Investigations of the prognostic value of RUNX1 mutation in acute myeloid leukemia patients: Data from a real-world study.

RUNX1 is one of the recurrent mutated genes in newly diagnosed acute myeloid leukemia (AML). Although historically recognized as a provisional distinct entity, the AML subtype with RUNX1 mutations (AML-RUNX1mut) was eliminated from the 2022 WHO classification system. To gain more insight into the characteristics of AML-RUNX1mut, we retrospectively analyzed 1065 newly diagnosed adult AML patients from the First Affiliated Hospital of Soochow University between January 2017 and December 2021. RUNX1 mutations were identified in 112 patients (10.5%). The presence of RUNX1 mutation (RUNX1mut) conferred a lower composite complete remission (CRc) rate (40.2% vs. 58.4%, P＜0.001), but no significant difference was observed in the 5-year overall survival (OS) rate (50.2% vs. 53.9%; HR=1.293; P=0.115) and event-free survival (EFS) rate (51.5% vs. 49.4%; HR=1.487, P=0.089), even within the same risk stratification. Multivariate analysis showed that RUNX1mut was not an independent prognostic factor for OS (HR=1.352, P=0.068) or EFS (HR=1.129, P=0.513). When patients were stratified according to induction regimen, RUNX1mut was an unfavorable factor for CRc both on univariate and multivariate analysis in patients receiving conventional chemotherapy, and higher risk stratification predicted worse OS. In those who received venetoclax plus hypomethylating agents, RUNX1mut was not predictive of CRc and comparable OS and EFS were seen between intermediate-risk and adverse-risk groups. The results of this study revealed that the impact of RUNX1mut is limited. Its prognostic value depended more on treatment and co-occurrent abnormalities. VEN-HMA may abrogate the prognostic impact of RUNX1, which merits a larger prospective cohort to illustrate.

Preemptive inotuzumab ozogamicin eradicated measurable residual disease in Ph-negative acute lymphoblastic leukemia relapsed post CD19 CART therapy.

There are no reports of application of inotuzumab ozogamicin (InO) for the treatment of MRD in r/r B-ALL. We firstly report the efficacy of InO for a patient experienced morphological relapse after HSCT and molecular relapse after CART therapy.

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.

Case Report: Blinatumomab therapy for the treatment of B-cell acute lymphoblastic leukemia patients with central nervous system infiltration.

The treatment of B-cell acute lymphoblastic leukemia (B-ALL) with central nervous system (CNS) involvement poses a significant clinical challenge because most chemotherapeutic agents exhibit weak permeability to the blood-brain barrier (BBB). In addition, current anti-CNS leukemia treatments often bring short or long-term complications. Immunotherapy including chimeric antigen T-cell therapy and bispecific antibody have shown profound treatment responses in relapsed/refractory B-ALL. However, there is a lack of data on the efficacy of bispecific antibody in treating B-ALL with CNS involvement. Here, we report two ALL patients with CNS leukemia who received blinatumomab. Case 1 was diagnosed with chronic myeloid leukemia in lymphoid blast phase. The patient developed CNS leukemia and bone marrow relapse during the treatment with dasatinib. Case 2 was diagnosed with B-ALL and suffered early hematologic relapse and cerebral parenchyma involvement. After treatment with one cycle of blinatumomab, both patients achieved complete remission in the bone marrow and CNS. Furthermore, this is the first report on the efficacy of blinatumomab in treating CNS leukemia with both of the cerebral spinal fluid and the cerebral parenchymal involvement. Our results suggest that blinatumomab might be a potential option for the treatment of CNS leukemia.

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.

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.

Decitabine in combination with fludarabine and cyclophosphamide as a lymphodepletion regimen followed by CD19/CD22 bispecific targeted CAR T-cell therapy significantly improves survival in relapsed/refractory B-ALL patients.

Relapse is a major limitation of chimeric antigen receptor (CAR) T-cell therapy. Here, we speculated that decitabine (DAC) in combination with fludarabine and cyclophosphamide (FC) as a lymphodepletion regimen may improve the efficacy of CD19/CD22 CAR T-cell therapy. Fourteen of 26 patients with relapsed/refractory B cell acute lymphoblastic leukemia (r/r B-ALL) without remission before lymphodepletion treatment were treated with DAC (total dose 100 mg/m2 in 3 days) followed by the FC regimen (DAC group), while twelve patients received the FC regimen (CON group). On Day 28 after CAR T-cells infusion, no significant differences in complete remission (CR) and minimal residual disease negative CR rates were found between both groups. However, there were significant differences in overall survival (OS) and leukemia-free survival (LFS) between two groups: 3-year OS, 92.3% (DAC) versus 41.7% (CON), P = 0.005 and 3-year LFS, 92.9% (DAC) versus 27.3% (CON), P < 0.001. There was no significant difference in the incidence of cytokine release syndrome between both groups. Median time to platelet and neutrophil counts recovery was similar in both groups. All adverse events were reversible and manageable. In conclusion, DAC in combination with the FC lymphodepletion regimen may be a new treatment option that can improve the efficacy of CAR T-cell therapy in r/r B-ALL.

Which one is better for refractory/relapsed acute B-cell lymphoblastic leukemia: Single-target (CD19) or dual-target (tandem or sequential CD19/CD22) CAR T-cell therapy?

CD19 chimeric antigen receptor (CAR) T-cell therapy has shown great success against B-cell acute lymphoblastic leukemia (B-ALL). Tandem and sequential CD19/CD22 dual-target CAR T-cell therapies have been developed to reduce the possibility of CD19-negative relapse; however, the superior strategy is still uncertain. This study screened 219 patients with relapsed/refractory B-ALL who were enrolled in clinical trials of either CD19 (NCT03919240) or CD19/CD22 CAR T-cell therapy (NCT03614858). The complete remission (CR) rates in the single CD19, tandem CD19/CD22, and sequential CD19/CD22 groups were 83.0% (122/147), 98.0% (50/51), and 95.2% (20/21), respectively (single CD19 vs. tandem CD19/CD22, P = 0.006). Patients with high-risk factors achieved a higher rate of CR in the tandem CD19/CD22 group than in the single CD19 group (100.0% vs. 82.4%, P = 0.017). Tandem CD19/CD22 CAR T-cell therapy was one of the significant favorable factors in the multivariate analysis of the CR rate. The incidence of adverse events was similar among the three groups. Multivariable analysis in CR patients showed that a low frequency of relapse, a low tumor burden, minimal residual disease-negative CR and bridging to transplantation were independently associated with better leukemia-free survival. Our findings suggested that tandem CD19/CD22 CAR T-cell therapy obtains a better response than CD19 CAR T-cell therapy and a similar response to sequential CD19/CD22 CAR T-cell therapy.

CAR-T cell therapy followed by allogenic hematopoietic stem cell transplantation yielded comparable outcome between Ph like ALL and other high-risk ALL.

It was previously believed that patients with Ph-like ALL had poorer prognosis compared with other B-ALL subgroups due to resistance to conventional chemotherapy and lack of targeted drugs. CAR-T therapy has been successfully applied in the treatment of relapsed and refractory B-ALL. Currently, there are few data on whether CAR-T therapy can alter the outcome of Ph-like ALL. Here we included 17 Ph-like, 23 Ph+ and 51 other B-ALL patients, who received autologous CAR T-cell therapy and subsequently allogenic stem cell transplantation. Patients in the Ph-like group and B-ALL-others group were younger that those in the Ph+ group (P=0.001). Ph-like and Ph+ ALL patients showed higher white blood cell counts at diagnosis (P=0.025). The percentage of patients with active disease before receiving CAR T-cells infusion was 64.7%, 39.1% and 62.7% in the Ph-like, Ph+ and B-ALL-others groups. The response rates to CAR-T therapy were 94.1% (16/17), 95.6% (22/23) and 98.0% (50/51) in the Ph-like, Ph+ and B-ALL-others groups. Measurable residual disease negative CR was achieved in 64.7% (11/17), 60.9% (14/23) and 54.9% (28/51) in the Ph-like, Ph+ and B-ALL-others groups, respectively. The estimated rates of 3-year overall survival (65.9%±16.5%, 59.7%±10.5% and 61.6%±7.3%, P=0.758) and 3-year relapse-free survival (59.8%±14.8%, 63.1%±10.5% and 56.3%±7.1%, P=0.764) were comparable among the Ph-like, Ph+ and B-ALL-others groups. Estimated 3-year cumulative relapse rate was 7.8%±0.6%, 23.4%±0.9% and 29.0%±0.4% (P=0.241). Our findings suggest that CART followed by allo-HSCT results in a comparable prognosis in Ph-like ALL and other high-risk B-ALL.Trial registration ClinicalTrials. gov, NCT03275493, Registered on September 7, 2017, prospectively registered and NCT03614858, Registered on August 3, 2018, prospectively registered.

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.

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.

Case report: CD38-directed CAR-T cell therapy: A novel immunotherapy targeting CD38- positive blasts overcomes TKI and chemotherapy resistance of myeloid chronic myeloid leukemia in blastic phase.

Resistance to tyrosine kinase inhibitor (TKI) is a tough problem in the treatment of chronic myeloid leukemia in blastic phase (CML-BP), which was often associated with acquired mutations in the kinase domain and not eliminating the leukemic stem cells. The efficacy of TKI or combination with chemotherapy in CML-BP remains unsatisfactory. Chimeric antigen receptor T (CAR-T) cell immunotherapy may overcome TKI and chemotherapy resistance. However, lack of ideal targetable antigens is a major obstacle for treating patients with myeloid malignancies. CD38 is known to be expressed on most (acute myeloid leukemia) AML cells, and its lack of expression on hematopoietic stem cells renders it as a potential therapeutic target for myeloid CML-BP. We develop a CD38-directed CAR-T cell therapy for AML, and two patients with myeloid CML-BP were enrolled (NCT04351022). Two patients, harboring E255K and T315I mutation in the ABL kinase domain, respectively, were resistant to multiple TKIs (imatinib, dasatinib, nilotinib, and ponatinib) and intensive chemotherapy. The blasts in the bone marrow of two patients exhibited high expression of CD38. After tumor reduction chemotherapy and lymphodepletion chemotherapy, 1 × 107 CAR-T-38 cells per kilogram of body weight were administered. They achieved minimal residual disease-negative and BCR::ABL1-negative complete remission and experienced grade II cytokine release syndrome manifesting as fever. Our data highlighted that CAR-T-38 cell therapy may overcome TKI and chemotherapy resistance in patients with myeloid CML-BP.

Efficacy and safety of decitabine combined with HAAG (homoharringtonine, aclarubicin, low-dose cytarabine and G-CSF) for newly diagnosed acute myeloid leukemia.

The 7 + 3 regimen is the front-line induction chemotherapy in patients with newly diagnosed acute myeloid leukemia, with a response rate of 60-80%. But it's not suitable for all patients especially old/unfit patients because of a higher treatment related toxicity. Therefore, safer and more effective induction therapies are required. In this retrospective study, 50 patients with newly diagnosed acute myeloid leukemia received decitabine combined with HAAG (homoharringtonine, aclarubicin, low-dose cytarabine and G-CSF) as induction chemotherapy. Complete remission (CR) rate was 96% (48/50) and overall response rate was 100%. Of note, All 7 patients harboring FLT3-ITD mutation achieved CR. The median overall survival (OS) was 40.0 months (range 2.0, 58.0). The OS at 1, 3, and 5 years were 75.3%, 54.2%, and 49.3%. The median relapse free survival (RFS) was 38.0 months (range 2.0, 58.0). The RFS at 1, 3, and 5 years were 67.3%, 48.9%, and 45.1%. The OS and RFS of patients who received hematopoietic stem cell transplantation (HSCT) were significantly higher than those who did not undergo HSCT (p=0.017; 0.016). The incidence of grade 3-4 neutropenia and thrombocytopenia was 84% and 88%. Meanwhile, the incidence of grade 3-4 infection and bleeding was only 16% and 6%. There was no early death. In conclusion, DAC+HAAG regimen is effective and well-tolerated as induction therapy in patients with newly diagnosed AML.