Genomic determinants of response and resistance to inotuzumab ozogamicin in B-cell ALL.

ABSTRACT: Inotuzumab ozogamicin (InO) is an antibody-drug conjugate that delivers calicheamicin to CD22-expressing cells. In a retrospective cohort of InO-treated patients with B-cell acute lymphoblastic leukemia, we sought to understand the genomic determinants of the response and resistance to InO. Pre- and post-InO-treated patient samples were analyzed by whole genome, exome, and/or transcriptome sequencing. Acquired CD22 mutations were observed in 11% (3/27) of post-InO-relapsed tumor samples, but not in refractory samples (0/16). There were multiple CD22 mutations per sample and the mechanisms of CD22 escape included epitope loss (protein truncation and destabilization) and epitope alteration. Two CD22 mutant cases were post-InO hyper-mutators resulting from error-prone DNA damage repair (nonhomologous/alternative end-joining repair, or mismatch repair deficiency), suggesting that hypermutation drove escape from CD22-directed therapy. CD22-mutant relapses occurred after InO and subsequent hematopoietic stem cell transplantation (HSCT), suggesting that InO eliminated the predominant clones, leaving subclones with acquired CD22 mutations that conferred resistance to InO and subsequently expanded. Acquired loss-of-function mutations in TP53, ATM, and CDKN2A were observed, consistent with a compromise of the G1/S DNA damage checkpoint as a mechanism for evading InO-induced apoptosis. Genome-wide CRISPR/Cas9 screening of cell lines identified DNTT (terminal deoxynucleotidyl transferase) loss as a marker of InO resistance. In conclusion, genetic alterations modulating CD22 expression and DNA damage response influence InO efficacy. Our findings highlight the importance of defining the basis of CD22 escape and eradication of residual disease before HSCT. The identified mechanisms of escape from CD22-targeted therapy extend beyond antigen loss and provide opportunities to improve therapeutic approaches and overcome resistance. These trials were registered at www.ClinicalTrials.gov as NCT01134575, NCT01371630, and NCT03441061.

Interrogating bromodomain inhibitor resistance in KMT2A-rearranged leukemia through combinatorial CRISPR screens.

Bromo- and extra-terminal domain inhibitors (BETi) have exhibited therapeutic activities in many cancers. However, the mechanisms controlling BETi response and resistance are not well understood. We conducted genome-wide loss-of-function CRISPR screens using BETi-treated KMT2A-rearranged (KMT2A-r) cell lines. We revealed that Speckle-type POZ protein (SPOP) gene (Speckle Type BTB/POZ Protein) deficiency caused significant BETi resistance, which was further validated in cell lines and xenograft models. Proteomics analysis and a kinase-vulnerability CRISPR screen indicated that cells treated with BETi are sensitive to GSK3 perturbation. Pharmaceutical inhibition of GSK3 reversed the BETi-resistance phenotype. Based on this observation, a combination therapy regimen inhibiting both BET and GSK3 was developed to impede KMT2A-r leukemia progression in patient-derived xenografts in vivo. Our results revealed molecular mechanisms underlying BETi resistance and a promising combination treatment regimen of ABBV-744 and CHIR-98014 by utilizing unique ex vivo and in vivo KMT2A-r PDX models.

Erythroid/megakaryocytic differentiation confers BCL-XL dependency and venetoclax resistance in acute myeloid leukemia.

Myeloid neoplasms with erythroid or megakaryocytic differentiation include pure erythroid leukemia, myelodysplastic syndrome with erythroid features, and acute megakaryoblastic leukemia (FAB M7) and are characterized by poor prognosis and limited treatment options. Here, we investigate the drug sensitivity landscape of these rare malignancies. We show that acute myeloid leukemia (AML) cells with erythroid or megakaryocytic differentiation depend on the antiapoptotic protein B-cell lymphoma (BCL)-XL, rather than BCL-2, using combined ex vivo drug sensitivity testing, genetic perturbation, and transcriptomic profiling. High-throughput screening of >500 compounds identified the BCL-XL-selective inhibitor A-1331852 and navitoclax as highly effective against erythroid/megakaryoblastic leukemia cell lines. In contrast, these AML subtypes were resistant to the BCL-2 inhibitor venetoclax, which is used clinically in the treatment of AML. Consistently, genome-scale CRISPR-Cas9 and RNAi screening data demonstrated the striking essentiality of BCL-XL-encoding BCL2L1 but not BCL2 or MCL1, for the survival of erythroid/megakaryoblastic leukemia cell lines. Single-cell and bulk transcriptomics of patient samples with erythroid and megakaryoblastic leukemias identified high BCL2L1 expression compared with other subtypes of AML and other hematological malignancies, where BCL2 and MCL1 were more prominent. BCL-XL inhibition effectively killed blasts in samples from patients with AML with erythroid or megakaryocytic differentiation ex vivo and reduced tumor burden in a mouse erythroleukemia xenograft model. Combining the BCL-XL inhibitor with the JAK inhibitor ruxolitinib showed synergistic and durable responses in cell lines. Our results suggest targeting BCL-XL as a potential therapy option in erythroid/megakaryoblastic leukemias and highlight an AML subgroup with potentially reduced sensitivity to venetoclax-based treatments.

Venetoclax and idasanutlin in relapsed/refractory AML: a nonrandomized, open-label phase 1b trial.

This phase 1b trial (NCT02670044) evaluated venetoclax-idasanutlin in patients with relapsed/refractory (R/R) acute myeloid leukemia (AML) ineligible for cytotoxic chemotherapy. Two-dimensional dose escalation (DE, n = 50) was performed for venetoclax daily with idasanutlin on days 1 to 5 in 28-day cycles, followed by dosing schedule optimization (n = 6) to evaluate reduced venetoclax schedules (21-/14-day dosing). Common adverse events (occurring in ≥40% of patients) included diarrhea (87.3% of patients), nausea (74.5%), vomiting (52.7%), hypokalemia (50.9%), and febrile neutropenia (45.5%). During DE, across all doses, composite complete remission (CRc; CR + CR with incomplete blood count recovery + CR with incomplete platelet count recovery) rate was 26.0% and morphologic leukemia-free state (MLFS) rate was 12%. For anticipated recommended phase 2 doses (venetoclax 600 mg + idasanutlin 150 mg; venetoclax 600 mg + idasanutlin 200 mg), the combined CRc rate was 34.3% and the MLFS rate was 14.3%. Pretreatment IDH1/2 and RUNX1 mutations were associated with higher CRc rates (50.0% and 45.0%, respectively). CRc rate in patients with TP53 mutations was 20.0%, with responses noted among those with co-occurring IDH and RUNX1 mutations. In 12 out of 36 evaluable patients, 25 emergent TP53 mutations were observed; 22 were present at baseline with low TP53 variant allele frequency (median 0.0095% [range, 0.0006-0.4]). Venetoclax-idasanutlin showed manageable safety and encouraging efficacy in unfit patients with R/R AML. IDH1/2 and RUNX1 mutations were associated with venetoclax-idasanutlin sensitivity, even in some patients with co-occurring TP53 mutations; most emergent TP53 clones were preexisting. Our findings will aid ongoing/future trials of BCL-2/MDM2 inhibitor combinations. This trial was registered at www.clinicaltrials.gov as #NCT02670044.

North American Blastic Plasmacytoid Dendritic Cell Neoplasm Consortium: position on standards of care and areas of need.

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare hematologic malignancy with historically poor outcomes and no worldwide consensus treatment approach. Unique among most hematologic malignancies for its frequent cutaneous involvement, BPDCN can also invade other extramedullary compartments, including the central nervous system. Generally affecting older adults, many patients are unfit to receive intensive chemotherapy, and although hematopoietic stem cell transplantation is preferred for younger, fit individuals, not all are eligible. One recent therapeutic breakthrough is that all BPDCNs express CD123 (IL3Rα) and that this accessible surface marker can be pharmacologically targeted. The first-in-class agent for BPDCN, tagraxofusp, which targets CD123, was approved in December 2018 in the United States for patients with BPDCN aged ≥2 years. Despite favorable response rates in the frontline setting, many patients still relapse in the setting of monotherapy, and outcomes in patients with relapsed/refractory BPDCN remain dismal. Therefore, novel approaches targeting both CD123 and other targets are actively being investigated. To begin to formally address the state of the field, we formed a new collaborative initiative, the North American BPDCN Consortium (NABC). This group of experts, which includes a multidisciplinary panel of hematologists/oncologists, hematopoietic stem cell transplant physicians, pathologists, dermatologists, and pediatric oncologists, was tasked with defining the current standard of care in the field and identifying the most important research questions and future directions in BPDCN. The position findings of the NABC's inaugural meetings are presented herein.

Pivekimab sunirine (IMGN632), a novel CD123-targeting antibody-drug conjugate, in relapsed or refractory acute myeloid leukaemia: a phase 1/2 study.

BACKGROUND: Pivekimab sunirine (IMGN632) is a first-in-class antibody-drug conjugate comprising a high-affinity CD123 antibody, cleavable linker, and novel indolinobenzodiazepine pseudodimer payload. CD123 is overexpressed in several haematological malignancies, including acute myeloid leukaemia. We present clinical data on pivekimab sunirine in relapsed or refractory acute myeloid leukaemia. METHODS: This first-in-human, phase 1/2 dose-escalation and dose-expansion study enrolled participants aged 18 years or older at nine hospitals in France, Italy, Spain, and the USA with CD123+ haematological malignancies (Eastern Cooperative Oncology Group performance status of 0-1); participants reported here were in a cohort of participants with acute myeloid leukaemia who were refractory to or had relapsed on one or more previous treatments for acute myeloid leukaemia. The 3 + 3 dose-escalation phase evaluated two dosing schedules: schedule A (once every 3 weeks, on day 1 of a 3-week cycle) and fractionated schedule B (days 1, 4, and 8 of a 3-week cycle). The dose-expansion phase evaluated two cohorts: one cohort given 0·045 mg/kg of bodyweight (schedule A) and one cohort given 0·090 mg/kg of bodyweight (schedule A). The primary endpoints were the maximum tolerated dose and the recommended phase 2 dose. Antileukaemia activity (overall response and a composite complete remission assessment) was a secondary endpoint. The study is ongoing and registered with ClinicalTrials.gov, NCT03386513. FINDINGS: Between Dec 29, 2017, and May 27, 2020, 91 participants were enrolled (schedule A, n=68; schedule B, n=23). 30 (44%) of schedule A participants were female and 38 (56%) were male; 60 (88%) were White, six (9%) were Black or African American, and two (3%) were other races. Pivekimab sunirine at doses of 0·015 mg/kg to 0·450 mg/kg in schedule A was administered in six escalating doses with no maximum tolerated dose defined; three dose-limiting toxicities were observed (reversible veno-occlusive disease; 0·180 mg/kg, n=1 and 0·450 mg/kg, n=1; and neutropenia; 0·300 mg/kg, n=1). Schedule B was not pursued further on the basis of comparative safety and antileukaemia findings with schedule A. The recommended phase 2 dose was selected as 0·045 mg/kg once every 3 weeks. At the recommended phase 2 dose (n=29), the most common grade 3 or worse treatment-related adverse events were febrile neutropenia (three [10%]), infusion-related reactions (two [7%]), and anaemia (two [7%]). Treatment-related serious adverse events occurring in 5% or more of participants treated at the recommended phase 2 dose were febrile neutropenia (two [7%]) and infusion-related reactions (two [7%]). Among 68 participants who received schedule A, one death (1%) was considered to be treatment-related (cause unknown; 0·300 mg/kg cohort). At the recommended phase 2 dose, the overall response rate was 21% (95% CI 8-40; six of 29) and the composite complete remission rate was 17% (95% CI 6-36; five of 29). INTERPRETATION: Pivekimab sunirine showed single-agent activity across multiple doses, with a recommended phase 2 dose of 0·045 mg/kg once every 3 weeks. These findings led to a phase 1b/2 study of pivekimab sunirine plus azacitidine and venetoclax in patients with CD123-positive acute myeloid leukaemia. FUNDING: ImmunoGen.

Tagraxofusp, a first-in-class CD123-targeted agent: Five-year postapproval comprehensive review of the literature.

Tagraxofusp is a first-in-class CD123-directed conjugate of an amended diphtheria toxin platform and recombinant interleukin 3. Binding and subsequent internalization of the drug result in cell death via disruption of intracellular protein synthesis. CD123 is a surface marker that is expressed in several hematological malignancies, especially blastic plasmacytoid dendritic cell neoplasm (BPDCN), where its expression is ubiquitous. A pivotal study of tagraxofusp in BPDCN resulted in its approval for the treatment of BPDCN, the first treatment approved for this indication. Since the introduction of tagraxofusp, research has focused on the management of adverse effects, combination therapy to improve outcomes in fit patients, and dosing and combination strategies to mitigate toxicities while preserving efficacy, especially among older patients. The successful targeting of CD123 in BPDCN has also encouraged research into a variety of other CD123-positive hematological neoplasms, including acute myeloid leukemia (AML), and informed the development of other novel agents targeting CD123. This review examines the clinical data leading to the development and approval of tagraxofusp in BPDCN, how it is being used in combination to improve outcomes in BPDCN and AML, and its developing role in other hematological malignancies.

Evidence supporting a role for the immune checkpoint protein B7-H3 in NK cell-mediated cytotoxicity against AML.

We observed that the immune checkpoint protein B7-H3 is overexpressed in acute myeloid leukemia (AML) patients with poor treatment outcomes. Inhibition of B7-H3 expression or blocking of its activity using a novel monoclonal antibody (T-1A5) in AML cells significantly enhanced natural killer (NK) cell-mediated cytotoxicity in AML cells in vitro and in vivo. Moreover, a human-mouse chimera of this antibody (ChT-1A5) induced antibody-dependent cell-mediated cytotoxicity (ADCC) in B7-H3+ primary AML cells, but not in normal hematopoietic cells, suggesting the specify of this antibody for AML cells. Epitope mapping studies identified that both T-1A5 and ChT-1A5 antibodies bind to the FG-loop region of B7-H3, which is known to regulate the immunosuppressive function of B7-H3. Furthermore, treatment with ChT-1A5 in combination with human NK cells significantly prolonged survival in AML patient-derived xenograft (PDX) models. Our results suggest that the ChT-1A5 antibody can inhibit the immunosuppressive function of B7-H3 protein as well as induce ADCC in B7-H3+ AML.

Socio-demographic determinants of myelofibrosis outcomes in an underserved center and the SEER national database.

The influence of demographic characteristics and social determinants on cancer outcomes is widely recognized in various malignancies but remains understudied in myelofibrosis (MF). This study aims to investigate social and demographic variables associated with MF survival. We retrospectively reviewed data of biopsy-proven MF patients from the Surveillance, Epidemiology and End Results (SEER) database (2000-2021) and Montefiore Medical Center (2000-2023), an underserved inner-city hospital. The SEER cohort included 5,403 MF patients and was predominantly Non-Hispanic (NH) White (82%) with a median age of 69 years. The age-adjusted incidence rate of MF was 0.32 cases per 100,000 person-years, increasing annually by 1.3% from 2000 to 2021. Two- and five- year overall survival rates were 69% and 42%, respectively. Worse cause-specific survival was associated with older age, male sex, and diagnosis before 2011 (year of Ruxolitinib approval). NH-Black ethnicity, unmarried status and lower median income were independent predictors of worse overall survival. The single-center analysis included 84 cases, with a median age of 66 years. NH-White patients comprised 37% of the sample, followed by NH-Black (28.5%). Two- and five- year overall survival rates were 90% and 61%, respectively, with NH-Black patients exhibiting the lowest median survival, although the difference was not statistically significant. Age was a significant predictor of worse survival in this cohort. NH-Black and Hispanic patients lived in areas with higher socioeconomic and demographic stress compared to NH-White patients. Overall, this study highlights the association of social and demographic factors with MF survival and emphasizes the need for equitable healthcare and further exploration of social-demographic factors affecting MF survival.

Diagnosing and Treating Blastic Plasmacytoid Dendritic Cell Neoplasm in a Resource-Limited Setting.

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare and aggressive hematological malignancy with limited treatment options and poor prognosis. This case report presents the clinical course and management of a 62-year-old man with BPDCN in a resource-limited setting. The patient presented with constitutional symptoms and abnormal complete blood count findings. Initial treatment was performed with an acute lymphoblastic leukemia-based chemotherapy regimen, and the patient achieved complete remission, but the disease recurred 7 months after the initial diagnosis was confirmed in April 2022. The subsequent therapy was not effective, and the patient died during treatment. This case highlights the challenges in managing BPDCN and the need for further research to improve outcomes.

Novel Therapeutic Targets in Acute Myeloid Leukemia (AML).

PURPOSE OF REVIEW: This review seeks to identify and describe novel genetic and protein targets and their associated therapeutics currently being used or studied in the treatment of acute myeloid leukemia (AML). RECENT FINDINGS: Over the course of the last 5-6 years, several targeted therapies have been approved by the FDA, for the treatment of both newly diagnosed as well as relapsed/refractory AML. These novel therapeutics, as well as several others currently under investigation, have demonstrated activity in AML and have improved outcomes for many patients. Patient outcomes in AML have slowly improved over time, though for many patients, particularly elderly patients or those with relapsed/refractory disease, mortality remains very high. With the identification of several molecular/genetic drivers and protein targets and development of therapeutics which leverage those mechanisms to target leukemic cells, outcomes for patients with AML have improved and continue to improve significantly.

Author Correction: Metabolic gatekeeper function of B-lymphoid transcription factors.

In Fig. 3c of this Letter, the the effects of CRISPR-Cas9-mediated deletion of NR3C1, TXNIP and CNR2 in patient-derived B-lineage leukaemia cells were shown. For curves depicting NR3C1 (left graph), data s for TXNIP (middle graph) were inadvertently plotted. This figure has been corrected online, and the original Fig. 3c is shown as Supplementary Information to this Amendment for transparency. The error does not affect the conclusions of the Letter. In addition, Source Data files have been added for the Figs. 1-4 and Extended Data Figs. 1-10 of the original Letter.

Triple combination targeting methyltransferase, BCL-2, and PD-1 facilitates antileukemia responses in acute myeloid leukemia.

BACKGROUND: A recent breakthrough therapy combining the BCL-2 inhibitor venetoclax with hypomethylating agents (HMAs) targeting DNA methyltransferase has improved outcomes for patients with acute myeloid leukemia (AML), but the responses and long-term survival in older/unfit patients and in patients with relapsed/refractory AML remain suboptimal. Recent studies showed that inhibition of BCL-2 or DNA methyltransferase modulates AML T-cell immunity. METHODS: By using flow cytometry and time-of-flight mass cytometry, the authors examined the effects of the HMA decitabine combined with the BCL-2 inhibitor venetoclax (DAC/VEN therapy) on leukemia cells and T cells in patients with AML who received DAC/VEN therapy in a clinical trial. The authors investigated the response of programmed cell death protein 1 (PD-1) inhibition in the DAC/VEN-treated samples in vitro and investigated the triple combination of PD-1 inhibition with HMA/venetoclax in the trial patients who had AML. RESULTS: DAC/VEN therapy effectively targeted leukemia cells and upregulated the expression of the immune checkpoint-inhibitory receptor PD-1 in T cells while preserving CD4-positive and CD8-positive memory T cells in a subset of patients with AML who were tested. In vitro PD-1 inhibition potentiated the antileukemia response in DAC/VEN-treated AML samples. The combined use of azacitidine, venetoclax, and nivolumab eliminated circulating blasts and leukemia stem cells/progenitor cells and expanded the percentage of CD8-positive memory T cells in an illustrative patient with relapsed AML who responded to the regimen in an ongoing clinical trial. CONCLUSIONS: Immunomodulation by targeting PD-1 enhances the therapeutic effect of combining an HMA and venetoclax in patients with AML.

A retrospective study of cladribine and low-dose cytarabine-based regimens for the treatment of chronic myelomonocytic leukemia and secondary acute myeloid leukemia.

BACKGROUND: Patients with higher risk chronic myelomonocytic leukemia (CMML) have limited therapeutic options beyond hydroxyurea and hypomethylating agents (HMAs). Regimens based on a backbone of cladribine (CLAD), low-dose cytarabine (LDAC), and an HMA are effective low-intensity therapies for acute myeloid leukemia (AML). METHODS: The authors conducted a retrospective chart review to evaluate the efficacy of CLAD/LDAC/HMA in CMML and secondary acute myeloid leukemia (sAML) arising from CMML. Responses were evaluated according to the 2006 International Working Group criteria for CMML and the 2017 European LeukemiaNet criteria for AML. The overall survival (OS), leukemia-free survival (LFS), and duration of response were evaluated with the Kaplan-Meier method. Patients were stratified on the basis of prior HMA exposure. RESULTS: The authors identified 21 patients with CMML (eight with HMA-naive CMML and 13 with HMA-failure CMML) and 33 patients with sAML (11 with HMA-naive sAML and 22 with HMA-failure sAML) treated with CLAD/LDAC/HMA-based regimens. The CMML cohort was enriched for high-risk features (proliferative type, elevated blasts, and RAS/MAPK mutations). The overall response rate was 33% in CMML (50% in HMA-naive CMML and 23% in HMA-failure CMML) and 48% in sAML (82% in HMA-naive sAML and 32% in HMA-failure sAML). The median OS was 14.4, 8.8, 42.9, and 2.9 months for HMA-naive CMML, HMA-failure CMML, HMA-naive sAML, and HMA-failure sAML, respectively. The median LFS was 14.4 and 3.9 months for HMA-naive CMML and HMA-failure CMML, respectively. CONCLUSIONS: CLAD/LDAC/HMA-based regimens are effective in a subset of patients with higher risk CMML and sAML arising from CMML who have not previously experienced HMA failure. These findings must be confirmed in prospective studies.

Early mortality in acute myeloid leukemia with KMT2A rearrangement is associated with high risk of bleeding and disseminated intravascular coagulation.

BACKGROUND: Acute myeloid leukemia (AML) with rearrangement of lysine methyltransferase 2a gene (KMT2Ar) is characterized by chemotherapy resistance and high rates of relapse. However, additional causes of treatment failure or early mortality have not been well-defined in this entity. METHODS: In a retrospective analysis, causes and rates of early mortality following induction treatment were compared between a cohort of adults with KMT2Ar AML (N = 172) and an age-matched cohort of patients with normal karyotype AML (N = 522). RESULTS: The 60-day mortality in patients with KMT2Ar AML was 15% compared with 7% with normal karyotype (p = .04). We found a significantly higher occurrence of major bleeding events (p = .005) and total bleeding events (p = .001) in KMT2Ar AML compared with diploid AML. Among evaluable patients with KMT2Ar AML, 93% exhibited overt disseminated intravascular coagulopathy compared with 54% of patients with a normal karyotype before death (p = .03). In a multivariate analysis, KMT2Ar and a monocytic phenotypic were the only independent predictors of any bleeding event in patients who died within 60 days (odds ratio, 3.5; 95% CI, 1.4-10.4; p = .03; odds ratio, 3.2; 95% CI, 1-1-9.4; p = .04, respectively). CONCLUSION: In conclusion, early recognition and aggressive management of disseminated intravascular coagulopathy and coagulopathy are important considerations that could mitigate the risk of death during induction treatment in KMT2Ar AML. PLAIN LANGUAGE SUMMARY: Acute myeloid leukemia (AML) with rearrangement of KMT2A is characterized by chemotherapy resistance and high rates of relapse. However, additional causes of treatment failure or early mortality have not been well-defined in this entity. In this article, that KMT2A-rearranged AML is demonstrably associated with higher early mortality and an increased risk of bleeding and coagulopathy, specifically, disseminated intravascular coagulation, compared with normal karyotype AML. These findings emphasize the importance of monitoring and mitigating coagulopathy in KMT2A-rearranged leukemia similar to what is done in acute promyelocytic leukemia.

Azacitidine and Venetoclax in Previously Untreated Acute Myeloid Leukemia.

BACKGROUND: Older patients with acute myeloid leukemia (AML) have a dismal prognosis, even after treatment with a hypomethylating agent. Azacitidine added to venetoclax had promising efficacy in a previous phase 1b study. METHODS: We randomly assigned previously untreated patients with confirmed AML who were ineligible for standard induction therapy because of coexisting conditions, because they were 75 years of age or older, or both to azacitidine plus either venetoclax or placebo. All patients received a standard dose of azacitidine (75 mg per square meter of body-surface area subcutaneously or intravenously on days 1 through 7 every 28-day cycle); venetoclax (target dose, 400 mg) or matching placebo was administered orally, once daily, in 28-day cycles. The primary end point was overall survival. RESULTS: The intention-to-treat population included 431 patients (286 in the azacitidine-venetoclax group and 145 in the azacitidine-placebo [control] group). The median age was 76 years in both groups (range, 49 to 91). At a median follow-up of 20.5 months, the median overall survival was 14.7 months in the azacitidine-venetoclax group and 9.6 months in the control group (hazard ratio for death, 0.66; 95% confidence interval, 0.52 to 0.85; P<0.001). The incidence of complete remission was higher with azacitidine-venetoclax than with the control regimen (36.7% vs. 17.9%; P<0.001), as was the composite complete remission (complete remission or complete remission with incomplete hematologic recovery) (66.4% vs. 28.3%; P<0.001). Key adverse events included nausea of any grade (in 44% of the patients in the azacitidine-venetoclax group and 35% of those in the control group) and grade 3 or higher thrombocytopenia (in 45% and 38%, respectively), neutropenia (in 42% and 28%), and febrile neutropenia (in 42% and 19%). Infections of any grade occurred in 85% of the patients in the azacitidine-venetoclax group and 67% of those in the control group, and serious adverse events occurred in 83% and 73%, respectively. CONCLUSIONS: In previously untreated patients who were ineligible for intensive chemotherapy, overall survival was longer and the incidence of remission was higher among patients who received azacitidine plus venetoclax than among those who received azacitidine alone. The incidence of febrile neutropenia was higher in the venetoclax-azacitidine group than in the control group. (Funded by AbbVie and Genentech; VIALE-A ClinicalTrials.gov number, NCT02993523.).

DYRK1a mediates BAFF-induced noncanonical NF-κB activation to promote autoimmunity and B-cell leukemogenesis.

B-cell-activating factor (BAFF) mediates B-cell survival and, when deregulated, contributes to autoimmune diseases and B-cell malignancies. The mechanism connecting BAFF receptor (BAFFR) signal to downstream pathways and pathophysiological functions is not well understood. Here we identified DYRK1a as a kinase that responds to BAFF stimulation and mediates BAFF-induced B-cell survival. B-cell-specific DYRK1a deficiency causes peripheral B-cell reduction and ameliorates autoimmunity in a mouse model of lupus. An unbiased screen identified DYRK1a as a protein that interacts with TRAF3, a ubiquitin ligase component mediating degradation of the noncanonical nuclear factor (NF)-κB-inducing kinase (NIK). DYRK1a phosphorylates TRAF3 at serine-29 to interfere with its function in mediating NIK degradation, thereby facilitating BAFF-induced NIK accumulation and noncanonical NF-κB activation. Interestingly, B-cell acute lymphoblastic leukemia (B-ALL) cells express high levels of BAFFR and respond to BAFF for noncanonical NF-κB activation and survival in a DYRK1a-dependent manner. Furthermore, DYRK1a promotes a mouse model of B-ALL through activation of the noncanonical NF-κB pathway. These results establish DYRK1a as a critical BAFFR signaling mediator and provide novel insight into B-ALL pathogenesis.

Venetoclax enhances T cell-mediated antileukemic activity by increasing ROS production.

Venetoclax, a Bcl-2 inhibitor, in combination with the hypomethylating agent azacytidine, achieves complete remission with or without count recovery in ∼70% of treatment-naive elderly patients unfit for conventional intensive chemotherapy. However, the mechanism of action of this drug combination is not fully understood. We discovered that venetoclax directly activated T cells to increase their cytotoxicity against acute myeloid leukemia (AML) in vitro and in vivo. Venetoclax enhanced T-cell effector function by increasing reactive oxygen species generation through inhibition of respiratory chain supercomplexes formation. In addition, azacytidine induced a viral mimicry response in AML cells by activating the STING/cGAS pathway, thereby rendering the AML cells more susceptible to T cell-mediated cytotoxicity. Similar findings were seen in patients treated with venetoclax, as this treatment increased reactive oxygen species generation and activated T cells. Collectively, this study presents a new immune-mediated mechanism of action for venetoclax and azacytidine in the treatment of AML and highlights a potential combination of venetoclax and adoptive cell therapy for patients with AML.

Clonal dynamics and clinical implications of postremission clonal hematopoiesis in acute myeloid leukemia.

Although clonal hematopoiesis (CH) can precede the development of acute myeloid leukemia (AML), it can also persist after achieving remission. Long-term clonal dynamics and clinical implications of persistent CH are not well understood. Here, we studied the prevalence, dynamics, and clinical implications of postremission CH in 164 AML patients who attained complete remission after induction chemotherapies. Postremission CH was identified in 79 (48%) patients. Postremission CH persisted long term in 91% of the trackable patients despite treatment with various types of consolidation and maintenance therapies. Postremission CH was eradicated in 20 out of 21 (95%) patients who underwent allogeneic stem cell transplant. Although patients with postremission CH as a group had comparable hematopoiesis with those without it, patients with persistent TET2 mutations showed significant neutropenia long term. Postremission CH had little impact on relapse risk, nonrelapse mortality, and incidence of atherosclerotic cardiovascular disease, although the clinical impact of post-CR CH was heterogeneous among different mutations. These data suggest that although residual clonal hematopoietic stem cells are generally resistant to consolidation and maintenance therapies, they retain the ability to maintain normal hematopoiesis and have little impact on clinical outcomes. Larger study is needed to dissect the gene-specific heterogeneity.

2021 Update on MRD in acute myeloid leukemia: a consensus document from the European LeukemiaNet MRD Working Party.

Measurable residual disease (MRD) is an important biomarker in acute myeloid leukemia (AML) that is used for prognostic, predictive, monitoring, and efficacy-response assessments. The European LeukemiaNet (ELN) MRD Working Party evaluated standardization and harmonization of MRD in an ongoing manner and has updated the 2018 ELN MRD recommendations based on significant developments in the field. New and revised recommendations were established during in-person and online meetings, and a 2-stage Delphi poll was conducted to optimize consensus. All recommendations are graded by levels of evidence and agreement. Major changes include technical specifications for next-generation sequencing-based MRD testing and integrative assessments of MRD irrespective of technology. Other topics include use of MRD as a prognostic and surrogate end point for drug testing; selection of the technique, material, and appropriate time points for MRD assessment; and clinical implications of MRD assessment. In addition to technical recommendations for flow- and molecular-MRD analysis, we provide MRD thresholds and define MRD response, and detail how MRD results should be reported and combined if several techniques are used. MRD assessment in AML is complex and clinically relevant, and standardized approaches to application, interpretation, technical conduct, and reporting are of critical importance.