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Abstract INTRODUCTION: Among patients (pts) with chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL), the indications for liver biopsy are not known. Additionally, the histopathologic findings of CLL infiltration in the liver along with its clinical implications have not been thoroughly described in the literature. METHODS: We identified all pts with a diagnosis of CLL/SLL from the CLL Clinical Database at Mayo Clinic, Rochester, MN who underwent a liver biopsy. We also cross referenced the Mayo Clinic Hematopathology Database for all pts who underwent a liver biopsy. The indications for biopsy, description of the pathologic findings in the liver biopsy, CLL therapy and outcomes were abstracted from the clinical records. Retrospective pathology review was performed on cases with CLL involvement in which slides were available for review. RESULTS: Fifty-two CLL/SLL pts who underwent a liver biopsy were identified. The indications for liver biopsy were as follows: liver lesion identified on radiographic imaging in 21 (41%) pts, abnormal liver function tests (LFTs) in 17 (33%) pts, hepatosplenomegaly in 11 (21%) pts, and unknown in 3 (6%) pts. Among all 52 pts, there was concern for Richter transformation at time of biopsy in 7 (13%) pts. Types of biopsy were as follows: percutaneous in 20 (39%) pts, intraoperative in 17 (33%) pts, transjugular in 3 (6%) pts, and unknown in 12 (23%) pts. CLL/SLL involvement was identified in 38/52 (73%) pts undergoing liver biopsy. Among these, the diagnosis of CLL/SLL was made on liver biopsy in 8 pts, and 7 pts had additional findings on their liver biopsy including metastatic colon cancer (n=3), hemochromatosis (n=2), steatohepatitis (n=1), and cirrhosis (n=1). Liver biopsy revealed Richter transformation in 4 (8%) pts (3 pts with diffuse large B cell lymphoma (DLBCL) and 1 patient with Hodgkin lymphoma), other malignancy in the absence of CLL in 7 (15%) pts (2 metastatic colorectal, 2 metastatic esophageal, 1 hepatocellular carcinoma, 1 metastatic lung, and 1 neuroendocrine), and 1 patient with steatohepatitis. Two (4%) pts had normal findings on liver biopsy. Among the 38 pts with liver involvement by CLL, 27 had slides available for retrospective pathology review. CLL involvement ranged from 2-100% of the liver parenchyma. Seven pts (26%) underwent excisional biopsies or resections and 20 (74%) underwent core biopsies. The portal tracts were the most common region of the liver involved (22/26 pts, 85%). Of these, 8/22 (36%) pts had extension into the lobules or sinusoids, as well. Of the 4 cases without portal involvement, 2 showed extensive involvement such that it effaced the liver parenchyma in the region of involvement. One patient (4%) had a predominantly sinusoidal involvement. One patient (4%) showed small nodular infiltrates that were difficult to localize due to their size. Proliferation centers were noted in only 3 pts (11%). Most pts (29/38; 76%) whose liver biopsy demonstrated involvement by CLL did not receive immediate CLL-specific treatment. Nine of the 38 pts (24%) with CLL involvement on liver biopsy received therapy (Table): purine analog based therapy (n=4), rituximab and steroids (n=2), steroids only (n=1), alkylator and rituximab (n=1), and ibrutinib (n=1). Pts with extensive involvement of the liver by CLL were more likely to receive purine nucleoside analog based therapy compared to pts with portal infiltration by CLL (2/2 pts [100%] vs. 1/6 pts [17%]). The remaining pts were offered no therapy due to incidental finding of CLL in the liver biopsy (n=11), chemotherapy for other cancer (n=5), palliative care (n=3), or unknown (n=10). Pts with Richter's transformation received R-CHOP (n=2) and CHOP (n=1) for DLBCL, and ABVD (n=1) for Hodgkin lymphoma. Pts with other cancers without CLL received appropriate therapy for their underlying malignancy. CONCLUSION: Abnormal LFTs and radiographic abnormalities were the most common indications for a biopsy in this large cohort of CLL pts. Infiltration of the portal tracts by CLL/SLL was the most common histopathological finding. Proliferation centers were not commonly seen, which may make the diagnosis challenging for the pathologist if there is not a prior history of CLL/SLL. The mere presence of CLL/SLL infiltration did not mandate treatment and many pts were able to continue observation. Table Table. Disclosures Ding: Merck: Research Funding. Kenderian:Novartis: Patents & Royalties, Research Funding. Shanafelt:GlaxoSmithkKine: Research Funding; Celgene: Research Funding; Cephalon: Research Funding; Genentech: Research Funding; Janssen: Research Funding; Pharmacyclics: Research Funding; Hospira: Research Funding. Parikh:Pharmacyclics: Honoraria, Research Funding.

Abstract Background: Individuals with clinically ascertained monoclonal B-cell lymphocytosis (c-MBL) having the phenotype of the chronic lymphocytic leukemia (CLL) have a 1-4% per year risk of progression to CLL requiring therapy. The risk factors for progression and the outcomes of individuals with c-MBL are not well defined. Methods: Using the Mayo Clinic CLL Database, we identified individuals with c-MBL (absolute B-cell count of <5x109/L, in the absence of symptoms, organomegaly, splenomegaly and cytopenias) who were seen at Mayo Clinic, Rochester, MN between 01/1995 - 5/2016. Patients in whom an absolute B-cell count was not available were included in the analysis if the absolute lymphocyte count was <5x109/L. Baseline clinical characteristics and prognostic test results (including IGHV mutation status, genetic abnormalities detected by FISH, and expression of ZAP-70, CD38 and CD49d) were recorded. Time to first therapy (TFT) was analyzed using cumulative incidence methods accounting for competing risk of death. Multivariable Cox proportional hazards regression analysis was used to identify factors that predicted TFT. Because of missing data for some prognostic parameters, multiple models were run, introducing one novel prognostic factor at a time to the base model (which consisted of age and sex). Overall survival (OS) of these individuals was compared to age- and sex-matched population of the state of Minnesota. Results: Eight hundred and fifty-one individuals with c-MBL were identified and included in this analysis. Median age was 69 years (range, 38-95 years), and 527 (62%) were males. The median absolute B-cell count at the time of diagnosis was 2.6 x 109/L (range, 0.1-5.0 x 109/L). The median serum beta-2 microglobulin (β2M) was 2.2 mg/dL (range, 1.0 - 21.5 mg/dL). One hundred and nine (30%) individuals had unmutated IGHV genes, and 38 (7%) had high-risk FISH (defined as either del17p13 or del11q23). The CD38 (≥30%), ZAP-70 (≥20%), and CD49d (≥30%) status was positive in 19%, 23% and 34% individuals, respectively. After a median follow-up of 6.8 years, 99 individuals required therapy for progressive disease (at a rate of 2.1% per year, Figure 1). On multivariable analysis, the following factors were associated with a higher risk of progression to CLL requiring therapy: a) unmutated IGHV status (hazard ratio [HR]:3.8, 95%CI 2.1 - 7.0, p<0.0001); b) positive CD49d status (HR: 3.1, 95%CI 1.6 - 5.9, p=0.0006); and c) positive CD38 status (HR: 2.8, 95% CI 1.7 - 4.8, p<0.0001). Although the HR for high-risk FISH was 2.0 (95% CI 0.9 - 4.4), it was not significantly associated with TFT (p=0.11), likely due to small sample size. Age, sex, serum β2M, and ZAP-70 expression were not predictive of TFT. Among these individuals with B-cell counts <5x109/L, further stratification of the absolute B-cell count at diagnosis showed no association with TFT (Figure 2). The median OS of individuals with c-MBL was 11.8 years. Although the OS among individuals with c-MBL and the age- and sex-matched general population of Minnesota appeared similar for the first 10 years of follow-up, OS was significantly shorter in the c-MBL group during the full follow-up interval (p=0.004, Figure 3). Conclusion: In this large cohort of individuals with clinically ascertained MBL, the risk of progression to CLL requiring therapy was 2.1% per year. Biological characteristics of the B-cell clone including IGHV mutation status, and CD49d and CD38 status predicted time to first CLL therapy. On extended follow-up, the OS of individuals with c-MBL was significantly shorter relative to age- and sex-matched general population. These findings have important implications for counselling individuals with clinically ascertained MBL. Disclosures Parikh: Pharmacyclics: Honoraria, Research Funding. Ding:Merck: Research Funding. Kenderian:Novartis: Patents & Royalties, Research Funding. Shanafelt:Pharmacyclics: Research Funding; GlaxoSmithkKine: Research Funding; Janssen: Research Funding; Genentech: Research Funding; Celgene: Research Funding; Cephalon: Research Funding; Hospira: Research Funding.

Abstract Background : Cytogenetic abnormalities in PMF have been broadly classified into “favorable” and “unfavorable” risk categories. The latter include +8, -7/7q-, i(17q), inv(3), -5/5q-, 12p-, 11q rearrangements and complex karyotype (Leukemia. 2011;25:82). In a more recent study, we had demonstrated an even worse prognosis for patients with monosomal karyotype (MK), inv(3) and i(17q) abnormalities (Blood. 2011;118:4595). In the current study, we revisited the topic using a larger database. Methods: PMF diagnosis was according to World Health Organization criteria (Blood. 2009;114:937). Cytogenetic analysis and reporting was done according to the International System for Human Cytogenetic Nomenclature (Cytogenetic and genome research. 2013. Prepublished on 2013/07/03 as DOI 10.1159/000353118). Assignment to “normal” karyotype required a minimum of 10 metaphases analyzed. A complex karyotype was defined as the presence of 3 or more distinct structural or numeric abnormalities. MK was defined as 2 or more distinct autosomal monosomies or single autosomal monosomy associated with at least one structural abnormality (JCO. 2008;26:4791). Results : A total of 903 patients (median age 65 years; range 19-92; 63% males) met the above stipulations for study eligibility. Dynamic International Prognostic Scoring System (DIPSS)-plus risk distribution (JCO. 2011;29:392) was high in 344 (38%) patients, intermediate-2 in 334 (37%), intermediate-1 in 128 (14%) and low in 97 (11%). 472 patients were annotated for JAK2/CALR/MPL mutations; 276 (58%) harbored JAK2, 117 (25%) CALR and 33 (7%) MPL mutations. Abnormal karyotype was documented in 437 (48%) patients and included sole abnormalities of 20q- (n=71; 16%), 13q- (n=57; 13%), +8 (n=25; 5%), -7/7q- (n=17; 4%) and +9 (n=16; 3%). 22 (5%) patients displayed MK and 31 (7%) complex karyotype without MK. At a median follow-up time of 3 years, 634 (70%) deaths and 65 blast transformations (BT; 7%) were recorded. A step-wise survival analysis, using “normal karyotype” and “MK/inv(3)/i(17q)” as comparators for “low” and “very high risk” categories, respectively, resulted in four distinct cytogenetic risk designations: very high (MK, inv(3), i(17q), -7/7q-, 11q or 12p abnormalities; n=67), high (complex without MK, two abnormalities not included in very high risk category, 5q-, +8, other autosomal trisomies except +9, and other sole abnormalities not included in other risk categories; n=164), intermediate (sole abnormalities of 20q-, 1q duplication or any other translocation, and -Y or other sex chromosome abnormality; n=133) and low (normal or sole abnormalities of 13q- or +9; n=539); the corresponding median survivals were 0.9, 2.6, 3.8 and 4.6 years, with respective HR (95% CI) of 4.4 (3.3-5.8), 2.0 (1.6-2.4) and 1.3 (1.03-1.6). Very high (HR 6.1, 95% CI 2.9-13.2) and high (HR 2.2, 95% CI 1.1-4.1) risk categories were also associated with higher risk of BT. There was no significant correlation between the revised cytogenetic risk stratification and JAK2/CALR/MPL mutational categories (p=0.22), but none of the triple-negative or MPL-mutated patients displayed “very high risk” karyotype. The revised cytogenetic model was also effective in risk-stratification of JAK2 or CALR mutated patients, when analyzed separately, and its prognostic relevance for survival was generally independent of JAK2/CALR/MPL mutational status (p<0.01), DIPSS (p<0.01) or DIPSS-plus (p<0.01). Comparison of the currently used “favorable” vs “unfavorable” with the revised cytogenetic risk model showed a significant number of patients with “favorable” karyotype (n=213 of total 753) being re-assigned to high (n=82) or intermediate (n=131) risk categories. Conclusions : The currently used cytogenetic risk stratification in PMF is too broad and underestimates prognosis in a significant number of patients with “favorable” karyotype. We have developed a revised four-tier risk model that is independent of conventional risk models and JAK2/CALR/MPL mutational status and is expected to facilitate the development of genetics-based prognostic scoring systems in PMF. Disclosures No relevant conflicts of interest to declare.

Abstract Background: 'Myelodysplastic syndrome (MDS) with isolated del(5q),' as defined by the World Health Organization (WHO) criteria (SwederlowSH, et al, 2008) is a unique pathological entity with favorable outcomes. The 2016 revision to the classification expands this entity to include cases that have an additional cytogenetic abnormality, with the exception of monosomy 7 or del(7q) (Arber DA, et al, Blood 2016). The objective of our study was to evaluate the prognostic impact of an additional cytogenetic abnormality, other than monosomy 7 or del(7q), in patients with 'MDS with isolated del(5q)'. Methods: After due IRB approval, the Mayo Clinic MDS database (n=1067) was utilized for this study. All patients had bone marrow (BM) biopsies and cytogenetic studies performed at diagnosis. The International Society for Cytogenetic Nomenclature guidelines were used for cytogenetic nomenclature, while the 2008 and 2016 WHO criteria were used for morphological diagnosis. Results: Patient Characteristics: 72 patients (7.2%) met the 2016 WHO criteria for 'MDS with isolated del(5q)' of which 60% were female and median age was 74 years (28-90). In 61 (85%) cases del(5q) was the only cytogenetic abnormality, while in 11 (15%), del(5q) was present with an 'additional cytogenetic abnormality' (ACA). One additional case within the database had del(5q) accompanied with monosomy 7, which was not included in the analysis. Risk stratification by IPSS-R was as follows; 24 (29%) 'very low', 44 (64%) 'low' and 4 (6%) 'Intermediate' risk, with no patient classified as 'high' or 'very high' risk. At a median follow up of 43 months, 55 (76%) deaths and 5 (7%) leukemic transformations were documented. del(5q) versus del(5q) with an additional cytogenetic abnormality- phenotypic correlates: In the 'del(5q) with ACA' group, the additional abnormalities included trisomy 8 (n=4), del(20q) (n=3), der(9;18) (n=1), inv(3)(p25,q21)(n=1), -Y (n=1), and i(Xp) (n=1) (Table 1). There was no significant difference between the 'del(5q)' and 'del(5q) with ACA' groups in terms of age, gender, hemoglobin, platelet count, white cell count, absolute neutrophil count, bone marrow blast percentage or transfusion requirement. A greater proportion of the 'del(5q) with ACA' group (27%) had IPSS-R risk in the 'intermediate' category compared to the 'del(5q)' group (2%) (p=0.01). 18 of 42 cases diagnosed after 2004 (43%) were treated with lenalidomide, with no difference in the proportions treated between the two groups (p=1.00). del(5q) versus del(5q) with an additional cytogenetic abnormality- impact on overall survival (OS) and leukemia-free survival (LFS): The median survival of the cohort was 54 months. Survival was not significantly different between the 'del(5q)' group (median 55 months) and the 'del(5q) with ACA' group (median 38 months) (p=.75, Figure 1). This finding was consistent when analysis was restricted to patients in both groups treated with lenalidomide (p=0.29). The incidence of leukemic transformation in the del(5q) group was 5%, compared with 18% for the 'del(5q) with ACA' group (p=0.16), however there was no significant difference in LFS between the two groups (p=0.57). Conclusion : In our cohort of primary MDS patients meeting the 2016 WHO definition of 'MDS with isolated del(5q)', we confirm no significant survival difference between cases with del(5q) as the sole cytogenetic abnormality versus cases where del(5q) was accompanied by an additional cytogenetic abnormality. Table 1 Additional Cytogenetic Abnormalities with del(5q): Table 1. Additional Cytogenetic Abnormalities with del(5q): Figure 1 del(5q) vs del(5q) with an additional abnormality (ACA): Overall Survival Figure 1. del(5q) vs del(5q) with an additional abnormality (ACA): Overall Survival Disclosures Al-Kali: Onconova Therapeutics, Inc.: Research Funding; Celgene: Research Funding.

Abstract Background We have previously shown an independent adverse prognostic effect of lymphopenia (absolute lymphocyte count <1.2 x 10(9)/L) for survival in MDS (Jacobs et al. Am J Hematol 2010;85:160) whereas others have suggested a similar value from lymphocyte-to-monocyte ratio (LMR); patients with LMR ≥5 experienced shorter survival with median 67 vs. 126 months (Mushtaq et al. JCO May 20 Supp. 2016:7062). Whether or not "monocytopenia" also carries a prognostic value in MDS is currently unknown and was the main objective for the current study, which also addresses the prognostic value of LMR. Methods We retrospectively recruited 889 consecutive patients with primary MDS who were untreated at the time of referral to our institution and in whom absolute monocyte count (AMC) and absolute lymphocyte count (ALC) at time of referral were documented. The diagnosis of MDS and leukemic transformation (LT) was made according to WHO criteria (Blood. 2009;114:937). Complete follow-up information was updated in January 2015. For the purposes of the current study, monocytopenia was defined as AMC below the lower limit of the institutional normal range, which was 0.3 to 0.9 x 10(9)/L. Comparisons of survival and other clinical parameters were performed between i) patients with and without monocytopenia and ii) patients with and without LMR ≥5. Conventional methods were used for statistical analysis. Results Patient characteristics: Median (range) values for the 889 study patients (69% males) included: age 72 (18-98), hemoglobin 9.6 g/dL (5.4-15.7), leukocyte count 3.4 x 10(9)/L (0.4-35), platelet count 106 x 10(9)/L (2-1804), circulating blasts 0% (0-18), bone marrow blasts 3% (0-19) and absolute lymphocyte count (ALC) 1.2 x 10(9)/L (.02-8.9). Transfusion need was documented in 33% of patients and abnormal cytogenetics in 49%. Risk stratification by the revised international prognostic scoring system (IPSS-R) was very high in 11%, high in 16%, intermediate in 21%, low in 36% and very low in 16%. The median (range) AMC for the entire study population of 889 patients was 0.22 x 10(9)/L (0.0-1.8).The number of patients with subnormal AMC was 539 (61%). After a median follow-up of 27 months, 712 (80%) deaths and 116 (13%) leukemic transformations were documented. Comparison of patients stratified by absolute monocyte count and LMR Compared to patients with AMC >0.3 x 10(9)/L, MDS patients with monocytopenia displayed younger age (p<0.0001), lower hemoglobin (p=0.005), higher red blood cell transfusion need (p=0.03), lower leukocyte count (p<0.0001), lower platelet count (p<0.0001), lower absolute neutrophil count (p<0.0001), higher circulating (p=0.03) and bone marrow (p<0.0001) blasts, higher incidence of abnormal karyotype (p=0.03), and higher risk distribution in terms of both IPSS-R (p<0.0001) and cytogenetic risk stratification by IPSS-R (p=0.03). In univariate analysis, lower AMC was associated with inferior survival (p=0.002); significance was even more apparent when comparing patients with and without monocytopenia (p=0.0003; HR 1.3, 95% CI 1.1-1.5). Similarly, there was significant association between LMR and survival (p<0.0001) with patients with LMR ≥5 experiencing inferior survival (p=0.03; HR 1.2; 95% CI 1.02-1.4). In multivariable analysis, the adverse effect of monocytopenia was shown to be independent of age (p<0.0001), gender (p=0.0001), anemia (Hemoglobin <10 g/dL; p=0.002), thrombocytopenia (platelets <100 x 10(9)/L; p=0.01), neutropenia (absolute neutrophil count <0.8 x 10 (9)/L; p=0.005), subnormal ALC (p=0.0008), circulating blast percentage (p=0.002), cytogenetic risk stratification by IPSS-R (p=0.006) and LMR (p=0.02) or LMR ≥5 (p=0.002); however, significance was lost when risk stratification by IPSS-R was added to the multivariable analysis (p=0.7). In regards to LMR, it retained its significance (p=0.009) during multivariable analysis that included monocytopenia or subnormal ALC, as covariates; however, significance was lost in the context of IPSS-R (p=0.24 for LMR and 0.8 for LMR ≥5) Conclusions Monocytopenia in MDS clusters with adverse disease features and both monocytopenia and higher LMR were associated with poor survival. Despite the display of prognostic independence from each other and other risk factors considered individually, the survival impact of neither monocytopenia nor LMR was found to be independent of IPSS-R. Disclosures Al-Kali: Novartis: Research Funding; Celgene: Research Funding.

Abstract Background A recent study from the International Working Group on Myeloproliferative Neoplasms Research and Treatment (IWG-MRT) identified prior arterial events and hypertension as risk factors for subsequent arterial thrombosis and prior venous events and age 65 years or older as risk factors for venous thrombosis in polycythemia vera (PV) (Blood 2014;124:3021). In the current single center study, we sought to validate the aforementioned findings from the IWG-MRT and look into further details regarding arterial versus venous thrombosis in PV. Methods Study patients were selected from our institutional database of myeloproliferative neoplasms (MPN) and fulfilled the 2008 World Health Organization (WHO) criteria for the diagnosis of PV (Blood. 2009;114:937). Screening for the two most frequent mutations other than JAK2 (TET2 and ASXL1) were performed according to conventional methods (Leukemia. 2014;28:2206). Statistical analyses considered clinical and laboratory parameters obtained at time of diagnosis. Results Patient characteristics: Analysis was conducted on 587 patients (median age 60 years; 48% males). ASXL1 and TET2 mutational status was available in 133 patients. Among informative cases, 31% had palpable splenomegaly, 34% microcirculatory symptoms, 30% pruritus, 8% erythromelalgia, 42% hypertension, 9% diabetes and 11% were active tobacco users. TET2 and ASXL1 mutations were documented in 18% and 11%, respectively. During follow-up, 224 (38%) patients died and median follow-up for living patients was 109 months. Median survival was 16 years and leukemic or fibrotic transformations were documented in 4% and 14%, respectively. Thrombotic events: A total of 235 (40%) patients experienced at least one thrombotic event before or after diagnosis and included 153 (26%) arterial and 104 (18%) venous events. Thrombotic events were recorded before or at time of diagnosis in 146 (25%) patients and included 97 (17%) arterial and 55 (9%) venous events. Thrombotic events after diagnosis were recorded in 128 (22%) patients and included 82 (14%) arterial and 57 (10%) venous events. Associations for arterial, venous or all thrombotic events occurring at any time before or after time of diagnosis: The occurrence of any thrombotic event before or after diagnosis correlated with active tobacco use (p=0.04), diabetes history (p=0.03), hyperlipidemia (p=0.04) and major hemorrhage (p=0.03). The occurrence of any arterial event before or after diagnosis correlated with advanced age (p=0.006), diabetes history (p=0.005), hypertension history (p=0.004) and hyperlipidemia (p<0.0001). The occurrence of any venous event before or after diagnosis correlated with female sex (p=0.008), younger age (p<0.0001), lower platelet count (p=0.0014) and palpable splenomegaly (p=0.006). TET2 or ASXL1 mutations did not correlate with overall, arterial or venous thrombosis. Risk factors for arterial versus venous events after time of diagnosis: In univariate/multivariable analysis, thrombosis-free survival (TFS) was adversely affected by prior vascular events (p=0.002/0.03 multivariable) and increased leukocyte count (p=0.03/0.03); arterial thrombosis-free survival was adversely affected by prior arterial events (p<0.0001/P<0.0001), hyperlipidemia (p=0.001/0.03), hypertension (p=0.02/NS) and advanced age (p=0.02/NS); venous thrombosis-free survival was adversely affected by prior venous events (p=0.04/0.05), increased leukocyte count (p=0.0009/0.002), and younger age (p=0.02/NS). In addition, major hemorrhage at diagnosis was associated subsequent venous thrombosis in both univariate and multivariable analysis. TET2 or ASXL1 mutations did not affect the risk of overall, arterial or venous thrombosis. Conclusions In contemporarily managed patients with PV, prior vascular events predict future events for both arterial and venous thrombosis; additional risk factors included hyperlipidemia for arterial and increased leukocyte count for venous thrombosis. The current study also identifies association of arterial thrombosis in general with older age and history of hypertension, diabetes or hyperlipidemia whereas venous thrombosis was associated with younger age, female sex and palpable splenomegaly. Additional findings included association of major hemorrhage with thrombosis and higher platelet count with lower risk of venous thrombosis. Disclosures No relevant conflicts of interest to declare.

Abstract Background The International Working Group for Myeloproliferative Neoplasms (MPN) Research and Treatment (IWG-MRT) previously published on 1104 patients with "essential thrombocythemia (ET)" and identified 180 (16%) misdiagnosed cases with early/prefibrotic primary myelofibrosis (PMF); the latter diagnosis was associated with inferior overall (OS), leukemia-free (LFS) and myelofibrosis-free (MFFS) survival (J Clin Oncol. 2011; 29:3179). Among the 891 patients with "true" World Health Organization (WHO)-defined ET, risk factors for OS included age ≥60 years, leukocyte count ≥11 x 10(9)/L and history of thrombosis (Blood2012120:1197). In the current study, we explored the possibility that increased serum lactate dehydrogenase (LDH) level or mild grade-1 reticulin fibrosis might identify occult cases of early/prefibrotic PMF in otherwise WHO-defined ET and contribute to disease prognostication. Methods Study patients were selected from the Mayo Clinic institutional database of MPN based on their meeting the 2008 WHO criteria for diagnosis of ET (Blood. 2009;114:937). The degree of bone marrow (BM) reticulin fibrosis was based on "real life" BM reports from Mayo Clinic hematopathologists and often in accordance with the European consensus scoring system (Haematologica 2005;90:1128). Serum LDH levels were obtained at time of diagnosis or within 12 months of diagnosis, in the absence of any treatment. Information on the two most frequent non-driver mutations seen in ET (i.e. TET2 and ASXL1) was available in a subset of the patients (Blood 2015 126:354). Statistical analyses considered clinical and laboratory parameters obtained at time of diagnosis Results Patient characteristics: 183 patients (57% females) were evaluable for BM reticulin grading; median (range) levels were for age 59 years (15-88), hemoglobin 14 g/dL (9.1-17.1), platelets 812 x 10(9)/L (454-3300) and leukocyte count 8.5 x 10(9)/L (3.1-31.5). Palpable splenomegaly was reported in 27 (15%) patients and 12% displayed leukoerythroblastosis (LES). Driver mutational status was JAK2 in 72%, CALR 17%, MPL 2% and triple-negative in 9%. Thrombosis history at diagnosis was obtained from 13% of the patients and 12% experienced the same post diagnosis. Risk stratification according to the International Prognostic Scoring System for ET (IPSET) was 19% high, 43% intermediate and 38% low (Blood2012120:1197). BM reticulin fibrosis was graded "0" in 113 (62%) patients and "1" in 70 (38%). Serum LDH information was available in 110 patients (median194 U/L; range 135-669) and was increased in 31 (28%) patients. Mutational status for TET2 and ASXL1was available in 76 patients with mutational frequencies of 8% each. Clinical and laboratory correlates for mild reticulin fibrosis and serum LDH: We found no significant correlation between mild reticulin fibrosis (grade-1) and a number of clinical parameters, including age, sex, hemoglobin level, leukocyte count, platelet count, driver mutational status, LES, presence of palpable splenomegaly, thrombosis history or serum LDH (p=0.36). In contrast, increased serum LDH was associated with increased leukocyte count (p=0.002), increased platelet count (p<0.001), presence of palpable splenomegaly (p=0.03) and higher IPSET score (p=0.002); there were no significant correlations with age, sex, hemoglobin level, LES, thrombosis history, driver mutational status or TET2/ASXL1mutations. Survival analysis: After a median follow-up of 91 months, 42 (23%) deaths, 2 (1%) leukemic transformations, 7 (4%) fibrotic progressions and 22 (12%) thrombotic events were documented. In univariate analysis, risk factors for OS included age ≥60 years (p=0.002; HR 10.2, 95% CI 2.3-44.6), male sex (p=0.02; HR 3.2, 95% CI 1.2-8.2), leukocyte count ≥15 x 10(9)/L (p=0.007; HR 4.7, 95% CI 1.5-14.6), and increased serum LDH (p=0.004; HR 3.7, 95% CI 1.5-9.1), but not BM reticulin fibrosis (p=0.17). In multivariable analysis, age, sex and LDH remained significant; serum LDH also remained significant for OS, in the context of IPSET, whereas it did not appear to influence thrombosis-free survival (p=0.58), LFS (p=0.84) or MFFS (p=0.34). Conclusions The current study suggests that serum LDH might supersede leukocyte count as an independent risk factor for overall survival in ET; in contrast, mild reticulin fibrosis was irrelevant in terms of both prognostic value and disease phenotype. Disclosures No relevant conflicts of interest to declare.

Abstract Background In polycythemia vera (PV), abnormal karyotype at diagnosis has been reported in 10% to 20% of patients and some studies have suggested an association with inferior survival (Leukemia2013;27:1874) . In the current study, we examined the prognostic contribution of abnormal karyotype, in general, and specific abnormalities, in particular, in newly diagnosed PV. Methods Study patients were selected from our institutional database of myeloproliferative neoplasms (MPN) and fulfilled the 2008 World Health Organization (WHO) criteria for diagnosis of PV (Blood. 2009;114:937). Cytogenetic analysis and reporting was done according to the International System for Human Cytogenetic Nomenclature (Cytogenetic and Genome Research2013;141:1-6). Assignment as "unfavorable karyotype" was according to criteria established for PMF: favorable = normal + favorable abnormalities; unfavorable = unfavorable abnormalities (Leukemia. 2011;25:82). Screening for the two most frequent mutations in PV, other than JAK2 (i.e. TET2 and ASXL1), were performed according to conventional methods (Leukemia. 2014;28:2206). Statistical analyses considered clinical and laboratory parameters obtained at time of diagnosis. Results Patient characteristics: Median (range) values for the 239 study patients (53% females) included: age 62 (17-94), leukocyte count 11.7 x 10(9)/L (4.3-59.3) and platelet count 479 x 10(9)/L (37-2747). Palpable splenomegaly was present in 26% of the patients, pruritus in 27%, erythromelalgia in in 8%, hypertension in 47%, diabetes in 10% and hyperlipidemia in 28%. Thrombosis history at diagnosis was documented in 33% of the patients and 20% experienced the same after diagnosis. 73% of the patients were "high risk" by conventional risk stratification. Mutation screening for TET2 and ASXL1 was performed in 80 patients and mutational frequencies were 19% and 11% respectively. All study patients provided cytogenetic information, which was abnormal in 46 (19%) patients. The most frequent abnormalities were isolated +9 (n=11; 24% of abnormal karyotype and considered favorable), isolated del(20q) (n=8; 17% of abnormal karyotype and considered favorable), isolated loss of Y chromosome (n=7; 15% of abnormal karyotype and considered favorable) and isolated +8 (n=5; 11% of abnormal karyotype and considered unfavorable). A total of 9 (20% of abnormal karyotype) patients displayed unfavorable karyotype that included +8 in 7 patients, del(11q) in one patient and +20 in one patient. After a median follow-up of 83 months, 70 (29%) deaths, 48 (20%) thrombotic events, 20 (8%) fibrotic progressions and 7 (3%) leukemic transformations were documented. Comparison of patients with and without cytogenetic abnormalities Patients with abnormal cytogenetics were older (p=0.048), displayed lower platelet count (p=0.005) and were more likely to be high risk (p=0.02); there was no significant correlation with TET2 or ASXL1 mutation. In univariate analysis, patients with abnormal cytogenetics displayed inferior leukemia-free (p=0.007; HR 10.6, 95% CI 1.9-58.7), myelofibrosis-free (p<0.0001; HR 7.7, 95% CI 3.1-19.3) and overall (p=0.13; HR 1.6, 95% CI 0.9-2.8) survival. Furthermore, the difference in overall survival became significant when cytogenetic abnormalities were classified into unfavorable (p=0.006) and favorable (p=0.6) categories. On the other hand, inferior leukemia-free and myelofibrosis-free survival was noted in both patients with favorable and unfavorable cytogenetic abnormalities, when compared to normal karyotype. During multivariable analysis that included age and leukocytosis (≥15 x 10 (9)/L) as covariates, the adverse effect of abnormal cytogenetics on leukemia-free (p=0.009) or myelofibrosis-free (p<0.0001) survival and that of unfavorable karyotype on overall (p=0.05) survival were shown to be independent. Finally, patients with abnormal cytogenetics were less likely to experience thrombosis after diagnosis (p=0.04; HR 0.3, 95% CI 0.09-0.97), an effect that was independent of both age and thrombosis history. Conclusions Cytogenetic abnormalities in PV confer an independent adverse prognostic effect on overall, leukemia-free and myelofibrosis-free survival, but not thrombosis-free survival; the adverse effect on leukemia-free and myelofibrosis-free survival was seen with both favorable and unfavorable cytogenetic abnormalities. Disclosures No relevant conflicts of interest to declare.

Abstract Background The International Working Group for Myeloproliferative Neoplasms (MPN) Research and Treatment (IWG-MRT) has previously identified older age, leukocytosis, venous thrombosis and abnormal karyotype as risk factors for overall survival (OS) in polycythemia vera (PV), and older age, abnormal karyotype and leukocytes ≥15 × 109/l as risk factors for leukemia-free survival (LFS) (Leukemia2013;27:1874). Serum lactate dehydrogenase (LDH) is a surrogate quantitative measure of cell turnover and tumor burden. We hypothesized that, compared to leukocyte count, serum LDH might be a biologically more accurate indicator of tumor aggression and sought to examine its potential utility as a prognostic biomarker in PV. Methods Study patients were selected from our institutional database of MPN based on their meeting the 2008 or 2016 World Health Organization criteria for diagnosis of PV (Blood. 2009;114:937; Blood 2016 127:2391) and availability of serum LDH level, obtained within six months of diagnosis. Information on karyotype and targeted next-generation sequencing was available in a subset of the patients (Blood 2015 126:354). Statistical analyses considered clinical and laboratory parameters obtained at time of diagnosis. Age and leukocyte count prognostic categories were based on previously published IWG-MRT study (Leukemia2013;27:1874). Results Patient characteristics: A total of 216 patients (50% females) met the above-outlined criteria: median (10th-90th percentile) levels were for age 63 years (38-81), hemoglobin 18 g/dL (16.6-20.7), platelets 467 x 10(9)/L (237-833), leukocyte count 11.7 x 10(9)/L (7.2-20.3) and spleen size 0 cm (0-2). Pruritus was documented in 28%, microcirculatory symptoms in 31%, erythromelalgia in 6%, hypertension in 45%, diabetes in 7%, active tobacco use in 13%, hyperlipidemia in 25%, palpable spleen in 26% and abnormal karyotype in 15% of informative cases. Grading for bone marrow reticulin fibrosis was documented for 144 patients: 50% grade "0", 42% grade "1", 7% grade "2" and 1 grade "3". Thrombosis history at diagnosis was documented in 26% of patients and occurred after diagnosis in 19%. Mutation analysis was available in 72 patients and revealed TET2 mutations in 18 (25%), ASXL1 in 5 (7%), SRSF2 in 2 (3%) and IDH2 in one (1.4%). Serum LDH levels and correlates: Median serum LDH level was 226 U/L (range 71-1008); the upper normal limit (UNL) for Mayo Clinic was 222 U/L. Increased serum LDH was recorded in 110 (51%) patients that included 26 (12%) patients with LDH ≥1.5 x UNL. A significant correlation was demonstrated between increased serum LDH and older age (p=0.007), female sex (p=0.04), leukocytosis (p=0.01), venous thrombosis history (p=0.005) and, interestingly, absence of active tobacco use (p=0.003); no correlation was noted for bone marrow reticulin fibrosis, presence of palpable splenomegaly, abnormal karyotype or ASXL1 mutation. Survival analysis: After a median follow-up of 77 months, 82 (38%) deaths, 8 (3.7%) leukemic transformations, 13 (6%) fibrotic progressions and 41 (19%) thrombotic events were documented. In univariate analysis, the following adversely affected OS: advanced age (P<0.0001), increased LDH as a continuous variable (p=0.0006), LDH ≥1.5 x UNL (p<0.0001), leukocyte count ≥15 x 10(9)/L (p=0.02) and arterial thrombosis history (p=0.001). In multivariable analysis, only age and LDH remained significant; multivariable HR (95% CI) were 5.4 (2.8-10.4) for age ≥67 years, 3.2 (1.8-6.0) for LDH ≥1.5 x UNL and 2.4 (1.2-4.7) for age 57 to 66 years. In the subset of patients with available information on karyotype and non-JAK2 mutations (n=72), advanced age, LDH ≥1.5 x UNL and ASXL1 mutations remained significantly associated with inferior survival. Serum LDH also predicted leukemic transformation (HR 17.8, 95% CI 4.1-78) and fibrotic progression (HR 11.6, 95% CI 25-53.7); in multivariable analysis, only serum LDH ≥1.5 x UNL (HR 22.3, 95% CI 2.1-234.6) and abnormal karyotype (HR 9.5, 95% CI 1.2-74.7) predicted leukemic transformation and only the former predicted fibrotic progression. Conclusions Serum LDH is a simple and inexpensive biomarker that might supersede leukocyte count as an independent predictor of overall, leukemia-free and myelofibrosis-free survival in PV; advanced age and ASXL1 mutations also retained significance for OS and abnormal karyotype for LFS. Disclosures No relevant conflicts of interest to declare.

Abstract Background: Most patients with chronic myelomonocytic leukemia (CMML) are elderly and age >65 years is an adverse prognostic factor (JCO 2013;31:2428). Our objective in the current study was to examine risk factors for survival and treatment outcome in younger patients (age ≤65 years), with emphasis on molecular and cytogenetic markers. Methods: DNA analysis for SRSF2, SF3B1, U2AF1, ASXL1 and SETBP1 mutations was carried out on specimens obtained at time of diagnosis. We used both conventional and revised (see accompanying ASH 2014 abstract) cytogenetic risk models to query their application in the current study population. Treatment data included outcome of allogeneic stem cell transplant (HCT) and treatment with hypomethylating agents (HMA), including azacitidine (AZA) and decitabine (DAC). Results: Survival: 259 patients (median age 59 years, range 18-65; 75% males) with WHO-defined CMML and age≤ 65 years were included in the study: 108 from the French consortium, 81 Mayo Clinic, 47 Moffitt Cancer Center and 23 University of Milan; 217 (84%) patients had CMML-1 and the remainder CMML-2. At a median follow-up of 26 months, 124 (48%) deaths and 79 (31 %) leukemic transformations were documented. Mutational frequencies were 34% (61/178) for ASXL1, 45% (74/165) for SRSF2, and 4% (7/168) for SETBP1. Cytogenetic data was available in 248 of 259 study patients; 56 (23%) patients displayed abnormal karyotype and the revised cytogenetic risk designations included 196 (80%) low, 29 (12%) intermediate, and 23 (9%) high. In univariate analysis, lower hemoglobin (p<0.0001), higher WBC (p=0.005), higher monocyte count (AMC) (P=0.004), lower platelet count (p=0.004), presence of circulating immature myeloid cells (IMC) (p=0.004), presence of circulating blasts (p<0.0001), bone marrow (BM) blasts ≥10% (p=0.005), WHO morphological subtype (p=0.0003), Spanish cytogenetic risk stratification (p=0.0002), revised Mayo cytogenetic risk stratification (p<0.0001), SRSF2 (p=0.03) and ASXL1 (p=0.03) mutational status predicted shortened survival. In multivariable analysis, lower hemoglobin (p<0.0002), presence of circulating blasts (p<0.0001), SRSF2 (p=0.03) and ASXL1mutational status (p=0.04) retained their negative prognostic impact. A similar analysis identified circulating IMC (p<0.0001), presence of circulating blasts (p<0.0001), and BM blast % (p=0.0002) as predictors of blast transformation (BT). Response to hypomethylating agents: Seventy-two (28%) patients received HMA (AZA-46, DAC-26, both-6). In the AZA group, median number of cycles was 5 (range; 1-44), median duration of therapy 5 months (range;1-59) with 4 (6%) receiving DAC on progression and 26 (42%) proceeding with HCT. Over-all response rate (ORR) was 25% (6/24) and included complete response (CR) in 2 (8%) patients, partial response (PR) in 2 (8%) and hematological improvement in 2 (8%). In the DAC group, median number of cycles was 6 (2-25), median duration of therapy 5 months (range;1-49), with 2 (8%) receiving AZA on progression; ORR was 50% (7/14) and included CR in 4 (29%) patients, PR in 1 (7%) and HI in 2 (14%). ASXL1 (p=0.4), SRSF2 (p=0.7) mutational status or karyotype (p=0.5 for Spanish and 0.3 for revised Mayo) did not correlate with response to HMA. Allogeneic stem cell transplant: 50 patients underwent HCT. Conditioning regimen was reported in 41 patients and included myeloablative (MA) in 14 (34%) (median age 51 years, 27-62) and reduced intensity (RIC) in 27 (66%) (median age 48 years, 18-65). Donor source was documented in 40 patients and included matched related in 19 (48%), matched unrelated in 12 (30%), mismatched unrelated in 4, haploidentical in 2 and umbilical cord transplant in one. 27 (63%) patients had chronic GVHD (50% in MA group and 80% in the RIC group). Among 40 evaluable patients, 23 (57%) achieved CR, 8 (21%) relapsed and 8 (21%) died from transplant-related complications. ASXL1 (p=0.9), SRSF2 (p=0.5) mutational status or karyotype (p=0.2 for Spanish and 0.3 for revised Mayo) did not affect transplant outcome. Conclusions: Survival in young CMML patients is poor and even worse in the presence of SRSF2 or ASXL1 mutations, anemia or circulating blasts. Treatment outcome was more impressive with transplant than it was with HMA and neither was influenced by karyotype or ASXL1/SRSF2 mutational status. Disclosures No relevant conflicts of interest to declare.