Abstract: Background: The currently used prognostic systems for myelodysplastic syndromes (MDS) do not consider the prognostic role of monocytopenia, although monocytes may participate in the prognosis of the disease as part of the host immunity. Aim: We studied the prognostic significance of monocytopenia in patients with MDS registered in the Hellenic National MDS registry. Methods: We analyzed clinicopathological data from patients with MDS recorded in a large retrospective national registry. Patients with MDS/MPN were excluded, while patients treated with allogeneic hematopoietic cell transplantation were censored for overall survival (OS) and leukemia-free survival (LFS). IBM SPSS statistics, version 23.0 (IBM Corporation, North Castle, NY, USA) was used for the analysis of the results. Kaplan-Meier survival analysis and Cox regression analysis were performed for LFS and OS. Results: The study comprised 1719 patients with MDS per the 2008 WHO classification for MDS. The main characteristics of the patients are shown in Table 1. At the time of data cut-off, 818 patients were deceased and the median follow-up for the remaining 901 patients was 23.0 months. The median absolute monocyte count (AMC) was 0.30 x 109/L (0.00 - 0.99 x 109/L). Patients with excess blasts (RAEB1/2) tended to have lower AMCs (median 0.19 versus 0.32 for patients without excess blasts, p 〈 0.0001) and lower AMCs were found in higher IPSS-R categories (very low, 0.37 x 109/L; low, 0.30 x 109/L; intermediate, 0.25 x 109/L; high, 0.16 x 109/L; very high, 0.20 x 109/L) while there was a highly significant difference between lower risk (very low and low) and higher risk (intermediate, high, very high) MDS (0.33 x 109/L vs 0.21 x 109/L, p 〈 0.0001). In univariate analysis, patients with AMCs below 0.2 x 109/L had a median OS of 34.0 months vs 63.0 months for patients with higher AMCs (p 〈 0.0001) with a hazard ratio (HR) for death of 1.57 (95% CI 1.37 - 1.81, p 〈 0.0001). In a multivariate Cox regression model including hemoglobin below 10 g/dL, absolute neutrophil count (ANC) below 1.0 x 109/L, and platelet count below 100 x 109/L (all of them being prognostic for OS in univariate analysis), monocytopenia retained its prognostic significance (HR, 1.16; 95% CI, 1.00 - 1.36, p=0.049). There was a positive correlation between the AMC and the ANC (Pearson Correlation 0.393, p 〈 0.0001). Nevertheless, in a model comprising of AMC and ANC, both variables were independently correlated to OS. Moreover, in a model including AMC below 0.2 x 109/L, the cytogenetic risk score per the IPSS-R, the number of cytopenias, and bone marrow blasts (categorized per the IPSS-R), no additional prognostic impact was found for AMC (HR, 1.01; 95% CI, 0.86 - 1.17; p=0.957). After stratification per the IPSS-R categories, low AMC was prognostic for low OS only in patients with low IPSS-R (median OS, 57 months for patients with low AMC vs 75 months for those with high AMC, p=0.039), but there was no additional prognostic impact after multivariate analysis. Moreover, AMC was prognostic for LFS, since patients with low AMCs ( 〈 0.2 x109/L) had a median LFS of 57.0 months, while the median LFS for patients with higher AMCs was not reached (HR, 2.47, 95% CI, 2.01 - 2.47, p 〈 0.0001). In a Cox regression model including the above stated factors (cytopenias, bone marrow blasts, cytogenetic risk, and AMC), AMC retained its prognostic significance for LFS (HR, 1.27; 95% CI, 1.02 - 1.58; p=0.031). In a subgroup of 162 patients treated with hypomethylating agents (HMAs), monocytopenia was not predictive or response to treatment, but low AMC was correlated to a shorter median progression free survival (27.0 months vs not reached for patients with higher AMC, p=0.001). This correlation was not translated into a survival benefit (survival after HMA initiation, 27.0 vs 28.0 months respectively, log rank p=0.213). Conclusions: Based on a large patient cohort, we found that patients with MDS with excess blasts as well as higher risk patients per the IPSS-R have low AMCs. Moreover, we showed that low AMCs are prognostic of lower OS in univariate analysis and of lower LFS in both univariate and multivariate analysis, highlighting a possible pathogenetic role for AMCs in MDS. Further analysis is needed to define the exact prognostic role of AMC in MDS. Disclosures Pappa: Amgen: Research Funding; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene / GenesisPharma: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Honoraria, Research Funding; Abbvie: Research Funding; Novartis: Honoraria, Research Funding, Speakers Bureau; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Kotsianidis:Celgene: Research Funding. Symeonidis:MSD: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; Pfizer: Research Funding; Roche: Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: Research Funding; Tekeda: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding. Vassilakopoulos:Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; WinMedica: Honoraria, Membership on an entity's Board of Directors or advisory committees; Abbvie: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene / GenesisPharma: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees.

Abstract: Introduction: Less than 5% of patients with MDS present with thrombocytopenia as an isolated abnormality (MDS-IT). There have been few systematic studies on MDS-IT and data regarding its course and prognosis are conflicting. Previous studies have defined MDS-IT based on the IPSS thresholds (Hb ≥10 g/dL; ANC ≥1.8×10 9/L; PLT & lt;100×10 9/L). However, these were developed for prognostic, not diagnostic purposes which means that mild anemia and/or neutropenia might be present concomitantly with "isolated" thrombocytopenia. We aimed to investigate the characteristics, overall survival (OS), and leukemia-free survival (LFS) of patients with MDS-IT. Methods: We identified patients who had PLT & lt;150 ×10 9/L, Hb & gt;13 g/dL (men) or & gt;12 g/dL (women), and ANC ≥1.8 ×10 9/L, registered in the Hellenic National Registry of Myelodysplastic and Hypoplastic Syndromes which includes 2792 patients (analysis cut-off date; July 7, 2016). Patients were divided into 4 groups: group 1 had PLT 149-100 ×10 9/L; group 2, 99-50 ×10 9/L; group 3, & lt;50 ×10 9/L; and group 4, & lt;25 ×10 9/L. We also collected data from the Hellenic National ITP Registry which includes 1317 adult patients with ITP. Results: A total of 77 patients (45 men; 32 women) with MDS-IT were identified (2.9% of total MDS cohort). Of these, 28.6% were classified in group 1; 49.4% in group 2; 14.3% in group 3; and 7.8% in group 4. Median PLT count was 87 ×10 9/L (12-139 ×10 9/L), WBC count 4.6 ×10 9/L, and Hb 13.6 g/dL. Bone marrow (BM) blasts ranged from 0-9% (median, 2%). Median follow-up was 51.0 months (41.6-60.4), during which 15 (19.5%) patients died. AML developed in 9 patients (11.7%). Histologically, MDS with multilineage dysplasia (MLD) was seen in 77.6% whereas MDS with excess blasts (EB) and MDS with single lineage dysplasia (SLD) comprised 10.7% and 11.9% of cases, respectively. Most patients (73.5%) had lower-risk MDS on the IPSS-R (i.e. IPSS-R ≤3.5). Of the 59 patients with cytogenetic data, 83.1% had favorable, 13.5% intermediate, and 3.4% poor risk cytogenetics. Most (40) had a normal karyotype followed by isolated del(20q) (6). All patients with del(20q) showed a characteristic set of clinical features: age & gt;60 years, blasts 0-3%, bilineage (erythroid/megakaryocytic) dysplasia, and increased reticulin fibrosis. There were no significant differences between any of the 4 PLT groups regarding age, sex, IPSS-R, cytogenetics, BM blasts, and histology. Median OS was 109 months (95% CI 103-115) and LFS 108 months (101-115). Our results showed no significant difference in OS (P=0.891) and LFS (P=0.871) between the 4 PLT groups. As compared with total MDS cohort, MDS-IT occurred at younger age (64.7 vs. 72.4 years, P & lt;0.001). In a Kaplan-Meier analysis, patients with MDS-IT had markedly longer OS and LFS than patients in the total MDS cohort, even after adjustment for age, sex, IPSS-R, blasts, and PLT (P=0.013 for OS; P=0.017 for LFS) (Figure 1A). There were no differences in the top causes of death: infection was the commonest cause followed by disease progression and cardiovascular disease. Major bleeding comprised 10.3% of deaths in MDS-IT vs. 12.7% in total MDS cohort (P=0.217). In comparing MDS-IT with ITP, the median age at diagnosis was 66.0 years for MDS-IT and 49.0 years for ITP (P & lt;0.001).MDS-IT was uncommon in patients & lt;50 or & gt;80 years. Its incidence reached a peak between the ages of 70-79 years, whereas ITP occurred at a more constant level over time (Figure 1B). Women predominated in ITP and men in MDS-IT (P=0.007). Overall, ITP was associated with more marked thrombocytopenia than MDS-IT (15.0 ×10 9/L vs. 87.0 ×10 9/L) (P & lt;0.001). Median WBC count was higher in ITP (7.6 ×10 9/L vs. 4.6 ×10 9/L; P & lt;0.001). Median Hb was similar in the 2 groups. Patients with ITP had longer OS than MDS-IT (P & lt;0.001). Conclusions: In one of the largest reported series, we conclude that MDS-IT is associated with MDS-MLD, favorable cytogenetics, lower-risk IPSS-R, high survival rate, and a low risk of AML evolution. Our data suggest that the superior prognosis in MDS-IT than general MDS may have intrinsic genomic underpinnings as survival curves remained unchanged after correcting for age, sex, blasts and IPSS-R. Importantly, no significant differences in OS and LFS were noted between the 4 PLT subgroups, suggesting that the degree of thrombocytopenia does not correlate with mortality in MDS-IT. From the diagnostic standpoint, age & lt;50 or & gt;80 years and PLT & lt;25 ×10 9/L favored a diagnosis of ITP over MDS-IT. Figure 1 Figure 1. Disclosures Viniou: Sandoz: Research Funding; Takeda: Research Funding; Novartis: Honoraria, Research Funding; Sanofi: Research Funding; Janssen: Honoraria, Research Funding; Pfizer: Research Funding; Abbvie: Research Funding; Bristol-Myers Squibb: Honoraria, Research Funding; Roche: Research Funding; Astellas: Research Funding; Celgene: Research Funding. Vassilakopoulos: Dr. Reddy's: Research Funding; Amgen: Honoraria, Research Funding; GlaxoSmithKline: Honoraria, Other: Travel; AbbVie: Consultancy, Honoraria; Integris: Honoraria; Pfizer: Research Funding; Roche: Consultancy, Honoraria, Other: Travel; Takeda: Consultancy, Honoraria, Other: Travel, Research Funding; Genesis Pharma: Consultancy, Honoraria, Other: Travel; Merck: Honoraria, Research Funding; Novartis: Consultancy, Honoraria; Karyopharm: Research Funding; AstraZeneca: Honoraria. Hatzimichael: Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; MSD: Consultancy, Honoraria; Gilead: Honoraria; Janssen Cilag: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Genesis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Abbvie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria; Pharmathen- Innovis: Honoraria; GSK: Honoraria; Bristol Myersr Squibb: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Pfizer: Consultancy, Membership on an entity's Board of Directors or advisory committees. Symeonidis: Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi/Genzyme: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Demo: Research Funding; MSD: Consultancy, Research Funding; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; WinMedica: Research Funding; Astellas: Consultancy, Research Funding; Gilead: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; GSK: Research Funding; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; GenesisPharma: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pfizer: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding.

Abstract: Introduction - Aims: Several prognostic scoring systems have been developed for patients with myelodysplastic syndromes (MDS), including the International Prognostic System (IPSS), the WHO Prognostic Scoring System (WPSS) and the Revised IPSS (IPSS-R). We evaluated the prognostic value of the IPSS-R on an independent group of 2,582 Greek patients with MDS, registered in the Hellenic National MDS Registry. The aim of this multicenter study was to validate the IPSS-R as a predictor for leukemia-free survival (LFS) and overall survival (OS), in newly-diagnosed MDS patients and to compare its prognostic significance with that of IPSS and WPSS. Moreover, to investigate the predictive value of IPSS-R in association with other recognized prognostic variables, such as patient's age, baseline serum lactate dehydrogenase (LDH), and ferritin concentrations, IPSS, WPSS, Eastern Cooperative Oncology Group (ECOG) performance status, transfusion dependency, and response to first-line treatment. Methods: Clinicopathological data from 2,582 MDS patients, diagnosed between 1/2000 - 1/2015 and registered in the Hellenic National MDS Registry were analyzed. Patients with MDS/MPN were excluded. Data included age, gender, date of diagnosis, clinical characteristics, WHO-2008 classification, laboratory parameters, transfusion dependency, bone marrow aspirate and biopsy morphology, cytogenetic findings, and type of treatment. LFS was calculated from the date of initial diagnosis of MDS until bone marrow blast increased to ≥20% [transformation to acute myeloid leukemia (AML), according to the WHO classification], or last contact. OS was defined as the time from MDS diagnosis to death, or last contact. Patients alive and not having developed AML until last follow-up were censored for OS and LFS, respectively. Kaplan-Meier survival analysis and Cox regression analysis were performed with regard to LFS and OS. Differences between Kaplan-Meier curves were evaluated using the Mantel-Cox (log-rank) test. All significant variables identified by univariate Cox regression analysis and clinical factors important for MDS were used to build the multivariate Cox regression models. Multivariate Cox regression analysis included only those patients for whom the status of all variables was known, and comprised age, serum LDH, and ferritin levels, transfusion dependency, response to first-line treatment, IPSS, WPSS, and IPSS-R. Confidence intervals (CI) were estimated at the 95% level; all tests were two-sided, accepting p 〈 0.05 as indicative of a statistically significant difference. All statistical analyses were performed with the statistical software SPSS (version 21). Results: 1,623 male (62.9%) and 959 female MDS patients with a median age of 74 years at diagnosis were included in the current study. Complete follow-up information was available for 2,376 patients. The estimated median OS was 58 months (95% CI = 52.9 - 63.1 months). For 1,974 patients, data used in the calculation of all three scoring systems were complete, thus allowing risk score calculation and comparison of the three risk assessment systems. Median OS was significantly different in patient subgroups classified according to IPSS, WPSS, and IPSS-R, as shown by the Kaplan-Meier survival analysis (p 〈 0.001). Fig. 1 shows Kaplan-Meier OS curves of MDS patients stratified according to IPSS-R (p 〈 0.001). Moreover, the comparison of the prognostic value of the IPSS, WPSS, and IPSS-R revealed that the IPSS-R was significantly superior to both, WPSS and IPSS (p 〈 0.001 in all cases). Multivariate Cox regression analysis demonstrated that the high prognostic value of IPSS-R, in terms of LFS and OS, was independent of patient's age, serum LDH, and ferritin concentration, ECOG performance status, and transfusion dependency (p 〈 0.001). Interestingly, besides IPSS-R, patient age and transfusion dependency retain their small - yet significant - prognostic impact in the multiparametric models, thus implying that these two parameters could add prognostic value to the IPSS-R. Conclusions: Our data support the notion that all three prognostic scores are very useful predictors for both, LFS and OS in MDS, yet IPSS-R is superior to IPSS and WPSS as a prognostic tool, with regard to OS. Disclosures No relevant conflicts of interest to declare.