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Graft-versus-host disease (GVHD) is a major complication after allogeneic hematopoietic cell transplantation (allo-HCT). The hypomethylating agent azacitidine (AZA) has been shown to be effective in preclinical and clinical studies for the prevention of acute GVHD (aGVHD). We sought to determine the maximum tolerated dose (MTD) of AZA when given on days 1 to 5 of a 28-day cycle for 4 cycles, starting on day +7 after allo-HCT, as well as its impact on aGVHD and chronic GVHD (cGVHD), relapse, and overall survival (OS) in patients undergoing matched unrelated donor allo-HCT. This study was a single-arm, single-center, open-label phase I-II study with a total of 15 and 38 patients enrolled in the phase I and II portions of the trial, respectively. A standard 3+3 study design was used in phase I, and all patients in phase II received AZA at the MTD determined in phase I. The MTD of AZA starting at day +7 post-transplantation was 45 mg/m 2 . Phase II of the study was halted after enrolling 38 of the planned 46 patients following an interim analysis that suggested futility. Overall, AZA at 45 mg/m 2 exhibited a side effect profile consistent with prior reports and had a minimal impact on engraftment. The cumulative incidence of clinically significant aGVHD by day +180 was 39.9% (95% confidence interval [CI], 22% to 53.7%). The incidence of all-grade cGVHD was 61.4% (95% CI, 40.3% to 75%). At 1 year, OS was 73.7% (95% CI, 60.9% to 89.1%), and the disease relapse rate was 11.4% (95% CI, .2% to 21.3%). Our results suggest that early post-allo-HCT AZA has limited efficacy in preventing aGVHD and cGVHD but could have a beneficial effect in preventing disease relapse., (Copyright © 2023 The American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc. All rights reserved.)

Purpose: Persistent molecular disease (PMD) after induction chemotherapy predicts relapse in AML. In this study, we used whole-exome sequencing (WES) and targeted error-corrected sequencing to assess the frequency and mutational patterns of PMD in 30 patients with AML., Materials and Methods: The study cohort included 30 patients with adult AML younger than 65 years who were uniformly treated with standard induction chemotherapy. Tumor/normal WES was performed for all patients at presentation. PMD analysis was evaluated in bone marrow samples obtained during clinicopathologic remission using repeat WES and analysis of patient-specific mutations and error-corrected sequencing of 40 recurrently mutated AML genes (MyeloSeq)., Results: WES for patient-specific mutations detected PMD in 63% of patients (19/30) using a minimum variant allele fraction (VAF) of 2.5%. In comparison, MyeloSeq identified persistent mutations above 0.1% VAF in 77% of patients (23/30). PMD was usually present at relatively high levels (>2.5% VAFs), such that WES and MyeloSeq agreed for 73% of patients despite differences in detection limits. Mutations in DNMT3A , ASXL1 , and TET2 (ie, DTA mutations) were persistent in 16 of 17 patients, but WES also detected non-DTA mutations in 14 of these patients, which for some patients distinguished residual AML cells from clonal hematopoiesis. Surprisingly, MyeloSeq detected additional variants not identified at presentation in 73% of patients that were consistent with new clonal cell populations after chemotherapy., Conclusion: PMD and clonal hematopoiesis are both common in patients with AML in first remission. These findings demonstrate the importance of baseline testing for accurate interpretation of mutation-based tumor monitoring assays for patients with AML and highlight the need for clinical trials to determine whether these complex mutation patterns correlate with clinical outcomes in AML.

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., (© 2023 by The American Society of Hematology.)

Progression from myelodysplastic syndromes (MDS) to secondary acute myeloid leukemia (AML) is associated with the acquisition and expansion of subclones. Our understanding of subclone evolution during progression, including the frequency and preferred order of gene mutation acquisition, remains incomplete. Sequencing of 43 paired MDS and secondary AML samples identified at least one signaling gene mutation in 44% of MDS and 60% of secondary AML samples, often below the level of standard sequencing detection. In addition, 19% of MDS and 47% of secondary AML patients harbored more than one signaling gene mutation, almost always in separate, coexisting subclones. Signaling gene mutations demonstrated diverse patterns of clonal evolution during disease progression, including acquisition, expansion, persistence, and loss of mutations, with multiple patterns often coexisting in the same patient. Multivariate analysis revealed that MDS patients who had a signaling gene mutation had a higher risk of AML progression, potentially providing a biomarker for progression., Significance: Subclone expansion is a hallmark of progression from MDS to secondary AML. Subclonal signaling gene mutations are common at MDS (often at low levels), show complex and convergent patterns of clonal evolution, and are associated with future progression to secondary AML. See related article by Guess et al., p. 316 (33). See related commentary by Romine and van Galen, p. 270. This article is highlighted in the In This Issue feature, p. 265., (©2022 American Association for Cancer Research.)

Natural killer (NK) cells are a promising alternative to T cells for cancer immunotherapy. Adoptive therapies with allogeneic, cytokine-activated NK cells are being investigated in clinical trials. However, the optimal cytokine support after adoptive transfer to promote NK cell expansion, and persistence remains unclear. Correlative studies from 2 independent clinical trial cohorts treated with major histocompatibility complex-haploidentical NK cell therapy for relapsed/refractory acute myeloid leukemia revealed that cytokine support by systemic interleukin-15 (IL-15; N-803) resulted in reduced clinical activity, compared with IL-2. We hypothesized that the mechanism responsible was IL-15/N-803 promoting recipient CD8 T-cell activation that in turn accelerated donor NK cell rejection. This idea was supported by increased proliferating CD8+ T-cell numbers in patients treated with IL-15/N-803, compared with IL-2. Moreover, mixed lymphocyte reactions showed that IL-15/N-803 enhanced responder CD8 T-cell activation and proliferation, compared with IL-2 alone. Additionally, IL-15/N-803 accelerated the ability of responding T cells to kill stimulator-derived memory-like NK cells, demonstrating that additional IL-15 can hasten donor NK cell elimination. Thus, systemic IL-15 used to support allogeneic cell therapy may paradoxically limit their therapeutic window of opportunity and clinical activity. This study indicates that stimulating patient CD8 T-cell allo-rejection responses may critically limit allogeneic cellular therapy supported with IL-15. This trial was registered at www.clinicaltrials.gov as #NCT03050216 and #NCT01898793., (© 2022 by The American Society of Hematology.)

Leukemia stem cells utilize cell adhesion molecules like CXCR4/CXCL12 to home to bone marrow stromal niches where they are maintained in a dormant, protected state. Dociparstat sodium (DSTAT, CX-01) is a low anticoagulant heparin with multiple mechanisms of action, including inhibition of the CXCR4/CXCL12 axis, blocking HMGB1, and binding platelet factor 4 (PF-4). We conducted a pilot study adding DSTAT to azacitidine for patients with AML or MDS unresponsive to or relapsed after prior hypomethylating agent therapy, hypothesizing that DSTAT may improve response rates. Twenty patients were enrolled, with a median of 2 prior lines of therapy and 6 cycles of prior hypomethylating agents. Among fifteen patients evaluable for response, there was 1 complete remission, and 3 marrow complete remissions, for a response rate of 27 % among evaluable patients (20 % overall). Hematologic improvement was observed in 5 additional patients. The median overall survival for all enrolled patients was 205 days (95 % CI 119-302). While cytopenias and infections were common, these were not out of proportion to what would be expected in this population of patients undergoing treatment with azacitidine alone. In summary, this trial demonstrated the feasibility of combining DSTAT with azacitidine, with several responses observed, suggesting this combination warrants further study., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

The hypomethylating agent azacitidine can prolong overall survival (OS) in patients with higher risk-myelodysplastic syndromes (HR-MDS) compared to conventional regimens. However, outcomes differ largely between studies, making it challenging to determine the contribution of novel therapies added to azacitidine. Further, a discrepancy is seen between complete (CR) or partial (PR) response rates and OS improvement with azacitidine, making it challenging to rely on earlier endpoints than OS. We conducted a systematic literature search and study-level systematic review of 237 clinical studies to better understand outcomes for HR-MDS patients treated with azacitidine. Pooled marrow CR was 9% (N = 2654; 95% CI: 6-13 %), CR rate was 17 % (N = 6943; 95% CI: 15-20 %), and median OS (mOS) was 18.6 months (N = 2820; 95% CI: 15.3-21.9). A weak correlation to mOS was detected with CR rate (207 patient cohorts, Pearson's r = 0.315; P < 0.0005), and a much stronger correlation with median progression-free survival (mPFS) (r=0.88, P = 3 × 10 -14 ). Six-months progression-free survival rates correlated with 1-year OS rates but were only infrequently reported (N = 41 patient cohorts) therefore not allowing a robust recommendation for a surrogate to the established OS endpoint. Larger patient numbers and patient-level data appear necessary, especially for designing future clinical trials using azacitidine combinations., (Copyright © 2021 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Genomic analysis is essential for risk stratification in patients with acute myeloid leukemia (AML) or myelodysplastic syndromes (MDS). Whole-genome sequencing is a potential replacement for conventional cytogenetic and sequencing approaches, but its accuracy, feasibility, and clinical utility have not been demonstrated., Methods: We used a streamlined whole-genome sequencing approach to obtain genomic profiles for 263 patients with myeloid cancers, including 235 patients who had undergone successful cytogenetic analysis. We adapted sample preparation, sequencing, and analysis to detect mutations for risk stratification using existing European Leukemia Network (ELN) guidelines and to minimize turnaround time. We analyzed the performance of whole-genome sequencing by comparing our results with findings from cytogenetic analysis and targeted sequencing., Results: Whole-genome sequencing detected all 40 recurrent translocations and 91 copy-number alterations that had been identified by cytogenetic analysis. In addition, we identified new clinically reportable genomic events in 40 of 235 patients (17.0%). Prospective sequencing of samples obtained from 117 consecutive patients was performed in a median of 5 days and provided new genetic information in 29 patients (24.8%), which changed the risk category for 19 patients (16.2%). Standard AML risk groups, as defined by sequencing results instead of cytogenetic analysis, correlated with clinical outcomes. Whole-genome sequencing was also used to stratify patients who had inconclusive results by cytogenetic analysis into risk groups in which clinical outcomes were measurably different., Conclusions: In our study, we found that whole-genome sequencing provided rapid and accurate genomic profiling in patients with AML or MDS. Such sequencing also provided a greater diagnostic yield than conventional cytogenetic analysis and more efficient risk stratification on the basis of standard risk categories. (Funded by the Siteman Cancer Research Fund and others.)., (Copyright © 2021 Massachusetts Medical Society.)

Purpose: Physicians treating hematologic malignancies increasingly order targeted sequencing panels to interrogate recurrently mutated genes. The precise impact of these panels on clinical decision making is not well understood., Methods: Here, we report our institutional experience with a targeted 40-gene panel (MyeloSeq) that is used to generate a report for both genetic variants and variant allele frequencies for the treating physician (the limit of mutation detection is approximately one AML cell in 50)., Results: In total, 346 sequencing reports were generated for 325 patients with suspected hematologic malignancies over an 8-month period (August 2018 to April 2019). To determine the influence of genomic data on clinical care for patients with acute myeloid leukemia (AML), we analyzed 122 consecutive reports from 109 patients diagnosed with AML and surveyed the treating physicians with a standardized questionnaire. The panel was ordered most commonly at diagnosis (61.5%), but was also used to assess response to therapy (22.9%) and to detect suspected relapse (15.6%). The panel was ordered at multiple timepoints during the disease course for 11% of patients. Physicians self-reported that 50 of 114 sequencing reports (44%) influenced clinical care decisions in 44 individual patients. Influences were often nuanced and extended beyond identifying actionable genetic variants with US Food and Drug Administration-approved drugs., Conclusion: This study provides insights into how physicians are currently using multigene panels capable of detecting relatively rare AML cells. The most influential way to integrate these tools into clinical practice will be to perform prospective clinical trials that assess patient outcomes in response to genomically driven interventions., Competing Interests: The following represents disclosure information provided by authors of this manuscript. All relationships are considered compensated unless otherwise noted. Relationships are self-held unless noted. I = Immediate Family Member, Inst = My Institution. Relationships may not relate to the subject matter of this manuscript. For more information about ASCO's conflict of interest policy, please refer to www.asco.org/rwc or ascopubs.org/po/author-center. Open Payments is a public database containing information reported by companies about payments made to US-licensed physicians (Open Payments). Erica K. BarnellEmployment: Geneoscopy Stock and Other Ownership Interests: Geneoscopy Patents, Royalties, Other Intellectual Property: Inventor of intellectual property in start-up company (Geneoscopy) Travel, Accommodations, Expenses: GeneoscopyKenneth F. NewcomerEmployment: Geneoscopy (I) Stock and Other Ownership Interests: Geneoscopy (I) Patents, Royalties, Other Intellectual Property: Inventor of intellectual property owned by Geneoscopy (I)Zachary L. SkidmoreStock and Other Ownership Interests: Aim Immunotech, Catalyst PharmaceuticalsKilannin KrysiakConsulting or Advisory Role: Gerson Lehrman GroupLukas D. WartmanConsulting or Advisory Role: Novartis, IncyteStephen T. OhConsulting or Advisory Role: Incyte, Novartis, Blueprint Medicines, Celgene, Kartos, CTI BioPharma Corp, PharmaEssentia, Disc Medicine, Constellation Pharmaceuticals Research Funding: Incyte (Inst), Gilead Sciences (Inst), CTI BioPharma Corp (Inst), Kartos (Inst), Celgene (Inst), Sierra Oncology (Inst), Blueprint Medicines (Inst), Constellation Pharmaceuticals (Inst)John S. WelchConsulting or Advisory Role: Archer Biosciences, Agios Research Funding: Janssen Oncology (Inst), Notable Labs (Inst)Keith E. Stockerl-GoldsteinStock and Other Ownership Interests: Abbott Laboratories, AbbVie Consulting or Advisory Role: Celgene Research Funding: GlaxoSmithKline, Takeda, BiolineRx, Janssen Other Relationship: CellerantRavi VijConsulting or Advisory Role: Bristol Myers Squibb, Celgene, Janssen, Sanofi, Karyopharm Therapeutics, Takeda, Genentech, AbbVie, Oncopeptides Research Funding: Takeda, Celgene, Bristol Myers Squibb Travel, Accommodations, Expenses: Celgene, Bristol Myers Squibb, Sanofi, Janssen, DAVAOncology, Karyopharm Therapeutics, Amgen, Takeda, AbbVieAmanda F. CashenConsulting or Advisory Role: Agios Speakers' Bureau: Novartis, CelgeneIskra PusicConsulting or Advisory Role: Kadmon, Incyte, SyndaxCamille N. AbboudStock and Other Ownership Interests: AbbVie (I), Abbott Laboratories (I), Gilead Sciences (I), Bristol Myers Squibb (I), Johnson & Johnson (I) Honoraria: Cardinal Health, Dova Pharmaceuticals, NkartaTherapeutics, Archer Biosciences Research Funding: Actinium Pharmaceuticals, Selvita (Inst), AlloVir (Inst), Forty-Seven (Inst)Armin GhobadiHonoraria: Kite Pharma Consulting or Advisory Role: Kite Pharma, Celgene, Amgen, Wugen Speakers' Bureau: Kite Pharma, AmgenGeoffrey L. UyConsulting or Advisory Role: Astellas Pharma, Genentech, Jazz PharmaceuticalsMark A. SchroederConsulting or Advisory Role: Astellas Pharma, Dova Pharmaceuticals, Flatiron Health, GlaxoSmithKline, Incyte, Partners Therapeutics, Partners Therapeutics, Pfizer Speakers' Bureau: AbbVie, Merck, TakedaJohn F. DiPersioStock and Other Ownership Interests: Magenta Therapeutics, Wugen Honoraria: Incyte Consulting or Advisory Role: Cellworks, Rivervest, Magenta Therapeutics, Incyte Research Funding: Amphivena Therapeutics (Inst), Macrogenics (Inst), Incyte (Inst), Wugen (Inst), BiolineRx (Inst), Maxcyte (Inst), Bigelow Aerospace (Inst) Patents, Royalties, Other Intellectual Property: Patents: CD7 and CD2 knockout for CART to CD7 and CDL; Duvelisib for treatment of cytokine release syndrome; NT-17 to enhance CART survival; Novel WU mobilizing compounds (Inst); Selection of IMPDH mutant stem cells; IFNγ, upregulate MHCII for relapsed AML; Dextran-based molecules to detect CAR-T cells; Combining integrin inhibitor with chemokine binders, 016131; JAK and calcineurin inhibition, solid organ transplant; VLA4, gro-b; Triple combination–CXCR2, VLA-4, gro-b; Targeting IFNR/CSCR3 in GvHD; WU/SLU compounds VLA4 and CXCR2 (Inst) Travel, Accommodations, Expenses: Incyte, Macrogenics, Magenta TherapeuticsMary C. PolitiResearch Funding: MerckDavid H. SpencerConsulting or Advisory Role: Wugen Research Funding: IlluminaEric J. DuncavageStock and Other Ownership Interests: P&V Licensing Consulting or Advisory Role: Cofactor Genomics, Bristol Myers Squibb, Eli Lilly Open Payments Link: https://openpaymentsdata.cms.gov/physician/317379Timothy J. LeyResearch Funding: Rigel Patents, Royalties, Other Intellectual Property: Licenses for monoclonal antibodies and recombinant granzymesMeagan A. JacobyHonoraria: Takeda Research Funding: Geron (Inst), AbbVie (Inst), Jazz Pharmaceuticals (Inst), Aprea AB (Inst), Amphivena (Inst), Janssen (Inst) No other potential conflicts of interest were reported., (© 2021 by American Society of Clinical Oncology.)

Natural killer (NK) cells are an emerging cancer cellular therapy and potent mediators of antitumor immunity. Cytokine-induced memory-like (ML) NK cellular therapy is safe and induces remissions in patients with acute myeloid leukemia (AML). However, the dynamic changes in phenotype that occur after NK-cell transfer that affect patient outcomes remain unclear. Here, we report comprehensive multidimensional correlates from ML NK cell-treated patients with AML using mass cytometry. These data identify a unique in vivo differentiated ML NK-cell phenotype distinct from conventional NK cells. Moreover, the inhibitory receptor NKG2A is a dominant, transcriptionally induced checkpoint important for ML, but not conventional NK-cell responses to cancer. The frequency of CD8α + donor NK cells is negatively associated with AML patient outcomes after ML NK therapy. Thus, elucidating the multidimensional dynamics of donor ML NK cells in vivo revealed critical factors important for clinical response, and new avenues to enhance NK-cell therapeutics. SIGNIFICANCE: Mass cytometry reveals an in vivo memory-like NK-cell phenotype, where NKG2A is a dominant checkpoint, and CD8α is associated with treatment failure after ML NK-cell therapy. These findings identify multiple avenues for optimizing ML NK-cell immunotherapy for cancer and define mechanisms important for ML NK-cell function. This article is highlighted in the In This Issue feature, p. 1775 ., (©2020 American Association for Cancer Research.)

For patients with relapsed or refractory classical Hodgkin lymphoma (cHL), salvage chemotherapy followed by consolidation with autologous stem cell transplant (ASCT) remains the standard of care. Even with this aggressive treatment strategy, 5-year progression-free survival is ≤50%, and there remains interest in maintenance strategies to improve long-term disease-free survival. Lenalidomide is an immunomodulatory agent with demonstrated activity in multiple subtypes of lymphoma including cHL, and has also been shown to improve both progression-free and overall survival as maintenance therapy after ASCT in multiple myeloma. This multicenter study evaluated maintenance lenalidomide after ASCT for patients with cHL. Patients were enrolled 60 to 90 days post-transplant and received oral lenalidomide on days 1 to 28 of 28-day cycles for a maximum of 18 cycles. Lenalidomide was started at 15 mg daily and increased to maximum of 25 mg daily if tolerated. The primary objective of this study was to assess the feasibility of this regimen, with a goal <30% rate of discontinuation at or before cycle 12 for drug-related reasons. Twenty-seven patients were enrolled and 26 received at least 1 dose of lenalidomide. With a median follow-up of 51.3 months (range, 12.2 to 76.2 months), 23 of 26 patients were alive. Median event-free survival was 9.4 months and median progression-free survival had not been reached, with 17 of 26 patients (65.4%) remaining in remission at last follow-up. Excluding 4 patients who discontinued therapy for progression and 2 who discontinued due to noncompliance, the discontinuation rate at or before cycle 12 was 52%. Treatment was complicated by a high frequency of hematologic adverse events, with 15 patients (58%) experiencing grade 3 to 4 hematologic toxicity and 5 (19%) experiencing grade 4 hematologic toxicity. We conclude that the regimen of maintenance lenalidomide explored in this study is not feasible for patients with cHL immediately following ASCT. An alternative lenalidomide dose or schedule may be better tolerated following ASCT for patients with relapsed or refractory cHL., (Copyright © 2020 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc. All rights reserved.)

Background: Allogeneic hematopoietic stem-cell transplantation is the only curative treatment for patients with myelodysplastic syndrome (MDS). The molecular predictors of disease progression after transplantation are unclear., Methods: We sequenced bone marrow and skin samples from 90 adults with MDS who underwent allogeneic hematopoietic stem-cell transplantation after a myeloablative or reduced-intensity conditioning regimen. We detected mutations before transplantation using enhanced exome sequencing, and we evaluated mutation clearance by using error-corrected sequencing to genotype mutations in bone marrow samples obtained 30 days after transplantation. In this exploratory study, we evaluated the association of a mutation detected after transplantation with disease progression and survival., Results: Sequencing identified at least one validated somatic mutation before transplantation in 86 of 90 patients (96%); 32 of these patients (37%) had at least one mutation with a maximum variant allele frequency of at least 0.5% (equivalent to 1 heterozygous mutant cell in 100 cells) 30 days after transplantation. Patients with disease progression had mutations with a higher maximum variant allele frequency at 30 days than those who did not (median maximum variant allele frequency, 0.9% vs. 0%; P<0.001). The presence of at least one mutation with a variant allele frequency of at least 0.5% at day 30 was associated with a higher risk of progression (53.1% vs. 13.0%; conditioning regimen-adjusted hazard ratio, 3.86; 95% confidence interval [CI], 1.96 to 7.62; P<0.001) and a lower 1-year rate of progression-free survival than the absence of such a mutation (31.3% vs. 59.3%; conditioning regimen-adjusted hazard ratio for progression or death, 2.22; 95% CI, 1.32 to 3.73; P=0.005). The rate of progression-free survival was lower among patients who had received a reduced-intensity conditioning regimen and had at least one persistent mutation with a variant allele frequency of at least 0.5% at day 30 than among patients with other combinations of conditioning regimen and mutation status (P≤0.001). Multivariate analysis confirmed that patients who had a mutation with a variant allele frequency of at least 0.5% detected at day 30 had a higher risk of progression (hazard ratio, 4.48; 95% CI, 2.21 to 9.08; P<0.001) and a lower 1-year rate of progression-free survival than those who did not (hazard ratio for progression or death, 2.39; 95% CI, 1.40 to 4.09; P=0.002)., Conclusions: The risk of disease progression was higher among patients with MDS in whom persistent disease-associated mutations were detected in the bone marrow 30 days after transplantation than among those in whom these mutations were not detected. (Funded by the Leukemia and Lymphoma Society and others.).

Allogeneic hematopoietic cell transplantation (alloHCT) is a potentially curative treatment for myelodysplastic syndromes (MDS), but patients who relapse after transplant have poor outcomes. In order to understand the contribution of tumor clonal evolution to disease progression,we applied exome and error-corrected targeted sequencing coupled with copy number analysis to comprehensively define changes in the clonal architecture of MDS in response to therapy using 51 serially acquired tumor samples from 9 patients who progressed after an alloHCT. We show that small subclones before alloHCT can drive progression after alloHCT. Notably, at least one subclone expanded or emerged at progression in all patients. Newly acquired structural variants (SVs) were present in an emergent/expanding subclone in 8 of 9 patients at progression, implicating the acquisition of SVs as important late subclonal progression events. In addition, pretransplant therapy with azacitidine likely influenced the mutation spectrum and evolution of emergent subclones after alloHCT. Although subclone evolution is common, founding clone mutations are always present at progression and could be detected in the bone marrow as early as 30 and/or 100 days after alloHCT in 6 of 8 (75%) patients, often prior to clinical progression. In conclusion, MDS progression after alloHCT is characterized by subclonal expansion and evolution, which can be influenced by pretransplant therapy.

Decitabine has been explored as a reduced-intensity therapy for older or unfit patients with acute myeloid leukemia (AML). To better understand the risk of infections during decitabine treatment, we retrospectively examined the culture results from each infection-related serious adverse event that occurred among 85 AML and myelodysplastic syndromes (MDS) patients treated in a prospective clinical study using 10-day cycles of decitabine at Washington University School of Medicine. Culture results were available for 163 infection-related complications that occurred in 70 patients: 90 (55.2%) events were culture-negative, 32 (19.6%) were gram-positive bacteria, 20 (12.3%) were gram-negative bacteria, 12 (7.4%) were mixed, 6 (3.7%) were viral, 2 (1.2%) were fungal, and 1 (0.6%) was mycobacterial. Infection-related mortality occurred in 3/24 (13%) of gram-negative events, and 0/51 gram-positive events. On average, nearly one third of patients experienced an infection-related complication with each cycle, and the incidence did not decrease during later cycles. In summary, in patients receiving 10-day decitabine, infectious complications are common and may occur during any cycle of therapy. Although febrile events are commonly culture-negative, gram-positive infections are the most frequent source of culture-positive infections, but gram-negative infections represent a significant risk of mortality in AML and MDS patients treated with decitabine., (© 2017 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.)

Background: The molecular determinants of clinical responses to decitabine therapy in patients with acute myeloid leukemia (AML) or myelodysplastic syndromes (MDS) are unclear., Methods: We enrolled 84 adult patients with AML or MDS in a single-institution trial of decitabine to identify somatic mutations and their relationships to clinical responses. Decitabine was administered at a dose of 20 mg per square meter of body-surface area per day for 10 consecutive days in monthly cycles. We performed enhanced exome or gene-panel sequencing in 67 of these patients and serial sequencing at multiple time points to evaluate patterns of mutation clearance in 54 patients. An extension cohort included 32 additional patients who received decitabine in different protocols., Results: Of the 116 patients, 53 (46%) had bone marrow blast clearance (<5% blasts). Response rates were higher among patients with an unfavorable-risk cytogenetic profile than among patients with an intermediate-risk or favorable-risk cytogenetic profile (29 of 43 patients [67%] vs. 24 of 71 patients [34%], P<0.001) and among patients with TP53 mutations than among patients with wild-type TP53 (21 of 21 [100%] vs. 32 of 78 [41%], P<0.001). Previous studies have consistently shown that patients with an unfavorable-risk cytogenetic profile and TP53 mutations who receive conventional chemotherapy have poor outcomes. However, in this study of 10-day courses of decitabine, neither of these risk factors was associated with a lower rate of overall survival than the rate of survival among study patients with intermediate-risk cytogenetic profiles., Conclusions: Patients with AML and MDS who had cytogenetic abnormalities associated with unfavorable risk, TP53 mutations, or both had favorable clinical responses and robust (but incomplete) mutation clearance after receiving serial 10-day courses of decitabine. Although these responses were not durable, they resulted in rates of overall survival that were similar to those among patients with AML who had an intermediate-risk cytogenetic profile and who also received serial 10-day courses of decitabine. (Funded by the National Cancer Institute and others; ClinicalTrials.gov number, NCT01687400 .).

Myelodysplastic syndromes (MDS) are clonal hematopoietic disorders characterized by bone marrow failure which frequently progress to acute myeloid leukemia. Patients who fail to respond to, or progress on first-line DNA hypomethylating agents (HMA) have a poor prognosis. Conventionally dosed lenalidomide has activity in 5q-MDS. In other subtypes, it may reduce RBC transfusion requirements but does not result in cytogenetic responses. We previously reported that high-dose lenalidomide induction (50 mg/day) results in complete remissions in a high fraction of patients. We, therefore, conducted a Phase 2 trial of the same regimen in MDS refractory to HMA. Marrow complete remissions were seen in 33% of patients and hematological improvement in 8% of patients. Significant infections complicated more than 50% of cases. Future trials to explore alternative dosing schedules of high-dose lenalidomide to increase efficacy while decreasing toxicity are warranted.

Recent whole-genome sequencing (WGS) studies have demonstrated that tumors typically comprise a founding clone and multiple subclones (i.e., clonal heterogeneity is common). The possible combination of mutations in each tumor clone is enormous, making each tumor genetically unique. Clonal heterogeneity likely has a role in cancer progression, relapse, metastasis, and chemoresistance due to functional differences in genetically unique subclones. In current clinical practice, gene mutations are only classified as being present or absent, ignoring the clonal complexity of cancers. In this review, we address how tumor clonality is measured using next-generation sequencing (NGS) data, highlight that clonal heterogeneity is common across multiple tumor types, and discuss the potential clinical implications of tumor clonal heterogeneity., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Clofarabine has shown activity and tolerability in older patients with acute myeloid leukemia (AML). We investigated the safety and tolerability of an oral formulation of clofarabine for consolidation therapy of patients aged 60 and older with AML. In this phase I study, twenty-two patients older than 60 years with AML in first complete remission were treated once daily with oral clofarabine for 14 or 21 days of a 28-day cycle, for up to five cycles. Dose escalation from 1 mg to 6 mg daily using a 3 + 3 design was used to determine dose-limiting toxicities (DLT), the maximum tolerated dose (MTD), and tolerability of oral clofarabine. No DLTs or Grade 3-4 nonhematologic toxicities were observed. The primary toxicities were hematologic, including uncomplicated grade 3-4 neutropenia (50%) and thrombocytopenia (50%). Given that myelosuppression necessitating dose delays/reductions was observed more commonly at higher doses, the recommended phase II dose is 2 mg daily for 21 of 28 days. At doses equal to or greater than 2 mg, the median relapse-free survival was 28.35 months. Oral clofarabine was well-tolerated with encouraging activity in patients older than 60 years. Further investigation of oral clofarabine as a consolidation and/or maintenance therapy in AML for older individuals is warranted. (ClinicalTrials.gov:NCT00727766)., (Copyright © 2014 Wiley Periodicals, Inc.)

Altered microRNA (miRNA) expression is frequently observed in acute myelogenous leukemia (AML) and has been implicated in leukemic transformation. Whether somatic copy number alterations (CNAs) are a frequent cause of altered miRNA gene expression is largely unknown. Herein, we used comparative genomic hybridization with a custom high-resolution miRNA-centric array and/or whole-genome sequence data to identify somatic CNAs involving miRNA genes in 113 cases of AML, including 50 cases of de novo AML, 18 cases of relapsed AML, 15 cases of secondary AML following myelodysplastic syndrome, and 30 cases of therapy-related AML. We identified a total of 48 somatic miRNA gene-containing CNAs that were not identified by routine cytogenetics in 20 patients (18%). All these CNAs also included one or more protein coding genes. We identified a single case with a hemizygous deletion of MIR223, resulting in the complete loss of miR-223 expression. Three other cases of AML were identified with very low to absent miR-223 expression, an miRNA gene known to play a key role in myelopoiesis. However, in these cases, no somatic genetic alteration of MIR223 was identified, suggesting epigenetic silencing. These data show that somatic CNAs specifically targeting miRNA genes are uncommon in AML.

Chromosomal deletions and amplifications that occur in affected cells from patients with myelodysplastic syndromes and acute myeloid leukemia often contain genes that contribute to disease pathogenesis. Identification of copy number alterations (deletions and amplifications) and regions of copy neutral loss of heterozygosity using array-based platforms has led to the identification of genes that are commonly mutated in myeloid malignancies. In this article, we review the literature and highlight the array-based studies that directly compare matched normal and tumor samples from the same individual to identify somatic alterations. We also discuss the use of next-generation sequencing to identify all types of structural variants, including copy number alterations and copy neutral loss of heterozygosity, and provide an outlook for how this technology may be used to interrogate cancer genomes.

Murine gammaherpesvirus 68 (MHV68) infection of inbred mice represents a genetically tractable small-animal model for assessing the requirements for the establishment of latency, as well as reactivation from latency, within the lymphoid compartment. By day 16 postinfection, MHV68 latency in the spleen is found in B cells, dendritic cells, and macrophages. However, as with Epstein-Barr virus, by 3 months postinfection MHV68 latency is predominantly found in isotype-switched memory B cells. The MHV68 M2 gene product is a latency-associated antigen with no discernible homology to any known cellular or viral proteins. However, depending on experimental conditions, the M2 protein has been shown to play a critical role in both the efficient establishment of latency in splenic B cells and reactivation from latently infected splenic B cells. Inspection of the sequence of the M2 protein reveals several hallmarks of a signaling molecule, including multiple PXXP motifs and two potential tyrosine phosphorylation sites. Here, we report the generation of a panel of recombinant MHV68 viruses harboring mutations in the M2 gene that disrupt putative functional motifs. Subsequent analyses of the panel of M2 mutant viruses revealed a functionally important cluster of PXXP motifs in the C-terminal region of M2, which have previously been implicated in binding Vav proteins (P. A. Madureira, P. Matos, I. Soeiro, L. K. Dixon, J. P. Simas, and E. W. Lam, J. Biol. Chem. 280:37310-37318, 2005; L. Rodrigues, M. Pires de Miranda, M. J. Caloca, X. R. Bustelo, and J. P. Simas, J. Virol. 80:6123-6135, 2006). Further characterization of two adjacent PXXP motifs in the C terminus of the M2 protein revealed differences in the functions of these domains in M2-driven expansion of primary murine B cells in culture. Finally, we show that tyrosine residues 120 and 129 play a critical role in both the establishment of splenic latency and reactivation from latency upon explant of splenocytes into tissue culture. Taken together, these analyses will aide future studies for identifying M2 interacting partners and B-cell signaling pathways that are manipulated by the M2 protein.

Human gammaherpesvirus infections are associated with development of lymphoproliferative disease. Understanding of the mechanisms of gammaherpesvirus lymphomagenesis during chronic infection in a natural host has been limited by the exquisite species specificity of human gammaherpesviruses and the expense of primates. Murine gammaherpesvirus gammaHV68 is genetically and biologically related to human gammaherpesviruses and herpesvirus saimiri and has been reported to be associated with lymphoproliferative disease in mice (N. P. Sunil-Chandra, J. Arno, J. Fazakerley, and A. A. Nash, Am. J. Pathol. 145:818-826, 1994). We report the development of an animal model of gammaHV68 lymphomagenesis in BALB/c beta2 microglobulin-deficient mice (BALB beta2m-/-). GammaHV68 infection induced two lymphoproliferative lesions: B-cell lymphoma and atypical lymphoid hyperplasia (ALH). ALH lesion histology resembled lesions of Epstein-Barr virus-associated posttransplant lymphoproliferative disease and was characterized by the abnormal infiltration of the white pulp with cells expressing the plasma cell marker CD138. Lymphomas observed in gammaHV68-infected animals were B220+/CD3- large-cell lymphomas. GammaHV68-infected cells were common in ALH lesions as measured by in situ hybridization with a probe specific for viral tRNAs (vtRNAs), but they were scarce in gammaHV68-infected spleens with normal histology. Unlike ALH lesions, gammaHV68 vtRNA-positive cells were rare in lymphomas. GammaHV68 infection of BALB beta2m-/- mice results in lymphoproliferation and lymphoma, providing a valuable tool for identifying viral and host genes involved in gammaherpesvirus-associated malignancies. Our findings suggest that gammaHV68 induces lymphomas via hit-and-run oncogenesis, paracrine effects, or stimulation of chronic inflammation.

Murine gammaherpesvirus 68 (gammaHV68) infection of mice provides a tractable small-animal model system for assessing the requirements for the establishment and maintenance of gammaherpesvirus latency within the lymphoid compartment. The M2 gene product of gammaHV68 is a latency-associated antigen with no discernible homology to any known proteins. Here we focus on the requirement for the M2 gene in splenic B-cell latency. Our analyses showed the following. (i) Low-dose (100 PFU) inoculation administered via the intranasal route resulted in a failure to establish splenic B-cell latency at day 16 postinfection. (ii) Increasing the inoculation dose to 4 x 10(5) PFU administered via the intranasal route partially restored the establishment of B-cell latency at day 16, but no virus reactivation was detected upon explant into tissue cultures. (iii) Although previous data failed to detect a phenotype of the M2 mutant upon high-dose intraperitoneal inoculation, decreasing the inoculation dose to 100 PFU administered intraperitoneally revealed a splenic B-cell latency phenotype at day 16 that was very similar to the phenotype observed upon high-dose intranasal inoculation. (iv) After low-dose intraperitoneal inoculation, fractionated B-cell populations showed that the M2 mutant virus was able to establish latency in surface immunoglobulin D-negative (sIgD(-)) B cells; by 6 months postinfection, equivalent frequencies of M2 mutant and marker rescue viral genome-positive sIgD(-) B cells were detected. (v) Like the marker rescue virus, the M2 mutant virus also established latency in splenic naive B cells upon low-dose intraperitoneal inoculation, but there was a significant lag in the decay of this latently infected reservoir compared to that seen with the marker rescue virus. (vi) After low-dose intranasal inoculation, by day 42 postinfection, latency was observed in the spleen, although at a frequency significantly lower than that in the marker rescue virus-infected mice; by 3 months postinfection, nearly equivalent levels of viral genome-positive cells were observed in the spleens of marker rescue virus- and M2 mutant virus-infected mice, and these cells were exclusively sIgD(-) B cells. Taken together, these data convincingly demonstrate a role for the M2 gene product in reactivation from splenic B cells and also suggest that disruption of the M2 gene leads to dose- and route-specific defects in the efficient establishment of splenic B-cell latency.

Gammaherpesviruses such as Epstein-Barr virus and Kaposi's sarcoma-associated herpesvirus are important human pathogens that establish long-term latent infections. Understanding of the initiation and maintenance of latent infections has important implications for the prevention and treatment of gammaherpesvirus-related diseases. Although much is known about gammaherpesvirus pathogenesis, it is unclear how the infectious dose of a virus influences its ability to establish latent infection. To examine the relationship between the infectious dose and gammaherpesvirus latency, we inoculated wild-type mice with 0.01 to 10(6) PFU of murine gammaherpesvirus 68 (gammaHV68) and quantitatively measured latency and acute-phase replication. Surprisingly, during latency, the frequencies of ex vivo reactivation were similar over a 10(7)-fold range of doses for i.p. infection and over a 10(4)-fold range of doses for intranasal infection. Further, the frequencies of cells harboring viral genome during latency did not differ substantially over similar dose ranges. Although the kinetics of acute-phase replication were delayed at small doses of virus, the peak titer did not differ significantly between mice infected with a large dose of virus and those infected with a small dose of virus. The results presented here indicate that any initiation of infection leads to substantial acute-phase replication and subsequent establishment of a maximal level of latency. Thus, infections with doses as small as 0.1 PFU of gammaHV68 result in stable levels of acute-phase replication and latent infection. These results demonstrate that the equilibrium level of establishment of gammaherpesvirus latency is independent of the infectious dose and route of infection.

Infection of mice with murine gammaherpesvirus 68 (gamma HV68; also referred to as MHV68) provides a tractable small-animal model with which to address the requirements for the establishment and maintenance of gammaherpesvirus infection in vivo. The M2 gene of gamma HV68 is a latency-associated gene that encodes a protein lacking discernible homology to any known viral or cellular proteins. M2 gene transcripts have been detected in latently infected splenocytes (S. M. Husain, E. J. Usherwood, H. Dyson, C. Coleclough, M. A. Coppola, D. L. Woodland, M. A. Blackman, J. P. Stewart, and J. T. Sample, Proc. Natl. Acad. Sci. USA 96:7508-7513, 1999; H. W. Virgin IV, R. M. Presti, X. Y. Li, C. Liu, and S. H. Speck, J. Virol. 73:2321-2332, 1999) and peritoneal exudate cells (H. W. Virgin IV, R. M. Presti, X. Y. Li, C. Liu, and S. H. Speck, J. Virol. 73:2321-2332, 1999), as well as in a latently gamma HV68-infected B-lymphoma cell line (S. M. Husain, E. J. Usherwood, H. Dyson, C. Coleclough, M. A. Coppola, D. L. Woodland, M. A. Blackman, J. P. Stewart, and J. T. Sample, Proc. Natl. Acad. Sci. USA 96:7508-7513, 1999). Here we describe the generation of gamma HV68 mutants with disruptions in the M2 gene. Mutation of the M2 gene did not affect the ability of the virus to replicate in tissue culture, nor did it affect gamma HV68 virulence in B6.Rag1 deficient mice. However, we found that M2 was differentially required for acute replication in vivo. While mutation of M2 did not affect acute phase of virus replication in the lungs of mice following intranasal inoculation, acute-phase virus replication in the spleen was decreased compared to that of the wild-type and marker rescue viruses following intraperitoneal inoculation. Upon intranasal inoculation, M2 mutant viruses exhibited a significant decrease in the establishment of latency in the spleen on day 16 postinfection, as measured by the frequency of viral genome-positive cells. In addition, M2 mutant viral genome-positive cells reactivated from latency inefficiently compared to wild-type and marker rescue viruses. By day 42 after intranasal inoculation, the frequencies of M2 mutant and wild-type viral genome-positive cells were nearly equivalent and little reactivation was detected from either population. In sharp contrast to the results obtained following intranasal inoculation, after intraperitoneal inoculation, no significant defect was observed in the establishment or reactivation from latency with the M2 mutant viruses. These results indicate that the requirements for the establishment of latency are affected by the route of infection.