up of 9.5 months (range: 0.5-23), the overall survival (OS) rate was 43.75%. TP53-wild patients and CR state after the first course of VEN-HMA indicated better survival. The combination of VEN and HMA has demonstrated a significantly elevated therapeutic response rate in newly diagnosed AML patients with critical illness.

Clonal evolution from B-cell acute lymphoblastic leukemia with BCR::ABL1 multilineage involvement to acute myeloid leukemia after multiple anti-CD19 chimeric antigen receptor T-cell therapy.

Not available.

Recent progress in chimeric antigen receptor therapy for acute myeloid leukemia.

Although CAR-T cell therapy has been particularly successful as a treatment for B cell malignancies, effectively treating acute myeloid leukemia with CAR remains a greater challenge. Multiple preclinical studies and clinical trials are underway, including on AML-related surface markers that CAR-T cells can target, such as CD123, CD33, NKG2D, CLL1, CD7, FLT3, Lewis Y and CD70, all of which provide opportunities for developing CAR-T therapies with improved specificity and efficacy. We also explored specific strategies for CAR-T cell treatment of AML, including immune checkpoints, suicide genes, dual targeting, genomic tools and the potential for universal CAR. In addition, CAR-T cell therapy for AML still has certain risks and challenges, including cytokine release syndrome (CRS) and haematotoxicity. Despite these challenges, as a new targeting method for AML treatment, CAR-T cell therapy still has great prospects. Ongoing research aims to further optimize this treatment mode.

Mutation spectrum of FLT3 and significance of non-canonical FLT3 mutations in haematological malignancy.

Fms-like tyrosine kinase 3 (FLT3) is frequently mutated in haematological malignancies. Although canonical FLT3 mutations including internal tandem duplications (ITDs) and tyrosine kinase domains (TKDs) have been extensively studied, little is known about the clinical significance of non-canonical FLT3 mutations. Here, we first profiled the spectrum of FLT3 mutations in 869 consecutively newly diagnosed acute myeloid leukaemia (AML), myelodysplastic syndrome and acute lymphoblastic leukaemia patients. Our results showed four types of non-canonical FLT3 mutations depending on the affected protein structure: namely non-canonical point mutations (NCPMs) (19.2%), deletion (0.7%), frameshift (0.8%) and ITD outside the juxtamembrane domain (JMD) and TKD1 regions (0.5%). Furthermore, we found that the survival of patients with high-frequency (>1%) FLT3-NCPM in AML was comparable to those with canonical TKD. In vitro studies using seven representative FLT3-deletion or frameshift mutant constructs showed that the deletion mutants of TKD1 and the FLT3-ITD mutant of TKD2 had significantly higher kinase activity than wild-type FLT3, whereas the deletion mutants of JMD had phosphorylation levels comparable with wild-type FLT3. All tested deletion mutations and ITD were sensitive to AC220 and sorafenib. Collectively, these data enrich our understanding of FLT3 non-canonical mutations in haematological malignancies. Our results may also facilitate prognostic stratification and targeted therapy of AML with FLT3 non-canonical mutations.

Development of a scoring system for predicting primary resistance to venetoclax plus hypomethylating agents (HMAs) in acute myeloid leukemia patients.

In recent years, one of the most promising advances in the treatment of acute myeloid leukemia (AML) is the combination of a hypomethylating agent (HMA) with the BCL2 inhibitor venetoclax (VEN). To better understand the key factors associated with the response of VEN plus HMA, 212 consecutive AML patients were retrospectively recruited to establish and validate a scoring system for predicting the primary resistance to VEN-based induced therapy. All AML patients were divided randomly into a training set (n = 155) and a validation set (n = 57). Factors were selected using a multivariate logistic regression model, including FAB-M5, myelodysplastic syndrome-secondary acute myeloid leukemia (MDS-sAML), RUNX1-RUNX1T1 and FLT3-ITD mutation (FLT3-ITDm). A nomogram was then constructed including all these four predictors. The nomogram both presented a good performance of discrimination and calibration, with a C-index of 0.770 and 0.733 in the training and validation set. Decision curve analysis also indicated that the nomogram was feasible to make beneficial decisions. Eventually a total scoring system of 8 points was developed, which was divided into three risk groups: low-risk (score 0-2), medium-risk (score 3-4), and high-risk (score 5-8). There was a significant difference in the nonremission (NR) rate of these three risk groups (22.8% vs. 60.0% vs. 77.8%, p < 0.001). After adjustment of the other variables, patients in medium- or high-risk groups also presented a worse event-free survival (EFS) than that in the low-risk group (hazard ratio [HR] = 1.62, p = 0.03). In conclusion, we highlighted the response determinants of AML patients receiving a combination therapy of VEN plus HMAs. The scoring system can be used to predict the resistance of VEN, providing better guidance for clinical treatment.

Chidamide: Targeting epigenetic regulation in the treatment of hematological malignancy.

Epigenetic alterations frequently participate in the onset of hematological malignancies. Histone deacetylases (HDACs) are essential for regulating gene transcription and various signaling pathways. Targeting HDACs has become a novel treatment option for hematological malignancies. Chidamide is the first oral selective HDAC inhibitor for HDAC1, HDAC2, HDAC3, and HDAC10 and was first approved for the treatment of R/R peripheral T-cell lymphoma by the China Food and Drug Administration in 2014. Chidamide was also approved under the name Hiyasta (HBI-8000) in Japan in 2021. In vitro studies revealed that chidamide could inhibit proliferation and induce apoptosis via cell cycle arrest and the regulation of apoptotic proteins. In clinical studies, chidamide was also efficacious in multiple myeloma, acute leukemia and myelodysplastic syndrome. This review includes reported experimental and clinical data on chidamide monotherapy or chidamide treatment in combination with chemotherapy for various hematological malignancies, offering a rationale for the renewed exploration of this drug.

Comparing the efficacy of salvage regimens for relapsed/refractory B-cell acute lymphoblastic leukaemia: a systematic review and network meta-analysis.

The complete remission (CR) rate and overall survival (OS) of relapsed/refractory (R/R) B-cell acute lymphoblastic leukaemia (B-ALL) are not satisfactory. The available salvage regimens include standard chemotherapy, inotuzumab ozogamicin, blinatumomab and cluster of differentiation (CD)19 chimeric antigen receptor T cells (CAR T), and the NCCN guidelines recommend all of these therapies with no preference. Dual CD19/CD22 CAR T-cells have emerged as new treatments and have shown some efficacy, with high CR rates and preventing CD19-negative relapse. However, direct comparisons of the CR rate and long-term survival among the different salvage therapies are lacking. Databases including PubMed, Embase, Web of Science and Cochrane were searched from inception to January 31, 2022, for relevant studies. The outcomes of interest were complete remission/complete remission with incomplete haematologic recovery (CR/CRi) rates and 1-year overall survival (OS) rates. Odds ratios (ORs) were generated for binary outcomes, and the mean difference (MD) was generated for consecutive outcomes by network meta-analysis. CD19 CAR T-cells demonstrated a significantly better effect in improving the CR/CRi rate than blinatumomab (OR = 8.32, 95% CI: 1.18 to 58.44) and chemotherapy (OR = 16.4, 95% CI: 2.76 to 97.45). In terms of OS, CD19 CAR T-cells and dual CD19/CD22 CAR T-cells both had a higher 1-year OS rate than blinatumomab, inotuzumab ozogamicin and chemotherapy. There was no significant difference between CD19 CAR T-cells and dual CD19/CD22 CAR T-cells in terms of 1-year OS and CR/CRi rates. CD19 CAR T-cells are effective in inducing CR, and CD19 CAR T-cells and dual CD19/CD22 CAR T-cells show benefits for overall survival. More high-quality randomized controlled trials and longer follow-ups are needed to confirm and update the results of this analysis in the future.

Targeted therapy and immunotherapy for T cell acute lymphoblastic leukemia/lymphoma.

T cell acute lymphoblastic leukemia/lymphoma (T-ALL/LBL) is an aggressive malignancy of progenitor T cells. Despite significant improvements in survival of T-ALL/LBL over the past decades, treatment of relapsed and refractory T-ALL (R/R T-ALL/LBL) remains extremely challenging. The prognosis of R/R T-ALL/LBL patients who are intolerant to intensive chemotherapy remains poor. Therefore, innovative approaches are needed to further improve the survival of R/R T-ALL/LBL patients. With the widespread use of next-generation sequencing in T-ALL/LBL, a range of new therapeutic targets such as NOTCH1 inhibitors, JAK-STAT inhibitors, and tyrosine kinase inhibitors have been identified. These findings led to pre-clinical studies and clinical trials of molecular targeted therapy in T-ALL/LBL. Furthermore, immunotherapies such as CD7 CAR T cell therapy and CD5 CAR T cell therapy have shown profound response rate in R/R T-ALL/LBL. Here, we review the progress of targeted therapies and immunotherapies for T-ALL/LBL, and look at the future directions and challenges for the further use of these therapies in T-ALL/LBL.

Rapid molecular response to dasatinib in Ph-like acute lymphoblastic leukemia patients with ABL1 rearrangements: case series and literature review.

Philadelphia chromosome-like acute lymphoblastic leukemia (Ph-like ALL) is a high-risk subtype with a poor prognosis under conventional chemotherapy. Ph-like ALL has a similar gene expression profile to Philadelphia chromosome-positive (Ph+) ALL, but is highly heterogeneous in terms of genomic alterations. Approximately 10-20% of patients with Ph-like ALL harbor ABL class (e.g. ABL1, ABL2, PDGFRB, and CSF1R) rearrangements. Additional genes that form fusion genes with ABL class genes are still being researched. These aberrations result from rearrangements including chromosome translocations or deletions and may be targets of tyrosine kinase inhibitors (TKIs). However, due to the heterogeneity and rarity of each fusion gene in clinical practice, there is limited data on the efficacy of tyrosine kinase inhibitors. Here, we report three cases of Ph-like B-ALL with ABL1 rearrangements treated with the dasatinib backbone for the CNTRL::ABL1, LSM14A::ABL1, and FOXP1::ABL1 fusion genes. All three patients achieved rapid and profound remission with no significant adverse events. Our findings suggest that dasatinib is a potent TKI for the treatment of ABL1-rearranged Ph-like ALL and can be used as a first-line treatment option for such patients.

Integrative genomic and transcriptomic profiling reveals distinct molecular subsets in adult mixed phenotype acute leukemia.

Mixed phenotype acute leukemia (MPAL) is a subtype of leukemia in which lymphoid and myeloid markers are co-expressed. Knowledge regarding the genetic features of MPAL is lacking due to its rarity and heterogeneity. Here, we applied an integrated genomic and transcriptomic approach to explore the molecular characteristics of 176 adult patients with MPAL, including 86 patients with T-lymphoid/myeloid MPAL (T/My MPAL-NOS), 42 with Ph+ MPAL, 36 with B-lymphoid/myeloid MPAL (B/My MPAL-NOS), 4 with t(v;11q23), and 8 with MPAL, NOS, rare types. Genetically, T/My MPAL-NOS was similar to B/T MPAL-NOS but differed from Ph+ MPAL and B/My MPAL-NOS. T/My MPAL-NOS exhibited higher CEBPA, DNMT3A, and NOTCH1 mutations. Ph+ MPAL demonstrated higher RUNX1 mutations. B/T MPAL-NOS showed higher NOTCH1 mutations. By integrating next-generation sequencing and RNA sequencing data of 89 MPAL patients, we defined eight molecular subgroups (G1-G8) with distinct mutational and gene expression characteristics. G1 was associated with CEBPA mutations, G2 and G3 with NOTCH1 mutations, G4 with BCL11B rearrangement and FLT3 mutations, G5 and G8 with BCR::ABL1 fusion, G6 with KMT2A rearrangement/KMT2A rearrangement-like features, and G7 with ZNF384 rearrangement/ZNF384 rearrangement-like characteristics. Subsequently, we analyzed single-cell RNA sequencing data from five patients. Groups G1, G2, G3, and G4 exhibited overexpression of hematopoietic stem cell disease-like and common myeloid progenitor disease-like signatures, G5 and G6 had high expression of granulocyte-monocyte progenitor disease-like and monocyte disease-like signatures, and G7 and G8 had common lymphoid progenitor disease-like signatures. Collectively, our findings indicate that integrative genomic and transcriptomic profiling may facilitate more precise diagnosis and develop better treatment options for MPAL.

Ruxolitinib reduces severe CRS response by suspending CAR-T cell function instead of damaging CAR-T cells.

The therapeutic effect of CAR-T is often accompanied by sCRS, which is the main obstacle to the promotion of CAR-T therapy. The JAK1/2 inhibitor ruxolitinib has recently been confirmed as clinically effective in maintaining control over sCRS, however, its mechanism remains unclear. In this study, we firstly revealed that ruxolitinib significantly inhibited the proliferation of CAR-T cells without damaging viability, and induced an efficacy-favored differentiation phenotype. Second, ruxolitinib reduced the level of cytokine release not only from CAR-T cells, but also from other cells in the immune system. Third, the cytolytic activity of CAR-T cells was restored once the ruxolitinib was removed; however, the cytokines released from the CAR-T cells maintained an inhibited state to some degree. Finally, ruxolitinib significantly reduced the proliferation rate of CAR-T cells in vivo without affecting the therapeutic efficacy after withdrawal at the appropriate dose. We demonstrated pre-clinically that ruxolitinib interferes with both CAR-T cells and the other immune cells that play an important role in triggering sCRS reactions. This work provides useful and important scientific data for clinicians on the question of whether ruxolitinib has an effect on CAR-T cell function loss causing CAR-T treatment failure when applied in the treatment of sCRS, the answer to which is of great clinical significance.

PRMT1-mediated FLT3 arginine methylation promotes maintenance of FLT3-ITD+ acute myeloid leukemia.

The presence of FMS-like receptor tyrosine kinase-3 internal tandem duplication (FLT3-ITD) mutations in patients with acute myeloid leukemia (AML) is associated with poor clinical outcome. FLT3 tyrosine kinase inhibitors (TKIs), although effective in kinase ablation, do not eliminate primitive FLT3-ITD+ leukemia cells, which are potential sources of relapse. Thus, understanding the mechanisms underlying FLT3-ITD+ AML cell persistence is essential to devise future AML therapies. Here, we show that expression of protein arginine methyltransferase 1 (PRMT1), the primary type I arginine methyltransferase, is increased significantly in AML cells relative to normal hematopoietic cells. Genome-wide analysis, coimmunoprecipitation assay, and PRMT1-knockout mouse studies indicate that PRMT1 preferentially cooperates with FLT3-ITD, contributing to AML maintenance. Genetic or pharmacological inhibition of PRMT1 markedly blocked FLT3-ITD+ AML cell maintenance. Mechanistically, PRMT1 catalyzed FLT3-ITD protein methylation at arginine 972/973, and PRMT1 promoted leukemia cell growth in an FLT3 methylation-dependent manner. Moreover, the effects of FLT3-ITD methylation in AML cells were partially due to cross talk with FLT3-ITD phosphorylation at tyrosine 969. Importantly, FLT3 methylation persisted in FLT3-ITD+ AML cells following kinase inhibition, indicating that methylation occurs independently of kinase activity. Finally, in patient-derived xenograft and murine AML models, combined administration of AC220 with a type I PRMT inhibitor (MS023) enhanced elimination of FLT3-ITD+ AML cells relative to AC220 treatment alone. Our study demonstrates that PRMT1-mediated FLT3 methylation promotes AML maintenance and suggests that combining PRMT1 inhibition with FLT3 TKI treatment could be a promising approach to eliminate FLT3-ITD+ AML cells.

Impact of disease status at allogeneic stem cell transplantation on adolescent and young adult patients with early T-cell precursor acute lymphoblastic leukemia.

Early T-cell precursor (ETP) acute lymphoblastic leukemia (ALL) is an aggressive subset of T-cell ALL, and the role of allogeneic hematopoietic stem cell transplantation (allo-HSCT) in adolescent and young adult (AYA) patients has not been sufficiently described. We retrospectively analysed the data of 30 AYA patients (19 in first complete remission [CR1], 3 in CR2, and 8 with active disease) with ETP-ALL who underwent myeloablative allogeneic hematopoietic stem cell transplantation (allo-HSCT) from HLA-matched related, n = 2, unrelated, n = 5, or HLA-haploidentical related, n = 23 donors with an emphasis on the impact of disease status on the outcomes of transplant. The stem cell source was unmanipulated G-CSF mobilized bone marrow or peripheral blood stem cells. All patients achieved neutrophil engraftment with full donor chimerism. The cumulative incidences of grade II to IV acute graft-versus-host disease (GVHD) and chronic GVHD at 2 years were 37% and 33%, respectively. Overall, 16 patients died. The causes of death were relapse (8 patients), infection (4 patients) and GVHD (4 patients). The estimated 2-year overall survival (OS) and leukemia-free survival (LFS) for the whole cohort were 47.8% and 46.2%, respectively. Patients transplanted in CR1/2 had significantly better 2-year OS and LFS than patients with active disease (61.7% vs. 12.5%, p = 0.02; and 58.3% vs. 12.5%, p = 0.04, respectively). There was a trend toward an inferior OS rate in those patients in CR1 with chemoresistance or in CR2 compared with patients in CR1 with chemosensitivity, although this did not reach statistical significance. Our data support allo-HSCT, especially from HLA-haploidentical donors as an effective therapeutic strategy in AYA patients with ETP-ALL and disease status was significantly associated with survival in these patients.

Central Nervous System Complications after Allogeneic Hematopoietic Stem Cell Transplantation in Children.

Central nervous system complications (CNSCs) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) are common and may be a significant source of morbidity and mortality. We performed a retrospective study of 153 pediatric patients who underwent allo-HSCT to determine CNSC type, incidence, and impact on survival. A total of 34 patients (22.2%) developed CNSCs. The cumulative incidence of CNSCs at 100 days and 3 years was 18.30 and 22.73%, respectively. The most common CNSC was calcineurin inhibitor (CNI)-associated neurotoxicity (50.0%). Risk factors for CNSCs were the time from diagnosis to HSCT ≥4.8 months (p = 0.032) and the development of acute graft-versus-host disease (aGVHD) grade III-IV (p = 0.002). CNSCs after allo-HSCT negatively impacted overall survival (hazard ratio [HR] 1.97, p = 0.043) and nonrelapse mortality (HR 4.84, p < 0.001). In conclusion, CNSCs after allo-HSCT are associated with poor outcomes; patients with severe aGVHD and/or late transplantation should be given more attention.

Pattern and prognostic value of FLT3-ITD mutations in Chinese de novo adult acute myeloid leukemia.

FMS-like tyrosine kinase 3 (FLT3) is one of the most frequently mutated genes in hematological malignancies. FLT3 internal tandem duplication (FLT3-ITD) mutations located in juxtamembrane domain (JMD) and tyrosine kinase domain 1 (TKD1) regions account for two-thirds of all FLT3 mutations. The outcome of patients remains unsatisfactory, with low survival rates. It is not yet known whether the different mutations within the FLT3 gene are all associated with patient outcome. In addition, the cause of FLT3-ITD in-frame duplication events remains unknown. Although there are some published studies investigating the FLT3-ITD mutation and its clinical implications in Chinese acute myeloid leukemia (AML) patients, sample sizes tend to be small and detailed molecular profiles of FLT3 mutations are lacking in these studies. In our study, 227 FLT3-ITD sequences were analyzed from 227 Chinese de novo AML patients. ITD were next classified into 3 types based on molecular profiles of insertion DNA sequences: DNA complete duplication (type I), DNA partial duplication (type II) and complete random sequence (type III). From the 154 patients, we confirmed that high ITD allelic ratio (≥.5) and allogeneic stem cell transplant treatment under CR1 are independent prognostic factors. We also presented evidence that ITD integration sites in the hinge region or beta1-sheet region are an unfavorable prognostic factor in adult AML patients with FLT3-ITD mutations. These findings may help to decipher the mechanisms of FLT3-ITD in-frame duplication events and stratify patients when considering different therapeutic combinations.

Effects of preemptive interferon-α monotherapy in acute leukemia patients with relapse tendency after allogeneic hematopoietic stem cell transplantation: a case-control study.

Interferon-α (IFN-α) inhibits tumor growth and mimics graft-versus-leukemia after allogeneic hematopoietic stem cell transplantation (allo-HSCT). In the current case-control study, we compared treatment responses in acute leukemia patients with relapse tendency post-allo-HSCT receiving preemptive IFN-α after withdrawal of immunosuppressants (n = 31) vs. receiving no IFN-α (n = 67). In the IFN-α group, 25 patients responded to the treatment without progressing to hematological relapse. In the non-IFN-α group, only 22 patients responded to the treatment. The response rate differed significantly (80.6 vs. 32.8%, P < 0.001). The 2-year cumulative incidence of relapse was 31.6 and 61.2% in the IFN-α and the non-IFN groups, respectively (P = 0.006). The 2-year leukemia-free survival and overall survival rate was 57.4 vs. 28.4% (P < 0.001) and 67.6 vs. 32.9% (P = 0.001), respectively. Among the 31 patients in the IFN-α group, 18 patients (58.1%) developed graft-versus-host disease (GVHD): 6 acute and 12 limited chronic GVHD. Patients who developed GVHD had higher treatment response rate than patients without GVHD (88.9 vs. 53.8%, P = 0.022). In conclusion, preemptive IFN-α therapy is a safe and effective treatment to prevent disease progression in high-risk patients with relapse tendency post-allo-HSCT.