Mechanisms of action and resistance in histone methylation-targeted therapy.

Epigenomes enable the rectification of disordered cancer gene expression, thereby providing new targets for pharmacological interventions. The clinical utility of targeting histone H3 lysine trimethylation (H3K27me3) as an epigenetic hallmark has been demonstrated1-7. However, in actual therapeutic settings, the mechanism by which H3K27me3-targeting therapies exert their effects and the response of tumour cells remain unclear. Here we show the potency and mechanisms of action and resistance of the EZH1-EZH2 dual inhibitor valemetostat in clinical trials of patients with adult T cell leukaemia/lymphoma. Administration of valemetostat reduced tumour size and demonstrated durable clinical response in aggressive lymphomas with multiple genetic mutations. Integrative single-cell analyses showed that valemetostat abolishes the highly condensed chromatin structure formed by the plastic H3K27me3 and neutralizes multiple gene loci, including tumour suppressor genes. Nevertheless, subsequent long-term treatment encounters the emergence of resistant clones with reconstructed aggregate chromatin that closely resemble the pre-dose state. Acquired mutations at the PRC2-compound interface result in the propagation of clones with increased H3K27me3 expression. In patients free of PRC2 mutations, TET2 mutation or elevated DNMT3A expression causes similar chromatin recondensation through de novo DNA methylation in the H3K27me3-associated regions. We identified subpopulations with distinct metabolic and gene translation characteristics implicated in primary susceptibility until the acquisition of the heritable (epi)mutations. Targeting epigenetic drivers and chromatin homeostasis may provide opportunities for further sustained epigenetic cancer therapies.

An open-label, single-arm phase 2 trial of valemetostat for relapsed or refractory adult T-cell leukemia/lymphoma.

Adult T-cell leukemia/lymphoma (ATL) is an aggressive non-Hodgkin lymphoma with poor prognosis and few treatment options for patients with relapsed, recurrent, or refractory disease. We evaluated the efficacy and safety of valemetostat, a potent enhancer of zeste homolog 2 (EZH2) and EZH1 inhibitor, in treating relapsed or refractory (R/R) ATL. This multicenter phase 2 trial enrolled patients with R/R aggressive ATL (acute, lymphoma, unfavorable chronic type). Patients received valemetostat 200 mg/day orally until progressive disease or unacceptable toxicity. The primary end point was overall response rate (ORR) centrally assessed by an independent efficacy assessment committee (IEAC). Secondary end points included best response in disease compartments, duration of response (DOR), pharmacokinetics, and safety. Twenty-five patients (median age, 69.0 years) with a median of 3 prior lines of therapy were enrolled; 24 had prior mogamulizumab treatment. The primary end point was met with a centrally reviewed ORR of 48.0% (90% confidence interval [CI], 30.5-65.9), including 5 complete and 7 partial remissions. Patients pretreated with mogamulizumab had an ORR of 45.8% (4 complete and 7 partial remissions). IEAC-assessed median DOR was not reached (NR) (95% CI, 1.87 to NR; months). Treatment-emergent adverse events (TEAEs) were manageable. TEAEs that occurred in ≥20% of patients included thrombocytopenia, anemia, alopecia, dysgeusia, neutropenia, lymphopenia, leukopenia, decreased appetite, and pyrexia. Grade ≥3 TEAEs included thrombocytopenia, anemia, lymphopenia, leukopenia, and neutropenia. Valemetostat demonstrated promising efficacy and tolerability in heavily pretreated patients, warranting further investigation in treating R/R ATL. This trial was registered at www.clinicaltrials.gov as #NCT04102150.

Two novel high-risk adult B-cell acute lymphoblastic leukemia subtypes with high expression of CDX2 and IDH1/2 mutations.

The genetic basis of leukemogenesis in adults with B-cell acute lymphoblastic leukemia (B-ALL) is largely unclear, and its clinical outcome remains unsatisfactory. This study aimed to advance the understanding of biological characteristics, improve disease stratification, and identify molecular targets of adult B-ALL. Adolescents and young adults (AYA) (15 to 39 years old, n = 193) and adults (40 to 64 years old, n = 161) with Philadelphia chromosome-negative (Ph-) B-ALL were included in this study. Integrated transcriptomic and genetic analyses were used to classify the cohort into defined subtypes. Of the 323 cases included in the RNA sequencing analysis, 278 (86.1%) were classified into 18 subtypes. The ZNF384 subtype (22.6%) was the most prevalent, with 2 novel subtypes (CDX2-high and IDH1/2-mut) identified among cases not assigned to the established subtypes. The CDX2-high subtype (3.4%) was characterized by high expression of CDX2 and recurrent gain of chromosome 1q. The IDH1/2-mut subtype (1.9%) was defined by IDH1 R132C or IDH2 R140Q mutations with specific transcriptional and high-methylation profiles. Both subtypes showed poor prognosis and were considered inferior prognostic factors independent of clinical parameters. Comparison with a previously reported pediatric B-ALL cohort (n = 1003) showed that the frequencies of these subtypes were significantly higher in AYA/adults than in children. We delineated the genetic and transcriptomic landscape of adult B-ALL and identified 2 novel subtypes that predict poor disease outcomes. Our findings highlight the age-dependent distribution of subtypes, which partially accounts for the prognostic differences between adult and pediatric B-ALL.

Clinical and prognostic features of Langerhans cell histiocytosis in adults.

Langerhans cell histiocytosis (LCH) is a rare disease characterized by clonal expansion of CD1a+ CD207+ myeloid dendritic cells. The features of LCH are mainly described in children and remain poorly defined in adults; therefore, we conducted a nationwide survey to collect clinical data from 148 adult patients with LCH. The median age at diagnosis was 46.5 (range: 20-87) years with male predominance (60.8%). Among the 86 patients with detailed treatment information, 40 (46.5%) had single system LCH, whereas 46 (53.5%) had multisystem LCH. Moreover, 19 patients (22.1%) had an additional malignancy. BRAF V600E in plasma cell-free DNA was associated with a low overall survival (OS) rate and the risk of the pituitary gland and central nervous system involvement. At a median follow-up of 55 months from diagnosis, six patients (7.0%) had died, and the four patients with LCH-related death did not respond to initial chemotherapy. The OS probability at 5 years post-diagnosis was 90.6% (95% confidence interval: 79.8-95.8). Multivariate analysis showed that patients aged ≥60 years at diagnosis had a relatively poor prognosis. The probability of event-free survival at 5 years was 52.1% (95% confidence interval: 36.6-65.5), with 57 patients requiring chemotherapy. In this study, we first revealed the high rate of relapse after chemotherapy and mortality of poor responders in adults as well as children. Therefore, prospective therapeutic studies of adults with LCH using targeted therapies are needed to improve outcomes in adults with LCH.

Circulating cell-free DNA in the peripheral blood plasma of patients is an informative biomarker for multiple myeloma relapse.

BACKGROUND: Multiple myeloma (MM) is an incurable hematological malignancy. Despite the introduction of several novel drugs, most patients relapse. Biomarkers to identify the early signs of relapse will make it possible to adjust the therapeutic strategy before the disease worsens. Although understanding genetic changes is important for the treatment of MM, currently known biomarkers of relapse, including serum free-light chains and monoclonal paraproteins, are not associated with genetic changes. METHODS: We therefore performed a multicenter study to examine the usefulness of circulating cell-free DNA (cfDNA) present in the peripheral blood (PB) plasma of patients as a biomarker for MM relapse. RESULTS: We identified several driver mutations by combined analysis of next-generation sequencing and existing databases of candidate oncogenes. Furthermore, relapse was detected more sensitively by monitoring the circulating cfDNA with these driver mutations than by conventional serum free-light chain examination. CONCLUSION: These results suggest the potential utility of cfDNA in the PB plasma of patients as a relevant early biomarker for MM relapse.

[Cooccurrence of classic Hodgkin lymphoma and multiple myeloma].

Although classic Hodgkin's lymphoma (CHL) sometimes develops after treatment for multiple myeloma (MM), simultaneous diagnosis of both malignancies is extremely rare without previous treatment history. Here we describe a case of a 54-year-old female who complained of left cervical lymphadenopathy. Biopsy specimen from the left cervical lymph node revealed mixed-cellularity CHL. Bone marrow aspirate comprised 10.3% plasma cells. She was diagnosed with MM due to involved: uninvolved serum free light chain ratio of >100. She achieved complete response for CHL after 4 cycles of doxorubicin, bleomycin, vinblastine, and dacarbazine chemotherapy along with 30 Gy of involved-field radiotherapy. Three years later, bortezomib, lenalidomide, and dexamethasone (VRd-lite) therapy was initiated for MM. Severe neutropenia during her 1st cycle prompted a dosage reduction of lenalidomide and bortezomib. Partial response was achieved after 4 cycles of VRd-lite followed by high-dose melphalan/autologous stem cell transplantation. No severe adverse events were recorded. This was followed by 4 cycles of carfilzomib, lenalidomide, and dexamethasone therapy, which resulted in complete remission. As the number of elderly people increases, multiple myeloma patients with previous history of other malignancies would increase. Our case has shown that VRd-lite therapy may be suitable for those patients.

High Prevalence of Left Ventricular Non-Compaction and Its Effect on Chemotherapy-Related Cardiac Dysfunction in Patients With Hematological Diseases.

BACKGROUND: Recent progress in chemotherapy has prolonged the survival of patients with hematological diseases, but has also increased the number of patients with chemotherapy-related cardiac dysfunction (CTRCD). However, the causes of individual variations and risk factors for CTRCD have yet to be fully elucidated.Methods and Results:Consecutive echocardiograms of 371 patients were retrospectively evaluated for the presence of left ventricular (LV) non-compaction (LVNC). Individual LV ejection fraction (LVEF) outcome estimates were made using bivariate linear regression with log-transformed duration Akaike information criterion (AIC) model fitting. The prevalence of LVNC was 6-fold higher in patients with hematological diseases than in those with non-hematological diseases (12% vs. 2%; risk ratio 6.1; 95% confidence interval [CI] 2.0, 18.2). Among patients with hematological diseases, the ratio of myeloid diseases was significantly higher in the group with LVNC (P=0.031). Deterioration of LVEF was more severe in patients with than without LVNC (-14.4 percentage points/year [95% CI -21.0, -7.9] vs. -4.6 percentage points/year [95% CI -6.8, -2.4], respectively), even after multivariate adjustment for baseline LVEF, background disease distributions, cumulative anthracycline dose, and other baseline factors. CONCLUSIONS: LVNC is relatively prevalent in patients with hematological diseases (particularly myeloid diseases) and can be one of the major risk factors for CTRCD. Detailed cardiac evaluations including LVNC are recommended for patients undergoing chemotherapy.

CD4+ CADM1+ cell percentage predicts disease progression in HTLV-1 carriers and indolent adult T-cell leukemia/lymphoma.

We recently took advantage of the universal expression of cell adhesion molecule 1 (CADM1) by CD4+ cells infected with HTLV-1 and the downregulation of CD7 expression that corresponds with the oncogenic stage of HTLV-1-infected cells to develop a flow cytometric system using CADM1 versus CD7 plotting of CD4+ cells. We risk-stratified HTLV-1 asymptomatic carriers (AC) and indolent adult T-cell leukemia/lymphoma (ATL) cases based on the CADM1+ percentage, in which HTLV-1-infected clones are efficiently enriched. AC and indolent ATL cases were initially classified according to their CADM1+ cell percentage. Follow-up clinical and flow cytometric data were obtained for 71 cases. In G1 (CADM1+ ≤ 10%) and G2 (10% < CADM1+ ≤ 25%) cases, no apparent clinical disease progression was observed. In G3 (25% < CADM1+ ≤ 50%) cases, five out of nine (55.5%) cases progressed from AC to smoldering-type ATL. In G4 (50% < CADM1+ ) cases, the cumulative incidence of receiving systemic chemotherapy at 3 years was 28.4%. Our results indicate that the percentage of the CD4+ CADM1+ population predicts clinical disease progression: G1 and G2 cases, including AC cases, are stable and considered to be at low risk; G3 cases, including advanced AC cases and smoldering-type ATL cases based on the Shimoyama criteria, are considered to have intermediate risk; and G4 cases, which are mainly indolent ATL cases, are unstable and at high risk of acute transformation.

[Autologous peripheral blood stem cell transplantation for double-refractory myeloma with K-RAS and N-RAS mutations].

The prognosis of multiple myeloma (MM) has been improved due to the introduction of novel agents like proteasome inhibitors and immunomodulatory drugs (IMiDs). However, some cases are refractory to the use of novel agents, and the prognosis of such cases is poor. A 53-year-old male was diagnosed with MM and categorized as follows: Bence-Jones protein lambda type MM, Durie-Salmon IIIA, international staging system (ISS) stage II, and revised ISS stage II. Mutations in K-RAS and IGH/FGFR3 translocation were detected at diagnosis. His tumor was refractory to seven therapeutic regimens including bortezomib, IMiDs (lenalidomide, thalidomide, pomalidomide), conventional chemotherapy, and radiation therapy. N-RAS mutations, CKS1B gains, and C-MYC split signals were detected after treatment. We performed high-dose melphalan/autologous stem cell transplantation (HD-MEL/ASCT) as a salvage therapy and achieved very good partial response. The correlation between K-RAS mutations and poor prognosis or between N-RAS mutations and reduced sensitivity to bortezomib is reported. However, RAS mutations are reported as a favorable factor for HD-MEL/ASCT. In general, mutations of both the K-RAS and N-RAS are known to be mutually exclusive. This rare MM case has mutations in both K-RAS and N-RAS, and the possible relevance of these mutations to both the refractoriness to novel therapies and sensitivity to HD-MEL/ASCT is suggested.

Vincristine-induced paralytic ileus during induction therapy of treatment protocols for acute lymphoblastic leukemia in adult patients.

Vincristine (VCR) is an important drug used in the treatment of acute lymphoblastic leukemia (ALL). VCR-induced neurotoxicity can manifest as peripheral neuropathy, constipation, or paralytic ileus. While there are some case reports describing VCR-induced paralytic ileus (VIPI) in pediatric ALL, there are fewer publication on adult ALL patients. Therefore, we retrospectively investigated VIPI during induction therapy of treatment protocols for ALL in 19 adult patients. The incidence of VIPI was 32%. VIPI was significantly increased in patients receiving concomitant itraconazole (ITCZ) (p = 0.04). We recommend avoidance of the combination of VCR and ITCZ.

MicroRNA-126-mediated control of cell fate in B-cell myeloid progenitors as a potential alternative to transcriptional factors.

Lineage specification is thought to be largely regulated at the level of transcription, where lineage-specific transcription factors drive specific cell fates. MicroRNAs (miR), vital to many cell functions, act posttranscriptionally to decrease the expression of target mRNAs. MLL-AF4 acute lymphocytic leukemia exhibits both myeloid and B-cell surface markers, suggesting that the transformed cells are B-cell myeloid progenitor cells. Through gain- and loss-of-function experiments, we demonstrated that microRNA 126 (miR-126) drives B-cell myeloid biphenotypic leukemia differentiation toward B cells without changing expression of E2A immunoglobulin enhancer-binding factor E12/E47 (E2A), early B-cell factor 1 (EBF1), or paired box protein 5, which are critical transcription factors in B-lymphopoiesis. Similar induction of B-cell differentiation by miR-126 was observed in normal hematopoietic cells in vitro and in vivo in uncommitted murine c-Kit(+)Sca1(+)Lineage(-) cells, with insulin regulatory subunit-1 acting as a target of miR-126. Importantly, in EBF1-deficient hematopoietic progenitor cells, which fail to differentiate into B cells, miR-126 significantly up-regulated B220, and induced the expression of B-cell genes, including recombination activating genes-1/2 and CD79a/b. These data suggest that miR-126 can at least partly rescue B-cell development independently of EBF1. These experiments show that miR-126 regulates myeloid vs. B-cell fate through an alternative machinery, establishing the critical role of miRNAs in the lineage specification of multipotent mammalian cells.

Comparable long-term outcome of unrelated cord blood transplantation with related bone marrow or peripheral blood stem cell transplantation in patients aged 45 years or older with hematologic malignancies after myeloablative conditioning.

We investigated whether bone marrow or peripheral blood stem cells from older sibling donors or cord blood from unrelated donors provided a better outcome in allogeneic hematopoietic stem cell transplantation for relatively older patients who were candidates for myeloablative conditioning. Clinical outcomes of 97 patients aged 45 years or older with hematologic malignancies who received unrelated cord blood transplantation (CBT) (n = 66) or bone marrow transplantation (BMT) or peripheral blood stem cell transplantation (PBSCT) from related donors (n = 31) were compared. The cumulative incidences of grades III to IV acute and extensive chronic graft-versus-host diseases were similar between both groups. Although transplant-related mortality was significantly lower after CBT compared with BMT/PBSCT from related donors (hazard ratio [HR], .29, P = .04), overall mortality (HR, .72, P = .47) and relapse (HR, 2.02, P = .23) were not significantly different after CBT and BMT/PBSCT from related donors. These data suggest that CBT could be as safe and effective as BMT/PBSCT from older related donors for relatively older patients when it is used as a primary unrelated stem cell source.

Effect of ABO blood group incompatibility on the outcome of single-unit cord blood transplantation after myeloablative conditioning.

ABO blood group incompatibility between donor and recipient has been associated with poor transplant outcomes in allogeneic hematopoietic stem cell transplantation. However, its effect on the outcome of cord blood transplantation (CBT) has yet to be clarified. We retrospectively analyzed 191 adult patients who received single-unit CBT after myeloablative conditioning for malignant disease in our institute. Major mismatch showed a significantly lower incidence of platelet engraftment compared with ABO match as a reference (hazard ratio, .57; P = .01). Nevertheless, there was no increase in graft-versus-host disease, transplant-related mortality, and overall mortality after ABO-incompatible CBT. These data suggested that donor-recipient ABO incompatibility does not have a significant impact on outcome after myeloablative CBT for hematological malignancies.

Single-unit cord blood transplantation after granulocyte colony-stimulating factor-combined myeloablative conditioning for myeloid malignancies not in remission.

High disease burden in myeloablative allogeneic hematopoietic stem cell transplantation is associated with adverse outcomes in patients with acute myelogenous leukemia (AML) and myelodysplastic syndrome (MDS). Quiescent leukemia stem cells could be induced to enter cell cycle by granulocyte colony-stimulating factor (G-CSF) administration and become more susceptible to chemotherapy. We report on the outcome of unrelated cord blood transplantation (CBT) using a conditioning regimen of 12 Gy total body irradiation, G-CSF-combined high-dose cytarabine, and cyclophosphamide in 61 adult patients with AML or advanced MDS not in remission. With a median follow-up of 97 months, the probability of overall survival and cumulative incidence of relapse at 7 years were 61.4% and 30.5%, respectively. In multivariate analysis, poor-risk cytogenetics and high lactate dehydrogenase values at CBT were independently associated with inferior survival. These data demonstrate that CBT after G-CSF-combined myeloablative conditioning is a promising curative option for patients with myeloid malignancies not in remission.

Imatinib mesylate directly impairs class switch recombination through down-regulation of AID: its potential efficacy as an AID suppressor.

Activation-induced cytidine deaminase (AID) is essential for class switch recombination and somatic hypermutation. Its deregulated expression acts as a genomic mutator that can contribute to the development of various malignancies. During treatment with imatinib mesylate (IM), patients with chronic myeloid leukemia often develop hypogammaglobulinemia, the mechanism of which has not yet been clarified. Here, we provide evidence that class switch recombination on B-cell activation is apparently inhibited by IM through down-regulation of AID. Furthermore, expression of E2A, a key transcription factor for AID induction, was markedly suppressed by IM. These results elucidate not only the underlying mechanism of IM-induced hypogammaglobulinemia but also its potential efficacy as an AID suppressor.

Flow cytometric profiles with CD7 and CADM1 in CD4+ T cells are promising indicator for prognosis of aggressive ATL.

Adult T-cell leukemia/lymphoma (ATL) is a poor prognosis hematological malignancy originating from human T-cell leukemia virus (HTLV)-1-infected CD4+ T cells. Flow cytometric plots of CADM1 and CD7 in CD4+ T cells are useful for separating HTLV-1-uninfected T cells and ATL cells. They are indicators of clonal evolution of HTLV-1 infected cells and disease progression of asymptomatic carriers or indolent ATL. However, the impacts of the plots on the clinical course or prognosis of ATL, especially in aggressive ATL, remain unclear. We focused on the N fraction (CD4+ CADM1+ CD7-) reflecting ATL cells and analyzed the flow cytometric profiles and clinical course of 497 samples from 92 HTLV-1-infected patients that were mainly aggressive ATL. The parameters based on N fractions showed significant correlations with known indicators of ATL disease status (sIL-2R, LDH, abnormal lymphocytes, etc.) and sensitively reflected the treatment response of aggressive ATL. The parameters based on N fractions significantly stratified the prognosis of aggressive ATL at four different time points: before treatment, after one course of chemotherapy, at the best response after chemotherapy, and before allo-HCT. Even after mogamulizumab administration, which shows potent effects for peripheral blood lesions, the N fraction was still a useful indicator for prognostic estimation. In summary, this report shows that CADM1 versus CD7 plots in CD4+ T cells are useful indicators of the clinical course and prognosis of aggressive ATL. Therefore, this CADM1 and CD7 profile is suggested to be a useful prognostic indicator consistently from HTLV-1 carriers to aggressive ATL.

Phase II study in children and adults under 40 years with newly diagnosed Langerhans cell histiocytosis: protocol for an LCH-19-MSMFB clinical trial in Japan.

INTRODUCTION: Although the prognosis of Langerhans cell histiocytosis (LCH) is excellent, the high recurrence rate and permanent consequences, such as central diabetes insipidus and LCH-associated neurodegenerative diseases, remain to be resolved. Based on previous reports that patients with high-risk multisystem LCH show elevated levels of inflammatory molecules, we hypothesised that dexamethasone would more effectively suppress LCH-associated inflammation, especially in the central nervous system (CNS). We further hypothesised that intrathecal chemotherapy would effectively reduce CNS complications. We administer zoledronate to patients with multifocal bone LCH based on an efficacy report from a small case series. METHODS AND ANALYSIS: This phase II study (labelled the LCH-19-MSMFB study) is designed to evaluate the significance of introducing dexamethasone and intrathecal chemotherapy for multisystem disease and zoledronate for multifocal bone disease in previously untreated, newly diagnosed children, adolescents (under 20 years) and adults under 40 years. The primary endpoint is the 3-year event-free survival rate by risk group of under 20 years and the 3-year event-free survival rate of 20 years and over. ETHICS AND DISSEMINATION: This study was approved by the Central Review Board of the National Hospital Organisation Nagoya Medical Centre (Nagoya, Japan) on 21 January 2022 and was registered in the Japan Registry of Clinical Trials (https://jrct.niph.go.jp/en-latest-detail/jRCTs041210027). Written informed consent will be obtained from all patients and/or their guardians. TRIAL REGISTRATION NUMBER: jRCTs041210027.

Casirivimab/Imdevimab for Active COVID-19 Pneumonia Which Persisted for Nine Months in a Patient with Follicular Lymphoma during Anti-CD20 Therapy.

Immunocompromised patients are more likely to develop severe COVID-19, and exhibit high mortality. It is also hypothesized that chronic infection in these patients can be a risk factor for developing new variants. We describe a patient with prolonged active infection of COVID-19 who became infected during treatment with an anti-CD20 antibody (obinutuzumab) for follicular lymphoma. This patient had persistent RT-PCR positivity and live virus isolation for nine months despite treatment with remdesivir and other potential antiviral therapies. The computed tomography image of the chest showed that the viral pneumonia repeatedly appeared and disappeared in different lobes, as if a new infection had occurred continuously. The patient's SARS-CoV-2 antibody titer was negative throughout the illness, even after two doses of the BNT162b2 mRNA vaccine were administered in the seventh month of infection. A combination of monoclonal antibody therapy against COVID-19 (casirivimab and imdevimab) and antivirals resulted in negative RT-PCR results, and the virus was no longer isolated. The patient was clinically cured. During the 9-month active infection period, no fixed mutations in the spike (S) protein were detected, and the in vitro susceptibility to remdesivir was retained. Therapeutic administration of anti-SARS-CoV-2 monoclonal antibodies is essential in immunocompromised patients. Therefore, measures to prevent resistance against these key drugs are urgently needed.