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Background Patients with chronic lymphocytic leukemia (CLL) may be more susceptible to COVID-19 related poor outcomes, including thrombosis and death, due to the advanced age, the presence of comorbidities, and the disease and treatment-related immune deficiency. The aim of this study was to assess the risk of thrombosis and bleeding in patients with CLL affected by severe COVID-19. Methods This is a retrospective multicenter study conducted by ERIC, the European Research Initiative on CLL, including patients from 79 centers across 22 countries. Data collection was conducted between April and May 2021. The COVID-19 diagnosis was confirmed by the real-time polymerase chain reaction (RT-PCR) assay for SARS-CoV-2 on nasal or pharyngeal swabs. Severe cases of COVID-19 were defined by hospitalization and the need of oxygen or admission into ICU. Development and type of thrombotic events, presence and severity of bleeding complications were reported during treatment for COVID-19. Bleeding events were classified using ISTH definition. STROBE recommendations were used in order to enhance reporting. Results A total of 793 patients from 79 centers were included in the study with 593 being hospitalized (74.8%). Among these, 511 were defined as having severe COVID: 162 were admitted to the ICU while 349 received oxygen supplementation outside the ICU. Most patients (90.5%) were receiving thromboprophylaxis. During COVID-19 treatment, 11.1% developed a thromboembolic event, while 5.0% experienced bleeding. Thrombosis developed in 21.6% of patients who were not receiving thromboprophylaxis, in contrast to 10.6% of patients who were on thromboprophylaxis. Bleeding episodes were more frequent in patients receiving intermediate/therapeutic versus prophylactic doses of low-molecular-weight heparin (LWMH) (8.1% vs. 3.8%, respectively) and in elderly. In multivariate analysis, peak D-dimer level and C-reactive protein to albumin ratio were poor prognostic factors for thrombosis occurrence (OR = 1.022, 95%CI 1.007‒1.038 and OR = 1.025, 95%CI 1.001‒1.051, respectively), while thromboprophylaxis use was protective (OR = 0.199, 95%CI 0.061‒0.645). Age and LMWH intermediate/therapeutic dose administration were prognostic factors in multivariate model for bleeding (OR = 1.062, 95%CI 1.017–1.109 and OR = 2.438, 95%CI 1.023–5.813, respectively). Conclusions Patients with CLL affected by severe COVID-19 are at a high risk of thrombosis if thromboprophylaxis is not used, but also at increased risk of bleeding under the LMWH intermediate/therapeutic dose administration.

Autoimmune cytopenias (AICs) affect 5% to 9% of patients with chronic lymphocytic leukemia (CLL). Targeted drugs—ibrutinib, idelalisib, and venetoclax—have a prominent role in the treatment of CLL, but their impact on CLL-associated AICs is largely unknown. In this study, we evaluated the characteristics and outcome of preexisting AICs and described the incidence, quality, and management of treatment-emergent AICs during therapy with targeted drugs in patients with CLL. We collected data from 572 patients treated with ibrutinib (9% in combination with an anti-CD20 monoclonal antibody), 143 treated with idelalisib-rituximab, and 100 treated with venetoclax (12% in combination with an anti-CD20 monoclonal antibody). A history of preexisting AICs was reported in 104 (13%) of 815 patients. Interestingly, 80% of patients whose AICs had not resolved when treatment with a targeted drug was started experienced an improvement or a resolution during therapy. Treatment-emergent AICs occurred in 1% of patients during ibrutinib therapy, in 0.9% during idelalisib therapy, and in 7% during venetoclax therapy, with an estimated incidence rate of 5, 6, and 69 episodes per 1000 patients per year of exposure in the 3 treatment groups, respectively. The vast majority of patients who developed treatment-emergent AICs had unfavorable biological features such as an unmutated IGHV and a del(17p) and/or TP53 mutation. Notably, despite AICs, 83% of patients were able to continue the targeted drug, in some cases in combination with additional immunosuppressive agents. Overall, treatment with ibrutinib, idelalisib, or venetoclax seems to have a beneficial impact on CLL-associated AICs, inducing an improvement or even a resolution of preexisting AICs in most cases and eliciting treatment-emergent AICs in a negligible portion of patients.

Introduction: Patients (pts) with CLL may be at particular risk of severe COVID-19 given advanced age and immune dysregulation. Two large series with limited follow-up have reported outcomes for pts with CLL and COVID-19 (Scarfò, et al. Leukemia 2020; Mato, et al. Blood 2020). To provide maximal clarity on outcomes for pts with CLL and COVID-19, we partnered in a worldwide effort to describe the clinical experience and validate predictors of survival, including potential treatment effects. Methods: This international collaboration represents a partnership between investigators at 141 centers. Data are presented in two cohorts. Cohort 1 (Co1) includes pts captured through efforts by European Research Initiative on CLL (ERIC), Italian CAMPUS CLL Program, and Grupo Español de Leucemia Linfática Crónica. The validation cohort, Cohort 2 (Co2), includes pts from US (66%), UK (23%), EU (7%), and other countries (4%). There is no overlap in cases between cohorts. CLL pts were included if COVID-19 was diagnosed by PCR detection of SARS-CoV-2 and they required inpatient hospitalization. Data were collected retrospectively 2/2020 - 5/2020 using standardized case report forms. Baseline characteristics, preexisting comorbidities (including cumulative illness rating scale (CIRS) score ≥6 vs. The primary endpoint of this study was to estimate the case fatality rate (CFR), defined as the proportion of pts who died among all pts hospitalized with COVID-19. Chi-squared test was used to compare frequencies; univariable and multivariable analyses utilized Cox regression. Predictors of inferior OS in both Co1 and Co2 were included in multivariable analyses. Kaplan-Meier method was used to estimate overall survival (OS) from time of COVID-19 diagnosis (dx). Results: 411 hospitalized, COVID-19 positive CLL pts were analyzed (Co1 n=281, Co2 n=130). Table 1 describes baseline characteristics. At COVID-19 dx, median age was 72 in Co1 (range 37-94) and 68 in Co2 (range 41-98); 31% (Co1) and 45% (Co2) had CIRS ≥6. In Co1, 48% were treatment-naïve and 26% were receiving CLL-directed therapy at COVID-19 dx (66% BTKi ± anti-CD20, 19% Venetoclax ± anti-CD20, 9.6% chemo/chemoimmunotherapy (CIT), 1.4% PI3Ki, 4% other). In Co2, 36% were never treated and 49% were receiving CLL-directed therapy (65% BTKi ± anti-CD20, 19% Venetoclax ± anti-CD20, 9.4% multi-novel agent combinations, 1.6% CIT, 1.6% PI3Ki, 1.6% anti-CD20 monotherapy, 1.6% other). Most pts receiving CLL-directed therapy had it held at COVID-19 diagnosis (93% in Co1 and 81% in Co2). Frequency of most COVID-19 symptoms/laboratory abnormalities were similar in the two cohorts including fever (88% in both), lymphocytosis (ALC ≥30 x 109/L; 27% vs. 21%), and lymphocytopenia (ALC < 1.0 x 109/L; 18% vs. 28%), while others varied between Co1 and Co2 (p Median follow-up was 24 days (range 2-86) in Co1 and 17 days (1-43) in Co2. CFRs were similar in Co1 and Co2, 30% and 34% (p=0.45). 54% and 43% were discharged while 16% and 23% remained admitted at last follow-up in Co1 and Co2, respectively. The proportion of pts requiring supplemental oxygen was similar (89% vs. 92%) while rate of ICU admission was higher in Co2 (20% vs. 48%, p Conclusions : In the largest cancer dx-specific cohort reported, pts with CLL hospitalized for COVID-19 had a CFR of 30-34%. Advanced patient age at COVID-19 diagnosis was an independent predictor of OS in two large cohorts. This CFR will serve as a benchmark for mortality for future outcomes studies, including therapeutic interventions for COVID-19 in this population. The effect of CLL treatment on OS was inconsistent across cohorts; COVID-19 may be severe regardless of treatment status. While there were no significant differences in distribution of current lines of therapy between cohorts, prior chemo exposure was more common in Co1 vs. Co2, which may account for difference in OS. Extended follow-up will be presented. Disclosures Roeker: American Society of Hematology: Research Funding; Abbott Laboratories: Other: spouse with minority ownership interest ; AbbVie: Other: spouse with minority ownership interest . Scarfo:Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; AstraZeneca: Honoraria; Gilead: Membership on an entity's Board of Directors or advisory committees. Abrisqueta:Celgene: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Speakers Bureau; Roche: Consultancy, Honoraria, Speakers Bureau; AbbVie: Consultancy, Honoraria, Speakers Bureau. Eyre:AbbVie: Consultancy, Honoraria, Other: travel support; Gilead: Consultancy, Honoraria, Other: travel support; Janssen: Consultancy, Honoraria, Other: travel support; KITE, AZ, Loxo Oncology at Lilly: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Muntañola Prat:Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel grants; participated in advisory boards; Abbvie: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel grants; participated in advisory boards; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel grants; participated in advisory boards. Villacampa:AstraZeneca: Other: advisory role; Merck Sharp & Dohme: Honoraria. Leslie:AstraZeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Bayer: Consultancy, Membership on an entity's Board of Directors or advisory committees; ADC therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees; AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees; BeiGene: Speakers Bureau; KitePharma: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene/BMS: Speakers Bureau; Seattle Genetics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Pharmacyclics/Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Epizyme: Speakers Bureau; Karyopharm: Speakers Bureau; TG Therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees. Allan:Acerta, Genentech, Abbvie, Sunesis, Ascentage, Pharmacyclics, Janssen, AstraZeneca, BeiGene: Consultancy; Celgene, Genentech, Janssen, TG Therapeutics: Research Funding; Abbvie, Janssen, AstraZeneca, Pharmacyclics: Honoraria. Furman:Incyte: Consultancy; Genentech: Consultancy; Sunesis: Consultancy; Pharmacyclics: Consultancy; Loxo Oncology: Consultancy; Oncotarget: Consultancy; Janssen: Consultancy, Speakers Bureau; TG Therapeutics: Consultancy, Research Funding; Abbvie: Consultancy; Beigene: Consultancy; AstraZeneca: Consultancy, Research Funding; Acerta: Consultancy; Verastem: Consultancy. Pagel:BeiGene, Astrazeneca, Loxo Oncology, Gilead: Consultancy. Hernandez-Rivas:Gilead: Membership on an entity's Board of Directors or advisory committees; Celgene/BMS: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees; AstraZeneca: Membership on an entity's Board of Directors or advisory committees; Rovi: Membership on an entity's Board of Directors or advisory committees. Patel:Genentech: Consultancy, Speakers Bureau; Adaptive Biotechnologies: Consultancy; Janssen: Consultancy, Speakers Bureau; Celgene/BMS: Consultancy, Membership on an entity's Board of Directors or advisory committees; BeiGene: Consultancy; Kite: Consultancy; Pharmacyclics: Consultancy, Speakers Bureau; AstraZeneca: Consultancy, Research Funding, Speakers Bureau. Motta:Roche: Honoraria; Janssen: Honoraria. Lamanna:AbbVie: Membership on an entity's Board of Directors or advisory committees, Research Funding; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees, Research Funding; AstraZeneca: Membership on an entity's Board of Directors or advisory committees; Genentech: Research Funding; Verastem: Research Funding; Bei-Gene: Research Funding; TG Therapeutics: Research Funding; Acerta: Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche-Genentech: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees. Vitale:Janssen: Honoraria. Kamdar:Roche: Research Funding. Österborg:BeiGene: Research Funding; Kancera: Current equity holder in publicly-traded company, Research Funding; Sanofi: Consultancy; Karolinska Univeristy Hospital, Stockholm, Sweden: Current Employment. Hanson:Janssen-Cilag: Research Funding; Gilead: Research Funding; AbbVie: Honoraria. Eichhorst:ArQule: Consultancy, Honoraria, Other: travel support, Research Funding; BeiGene: Consultancy, Honoraria, Other: travel support, Research Funding; Gilead: Consultancy, Honoraria, Other: travel support, Research Funding; AstraZeneca: Consultancy, Honoraria, Other: travel support, Research Funding; Oxford Biomedica: Consultancy, Honoraria, Other: travel support, Research Funding; AbbVie: Consultancy, Honoraria, Other: travel support, Research Funding; F. Hoffmann-LaRoche: Consultancy, Honoraria, Other: travel support, Research Funding; Janssen-Cilag: Consultancy, Honoraria, Other: travel support, Research Funding; Celgene: Consultancy, Honoraria, Other: travel support, Research Funding; Novartis: Consultancy, Honoraria, Other: travel support, Research Funding. Reda:Gilead: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees. Varettoni:Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Travel/accommodations/expenses; AbbVie: Other: Travel/accommodations/expenses; Roche: Consultancy, Membership on an entity's Board of Directors or advisory committees. Marchetti:Gilead: Consultancy; Novartis: Speakers Bureau; Amgen: Speakers Bureau; AbbVie: Other: Sponsored meetings; Takeda: Other: Sponsored meetings; Pfeizer: Other: Sponsored meetings. Munir:F. Hoffmann-La Roche: Consultancy, Other: Medical writing support, furnished by Scott Battle, PhD, of Health Interactions, was funded by F. Hoffmann-La Roche Ltd, Basel, Switzerland; Alexion: Honoraria. Zabalza:Janssen: Honoraria, Other: travel grants; Roche: Other: travel grants; Novartis: Other: travel grants. Janssens:Amgen: Consultancy, Other: travel grants; speaker fees; Abbvie: Consultancy, Other: travel grants; speaker fees; Celgene: Consultancy, Other: travel grants; speaker fees; Janssen: Consultancy, Other: travel grants; speaker fees; Gilead: Consultancy, Other: travel grants; speaker fees; Novartis: Consultancy, Other: travel grants; speaker fees; Sanofi-Genzyme: Consultancy, Other: travel grants; speaker fees; Roche: Consultancy, Other: travel grants; speaker fees. Niemann:AstraZeneca: Honoraria, Research Funding; CSL Behring: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Sunesis: Honoraria, Research Funding; Abbvie: Honoraria, Research Funding; Danish Cancer Society: Honoraria, Research Funding; Novo Nordisk Foundation: Honoraria, Research Funding. Perini:Takeda: Honoraria; Janssen: Honoraria, Speakers Bureau; Abbvie: Speakers Bureau. Patten:AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Honoraria; Gilead: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Astra Zeneca: Honoraria. Marasca:Roche: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Shire: Honoraria. Iyengar:Janssen: Honoraria; Gilead: Honoraria. Ferrari:Abbvie: Honoraria. El-Sharkawi:Roche: Other: Conference fees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees. Itchaki:Abbvie Inc: Consultancy, Research Funding. Ma:Novartis: Research Funding; Juno: Research Funding; Pharmacyclics, LLC, an AbbVie Company: Consultancy, Honoraria, Research Funding, Speakers Bureau; Kite: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Research Funding, Speakers Bureau; Gilead: Consultancy, Honoraria; Genentech: Consultancy, Honoraria; Bioverativ: Consultancy, Honoraria; BeiGene: Honoraria, Research Funding, Speakers Bureau; AstraZeneca: Consultancy, Honoraria, Research Funding, Speakers Bureau; AbbVie: Consultancy, Honoraria, Research Funding; TG Therapeutics: Research Funding. Van Der Spek:AMGEN: Other: Teaching activities. Seymour:Seattle Genetics: Research Funding; Merck: Research Funding; Karyopharm: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen/Pharmacyclics: Membership on an entity's Board of Directors or advisory committees; Incyte: Research Funding; Genentech: Research Funding; Bristol-Myers Squibb: Research Funding. Rigolin:Gilead: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Abbvie: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Mauro:Roche: Other; Octopharma: Other; Takeda-Shire: Other; Gilead: Other; Janssen: Other; Abbvie: Other. Laurenti:Janssen: Honoraria; Gilead: Honoraria; AbbVie: Honoraria; Roche: Honoraria. Levin:Janssen: Membership on an entity's Board of Directors or advisory committees, Other: travel compensation; Abbvie: Membership on an entity's Board of Directors or advisory committees, Other: travel compensation; Roche: Membership on an entity's Board of Directors or advisory committees, Other: travel compensation. Špaček:Gilead: Honoraria; Abbvie: Honoraria; Janssen: Honoraria. Walewska:AbbVie: Other: sponsored for educational meetings, Speakers Bureau; Janssen: Other: sponsored for educational meetings, Speakers Bureau; Gilead: Speakers Bureau; Astra Zeneca: Membership on an entity's Board of Directors or advisory committees. Wiestner:Pharmacyclics LLC, an AbbVie Company; Acerta, Merck, Nurix, Verastem, and Genmab: Research Funding; National Institutes of Health: Patents & Royalties: and other intellectual property. Broom:Gilead: Other: Travel support, Speakers Bureau. Kater:Abbvie: Research Funding; Roche: Research Funding; Janssen: Research Funding; Celgene: Research Funding; Genentech: Research Funding. Ujjani:AstraZeneca: Consultancy, Honoraria, Research Funding; Abbvie: Consultancy, Honoraria, Research Funding; Verastem Oncology: Consultancy, Honoraria; Gilead/Kite: Consultancy, Research Funding; Atara: Consultancy, Honoraria; Genentech: Consultancy, Honoraria; MorphoSys: Consultancy. Vandenberghe:Celgene: Other: sponsorship to attend Lugano lymphoma meeting in 2019; Gilead: Other: travel grants, Research Funding; Abbvie: Other: travel grants, Research Funding; Janssen: Other: travel grants; Roche: Other: travel grants, Research Funding. Chong:Novartis: Membership on an entity's Board of Directors or advisory committees; Tessa: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees; KITE Pharma: Membership on an entity's Board of Directors or advisory committees. Pu:Takeda Pharmaceuticals: Consultancy. Brown:Janssen, Teva: Speakers Bureau; Gilead, Loxo, Sun, Verastem: Research Funding; Abbvie, Acerta, AstraZeneca, Beigene, Invectys, Juno/Celgene, Kite, Morphosys, Novartis, Octapharma, Pharmacyclics, Sunesis, TG Therapeutics, Verastem: Consultancy. Trentin:Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Abbvie: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Octapharma: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; Shire: Honoraria. Farina:Abbvie: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees. Sanchez:Abbvie: Other: travel grants; Amgem: Other: travel grants; Janssen: Other: travel grants; Celgene: Other: travel grants; Roche: Other: travel grants. Shadman:Abbvie, Genentech, Astra Zeneca, Sound Biologics , Pharmacyclics, Verastem, ADC therapeutics, Beigene, Cellectar, BMS, Morphosys and Atara Biotherapeutics: Consultancy; Mustang Bio, Celgene, Pharmacyclics, Gilead, Genentech, Abbvie, TG therapeutics, Beigene, Astra Zeneca, Sunesis, Beigene: Research Funding. Foglietta:Janssen: Honoraria; Gilead: Honoraria. Jaksic:Roche: Honoraria; Janssen: Honoraria; Abbvie: Honoraria. Sportoletti:AbbVie: Honoraria; Janssen: Honoraria. Barr:Morphosys: Consultancy; Gilead: Consultancy; AstraZeneca: Consultancy, Research Funding; Verastem: Consultancy; Seattle Genetics: Consultancy; TG therapeutics: Consultancy, Research Funding; Abbvie/Pharmacyclics: Consultancy, Research Funding; Celgene: Consultancy; Merck: Consultancy; Genentech: Consultancy; Janssen: Consultancy. Ruchlemer:Abbvie Inc: Consultancy, Research Funding. Kersting:Celgene: Other: travel grant; Janssen: Research Funding; Abbvie: Research Funding. Huntington:Pharmacyclics: Honoraria; AbbVie: Consultancy; Novartis: Consultancy; Genentech: Consultancy; DTRM: Research Funding; Celgene: Consultancy, Research Funding; Bayer: Consultancy, Honoraria; Astrazeneca: Honoraria; TG Therapeutics: Research Funding. Herishanu:Roche: Honoraria; Sanofi: Honoraria; Medison: Honoraria; Janssen: Honoraria; Abbvie: Honoraria; AstraZeneca: Honoraria. Jacobs:TG Therapeutics, Inc.: Research Funding; Astra Zeneca: Consultancy, Speakers Bureau; AbbVie: Consultancy, Speakers Bureau; Pharmacyclics: Research Funding, Speakers Bureau; Seattle Genetics: Consultancy; Verastem: Consultancy; Janssen: Consultancy, Speakers Bureau; Genentech: Speakers Bureau; Sanofi Genzyme: Speakers Bureau. Portell:BeiGene: Consultancy, Research Funding; Pharmacyclics: Consultancy; TG Therapeutics: Research Funding; Infinity: Research Funding; Roche/Genentech: Consultancy, Research Funding; Xencor: Research Funding; Bayer: Consultancy; Amgen: Consultancy; Janssen: Consultancy; Kite: Consultancy, Research Funding; Acerta/AstraZeneca: Research Funding; AbbVie: Research Funding. Rambaldi:Sanofi: Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); Astellas: Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); BMS/Celgene: Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); University of Milan: Current Employment; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Support of parent study and funding of editorial support. Received travel support., Research Funding; Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel support from Gilead.; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company). Research grant from Amgen Inc.; Omeros: Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company). Advisory board and speaker fees from Pfizer.. Brander:Verastem: Consultancy, Honoraria, Other, Research Funding; NCCN: Other; Novartis: Consultancy, Other; Teva: Consultancy, Honoraria; Tolero: Research Funding; NCCN: Other; Novartis: Consultancy, Other; Teva: Consultancy, Honoraria; Tolero: Research Funding; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other, Research Funding; ArQule: Consultancy, Other, Research Funding; Ascentage: Other, Research Funding; AstraZeneca: Consultancy, Honoraria, Other, Research Funding; BeiGene: Other, Research Funding; DTRM: Other, Research Funding; Genentech: Consultancy, Honoraria, Other, Research Funding; Juno/Celgene/BMS: Other, Research Funding; MEI Pharma: Other, Research Funding; Pharmacyclics LLC, an AbbVie Company: Consultancy, Honoraria, Other, Research Funding; Pfizer: Consultancy, Other; TG Therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other, Research Funding. Rossi:Abbvie: Membership on an entity's Board of Directors or advisory committees; Daiichi Sankyo: Consultancy, Honoraria; Celgene: Membership on an entity's Board of Directors or advisory committees; Jazz: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Novartis: Other: Advisory board; Astellas: Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria; Pfizer: Membership on an entity's Board of Directors or advisory committees; Alexion: Membership on an entity's Board of Directors or advisory committees; Sanofi: Honoraria; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees. Coscia:Karyopharm Therapeutics: Research Funding; Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees; Shire: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Abbvie: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Coombs:Abbvie: Consultancy, Honoraria; Genentech: Honoraria; AstraZeneca: Honoraria; MEI Pharma: Honoraria; LOXO Oncology: Honoraria; Octapharma: Honoraria; Novartis: Honoraria. Schuster:Novartis, Genentech, Inc./ F. Hoffmann-La Roche: Research Funding; AlloGene, AstraZeneca, BeiGene, Genentech, Inc./ F. Hoffmann-La Roche, Juno/Celgene, Loxo Oncology, Nordic Nanovector, Novartis, Tessa Therapeutics: Consultancy, Honoraria. Foà:Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Roche: Membership on an entity's Board of Directors or advisory committees; Novartis: Speakers Bureau; Roche: Membership on an entity's Board of Directors or advisory committees; Incyte: Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Cuneo:Astra Zeneca: Honoraria; Gilead: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Roche: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Bosch:Jansen: Honoraria; Abbvie: Honoraria; Novartis: Honoraria; Astra Zeneca: Honoraria; Takeda: Honoraria; Celgene: Honoraria; Roche: Honoraria. Stamatopoulos:AstraZeneca: Honoraria; Janssen, Gilead, Abbvie: Honoraria, Research Funding. Ghia:Adaptive, Dynamo: Consultancy, Honoraria; Novartis: Research Funding; BeiGene: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company), Research Funding; Celgene/Juno: Consultancy, Honoraria; Lilly: Consultancy, Honoraria; MEI: Consultancy, Honoraria; Sunesis: Consultancy, Honoraria, Research Funding; AbbVie: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company), Research Funding; Gilead: Consultancy, Honoraria, Research Funding; ArQule: Consultancy, Honoraria; Acerta/AstraZeneca: Consultancy, Honoraria. Mato:Adaptive: Consultancy, Research Funding; Janssen: Consultancy, Research Funding; AbbVie: Consultancy, Research Funding; BeiGene: Consultancy; LOXO: Consultancy, Research Funding; Genentech: Consultancy, Research Funding; AstraZeneca: Consultancy, Research Funding; Pharmacyclics LLC, an AbbVie Company: Consultancy, Research Funding; TG Therapeutics: Consultancy, Other: DSMB, Research Funding.

Fixed-duration treatment with venetoclax (Ven), a highly selective Bcl-2 inhibitor combined with an anti-CD20 monoclonal antibody, showed high efficacy inducing high rates of deep responses with undetectable minimal residual disease (uMRD) in patients with previously treated and untreated chronic lymphocytic leukemia (CLL). The efficacy and safety of the Ven and rituximab (VenR) combination have been investigated in a multicenter, prospective study of the GIMEMA group that included young patients with previously untreated CLL (LLC 1518, VERITAS, NCT03455517). The primary endpoint of this study was the CR rate assessed according to the iwCLL criteria. Inclusion criteria were: treatment requirement per iwCLL criteria, age ≤65 years, cumulative Illness rating scale score ≤6, creatinine clearance ≥30 mL/min, and an unfavorable biologic profile with IGHV unmutated and or TP53 disruption. Treatment consisted of the Ven dose ramp-up (from 20 to 400 mg daily, during 5-weeks) followed by Ven 400 mg daily, combined with R for six 28-day courses (375 mg/m2, course 1; 500 mg/m2, courses 2-6). Patients continued with Ven single agent, 400 mg daily, until month 13. Tumor lysis syndrome (TLS) prophylaxis measures included hydration, allopurinol, or rasburicase. All patients received PneumocystisJirovecii prophylaxis. G-CSF was given in patients with recurrent and severe granulocytopenia. Adverse events (AEs) were graded according to the CTCAE criteria v.5, TLS events were classified according to Howard's criteria. Response was assessed at months 7 and 15 and included clinical examination, PB evaluation, BM aspirate, BM biopsy, and CT scan. MRD was checked centrally in the PB and BM by a 6/4-color flow-cytometry assay with a sensitivity of at least 10-4 according to the internationally standardized European Research Initiative on CLL. Quantitative MRD results assessed by flow-cytometry were categorized as uMRD (uMRD4; Between October 2018 and May 2020, 77 patients with CLL were included in this study. Two patients were off study before the start of treatment (withdrawal of consent, 1; Covid-19 infection, 1) and were not included in the analysis. The median age was 53.5 years (range 38-65). Binet stage B/C was present in 84% of patients, increased beta-2 microglobulin in 41%. Seventy-one (96%) of patients were IGHV unmutated, while 3 (4%) were IGHV mutated and showed TP53 mutation (Table 1). At the data cutoff of June 30, 2020, 65 (87%) patients completed the ramp-up phase. The planned 400 mg dose of Ven was reached within 5 weeks in 78.5% of patients. Response was assessed in 34 patients at the end of the VenR combination therapy. A response was achieved by 32 (94%) patients. Responses included 20 (59%) CRs, 1 CRi (3%) and 11 (32%) PRs due to residual enlarged nodes (median maximum size, 1.9 cm). Treatment failure due to toxicity was recorded in 2 (6%) patients. Overall, a response with uMRD4 by flow-cytometry in the PB was observed in 26 (76.5%) cases, and in the PB and BM, in 17 (50.0%). The rates of patients with CR and uMRD4 by flow-cytometry in the PB, and both in the PB and BM, were 44%, and 35%, respectively (Table 2). No detectable disease by PCR, both in the PB and BM, was observed in 4 (12%) patients. With a median follow-up of 4.5 months from the start of therapy, no patient has progressed or died. Fifty-three percent of patients were hospitalized during the first seven days of the Ven ramp-up phase. A transient laboratory TLS was observed in 3 patients. Treatment was discontinued after the first dose of Ven in 1 patient with evidence of laboratory TLS associated with severe neurologic toxicity due to the concomitant administration of fentanyl. Selected grade ≥3 AEs included neutropenia in 10 patients (ramp-up phase, 5) and neutropenic fever in 4. Grade ≥3 infection was recorded in 3 patients and was the reason for treatment discontinuation in 1 who developed COVID-19 pneumonia. In conclusion, the preliminary results of this study demonstrate the high efficacy of the front-line VenR combination, which resulted in a high proportion of CRs and responses with uMRD4 in young patients with CLL and an unfavorable biologic profile. Disclosures Mauro: Astrazeneca: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Jannsen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Octopharma: Consultancy. Reda:Gilead: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees. Trentin:Abbvie: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Shire: Honoraria; Takeda: Membership on an entity's Board of Directors or advisory committees; Octapharma: Membership on an entity's Board of Directors or advisory committees. Coscia:Shire: Honoraria, Membership on an entity's Board of Directors or advisory committees; Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees; Karyopharm Therapeutics: Research Funding; Abbvie: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Sportoletti:Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Laurenti:Roche: Membership on an entity's Board of Directors or advisory committees; AbbVie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Gilead: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Gaidano:Astrazeneca: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Sunesys: Membership on an entity's Board of Directors or advisory committees. Marasca:Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Shire: Honoraria; Roche: Membership on an entity's Board of Directors or advisory committees. Murru:Gilead: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Rigolin:Gilead: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Abbvie: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Scarfo:Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; AstraZeneca: Honoraria; Gilead: Membership on an entity's Board of Directors or advisory committees. Marchetti:Pfizer: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees. Levato:Gilead: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Galieni:Celgene: Honoraria; Takeda: Honoraria; AbbVie: Honoraria; Janssen: Honoraria. Liberati:Verastem: Research Funding; Onconova: Research Funding; Janssen: Honoraria, Research Funding; Roche: Membership on an entity's Board of Directors or advisory committees, Research Funding; Abbvie: Honoraria, Research Funding; Pfizer: Research Funding; Karyopharm: Research Funding; Morphosys: Research Funding; Novartis: Research Funding; GSK: Research Funding; Incyte: Honoraria; Oncopeptides: Research Funding; Takeda: Research Funding. Molica:Roche: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Gilead: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Visentin:Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Gilead: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Vitale:Janssen: Honoraria. Del Giudice:Janssen: Other: grant for meeting participation; Tolero: Membership on an entity's Board of Directors or advisory committees; Roche: Other: grant for meeting partecipation; AstraZeneca: Membership on an entity's Board of Directors or advisory committees. Cuneo:Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Roche: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Astra Zeneca: Honoraria; Gilead: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Foà:Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Incyte: Speakers Bureau; Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Roche: Membership on an entity's Board of Directors or advisory committees; Novartis: Speakers Bureau; Roche: Membership on an entity's Board of Directors or advisory committees.

Introduction: In previously untreated patients with chronic lymphocytic leukemia (CLL), treatment with ibrutinib plus rituximab improved progression-free survival (PFS) and overall survival (OS) compared to the standard fludarabine, cyclophosphamide and rituximab (FCR) chemoimmunotherapeutic regimen, based on the results of the phase III ECOG-E1912 trial. The improvement in PFS with ibrutinib plus rituximab was observed in patients with unmutated immunoglobulin heavy chain variable region gene (IGHV) but not in those with an IGHV mutated profile. However, the efficacy of ibrutinib compared to FCR has not yet been investigated in the real-world setting. Methods: A multi-center retrospective "real-world" study to compare the efficacy of front-line ibrutinib monotherapy versus standard FCR in patients with CLL. Demographic and clinical data of the FCR cohort were retrieved from the Israeli CLL Study Group database and of the ibrutinib from the Italian multicenter "Campus CLL" network and the CLL database of the department of hematology at the Sourasky Medical Center. Patients with a documented del(17p) or those who are participating in clinical trials were excluded. In order to fit both treatment samples, the maximum follow-up was censored at 48 months. IBM SPSS Statistics was used to analyze PFS and OS by Kaplan Meier Estimator, Log-Rank test and Cox Regression. In order to control for differences in patients' characteristics, the inverse probability of treatment weighting (IPTW) method with stabilized weights and truncation of 5% extreme score was applied by R. Results: A total of 235 patients who had been front-line treated with either FCR (n=136, 57.9%) or ibrutinib (n=99, 42.1%) were included (Table 1). Most patients were males (n=160, 68.1%), had an unmutated IGHV status (n=115, 70.6%) and were Binet stage B/C (n=191, 83.8%). By FISH, the most frequent abnormality was del(11q) (n=45, 23.1%) followed by trisomy12 (n=34, 17.4%) and del(13q) (n=43, 22.1%). Median time to first treatment was 29.4 months (IQR, 11.9-56.2), and it was not significantly different between ibrutinib (median=24.9 months, IQR 10.3-46.6) and FCR (median=34.0 months, IQR 13.8-60.1; p=0.101). Patients treated with FCR were younger than those treated with ibrutinib (median=58.4 years vs. 71.9 years; p65 years (n=100, 3-year PFS 89.4% vs. 53.1%; HR=3.9, 95% CI [1.6-9.9], p=0.002), Binet stage B/C (3-year PFS: 90.5% vs. 67.8%; HR=3.5, 95% CI [1.7-7.5], p Conclusions: In a real-world setting, front-line treatment with ibrutinib improves PFS and OS in patients with CLL. Similar to the results of the phase III ECOG-E1912 trial, the improvement in PFS was preferentially observed in patients with unmutated IGHV. Figure 1 Figure 1. Disclosures Herishanu: AbbVie: Honoraria, Research Funding; Janssen: Honoraria; Roche: Honoraria; Medison: Honoraria. Goldschmidt: AbbVie: Consultancy, Research Funding. Fineman: AbbVie: Research Funding. Mauro: Roche: Consultancy, Honoraria; Gilead: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria, Speakers Bureau; Astra Zeneca: Consultancy, Honoraria, Speakers Bureau; Janssen: Consultancy, Honoraria, Speakers Bureau; Tskeda: Consultancy, Honoraria. Reda: Abbvie: Consultancy; Astra Zeneca: Consultancy; Beigene: Consultancy; Janssen: Consultancy. Ruchlemer: AbbVie: Consultancy, Honoraria, Research Funding. Sportoletti: AstraZeneca: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria. Laurenti: AstraZeneca: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria, Research Funding; Gilead: Honoraria; Roche: Honoraria, Research Funding; Janssen: Consultancy, Honoraria; BeiGene: Honoraria. Shvidel: AbbVie: Honoraria, Research Funding. Coscia: Janssen: Honoraria, Other, Research Funding; Gilead: Honoraria; AbbVie: Honoraria, Other; AstraZeneca: Honoraria. Tadmor: Janssen: Consultancy, Honoraria, Research Funding; AbbVie: Consultancy, Honoraria, Research Funding. Varettoni: AstraZeneca: Membership on an entity's Board of Directors or advisory committees; beigene: Membership on an entity's Board of Directors or advisory committees; janssen: Membership on an entity's Board of Directors or advisory committees; roche: Membership on an entity's Board of Directors or advisory committees. Aviv: AbbVie: Honoraria, Research Funding. Murru: Abbvie: Consultancy, Honoraria, Other: travel and accommodation; Janssen: Consultancy, Honoraria. Rossi: Abbvie: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; AstraZeneca: Honoraria, Research Funding; Gilead: Honoraria, Research Funding; Verastem: Honoraria, Research Funding; Roche: Honoraria, Research Funding; Cellestia: Honoraria, Research Funding. Gaidano: Incyte: Membership on an entity's Board of Directors or advisory committees; Beigene: Membership on an entity's Board of Directors or advisory committees; Astrazeneca: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Cuneo: AbbVie: Consultancy, Speakers Bureau; Gilead: Consultancy, Speakers Bureau; AstraZeneca: Consultancy, Speakers Bureau; Janssen: Consultancy, Speakers Bureau. Gattei: abbVie: Research Funding; Janssen: Research Funding; Menarini: Research Funding.

Introduction Ibrutinib is the only once-daily Bruton's tyrosine kinase (BTK) inhibitor with significant survival benefit vs chemo- and /or immunotherapy in multiple phase 3 studies of patients (pts) with chronic lymphocytic leukemia (CLL). It has profoundly changed the treatment landscape of CLL with the longest follow-up. However, seven years (yrs) after ibrutinib was approved in Italy by regulatory agencies for CLL treatment, available data on the patterns of care of such pts in the setting of clinical practice is limited. Herein we present the first interim analysis (IA) of EVIdeNCE (ClinicalTrials.gov Identifier: NCT03720561), a multicenter, observational clinical study designed to describe the current management of pts receiving ibrutinib in real-world setting in Italy in terms of retention rate: the study's primary end point. Methods EVIDENCE 312 treatment-naïve (TN) 38% and relapsed/refractory (R/R) 62% pts with CLL according to the iwCLL diagnosis criteria observed at 39 Italian hematological institutions in the period between November 2018 and October 2019. Inclusion criteria were treatment with ibrutinib according to the European Summary of Product Characteristics as per routine clinical practice started within the previous 3 months. The purpose of this IA is to provide demographics and disease characteristics at baseline and a preliminary evaluation of ibrutinib retention rate after one year of follow-up, along with its safety profile. Results The median age of pts at the time of ibrutinib initiation was 71.0 yrs (range 41.0-89.0), with 60% ≥70 yrs, 63.2% male, and 90% with Eastern Cooperative Oncology Group (ECOG) performance 0-1. Baseline Rai stage 0-I, II, and III-IV accounted for 18.3%, 29.7% and 52.1% pts, respectively. Patients in stage IV were observed in 40% of the R/R and 27% in TN subgroup. Considering 120 pts with known mutational status, del(17p) and/or TP53 mutation were present in 50.0% of pts (TN=52.1%, R/R=48.6%), while IGHV was unmutated in 35.0% (TN=33.3% and R/R=36.15) and mutated in 15.0% (TN=14.6%, R/R=15.3%). At baseline, 62.9% of pts had comorbidities and 30.6% presented with a history of cardiovascular diseases (CVDs). A CIRS score ≥6 was observed in 28.5% of pts. The median time from CLL diagnosis to the start of ibrutinib was 5.1 yrs (TN 1.75 yrs vs R/R 7.27 yrs). At least 1 treatment-emergent adverse event (TEAE) of any grade was experienced by 70.7% of pts. Frequencies were as follows: infections (30.8%; COVID-19 infections 3.2%), arthralgia (10.8%), neutropenia (9.3%), fatigue (8.4%), diarrhea (7.7%), atrial fibrillation (7.4%; grade 3-4, 4.2%), fever (7.1%), rash (6.4%), anemia (6.1%) and hypertension (4.2%). Mild bleeding TEAEs were reported in 16.1% of pts with no major bleeding event. TEAEs were more frequent in the elderly (≥65 yrs) while no significant differences in the rate of TEAEs were recorded in TN and R/R pts (69.7% vs 71.4%, respectively). Serious TEAEs were reported in 21.9% of pts. Overall in intention to treat (ITT), 32 deaths (10%) were observed (TN=8, R/R=24). The most common causes of death were infections (3.5%) and progressive disease (PD) (1.9%). Permanent discontinuation was observed in 56 (18%) of the pts (TN=17.2%, R/R=18.7%) and it mostly occurred within the first 6 months. Main causes of discontinuation were toxicity (6.1%), PD (3.8%) or death (3.5%). Temporary interruptions (≤ 3 months without therapy and/or dose modifications) during the whole observation period occurred in 30.3% (TN=35.3%, R/R=27.2%) and 37.7% (TN=37.5%, R/R=37.8%) of pts, respectively, mainly determined by toxicity and clinical judgment. Finally, in this first IA after 17.3 months (range 1.1 - 27.0) median follow-up, the ibrutinib retention rate (calculated as the ratio between the number of patients who retained ibrutinib treatment over the total number of patients at risk) at 1-year was 81.9% [95% confidence interval (CI), 77.2% - 86.1%] with no difference between TN 83.2% (95% CI, 75.2% - 89.4%) and R/R 81.2% pts (95% CI, 74.9% - 86.4%). Conclusions EVIDENCE is the first real-world study of ibrutinib use in CLL clinical practice in Italy. Ibrutinib retention rate at one-year suggests a better knowledge and expertise of hematologists in the management of ibrutinib-related toxicities that may result in an improved long-term outcome of pts with CLL. Disclosures Molica: Janssen: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria; Astrazeneca: Honoraria. Scarfo: Astra Zeneca: Honoraria; Abbvie: Honoraria; Janssen: Honoraria, Other: Travel grants. Murru: Abbvie: Consultancy, Honoraria, Other: travel and accommodation; Janssen: Consultancy, Honoraria. Sportoletti: AstraZeneca: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria. Frigeri: Celgene: Consultancy, Speakers Bureau; Abbvie: Speakers Bureau; Janssen: Consultancy, Speakers Bureau; Amgen: Speakers Bureau. Sanna: Janssen: Consultancy; Abbvie: Consultancy; Astra Zeneca: Consultancy. Coscia: Janssen: Honoraria, Other, Research Funding; AbbVie: Honoraria, Other; AstraZeneca: Honoraria; Gilead: Honoraria. Reda: Abbvie: Consultancy; Astra Zeneca: Consultancy; Beigene: Consultancy; Janssen: Consultancy. Tafuri: Novartis: Research Funding; Roche: Research Funding; Celgene: Research Funding. Grugnetti: Janssen: Current Employment. Magarotto: Janssen: Current Employment. Mauro: Tskeda: Consultancy, Honoraria; Gilead: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Speakers Bureau; Abbvie: Consultancy, Honoraria, Speakers Bureau; Roche: Consultancy, Honoraria; Astra Zeneca: Consultancy, Honoraria, Speakers Bureau.

Introduction Although plenty of data exists on efficacy and safety of CLL drugs, their impact on patients' Health-Related Quality of Life (HRQoL) is largely unknown (1-2). Documentation of drug safety via traditional use of adverse events (AE) in hematology is limited if not complemented with Patient-Reported Outcomes (PRO) measures (3-4). Incorporation of HRQoL PROs is now essential to better evaluate risk-benefit of new therapeutic approaches and it is also highly valued by regulatory stakeholders (5). Most PRO data currently available for CLL patients (pts) came from randomized controlled trial settings (6-7), hence limiting generalizability of findings to CLL real-life patients. CHOICE study was designed to investigate CLL patients' QoL and preference towards different treatment profiles through a Discrete Choice Experiment (DCE) methodology in Italy. Due to the timelines of the study, which started in February 2020, the related data offer an insight into patients' perception and worries during the first wave of the COVID-19 pandemic. Methods This cross sectional, multi-center, observational study included CLL patients, treatment naïve during the watch & wait period (W&W) or already TREATED (around 50% each, controlled at site level), who signed the informed consent for study participation. Exclusion criteria were inability to take oral drugs, cognitive disorders that could impair the comprehension of the questionnaires and concomitant treatment for other malignancies. Patients were asked to fill in the following HRQoL questionnaires: EQ-5D-5L, EORTC QLQ-C30 and QLQ CLL-16, as well as a DCE questionnaire, (described elsewhere). Each questionnaire was completed by the patient on a tablet - using an App specifically developed for the study. Results 401 pts were enrolled in Italy in 16 hematology centers (Feb - July 2020); 199 W&W and 196 TREATED pts completed the questionnaires and were included in the evaluable population. Main patients' characteristics are shown in Table 1. 73.7% of TREATED pts were ON-treatment (30.8% were in 1st-line, 69,2% in further lines) and 26.3% were OFF-treatment; the majority of pts (55,6%) were currently treated with a target therapy (Table1). The EQ-5D-5L questionnaire showed no significant differences between groups. In both groups more than 80% of pts reported low values (1 or 2, indicating no or small impact) on all items. Median VAS was 75 for the TREATED group and 80 for the W&W group (0-100; higher scores indicate higher QoL). QLQ C-30 / CLL-16 scores had very similar results between TREATED and W&W pts suggesting a limited impact of CLL on pts QoL. The median (IQR) QoL Scale was 83.3 (67- 83) for TREATED and 83.3 (67- 92) for W&W pts (0-100; all functional scales had high scores, that represent a better level of functioning; all symptoms' scales had low values, representing a less important symptomatology or problem, Figure 1). The main symptoms reported were fatigue, insomnia, pain, and dyspnea, while the main worry was for "future health" (Figure 1). Distribution of data was statistically different between the 2 groups only for the Role functioning Scale (p=0.024) and the Social Functioning Scale (p=0.003) of QLQ-C30 and for the Infection Scale (p Conclusions CHOICE study helps to understand the CLL patients' mindset and feeling in the light of the COVID-19 pandemic impact on health care for this category of pts, highlighting their preferences and worries in a large cohort of pts in Italy, allowing a comparison between TREATED and W&W pts. The main limitation of the study was its cross-sectional design, which does not allow us to evaluate any change in QoL neither with respect to the impact of the pandemic, nor to the effects of the treatment, if any. CLL pts showed a good QoL, as confirmed by both EQ-5D-5L and EORTC QLQ C-30 / CLL-16 scores, with very similar results between TREATED and W&W pts (although slightly better results in the W&W vs TREATED group). The results of the present study are consistent with previous reports, and fatigue was the most reported symptom, while worry for future health was the most relevant score in CLL-16 questionnaire. Hospital accesses reduction that was detected during the pandemic might have influenced patients' response, as well as the extreme attention towards the danger of infections, and might have impacted patients' perception on future health. Figure 1 Figure 1. Disclosures Tedeschi: Beigene: Honoraria, Speakers Bureau; AstraZeneca: Honoraria, Speakers Bureau; AbbVie: Honoraria, Speakers Bureau; Janssen: Honoraria, Speakers Bureau. Gozzetti: Janssen: Honoraria; AbbVie: Honoraria. Reda: Beigene: Consultancy; Astra Zeneca: Consultancy; Abbvie: Consultancy; Janssen: Consultancy. Gualberti: AbbVie: Current Employment. Malgieri: AbbVie: Current Employment. Finsinger: AbbVie: Current Employment.

Venetoclax is the first BCL-2 inhibitor approved for the treatment of patients with chronic lymphocytic leukemia (CLL) alone or in combination with anti-CD20 monoclonal antibodies (MoAbs). Initial studies have shown high efficacy of venetoclax monotherapy or in combination with rituximab with an overall response rate of 79-92% in patients with relapsed/refractory (R/R) CLL. To investigate the use of venetoclax combinations in a real-world population, we designed this observational retrospective and prospective study aimed at defining the outcome of patients with R/R CLL treated with venetoclax-based regimens outside clinical trials in Italy. Efficacy (progression-free survival -PFS-, overall response rate -ORR-, complete response -CR-, measurable residual disease -MRD-) and safety (most frequent adverse events -AE-, grade 3-4 AE, laboratory and clinical tumor lysis syndrome -TLS-) data were collected within the study through a web-based platform after patients signed written informed consent. As of July 8 th, 2021 124 subjects (85 males, 39 females) were enrolled into the study (Table 1). Median age at venetoclax initiation was 70 years (44-91), median CIRS score 4 (0-14), median creatinine clearance 70 ml/min (22-123). A relevant proportion of patients presented adverse prognostic features, including TP53 aberrations [32% TP53 mutation and/or del(17p)], unmutated IGHV (77%). At the time of venetoclax initiation, patients had received a median of 2 previous therapies (1-8), with 57% previously exposed to BTK and/or PI3K inhibitors. 67/117 (57%) patients received venetoclax alone, while 50 were treated with a combination of venetoclax + rituximab (VenR), information on treatment plan was missing in 7 patients. Patients on venetoclax monotherapy compared to those receiving VenR showed a higher percentage of elevated LDH at baseline (64% vs 38%), were more heavily pretreated (median lines of therapy 3 vs 1), and had more frequently received treatment with ibrutinib (66% vs 27%) and/or idelalisib + rituximab (29% vs 4%). After a median follow-up of 13.7 months (0-41.9), the estimated 12m-PFS was 82% (CI 74-90%) (Figure 1), and the estimated 12m-overall survival (OS) was 83% (CI 76-91%). The best ORR in the whole cohort was 85% (CI 95% 76-91%) with a CR rate of 40%; best response was reached after a median of 3.9 months of treatment (range 0.6-30.5). The best ORR was not different in patients receiving VenR vs venetoclax alone (83% vs 88% respectively, p = n.s.), while the CR rate was significantly higher in those receiving VenR vs venetoclax alone (57% vs 30%, p=0.011). The ORR and CR rate in patients previously exposed to BTK and/or PI3K inhibitors were significantly lower (77% and 29% respectively), and the 12m-PFS was shorter in patients previously treated with ibrutinib compared to ibrutinib-naïve (75% vs 89%, p=0.005). Twenty subjects discontinued venetoclax (median time to discontinuation 4.1 months, range 0.4-10.8), 8 due to disease progression, 3 Richter's transformation, 7 AEs, 1 was lost to follow-up and 1 underwent planned allogeneic stem cell transplantation. Venetoclax-based regimens were well tolerated, with the most frequent AE of any grade related to venetoclax being neutropenia (79.6%), grade 3-4 in 61.9% (Table 2). In the whole cohort one grade 3 clinical TLS occurred and resolved without sequelae, and only 2/124 patients experienced laboratory TLS during ramp-up phase (both grade 1). No treatment-related death was reported. In conclusion, this analysis presents the results of one of the largest cohort of patients with R/R CLL treated with venetoclax-based regimens outside clinical trials and confirms the favourable efficacy and safety profile of the drug. In this patient population highly enriched for unfavorable disease features (1 out of 3 carrying TP53 aberrations, almost 80% with unmutated IGHV) venetoclax-based regimens were able to obtain a response in a high proportion of cases, with a very short time to best response (less than 4 months). As expected, response duration was shorter in patients previously exposed to BTKi/PI3Ki. When we compared the outcome of patients treated with venetoclax monotherapy vs VenR, the addition of anti-CD20 MoAb allowed to reach deeper responses by significantly increasing the CR rate. As the study and its data collection are still ongoing, the updated analysis of an expanded cohort with longer follow-up will be presented at the meeting. Figure 1 Figure 1. Disclosures Scarfo: Janssen: Honoraria, Other: Travel grants; Astra Zeneca: Honoraria; Abbvie: Honoraria. Quaglia: Roche: Other: Travel grants; Janssen: Honoraria, Other: Travel grants, Speakers Bureau; Sandoz: Consultancy; AstraZeneca: Honoraria. Marasca: AbbVie: Honoraria, Other: Travel grants; AstraZeneca: Honoraria; Janssen: Honoraria, Other: Travel grants. Sanna: Astra Zeneca: Consultancy; Abbvie: Consultancy; Janssen: Consultancy. Murru: Abbvie: Consultancy, Honoraria, Other: travel and accommodation; Janssen: Consultancy, Honoraria. Laurenti: Roche: Honoraria, Research Funding; AbbVie: Consultancy, Honoraria, Research Funding; AstraZeneca: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Gilead: Honoraria; BeiGene: Honoraria. Gaidano: Incyte: Membership on an entity's Board of Directors or advisory committees; Beigene: Membership on an entity's Board of Directors or advisory committees; Astrazeneca: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Reda: Beigene: Consultancy; Astra Zeneca: Consultancy; Abbvie: Consultancy; Janssen: Consultancy. Molica: Astrazeneca: Honoraria; Abbvie: Consultancy, Honoraria; Janssen: Consultancy, Honoraria. Sportoletti: AbbVie: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; AstraZeneca: Consultancy, Honoraria. Galimberti: AbbVie, Janssen: Honoraria, Other: Travel grants; Incyte: Speakers Bureau. Mauro: AbbVie: Consultancy, Speakers Bureau; AstraZeneca: Consultancy, Speakers Bureau; Janssen: Consultancy, Speakers Bureau; Roche: Consultancy, Speakers Bureau; Gilead: Consultancy, Research Funding, Speakers Bureau; Takeda: Consultancy, Speakers Bureau. Cuneo: Janssen: Consultancy, Speakers Bureau; AstraZeneca: Consultancy, Speakers Bureau; AbbVie: Consultancy, Speakers Bureau; Gilead: Consultancy, Speakers Bureau. Ghia: AstraZeneca: Consultancy, Honoraria, Research Funding; AbbVie: Consultancy, Honoraria, Research Funding; Acerta/AstraZeneca: Consultancy, Honoraria, Research Funding; Roche: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Research Funding; Gilead: Consultancy, Research Funding; BeiGene: Consultancy, Honoraria; Celgene/Juno/BMS: Consultancy, Honoraria; ArQule/MSD: Consultancy, Honoraria; Sunesis: Research Funding.

Background The provision of effective and tolerable therapy in elderly and unfit patients is a clear priority in CLL. The BCL2 inhibitor venetoclax has shown remarkable efficacy in relapsed/refractory population and recently, in unfit untreated patients receiving a fixed duration schedule combined with obinutuzumab. Large retrospective real word experiences confirmed the efficacy and survival outcomes previously seen in trials. Although toxicity analysis including rates of tumor lysis syndrome (TLS), dose interruptions and discontinuations have been assessed in a recent cohort (Eyre et al. BJH 2020), the question of whether age and fitness may affect efficacy and survival on venetoclax treatment is still open. Methods This is a multicenter retrospective analysis evaluating 158 patiens in 14 Italian centers treated with venetoclax from February 2017 to May 2020. For each patient we analyzed the impact of age (6), major CIRS comorbidity (at least one organ with a CIRS score ≥3, CIRS3+), ECOG-PS (0-1 versus >1) and CCI ( The survival functions for the time-to-event variables were estimated by Kaplan-Meier method and the related strata compared using the log-rank test. Multivariate analyses were performed too using the Cox regression. Results Patients characteristics are shown in table 1. Median time of observation for the whole population was 11.9 months (2.1 - 40.2). Median months of venetoclax treatment were 9.4 (range 2.1 - 40.2). Overall, 111 (70.3%) patients are continuing with therapy. A total of 42 (26.6%) patients permanently discontinued venetoclax: 7 (4.4%) due to toxicity; 25 (15.8%) due to progressive disease and/or Richter Transformation; 16 (10.1%) for other reasons. Among 158 patients, 41 (25.9%) discontinued treatment for ≥7 days with a median of 8 days/patient interruption. At least one dose reduction episode occurred in 36 patients (22.8%) and in 21 (13.3%) venetoclax was permanently administered at a lower dosage. Concomitant medications were reported in 134 (84.8%) patients, 75 of whom took ≥4 drugs in addition to venetoclax. In 32 cases (20.3%) venetoclax was administered concomitantly with CYP3A4 inhibitors/inducers. Patients age did not influence tox-DTD and PDR as well as patients outcomes in terms of EFS PFS and OS. In the elderly CIRS > 6 significantly influenced PDR (p 0.012) but not tox-DTD. In younger patients CIRS >6 did not show effect on treatment management; CIRS3+ instead, led to higher rate of tox-DTD (p 0.044). Progression free survival, EFS and OS were not affected by CIRS3+ and CIRS>6 even when patients were stratified according to age. Patients with an ECOG >1 experienced more tox-DTD (P 0.003) and a significantly shorter PFS (p 1 was independently associated with shortened PFS. While baseline neutropenia and concomitant treatment with CYP3A4 inhibitors/inducers led to a significant PDR, the presence of a compromised renal function did not influence patients management. Conclusions To our knowledge this is the first analysis assessing whether age, ECOG-PS and comorbidities retain a predictive value with venetoclax and if number and types of concomitant medications may interfere on treatment outcome. Age, CIRS and CIRS3+ did not affect patients management and outcomes; however, ECOG was the only significant factor related to fitness independently influencing outcome at the multivariate analysis. Disclosures Coscia: Abbvie: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Shire: Honoraria, Membership on an entity's Board of Directors or advisory committees; Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees; Karyopharm Therapeutics: Research Funding. Ciolli:Abbvie: Research Funding; Janssen: Honoraria. Laurenti:Janssen: Honoraria; Gilead: Honoraria; AbbVie: Honoraria; Roche: Honoraria. Sportoletti:AbbVie: Honoraria; Janssen: Honoraria. Reda:Janssen: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees. Varettoni:Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Travel/accommodations/expenses; Roche: Consultancy, Membership on an entity's Board of Directors or advisory committees; AbbVie: Other: Travel/accommodations/expenses. Mauro:Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Astrazeneca: Membership on an entity's Board of Directors or advisory committees; Jannsen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Octopharma: Consultancy; Shire-Takeda: Membership on an entity's Board of Directors or advisory committees. Murru:Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Gilead: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Vitale:Janssen: Honoraria. Montillo:Gilead: Honoraria, Speakers Bureau; Verastem: Honoraria; Astra Zeneca: Honoraria; Janssen: Honoraria, Speakers Bureau; AbbVie: Honoraria, Speakers Bureau; F. Hoffmann-La Roche: Honoraria, Research Funding. Tedeschi:Janssen: Honoraria, Speakers Bureau; Acerta: Honoraria, Speakers Bureau; Sunesis: Honoraria, Speakers Bureau; Beigene: Honoraria, Speakers Bureau; Abbvie: Honoraria, Speakers Bureau.

The treatment of chronic lymphocytic leukemia (CLL) has been radically changed in the last years thanks to the targeted therapies, including kinase (i.e. ibrutinib) and BCL2 (i.e. venetoclax) inhibitors. Venetoclax (VEN) in particular is able to obtain undetectable minimal residual disease (uMRD), though only in a proportion of patients (pts) when given as single agent, thus warranting the need of different strategies in those not achieving uMRD. We designed a phase 2 multicenter Italian study where ibrutinib (IBR) is added to VEN based on a MRD-driven strategy aiming at obtaining uMRD and discontinuing both treatments in pts who did not achieve uMRD with VEN mono. Study treatment started with VEN (ramp up to 400 mg/day as per current label) for 12 months. MRD status in peripheral blood (PB) and bone marrow (BM) was evaluated using the 6-color flow cytometry assay recommended by ERIC (CD5/CD81/CD79b/CD19/CD43/CD20). Pts with uMRD in both PB and BM at C12D1 discontinued VEN at C12D28 and entered the follow-up phase. Pts with detectable MRD in PB and/or BM added IBR 420 mg/day starting from C13D1 and continued both drugs up to maximum C24D28, uMRD, progression or unacceptable toxicity (whichever occurs first). After C24D28, pts with detectable MRD and still in response continued IBR alone. The primary endpoint was uMRD4 ( Thirty-eight pts (recruited from Nov 2017 to Jul 2018) fulfilled eligibility and started VEN. Baseline characteristics included: median number of prior therapies 1 (range 1-4) (60.6% previously treated with FCR or FC); del(17p) in 8/33 (24%); TP53 mutations in 10/30 (33%), and unmutated IGHV in 24/30 (80%). At the data cut-off, 35/38 evaluable pts still in the study have reached C24D1, 1 pt discontinued treatment due to myelodisplasia (considered unrelated to study treatment) before C12D1 and 1 pt progressed on VEN monotherapy shortly before that timepoint, 1 evaluation is still missing due to COVID-19 restrictions. At C12D1, uMRD4 in PB was achieved in 19/38 (50%) pts (Figure 1), 17/19 (89.5%) had uMRD4 confirmed in BM. Overall response rate with VEN single-agent was 36/38 (94.7%), 9 CR and 27 PR. As per protocol, the 17 pts (45%) with uMRD4 in PB and BM at C12D1 discontinued VEN at C12D28. Nineteen responsive cases with detectable MRD at C12D1 added IBR to VEN starting from C13D1. The combination of IBR and VEN led to an improved reduction of the depth of MRD in all but 3 pts with 16/19 (84%) achieving uMRD4 in both PB and BM between C16D1 (first MRD assessment after starting IBR) and C24D1, thus stopping both therapies as per protocol. After a median follow-up of 25.4 months (range 6.1-33.5) from treatment initiation, no clinical progression was observed among those discontinuing treatment in uMRD, while MRD4 relapse occurred in 21/33. Median time to MRD4 relapse in those who achieved uMRD at any timepoint and discontinued treatment was 4 months (range 2-13). Twelve pts (6 treated with VEN only) remain uMRD after stopping treatment, with a median observation of 13 months (range 3+-18+) since confirmed uMRD4. Safety data were analyzed in the intention-to-treat cohort (39 pts). No cases of clinical tumor lysis syndrome (TLS) and/or biochemical TLS were reported in the 39 pts exposed to VEN. Adverse events (AEs) were mild, with no treatment discontinuations or dose reductions. Five Serious AEs (Table 1) and 130 AEs (Table 2) occurred in 28 patients, without any SUSARs. All 5 SAEs were deemed unrelated to study drug(s) and 4/5 have resolved without sequelae. In conclusion, we here present the updated results of our study including the combination phase of VEN with IBR. This sequential MRD-guided approach was feasible and led to deeper responses in about 85% of pts not achieving uMRD4 after VEN alone. With this tailored and time-limited strategy 33 out of 38 pts (87%) obtained uMRD4 in PB and BM either after VEN monotherapy or the IBR-VEN combination, indicating we may reach identical depth of response with a personalized intensification and avoid unnecessary drug exposure. Time to clinical progression and response to VEN retreatment in this cohort remain to be established as well as the biological characteristics of those pts with persistent MRD despite the combined treatment. Updated results with further sequential MRD and clinical monitoring after treatment discontinuation will be presented at the meeting. Disclosures Scarfo: Gilead: Membership on an entity's Board of Directors or advisory committees; AstraZeneca: Honoraria; Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Farina:Abbvie: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees. Gaidano:Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Astrazeneca: Membership on an entity's Board of Directors or advisory committees; Sunesys: Membership on an entity's Board of Directors or advisory committees. Reda:Janssen: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees. Coscia:Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees; Shire: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Abbvie: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Karyopharm Therapeutics: Research Funding. Laurenti:Roche: Honoraria; Gilead: Honoraria; Janssen: Honoraria; AbbVie: Honoraria. Varettoni:Roche: Consultancy, Membership on an entity's Board of Directors or advisory committees; AbbVie: Other: Travel/accommodations/expenses; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Travel/accommodations/expenses. Ghia:Lilly: Consultancy, Honoraria; Sunesis: Consultancy, Honoraria, Research Funding; Adaptive, Dynamo: Consultancy, Honoraria; MEI: Consultancy, Honoraria; Celgene/Juno: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company), Research Funding; BeiGene: Consultancy, Honoraria; Acerta/AstraZeneca: Consultancy, Honoraria; ArQule: Consultancy, Honoraria; Gilead: Consultancy, Honoraria, Research Funding; AbbVie: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company), Research Funding; Novartis: Research Funding.

INTRODUCTION. Kinase inhibitors and glycoengineered monoclonal antibody, such as obinutuzumab (G), have significantly changed the treatment landscape of chronic lymphocytic leukemia (CLL). Both like the BTK inhibitor ibrutinib (IB) and obinutuzumab plus chlorambucil (G-CHL) are approved as first line therapy in CLL patients unfit for a fludarabine-base treatment. While IB has proved to be superior to bendamustine-rituximab in a phase 3 trial and an ongoing retrospective ERIC study, no head-to-head comparison has been done for IB vs G-CHL in a real-world evidence study. The aim of this study was to compared the clinical efficacy of the fixed duration G-CHL treatment vs continuous treatment with IB. METHODS. The inclusion criteria for this observational study were patients with a diagnosis of CLL, requiring treatment according to the iwCLL guideline (Hallek M, Blood 2018) and considered unfit for fludarabine-base therapy by the treating physician belonging to the Italian CLL campus. Patients received ibrutinib 420mg daily until progression or unacceptable toxicity, while G was administrated at 100mg on day 1, 900mg on day 2 and 1000mg on days 8 and 15 of the 1st cycle, then at 1000mg from cycles 2-6. Chlorambucil was administrated according to the local policy. An IGHV gene sequence homology ³98% was considered as unmutated (U-IGHV), as opposed to mutated (M-IGHV). TP53 disruptions (TP53dis) included deletions and mutations. Progression-free survival (PFS), time-to-next treatment (TTNT) and overall survival (OS) were calculated according to the iwCLL 2018 guideline. Minimal residual disease (MRD), assessed by flow cytometry, was considered undetectable when RESULTS. We recruited 284 CLL patients from 16 hematologic centers, 104 were treated with G-CHL and 180 with IB as first-line treatment. Once TP53dis cases were excluded, 102 patients treated with G-CHL and 80 treated with IB were included for further analysis. Among patients managed with G-CHL the median age was 75 years and 20% were older than 80 years, 47% had a CIRS≥6 (range 2-18), 68% had a clearance creatinine After a median follow-up of 21 months, 23 patients relapsed (20 G-CHL, 3 IB), 16 required a subsequent treatment (14 G-CHL, 2 IB) and 17 died (10 G-CHL and 7 IB). Two patients in the IB arm developed Richter syndrome. After 8 months from the start of treatment, the overall response rates in the G-CHL and IB arms were 86% vs 77% (p=0.1480), including 25% vs 6% complete remissions (CR, p=0.0013) and 61% vs 71% partial responses (PR, p=0.6320). Remarkably, an uMRD4 by flow-cytometry was documented in 42% and 9% of G-CHL patients in the peripheral blood and bone marrow, respectively. The median PFS was 33 months for G-CHL arm, but not reached for IB patients. The 24months PFS, TTNT and OS was 67% vs 91% (p=0.0012), 83% vs 97% (p=0.0128) and 89% vs 95% (p=0.5314) for the G-CHL and IB arms, respectively. Interestingly, the depth of response influenced PFS only in the G-CHL arm both in terms of clinical response (the median PFS was 8, 29 and 38 months for no responding, PR and CR patients) and MRD status (the 24 months PFS was 82% vs 50% and 100% vs 58% for uMRD4 vs MRD+ evaluated on peripheral blood and bone marrow). While the PFS was significantly better with IB than with G-CHL in U-IGHV (p=0.007), it was superimposable for M-IGHV patients (p=0.1946). Dose reductions or discontinuations were recorded in 39% and 44% of patients in the G-CHL and IB arms. Atrial fibrillation and infections occurred in 2% and 6% (p=0.0442), and in 25% and 17% (p=0.1455) of patients in the G-CHL and IB arms, respectively. CONCLUSIONS. The Italian experience with G-CHL confirms the marked efficacy and safety of this combination, in particular for patients who reach a CR and/or an uMRD4. The continuous treatment with ibrutinib provides a better disease management in CLL patients unfit for fludarabine-base therapy, but some on them - particularly those with a M-IGHV status - can achieve a long-term disease control with a fixed duration obinutuzumab-based chemoimmunotherapy. Disclosures Visentin: Janssen: Honoraria; Gilead: Honoraria; Abbvie: Honoraria. Mauro:Takeda: Membership on an entity's Board of Directors or advisory committees; Octopharma: Consultancy; Astrazeneca: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Jannsen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Vitale:Janssen: Honoraria. Ciolli:Janssen: Honoraria; Abbvie: Research Funding. Sportoletti:Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Rigolin:Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Gilead: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Abbvie: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Murru:Gilead: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Gozzetti:Janssen: Honoraria, Research Funding; Takeda: Honoraria; Amgen: Honoraria. Molica:Roche: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Gilead: Membership on an entity's Board of Directors or advisory committees. Marchetti:Pfizer: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees. Scarfo:Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Gilead: Membership on an entity's Board of Directors or advisory committees; AstraZeneca: Honoraria. Reda:Gilead: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees. Coscia:Karyopharm Therapeutics: Research Funding; Shire: Honoraria, Membership on an entity's Board of Directors or advisory committees; Gilead: 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, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Laurenti:Gilead: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; AbbVie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Roche: Membership on an entity's Board of Directors or advisory committees. Pizzolo:Abbvie: Speakers Bureau; janssen: Speakers Bureau. Semenzato:Takeda: Honoraria; Roche: Honoraria; Abbvie: Honoraria. Foà:Novartis: Speakers Bureau; Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Roche: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Incyte: Speakers Bureau; Roche: Membership on an entity's Board of Directors or advisory committees. Cuneo:Gilead: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Trentin:Shire: Honoraria; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Abbvie: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Octapharma: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees.

Background Chronic lymphocytic leukemia (CLL) is a disease of the elderly. Advancing age is associated with greater vulnerability, increasing treatment side effects and reduced survival with chemoimmunotherapy (CIT). Comorbidities burden, Charlson Comorbidity Index (CCI) and Cumulative Illness Rating Scale (CIRS) scores emerged as reliable tools in trials with patients (pts) receiving CIT. Ibrutinib changed CLL treatment paradigm. Nevertheless, adverse events leading to dose reductions and discontinuations are frequent in everyday practice. Finally, it is still unclear whether age, ECOG and comorbidities retain a predictive value with ibrutinib and if number and types of concomitant medications may interfere with treatment outcome. Methods This multicenter retrospective analysis evaluated 712 pts in 15 Italian centers treated with ibrutinib from March 2014 to May 2020. We analyzed the impact of age (6), major CIRS comorbidity (at least one organ with a CIRS score ≥3, CIRS3+), ECOG (0-1 vs >1) and CCI ( Survival functions for the time-to-event variables were estimated by Kaplan-Meier method and related strata compared using the log-rank test. Multivariate analyses were also performed using the Cox regression. Results Table 1 shows pts characteristics. Median follow-up was 26.6 months (range 3 - 75.8); median months on ibrutinib, 21.2 (range 3 - 75.4). Overall, 440 (61.8%) pts are continuing treatment. A total of 272 pts (38.2%) permanently discontinued ibrutinib: 128 (18%) due to toxicity; 132 (18.5%) due to progressive disease/Richter Transformation; 13 (1.8%) for other reasons. Of 712 pts, 325 (45.6%) discontinued treatment for ≥7 days with a median of 15 days/pts interruption. At least one dose reduction occurred in 219 pts (30.8%) and in 123 (17.3%) ibrutinib was permanently administered at a lower dosage. Toxicity was the main reason for PDR (175 pts). Concomitant medications were recorded in 624 (87.6%) pts, 374 of whom took ≥4 drugs in addition to ibrutinib. In 75 cases ibrutinib was concomitant with CYP3A4 inhibitors/inducers. At univariate analysis age ≥ 65y, CIRS>6, CIRS3+, ECOG >1 and CCI ≥2, showed to be significant for tox-DTD. All parameters except age ≥ 65y had an impact on PDR. ECOG >1 was the only parameter affecting PFS, EFS and OS (p6 negatively influenced PFS and EFS but not OS. In pts stratification according to age, only in the elderly CIRS >6 was significant for tox-DTD (p 0.009), PDR (p1 and CIRS>6 were the only fitness-related parameters affecting both PFS and EFS; the influence of ECOG was significant for tox-DTD and OS also (Table 2). CCI ≥2 had an impact on PDR only. Baseline neutropenia also influenced pts tox-DTD and all survival outcomes. Treatment with CYP3A4 inhibitors/inducers was independently associated with higher PDR. Pts outcome in terms of EFS, PFS and OS was also significantly dependent on number of previous lines of treatment (0 vs 1-2 vs ≥3) and presence of del17p/TP53 mutation (not shown in table 2). Ibrutinib PDR did not affect PFS and OS, while OS was significantly reduced in pts definitively discontinuing treatment due to toxicity (p Conclusions To our knowledge this is the largest series analyzing the role of age, comorbidities and concomitant medications in pts treated with ibrutinib. In univariate analysis the incidence of tox-DTD and PDR was significantly higher in pts with CIRS3+ and in elderly pts with CIRS>6. ECOG>1 significantly affected pts outcome. Furthermore, CIRS>6 was associated with shorter EFS and PFS in elderly. In the Cox regression hazards model ECOG and CIRS>6 were the only fitness-related factors influencing outcome. Baseline neutropenia also emerged as a parameter significantly affecting both treatment management and survival outcomes. Disclosures Tedeschi: Abbvie: Honoraria, Speakers Bureau; Acerta: Honoraria, Speakers Bureau; Janssen: Honoraria, Speakers Bureau; Beigene: Honoraria, Speakers Bureau; Sunesis: Honoraria, Speakers Bureau. Coscia:Karyopharm Therapeutics: Research Funding; Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees; Shire: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Abbvie: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Ciolli:Abbvie: Research Funding; Janssen: Honoraria. Reda:Abbvie: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees. Laurenti:Janssen: Honoraria; Gilead: Honoraria; AbbVie: Honoraria; Roche: Honoraria. Varettoni:Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Travel/accommodations/expenses; Roche: Consultancy, Membership on an entity's Board of Directors or advisory committees; AbbVie: Other: Travel/accommodations/expenses. Murru:Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Gilead: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Sportoletti:AbbVie: Honoraria; Janssen: Honoraria. Vitale:Janssen: Honoraria. Di Raimondo:Takeda: Consultancy, Honoraria; GSK: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Amgen, Takeda, Novartis: Honoraria; GILEAD, Incyte: Research Funding. Montillo:F. Hoffmann-La Roche: Honoraria, Research Funding; AbbVie: Honoraria, Speakers Bureau; Janssen: Honoraria, Speakers Bureau; Astra Zeneca: Honoraria; Gilead: Honoraria, Speakers Bureau; Verastem: Honoraria.

The CLL-IPI score, which combines genetic, biochemical, and clinical parameters, represents a simple worldwide model able to refine risk stratification for CLL patients. This score, developed in the era of chemo-immunotherapy, has not been gauged extensively in R/R-CLL patients treated with novel targeted agents, such as BCR and BCL2 inhibitors. Soumerai et al (Lancet Hematol 2019) assembled a novel risk model for OS in the setting of R/R-CLL receiving targeted therapies in clinical trials. This model, consisting of four accessible markers (β2M, LDH, Hb, and time from initiation of last therapy; BALL score), is able to cluster 3 groups of CLL patients with significantly different OS. This multicenter, observational retrospective study aimed to validate the proposed Soumerai (BALL) and/or CLL-IPI scores for R/R-CLL real-world patients treated with idelalisib and rituximab (IDELA-R). The primary objectives were to determine whether: i) the CLL-IPI retains its prognostic power also in R/R patients treated with IDELA-R; ii) the BALL score is of prognostic value for IDELA-treated R/R-CLL patients, and iii) the BALL score is predictive of PFS. This study, sponsored by Gilead (ISR#IN-IT-312-5339), included CLL patients collected from 12 Italian centers, who received IDELA-R (idelalisib 150 mg b.i.d. and a total of 8 rituximab infusions intravenously) outside clinical trials as salvage therapy with available data for the calculation of the CLL-IPI and BALL scores at the time of treatment start. OS was estimated for all subgroups of both scores. Additionally, risk-specific PFS was assessed. Kaplan-Meier curve, log-rank test, and Cox regression analyses were performed. The prognostic accuracy of the predictive model was assessed by Harrell's C-index. Overall, 120 CLL patients were included in this analysis. The majority of patients were Binet stage B and C (94.2%). The median age was 75 years and 83 cases (69.2%) were male. The median number of previous therapies was 3 (range 1-9) Baseline patient features are listed in Table 1. After a median follow-up of 1.6 years (1 month to 5.8 years), 33 patients had died and 39 experienced an event (death or progression). CLL-IPI scoring (115/120 evaluable cases) indicated that 6 patients (5.2%) were classified as low-risk, 24 (20.9%) as intermediate-risk, 58 (50.4%) as high-risk, and 27 (23.5%) as very high-risk. Stratification of patients according to the CLL-IPI score did not allow prediction of significant differences in OS. Thus, low-risk patients had a 2-year OS probability of 75% (HR=1), with an intermediate-risk of 68% (HR=2.9, 95%CI 0.37-23.3, P=0.3), high-risk of 83% (HR=1.58, 95%CI 0.2-12.5, P=0.66), and very high-risk of 63% (HR=5.9, 95%CI 0.78-45.2, P=0.86). Next, we tested a modified CLL-IPI by assigning a more balanced score to the original CLL-IPI variables (Soumerai et al, Leukemia Lymphoma 2019), partially overlapping previous results. Specifically, modified CLL-IPI high-risk group showed a significantly different OS as compared with intermediate- and low-risk groups. However, differently from the original report no difference was observed between low- and intermediate-risk). According to the BALL score (120/120 evaluable cases), 33 patients (27.5%) were classified as low-risk, 68 (56.7%) as intermediate-risk, and 19 (15.8%) as high-risk. Stratification of patients according to the BALL score predicted significant differences in terms of OS. Thus, low-risk patients had a 2-year OS probability of 92% (HR=1), intermediate-risk of 76% (HR=5.47, 95%CI 1.3-23.7, P=0.023), and high-risk of 54% (HR=15.1, 95%CI 3.4-67, P Disclosures Mauro: Gilead: Consultancy, Research Funding; Jannsen: Consultancy, Research Funding; Shire: Consultancy, Research Funding; Abbvie: Consultancy, Research Funding; Roche: Consultancy, Research Funding. Coscia:Abbvie: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees; Karyopharm Therapeutics: Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding. Varettoni:ABBVIE: Other: travel expenses; Roche: Consultancy; Janssen: Consultancy; Gilead: Other: travel expenses. Rossi:Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Abbvie: Honoraria, Other: Scientific advisory board; Janseen: Honoraria, Other: Scientific advisory board; Roche: Honoraria, Other: Scientific advisory board; Astra Zeneca: Honoraria, Other: Scientific advisory board. Gaidano:AbbVie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Sunesys: Consultancy, Honoraria; Astra-Zeneca: Consultancy, Honoraria; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau.

Novel therapies targeting BTK (ibrutinib), PI3Kδ (idelalisib) and BCL2 (venetoclax) are active in poor-risk chronic lymphocytic leukemia (CLL) and are widely administered to patients with relapsed/refractory (R/R)-CLL. Given the activity of ibrutinib in high-risk CLL patients, including those with del17p/TP53 mutation or germline IGHV genes, we assumed that this drug could diminish the prognostic utility of the CLL-IPI, because the outcome of patients with high- and very high-risk CLL-IPI scores may improve. Recently, Soumerai et al (Lancet Hematology, 2019) proposed a new risk score for overall survival (OS) based on four accessible markers, called BALL (β2-microglobulin, anemia, LDH, last therapy), in the setting of R/R-CLL patients receiving chemo-immunotherapy or targeted therapies in clinical trials. This model segregates CLL patients into three groups with significantly different OS. This multicenter, observational retrospective study aimed at validating the proposed BALL score for R/R-CLL real-world patients treated with ibrutinib. The primary objectives were to determine whether: i) the BALL score is of prognostic value for ibrutinib R/R-CLL patients, ii) the BALL score is predictive of progression-free survival (PFS); and iii) the CLL-IPI retains its prognostic power also in R/R patients treated with ibrutinib. This study, from an institutional Italian multicenter working group on CLL ('Campus CLL'), included CLL patients collected from 18 Italian centers and 1 Israeli center, who received ibrutinib 420 mg/day outside of clinical trials as salvage therapy with available data for the calculation of the BALL and CLL-IPI scores at the time of the start of treatment. OS was estimated for all subgroups according to both scores. Additionally, risk-specific PFS was assessed. Kaplan-Meier curve, log-rank test and Cox regression analyses were performed. The prognostic accuracy of the predictive model was assessed by the Harrell's C-index. Overall, 541 CLL patients were included in this analysis. The majority of patients were Binet stages B and C (87.2%). The median age was 70.4 years (range 37 - 88) and 353 cases (65.2%) were male. The median number of previous therapies was 2 (range 1-9). The baseline patients' features are listed in Table 1. After a median follow-up of 1.8 years (range 1 month to 5.8 years), 101 patients had died and 206 experienced an event (death or progression). According to the BALL score, 372 patients (68.8%) were classified as low-risk, 132 (24.4%) as intermediate-risk and 37 (6.8%) as high-risk. Stratification of patients according to the BALL score predicted significant differences in terms of OS. Thus, low-risk patients had a 2-year OS probability of 89.2% (HR=1), intermediate-risk of 79.9% (HR=2.8, 95%CI 1.8-4.4, P Our multicenter retrospective study confirms the prognostic power of the BALL score in this real-world series of R/R-CLL patients treated with ibrutinib, as previously reported in the setting of clinical trials (Soumerai et al, Lancet Hematology 2019). Furthermore, the CLL-IPI did not retain a discriminative power in the current retrospective study of ibrutinib-treated patients, possibly due to i) the well-known activity of ibrutinib in high-risk CLL patients, i.e. those with TP53 disruption and/or germline IGHV genes, which represent the most heavily weighted adverse risk factors contributing to the CLL-IPI, and to ii) the fact that the CLL-IPI was designed for patients receiving front-line chemo-immunotherapy. Conversely, the BALL score may identify higher risk R/R-CLL patients potentially requiring alternative and more effective therapeutic strategies. Disclosures Mauro: Jannsen: Consultancy, Research Funding; Gilead: Consultancy, Research Funding; Abbvie: Consultancy, Research Funding; Shire: Consultancy, Research Funding; Roche: Consultancy, Research Funding. Coscia:Gilead: Membership on an entity's Board of Directors or advisory committees; Karyopharm Therapeutics: Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Abbvie: Membership on an entity's Board of Directors or advisory committees. Herishanu:Roche: Honoraria; Janssen: Honoraria; AbbVie: Honoraria. Varettoni:ABBVIE: Other: travel expenses; Roche: Consultancy; Gilead: Other: travel expenses; Janssen: Consultancy. Rigolin:AbbVie: Speakers Bureau; Gilead: Speakers Bureau; Gilead: Research Funding. Rossi:Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Abbvie: Honoraria, Other: Scientific advisory board; Janseen: Honoraria, Other: Scientific advisory board; Roche: Honoraria, Other: Scientific advisory board; Astra Zeneca: Honoraria, Other: Scientific advisory board. Gaidano:AbbVie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Sunesys: Consultancy, Honoraria; Astra-Zeneca: Consultancy, Honoraria. Cuneo:Amgen: Honoraria; Abbvie: Honoraria, Speakers Bureau; Gilead: Honoraria, Speakers Bureau; Janssen: Honoraria, Speakers Bureau; Roche: Honoraria, Speakers Bureau. Foà:Roche: Consultancy, Speakers Bureau; Celltrion: Membership on an entity's Board of Directors or advisory committees; Abbvie: Consultancy, Speakers Bureau; Amgen Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Amgen Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Incyte: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Shire: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Incyte: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Roche: Consultancy, Speakers Bureau; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Pfizer: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Shire: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Pfizer: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Abbvie: Consultancy, Speakers Bureau; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celltrion: Membership on an entity's Board of Directors or advisory committees.

Background: Elderly patients with acute myeloid leukemia (AML) experience a low complete remission (CR) rate following intensive chemotherapy, a short duration of CR and high treatment-related mortality. Median survival is 7-12 months. Several reports suggest that maintenance therapy may improve survival. In particular, a recent report (Huls G, et al. Blood 2019) has shown that azacitidine (Aza) maintenance treatment improves 1-year disease-free survival (DFS) when adjusted for cytogenetics at diagnosis and platelet (PLT) count at randomization. Aims: This phase III, randomized, multicenter trial assesses the efficacy of post-remission Aza treatment versus best supportive care (BSC) in 54 AML subjects >60 years of age in CR after homogeneous induction and consolidation chemotherapy. Primary endpoint is the difference in DFS at 2 and 5 years between arms; main secondary endpoints are the difference in overall survival (OS), the number and length of hospitalizations and quality of life (QoL). Methods: AML subjects with >30% blasts, "de novo" or evolving from myelodysplastic syndrome and fit for intensive chemotherapy, received 2 courses of "3+7" therapy (daunorubicin 40 mg/m2 daily days 1-3 and cytarabine 100 mg/m2 daily IV infusion days 1-7). Subjects obtaining a CR received cytarabine 800 mg/m2 3 hour infusion bid days 1-3 and were randomized 1:1 to receive BSC or Aza at 50 mg/m2 s.c./i.v. for 7 days every 28 days and dose increase after 1st cycle to 75 mg/ m2 for further 5 cycles, followed by cycles every 56 days for 4.5 years or until relapse. QoL was assessed by QOL-E and EORTC QLQ-C30. Results: 149 subjects were included of median age 69, interquartile range (IQR) 65-74 years, and male/female 78/71. Amongst subjects not reaching randomization, 59 were relapsed/refractory, 22 died, 10 refused to continue, 3 were excluded for protocol violation, and 1 was lost to follow-up. Randomized patients (27 Aza, 27 BSC) were in study until relapse. Median follow-up was 9.9 months (IQR: 3.2-22.5). At 2 years post-randomization, no deaths occurred and 21 subjects in the BSC arm (median DFS 9 months, 95% CI 0-20) relapsed versus 18 subjects in the Aza arm (median DFS 11 months, 95% CI 1-21; P=0.33; Fig.1a). There was an effect modification by age on the effect of Aza versus BSC on relapse (P for effect modification=0.02) so that the effect of AZA was not significant for subjects 73 years (P=0.008, Fig.1b). Cytogenetic risk (P=0.84), minimal residual disease (P=0.97), and platelet (PLT) count (below/above 100 Gi/L, P=0.47) did not modify the effect of Aza on DFS. However, cytogenetic risk and PLT count were confounders: after data adjustment, the effect of Aza on DFS just failed to reach statistical significance [HR (Aza vs BSC): 0.53, 95% CI: 0.26-1.05, P=0.068] . At 5 years post-randomization, no subjects died; 2 subjects on Aza and 1 subject on BSC withdrew consent and 1 subject on Aza in CR withdrew for relapse of bladder cancer. In the BSC arm, 23 subjects relapsed (median DFS 9 months, 95% CI: 0-20) versus 20 Aza subjects (median 11 months, 95% CI: 1-21; P=0.31, Fig.1a).Similar to 2 years post-randomization, at 5 years post-randomization an effect modification by age on the effect of Aza versus BSC was confirmed (P for effect modification=0.01) and the effect of Aza was significant only in subjects >73 years of age (P=0.007, Fig.1b). Again, data adjustment for cytogenetic risk and PLT count strengthened the link between Aza and DFS [HR: 0.56, 95% CI: 0.29-1.07, P=0.08]. Grade 3-4 adverse events (mainly neutropenia) were more frequent in the Aza (41%) than in the BSC arm (4%, P=0.002). Two Aza subjects were hospitalized twice for adverse events for a total of 22 and 26 days, respectively, versus no hospitalization for BSC subjects. QOL-E scores were poor at diagnosis and improved significantly at randomization, with further improvement for physical well-being. EORTC QLQ-C30 symptoms improved progressively over time. In linear mixed model analyses, no significant effect of Aza versus BSC was found for any QoL domain, confirming safety of Aza versus BSC. Summary/Conclusion: With the limitation of a small trial, we conclude that post-remission Aza in elderly AML patients receiving standard induction-consolidation chemotherapy is safe and is well-tolerated. Noteworthy, in patients over 73 years of age, Aza significantly prolongs DFS up to 5 years. Figure Disclosures Oliva: Celgene Corporation: Consultancy, Honoraria, Speakers Bureau; Apellis: Consultancy; Novartis: Consultancy, Speakers Bureau. Candoni:Merck SD: Honoraria, Speakers Bureau; Gilead: Honoraria, Speakers Bureau; Celgene: Honoraria; Pfizer: Honoraria; Janssen: Honoraria. Di Raimondo:Takeda: Consultancy; Amgen: Consultancy, Honoraria, Research Funding. Musto:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees. Mannina:Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees. Martino:Novartis: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees; Bristol myers squibb: Membership on an entity's Board of Directors or advisory committees. Alati:Novartis: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees.

Background Wnt/Fzd signaling is known to play a pervasive influence in hematopoietic stem cell maintenance, T-cell development in the thymus and function as well as an important role in T-cell acute lymphoblastic leukemia (T-ALL) establishment. We have previously described a recurrent rearrangement involving the WNT10Blocus (WNT10BR) expressing a transcript variant (WNT10BIVS1) in acute myeloid leukemia. To determine the occurrence of this rearrangement in T-ALL we analyzed retrospectively an italian cohort of patients (n=20) and detected the WNT10BRrearrangement with a high prevalence (14/20). We also confirmed the relevance of these findings to human disease, detecting the molecular circuit triggered by the WNT10B over-expression using the MOLT-4 T-ALL cell model.In this report, we examined the expression of components of the Wnt signaling cascade mediated by WNT10B and the effects of specific gene silencing by short hairpin RNA (shRNA) and exposure to the potent PORCN inhibitor (LGK974), or the TGFbRI inhibitor (A83-01) on the WNT10B-mediated Wnt signaling activation. Methods We used the T-ALL model MOLT-4 cell line to assess the WNT10B/FZD signaling axis driven by WNT10BR. In order to identify interaction between WNT10B and FZD receptors we performed in situ proximity ligation assay (PLA) a method used to visualize protein-protein interactions.MOLT4 cells were infected with WNT10B/WNT10BIVS1-shRNA silencing lentiviral vectors versus empty vector control and treated with increased concentration of LGK974 or A83-01, subsequently the effects of pharmacological inhibition on the WNT10B/FZD interactions and on Wnt effector proteins were evaluated by PLA and expression analyses. Cell proliferation and cell death were measured by EdU assay and Annexin-V/Propidium Iodide (PI) analyses. Results We found that WNT10BRdrives Wnt signaling activity in T-ALL through interaction of WNT10B with FZD6 receptor. The effects of WNT10B/FZD6 interaction on Wnt-mediated signal in MOLT-4 were interfered by short hairpin RNAs (shRNAs)-mediated gene silencing and by small molecules-mediated disruption of Wnt-dependent signaling. We performed WNT10BIVS1knockdown or pharmacological inhibition of WNT10B release by the porcupine (PORCN) inhibitor LGK974 and these in turn progressively down-modulate WNT10B/FZD6 protein complex formation and significantly impairs intracellular effectors and leukemic expansion. Finally, we induced interference to the WNT10B/FZD6 protein complex formation by exposure to the TGFbRI inhibitor A83-01 via inhibiting FZD6 expression, confirming its role in the WNT10B-mediated signaling activation. Conclusion Our study describes the molecular circuit of WNT10BR-mediated activation and highlight a strategy for a major improvement in T-ALL treatment.By altering FZD6-WNT10B complex formation, may provide the basis for therapeutic strategies to eradicate leukemic stem cells in patients selectively deployed depending on the underlying genetics of disease. Disclosures No relevant conflicts of interest to declare.

Introduction: Chronic Lymphocytic Leukemia (CLL) is a clinically and biologically heterogeneous disorder that can be associated with immunological dysregulation. Several prognostic factors, such as IGHV status and chromosomal aberrations as trisomy 12, del11q, del13q or del17p have been detected so far. More recent genetic mutations, such as BIRC3, SF3B1, NOTCH1 and TP53 stratify even further the prognosis and the outcome in CLL patients (pts). However all data above reported, because of expensive techniques and experience typical of big laboratories, are not available to all medical centers. Therefore we considered necessary to identify more accessible and easy to perform parameters in all laboratories, as data concerning the presence of hypogammaglobulinemia, IgM or IgG monoclonal gammopathy, whose prevalence and impact on natural history of CLL in the medical literature are controversial, contradictory and not very significant because of few numbers in cohorts. Therefore the first aim of the study was to evaluate the prevalence of monoclonal IgM/CLL, IgG/CLL and hypogammaglobulinemia compared with CLL pts with normal immunoglobulins (Ig) levels and to establish the impact on clinical outcomes based on Ig levels. The second aim was to find a correlation between each group of pts and biological data. Methods: From four different Italian centers, we collected data from 1505 pts diagnosed with typical CLL from 1987 to 2017 and we divided them in four groups based on the presence of qualitative and quantitative alterations of serum immunoglobulins. Baseline assessment and levels of serum Ig, immunofixation, chromosomal aberrations and clinical features were collected. [Table 1]. We evaluated the impact of each immunoglobulin subset on progression free survival (PFS) and overall survival (OS). Results: Once assessment was made, we included in our study 1505 pts. Median age of 65.5 was similar in all groups and data gathered from the four centers showed an overlapping rate about prevalence and time-dependent parameters in CLL pts and their related subclasses. The overall prevalence of monoclonal gammopathy was 15%, of whom 149 pts (10%) with IgG/CLL and 73 pts (5%) with IgM/CLL. Hypogammaglobulinemia was detected in 200 pts (13%), while 1083 pts (72%) had no evidence of paraprotein or hypogammaglobulinemia. The worst outcome group was identified among CLL with IgM paraprotein; moreover, this group of pts showed more advanced stages at diagnosis according to Binet staging (p To evaluate if the specific deficit of IgG or IgM could have any unfavourable impact on each group's prognosis, we measured the serum levels of IgM and IgG in all pts. No statistically significant differences were observed among time-dependent parameters in IgG/CLL, IgM/CLL and hypogamma groups, based on IgM and IgG levels, if deficient or normal.Finally, in the group of pts who had normal gamma-level, median PFS and TTT was reached at 79 months (p=0.006 and 0.002, respectively) in the subgroup with IgM deficiency, while no statistical difference was observed regarding OS (p=0.785). Conclusions: Our study provides data about prevalence and impact of monoclonal gammopathy and hypogammaglobulinemia on the outcomes of CLL patients. In this study, we observed that the 28% pts had any qualitative or quantitative immunoglobulins alteration, of whom 15% had monoclonal gammopathy and 13% had hypogammaglobulinemia. The worst outcomes were observed in the IgM/CLL pts in terms of PFS and OS. In conclusion, the laboratory data of serum Ig could be used as predictive markers of clinical outcomes because, for their easy availability, they could direct the prognosis of CLL pts. As a future perspective, we would like to characterize pts with monoclonal IgM component from a biological view, to correlate the subset of somatic mutations of the heavy chains of surface immunoglobulins with the monoclonal component and its prognostic significance. Disclosures Varettoni: ABBVIE: Other: travel expenses; Roche: Consultancy; Gilead: Other: travel expenses; Janssen: Consultancy. Trentin:ABBVIE: Honoraria, Other: board; Janssen: Consultancy, Honoraria, Other: Board; gilead: Consultancy; Roche: Honoraria, Other: Board.

Background: In myelodysplastic syndromes (MDS), thrombocytopenia is associated with mortality and treatments in this setting are scarce. We tested whether eltrombopag, a thrombopoietin receptor agonist, be effective in improving outcomes in lower-risk MDS with severe thrombocytopenia within a multicentre clinical trial (EQoL-MDS). Initial interim results of short-term efficacy and safety have been published (Oliva et al. Lancet Hem 2017) in the first 90 subjects. We present interim results of the second phase for long-term results in the initial 90 of 174 subjects. Methods: In a single-blind, randomised, controlled, phase 2 trial of adult patients with International Prognostic Scoring System (IPSS) low- or intermediate-1-risk MDS and severe thrombocytopenia. Adult patients with a stable platelet (PLT) count Results: The first 90 subjects were enrolled between 2011 and 2016. Characteristics of patients have been previously published (Lancet Hem 2017). PLT responses occurred in 28 (47.5%) of 59 patients in the eltrombopag group versus 1 (3.2%) of 31 patients in the placebo group (odds ratio 27.1 [95% CI 3.5-211.9], p=0.002) in median time 14 days (95% CI 7-40 days). Severe bleeding (WHO bleeding score ≥2) occurred in 19 patients, with a significantly higher incidence in the placebo (11 [35.3%] of 31 patients) than in the eltrombopag arm (8 [13.6%] of 59 patients; p=0.015). Sixty-eight grade 3-4 adverse events occurred in 30 of 59 (50.8%) eltrombopag patients versus 10 events in 6 of 31 placebo cases (19.4%;χ2=8,4, p=0.004, stopping rule not reached). The outcomes acute myeloid leukemia (AML) evolution, progression and death occurred in 5 (8.5%), 4 (6.8%), and 5 (8.5%), respectively of 59 eltrombopag cases versus 2 (6.5%), 3 (9.7%), 2 (6.5%), respectively of 31 placebo cases (P ranging from 0.69 to 1.00). Median LFS, combined outcome (AML, disease progression and death) and OS were not reached in the whole group. Differences in LFS, combined outcome and OS at 2 and 5 years by study arms were adjusted for baseline bone marrow blasts since the proportion of patients with >2% blasts (i.e. the median value of the whole study cohort) tended to be higher (P=0.06) in Eltrombopag (59.3%) than in placebo treated (38.7%) patients and resulted to be a strong predictor of study outcomes at both 2 and 5 years (P Conclusion. Eltrombopag is well-tolerated in patients with lower-risk MDS and severe thrombocytopenia and is clinically effective in raising PLT count and reducing bleeding events. QoL improves with response to treatment. The assessment of long-term safety and efficacy of eltrombopag and its effect on survival (phase 2 part of study) is still ongoing. Disclosures Oliva: Novartis: Consultancy, Speakers Bureau; Apellis: Consultancy; Celgene Corporation: Consultancy, Honoraria, Speakers Bureau. Alati:Pfizer: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees. Santini:Celgene Corporation: 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; Johnson & Johnson: Honoraria; Acceleron: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; Menarini: Membership on an entity's Board of Directors or advisory committees. Giai:Pfizer: Honoraria; BMS: Honoraria; Novartis: Honoraria. Balleari:Celgene: Membership on an entity's Board of Directors or advisory committees. Ferrero:Novartis: Honoraria. Germing:Novartis: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; Jazz Pharmaceuticals: Honoraria; Amgen: Honoraria. Fenaux:Aprea: Research Funding; Jazz: Honoraria, Research Funding; Celgene Corporation: Honoraria, Research Funding; Astex: Honoraria, Research Funding. Palumbo:Amgen: Honoraria; Celgene: Honoraria; Janssen: Honoraria; Novartis: Honoraria; Teva: Honoraria; Hospira: Honoraria. Liberati:Novartis: Other: Clinical trial support; Janssen: Honoraria; AbbVie: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Clinical trial support; Roche: Other: Clinical trial support; Amgen: Membership on an entity's Board of Directors or advisory committees, Other: Clinical trial support; Celgene: Honoraria, Other: Clinical trial support; Bristol-Myers Squibb: Honoraria; Takeda: Membership on an entity's Board of Directors or advisory committees; Servier: Honoraria, Membership on an entity's Board of Directors or advisory committees; Incyte: Consultancy. Molteni:Celgene: Membership on an entity's Board of Directors or advisory committees. Buccisano:Astellas: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Bocchia:Novartis: Honoraria; Incyte: Honoraria; BMS: Honoraria. Candoni:Merck SD: Honoraria, Speakers Bureau; Gilead: Honoraria, Speakers Bureau; Celgene: Honoraria; Pfizer: Honoraria; Janssen: Honoraria. Martino:Bristol myers squibb: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees. Latagliata:Janssen: Honoraria; Novartis: Honoraria; Pfizer: Honoraria; Celgene: Honoraria. OffLabel Disclosure: Eltrombopag is indicated for: 1. the treatment of patients aged 1 year and above with primary immunethrombocytopenia (ITP) lasting 6 months or longer from diagnosis and who are refractory to other treatments; 2. in adult patients with chronic hepatitis C virus (HCV) infection for the treatment of thrombocytopenia, where the degree of thrombocytopenia is the main factor preventing the initiation or limiting the ability to maintain optimal interferon-based therapy; 3. in adult patients with acquired severe aplastic anaemia who were either refractory to prior immunosuppressive therapy or heavily pretreated and are unsuitable for hematopoietic stem cell transplantation

Autoimmune cytopenias (AIC) affect 4-7% of patients with chronic lymphocytic leukemia (CLL). Targeted drugs (i.e. ibrutinib, idelalisib and venetoclax) have recently entered the therapeutic armamentarium for CLL showing excellent results in terms of efficacy. The activity of these compounds in CLL-associated AIC is largely unknown, due to the exclusion of patients with active AIC from the pivotal clinical trials and to the paucity of studies directly investigating the role of these novel inhibitors in this setting. Also, no guidelines are available to direct the management of patients who develop AIC during the treatment with targeted drugs. The purposes of this study were 1) to evaluate the characteristics and outcome of pre-existing AIC in patients with CLL treated with ibrutinib, idelalisib or venetoclax in the real-life setting, and 2) to describe the incidence, quality and management of treatment-emergent AIC during therapy with targeted drugs. We retrospectively collected data from patients with CLL treated with ibrutinib (n=379), idelalisib (n=100), or venetoclax (n=49) in 11 Italian centers. AIC status was defined as active when it was not controlled with current medical management, controlled/improved when blood counts did not reach the normal values or if subclinical hemolysis was still present, and resolved in the presence of a complete blood count normalization. Pre-existing AIC was reported in 38/379 (10%) of ibrutinib-treated patients, 20/100 (20%) of idelalisib-treated patients and 6/49 (12%) of patients who received venetoclax (Table 1). At the time of the start of ibrutinib, pre-existing AIC was considered active in 8/38 (21%) patients, controlled in 11/38 (29%) and resolved in 19/38 (50%). Among patients with active AIC, ibrutinib treatment induced AIC improvement in 1 patient and a resolution in 4. In addition, during ibrutinib treatment, in 1 patient active AIC was initially controlled but subsequently relapsed at CLL recurrence, in 1 patient concomitant steroid administration was required to maintain AIC controlled and in 1 patient AIC remained stable without needing additional therapy. Controlled AIC remained stable in 3 patients, improved in 3 and resolved in 5. Among 19 patients with a resolved AIC at the time of the start of ibrutinib, only 1 had an AIC relapse during ibrutinib therapy, which was successfully managed with steroids. At the time of the start of idelalisib, pre-existing AIC was considered active in 5/20 (25%) patients, controlled in 7/20 (35%) and resolved in 8/20 (40%). During idelalisib treatment, AIC improved in 2 patients with active AIC and in 1 patient with controlled AIC, and resolved in 2 patients with active AIC and in 5 patients with controlled AIC. No recurrence was observed in 7/8 patients who had resolved AIC at the time of the start of idelalisib. Overall, a recurrence or worsening of a pre-existing AIC occurred in 3/20 patients. In the venetoclax cohort, at treatment initiation, pre-existing AIC was active in 2/6 (33%) patients, controlled in 1/6 (17%) and resolved in 3/6 (50%). Active AIC resolved with venetoclax treatment in 1 patient and improved, albeit with concomitant steroid therapy, in the second. The patient with controlled AIC remained stable but needed additional AIC-directed therapy. AIC recurrence was observed in 1/3 patients with resolved AIC and was successfully treated with steroids. Regarding treatment-emergent AIC, they occurred in 8/379 (2%) patients during ibrutinib therapy, in 4/100 (4%) during idelalisib and in 7/49 (14%) during venetoclax (Table 1). Treatment-emergent AIC significantly correlated with pre-existing AIC in the three cohorts (p In conclusion, this study based on a large, multicenter, retrospective real-life analysis shows that 1) ibrutinib, idelalisib and venetoclax can induce an improvement or even a resolution of pre-existing AIC in CLL patients, and that 2) treatment-emergent AIC during targeted drugs administration is a rare event, which in most patients is manageable without requiring treatment interruption. Disclosures Trentin: ABBVIE: Honoraria, Other: board; Janssen: Consultancy, Honoraria, Other: Board; gilead: Consultancy; Roche: Honoraria, Other: Board. Tedeschi:Janssen spa: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Gilead: Consultancy; AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees; SUNESIS: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BeiGene: Honoraria; AstraZeneca: Membership on an entity's Board of Directors or advisory committees. Mauro:Roche: Consultancy, Research Funding; Jannsen: Consultancy, Research Funding; Shire: Consultancy, Research Funding; Gilead: Consultancy, Research Funding; Abbvie: Consultancy, Research Funding. Foà:Pfizer: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Pfizer: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celltrion: Membership on an entity's Board of Directors or advisory committees; Abbvie: Consultancy, Speakers Bureau; Roche: Consultancy, Speakers Bureau; Celltrion: Membership on an entity's Board of Directors or advisory committees; Shire: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Roche: Consultancy, Speakers Bureau; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Incyte: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Incyte: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Abbvie: Consultancy, Speakers Bureau; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Amgen Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Amgen Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Shire: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Boccadoro:Sanofi: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; Amgen: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Bristol-Myers Squibb: Honoraria, Research Funding; AbbVie: Honoraria; Mundipharma: Research Funding. Coscia:Karyopharm Therapeutics: Research Funding; Gilead: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Abbvie: Membership on an entity's Board of Directors or advisory committees.

Introduction: Erythropoietin stimulating agents (ESAs) are first-line therapy for International Prognostic Scoring System (IPSS)-low risk myelodysplastic syndrome (MDS) when symptomatic anaemia (Hb Attempts have been made to build prognostic scores (integrating transfusion need, erythropoietin level, R-IPSS and ferritin) able to predict response to ESAs (6-7). No data concerning the predictive value of morphological and immunohistochemical analysis on bone marrow biopsy in low risk MDS patients are emerged till now. Methods: We retrospectively examined 96 IPSS low/int-1 MDS patients treated with ESAs in order to evaluate the morphological and immunohistochemical features of the bone marrow biopsies performed at baseline. All the patients had hemoglobin (Hb) ≤10 g/dL and serum EPO A detailed analysis of the morphological features (including quantitative and qualitative changes in the erythroid, myeloid and megakariopoyetic lineages) was performed, together with an immunohistochemical evaluation of p53 expression and CD34-positive blasts percentage. Results: Sixty-eight percent of the patients were classified as responder while 32% as non-responder. The morphologic profiles of the responder and non-responder did not differ significantly. A significant correlation was found between the response to the therapy and a percentage of CD34-positive blasts > 3% (univariate analysis: p= .0211). Moreover p53 expression in less than 1% of the nucleated cells correlated with the treatment response (univariate analysis: p = .0086). These results were also confirmed on multivariate analysis (p= .002). Fifty-eight percent of patients maintained response to ESAs for the entire duration of the follow up while 42% lost the response (median follow up: 35 months). More than 3% CD34-positive blasts was associated with a higher probability to lose the response to ESAs (p = .00003). Kaplan-Meier method was than applied to estimate the response duration. Patients with more than 3% CD34-positive blasts showed earlier loss of response in comparison with those with a lower percentage of blasts (p value= .0003; HR=3.9, IC 95% 1.8154-8.6238). Finally, the expression of p53 in more than ≥ 1% of the nucleated cells correlated with the loss of response before 24 mounts (p value= 0.029). Conclusions: Our study identifies 2 well-known parameters that could be useful to better predict outcome of ESAs therapy in low risk MDS patients. Therefore role of bone marrow biopsy together with its diagnostic contribution in the clinical evaluation of MDS patients (cellularity, morphologic dysplasia, percentage of CD34-positive blasts, grading of bone marrow fibrosis) could be helpful as a predictive tool in ESAs candidate patients. Further studies based on larger series of patients are needed to confirm these preliminary results. Disclosures Reda: Gilead: Consultancy; ABBVIE: Consultancy; Janssen and Cilag: Consultancy; Celgene: Consultancy. Riva:Jannsen and Cilag: Consultancy; Novartis: Consultancy; Celgene: Consultancy. Molteni:Janssen and Cilag: Consultancy; Novartis: Consultancy; Italfarmaco: Consultancy; Celgene: Consultancy; AMGEN: Consultancy. Cortelezzi:abbvie: Consultancy; novartis: Consultancy; roche: Consultancy; janssen: Consultancy.

BACKGROUD. The B-cell receptor inhibitor ibrutinib has significantly improved treatment and overall management of chronic lymphocytic leukemia (CLL). Although several data derived from clinical trials suggest that ibrutinib increases the risk of atrial fibrillation (AF), the incidence of AF in a real-life cohort of CLL patients is unknown. Furthermore, it would be clinically relevant to identify patients at high risk of AF during ibrutinib. The aim of this study is to report the prevalence and risk factors of AF in ibrutinib-naive CLL, in order to define a predictive model for the development of AF and to test it in a cohort of subjects receiving ibrutinib. METHODS. We retrospectively analyzed data from 860 ibrutinib-naive CLL patients, referred to the Padua University hospital. Comorbidities, clinical and biological prognostic markers were analyzed using the Mann-Whiney, Fisher exact or Chi-square tests, when appropriated. Time to AF (TTAF) and overall survival (OS) were evaluated with Kaplan-Meier method. Univariate and multivariate Cox models were run to identify independent factors associated with AF. Then, risk values were obtained based on the hazard ratios. The score for AF was calculated as the sum of each risk values. Subsequently, the model was evaluated in a cohort of 354 ibrutinib-treated patients referred from 8 Italian hematological centers. RESULTS. Among the 860 patients from Padua hospital, 60% were male, 49% were older than 65 years, 73% were Binet A stage at diagnosis and 41% underwent at least one line of treatment. A prior history of AF was present in 21 patients (2.4%) at CLL diagnosis, while, among the remaining 839 patients without a previous history of AF, 47 (5.6%) developed it after a median follow-up of 9.4 years, resulting in an estimated incidence of almost 0.8% cases/year. Moreover, the median OS for patients with AF was significantly shorter than that patients without AF (12 vs 22 years, p65 years (p=0.001, 1 point), male gender (p=0.003, 1 point), valvular hearth diseases (p=0.001, 2 points), cardiopathy (p Subsequently, we applied our AF model to a cohort of 354 ibrutinib-treated patients, 64% were male, the median age was 69 years, 88 were treatment-naive, 70% U-IGHV and 39% harbored TP53 abnormalities. Forty-four subjects developed AF after a median observation of 25 months, with an estimated 2-year TTAF of 12%. Only 9 out of the 44 patients (20%) discontinued ibrutinib. Sixteen patients (4%) were classified as AF score 0, 218 (62%) score 1-2, 73 (21%) score 3-4 and 46 (13%) at least score 5. Our model was also able to identify patients at a higher risk AF during ibrutinib, in fact the 2-year risk of AF was 0%, 5%, 17% and 40% for patients with score 0, 1-2, 3-4, and ≥5 respectively (p CONCLUSIONS. In this study, variables associated with an increased risk of developing AF were identified and recapitulated into a scoring system. Our model proved to be a valid tool to identify patients at a higher risk of developing AF, including ibrutinib-treated patients. Taking these data into account, patients with a score ≥5 should be carefully monitored during ibrutinib treatment given the very high-risk of developing AF or should be considered for alternative therapies. Disclosures Visentin: janssen: Consultancy, Honoraria. Mauro:abbvie: Other: board member; janssen: Other: board member. Reda:Janssen and Cilag: Consultancy; ABBVIE: Consultancy; Gilead: Consultancy; Celgene: Consultancy. Molica:Jansen: Other: Advisory board; Gilead: Other: Advisory board; Roche: Other: Advisory board; AbbVie: Other: Advisory board. Rigolin:Gilead: Research Funding. Tedeschi:Gilead: Consultancy; Janssen: Consultancy, Speakers Bureau; AbbVie: Consultancy. Cortelezzi:novartis: Consultancy; abbvie: Consultancy; roche: Consultancy; janssen: Consultancy. Coscia:Abbvie, Gilead, Shire: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen, Karyopharm: Research Funding. Cuneo:Abbvie: Other: advisory board, Speakers Bureau; Roche: Other: advisory board, Speakers Bureau; Gilead: Other: advisory board, Speakers Bureau; janssen: Other: advisory board, Speakers Bureau. Foà:CELGENE: Other: ADVISORY BOARD, Speakers Bureau; CELTRION: Other: ADVISORY BOARD; ABBVIE: Other: ADVISORY BOARD, Speakers Bureau; JANSSEN: Other: ADVISORY BOARD, Speakers Bureau; GILEAD: Speakers Bureau; NOVARTIS: Speakers Bureau; AMGEN: Other: ADVISORY BOARD; INCYTE: Other: ADVISORY BOARD; ROCHE: Other: ADVISORY BOARD, Speakers Bureau. Trentin:Roche: Membership on an entity's Board of Directors or advisory committees; Abbvie: Honoraria; Gilead: Research Funding; Janssen: Research Funding.

Introduction. Chronic Lymphocytic Leukemia (CLL) is an indolent B-cell lymphoproliferative disorder. Several prognostic factors such as IGHV mutation status and chromosomal aberrations as trisomy 12, del11q, del13q or del17p have been detected so far. More recent genetic mutations such as BIRC3, SF3B1, NOTCH1 and TP53 stratifies the prognosis and outcome in CLL patients (pts). However all data above reported, because of expensive techniques and experience typical of big laboratories, are not available to all medical centers. Data concerning the prevalence of hypogammaglobulinemia, IgM or IgG monoclonal gammopathy, and the impact on natural history of CLL pts are controversial and contradictory. The aim of the study is to evaluate the prevalence and the outcome of monoclonal IgM/CLL, IgG/CLL and hypogammaglobulinemia compared with CLL pts with normal immunoglobulin (Ig) levels. Patients and methods. We collected from three different Italian centers 902 pts diagnosed with typical CLL from 1987 to 2017 with a baseline assessment of serum Ig, immunofixation, chromosomal aberrations and clinical features; evaluating their impact on time to progression (TTP), time to treatment (TTT). Results. Once assessment was made, pts included in our study who met eligibility criteria were 902. Fifty-one patients showed IgM monoclonal gammopaty (5,6%); 89 showed IgG (9,9%), 103 patients had hypogammaglobulinemia (11,4%), 659 patients (73%) showed normal gamma level. In the Padova group, the overall prevalence of monoclonal gammopathy is 15.5% of whom 35 pts (10.5%) with IgG/CLL, 17 pts (5%) with IgM/CLL, 45 pts (13.5%) with hypogamma/CLL and 238 pts (71%) with no evidence of paraprotein. Data from the Rome group showed similar results: monoclonal gammopathy is 15.4% of whom 37 pts (9%) with IgG/CLL, 26 pts (6.4%) with IgM/CLL, 42 pts (10.3%) with hypogamma/CLL and 304 pts (74.3%) with no monoclonal gammopathy revealed. In the group from Milano, the prevalence of monoclonal gammopathy is 15.7%; 17 pts (10.7%) with IgG/CLL, 8 pts (5%) with IgM/CLL, 16 pts (10%) with hypogamma/CLL and 118 pts (74.3%) with negativity at immunofixation. Median age was similar in all the groups (66years, range 26-89years) and data gathered from the 3 centers showed an overlapping rate in prevalence of monoclonal gammopathy in CLL and their related subclasses. Median TTP was 75 months (91 months for patients with normal gamma levels and 54 months for patients with abnormal gamma globulin, P Median TTT was 79 months (93 months for patients with normal gamma levels and 54 months for patients with abnormal gamma globulin, P Summary. Our study provided data about incidence and prognosis of monoclonal gammopaty and hypogammaglobulinemia in CLL patients. Twenty-seven percent of patients with CLL showed abnormal gammopaty; these alteration have a negative impact on TTP and TTT in these setting of patients. Finally our data also detected a particular subset of patients with IgM/CLL characterized by a worst TTP and TTT. Disclosures Visentin: janssen: Consultancy, Honoraria. Reda:ABBVIE: Consultancy; Gilead: Consultancy; Janssen and Cilag: Consultancy; Celgene: Consultancy. Trentin:Roche: Membership on an entity's Board of Directors or advisory committees; Abbvie: Honoraria; Gilead: Research Funding; Janssen: Research Funding.

Background: Severe thrombocytopenia is an uncommon event in patients (pts) with lower-risk MDS, but it may significantly affect the prognosis. No specific pharmacological approaches other than hypometilating agents (not licensed in Europe in lower-risk MDS), able to improve platelet count in this setting, are currently available. Trials testing efficacy and safety of Eltrombopag are ongoing (Oliva 2017). Few data were reported about danazol, an attenuated androgen, that seems to have also some effectiveness in this still unmet need (Wattel 1994; Chan 2002). Aims: To assess the efficacy and safety of danazol in improving the platelet count in low risk MDS pts with severe thrombocytopenia. Methods: We retrospectively reviewed 35 thrombocytopenic MDS pts treated with danazol. The initial and maximal dose was 600 mg/day for all pts, modulated according to response and toxicity. The response was evaluated according to IWG response criteria (Cheson 2006). The outcome was strictly observed every 3 months (mo) up to the 12th mo, and the platelets average number in each observation moment was described. The time to response, the response rate and the enduring of response were also recorded. Results: Of the 35 pts, according to 2016 WHO classification, 4 pts were MDS-ULD; 19 were MDS-MLD (3 of them with medullar hypocellularity), 7 were MDS-EB1 and 5 were affected by MDS/MPN. At baseline the platelet count was lower than 20x10^3/mL in 11 pts, the median was 23x10^3/mL . At starting time of danazol therapy the IPSS-R cytogenetic class of risk was very low in 2 cases, low in 28 cases, intermediate in 3 cases and very high in 1 case. Cytogenetic was not available in one patient. In the 30 MDS pts, the IPSS-R was "very low" in 1 patient, "low" in 16, "intermediate" in 7, "high" in 4 and "very high" in 1. In 1 case it was not evaluable due to the lack of cytogenetics. Two pts were not included in the analysis because they were treated for less than 3 mo (in 1 case danazol was withdraw to permit the beginning of another therapy and in 1 case due to death for other neoplastic disease). The response rate was 63,6% (21 responders on 33 evaluable). Median time to response was 3.5 mo (range 0.3 - 12.4 mo); the average response time was 5.09 mo. In the first year of treatment, the platelet count (evaluated at baseline, 3, 6, 9 and 12 mo) changed in a significant way (F test after repeated measures ANOVA: p < 0.001 as shown in Figure 1). Pairwise comparisons of platelet count according to Bonferroni showed a significant difference for baseline vs. 3 mo (p = 0.0013), baseline vs 6 mo (p = 0.0255), baseline vs 9 mo (p = 0.0047) and baseline vs 12 mo (p = 0.0014); however, no significant differences (p ≥ 0.05) in counts were seen for all the further pairwise comparisons at 3, 6, 9 and 12 mo. The median and average duration of the response for the entire population were respectively 12,5 and 32,5 mo. Only 6 of the 21 responders (28%) lost the response (the median and average duration of response were respectively 5.8 and 12.9 mo). Within the 21 responders, the median progression free survival was not reached after 24 mo. The probability to maintain the response after 50 mo was assessed at 58.2% (C.I. 24.1% to 81.4% - Figure 2). The overall survival showed a significant difference (logrank test: p = 0.0064) between responders and non-responders (Figure 3). Adverse events recorded were as follows: moderate (grade 1 and 2) increase in transaminases in 4 cases (with reduction of danazol to 400 mg/day); 1 case of severe but reversible liver toxicity (grade 3) (with subsequently drug suspension); severe (grade 3) but reversible renal failure in 1 case (the drug was stopped); moderate (grade 1 and 2) increasing of serum creatinine in 6 case (with reduction of danazol to 400 mg/day in 2 of these); reversible cutaneous rash in 3 cases; amenorrhea in 1 case (the only fertile woman in the series); weight loss and loss of appetite in 1 case, weight gain in 1 case. Conclusion: Even if the mechanism of action of danazol in pts with MDS is unclear, this series confirms its efficacy to improve platelet count in the most of MDS pts with severe thrombocytopenia. The response was often clinically significant. It may not be immediate but seems to be reachable after 3-6 mo of treatment. A responsive patient has a good probability to maintain a long-lasting response. The toxicity profile of this drug is acceptable. Waiting for more effective options, danazol may be a good therapeutic option for these pts. Disclosures Riva: Jannsen and Cilag: Consultancy; Novartis: Consultancy; Celgene: Consultancy. Reda:Celgene: Consultancy; Janssen and Cilag: Consultancy; Gilead: Consultancy; ABBVIE: Consultancy. Molteni:AMGEN: Consultancy; Novartis: Consultancy; Italfarmaco: Consultancy; Celgene: Consultancy; Janssen and Cilag: Consultancy.

Introduction. Patients with CLL and FISH positive for trisomy 12 (+12) have unique clinical and biological features. We, therefore, performed an analysis of the association between demographic, clinical, laboratoristic and biological features and outcomes in treatment-naive patients with +12 CLL. Methods. This study included 312 treatment-naive patients with +12 CLL from 9 centers. These patients, diagnosed between January 2000 and July 2016, were compared to a control group of 580 treatment-naive patients with FISH negative CLL, matched by age and gender and followed in the same centers. An additional cohort of 250 patients with +12 CLL followed at a single US institution was used as external validation. Results. Patients' baseline characteristics are shown in Table 1. As compared to patients with negative FISH, patients with +12 had a significant higher prevalence of elevated LDH (p Conclusions. In this large cohort analysis of 321 patients with +12 CLL, we were able to confirm that LDH levels above normal are common in this group and we observed that LDH levels independently predict a shorter PFS, TFS and CLL-specific survival in this population. LDH levels at diagnosis could allow to suspect trisomy 12 in CLL patients and predict different prognosis. Disclosures Coscia: Karyopharm: Research Funding; ROCHE: Honoraria, Other: Advisory board; Gilead: Honoraria; Mundipharma: Honoraria; Janssen: Honoraria. D'Arena:Janssen-Cilag: Honoraria. Reda:Gilead: Research Funding; Roche: Membership on an entity's Board of Directors or advisory committees.

Introduction: chronic lymphocytic leukemia (CLL) is an indolent disease, but 17p deleted (del) and/or patients who experience early relapse or not responding to chemoimmunotherapy have a very poor outcome. In these patients an allogeneic stem cell transplantation (alloSCT) is indicated, whenever possible. B-cell receptor inhibitors (BCRi) have shown high efficacy with a low toxicity, making the choice of an alloSCT challenging even in high risk patients. The aim of the study is to highlight the outcome of different clinical approaches available in the era of the new drugs. Method: this is a multicenter retrospective analysis on 88 high risk patients treated in 8 Italian Centers. Inclusion criteria were: i) age ≤ 70 years; ii) responding to one of the EBMT (European Bone Marrow Transplantation) criteria for elegibility to alloSCT: relapse within one year after purine-analogues or two years after chemioimmunoterapy or autologous-SCT (ASCT); de novo or acquired 17p del; iii) alloSCT from 2001. Patients who received BCRi before alloSCT or ineligible to alloSCT due to comorbidities were excluded. Patients were assigned to alloSCT or BCRi based on physician and/or patient choice or unavailability of a donor. The analysis started from the transplant date or the start date of BCRi therapy. Results: 50 patients (M/F: 42/8) received an alloSCT, and 38 (M/F 30/8) were treated with BCRi (ibrutinib n=28, rituximab-idelalisib n=10). Median age was 55 (range, 34-68) in alloSCT and 60 years (42-69) in BCRi (p=0.06). Time from diagnosis to alloSCT or BCRi was 59,4 (range, 5-210) and 86,3 months (1-211) (p=0.15), respectively. Fluorescence in situ hybridization (FISH) data were available in 34/50 (68%) alloSCT patients: 17p del was positive in 21 (62%) (de novo n=12, acquired n=8, unknown n=1). Elegibility criteria for alloSCT group were: early relapse n=11, refractory n= 7, ASCT relapse n=11, 17p del n=21 (of which 11 were also chemorefractory). FISH data were available in all BCRi patients: 17p del was positive in 26 (68%) (de novo n=8, acquired n=14, unknown n=4). Elegibility criteria for BCRi group were: early relapse n=2, refractory n= 9, ASCT relapse n=1, 17p del n=26 (of which 16 were also chemorefractory). AlloSCT group had more patients in early relapse or with a failed ASCT (p=0.03 and p=0.01). Heavy chain gene rearrangement was available in 26/50 (52%) alloSCT and 35/38 (92%) BCRi patients and was unmutated in 87% and 86%, respectively. The median number of previous therapy was 2 in both groups (alloSCT: range 1-7; BCRi: range 0-8, p=0.25). Reduced-intensity conditioning regimen was used in 48/50 alloSCT patients, and donor type was sibling in 19, matched unrelated in 26 and haploidentical in 5 cases. Disease status before alloSCT was complete remission (CR)=20, partial remission (PR)=17, stable/progressive disease (SD/PD)=13. The median follow-up was 33 months (1-134) and 14 months (3-32), respectively for alloSCT and BCRi group (p=0.0008). Two-year OS was 59% vs 79% in alloSCT and BCRi, respectively (p=0.32). The cumulative incidence of relapse at 2 years was 30% in alloSCT and 23% in BCRi, with a non-relapse mortality of 20% after alloSCT. Median PFS was 18,6 months (range 1-134) and 12,6 (range 3-24,6) in alloSCT and BCRi, respectively. Two-year PFS was 54% in alloSCT and 77% in BCRi (p=0.19). The main cause of treatment failure was disease progression. In the BCRi group, 8 patients achieved CR at the last follow-up, 5 patients relapsed and died of progressive disease (2 with Richter's transformation), 1 patient died of second cancer. In the alloSCT group, 17 patients were alive and in CR, 11 CR patients died of transplant-related-mortality (6 graft-versus-host disease, 2 infections, 1 embolism, 2 second cancers), 19 patients died in SD/PD at the last follow-up. Conclusions: these retrospective data showed that so far no significant difference in the outcome of 17p del and/or refractory CLL patients have been observed after either alloSCT or BCR inhibitors. The significant different follow-up of the two groups implies some limits: i) BCR inhibitors still have to show long term responses; ii) alloSCT results may improve over the next future by a better selection of eligible patients and the improvement of the transplant procedures. Hopefully, the combination of the two strategies will increase the chance of cure of poor risk CLL patients. Disclosures Reda: Roche: Membership on an entity's Board of Directors or advisory committees; Gilead: Research Funding.

INTRODUCTION Platelet function has never been studied systematically in patients with CLL. Novel drugs are now available for CLL treatment that may impact on platelet functions. Fifty per cent of patients treated with Ibrutinib suffered from minor bleedings and only 5% from major bleedings, partly caused by the drug driven inhibition of platelet glycoprotein VI signaling. No data on bleeding tendency has yet emerged on patient treated with Idelalisib, the first specific inhibitor of PI3K δ p110 approved for the treatment of relapsed/refractory CLL or for patients with del17p or TP53 as first line therapy. In animal models a reduction of p110δ on platelets (PLT) does not increase bleeding, causing only a slight reduction of platelet aggregation and activation. Knowledge about potential bleeding complications associated with the use of small molecules may be relevant in older patients and those at increased bleeding risk due to concomitant therapies. PATIENTS AND METHODS Ten patients with CLL (M/F: 6/4; median age: 71 years, range 47-82) who started therapy with Idelalisib were enrolled in a prospective observational pilot study. The Bleeding Severity Score (BSS), a validated questionnaire, was administrated to patients to estimate bleeding before and during idelalisib therapy. All patients underwent coagulation tests and platelet aggregation/secretion studies with different aggregating agents before starting therapy with Idelalisib, after 28 + 7 days and after 3 months. Patients with a platelet count less than 80.000/mm3, in antiplatelet or anticoagulant therapy, with recent use (within 7 days) of NSAIDs and a diagnosis of hereditary thrombocytopenia/pathy were excluded. We defined complete haematological remission (CHR) as Hb more than 11g/dl, PLT more than 100.000/mm3, lymphocyte less than 5.000/mm3 and partial haematological remission (PHR) as a response not fulfilling criteria for CHR. RESULTS No cases of hemorrhagic complications or increased bleeding tendency were observed in patients with CLL and no patients had a pathologic BSS (>5) at enrolment. All patients had coagulation tests within normal limits at baseline and after 28 days. Platelet count was below 100.000/mm3 in 5 patients. In 9 out of 10 patients platelet aggregation was pathological with at least 2 of the 4 aggregating agents tested. Platelet secretion before initiation of treatment with Idelalisib was particularly impaired with ADP (8/10 patients), while was pathological with collagen, a strong agonist, in only 2 patients. In 8 patients intraplatelet ATP/ADP ratio was pathological, as observed in delta storage pool disease. After 28 days of treatment 4 of 10 patients were in CHR and 3 in PHR. Platelets count was still below 100.000/mm3 in 2 subjects. At 28 days in 5 out of the 9 patients with pathological baseline test, platelet aggregation improved, while 3 remained unchanged and in one worsened. Even ADP secretion normalized in 4 patients. ATP/ADP ratio did not significantly change. At three months 7 patients reached CR and 2 reached PR. At three months platelets count was still below 100000/mm3 in 2 patients. In 3 patients platelet aggregation further ameliorated. CONCLUSIONS In this pilot study, treatment with idelalisib improved platelet aggregation tests in most of the CLL patients who presented a pathological test before starting therapy. It's unlikely that the drug has a direct effect on platelets, given their low expression of PI3Kδ; therefore our results are probably due to the rapid idealisib effect on CLL clone. Based on these preliminary data, Idelalisib seems to be safe in patients with an increased bleeding risk. Disclosures Reda: Roche: Membership on an entity's Board of Directors or advisory committees; Gilead: Research Funding. Peyvandi:Alexion: Other: research funding paid to Luigi Villa Foundation, Research Funding; Ablynx: Membership on an entity's Board of Directors or advisory committees, Other: research funding paid to Luigi Villa Foundation, Research Funding; CSL Behring: Speakers Bureau; Biotest: Other: research funding paid to Luigi Villa Foundation, Research Funding, Speakers Bureau; Octapharma: Consultancy; Kedrion Biopharma: Consultancy, Other: research funding paid to Luigi Villa Foundation, Research Funding; LFB: Consultancy; Grifols: Speakers Bureau; Novo Nordisk: Other: research funding paid to Luigi Villa Foundation, Research Funding, Speakers Bureau; SOBI: Speakers Bureau; Bayer: Speakers Bureau.

Azacitidine (AZA) is effective in high risk myelodysplastic syndromes (MDS), chronic myelomonocytic leukemia type 2 (CMML-2) and low blast count acute myeloid leukemia (AML) patients not suitable for more intensive treatment. Factors that may influence response to AZA are still under investigation. Bone marrow fibrosis is a potentially negative prognostic marker on overall survival (OS), but its clinical significance in this setting of patients remains to be clarified. We evaluated clinical predictors of OS and overall response rate (ORR; complete/partial response CR/PR; stable/progressive disease SD/PD) to AZA in a real life cohort. We studied 94 consecutive patients, treated at two Institutions from June 2009 till February 2016 with AZA subcutaneously (5+2+2 schedule) every 28 days, outside clinical trials. We analyzed data from routine laboratory analysis, bone marrow histology, morphology and cytogenetics at diagnosis. OS was measured from the starting of AZA treatment. Table 1 shows the clinical characteristics pre- and post-AZA: most patients (68%) were AREB1 or AREB2, 13% RCUD/RCMD or MDS NOS according to WHO 2008 classification, 17% AML, 2% CMML. At the onset of AZA therapy the majority of MDS cases (68%) showed an intermediate-2 risk, according to the International Prognostic Scoring System (IPSS) and high/very high risk (78%) according to IPSS-revised. Secondary and de novo cases, as well as cytogenetics risk groups, were equally represented; 50% of patients were transfusion dependant and moderate to severe neutropenia or thrombocytopenia were present in roughly 50/70% of cases respectively. As expected, bone marrow biopsies pre-AZA showed hypercellularity in most patients (65%). Remarkably, 47,5% of cases showed bone marrow fibrosis of ≥1 grade before AZA initiation. These findings were mostly unchanged at post-AZA evaluation. On the whole, 93 patients receiving > 4 cycles of therapy were available for response evaluation according to International Working Group 2006 criteria. After a median of 6 cycles (4-44), ORR was 41.9% (CR 18.3%, PR 11.8%, SD with hematologic improvement HI 11.8%), SD was 21.5%, PD 10.7% and 25.8% failed to achieve a response. Thirteen percent of patients reached at least partial cytogenetic response and 50% a HI. ORR was not influenced by monocytosis, neutropenia or IPSS cytogenetic risk category. Interestingly, pre-AZA marrow blast percentage, cytogenetic risk, time from diagnosis to AZA and the interval from 1st to 6th cycle had no impact on response. As regards marrow characteristics, patients with MF-0 pre-AZA displayed significantly lower PD rate and higher ORR, SD and HI than those with any grade of fibrosis (21.4% vs 51.4% and 78.6% vs 48,6%, respectively p=0.006, Fig1). This observation was also confirmed at marrow evaluation after AZA (22% versus 48% for PD and 78% versus 52% for ORR/SD/HI, p=0.05, Fig1). Regarding cellularity pre- and post-AZA, higher ORR,SD and HI and lower PD were observed for patients with normo/hypo compared to those with hyper-cellularity (Fig1) although not significantly. Forty-one percent of cases presented a hematologic toxicity (33% neutropenia and 18% thrombocytopenia of any grade) occurring after a median of 2 (1-18) AZA cycles. Moreover 28.6% of patients had an infection during AZA treatment, not related to neutropenia degree. Of note, toxicities did not affect median time from the 1st to the 6th AZA cycle (170,115-240 days), nor ORR. Median OS from the beginning of therapy was 18.5 months (12.7-24.4, 95% CI). IPSS high category [HR 2.24 (1.19-4.20) p=0.01], poor cytogenetics [2.19 (1.27-3.78) p=0.005], and lower ORR [0.46 (0.26-0.80) p=0.006] significantly affected OS. Unexpectedly, a response obtained after less than 4 cycles negatively impact OS [HR 0.86 (0.80-0.92) p Disclosures Reda: Roche: Membership on an entity's Board of Directors or advisory committees; Gilead: Research Funding.

Background: chronic lymphocytic leukemia (CLL) is characterized by progressive immunodeficiency with high prevalence of infections, autoimmune phenomena and secondary malignancies. The immune deregulation may be due to the disease itself or it may be a consequence of the treatment performed. Despite the use of highly effective chemo-immunotherapy, CLL remains incurable nowadays, even if the availability of new drugs is improving life expectancy. Aims: to evaluate the incidence of second cancers in CLL patients, and to investigate their relationship with disease features and therapy lines. Methods: 514 CLL patients diagnosed and followed from 1983 until 2014 at our Institution were retrospectively evaluated. Secondary cancers were categorized according to the originating organ or tissue; skin cancers were divided into melanoma and non-melanoma. History of neoplasia preceding CLL diagnosis was also registered. Results: clinical, hematological and biological characteristics at CLL diagnosis are listed in Table 1. During the follow up 88 patients (17%) developed secondary cancers, with a mean time from diagnosis to secondary neoplasia of 9 years. Considering tumor site, we observed 9 hematological malignancies, 9 lung, 5 breast, 19 uro-genital tract (5 kidney, 10 prostate, 4 bladder, 2 uterus, and 2 ovarian), 15 gastro-enteric tract (12 colon, 2 gastric and 1 tongue), 4 pancreas, 3 melanoma and 15 skin cancers other than melanoma. No significant differences were observed according to age, gender, Rai/Binet stage and hematologic parameters in patients with or without secondary tumors (Table 1). Considering prognostic features, no association was found with 13q deletion, chromosome 12 trisomy, VHIG mutational status, or with ZAP-70 and CD-38 positivity. On the contrary, the development of second cancers was associated with the presence of chromosome 17p (8% with secondary neoplasia versus 6% without, p=0.05) and 11q deletions (13% versus 9%, p=0.08). Medical history was positive for malignancies in 70 patients (13%): 2 hematological malignancies, 3 airways (2 lower and 1 upper), 3 breast, 6 uro-genital tract (3 bladder, 3 prostate, 2 uterus and 1 ovarian), 3 gastro-enteric tract, 3 skin cancers other than melanoma, and 3 melanoma. As regards treatment, 46/88 (52.3%) and 219/426 (51.4%) patients with or without secondary cancers, underwent at least one therapy line. Eighty-six patients were treated with fludarabine containing regimens, of whom 11 developed a secondary cancer; 180 patients received chlorambucil and 34 developed a secondary tumor. Among 65 patients who underwent alemtuzumab treatment, 10 were later diagnosed with a second cancer. During the follow up, 121 patients died, 18 with secondary malignancy. Of note, 41 patients died from CLL progression, 2 from thrombotic events, 11 from infections and 8 from secondary malignancy. Conclusions: secondary malignancies are not infrequent in patients with CLL and their occurrence is not clearly related to biologic markers or to the treatment performed. A careful clinical follow up, encompassing sex and age adjusted tumors screening, is advisable for an early diagnosis and appropriate treatment of secondary malignancies in CLL. Table 1. clinical and laboratory features of 514 CLL patients with or without secondary malignancies. Data are expressed as median (range) or absolute number (%). Secondary malignancies Yes (N=88) No (N=426) Age years 64 (39-80) 63 (31-90) Gender M/F 57/31 250/176 Follow-up years 12 (0-30) 12 (1-25) Rai/Binet C/III 85 (97) 3 (3) 401 (94) 25 (6) WBC x10e3/mmc 18.74 (3.6-138) 17.3 (3-384) ALC x10e3/mmc 12.63 (1.8-91.8) 11.9 (1.4-381) Hb g/dL 14 (9-17) 14 (8-18) PLT x10e3/mmc 198 (77-608) 184 (58-472) LDH U/L 325 (144-838) 334 (142-795) Beta2microglobulin mg/L 2 (1-23) 2 (0-10) FISH*Del11qDel13qDel17p+12 6 (13) 19 (40) 4 (8) 6 (13) 23 (9) 101 (40) 15 (6) 38 (15) VHIG unmutated** 15 (42) 80 (39) ZAP-70 positive*** 14 (39) 73 (36) CD-38 positive**** 15 (42) 76 (37) *Tested in 48 and 252 patients respectively. **Tested in 36 and 205 patients respectively. ***Tested in 33 and 182 patients respectively. ****Tested in 56 and 291 patients respectively. Disclosures No relevant conflicts of interest to declare.

BACKGROUND Richter syndrome (RS) is associated with unmutated VHIG status, VHIG 4 -39 sequences, stereotyped B-cell receptors and expression of ZAP70, CD38 and CD49d, as well as with a frequent disruption of TP53, ATM and CDKN2A, and mutational activation of NOTCH1. RS presents with extranodal involvement including gastrointestinal tract, lung, kidney, eye, testis, central nervous system, and skin. Extranodal RS presenting as skin lesion is extremely rare with only few cases reported and a biological and molecular characterization of these cases is still lacking. On the basis of these observations, we undertook a comprehensive characterization of a rare cutaneous RS transformation of CLL to DLBCL and investigated prognostic biological implications. CASE A 59 year-old woman affected by CLL, stage III/B, 13q14 and 11q23 deletion, presenting massive splenomegaly and pleural effusion underwent treatment with fludarabine-cyclophosphamide and rituximab (FCR). Third cycle was complicated by prolonged neutropenia, and chemotherapy was discontinuated. CT scan documented complete remission and bone marrow (BM) biopsy showed initial myelodysplastic features and presence of 7q deletion. Complete remission (CR) with incomplete recovery was achieved, and patient continued follow-up. As persistent neutropenia was observed, subsequent BM evaluation was performed showing unchanged morphology and normal cytogenetic. No signs of CLL relapse were present. Eight years later, the patient presented edema of the right foot, rapidly worsened until prevent independent walking. Numerous hard papules and plaques appeared and multiple nodules were appreciable in subcutaneous tissue of both thighs and legs. B symptoms were absent. CBC count showed persistent mild leucopenia and LDH levels were not increased, Ultrasound of foot soft tissues revealed an organized anechoic nodal mass. Hystological examination documented a diffuse proliferation of large lymphoid cells, with a centroblastic morphology infiltrating the subcutaneous soft tissues displaying the following immunophenotype: CD20+, CD3-, CD5+, CD23+/-, cyclinD1-, bcl2+, CD10- bcl6-, MUM1+/-, EBV-, ZAP70-, p53 -, Ki67 40-50%. 11q23 deletion was also observed by FISH on formalin-fixed, paraffin embedded section suggesting that cutaneous lymphoma and leukemia arose from the same clone. Furthermore, NOTCH1 hotspot mutation (c.7544_7545delCT) was absent both on foot soft tissues sample and on cryopreserved peripheral blood of CLL diagnosis. CT scan was normal except for mild splenomegaly, while Positron Emission Tomography (PET) showed intense uptake on right ankle, multiple nodular in subcutaneous tissue of lower limbs and feet. Cutaneous DLBCL consistent with RS was diagnosed and patient received 6 courses of R-CHOP. PET after 3 cycles of treatment show reduction of uptake and an evaluation at the end of therapy confirmed CR of RS that continued after 12 months of follow-up. CONCLUSION Cutaneous RS is exceptionally rare with only few reports or small case series described in literature In this study, we present a case of cutaneous RS occurred in patient in CR after chemo-immunotherapy for CLL. To the best of our knowledge, this is the first investigation assessing a comprehensive biological and molecular characterization of cutaneous RS case. Finally, we pointed out as the present case is interesting since it may represent a model of RS that diverges in prognosis from nodal involvement. Disclosures No relevant conflicts of interest to declare.

Abstract 4598 Immune thrombocytopenia (ITP) is a common autoimmune complication in chronic lymphocytic leukemia (CLL), occurring in up to 5% of patients. The occurrence of alemtuzumab-associated ITP have been rarely reported in CLL and it has never been reported so far as a significant event complicating alemtuzumab treatment in clinical trials. Recently, a new distinctive form of secondary ITP occurring in 6 out of 215 patients with relapsing-remitting multiple sclerosis treated with alemtuzumab in a randomized, controlled phase II trial has been reported (Cuker et al, Blood 2011). We investigated the incidence of ITP in a cohort of 64 consecutive patients treated with low-dose alemtuzumab for relapsed/refractory CLL from 2003 to 2010. Subcutaneous alemtuzumab was administered at the dose of 10 mg three times a week, up to 18 weeks. ITP was documented in 12/64 patients: in 3 patients (4.7%) ITP developed before alemtuzumab treatment and no relapses of the autoimmune disorder were observed during the treatment; in 9 patients (14.8%, with an incidence of 5.7 events/100 patient-year) ITP developed after alemtuzumab treatment. Median time to ITP from initial alemtuzumab exposure was 12 months (range 1–42 months). Concomitant hemolytic anemia (Evans syndrome) was observed in one patient. At ITP onset, median platelet counts were 11×109/L (range 3–70) and anti-platelet antibodies (Capture P® Method, ImmucorGamma, Norcross GA, USA) were found in 7 of the 8 patients tested. No patients showed severe or life-threatening bleeding. Three of nine patients who developed ITP after alemtuzumab therapy, experienced CLL progression requiring chemo-immunotherapy after 3, 4 and 13 months from ITP onset, respectively. One patient achieved a partial remission of CLL with ITP resolution, while the other two died of disease progression. In the remaining six cases, ITP was not associated with disease progression and was treated with corticosteroids and/or intravenous immunoglobulins. Five patients achieved normal platelet counts, while one patient did not respond. Low-dose alemtuzumab (theoretical cumulative dose 540 mg, equal to half of the classic cumulative dose and one-third of the individual dose) is an effective, safe and well tolerated treatment for CLL, as reported by several recent studies (Cortelezzi et al, Leukemia 2009; Brit J Haematol 2011). In our cohort of CLL patients treated with alemtuzumab, the incidence of ITP was 14.8% that is almost three times higher than previously reported in CLL. These data may indicate a role of T-lymphocyte dysregulation induced by alemtuzumab in the pathogenesis of ITP. Our data also suggested the importance of monitoring platelet counts during follow-up in patients treated with low-dose alemtuzumab for both haematological and non-haematological diseases. Disclosures: No relevant conflicts of interest to declare.

Abstract 4963 Overall survival (OS) is significantly improved by 5-azacitidine in intermediate-2 (int-2) and high risk myelodysplastic syndromes (MDS), chronic myelomonocytic leukemia (CMML) with 10–29% marrow blasts, and acute myeloid leukemia (AML) with 20–30% marrow blasts, compared with conventional treatments, and currently appears as the standard of care, at least in patients who are not candidates to allogeneic stem cell transplantation (alloSCT). We retrospectively evaluated the efficacy and tolerability of 5-azacitidine in 25 patients treated at our institution from 2009 to 2012, outside of clinical trial. Our series was composed by 17 cases of MDS with IPSS risk int-2 or high, 6 AML with marrow blasts between 20% and 30% and 2 CMML. Patients were treated with 5-azacitidine at a dosage of 75 mg/m2/d subcutaneously for 7 days every 28 days (schedule 5 day on, 2 day off and 2 day on). Median age of our cohort was 72 years (range 37–81 y), male to female ratio was 0. 6 and the median number of cycles received was 7 (range 1–26). According to the MDS-specific comorbidity index 9 pts (53%) were classified as low-risk, 7 pts (41%) as intermediate risk and 1 pt (6%) as high risk. Seventeen (68%) patients (13 MDS, 3 AML, 1 CMML) who had received at least 4 cycles of therapy were evaluable. Median age of these 17 patients was 71 years (range 37–81 y), male to female ratio was 0. 8 and median number of cycles administered was 8 (range 4–26). The overall response rate (ORR) was 59% (10/17 patients). According to International Working Group (IWG) 2006 criteria, five patients (29%) reached complete remission (CR) after a median of 5 cycles of therapy (range 4–6), two patients (12%) obtained hematologic improvement with bone marrow complete remission (marrow CR) after 6 and 11 cycles of therapy respectively, three patients (18%) showed hematologic improvement (HI) after 5 cycles (range 4–6), while stable disease (SD) and progressive disease (PD) were observed in 4 (23%) and in 3 patients (18%) respectively after 5 cycles (range 4–7). Median duration of response was 12 months (range 6–26 mo); median overall survival from the beginning of 5-azacitidine, for all patients treated, was 14. 4 months (range 7–33 mo). We did not observe any differences in response rate according to age, bone marrow fibrosis, cytogenetics and transfusion requirements. In the responder group (10 patients) we did not observe grade 3 or 4 non-hematologic toxicity after a median observation time of 10 months (range 5–33 mo). Among non-responding patients, four (57%) recurred to hospitalization due to infectious or hemorrhagic complications (median observation time 15 months, range 7–33). 5-azacitidine confirmed to be an active therapy for patients with int-2 and high risk MDS and AML with low marrow blast counts not candidate to high intensity treatment for age and or comorbidities, showing high response rate and good tolerability. The low rate of serious adverse events and need of hospitalization improved patient's quality of life and reduced the utilization of medical resources. Disclosures: No relevant conflicts of interest to declare.

Abstract 4597 Toll-like receptors (TLRs) are major agents of innate immunity and initiators of adaptive immune response by acting as costimulatory signals for B cells and inducing maturation, proliferation and antibody production after pathogen recognition. They are also involved in the self-antigen recognition and could play a role in autoimmune phenomena. It is well established that B-chronic lymphocytic leukemia (B-CLL) is characterized by an increased incidence of autoimmune phenomena and immunodeficiency, which can greatly influence the disease outcome leading to a variable clinical course. The aim of this study was to evaluate the gene expression of TLRs in 97 B-CLL patients (median age 74 yrs, range 41–89, 41 female and 57 male) and to relate it with the clinical course of the disease (median follow-up 107 months, range 36–336), in particular with infections and autoimmunity, and the expression of prognostic factors (mutational status of IgVH region, CD38 and ZAP70 expression, and cytogenetic alterations). The gene expression of TLR4 and TLR9 was evaluated in total RNA of B cell from B-CLL patients and controls (pool of 10 healthy donors) by real-time PCR performed with a model 7300 real-time PCR system (Applied Biosystems). The TLR4 and TLR9 relative quantification expression (RQ) was normalized according to GAPDH (internal control gene) and to control mRNAs. We found that TLR4 gene expression was decreased (RQ=16.1+/−1.56) and TLR9 increased (RQ=2725+/−165) in B-CLL patients vs controls (RQ=100). TLR4 gene expression was reduced in: a) stage Binet B-C/Rai II-III-IV (n=20) versus low risk cases (Binet A/Rai 0-I) (10.8+/−2.2 vs 17.4+/−1.9, p=0.048); b) patients treated with I line therapy (n=25) and II line therapy (n=14) vs untreated patients (n=58) (13.1+/−2 vs 19.2+/−2.3, p=0.05, and 8.3+/−2.1 vs 19.2+/−2.3, p=0.03, respectively); c) patients untreated but with ITT and treated with stable disease or progressive disease (n=28) vs untreated and treated with DFS>24 months at the time of the investigation (n=69) (12+/−2 vs 17.8+/−2, p=0.048); d) patients with grade 2–4 infections (n=52), according to Common Terminology Criteria for Adverse Events, vs patients with grade 0–1 infections (13.2+/−1.5 vs 19.51+/−2.9, p=0.04); e) patients with autoimmune phenomena (n=12) vs cases without (8.8+/−2.5 vs 17.12+/−1.7, p=0.04). As far as TLR9 is concerned, we found that it was significantly reduced in untreated and treated with II line therapy patients vs patients treated with I line therapy (2549+/−183 vs 3528+/−356, p=0.01, and 1893+/−277 vs 3528+/−356, p=0.01, respectively). Finally, we found that patients with an unmutated IgVH region status (n=15) showed TLR4 gene expression significantly reduced compared with patients with mutated IgVH region status (n=29) (9.57+/−2.1 vs 18.8+/−3.2, p=0.028). (Data are expressed as mean+/−SE for all data). These results show that in B-CLL patients the reduced expression of TLR4 is consistent with a reduced ability to mount a proper immune response and it is even more pronounced in “active” patients that show high prevalence of infectious episodes and autoimmune phenomena. Disclosures: No relevant conflicts of interest to declare.

Abstract 2847 Chronic lymphocytic leukemia (CLL) is frequently complicated by autoimmune disorders, primarily autoimmune hemolytic anemia and immune thrombocytopenia (ITP). In order to investigate biological features related to ITP development, we retrospectively analyzed 463 CLL patients characterized for immunoglobulin heavy-chain variable (IGHV) gene mutational status, cytogenetic features and B-cell receptor (BCR) configuration (HCDR3) at the time of diagnosis. Thirty-six patients (7.7%) had developed ITP, according to our previously reported criteria (Visco et al, Blood 2008): i) an otherwise unexplained rapid (< 2 weeks) and severe fall (at least half of the initial level and below 100*109/L) of the platelet count; ii) normal or augmented number of megakaryocytes in the bone marrow; iii) no or limited (not palpable) splenomegaly and iv) no cytotoxic treatment in the last month. Stereotyped BCR configuration was defined by means of pair-wise alignment with known stereotyped sequences available from different public databases (Stamatopoulos et al, Blood 2007; Bomben et al, Br J Hematol 2009; Murray et al, Blood 2008), specifically excluding pairs of sequences whose length differed more than 3 amino acids and sharing more than 60% identity on alignments showing less than 3 gaps, as described by others and by our group (Stamatopoulos et al, Blood 2007; Maura et al, Plos One, in press). Our results indicated that the occurrence of ITP was strongly associated with unmutated (UM) IGHV (p Disclosures: No relevant conflicts of interest to declare.

Abstract 4030 INTRODUCTION: An increased bone marrow angiogenesis might be involved in the pathophysiology of a number of haematological malignancies, including myelodysplasia (MDS). Many angiogenic factors have been investigated in MDS, and vascular endothelial growth factor (VEGF) and its significance has been evaluated the most. VEGF mediates its biological effects by binding to two transmembrane tyrosine kinase receptors, VEGFR-1 and VEGFR-2. The VEGF/receptor signaling system is involved in the regulation of two fundamental processes: the formation of blood vessels (angiogenesis) and of blood cells (hematopoiesis). VEGF regulates the two processes by different mechanisms: hematopoietic stem cell survival and repopulation mainly via an autocrin loop, and angiogenesis via a paracrine loop. PATIENTS: The study population included 79 patients (pts) (48 men and 31 women; median age, 70 years). The patients were given a diagnosis of 10 RA, 6 RARS, 17 RCMD, 7 5q-syndrome, 25 RAEB-1 e 14 RAEB-2 according to the WHO classification (2008). In agreement with the International Prognostic Scoring System (IPSS), 28 pts were graded as Low, 28 as Int-1, 17 as Int-2 and 6 as High. According to the WHO classification based prognostic scoring system (WPSS), 14 pts were graded as Very Low, 17 as Low, 11 as Int, 25 as High and 12 Very High. The leukemic evolution occurred in 23 pts. The median leukemia free survival (LFS) was 825 days. Exitus occurred in 49 pts. The median overall survival (OS) was 902 days. We included in the study 20 controls (NC). METHODS: The MicroVessel Density (MVD) was evaluated through CD34 immuno-histochemical reactivity. Each BMB was first totally scanned at low magnification (10×) in order to identify 5 “hot spot” zones and then examined at high magnification (40×). MVD was estimated by hot-spot “method” (MVD-HS) by counting all of the positive-endothelial cells. Lumens were required to consider a structure as microvessel. Sinusoid-like structures, with the exception of arterioles, were also included in the count. To avoid any bias related to BMB cellularity, we calculated a VEGF expression index (VEGFi), defined as the cellularity of the BMBs multiplied by the fraction of VEGF positive cells and expressed as a number between 0 and 1 [(% of BMB cellularity × %VEGF-positive cells)/10⋀4]. Two VEGFi expression classes, respectively Low and High (L-VEGFi and H-VEGFi), were determined considering as cut-off level the mean VEGF(i) expression value + 2 standard deviations. RESULTS: MVD-HS analysis showed increased levels in MDS in comparison to NCs (p=.009). MVD did not differ among IPSS and WPSS categories. MVD did not predicted leukemia free and overall survival (LFS and OS). VEGF expression in bone marrow cells was found as a weak cytoplasmic granular protein expression in proeritroblasts; normoblasts were not immunoreactive. In the myeloid lineage VEGF expression was more intense in immature cells. The macrophages and megakaryocytes showed a granular weak cytoplasmic positivity. The plasmacells showed an intense granular cytoplasmic positivity. VEGFi expression was evenly distributed among the different IPSS and WPSS categories and was higher in MDS in comparison to NCs (p=.006). L-VEGFi MDS pts presented a significant lower transfusional need in the first years from diagnosis (p=.02). We observed that L-VEGFi MDS pts had a longer LFS compared with H-VEGFi ones (p=.006). Moreover, L-VEGFi MDS pts had a significant better OS compared to H-VEGFi pts (p=.03). At multivariate analysis IPSS and WPSS, as expected, predicted OS (p CONCLUSIONS: We show that in MDS pts at diagnosis bone marrow VEGFi evaluation predicts OS and LFS. The influence of VEGFi on LFS is retained also in multivariate analysis in a model including IPSS and WPSS. This finding is even more interesting considering that IPSS and WPSS are multiparametric score systems, and that WPSS necessitates the quantification of the transfusional need in the first months from diagnosis, while VEGFi is a single immunohistochemical parameter evaluated on BMB specimens at diagnosis. Further studies are warranted to confirm the prognostic role of VEGFi in this disease setting and its clinical implications. Disclosures: No relevant conflicts of interest to declare.

Abstract 4250 Background and Aims. Iron overload is frequently occurring in patients with myelodysplastic syndromes (MDS), with recent data suggesting an impact on both overall and leukemia-free survival1,2. Though prolonged RBC transfusion therapy appears the main contributor, many patients develop iron overload at an early stage of the disease, before the onset of transfusion dependency. It has been postulated that an altered production of hepcidin, the key hormone regulating iron homeostasis, may play a role at this regard. Until recently, studies have been hampered by problems in the development of reliable hepcidin assays, so that only scanty and conflicting data based on semi-quantitative measurement of urinary hepcidin have been reported3,4. This study mainly focused on analyzing serum hepcidin levels in MDS patients by means of a recently validated and improved Mass-Spectrometry based method5. Patients and Methods. One hundred and thirteen consecutive patients (mean age 72.8 ± 9.2 years; 68.1% males) with different types of MDS according to the WHO classification were included in this study. To be enrolled, patients had to be previously untreated or treated only with transfusions. Besides hepcidin, in all subjects we determined serum ferritin, transferrin saturation (TS), non-transferrin-bound-iron (NTBI), along with some putative determinants of hepcidin, like GDF-156 known to be associated with ineffective erythropoiesis, and C-Reactive Protein (CRP) as a surrogate of systemic IL-6 production. Fifty-four healthy individuals (61.1% males) with rigorous definition of normal iron status were used as controls. Main Results. Biochemical markers of iron overload (ferritin and TS), but also CRP and GDF-15 were significantly higher in MDS patients than in controls, even when considering only non-transfused patients. Patients with RARS and the 5q- syndrome appeared as the most iron overloaded, having the highest levels of ferritin, TS, and NTBI. In the whole MDS population, serum hepcidin levels showed a considerable variability, with overall mean values not significantly different from controls [geometric means (gm) with 95% CIs: 5.31 (3.98-7.08) versus 4.2 (3.53-5.0) nM, P=0.28], while the hepcidin/ferritin ratio was significantly lower than in controls [10.1 (7.53-13.53) versus 52.9 (43.6-64.3), P Conclusions. Hepcidin levels are consistently heterogeneous in MDS according to different subtypes, likely as the result of the relative strength of competing stimuli. Relative inhibition by ineffective erythropoiesis (but not mediated by GDF-15) seems to prevail particularly in RARS and 5q- syndrome, and is likely to increase the risk of iron overload in these subgroups. On the other hand, patients with RAEB 1–2 and CMML appears to have hepcidin induction that could be driven by cytokines. If confirmed, these results may be relevant not only for a better understanding of iron pathophysiology in MDS, but also for possible future approach with hepcidin modulators7. References: 1) Sanz G, et al. Blood 2008;112: abs 640. 2) Alessandrino EP, et al. Haematologica 2010;95:476-84. 3) Winder A, et al. Br J Haematol 2008;142:669-71. 4) Murphy PT, et al. Br J Haematol 2009;144:451-2. 5) Campostrini N, et al. J Biomed Biotechnol 2010;2010:329646. 6) Tanno T, et al. Nat Med 2007;13:1096-101. 7) Sasu BJ, et al. Blood 2010;115:3616-24. Disclosures: No relevant conflicts of interest to declare.

Abstract 1835 Defective apoptosis has a central role both in development and progression of chronic lymphocytic leukemia (CLL). Indeed in this hematological malignancy the expression of inhibitor of apoptosis proteins (IAPs) has been shown to be significantly up-regulated. The most potent among IAPs is probably the X-linked IAP (XIAP), which is characterized by three highly conserved tandem BIR domains (BIR1-3) able to block various members of the family of cysteine proteases (caspases) known as the main effectors of the apoptotic process. BIR3 domain selectively targets caspase 9, an initiator caspase, whereas the linker region between BIR1 and BIR2 binds with executioner caspases 3 and 7, thus inhibiting the activity of both initiator and effector of apoptosis. Smac-DIABLO (Second Mitochondria-derived Activator of Caspases - Direct IAp Binding protein with LOw pI) is a protein released from the mitochondria antagonizing the activity of XIAP. Therefore, small molecules mimicking Smac (Smac-mimetics) can induce apoptosis in tumor cells by displacing the interaction between XIAP and caspases. At the University of Milan, Center for biomolecular Interdisciplinary Studies and Industrial applications (CISI), new cell permeable Smac-mimetic compounds (monomers and dimers) binding to XIAP with high affinity were recently synthetized. Here we report the activity of a selection of these new agents in human lymphocytes from 32 CLL patients and from 6 healthy controls. The patient population included only subjects with active disease (11 females and 21 males; median age 72 years; Rai-Binet stage 0-A to II-B), who, at the time of samples collection, were either untreated or out of therapy since several months. Patients were characterized for the mutational IGVH status, cytogenetics (by FISH analysis), and the expression of both CD38 and ZAP 70. Following isolation from peripheral blood samples by density gradient centrifugation, mononuclear cells were treated for 16 hours at 37°C and 5% CO2 with low micromolar concentrations (1-10 microM) of a selection of our new Smac mimetic compounds, including 4 monomers (34, 55, 66 and 73), and 2 dimers (83, 85) which were have been previously shown to be active in leukemic cell lines overexpressing XIAP. Combination treatments with the proteasome inhibitor bortezomib (10nM) and with Tumor necrosis factor-Related Apoptosis-Inducing Ligand (TRAIL) (50 ng/ml) were also tested. Apoptosis rate was evaluated by flow cytometric analysis following annexin V and propidium iodide staining. Overall, the monomers were more cytotoxic than the dimeric compounds on leukemic cells. The most active agent was the monomer Smac66, which, after 16 hours of treatment at a 10 microM concentration promoted apoptosis in up to 72,5% (median value 40% ranging from 11% to 72,5%) of CLL lymphocytes. In comparison to normal lymphocytes from healthy controls, where the median rate of apoptosis was 10.1% (range1.2% to 18%), the cytotoxic effect of the Smac66 compound was significantly higher (p=0.0004) in CLL cells. No synergistic effect was observed in combined treatment with bortezomib nor with TRAIL. Rate of apoptosis did not correlate with clinical parameters, cytogenetics, mutational IGVH status, and expression of CD38 and ZAP70 was observed, but the limited size of our patient population should be taken into account. In conclusion, among our Smac mimetics selected molecules seem be very active in CLL lymphocytes, suggesting a promising therapeutic potential in this malignancy. Further molecular investigations as well as in vivo studies in animal models are currently ongoing respectively to better elucidate the mechanism of action of these compounds and to promote their preclinical development. Disclosures: No relevant conflicts of interest to declare.

Abstract 1752 Poster Board I-778 Iron overload (IO) occurs in a large proportion of patients affected by myelodysplastic syndromes; however data on the mechanisms responsible for IO and on the consequences on organ damages are scanty. IO in MDS may result both from ineffective erythropoiesis and from reiterative transfusions. The role of iron chelation therapy in MDS is deduced from thalassemia experience. We evaluated parameters of iron metabolism and erythropoiesis in 171 consecutive chelation naïve MDS patients. Patients were classified according WHO criteria, and prognostic scores evaluated according IPSS and WPSS criteria. CMML patients (n= 7) were also included in the analysis. Serum ferritin, iron, transferrin, transferrin saturation and non-transferrin-bound iron (NTBI) were measured. Growth-differentiation factor-15 (GDF-15) and hepcidin-25 were also determined, parallel to hemoglobin, endogenous erythropoietin (EPO) and LDH. All the parameters studied were highly variable within the analyzed cohort, as expected due to the great heterogeneity of MDS. As already observed, ferritin levels were higher than normal range in MDS patients (1091 ± 1135 ng/ml) and significantly increased in transfused ones (1890,55 ± 1833 ng/ml). EPO production was stimulated in all MDS patients (215, 40; range 85-1011 U/L), respect to normal range, and physiologically inversely correlated with hemoglobin levels (p Disclosures No relevant conflicts of interest to declare.

Abstract 4379 Background Toll-like receptors (TLRs) are major agents of innate immunity and initiators of adaptive immune response by acting as costimulatory signals for B cells and inducing maturation, proliferation and antibody production after pathogen recognition. They are also involved in the self-antigen recognition and could play a role in autoimmune phenomena. It is well known that chronic lymphocytic leukemia (CLL) is characterized by an increased incidence of autoimmune phenomena and immunodeficiency, which can greatly influence the disease outcome leading to a variable clinical course. Aims To evaluate the correlation between the gene expression of TLRs in 41 patients with CLL (mean age±SD 66±18 years, range 42-90, 15 female and 26 male), the clinical course of the disease and the expression of prognostic factors (mutational status of IgVH region, CD38 and ZAP70 expression, and cytogenetic alterations). Methods The gene expression of TLR4, TLR9, and TLR10 was studied. Total RNA was extracted from B cells of patients and controls (pool of 10 healthy donors), cDNA was synthesized, and real-time PCR was performed. For each reaction 50 ng of cDNA were mixed with 1.25μl of TaqMan primer/probe set and 10.25μl of TaqMan Universal Master Mix. The TLR4, TLR9, and TLR10 expression was normalized according to GAPDH as an internal control gene and it was expressed as percentage of control. Results TLR4 gene expression was significantly lower in CLL patients compared to controls (18±3%, mean±SE) while TLR9, and TLR10 gene expression was higher (3457±500% and 2897±440%, respectively). Moreover, considering “progressive” CLL patients (n=20), TLR4 gene expression was significantly lower compared with “indolent” ones (n=21) (10.2±2.2% vs 24.9±4.9%, p=0.01). Patients with unmutated IgVH expression and unfavorable cytogenetic alterations (mostly 11q-) showed even more reduced TLR4 gene expression, but the small numbers did not allow statistical evaluation. TLR4 gene expression was lower in patients with infective diathesis, although not significantly (11.5±2.9% vs 20.0±3.9).The 6 “progressive” CLL patients with autoimmune diseases (hemolytic anemia, Evan's syndrome and phemphigus) showed significantly higher TLR4 gene expression compared with “progressive” patients without autoimmune phenomena (17.7±4.4% vs 6.9±2.1%, p=0.02), possible expression of activated immune system. Conclusion The reduced TLR4 gene expression in CLL patients with “progressive” disease, unmutated IgVH status, and unfavourable cytogenetic alterations is consistent with a reduced ability to a proper immune response to Gram-negative bacterial lipopolysaccarides and consequent increased susceptibility to infections. Disclosures: No relevant conflicts of interest to declare.