Abstract: The need for allogeneic hematopoietic stem cell transplantation (allo-HSCT) in adults with Philadelphia chromosome–negative (Ph−) acute lymphoblastic leukemia (ALL) with high-risk (HR) features and adequate measurable residual disease (MRD) clearance remains unclear. The aim of the ALL-HR-11 trial was to evaluate the outcomes of HR Ph− adult ALL patients following chemotherapy or allo-HSCT administered based on end-induction and consolidation MRD levels. Patients aged 15 to 60 years with HR-ALL in complete response (CR) and MRD levels (centrally assessed by 8-color flow cytometry) & lt;0.1% after induction and & lt;0.01% after early consolidation were assigned to receive delayed consolidation and maintenance therapy up to 2 years in CR. The remaining patients were allocated to allo-HSCT. CR was attained in 315/348 patients (91%), with MRD & lt;0.1% after induction in 220/289 patients (76%). By intention-to-treat, 218 patients were assigned to chemotherapy and 106 to allo-HSCT. The 5-year (±95% confidence interval) cumulative incidence of relapse (CIR), overall survival (OS), and event-free survival probabilities for the whole series were 43% ± 7%, 49% ± 7%, and 40% ± 6%, respectively, with CIR and OS rates of 45% ± 8% and 59% ± 9% for patients assigned to chemotherapy and of 40% ± 12% and 38% ± 11% for those assigned to allo-HSCT, respectively. Our results show that avoiding allo-HSCT does not hamper the outcomes of HR Ph− adult ALL patients up to 60 years with adequate MRD response after induction and consolidation. Better postremission alternative therapies are especially needed for patients with poor MRD clearance. This trial was registered at www.clinicaltrials.gov as # NCT01540812.

Abstract: Introduction In the first weeks of the Covid-19 pandemic when healthcare systems in many areas were overstretched, we documented that hospital mortality in multiple myeloma (MM) patients infected by Sars-Cov-2 was 50% higher than in age matched Covid-19 patients without cancer. In the following months, the pressure on healthcare systems in Spain continued although it did not reach the extreme levels of the first weeks of the pandemic. In this study, we proposed to determine if the severity of Covid-19 outcomes in MM patients has changed over the first year of the pandemic. Patients and methods The Spanish MM Collaborative Group (Pethema-GEM) conducted a survey at national level on plasma cell disorder patients infected by SARS-Cov-2 between March 2020 and February 2021. Sixty-six (69%) out of 96 contacted healthcare centers, from all 17 regions in Spain, reported 502 patients. Data on Covid-19 acute and post-acute phase outcomes (hospitalization, oxygen requirements, severity of symptoms and mortality) were reported first in May 2020 (Martinez-Lopez et al, BCJ 2021) and updated in February 2021. In this study, we compared outcome occurrence between two study periods: P1, a period of extreme stress for the healthcare system in Spain, from March to mid-June 2020; and a second period, P2, up to mid-February 2021 with a sustained but lower burden on the national health care system. Results Among the 451 patients with plasma cell disorders and a Sars-Cov-2 infection documented with an rRT-PCR positive test, 377 (84%) were MM patients, 15 SMM (3%), 40 MGUS (9%) and 19 amyloidosis (4%). The number of MM weekly reported cases was 57% (95%CI, 48-65) lower in P2 (188 cases in 35 weeks) compared to P1 (189 cases in 15 weeks), p & lt;0.001. The mean (SD) age and the proportion of men did not differ between P1 and P2, respectively 69.8 (10.9) vs 68.6 (11.0) years, p=0.6, and 53.3% vs 59.6%, p=0.2. MM patients with active or progressive disease at time of Covid-19 diagnosis were 24% in P1 and 34% in P2, p=0.05; patients on active treatment were more frequent in P1, 89%, than in P2, 79%, p=0.01. MM treatment was withheld in 78% and 82% of patients, p=0.4. Covid-19 treatment changed over time: MM inpatients received more remdesivir and corticoids in the second period (3% vs 31% p & lt;0.001, and 49% vs 73%, p & lt;0.001, respectively). In P1, 90% of the reported MM patients were hospitalized compared to 71% in P2, p & lt;0.001. Thirty-one and 41% of patients did not require oxygen support during P1 and P2, respectively; non-invasive ventilation in 19% and 14%, and mechanical ventilation in 7% and 8%, p=0.12. Overall, acute clinical Covid-19 severity was reduced from P1 to P2: 75% to 51%, p & lt;0.001: moderate/severe pneumonia was reduced from 68% to 36%, p & lt;0.001 but severe distress syndrome increased from 7% to 15%, p=0.03. However, mortality in all reported patients was 30.7% in P1 vs 26.1% in P2, p=0.3; and no differences in mortality were observed in hospitalized patients, 32.2% in P1 and 35.3% in P2, p=0.6. We performed a multivariable adjustment with the predictors identified in our previous study (BCJ 2021) and confirmed that inpatient mortality was similar in both study periods, odds ratio (OR) 0.99 (95%CI 0.59-1.66). Independently of the study period, an increased mortality was observed in men (OR 1.81, 1.08-3.05), patients over 65 (OR 2.40, 1.33-4.36), and patients with active or progressive disease (OR 2.12, 1.24-3.62). The severity of Covid-19 clinical outcomes -besides mortality, was associated with increased age but not with active or progressive disease. Conclusions Although COVID-19 clinical severity has decreased over the first year of the pandemic in multiple myeloma patients, mortality remains high with no change between the initial weeks of the pandemic and the following months. Prevention and vaccination strategies should be strengthened in this vulnerable population, particularly in patients with active or progressive disease at time of Covid-19 diagnosis. Disclosures Martínez-López: Janssen, BMS, Novartis, Incyte, Roche, GSK, Pfizer: Consultancy; Roche, Novartis, Incyte, Astellas, BMS: Research Funding. Mateos: Oncopeptides: Honoraria, Membership on an entity's Board of Directors or advisory committees; Regeneron: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees; Adaptive Biotechnologies: Honoraria, Membership on an entity's Board of Directors or advisory committees; Sea-Gen: Honoraria, Membership on an entity's Board of Directors or advisory committees; AbbVie: Honoraria; Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene - Bristol Myers Squibb: 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; Bluebird bio: Honoraria; GSK: Honoraria; Oncopeptides: Honoraria. López-Muñoz: Amgen: Consultancy. Sureda: GSK: Consultancy, Honoraria, Speakers Bureau; Sanofi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Roche: Other: Support for attending meetings and/or travel; Mundipharma: Consultancy; Bluebird: Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Kite, a Gilead Company: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; MSD: Consultancy, Honoraria, Speakers Bureau; BMS/Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Support for attending meetings and/or travel, Speakers Bureau; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Support for attending meetings and/or travel, Research Funding, Speakers Bureau. Rosinol: Janssen, Celgene, Amgen and Takeda: Honoraria. Lahuerta: Celgene, Takeda, Amgen, Janssen and Sanofi: Consultancy; Celgene: Other: Travel accomodations and expenses. San-Miguel: AbbVie, Amgen, Bristol-Myers Squibb, Celgene, GlaxoSmithKline, Janssen, Karyopharm, Merck Sharpe & Dohme, Novartis, Regeneron, Roche, Sanofi, SecuraBio, Takeda: Consultancy, Other: Advisory board.

Abstract: Introduction: Carfilzomib dosed at 56 mg/m2 twice a week in combination with dexamethasone (Kd) is a standard of care for RRMM after 1-3 prior lines (PL) based on the ENDEAVOR study. Later, the ARROW study showed Kd dosed at 70 mg/m2 weekly to be superior to Kd dosed at 27 mg/m2 twice a week on RRMM patients (pts) after 2-3 PL. On the other side, Cyclophosphamide is an alkylating agent that has been widely combined with proteasome inhibitors and immunomodulatory drugs in MM, improving their efficacy with a good safety profile. In this phase 2 randomized study, we have compared Kd plus cyclophosphamide (KCyd) with Kd in RRMM after 1-3PL, both with K dosed weekly at 70 mg/m2. Patients and methods: RRMM after 1-3 PL of therapy were included in the trial. Consistently with the ENDEAVOR population, previous therapy with proteasome inhibitors was allowed but refractory patients were excluded. Pts were randomized 1:1 to receive K at a dose of 70 mg/m2 iv on days 1, 8 and 15 plus dexamethasone at a dose of 20 mg PO the day on and the day after K plus/minus KCyd at a dose of 300 mg/m2 IV on days 1, 8 and 15 of each 28 days-cycle, as continuous treatment until progressive disease or unacceptable toxicity. The primary endpoint was PFS and key secondary endpoints included response rates, safety profile, and OS. Results: Between January 2018 and February 2020, 198 RRMM pts were included. 97 pts were randomized to KCyd and 101 to Kd. The baseline characteristics of the patients were well balanced between both groups. The median age was 70 years, and 70% and 28% of pts were older than 65 and 75. The median number of PL was one; 61% of pts had received 1 prior line. 94% and 92% of patients had been exposed to bortezomib in the KCyd and Kd and all of them were sensitive. 72% and 67% of patients had been exposed to IMiD's and 51% and 55% of them were IMiD's-refractory in the KCyd and Kd. Only 4 and 6 patients in KCyd and Kd, had received anti-CD38 antibodies being all refractory. After a median f/u of 15.6 months, median PFS was 20.7 m and 15.2 m in KCyd and Kd (p=0.2). In pts after 1PL, median PFS has not been reached in any arm (p=0.4) and in patients after 2-3PL, KCyd resulted in a median PFS of 20.7 vs 11m for Kd (p=0.4). Of note, in the IMiD-refractory population, the addition of Cy to Kd resulted in a significant benefit in terms of PFS: 26.2 months vs 7.7 months in the Kd arm (p=0.01). OS is immature with 23 and 25 events so far in KCyd and Kd, respectively. The ORR was 78% for KCyd and 73% for Kd: 20% of patients in both arms achieved at least complete response, 33% and 28% very good partial response, respectively, and 25% partial response in both arms. The MRD-ve rate was 4% and 5%. As far as toxicity is concerned, neutropenia was the only hematological adverse event more frequently reported in KCyd compared with Kd, of any grade (24% vs 11%) and grade 3-4 (13% vs 7%). This did not translate into more infections and the rate was comparable in both arms (5% G3-4 in both arms). Thrombocytopenia of any grade and grade 3-4 occurred in 14%/1% and 18%/10% in KCyd/Kd. Cardiovascular events of any grade occurred in 22% and 30% of patients in KCyd and Kd. Nine pts in KCyd developed G3-4 cardiovascular events, these included atrial fibrillation (1pt), cardiac failure (2 pts), myocardial infarct (2 pts), and hypertension (4 pts). In the Kd arm, 11 patients developed G3-4 cardiovascular events and consisted of hypertension in most of them (9 pts). Conclusion: Cyclophosphamide added to Kd 70 mg/m2 weekly in RRMM pts after 1-3 PL prolonged the PFS as compared to Kd particularly in the lenalidomide-refractory population. The administration of K at a dose of 70 mg/m2 weekly was safe and more convenient and overall, the toxicity profile was manageable in both arms. Disclosures Mateos: Abbvie/Genentech: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Regeneron: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen-Cilag: Consultancy, Honoraria; PharmaMar-Zeltia: Consultancy; Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Honoraria, Membership on an entity's Board of Directors or advisory committees; GlaxoSmithKline: Consultancy; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Honoraria, 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; Adaptive Biotechnologies: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Ocio:Janssen: Consultancy, Honoraria, Speakers Bureau; Celgene: Consultancy, Honoraria; Asofarma: Honoraria; Sanofi: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Takeda: Honoraria; GSK: Consultancy; MDS: Honoraria; Secura-Bio: Consultancy; Oncopeptides: Consultancy. Sureda Balari:Novartis: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Roche: Honoraria; Takeda: Consultancy, Honoraria, Speakers Bureau; Sanofi: Consultancy, Honoraria; Merck Sharpe and Dohme: Consultancy, Honoraria, Speakers Bureau; Celgene/Bristol-Myers Squibb: Consultancy, Honoraria; BMS: Speakers Bureau; Incyte: Consultancy; Celgene: Consultancy, Honoraria; Gilead/Kite: Consultancy, Honoraria. Oriol:Celgene/Bristol-Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Amgen: Consultancy, Speakers Bureau; Janssen: Consultancy; Sanofi: Consultancy, Membership on an entity's Board of Directors or advisory committees; GlaxoSmithKline: Membership on an entity's Board of Directors or advisory committees. Rosinol Dachs:Janssen: Honoraria; Celgene: Honoraria; Amgen: Honoraria; Takeda: Honoraria; Sanofi: Honoraria. Blade Creixenti:Takeda: Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees. San-Miguel:Amgen, BMS, Celgene, Janssen, MSD, Novartis, Takeda, Sanofi, Roche, Abbvie, GlaxoSmithKline and Karyopharm: Consultancy, Membership on an entity's Board of Directors or advisory committees.

Abstract: Glycosylation is recognized as a key process for proper megakaryopoiesis and platelet formation. The enzyme uridine diphosphate (UDP)-galactose-4-epimerase, encoded by GALE, is involved in galactose metabolism and protein glycosylation. Here, we studied 3 patients from 2 unrelated families who showed lifelong severe thrombocytopenia, bleeding diathesis, mental retardation, mitral valve prolapse, and jaundice. Whole-exome sequencing revealed 4 variants that affect GALE, 3 of those previously unreported (Pedigree A, p.Lys78ValfsX32 and p.Thr150Met; Pedigree B, p.Val128Met; and p.Leu223Pro). Platelet phenotype analysis showed giant and/or grey platelets, impaired platelet aggregation, and severely reduced alpha and dense granule secretion. Enzymatic activity of the UDP-galactose-4-epimerase enzyme was severely decreased in all patients. Immunoblotting of platelet lysates revealed reduced GALE protein levels, a significant decrease in N-acetyl-lactosamine (LacNAc), showing a hypoglycosylation pattern, reduced surface expression of gylcoprotein Ibα-IX-V (GPIbα-IX-V) complex and mature β1 integrin, and increased apoptosis. In vitro studies performed with patients-derived megakaryocytes showed normal ploidy and maturation but decreased proplatelet formation because of the impaired glycosylation of the GPIbα and β1 integrin, and reduced externalization to megakaryocyte and platelet membranes. Altered distribution of filamin A and actin and delocalization of the von Willebrand factor were also shown. Overall, this study expands our knowledge of GALE-related thrombocytopenia and emphasizes the critical role of GALE in the physiological glycosylation of key proteins involved in platelet production and function.

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 Inherited thrombocytopenias (ITs) are a heterogeneous group of rare platelet disorders. which lead not only to increased bleeding, but also to syndromic forms. ITs are caused by genetic alterations in megakaryopoiesis-related genes. In the last years, whole-exome sequencing (WES) has allowed the identification of novel genes involved in IT. Aim To perform the molecular, clinical and platelet characterization of two unrelated families with syndromic IT, to unveil the underlaying alteration leading to the disease. To explore the functional role of the identified alterations during megakaryocytic (Mk) differentiation. Methods WES was performed in two unrelated non-consanguineous families with lifelong severe macrothrombocytopenia (MCT), bleeding, and extra-hematological manifestations. Bleeding score (BS) was recorded by ISTH-BAT. Platelet phenotyping included platelet count (P), blood film, aggregometry (LTA) and flow cytometry (FC). UDP-galactose-4-epimerase enzymatic activity was measure by HPLC/MS/MS. In vitro functional studies were performed through overexpression of GALE genetic variants in human K562 cell line to elucidate its role in Mk differentiation, by measuring cell ploidy and expression of CD41, CD61 and CD42b surface markers after 7-days of PMA treatment. Results Family pedigrees are shown in Figure 1. Three patients (A.II.1, A.II.2 and B.II.1) were referred due to lifelong severe MCT and moderate-severe bleeding tendency (Figure 1). Moreover, they presented mental retardation, mitral insufficiency, and increased bilirubin levels. Blood film revealed enlarged, giant, and grey platelets (A.II.1: 36%, 6% and 54%, respectively; A.II.2: 56%, 4%, 34%, respectively; B.II.1: 32%, 46%, 12%). LTA showed moderate/severe impaired aggregation with ADP, TRAP-6, CRP, epinephrine, arachidonic acid, and ristocetin. FC confirmed null secretion of alpha and dense granules in A.II.1, A.II.2 and reduced levels in B.II.1 (7.8%, 8.1%, 28.3% respectively, vs. 51.7% control platelets with ADP 10µM; 10.8%, 7.8%, 36.7% respectively, vs. 95.6% control platelets with TRAP6 25µM). WES revealed that both pedigrees carried compound heterozygous variants in GALE (NM_001127621.2): c.230_231insTGTT; p.Lys78Valfs*32 (exon 3), and c.449C & gt;T; p.Thr150Met (exon 5) in A.II.1 and A.II.2 patients; and, c.668T & gt;C, p.Leu223Pro (exon 7), and c.382G & gt;A, p.Val128Met (exon 5) in B.II.1 (Figure 1). Enzymatic activity of the GALE-encoded protein UDP-galactose-4-epimerase was severely reduced in the affected patients: both A.II.1, A.II.2 patients had 1.3 μmol/h/g hemoglobin (control: 8.8 μmol/h/g hemoglobin), and B.II.1 patient had 0.6 μmol/h/g hemoglobin (control: 8 μmol/h/g hemoglobin). Furthermore, in vitro overexpression assays between wild-type GALE and p.Thr150Met, p.Leu223Pro and p.Val128Met variants, confirmed a delayed maturation of Mks upon PMA treatment (at 3, 5 and 7 days). characterized by a significant reduction in the expression of the megakaryocytic surface markers CD41, CD61 and CD42b. Conclusion WES has allowed us to identify pathogenic variants in GALE, which were associated with syndromic IT characterized by severe macrothrombocytopenia. Patients harboring these pathogenic variants presented moderate to severe bleeding tendency associated with cardiovascular and neurological abnormalities. Regarding the platelet phenotype, the presence of giant and grey platelets and the absence of both platelet granules were the most remarkable features reported. Moreover, these GALE variants led to an alteration in in vitro Mk maturation, supporting the thrombocytopenic phenotype observed in patients. Funding ISCIII (PI17/01966, PI 17/01311, PI20/00926), GRS (GRS2061A/19, GRS2135/A/2020), Fundación Séneca (19873/GERM/15), Fundación Mutua Madrileña (AP172142019), Premio López Borrasca (2019), Grupo Trabajo Patología Hemorrágica-SETH (2020). Figure 1 Figure 1. Disclosures Hernández-Rivas: Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene/BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees.

Abstract: Introduction : In patients (pts) with multiple myeloma (MM), next generation flow cytometry (NGF) and next generation sequencing have shown an increased capacity to identify the presence of disease and to anticipate patient's prognosis as compared to serum protein immunofixation (IFE). However, both methods rely on bone marrow (BM) samples and it is important to explore alternative techniques applicable in more accessible samples such as peripheral blood. Patients and Methods: Newly diagnosed MM pts enrolled in the PETHEMA/GEM2012MENOS65 trial received six cycles of induction with bortezomib, lenalidomide and dexamethasone (VRD), intensification with high-dose therapy (melphalan or busulfan and melphalan) followed by autologous stem cell transplantation and consolidation with two more cycles of VRD. At the end of the treatment (post-consolidation), the M-protein (MP) was analyzed in serum by conventional IFE and by EXENT Quantitative Immunoprecipitation Mass Spectrometry using IgG/A/M, κ, λ, free κ and free λ isotypic beads; negative samples by EXENT were re-analyzed by liquid chromatography mass spectrometry (LC-MS). The presence of clonal plasma cells in BM samples was investigated by NGF following the Euroflow guidelines (sensitivity≥10 -5). Samples from the first 164 pts enrolled in the trial were analyzed in this study. Results : After consolidation, persistent disease was detected in 42 (26%) pts by IFE, in 56 (34%) by EXENT and in 72 (44%) by NGF. Surprisingly, the presence or absence of disease by IFE did not discriminate pts with different progression-free survival (PFS), but both EXENT and NGF segregated two cohorts with a significantly different PFS (p=0.0016 and p & lt;0.0001, respectively; fig1A and 1C). Importantly, we observed that among pts in complete response (IFE negative), EXENT and NGF also distinguished two groups with different PFS (p=0.002 and p=0.0001, respectively.) Analyzing the results obtained with EXENT and NGF, we found that 76% were concordant (44 EXENT +/NGF +, 80 EXENT -/NGF -) and 24% discordant (28 EXENT -/NGF + and 12 EXENT +/NGF -). When we compared pts´ PFS according the combined results of both methods (fig 1D), we learnt that the 3 comparisons reaching statistical significance were EXENT +/NGF + vs EXENT -/NGF - (p & lt;0.0001), EXENT +/NGF + vs EXENT +/NGF - (p=0.0394) and EXENT -/NGF - vs EXENT -/NGF + (p=0.0363). Considering NGF as a reference, the negative predictive value (NPV) of EXENT was 74% overall (96% in MRD levels ≥10 -4, p & lt;0.0001; 89% in & lt;10 -4 - ≥10 -5 p & lt;0.0001; and 84% in ≥10 -6 cases, p=0.0524). Samples deemed negative by EXENT were re-analyzed with LC-MS. In 63 of them (58%) the MP was identified using LC-MS and therefore a total of 119 samples (73%) were considered positive with EXENT & LC-MS. We first confirmed that EXENT & LC-MS segregated two cohorts with different PFS (fig 1B, p=0.0193) Then, as earlier, we analyzed the results obtained with EXENT & LC-MS and NGF, finding that 65% were concordant (67 EXENT & LC-MS +/NGF +, 40 EXENT & LC-MS -/NGF -) and 35% discordant (5 EXENT & LC-MS -/NGF + and 52 EXENT & LC +/NGF -). Again, we compared pts´ PFS according the combined results of both methods (fig 1E) learning now that only the comparisons EXENT & LC-MS +/NGF + vs EXENT & LC-MS -/NGF - (p=0.0006) and EXENT & LC-MS +/NGF + vsEXENT & LC-MS +/NGF - (p=0.0006) reached statistical significance. With these results, the NPV of EXENT & LC-MS was 89% overall (100% in MRD levels ≥10 -4 p & lt;0.0001; 100% in & lt;10 -4 - ≥10 -5 p & lt;0.0001; and 89% in ≥10 -6 cases p=0.0914). Finally, we observed that whereas among pts deemed EXENT +, NGF identified 2 cohorts with different PFS (a NGF -group of 12 pts displaying a longer PFS as compared with those NGF +; median PFS: 4 years vs not reached, p=0.039) among EXENT & LC-MS - cases (n=45) NGF was not able to show any added clinical value. Conclusions : The use of IFE post-consolidation in pts with MM, as opposed to EXENT and NGF, did not identify pts with different PFS. When referred to NGF, EXENT provided a similar clinical value and displayed a very high NPV, increased further with the addition of LC-MS; this could be utilised to avoid the performance of a BM aspiration after treatment in pts with undetectable disease. Regarding EXENT + and/or LC-MS + cases future quantitative and sequential studies could reveal whether are due to the long half-lives of the MP or represent quiescent low-level disease. Figure 1 Figure 1. Disclosures Puig: Amgen, Celgene, Janssen, Takeda and The Binding Site: Honoraria; Amgen, Celgene, Janssen, Takeda: Consultancy; Celgene: Speakers Bureau; Celgene, Janssen, Amgen, Takeda: Research Funding. Paiva: Bristol-Myers Squibb-Celgene, Janssen, and Sanofi: Consultancy; Adaptive, Amgen, Bristol-Myers Squibb-Celgene, Janssen, Kite Pharma, Sanofi and Takeda: Honoraria; Celgene, EngMab, Roche, Sanofi, Takeda: Research Funding. Cedena: Janssen, Celgene and Abbvie: Honoraria. Rosinol: Janssen, Celgene, Amgen and Takeda: Honoraria. Martínez-López: Roche, Novartis, Incyte, Astellas, BMS: Research Funding; Janssen, BMS, Novartis, Incyte, Roche, GSK, Pfizer: Consultancy. Oriol: Karyopharm: Consultancy, Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Consultancy, Membership on an entity's Board of Directors or advisory committees; Sanofi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; GSK: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; BMS/Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Sureda: Bluebird: Membership on an entity's Board of Directors or advisory committees; Kite, a Gilead Company: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Support for attending meetings and/or travel, Research Funding, Speakers Bureau; GSK: Consultancy, Honoraria, Speakers Bureau; Roche: Other: Support for attending meetings and/or travel; BMS/Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Support for attending meetings and/or travel, Speakers Bureau; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Mundipharma: Consultancy; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; MSD: Consultancy, Honoraria, Speakers Bureau; Sanofi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Moraleda: Jazz Pharmaceuticals: Consultancy, Honoraria, Other: Educational Grants, Research Funding; Gilead: Consultancy, Honoraria, Other: Educational Grants, Research Funding; Novartis: Consultancy, Honoraria, Other: Educational Grants, Research Funding; Sandoz: Consultancy, Honoraria; Takeda: Consultancy, Honoraria, Other: Educational Grants, Research Funding; ROCHE: Consultancy, Honoraria, Other: Educational Grants, Research Funding; MSD: Other: Educational Grants, Research Funding; Sanofi: Other: Educational Grants, Research Funding; Pfizer: Other: Educational Grants, Research Funding; NovoNordisk: Other: Educational Grants, Research Funding; Janssen: Other: Educational Grants, Research Funding; Celgene: Other: Educational Grants, Research Funding; Amgen: Other: Educational Grants, Research Funding. Bladé Creixenti: Janssen, Celgene, Takeda, Amgen and Oncopeptides: Honoraria. San-Miguel: AbbVie, Amgen, Bristol-Myers Squibb, Celgene, GlaxoSmithKline, Janssen, Karyopharm, Merck Sharpe & Dohme, Novartis, Regeneron, Roche, Sanofi, SecuraBio, and Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees. Mateos: Regeneron: Honoraria, Membership on an entity's Board of Directors or advisory committees; AbbVie: Honoraria; Adaptive Biotechnologies: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Honoraria, Membership on an entity's Board of Directors or advisory committees; Sea-Gen: 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; Celgene - Bristol Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bluebird bio: Honoraria; GSK: Honoraria; Oncopeptides: Honoraria.

Abstract: Background: Chromosome 14q32 rearrangements involving the immunoglobulin heavy chain gene (IGH) affect less than 5% of chronic lymphocytic leukemia (CLL) patients. Their clinical course is aggressive and the outcome, worse than other CLL subtypes (Cavazzini et al, 2008; Gerrie et al, 2012). However, the biology of CLL showing IGH rearrangements (CLL-IGHR) is not completely defined. The identification of novel recurrent mutations in CLL by next generation-sequencing (NGS) has offered a more comprehensive view into the genomic landscape of the disease and improved the prognostication of CLL. Thus, mutational analysis might be especially useful in those patients with uncertain prognosis, such as those carrying IGH rearrangements. Aim: To analyze the mutational profile of CLL-IGHR patients by targeted NGS in order to improve our understanding of the genetic underpinnings of this subgroup. Methods: The study was based on 899 CLL patients, well characterized at cytogenetic, biological and clinical level, forty-two of them (4.7%) showing IGH rearrangements. Targeted NGS was performed in 231 CLL samples: 117 with 13q deletion, 27 with 11q deletion, 26 trisomy 12, 42 showing IGH rearrangements and the remaining 19 without any cytogenetic alteration. CD19+ B cells were isolated and DNA extracted. SureSelectQXT targeted enrichment technology and a custom-designed panel (MiSeq, Illumina), including 54 CLL-related and recurrent mutated genes, was carried out. The panel yielded 100x or greater coverage on 97% of the genomic regions of interest and the mean coverage obtained was 600x. Mutations were detected down to 3% allele frequency. Results: The mutational analysis of CLL-IGHR patients identified a total of 72 mutations in 32 genes. Seventy-one percent of patients (30/42) harbored at least one mutation. The most frequently mutated genes in this cohort were NOTCH1 (28.6%), POT1 (14.3%), TP53 (9.5%), SF3B1 (7%), BRAF (7%), EGR2 (7%), IGLL5 (7%) and MGA (7%), followed by BCL2, HIST1H1E and FBXW7 (4.8%), uncommonly mutated genes in CLL at these frequencies (Table 1). In fact, mutations in NOTCH1, BRAF, EGR2, BCL2, HIST1H1E and FBXW7 were significantly associated with CLL-IGHR patients (p=0.013, p=0.003, p=0.021, p=0.038, p=0.038 and p=0.021 respectively). In terms of time to the first therapy (TFT), CLL-IGHR had an intermediate-negative impact (median TFT=24 months) compared to the presence of cytogenetic alterations associated with good prognosis such as 13q deletions (median TFT 〉 120 months; p 〈 0.0001) (Figure 1A). Furthermore, the presence of mutations in the most frequently mutated genes (NOTCH1, POT1, TP53, SF3B1 or BRAF) within patients with IGH rearrangements had a negative clinical impact in the TFT and allowed us to refine the prognosis of this subgroup. Thus, the median TFT of patients with mutations was 1 month while the median TFT of patients without mutations was 14 months (p=0.014) (Figure 1B). A total of 17 out of 42 CLL-IGHR patients (40.5%) carried the t(14;18). Interestingly, patients with t(14;18) were characterized by: 1) A lower mutation frequency (average of mutations/patient=1.05) than the rest of rearrangements with unknown partners (average=2.16; p=0.039), and 2) The presence of mutations in BCL2 (11%) and HIST1H1E (11%). By contrast, CLL-IGHR without BCL2 rearrangement showed mutations in POT1 (20%), TP53 (16%), SF3B1 (12%) and BRAF (12%). Moreover, t(14;18) was significantly associated with good prognosis markers such as the mutated status of the variable region of the immunoglobulin genes (IGHV-M) (p=0.002). However, there was no significant difference in terms of TFT between patients with t(14;18) and patients with other IGH rearrangements (p=0.27). Conclusions: CLL patients with IGH rearrangements showed: i. A high gene mutation frequency; ii. A distinct mutational profile, with recurrent mutations in POT1, EGR2, BRAF, IGLL5 and MGA genes; iii. An adverse clinical outcome refined by the negative effect of genetic mutations. iv. Patients with t(14;18) presented a lower mutation frequency than the rest of rearrangements, carrying mutations in BCL2 and HIST1H1E, and associated with good-prognosis markers such as IGHV-M. Funding:PI15/01471; CIBERONC CB16/12/00233; FEHH-Janssen(MHS); JCyL(MQÁ) Disclosures Mateos: Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy, Honoraria, 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; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; GSK: 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; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; GSK: Consultancy, Membership on an entity's Board of Directors or advisory committees.

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.