Dexamethasone is a key component of induction for newly diagnosed multiple myeloma (NDMM), despite common toxicities, including hyperglycemia and insomnia. In the randomized ECOG E4A03 trial, dexamethasone 40 mg once weekly was associated with lower mortality than higher doses. However, the performance of dexamethasone dose reductions below this threshold with regard to progression-free survival (PFS) and overall survival (OS) in NDMM has not been fully characterized. We conducted a secondary pooled analysis of the SWOG 0777 and SWOG 1211 studies of NDMM, which used lenalidomide and dexamethasone (Rd) alone, with or without bortezomib, and with or without elotuzumab. The planned dexamethasone intensity was 40 to 60 mg weekly in all arms. Patients were categorized into FD-DEX (full-dose dexamethasone maintained throughout induction) or LD-DEX (lowered-dose dexamethasone or discontinuation; only permitted for grade 3+ toxicities per both study protocols). Of the 541 evaluated patients, the LD-DEX group comprised 373 patients (69%). There were no differences in PFS or OS between the FD-DEX and LD-DEX groups, which were balanced in terms of age, stage, and performance status. Predictors of PFS and OS in the multivariate models were treatment arm, age ≥70 years, and thrombocytopenia. FD-DEX did not significantly improve either outcome. Our study suggests that dexamethasone dose reductions are common in multiple myeloma, even within clinical trials. Given the many toxicities and unclear benefits of dexamethasone in the era of modern treatment regimens, dexamethasone dose reduction during NDMM induction warrants further prospective studies. These trials were registered at www.clinicaltrials.gov as #NCT00644228 and NCT01668719.

Adoptive T-cell therapy is a promising therapy for multiple myeloma (MM), but its efficacy hinges on understanding the relevant biologic and predictive markers of response. B-cell maturation antigen (BCMA) is a key target antigen in MM with active development of multiple anti-BCMA T-cell engagers (TCEs) and chimeric antigen receptor T-cell therapies. The regulation of surface BCMA expression by MM cells, which leads to shedding of soluble BCMA (sBCMA), has triggered debate about the significance of sBCMA as a predictive marker and its potential impact on treatment outcomes. To address this, we leveraged whole-genome sequencing and in vitro assays to demonstrate that sBCMA may independently predict primary refractoriness to anti-BCMA therapies. In addition to sBCMA, tumor burden and surface BCMA antigen density collectively influenced the anti-BCMA TCE cytotoxic efficacy. Correlative analyses of 163 patients treated with the anti-BCMA TCE teclistamab validated and further underscored the association between elevated baseline sBCMA (>400 ng/mL) and refractoriness. Importantly, increasing the TCE dose, using TCE against alternative targets (eg, GPRC5D), and gamma secretase inhibitors were able to overcome the high sBCMA levels. These findings highlight the importance of taking into account the baseline sBCMA levels, disease burden, and TCE dose intensity when administering anti-BCMA TCEs, thereby offering critical insights for optimizing therapeutic strategies to overcome specific high-risk features and primary anti-BCMA TCE refractoriness.

A metronomic, low-dose schedule of decitabine and venetoclax was safe and effective in myeloid malignancies with few dose reductions or interruptions in an older diverse population. Median overall survival for patients with acute myeloid leukemia and a TP53-mutation was 16.1 and 11.3 months, respectively. This trial was registered at www.clinicaltrials.gov as #NCT05184842.

Telomere biology disorders (TBDs), caused by pathogenic germ line variants in telomere-related genes, present with multiorgan disease and a predisposition to cancer. Clonal hematopoiesis (CH) as a marker of cancer development and survival in TBDs is poorly understood. Here, we characterized the clonal landscape of a large cohort of 207 patients with TBD with a broad range of age and phenotype. CH occurred predominantly in symptomatic patients and in signature genes typically associated with cancers: PPM1D, POT1, TERT promoter (TERTp), U2AF1S34, and/or TP53. Chromosome 1q gain (Chr1q+) was the commonest karyotypic abnormality. Clinically, multiorgan involvement and CH in TERTp, TP53, and splicing factor genes were associated with poorer overall survival. Chr1q+ and splicing factor or TP53 mutations significantly increased the risk of hematologic malignancies, regardless of clonal burden. Chr1q+ and U2AF1S34 mutated clones were premalignant events associated with the secondary acquisition of mutations in genes related to hematologic malignancies. Similar to the known effects of Chr1q+ and TP53-CH, functional studies demonstrated that U2AF1S34 mutations primarily compensated for aberrant upregulation of TP53 and interferon pathways in telomere-dysfunctional hematopoietic stem cells, highlighting the TP53 pathway as a canonical route of malignancy in TBD. In contrast, somatic POT1/PPM1D/TERTp mutations had distinct trajectories unrelated to cancer development. With implications beyond TBD, our data show that telomere dysfunction is a strong selective pressure for CH. In TBD, CH is a poor prognostic marker associated with worse overall survival. The identification of key regulatory pathways that drive clonal transformation in TBD allows for the identification of patients at a higher risk of cancer development.

Venetoclax (VEN) received full approval in October 2020 for use in older patients who are unfit with acute myeloid leukemia (AML) combined with either hypomethylating agents or low-dose cytarabine. This ended a semicentennial of stalled clinical progress and initiated a new treatment option with proven capacity to enhance response and prolong survival in older patients with AML. Despite widespread use of azacitidine-VEN (AZA-VEN), there is increasing appreciation that this regimen is myelosuppressive and associated with a higher risk of infectious complications than AZA alone. Key principles of initial management include prevention of tumor lysis syndrome in patients at high risk and minimizing infectious complications during induction. In the postremission phase, limiting cumulative marrow suppression by allowing sufficient time between cycles for optimal marrow recovery and truncating the duration of VEN exposure for those with delayed blood count recovery have emerged as important axioms of effective care. This article casts a clinical spotlight on important challenges and dilemmas encountered in practice. We also outline a structured framework to assist in the safe management of AZA-VEN in the clinic.

Oncogenes can be activated in cis through multiple mechanisms including enhancer hijacking events and noncoding mutations that create enhancers or promoters de novo. These paradigms have helped parse somatic variation of noncoding cancer genomes, thereby providing a rationale to identify noncanonical mechanisms of gene activation. Here we describe a novel mechanism of oncogene activation whereby focal copy number loss of an intronic element within the FTO gene leads to aberrant expression of IRX3, an oncogene in T-cell acute lymphoblastic leukemia (T-ALL). Loss of this CTCF-bound element downstream to IRX3 (+224 kb) leads to enhancer hijack of an upstream developmentally active super-enhancer of the CRNDE long noncoding RNA (-644 kb). Unexpectedly, the CRNDE super-enhancer interacts with the IRX3 promoter with no transcriptional output until it is untethered from the FTO intronic site. We propose that "promoter tethering" of oncogenes to inert regions of the genome is a previously unappreciated biological mechanism preventing tumorigenesis.

At least 25% to 35% of patients with large B-cell lymphoma (LBCL) are not cured with frontline treatment, with generally poor subsequent outcomes. This motivates ongoing and intense interest in improving the frontline treatment of this disease. R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone) has remained the standard of care for 20 years despite dozens of trials aiming to improve upon this regimen, and only recently has a novel regimen (pola-R-CHP [polatuzumab vedotin, rituximab, cyclophosphamide, doxorubicin, and prednisone]) challenged its supremacy. Fortunately, at least 15 promising randomized trials evaluating new treatments in frontline LBCL treatment are underway. They differ not only in the therapy evaluated in the experimental arm, but in the choice of control arm, primary end point, and patient selection strategy, with some targeting specific biologic subtypes, some focusing on specific high-risk patient populations, and others enrolling older or frail patients. Novel response-adapted strategies leveraging circulating tumor DNA are also underway. Although this variety of approaches provides a welcome increase in the overall likelihood of success, it will also present challenges if several of these trials are successful and we must choose among multiple potential treatment options that were not all tested in the same fashion. In this review, we summarize the main ongoing frontline randomized trials and discuss some of the questions that we will face in interpreting and applying their results in clinical practice in the next few years.

Chimeric antigen receptor T-cell therapy (CAR-T) targeting CD19 has transformed the management of relapsed/refractory (R/R) B-cell acute lymphoblastic leukemia (B-ALL), with the US Food and Drug Administration approval of tisagenlecleucel for pediatric/young adult patients and brexucabtagene autoleucel for adults. Efficacy is contingent upon several factors including disease burden. Emerging data suggest that bridging therapy, lymphodepletion, and, for some patients, consolidation therapy have an important role in the success of treatment. Furthermore, strategies to define and manage immunotoxic side effects including hematotoxicity is critical to safe delivery. Advancements in CAR-T design beyond CD19 represent an ongoing therapeutic evolution. Overall, CAR-T signifies a paradigm shift in B-ALL management, with the potential for improved remission and survival in a historically challenging patient population.

The ALPINE trial established the superiority of zanubrutinib over ibrutinib in patients with relapsed/refractory chronic lymphocytic leukemia and small lymphocytic lymphoma; here, we present data from the final comparative analysis with extended follow-up. Overall, 652 patients received zanubrutinib (n = 327) or ibrutinib (n = 325). At an overall median follow-up of 42.5 months, progression-free survival benefit with zanubrutinib vs ibrutinib was sustained (hazard ratio [HR], 0.68; 95% confidence interval [CI], 0.54-0.84), including in patients with del(17p)/TP53 mutation (HR, 0.51; 95% CI, 0.33-0.78) and across multiple sensitivity analyses. Overall response rate remained higher with zanubrutinib compared with ibrutinib (85.6% vs 75.4%); responses deepened over time with complete response/complete response with incomplete bone marrow recovery rates of 11.6% (zanubrutinib) and 7.7% (ibrutinib). Although median overall survival has not been reached in either treatment group, fewer zanubrutinib patients have died than ibrutinib patients (HR, 0.77 [95% CI, 0.55-1.06]). With median exposure time of 41.2 and 37.8 months in zanubrutinib and ibrutinib arms, respectively, the most common nonhematologic adverse events included COVID-19-related infection (46.0% vs 33.3%), diarrhea (18.8% vs 25.6%), upper respiratory tract infection (29.3% vs 19.8%), and hypertension (27.2% vs 25.3%). Cardiac events were lower with zanubrutinib (25.9% vs 35.5%) despite similar rates of hypertension. Incidence of atrial fibrillation/flutter was lower with zanubrutinib vs ibrutinib (7.1% vs 17.0%); no cardiac deaths were reported with zanubrutinib vs 6 cardiac deaths with ibrutinib. This analysis, at 42.5 months median follow-up, demonstrates that zanubrutinib remains more efficacious than ibrutinib with an improved overall safety/tolerability profile. This trial was registered at www.ClinicalTrials.gov as #NCT03734016.

Children with ETV6::RUNX1 or high-hyperdiploid B-cell acute lymphoblastic leukemia (B-ALL) have favorable outcomes. The St. Jude (SJ) classification considers these patients low risk, regardless of their National Cancer Institute (NCI) risk classification, except when there is slow minimal residual disease (MRD) response or central nervous system/testicular involvement. We analyzed outcomes in children (aged 1-18.99 years) with these genotypes in the SJ Total XV/XVI studies (2000-2017). Patients with ETV6::RUNX1 (n = 222) or high-hyperdiploid (n = 296) B-ALL had 5-year event-free survival (EFS) of 97.7% ± 1.1% and 94.7% ± 1.4%, respectively. For ETV6::RUNX1, EFS was comparable between NCI standard-risk and high-risk patients and between SJ low-risk and standard-risk patients. Of the 40 NCI high-risk patients, 37 who received SJ low-risk therapy had excellent EFS (97.3% ± 2.8%). For high-hyperdiploid B-ALL, NCI high-risk patients had worse EFS than standard-risk patients (87.6% ± 4.5% vs 96.4% ± 1.3%; P = .016). EFS was similar for NCI standard-risk and high-risk patients classified as SJ low risk (96.0% ± 1.5% and 96.9% ± 3.2%; P = .719). However, EFS was worse for NCI high-risk patients than for NCI standard-risk patients receiving SJ standard/high-risk therapy (77.4% ± 8.2% vs 98.0% ± 2.2%; P = .004). NCI high-risk patients with ETV6::RUNX1 or high-hyperdiploid B-ALL who received SJ low-risk therapy had lower incidences of thrombosis (P = .013) and pancreatitis (P = .011) than those who received SJ standard/high-risk therapy. MRD-directed therapy yielded excellent outcomes, except for NCI high-risk high-hyperdiploid B-ALL patients with slow MRD response, who require new treatment approaches. Among NCI high-risk patients, 93% with ETV6::RUNX1 and 54% with high-hyperdiploid B-ALL experienced excellent outcomes with a low-intensity regimen. These trials were registered at www.clinicaltrials.gov as #NCT00137111 and #NCT00549848.

Juvenile xanthogranuloma (JXG) is a histiocytic neoplasm that usually presents in the skin. Rarely, extracutaneous localizations occur; the genetic drivers of this clinical variant of JXG remain incompletely characterized. We present detailed clinicopathologic and molecular data of 16 children with extracutaneous JXG and 5 adults with xanthogranulomas confined to the central nervous system (CNS) or soft tissue. Tissue samples were obtained through the Dutch Nationwide Pathology Databank and analyzed with an innovative sequencing technique capable of detecting both small genomic variants and gene rearrangements. Targetable kinase alterations were detected in 16 of 16 children and 1 of 5 adults. Alterations included CLTC::SYK fusions in 6 children and CSF1R mutations in 7 others; all below 2 years of age with soft tissue tumors. One child had a CSF1R mutation and MRC1::PDGFRB fusion. Most were treated surgically, although spontaneous regression occurred in 1 of 6 with CLTC::SYK and 2 of 7 with CSF1R mutations, underscoring that treatment is not always necessary. Tumors with CLTC::SYK fusions generally lacked Touton giant cells but exhibited many other histologic features of JXG and concordant methylation profiles. Using multispectral immunofluorescence, phosphorylated-spleen tyrosine kinase expression was localized to CD163+ histiocytes; tumors with CLTC::SYK fusions also demonstrated mTOR activation, cyclin D1 expression, and variable phosphorylated-extracellular signal-regulated kinase expression. BRAFV600E was detected in 1 child and 1 adult with CNS-xanthogranulomas; both responded to BRAF inhibition. Finally, a TPM3::NTRK1 fusion or MAP2K1 deletion was detected in 2 children with systemic JXG who experienced spontaneous disease regression. This study advances the molecular understanding of histiocytic neoplasms and may guide diagnostics and clinical management.

There are only a few options for patients with relapsed/refractory B-cell acute lymphoblastic leukemia (B-ALL), thus, this is a major area of unmet medical need. In this study, we reveal that the inclusion of a poison exon in RBM39, which could be induced by both CDK9 or CDK9 independent cyclin-dependent kinases, mitogen-activated protein kinases, glycogen synthase kinases, CDC-like kinases (CMGC) kinase inhibition, is recognized by the nonsense-mediated messenger RNA decay pathway for degradation. Targeting this poison exon in RBM39 with CMGC inhibitors led to protein downregulation and the inhibition of ALL growth, particularly in relapsed/refractory B-ALL. Mechanistically, disruption of cotranscriptional splicing by the inhibition of CMGC kinases, including DYRK1A, or inhibition of CDK9, which phosphorylate the C-terminal domain of RNA polymerase II (Pol II), led to alteration in the SF3B1 and Pol II association. Disruption of SF3B1 and the transcriptional elongation complex altered Pol II pausing, which promoted the inclusion of a poison exon in RBM39. Moreover, RBM39 ablation suppressed the growth of human B-ALL, and targeting RBM39 with sulfonamides, which degrade RBM39 protein, showed strong antitumor activity in preclinical models. Our data reveal that relapsed/refractory B-ALL is susceptible to pharmacologic and genetic inhibition of RBM39 and provide 2 potential strategies to target this axis.

Iron regulatory proteins (IRP1 and IRP2) play a pivotal role in maintaining cellular iron homeostasis by binding to iron-responsive elements (IREs) of target messenger RNAs and regulating the expression of these iron-related genes. Mice and humans who lack functional IRP1 develop erythrocytosis due to erythropoietin (EPO) overproduction, whereas those who lack IRP2 develop microcytic anemia, believed to result from iron deficiency of erythroblasts. Here, we discovered that IRP2 deficiency reduced the expression of hypoxia-inducible factor 2α (HIF2α) and its transcriptional target, EPO, thereby compromising the stress erythropoiesis response to generate red blood cells upon anemia. The distinct consequences of IRP2 and IRP1 on EPO result from the higher binding affinity of the HIF2α IRE for IRP1 than IRP2. This difference in binding affinity arises from a bulge uridine in the upper stem of HIF2α IRE that impairs the ability of IRP2 to bind the IRE. These results reveal that IRP1 and IRP2 play distinct roles in erythropoiesis and unveil an unsuspected IRE binding preference that contributes to the divergent phenotypes observed in IRP1- and IRP2-deficient mammals.

Pretransplant detection of KMT2Ar measurable residual disease ≥0.001% by quantitative polymerase chain reaction was associated with significantly inferior posttransplant survival (2-year relapse-free survival 17% vs 59%; P = .001) and increased 2-year cumulative incidence of relapse (75% vs 25%, P = .0004).