Wu, Yue-Zhong

Abstract Monoclonal B-cell lymphocytosis (MBL) progresses to chronic lymphocytic leukemia (CLL) requiring therapy at 1% to 5% per year. Improved prediction of progression would greatly benefit individuals with MBL. Patients with CLL separate into 3 distinct epigenetic subtypes (epitypes) with high prognostic significance, and recently the intermediate epitype has been shown to be enriched for high-risk immunoglobulin lambda variable (IGLV) 3-21 rearrangements, impacting outcomes for these patients. Here, we employed this combined strategy to generate the epigenetic and light chain immunoglobulin (ELCLV3-21) signature to classify 219 individuals with MBL. The ELCLV3-21 high-risk signature distinguished MBL individuals with a high probability of progression (39.9% and 71.1% at 5 and 10 years, respectively). ELCLV3-21 improved the accuracy of predicting time to therapy for individuals with MBL compared with other established prognostic indicators, including the CLL international prognostic index (c-statistic, 0.767 vs 0.668, respectively). Comparing ELCLV3-21 risk groups in MBL vs a cohort of 226 patients with CLL revealed ELCLV3-21 high-risk individuals with MBL had significantly shorter time to therapy (P = .003) and reduced overall survival (P = .03) compared with ELCLV3-21 low-risk individuals with CLL. These results highlight the power of the ELCLV3-21 approach to identify individuals with a higher likelihood of adverse clinical outcome and may provide a more accurate approach to classify individuals with small B-cell clones.

Monoclonal B cell lymphocytosis (MBL) has been shown to be the precursor condition that precedes overt diagnosis of chronic lymphocytic leukemia (CLL). Whereas CLL is classified with greater than or equal to 5 × 109/L B lymphocytes in the peripheral blood, MBL is a clonal expansion of B-cells below this threshold. MBL can be further divided into high- or low-count based on whether the B-cell count is above or below 0.5 × 109/L. Approximately 10% of the population over 40 is estimated to have MBL, increasing to >50% over the age of 90. While low-count MBL is unlikely to progress, 1-2% of high-count (HC) MBL individuals progress to CLL requiring therapy per year. It is debatable if all patients with detectable MBL should be classified as an entity requiring monitoring by a hematologist, especially for low-count MBL. In addition, the diagnosis of leukemia is distressing to patients; therefore, it is important to identify HC MBL patients that are more likely to progress to disease requiring treatment and thus should be monitored more closely. As the majority of MBL cases phenotypically resemble CLL, established prognostic markers including recurrent chromosomal aberrations, beta-2 microglobulin levels, and the mutational status of the Immunoglobulin heavy-chain variable region locus (IGHV) have been shown to predict time to treatment (TTT) and overall survival (OS) in a large retrospective study of MBL1. CLL patients can also be divided into three distinct epigenetic subtypes that reflect progressive DNA methylation changes that occurs during B cell development. These 'epitypes' termed low-programmed (LP), intermediate-programmed (IP), and high-programmed (HP) independently predict clinical outcomes irrespective of disease stage and treatment2. LP-CLL patients follow a generally unfavorable clinical course compared to the more indolent HP-CLL patients, while IP CLL patients display an intermediate outcome. Here we sought to determine if epitype forecasts progression to CLL and eventual clinical outcome for individuals with MBL. We analyzed 66 individuals diagnosed with HC MBL at the Mayo Clinic with a median follow-up of 6.3 years. Developmental epitype was determined using our novel Methylation-iPLEX technique that interrogates 34 CpGs and assigns epitype using a random forest model2. Seventy-seven percent of the MBL cases were assigned to one of the three epitypes: 42.4% HP, 19.7% IP, and 15.2% LP. The residual 23% remained unclassified due to ambiguous (low confidence) epigenetic patterns or insufficient purity (Figure 1A). The overall proportion of HP and IP epitypes in MBL were significantly greater than proportions observed in CLL cohorts (P<0.01). Epitypes remained stable over time as 20/21 cases for which we obtained a high-confidence epitype classification at multiple time points remained unchanged. Epitype significantly predicted MBL individuals progressing to treatment (P=0.001) with LP individuals progressing in a median of 5.6 years (P=0.049 and P=0.0002 versus IP and HP, respectively); median was not reached in HP or IP (Figure 1B). Epitype also predicted overall survival (OS) in MBL (P=0.04), with LP individuals having a significantly shorter OS (median of 11 years versus not reached in IP and HP; P=0.056 and P=0.048 versus IP and HP, respectively). In this study we evaluated a cohort of 66 HC MBL cases and determined that classification using developmental DNA methylation epitypes can be employed in HC MBL to aid in risk stratification. HC MBL patients classified as LP are more likely to progress to requiring treatment and have a significantly reduced OS. The epigenetic classification may help clinicians decide how closely and frequently a HC MBL individual needs to be monitored. Figure 1: (A) Breakdown of the epigenetic subtype assigned to 66 HC MBL samples. (B) Kaplan-Meier analysis of time to treatment and (C) overall survival of MBL patients separated by epitype. 1. Parikh, S. A. et al. Outcomes of a large cohort of individuals with clinically ascertained high-count monoclonal B-cell lymphocytosis. Haematologica103, e237-e240 (2018). 2. Giacopelli, B. et al. Developmental subtypes assessed by DNA methylation-iPLEX forecast the natural history of chronic lymphocytic leukemia. Blood blood.2019000490 (2019). doi:10.1182/blood.2019000490 Disclosures Byrd: Ohio State University: Patents & Royalties: OSU-2S; Janssen: Consultancy, Other: Travel Expenses, Research Funding, Speakers Bureau; BeiGene: Research Funding; TG Therapeutics: Other: Travel Expenses, Research Funding, Speakers Bureau; Novartis: Other: Travel Expenses, Speakers Bureau; TG Therapeutics: Other: Travel Expenses, Research Funding, Speakers Bureau; Genentech: Research Funding; Gilead: Other: Travel Expenses, Research Funding, Speakers Bureau; Novartis: Other: Travel Expenses, Speakers Bureau; Ohio State University: Patents & Royalties: OSU-2S; Gilead: Other: Travel Expenses, Research Funding, Speakers Bureau; Acerta: Research Funding; Genentech: Research Funding; Pharmacyclics LLC, an AbbVie Company: Other: Travel Expenses, Research Funding, Speakers Bureau; Pharmacyclics LLC, an AbbVie Company: Other: Travel Expenses, Research Funding, Speakers Bureau; Acerta: Research Funding. Shanafelt:Patent: Patents & Royalties: US14/292,075 on green tea extract epigallocatechin gallate in combination with chemotherapy for chronic lymphocytic leukemia; Merck: Research Funding; Polyphenon E International: Research Funding; Pharmacyclics: Research Funding; Genentech: Research Funding; Hospira: Research Funding; Glaxo-SmithKline: Research Funding; Abbvie: Research Funding; Cephalon: Research Funding; Celgene: Research Funding. Parikh:Genentech: Honoraria; Janssen: Research Funding; AstraZeneca: Honoraria, Research Funding; Pharmacyclics: Honoraria, Research Funding; MorphoSys: Research Funding; AbbVie: Honoraria, Research Funding; Acerta Pharma: Research Funding; Ascentage Pharma: Research Funding. Kay:Agios: Other: DSMB; MorphoSys: Other: Data Safety Monitoring Board; Infinity Pharmaceuticals: Other: DSMB; Celgene: Other: Data Safety Monitoring Board.

Abstract In CN-AML, mutations of specific genes have prognostic significance and are used for treatment guidance. However, these mutations are in general not mutually exclusive and CN-AML patients (pts) frequently harbor mutational combinations with unclear prognostic significance because of the concurrent presence of mutations with favorable (CEBPA, NPM1) and unfavorable (ASXL1, DNMT3A, IDH1, IDH2, FLT3-ITD, MLL-PTD, RUNX1, TET2, WT1) impact on outcome. Here, we report the frequency and clinical significance of isolated mutations and their combinations in 364 CN-AML pts. Younger [<60 years (y); n=163] and older (≥60 y; n=201) pts were intensively treated on frontline CALGB/Alliance protocols and, per protocol, did not undergo allogeneic stem cell transplantation in first complete remission (CR). Median follow-up for pts alive was 8.7 y. Pts were analyzed centrally for mutations in the ASXL1, CEBPA, DNMT3A, IDH1, IDH2, NPM1, RUNX1, TET2, and WT1 genes and the presence of FLT3-ITD, FLT3-TKD and MLL-PTD. We found that 99% of pts had ≥1 and 88% ≥2 of the 12 mutations. Specifically, 11% of pts had 1 gene mutated (n1), 40% had 2 (n2), 31% 3 (n3), and 18% harbored ≥4 mutated genes (n4). The distribution of the different n groups in younger and older pts was similar (Fig 1). The expected frequency of each mutated gene in every numerical (n) group was calculated as follows: [no. of pts with the mutated gene] x [total no. of mutations in the n group] / [total no. of mutations in all pts], and compared with the observed frequency. CEBPA, IDH2, NPM1, and RUNX1 mutations were overrepresented in the n1 and n2 groups (P<.001, P<.001, P=.002, P=.02, respectively) and thus likely represent “early” events in leukemogenesis. In contrast, DNMT3A, FLT3-ITD, and TET2 mutations were more frequent in the n3 and n4 groups (P=.008, P<.001, P=.02, respectively) suggesting that they are likely “late” events. The distribution among age groups and clinical impact of the “early” mutations (i.e., CEBPA, NPM1, IDH2) presenting as isolated mutations or in combination with other mutations were then investigated. Isolated RUNX1 mutations could not be evaluated due to small sample size. Younger pts were more likely to harbor an isolated “early” mutated gene than older pts (21% v 12%, P=.03). Specifically, isolated CEBPA and NPM1 mutations were more frequent in younger pts compared with the older (7% v 2%, P=.007; 7% v 3%, P=.07, respectively). In pts with isolated CEBPA mutations, these were always bi-allelic. Single “early” mutated genes varied in their impact on CR achievement (CEBPA: 100%, NPM1: 94%, IDH2: 67%), and overall survival (OS; 3-y OS: CEBPA: 87%, NPM1: 69%, IDH2: 22%). Acquisition of additional mutations adversely modified the prognostic significance of favorable “early” mutations in the CEBPA (Fig 2A) and NPM1 (Fig 2B) genes, but left unchanged the unfavorable effect of IDH2 mutations (Fig 2C). Two mutational combinations were exceptions to this: younger pts with both NPM1 and DNMT3A mutations (8 pts) had an excellent prognosis with 3-y OS of 100%; and older pts with concurrent NPM1 and IDH2 mutations (9 pts; all IDH2 mutations were in codon R140) had a high 3-y OS rate of 67%. We conclude that CEBPA and NPM1 mutations mainly define pts with favorable prognosis when they present as single markers, whereas mutated IDH2 predominantly associates with adverse outcome. The NPM1+DNMT3A and NPM1+IDH2 mutational patterns may define novel favorable molecular subtypes in younger and older CN-AML pts, respectively, but these results require corroboration in larger pt cohorts. Disclosures: Mrózek: AMERICAN SOCIETY OF HEMATOLOGY: I will review abstracls submitted for presentation at the 55th ASH Annual Meeting in the 611 category Other. Eisfeld:AMERICAN SOCIETY OF HEMATOLOGY: I will review abstracls submitted for presentation at the 55th ASH Annual Meeting in the 608 category Other.

Abstract In chronic lymphocytic leukemia (CLL), it is recognized that germinal center experience by the cell-of-origin has an influence on the malignant phenotype and impacts clinical behavior. Measurement of the mutational status of the IGHV locus is a commonly used approach that subgroups patients according to this natural history. Other biomarkers correlating with these subgroups, such as ZAP70 expression and ZAP70 DNA methylation, are also used. Recently, we and others have found vast differences in global DNA methylation profiles among CLL cases that classifies distinct subgroups related to their natural history. Here we systematically evaluate various markers of natural history of the cell-of-origin for their ability to discriminate clinical outcomes. IGHV mutational status and ZAP70 expression are currently the most widely used prognostic markers of germinal center experience. These markers are generally concordant, with IGHV-unmutated associating with ZAP70 positivity. To compare their relative prognostic impact, we selected CLL cases from a large sample cohort collected as a prospective study maintained by the CLL Research Consortium that were discordant (IGHV-mutated and ZAP70(+) or IGHV-unmutated and ZAP70(-); n=192). We found a significant difference in time-to-first-treatment (TTFT; P=0.002) and overall survival (OS; P=0.032) between discordant groups, with curves separating according to IGHV as opposed to ZAP70 (Fig.1A). DNA methylation-based classification of CLL according to their natural history has not been compared to IGHV status. This classification strategy subgroups the majority of cases into low-programmed CLL (LP-CLL) or high-programmed (HP-CLL) subgroups that generally correlate with IGHV-unmutated/ZAP70(+) and IGHV-mutated/ZAP70(-), respectively, along with a minority of cases in an intermediate (IP-CLL) subgroup. We used our previously-described DNA methylation assay, based on MassARRAY interrogating 7 genomic loci including ZAP70, to group the 192 samples with discordant IGHV/ZAP70 results with 327 samples analyzed previously from the same cohort. DNA methylation (LP-CLL vs. HP-CLL) outperformed IGHV classification (unmutated vs. mutated) in terms of separating TTFT curves (n=432; LP-CLL vs. HP-CLL median difference=4.8 years, unmutated vs. mutated IGHV median difference=2.9 years) and OS curves (n=491; LP-CLL vs. HP-CLL median difference=12.9 years, unmutated vs. mutated IGHV median difference=6.8 years). To evaluate whether DNA methylation subgroups provide additional prognostic information to IGHV, we compared TTFT and OS within IGHV subtypes. We found that the ability of DNA methylation subgrouping to separate OS curves was maintained in the IGHV-unmutated subtype (P<0.001; Fig.1B) and TTFT in both IGHV-unmutated and mutated subtypes (P<0.001 and P=0.016, respectively). Conversely, IGHV subtypes did not significantly separate outcomes within DNA methylation subgroups (P>0.5 for all). Further investigation of the features of DNA methylation subgroups as defined revealed a strong bias in the frequency of several recurrent adverse prognostic somatic mutations. In particular 17p deletions and EGR2, SF3B1 and XPO1 mutations occurred frequently within the LP-CLL subgroup. We next explored whether the presence of each mutation correlated with clinical outcome within its corresponding DNA methylation subgroup, and found heterogenous results. EGR2 mutations separated TTFT in the LP-CLL subgroup (P=0.0009), but 17p, XPO1 and SF3B1 did not (P>0.3). This suggests that the cell-of-origin should be taken into account to accurately assess the clinical impact of somatic mutations. In summary, we demonstrate that among discordant cases for IGHV/ZAP70, IGHV appears to be a stronger prognostic factor for both TTFT and OS. When then evaluating the relative importance of DNA methylation subgrouping and IGHV status on TTFT and OS, we find that DNA methylation subgrouping is the more powerful prognostic factor. Among the markers of the cell-of-origin, DNA methylation is a strong tool for risk-stratifying patients and should be considered in development of risk prediction models. Figure 1. A) Kaplan-Meier analysis of TTFT of IGHV-mutated and ZAP70(+) versus IGHV-unmutated and ZAP70(-) (P=0.002, median difference=4.4 years). B) Kaplan-Meier analysis of OS in patients with unmutated IGHV separated by DNA methylation subgroup (P<0.001). Figure 1. A) Kaplan-Meier analysis of TTFT of IGHV-mutated and ZAP70(+) versus IGHV-unmutated and ZAP70(-) (P=0.002, median difference=4.4 years). B) Kaplan-Meier analysis of OS in patients with unmutated IGHV separated by DNA methylation subgroup (P<0.001). Disclosures Wierda: Acerta: Research Funding; Novartis: Research Funding; Gilead: Research Funding; Genentech: Research Funding; Abbvie: Research Funding. Brown:Infinity: Consultancy; Janssen: Consultancy; Gilead Sciences: Consultancy; Roche/Genentech: Consultancy; Celgene: Consultancy; Sun BioPharma: Consultancy; Pfizer: Consultancy; Abbvie: Consultancy. Kipps:Roche: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding; Gilead: Consultancy, Honoraria, Speakers Bureau; Pharmacyclics, LLC, an AbbVie Company: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria, Research Funding.

AbstractAlterations in global DNA methylation patterns are a major hallmark of cancer and represent attractive biomarkers for personalized risk stratification. Chronic lymphocytic leukemia (CLL) risk stratification studies typically focus on time to first treatment (TTFT), time to progression (TTP) after treatment, and overall survival (OS). Whereas TTFT risk stratification remains similar over time, TTP and OS have changed dramatically with the introduction of targeted therapies, such as the Bruton tyrosine kinase inhibitor ibrutinib. We have shown that genome-wide DNA methylation patterns in CLL are strongly associated with phenotypic differentiation and patient outcomes. Here, we developed a novel assay, termed methylation-iPLEX (Me-iPLEX), for high-throughput quantification of targeted panels of single cytosine guanine dinucleotides from multiple independent loci. Me-iPLEX was used to classify CLL samples into 1 of 3 known epigenetic subtypes (epitypes). We examined the impact of epitype in 1286 CLL patients from 4 independent cohorts representing a comprehensive view of CLL disease course and therapies. We found that epitype significantly predicted TTFT and OS among newly diagnosed CLL patients. Additionally, epitype predicted TTP and OS with 2 common CLL therapies: chemoimmunotherapy and ibrutinib. Epitype retained significance after stratifying by biologically related biomarkers, immunoglobulin heavy chain mutational status, and ZAP70 expression, as well as other common prognostic markers. Furthermore, among several biological traits enriched between epitypes, we found highly biased immunogenetic features, including IGLV3-21 usage in the poorly characterized intermediate-programmed CLL epitype. In summary, Me-iPLEX is an elegant method to assess epigenetic signatures, including robust classification of CLL epitypes that independently stratify patient risk at diagnosis and time of treatment.

Purpose To evaluate the impact of miR-155 on the outcome of adults with cytogenetically normal (CN) acute myeloid leukemia (AML) in the context of other clinical and molecular prognosticators and to gain insight into the leukemogenic role of this microRNA. Patients and Methods We evaluated 363 patients with primary CN-AML. miR-155 levels were measured in pretreatment marrow and blood by NanoString nCounter assays that quantified the expression of the encoding gene MIR155HG. All molecular prognosticators were assessed centrally. miR-155–associated gene and microRNA expression profiles were derived using microarrays. Results Considering all patients, high miR-155 expression was associated with a lower complete remission (CR) rate (P < .001) and shorter disease-free survival (P = .001) and overall survival (OS; P < .001) after adjusting for age. In multivariable analyses, high miR-155 expression remained an independent predictor for a lower CR rate (P = .007) and shorter OS (P < .001). High miR-155 expressers had approximately 50% reduction in the odds of achieving CR and 60% increase in the risk of death compared with low miR-155 expressers. Although high miR-155 expression was not associated with a distinct microRNA expression profile, it was associated with a gene expression profile enriched for genes involved in cellular mechanisms deregulated in AML (eg, apoptosis, nuclear factor-κB activation, and inflammation), thereby supporting a pivotal and unique role of this microRNA in myeloid leukemogenesis. Conclusion miR-155 expression levels are associated with clinical outcome independently of other strong clinical and molecular predictors. The availability of emerging compounds with antagonistic activity to microRNAs in the clinic provides the opportunity for future therapeutic targeting of miR-155 in AML.

Abstract The inv(16)(p13q22)/t(16;16)(p13;q22) in acute myeloid leukemia results in multiple CBFB-MYH11 fusion transcripts, with type A being most frequent. The biologic and prognostic implications of different fusions are unclear. We analyzed CBFB-MYH11 fusion types in 208 inv(16)/t(16;16) patients with de novo disease, and compared clinical and cytogenetic features and the KIT mutation status between type A (n = 182; 87%) and non–type A (n = 26; 13%) patients. At diagnosis, non–type A patients had lower white blood counts (P = .007), and more often trisomies of chromosomes 8 (P = .01) and 21 (P < .001) and less often trisomy 22 (P = .02). No patient with non–type A fusion carried a KIT mutation, whereas 27% of type A patients did (P = .002). Among the latter, KIT mutations conferred adverse prognosis; clinical outcomes of non–type A and type A patients with wild-type KIT were similar. We also derived a fusion-type–associated global gene-expression profile. Gene Ontology analysis of the differentially expressed genes revealed—among others—an enrichment of up-regulated genes involved in activation of caspase activity, cell differentiation and cell cycle control in non–type A patients. We conclude that non–type A fusions associate with distinctclinical and genetic features, including lack of KIT mutations, and a unique gene-expression profile.

AbstractRecently, we showed that increased miR-181a expression was associated with improved outcomes in cytogenetically normal acute myeloid leukemia (CN-AML). Interestingly, miR-181a expression was increased in CN-AML patients harboring CEBPA mutations, which are usually biallelic and associate with better prognosis. CEBPA encodes the C/EBPα transcription factor. We demonstrate here that the presence of N-terminal CEBPA mutations and miR-181a expression are linked. Indeed, the truncated C/EBPα-p30 isoform, which is produced from the N-terminal mutant CEBPA gene or from the differential translation of wild-type CEBPA mRNA and is commonly believed to have no transactivation activity, binds to the miR-181a-1 promoter and up-regulates the microRNA expression. Furthermore, we show that lenalidomide, a drug approved for myelodysplastic syndromes and multiple myeloma, enhances translation of the C/EBPα-p30 isoform, resulting in higher miR-181a levels. In xenograft mouse models, ectopic miR-181a expression inhibits tumor growth. Similarly, lenalidomide exhibits antitumorigenic activity paralleled by increased miR-181a expression. This regulatory pathway may explain an increased sensitivity to apoptosis-inducing chemotherapy in subsets of AML patients. Altogether, our data provide a potential explanation for the improved clinical outcomes observed in CEBPA-mutated CN-AML patients, and suggest that lenalidomide treatment enhancing the C/EBPα-p30 protein levels and in turn miR-181a may sensitize AML blasts to chemotherapy.

Purpose To evaluate the prognostic significance of the international European LeukemiaNet (ELN) guidelines for reporting genetic alterations in acute myeloid leukemia (AML). Patients and Methods We analyzed 1,550 adults with primary AML, treated on Cancer and Leukemia Group B first-line trials, who had pretreatment cytogenetics and, for cytogenetically normal patients, mutational status of NPM1, CEBPA, and FLT3 available. We compared complete remission (CR) rates, disease-free survival (DFS), and overall survival (OS) among patients classified into the four ELN genetic groups (favorable, intermediate-I, intermediate-II, adverse) separately for 818 younger (age < 60 years) and 732 older (age ≥ 60 years) patients. Results The percentages of younger versus older patients in the favorable (41% v 20%; P < .001), intermediate-II (19% v 30%; P < .001), and adverse (22% v 31%; P < .001) genetic groups differed. The favorable group had the best and the adverse group the worst CR rates, DFS, and OS in both age groups. Both intermediate groups had significantly worse outcomes than the favorable but better than the adverse group. Intermediate-I and intermediate-II groups in older patients had similar outcomes, whereas the intermediate-II group in younger patients had better OS but not better CR rates or DFS than the intermediate-I group. The prognostic significance of ELN classification was confirmed by multivariable analyses. For each ELN group, older patients had worse outcomes than younger patients. Conclusion The ELN classification clearly separates the genetic groups by outcome, supporting its use for risk stratification in clinical trials. Because they have different proportions of genetic alterations and outcomes, younger and older patients should be reported separately when using the ELN classification.

Abstract High BAALC expression levels are associated with poor outcome in cytogenetically normal acute myeloid leukemia (CN-AML) patients. Recently, miR-3151 was discovered in intron 1 of BAALC. To evaluate the prognostic significance of miR-3151 expression levels and to gain insight into the biologic and prognostic interplay between miR-3151 and its host, miR-3151 and BAALC expression were measured in pretreatment blood of 179 CN-AML patients. Gene-expression profiling and miRNA-expression profiling were performed using microarrays. High miR-3151 expression was associated with shorter disease-free and overall survival, whereas high BAALC expression predicted failure of complete remission and shorter overall survival. Patients exhibiting high expression of both miR-3151 and BAALC had worse outcome than patients expressing low levels of either gene or both genes. In gene-expression profiling, high miR-3151 expressers showed down-regulation of genes involved in transcriptional regulation, posttranslational modification, and cancer pathways. Two genes, FBXL20 and USP40, were validated as direct miR-3151 targets. The results of the present study show that high expression of miR-3151 is an independent prognosticator for poor outcome in CN-AML and affects different outcome end points than its host gene, BAALC. The combination of both markers identified a patient subset with the poorest outcome. This interplay between an intronic miR and its host may have important biologic implications.