Abstract: Recent evidence suggests that the prognostic impact of gene mutations in patients with chronic lymphocytic leukemia (CLL) may differ depending on the immunoglobulin heavy variable (IGHV) gene somatic hypermutation (SHM) status. In this study, we assessed the impact of nine recurrently mutated genes ( BIRC3 , EGR2 , MYD88, NFKBIE , NOTCH1 , POT1 , SF3B1, TP53 , and XPO1 ) in pre-treatment samples from 4580 patients with CLL, using time-to-first-treatment (TTFT) as the primary end-point in relation to IGHV gene SHM status. Mutations were detected in 1588 (34.7%) patients at frequencies ranging from 2.3–9.8% with mutations in NOTCH1 being the most frequent. In both univariate and multivariate analyses, mutations in all genes except MYD88 were associated with a significantly shorter TTFT. In multivariate analysis of Binet stage A patients, performed separately for IGHV-mutated (M-CLL) and unmutated CLL (U-CLL), a different spectrum of gene alterations independently predicted short TTFT within the two subgroups. While SF3B1 and XPO1 mutations were independent prognostic variables in both U-CLL and M-CLL, TP53 , BIRC3 and EGR2 aberrations were significant predictors only in U-CLL, and NOTCH1 and NFKBIE only in M-CLL. Our findings underscore the need for a compartmentalized approach to identify high-risk patients, particularly among M-CLL patients, with potential implications for stratified management.

Abstract: 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. & lt;6), CLL treatment history, details regarding COVID-19 course, management, and therapy, and vital status were collected. 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 & lt; 1.0 x 109/L; 18% vs. 28%), while others varied between Co1 and Co2 (p & lt;0.0001), including cough (61% vs. 93%), dyspnea (60% vs. 84%), fatigue (13% vs. 77%). 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 & lt;0.0001). Figure 1 depicts OS in each cohort. Univariable analyses demonstrated that age and CIRS ≥6 significantly predicted inferior OS in both cohorts, while only age remained an independent predictor of inferior OS in multivariable analyses (Table 2). Prior treatment for CLL (vs. observation) predicted inferior OS in Co1 but not Co2. 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.

Abstract: Introduction. Ibrutinib is a first-in-class, oral, once-a-day Bruton's tyrosine kinase inhibitor that achieves high overall response rates and durable remissions in patients with chronic lymphocytic leukemia (CLL) including those with high-risk features (unmutated IGHV, TP53 abnormalities, 11q deletion). Survival with continuous single-agent ibrutinib in previously-untreated CLL patients is comparable to an age-matched general population (Figure 1). IBRORS is an observational, retrospective, multicentre study to describe the characteristics and clinical outcomes of patients with CLL treated with single-agent ibrutinib in routine clinical practice in Spain. This present analysis reviews the subset of patients in IBRORS who received ibrutinib as the first-line of treatment. This series includes a significant number of patients with high risk cytogenetic/molecular alterations (del17p/TP53 M), which corresponds with the approved indication for first-line CLL patients in Spain at the time. Methods. Adult patients diagnosed with CLL treated with single-agent ibrutinib in first-line, or at first or second relapse since its commercialization in Spain (between January 2016 to January 2019) were included in the IBRORS study. Clinical characteristics of patients, efficacy and tolerability of ibrutinib as first-line treatment were analyzed here. A Kaplan-Meier analysis was performed for overall survival (OS) and progression-free survival (PFS). Results. 84 patients, from a total of 269 included in IBRORS, received single-agent ibrutinib as first-line treatment. The median age was 71.3 years (range 63-77) at the time of ibrutinib initiation. 56.3% of patients presented with an intermediate/high-risk Rai-Binet stage, and the majority of patients (98.6%) had an ECOG PS of 0-1. 91.7% of patients had at least 1 high risk molecular cytogenetic factor (unmutated IGHV, TP53 abnormalities, 11q deletion or complex karyotype) described in table 1. Baseline comorbidities of patients are described in table 2. Concomitant medication included anticoagulants (9.5% patients; vitamin K antagonist [n=4], Apixaban [n=1] and LMWH [n=3] patients), antiplatelet agents (11.9% patients), and antihypertensives (50% patients). The overall response rate (ORR) was 79.5%; 14/84 (16.6%) achieved a complete response (CR), 14/84 (16.6%) achieved CR unconfirmed, 27/84 (32.14%) achieved a partial response (PR) and 12/84 (14.2%) a PR + lymphocytosis. The median PFS and OS were not reached, and the estimated PFS at 24 months was 84.5% (73.4-95.6%). OS and PFS curves are represented in figure 2. The PFS of each patient subgroup with high-risk cytogenetic characteristics was similar to that of all patients in the first-line cohort: del17p/TP53 mutation (HR = 0.963 [95% CI 0.188-4.928]; p = 0.964), del11q (HR = 0.042 [95% CI 0.000-682.736] ; p=0.521), unmutated IGHV (HR = 0.391 [95% CI 0.110-1.394]; p = 0.148). The median duration of exposure to ibrutinib was 17.3 (11.9-25.6) months. Dose reduction of ibrutinib occurred in 17/84 (20.2%) patients, 8/84 (9.52%) due to toxicity (4 hematologic toxicity and 4 non-hematologic toxicity). 27/84 (32.1%) patients had temporary interruption of treatment. 15/84 (17.8%) patients permanently discontinued ibrutinib including 6 (7.14%) patients due to progression, 4 (4.76%) due to toxicity and 5 for other reasons. Safety: 49/84 (58.3%) patients developed at least one adverse event (AE), while 12/84 (14.2%) patients developed at least one serious adverse event (SAE). Twelve (14.3%) patients reported at least one haematological toxicity while 53 patients (63.1%) recorded at least one non-haematological toxicity. Only 1 patient experienced grade 3 atrial fibrillation, which did not lead to discontinuation. The most common AEs are described in table 3. Conclusion. This population of previously-untreated CLL patients, enriched for high-risk genomic features, reflects the initial approval of ibrutinib for the treatment of first-line patients with del17p in Spain. Single-agent Ibrutinib as the first-line treatment in this real world population was effective regardless of risk factors and well tolerated, with a low rate of discontinuation due to toxicity. Findings are consistent with those reported in clinical trials. Disclosures Loscertales: AbbVie: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; AstraZeneca: Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria. Arguiñano:AbbVie: Honoraria; Janssen: Honoraria; BMS-Celgene: Honoraria; Novartis: Honoraria. Hernandez-Rivas: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; 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; Rovi: Membership on an entity's Board of Directors or advisory committees. Pérez Persona:Amgen: Consultancy; Celgene: Consultancy, Speakers Bureau; Roche: Consultancy, Speakers Bureau; Jannsen: Consultancy, Speakers Bureau; Abbvie: Consultancy, Speakers Bureau; Takeda: Consultancy. Loriente:Janssen Cilag: Current Employment. Villanueva:Janssen Cilag: Current Employment.

Abstract: NKX2 homeobox family proteins have a role in cancer development. Here we show that NKX2 - 3 is overexpressed in tumour cells from a subset of patients with marginal-zone lymphomas, but not with other B-cell malignancies. While Nkx2-3 -deficient mice exhibit the absence of marginal-zone B cells, transgenic mice with expression of NKX2-3 in B cells show marginal-zone expansion that leads to the development of tumours, faithfully recapitulating the principal clinical and biological features of human marginal-zone lymphomas. NKX2-3 induces B-cell receptor signalling by phosphorylating Lyn/Syk kinases, which in turn activate multiple integrins (LFA-1, VLA-4), adhesion molecules (ICAM-1, MadCAM-1) and the chemokine receptor CXCR4. These molecules enhance migration, polarization and homing of B cells to splenic and extranodal tissues, eventually driving malignant transformation through triggering NF-κB and PI3K-AKT pathways. This study implicates oncogenic NKX2-3 in lymphomagenesis, and provides a valid experimental mouse model for studying the biology and therapy of human marginal-zone B-cell lymphomas.

Abstract: BACKGROUND Patients with relapsed or refractory diffuse large B-cell lymphoma (DLBCL), non-candidates for autologous stem-cell transplantation (ASCT), have few treatment options. Ibrutinib is an oral Bruton's tyrosine kinase inhibitor that has shown increased antitumor activity in patients with DLBCL of different subtype from germinal center B-cell like (non-GCB). In the present phase II clinical trial (NCT02692248), we investigated the efficacy and toxicity of the combination of Ibrutinib with the R-GEMOX-D regimen (rituximab, gemcitabine, oxaliplatin and dexamethasone), in patients with non- GCB DLBCL. METHODS We included patients with histological diagnosis of non-GCB DLBCL (according to Hans algorithm), with relapsed or refractory disease after at least 1 line of immunochemotherapy and non-candidates for ASCT. Patients received an induction treatment consisting of 6 (in case of complete remission [CR] after cycle 4) or 8 (in case of partial response [PR] or stable disease after cycle 4) cycles of R-GEMOX-D at standard doses every 2 weeks, in combination with ibrutinib (560 mg daily), followed by a maintenance treatment with ibrutinib for a maximum of 2 years. The primary objective was to evaluate the overall response rate (ORR) after 4 cycles, and the secondary objectives were: CR rate, progression-free survival (PFS), overall survival (OS) and toxicity. Analyses were performed in the intention to treat population (data cut-off 10th April 2020). RESULTS Sixty-four patients (59.4% male) were included between March 2016 and November 2018. Median age was 67 (25-84) years. Patients had received a median of 2 previous lines of treatment; 56.3% were refractory ( & lt;PR) to the last regimen, whereas 43.7% had relapsed disease after a previous CR. Eleven (17.2%) patients had received a previous ASCT. IPI at study entry was 0-1, 2-3, and 4-5 in 9.4%, 67.2%, and 20.3% of patients, respectively (missing data in 2 patients). Of the 64 patients who started study treatment, 44 and 35 patients, respectively, were evaluated for response after 4th cycle and at the end of induction. Twenty-four (37%) patients started maintenance with ibrutinib, 7 of whom continue or have completed it. Causes of withdrawal from the trial (n=57) were progression (n=40), adverse event (n=6), transplantation (n=5), withdrawal of consent (n=3) and other causes (n=3). ORR and CR rate after 4th cycle were 53.2% and 35.9%, respectively. Patients with relapsed disease had significantly higher ORR (67.9% vs 41.7%, p=0.037) and CR rate (57.1% vs 19.4%, p=0.002) than patients with refractory disease. At the end of induction, ORR and CR rate were 35.9% and 29.7%, respectively. After a median follow-up of 22 months (range: 1 to 39 months), the estimated 2-year PFS and OS were 21% and 25%, respectively (Figure 1A and 1B), being significantly better in patients with relapsed disease (Figure 1C and 1D). In the multivariate analysis, status of lymphoma at study entry significantly influenced PFS (HR 0.45; 95% CI 0.25-0.82; p=0.009) and OS (HR 0.51; 95% CI 0.27-0.94; p=0.0031) independently from the IPI and the number of previous treatment lines. The most frequent adverse events (AE) (present in at least 20% of patients) were thrombocytopenia (67.2%), diarrhea (51.6%), neutropenia (46.9%), anemia (37.5%), fatigue (34.4%), nausea (29.7%) and paresthesia (20.3%). The most frequent grade 3-5 AE (present in at least 10% of patients) were thrombocytopenia (46.9%), neutropenia (35.9%), diarrhea (15.6%) and anemia (14.1%). Three patients presented a grade 5 AE, two of them related (aspergillosis and pneumonia, respectively) and one unrelated (heart failure). CONCLUSIONS The combination of ibrutinib with R-GEMOX-D as salvage therapy for patients with non-GCB DLBCL is associated with high response rates, especially in relapsed patients. The vast majority of refractory patients progress very early, so this regimen could be considered as a bridge to other consolidation therapies. Biological studies analyzing cell of origin by gene expression profiling, minimal residual disease and mutational spectrum are in progress. Disclosures Abrisqueta: Roche: Consultancy, Honoraria, Speakers Bureau; Celgene: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Speakers Bureau; AbbVie: Consultancy, Honoraria, Speakers Bureau. Giné:Janssen: Research Funding; Gilead: Research Funding; Roche: Research Funding. Grande:Janssen: Research Funding. Caballero:Roche: Other: travel; Gilead: Other: travel; Celgene: Membership on an entity's Board of Directors or advisory committees, Other: travel; Janssen: Membership on an entity's Board of Directors or advisory committees, Other: travel; BMS: Other: travel; Takeda: Other: travel; Kite: Membership on an entity's Board of Directors or advisory committees. Martin Garcia-Sancho:Roche, Celgene, Janssen, Servier, Gilead: Honoraria; Celgene, Eusa Pharma, Gilead, iQuone, Kyowa Kirin, Roche, Morphosys: Consultancy. OffLabel Disclosure: Off-label use of a new combination in the context of a clinical trial. New combination (Ibrutinib + R-GEMOX)

Abstract: Background and objective. Specific immunochemotherapy is the standard treatment of patients with Burkitt leukemia or lymphoma (BL/L). The BURKIMAB08 trial showed 3-yr overall survival (OS) probability of 72% (Ribera JM et al, Cancer. 2013; 119:1660-8). However, the toxicity was high, and 11% of patients died in complete response (CR). In the BURKIMAB14 trial, dose-intensity of chemotherapy blocks was reduced in patients ≤55 years who achieved CR, with the aim to decrease the death rate without impact on efficacy. We present the results of this trial in 80 patients with BL/L and compare them with those of the BURKIMAB08 trial. Patients and method. All patients received a pre-phase with cyclophosphamide, prednisone and rituximab. Patients in localized stages (I-II non-bulky) received 4 blocks of immunochemotherapy (A1, B1, C1, A2), with 33% reduction of doses of iphosphamide, methotrexate and ARA-C in patients ≤55 years in CR (assessed by PET-CT) after B1 cycle. Patients in stages III-IV and mature B-ALL received 6 immunochemotherapy blocks (A1, B1, C1, A2, B2, C2), with the same dose reduction in cycles C1, A2, B2, C2 in patients ≤55 years in CR after B1 cycle. Patients 〉 55 years received reduced intensity chemotherapy (as in BURKIMAB08) in both induction and post-induction cycles. The CR rate, cumulated incidence of relapse (CIR) and OS were analyzed and compared with those from the BURKIMAB08 trial. Results. From 2014-2019, 80 patients with BL/L were enrolled. Median age (range): 48 (17-80) years, 57 (71%) ≤55 years, 61 males (76%), 15 (19%) patients in stages I-II non-bulky and 65 (81%) in stages III-IV, 25 of whom (38%) had mature B-ALL. 18 patients (23%) were HIV positive, 13 (17%) showed CNS involvement at diagnosis and 23 (31%) bulky mass ( 〉 10 cm). 45 patients (60%) had intermediate-high or high IPI. All patients in stages I-II non-bulky showed CR. 4/65 patients in stages III-IV or mature B-ALL are receiving induction therapy, 1/65 withdrew the trial, 7/60 (12%) died in induction, 2/60 (3%) were resistant and 51/60 (85%) achieved CR. Of them, 6 relapsed, 3 withdrew the trial and 3 died in CR (one in the group of localized stage). OS probability at 3 years was 74% (95%CI: 64%-84%) (localized stages 100% [NE], advanced stages 68% [56%-80%] , p=0.047, without difference in patients in stages III-IV vs. mature B-ALL, Figure 1). Patients 〉 55 years showed a significantly lower probability of OS (61% [41%-81%] vs. 80% [68%-92%] , p=0.022, Figure 2). A lower but non-statistically significant OS probability was observed in HIV-infected vs. non-HIV-positive patients (61% [36%-86%] vs. 78% [67%-89%] , p=0.310). The CIR for patients in advanced stage/mature B-ALL was 13% (3%-28%)A trend for lower death rate in CR was observed in BURKIMAB14 vs. BURKIMAB 08 trial (3/62 vs. 16/151, p=0.180), without differences in CIR (9% [3%-21%] vs. 12% [6%-20%] ) or in OS (74% [64%-84%] vs. 72% [65%-79%] , respectively). Conclusions. The results of the BURKIMAB14 trial are promising, especially for patients in localized stages and for those 〈 55 years. The death rate in CR was lower compared with the BURKIMAB08 trial. The reduction of the dose-intensity of chemotherapy in CR patients did not have impact on the CIR. Supported in part with the grants PI14/01971 FIS, Instituto Carlos III, SGR 288 (GRC) y Fundación "La Caixa". Figure 1. OS according to stage (I-II, vs. III-IV vs. mature B ALL) Figure 2. OS according to age (≤55 y vs 〉 55 y) Figure 1 Disclosures Abrisqueta: Abbvie: Consultancy, Honoraria, Other: Travel, Accommodations, expenses, Speakers Bureau; Celgene: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Other: Travel, Accommodations, expenses, Speakers Bureau; Roche: Consultancy, Honoraria, Other: Travel, Accommodations, expenses, Speakers Bureau. Fernandez:Teva: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Incyte: 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, Research Funding, Speakers Bureau; Abbvie: Membership on an entity's Board of Directors or advisory committees; Daiichi Sankyo: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Celgene: Consultancy, 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, Research Funding, Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Karyopharm: Membership on an entity's Board of Directors or advisory committees, Research Funding. Terol:Roche: Consultancy; Abbvie: Consultancy; Astra Zeneca: Consultancy; Janssen: Consultancy, Research Funding; Gilead: Research Funding. Gimeno Vázquez:JANSSEN: Consultancy, Speakers Bureau; Abbvie: Speakers Bureau. Sancho:Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Gilead: Consultancy, Honoraria, Other: Advisory board; Novartis: Honoraria; Kern Pharma: Honoraria, Membership on an entity's Board of Directors or advisory committees; Sanofi: Honoraria; Celltrion: Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squib: Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Sandoz: Consultancy; F. Hoffmann-La Roche Ltd: Honoraria, Membership on an entity's Board of Directors or advisory committees.

Abstract: Introduction: The negative minimal residual disease (MRD) after treatment has been recently accepted as endpoint for Chronic Lymphocytic Leukaemia (CLL) clinical trials. Conventionally, MRD can be detected by using multi-color Flow Cytometry (FC) with high sensitivity. Determination of the clonal immunoglobulin gene rearrangement can be a useful monitoring marker in a broad range of B-cell lymphoproliferative neoplasms. Moreover, the mutational status of immunoglobulin heavy chain variable (IgHV) rearrangement is considered one of the most important prognostic factors in CLL. Therefore, the identification of the IgHV rearrangement can be a useful marker both at diagnostic and as monitoring marker for MRD. Nowadays, high-throughput sequencing (HTS) technologies has enabled highly sensitive cancer genomic testing in clinical laboratories. There are same initiatives based on HTS to use IgHV rearrangement as marker for MRD monitoring in Acute lymphoblastic leukemia or multiple myeloma, but it remains unharmonized for application on CLL in the clinical laboratory. Objective: We evaluated the performance and clinical applicability of HTS assay for IgHV rearrangement in CLL MRD monitoring in 69 samples from 19 CLL patients treated. Methods: The libraries including IGH locus were performed using the Sequencing Multiplex Kit on IGH consensus primers. To simplify and make automatic the analysis of the data obtained, we developed a specific bioinformatic pipeline that covers from preprocessing to final data summarization and interpretation. The backbone of the analysis includes read preprocessing, mapping against IMGT reference sequences, consensus IgHV reads pairwise alignment to determine mutational status and read classification into rearrangements. Assessment of IgHV mutational status by Sseq, genomic DNA (gDNA; 50-100 ng), were used for IgHV analysis. gDNA was amplified using locus-specific primer sets for IgHV designed to allow for the amplification of all known alleles of the germline IgH sequence, as described previously. Inmunophenotypic studies were performed on erythrocyte-lysed whole PB samples according to Euroflow procedures. PB white blood cells (WBC) was systematically stained with the eight color combination panel recently proposed by the ERIC group for MRD detection (Rawstron AC et al. 2016). Data acquisition was performed on a FACSCanto II flow cytometer Becton-Dickinson Biociences using the FACSDiva software (V8.0; BD). For data analysis, the Infinicyt softwareTM (Cytognos SL, Salamanca, Spain) was used. The MRD levels were reported as fraction of CLL cells of all nucleated cells. MRD negativity was define as a fraction 〈 10 -4 However, for treatments that preferentially clear the blood (for example monoclonal antibodies) the MRD was confirm in the bone marrow as has been recommended. Results: Patient demographics and the results of IGH clonality tests are summarized in Table 1. Interpretable results were obtained with higher sensitivity compared with Sseq at diagnosis stage (19/19 samples), and we are able to determine the same clone at subsequent samples. Among 50 follow-up samples, 44 MRD were positive in both techniques (HTS and FC); 3 follow-up samples, were negative in both determinations (HTS and FC); in contrast, 3 follow-up samples, were negative by FC but positive by HTS (8.3, 17.2, 18.2 samples). This is the case of Patient 8, in which the last follow-up sample, the detection of the primary clone is positive by HTS, while by FC is undetected (Figure 1). In addition, it was possible to detect IgHV clone in all Patient 7 samples. It was under long-term monitoring by HTS and FC, and 17 months after initial diagnosis and first line of treatment (7.5 sample), it was detected a loss of response (Figure 2.). Conclusions: We evaluated an HTS IgHV assay using initial and follow-up samples of 19 CLL patients. Using our pre-designed primer set in library preparation, and developed our specific bioinformatic pipeline that covers from preprocessing to final data summarization and interpretation, we were able to demonstrate that our method was more sensitive than FC in detecting positive follow-up samples and could be able to propose it for MRD monitoring in CLL. However, the prognostic impact of these low-level MRD detected by HTS should be validated with further investigations. Samples were provided by the INCLIVA Biobank. Funded by Gilead Felowship 257/17 Disclosures Ortiz: GILEAD SCIENCES: Research Funding. Terol:Abbvie: Consultancy; Gilead: Research Funding; Janssen: Consultancy, Research Funding; Astra Zeneca: Consultancy; Roche: Consultancy.

Abstract: Abstract 3949 Although in MM an optimal response to front-line therapy is a surrogate for extended survival, two class of patients fall outside this paradigm: those that after treatment show unsustained complete remission (CR) and those that not achieving CR, return into an MGUS-like signature and experience nevertheless long term disease control (LTDC). The prospective identification of the later group remains to be accomplished. Herein, we hypothesized that whole BM immunophenotypic profiling by multiparameter flow cytometry (MFC) would help to identify upfront, symptomatic MM patients with an occult MGUS-like signature (from here on named MGUS-like-MM). For this purpose, the relative frequency of plasma cells (plus the balance between clonal and normal PC), precursor and mature B-cells, T- and NK-cells, erythroblasts, monocytes, neutrophils and eosinophils was determined in 698 newly diagnosed, transplant eligible MM patients included in two consecutive GEM/PETHEMA trials: GEM2000 (VBMCP/VBAD; n=486) and GEM2005 〈 65y (randomized induction with the same chemotherapy plus bortezomib in the last two cycles or thalidomide/dexamethasone or bortezomib/thalidomide/dexamethasone followed by HDT/ASCT; n=212). In addition, we extended this analysis to 114 high-risk smoldering MM patients included in the Quiredex trial. Median follow-up was 63 months for symptomatic MM patients. Unsupervised hierarchical cluster analysis was used on the log2 transformed values of the 11 variables described above. Whole BM immunophenotypic profiling identified a cluster of 176 (25%) symptomatic MM patients “assigned as MGUS-like-MM” based on the following phenotypic features: significantly decreased median numbers of myelomatous PC together with a significant increment of eosinophils, neutrophils, monocytes, T- and NK -cells, mature B-cells and particularly normal PC. This subgroup was characterized by a favorable clinical presentation with increased (P 〈 .005) frequency of ISS stage I or II (88%), high baseline hemoglobin (116 g/L) and albumin (3.8 g/dL) values. MGUS-like-MM patients showed an increased frequency of hyperdiploid DNA content (63%; P=.001) and a lower incidence of t(4;14) (3%; P=.05). When compared to the overall population, MGUS-like-MM patients showed a markedly superior median TTP (88 vs 40 months; P 〈 .001) and OS (141 vs 61 months; P 〈 .001). Moreover, the MGUS-like signature was a strong predictor for LTDC, with 16% of these patients being disease-free at 10 years as compared to 3.5% in the overall MM population (P 〈 .001). Interestingly, while the depth of response achieved after HDT/ASCT translated into superior TTP (P=.032) and OS (P=.005) in the overall population, MGUS-like-MM patients failing to achieve CR showed non significantly different median TTP (80m vs 105m; P=.167) and OS (not reached vs 141m; P=.438) as compared to those attaining CR, respectively. Finally, it should be pointed out that this MGUS-like signature was not restricted to symptomatic MM, since we have also found a subset of high-risk smoldering MM patients with the same signature. These later patients showed a significantly lower risk of progression into symptomatic MM as compared to the rest of high-risk smoldering MM patients (data not shown). In summary, whole BM immunophenotypic profiling by MFC is capable to identify a subset of symptomatic MM patients with an occult MGUS-like signature associated with prolonged survival. Given that in this subgroup of patients the value of CR is not as important as in the rest of MM patients, the prospective identification of this signature may contribute to discriminate a sub-optimal response that require additional treatment from a residual “MGUS-like component” that may remain stable without further treatment. Disclosures: Paiva: Celgene: Honoraria; Miellenium: Honoraria; Janssen: Honoraria. Martínez-López:Celgene: Honoraria. Mateos:Celgene: Honoraria; Miellenium: Honoraria; Janssen: Honoraria. De La Rubia:Celgene, Janssen: Consultancy, Speakers Bureau. Lahuerta:Celgene: Honoraria; Millenium: Honoraria. Blade:Celgene: Honoraria; Millenium: Honoraria; Janssen: Honoraria. San Miguel:Celgene: Honoraria; Millenium: Honoraria; Janssen: Honoraria.

Abstract: Abstract 3 In elderly pts with newly diagnosed MM, the VISTA trial has demonstrated that the combination of bortezomib plus melphalan – prednisone (VMP) is significantly superior to MP alone. However, it remains to be elucidated which agent is the optimal partner for bortezomib: an alkylating agent or an immunomodulatory drug. In order to answer this question, Spanish Myeloma Group activated a phase III trial comparing VMP versus VTP (T for thalidomide) as induction therapy. To evaluate if the treatment regimen could be further optimized by decreasing the toxicity while maintaining efficacy, the intensity of both schedules of induction was reduced as compared with the VISTA regimen but supplemented with maintenance therapy. Between April 2005 and October 2008, 260 pts were randomized to receive 6 cycles of VMP vs VTP as induction therapy followed by maintenance with VT vs VP for up to three yrs. In the VMP arm pts received bortezomib 1.3 mg/m2 twice weekly (days 1, 4, 8, 11; 22, 25, 29 and 32) for one 6-week cycle, followed by once weekly (days 1, 8, 15 and 22) for five 5-week cycles in combination with oral melphalan 9 mg/m2 and prednisone 60 mg/m2 once daily on days 1–4 of each cycle. In the VTP arm pts received the same bortezomib and prednisone, but instead of melphalan they received thalidomide at a dose of 100 mg daily. Following the 6 cycles of induction, pts moved into maintenance that consisted in a conventional cycle of bortezomib, 1.3 mg/m2 twice weekly (days 1, 4, 8, 11) administered every three months in combination with either continuous thalidomide, 50 mg daily (VT) or prednisone, 50 mg on alternate days (VP). 253 pts are evaluable for response to induction; 125 were assigned to receive VMP and 128 to VTP. Regarding baseline characteristics, both arms were well balanced. Response rate to induction therapy was similar in both arms: ≥ PR in 81 and 79% of pts treated with VMP and VTP respectively, with a CR rate of 22% vs 27% (p=NS) and CR+nCR of 36% in both arms. Only two pts progressed under induction treatment in each arm. After a median follow-up of 22m (8-40), there weren't significant differences in terms of 2-y TTP (VMP 75% vs VTP 70%), PFS (VMP 71% vs VTP 61%) and OS (VMP 81% vs VTP 84%). 178 pts were randomized to maintenance and 143 are evaluable for efficacy. Overall, maintenance therapy was able to increase the CR rate from 25% (mean obtained after induction therapy) up to 42%, with no significant differences between VT and VP arms (46 and 38%). After a median duration of maintenance of 13 m there is a trend in favour of VT in terms of 1-y TTP (84% vs 71%; p=0.05), without differences in 1-y OS (92% for VT vs 89% for VP). 27 pts presented high-risk cytogenetic abnormalities (CA) ((4;14)t, (14;16)t, del[17p]); the CR rate was similar in this high-risk group as compared with standard risk group (26% vs 25% after induction and 42% after maintenance in both groups). There aren't differences between high-risk and standard-risk pts in the 2-y TTP (74% vs 73%) and 2-y OS (77% vs 81%) from inclusion; however, there is a trend to lower 1 y-TTP from the time to randomization to maintenance for the high-risk group compared to the standard-risk (68% vs 79%) without differences in 1 y-OS (90% vs 93%). Regarding toxicity, during the induction therapy, VMP resulted in higher incidence of ≥G3 neutropenia than VTP (37 vs 21%) and this translated into more ≥G3 infections (7 vs 〈 1%); 8,5% of pts receiving VTP developed ≥G3 cardiac events (cardiac failure (5), atrial fibrillation (2), hypotension (2), heart attack (1) and AV blockage (1)). The incidence of ≥G3 PN was 5% in VMP and 9% in VTP (p=NS). During maintenance therapy, the most relevant ≥G3 toxicities included: cardiac events in 2 pts in VT (supraventricular arritmia (1) and heart attack (1)) vs 1 in VP (cardiac failure); G-I events in 4 pts in VT vs 1 in VP; finally, only one patient in VT arm died during the maintenance therapy due to sepsis. In summary the current results indicate that: 1. both modified induction schedules (VMP and VTP) are highly effective with similar ORR and CR rates, but a clear different toxicity profile (more neutropenia, but less cardiac toxiciety and PN with VMP); 2. maintenance therapy with either VT and VP markedly improve the quality of responses with a good safety profile; and finally 3. the combination of these induction and maintenance schedules seems to overcome the poor prognosis of high-risk CA in elderly MM patients. Disclosures: Mateos: Janssen Cilag: Honoraria, Speakers Bureau; Celgene corporation: Honoraria, Speakers Bureau. Off Label Use: VTP is not approved for the treatment of untreated MM patients. Cibeira:Jansen-Cilag: Honoraria; Celgene: Honoraria. Gutiérrez:Janssen Cilag: Honoraria; Celgene: Honoraria. García-Laraña:Janssen-Cilag: Honoraria; Celgene: Honoraria. Palomera:Janssen-Cilag: Honoraria; Celgene: Honoraria. de Arriba:Janssen-Cilag: Honoraria; Celgene: Honoraria. San-Miguel:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Millennium: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen–Cilag: Honoraria, Membership on an entity's Board of Directors or advisory committees.