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Although advanced‑stage follicular lymphoma (FL) is considered incurable, survival has improved with the introduction of the anti-CD20 antibodies, rituximab (R) and obinutuzumab (G). However, FL can undergo histological transformation (HT) to a more aggressive disease, and a validated model for predicting HT risk is not yet available.We assessed HT incidence, risk factors and outcomes in the phase III, GALLIUM study evaluating R- or G-chemotherapy in patients with previously untreated, advanced-stage FL (ClinicalTrials.gov NCT01332968). HT rates were assessed by repeat tumour biopsy at disease progression or relapse, at the investigator's discretion.Of 1202 patients enrolled, 315 (26.2%) experienced progressive disease; 46 (14.6%) had a biopsy at first progression, 40 of whom had biopsy-confirmed HT. HT risk factors were male sex (subdistribution hazard ratio [sHR], 2.21; 95% confidence interval [CI], 1.16-4.20), elevated baseline serum lactate dehydrogenase (sHR, 3.97; 95% CI, 2.03-7.76), and elevated baseline serum βHT was a low-frequency event associated with poor survival outcomes in the GALLIUM study. Male sex and elevated baseline levels of serum LDH and B2M were significant risk factors for HT. Further research is required to develop validated prognostic indices for HT risk and guide treatment decisions.

The impact of bridging therapy (BT) on CD19-directed chimeric antigen receptor T-cell (CD19CAR-T) outcomes in large B-cell lymphoma (LBCL) is poorly characterised. Current practice is guided by physician preference rather than established evidence. Identification of effective BT modalities and factors predictive of response could improve CAR-T intention to treat and clinical outcomes. We assessed BT modality and response in 375 adult LBCL patients in relation to outcomes following axicabtagene ciloleucel (Axi-cel) or tisagenlecleucel (Tisa-cel). The majority of patients received BT with chemotherapy (57%) or radiotherapy (17%). We observed that BT was safe for patients, with minimal morbidity/mortality. We showed that complete or partial response to BT conferred a 42% reduction in disease progression and death following CD19CAR-T therapy. Multivariate analysis identified several factors associated with likelihood of response to BT, including response to last line therapy, the absence of bulky disease, and the use of Polatuzumab-containing chemotherapy regimens. Our data suggested that complete/partial response to BT may be more important for Tisa-cel than Axi-cel, as all Tisa-cel patients with less than partial response to BT experienced frank relapse within 12 months of CD19CAR-T infusion. In summary, BT in LBCL should be carefully planned towards optimal response and disease debulking, to improve CD19CAR-T patient outcomes. Polatuzumab-containing regimens should be strongly considered for all suitable patients, and failure to achieve complete/partial response to BT pre-Tisa-cel may prompt consideration of further lines of BT where possible.

Patients with chronic lymphocytic leukemia (CLL) progressing on ibrutinib constitute an unmet clinical need. Though BTK and PLCG2 mutations are associated with ibrutinib resistance, their frequency and relevance to progression are not fully understood. In this multicenter retrospective observational study, we analyzed 98 patients with CLL treated with ibrutinib (49 relapsing after an initial response and 49 still responding after ≥1 year of continuous treatment) using a next-generation sequencing (NGS) panel (1% sensitivity) comprising 13 CLL-relevant genes including BTK and PLCG2. BTK hotspot mutations were validated by droplet digital PCR (ddPCR) (0.1% sensitivity). By integrating NGS and ddPCR results, 32/49 relapsing cases (65%) carried at least 1 hotspot BTK mutation and/or PLCG2 mutation(s); in 6/32, BTK mutations were only detected by ddPCR [variant allele frequency (VAF) 0.1-1.2%]. BTK/PLCG2 mutations were also identified in 6/49 responding patients (12%; 5/6 VAF

Thyroid abnormalities are well reported following childhood treatment for Hodgkin Lymphoma (HL). Limited information exists for adult patients and after modern treatments. We analyzed risks of thyroid disorders in 237 female participants treated at the Royal Marsden Hospital 1970-2015. Multivariable analyses of risk according to treatment and time-related factors, survival analyses, and Cox regression modeling were undertaken. Overall, 33.8% of patients reported thyroid disorders (hypothyroidism 30.0% and thyroid nodules 6.8%). Cumulative prevalence was 42.9% by 40 years follow-up. Risks were greatest after supradiaphragmatic radiotherapy (RR = 5.0, p

A significant body of literature has been generated related to the detection of measurable residual disease (MRD) at the time of achieving complete remission (CR) in patients with hairy cell leukemia (HCL). However, due to the indolent nature of the disease as well as reports suggesting long-term survival in patients treated with a single course of a nucleoside analog albeit without evidence of cure, the merits of detection of MRD and attempts to eradicate it have been debated. Studies utilizing novel strategies in the relapse setting have demonstrated the utility of achieving CR with undetectable MRD (uMRD) in prolonging the duration of remission. Several assays including immunohistochemical analysis of bone marrow specimens, multi-parameter flow cytometry and molecular assays to detect the mutant BRAF V600E gene or the consensus primer for the immunoglobulin heavy chain gene (IGH) rearrangement have been utilized with few comparative studies. Here we provide a consensus report on the available data, the potential merits of MRD assessment in the front-line and relapse settings and recommendations on future role of MRD assessment in HCL.

Standard treatment options in classic HCL (cHCL) result in high response rates and near normal life expectancy. However, the disease itself and the recommended standard treatment are associated with profound and prolonged immunosuppression, increasing susceptibility to infections and the risk for a severe course of COVID-19. The Hairy Cell Leukemia Foundation (HCLF) has recently convened experts and discussed different clinical strategies for the management of these patients. The new recommendations adapt the 2017 consensus for the diagnosis and management with cHCL to the current COVID-19 pandemic. They underline the option of active surveillance in patients with low but stable blood counts, consider the use of targeted and non-immunosuppressive agents as first-line treatment for cHCL, and give recommendations on preventive measures against COVID-19.

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

Establishing clonality is an important step towards diagnosing B and T-cell lymphomas. While B-cell clonality is established quickly using flow cytometry, the gold standard for T-cell clonality involves expensive and time-consuming genetic studies. The significance of T-cell clones detected by this method are often more uncertain. More recently, TRBC1 expression on T-cells as detected by flow cytometry has been shown to be a simple, rapid and robust representation of T-cell clonality. This has been implemented in our diagnostic laboratory with clonality reported when TRBC1 expression is identified in15% or85% of T-cells. This study examines the reporting of TRBC1 based clonality using flow cytometry and molecular clonality results in the investigation of T-cell lymphocytosis.All cases tested for T-cell clonality by the molecular laboratory at RMH between 05/04/2021 and 10/11/2021 were identified retrospectively. Molecular and immunophenotyping results were extracted from electronic patient records (EPR). We analyzed TRBC1 status and T-cell receptor (TCR) clonality by molecular rearrangements including TCR beta (TCRB) and TCR gamma (TCRG).284 cases were identified. TRBC1 status as detected by flow cytometry was documented in 82 cases. Our laboratory reported a clonal population by TRBC1 in 27/82 cases. In all 27 cases a clonal T-cell population was also identified in both TCRB and TCRG by molecular testing. In 1 case molecular studies failed due to lack of amplification. No clonal TRBC1 population was described as per laboratory cut-offs in 55 cases. 17/55 were also reported as polyclonal by molecular studies. A weak clonal population of uncertain significance was detected in 4/55 cases. There were clonal populations detected by molecular studies in 31/55 of these cases. In 3/55 cases molecular studies failed.100% of cases with clonal TRBC1 detected by flow cytometry demonstrate T-cell clonality on molecular testing. As per current reporting standards defined in our laboratory, small T cell clones are not reported due to the unknown clinical significance leading to a discrepancy between reports by flow and molecular laboratories. The clinical context and outcomes of these cases is being investigated to understand the clinical significance.

Summary Background Chemoimmunotherapy is typically the standard of care for patients with Waldenstrom macroglobulinemia; however, infectious and hematologic toxic effects are problematic. Acalabrutinib is a selective, potent Bruton tyrosine-kinase inhibitor. The aim of this trial was to evaluate the activity and safety of acalabrutinib in patients with Waldenstrom macroglobulinemia. Methods This single-arm, multicentre, phase 2 trial was done in 19 European academic centres in France, Italy, Greece, the Netherlands, and the UK, and eight academic centres in the USA. Eligible patients were 18 years or older and had treatment naive (declined or not eligible for chemoimmunotherapy) or relapsed or refractory (at least one previous therapy) Waldenstrom macroglobulinemia that required treatment, an Eastern Cooperative Oncology Group performance status of 2 or less, and received no previous Bruton tyrosine-kinase inhibitor therapy. Patients received 100 mg oral acalabrutinib twice per day in 28-day cycles until disease progression or unacceptable toxicity. The primary endpoint was investigator-assessed overall response (at least a minor response) according to the 6th International Workshop for Waldenstrom Macroglobulinemia (IWWM) and the modified 3rd IWWM workshop criteria. The primary outcome and safety were assessed in all patients who received at least one dose of treatment. This study is registered with ClinicalTrials.gov , number NCT02180724 , and is ongoing, but no longer enrolling. Findings Between Sept 8, 2014, and Dec 24, 2015, 122 patients were assessed for eligibility, of which 106 (87%) patients were given acalabrutinib (14 were treatment naive and 92 had relapsed or refractory disease). With a median follow-up of 27·4 months (IQR 26·0–29·7), 13 (93% [95% CI 66–100]) of 14 treatment naive patients achieved an overall response and 86 (93% [86–98]) of 92 relapsed or refractory patients per both the modified 3rd and 6th IWWM criteria. Seven (50%) of 14 treatment naive patients and 23 (25%) of 92 relapsed or refractory patients discontinued treatment on study. Grade 3–4 adverse events occurring in more than 5% of patients were neutropenia (17 [16%] of 106 patients) and pneumonia (7 [7%]). Grade 3–4 atrial fibrillation occurred in one (1%) patient and grade 3–4 bleeding occurred in three (3%) patients. The most common serious adverse events were lower respiratory tract infection (n=7 [7%]), pneumonia (n=7 [7%]), pyrexia (n=4 [4%]), cellulitis (n=3 [3%]), fall (n=3 [3%]), and sepsis (n=3 [3%]). Pneumonia (n=5 [5%]) and lower respiratory tract infection (n=4 [4%]) were considered treatment related. One treatment-related death was reported (intracranial hematoma). Interpretation This study provides evidence that acalabrutinib is active as single-agent therapy with a manageable safety profile in patients with treatment-naive, or relapse or refractory Waldenstrom macroglobulinemia. Further studies are needed to establish its efficacy against current standard treatments and to investigate whether outcomes can be improved with combination therapies. Funding Acerta Pharma.

Chronic lymphocytic leukemia (CLL) is a disease of the elderly, characterized by immunodeficiency. Hence, patients with CLL might be considered more susceptible to severe complications from COVID-19. We undertook this retrospective international multicenter study to characterize the course of COVID-19 in patients with CLL and identify potential predictors of outcome. Of 190 patients with CLL and confirmed COVID-19 diagnosed between 28/03/2020 and 22/05/2020, 151 (79%) presented with severe COVID-19 (need of oxygen and/or intensive care admission). Severe COVID-19 was associated with more advanced age (≥65 years) (odds ratio 3.72 [95% CI 1.79–7.71]). Only 60 patients (39.7%) with severe COVID-19 were receiving or had recent (≤12 months) treatment for CLL at the time of COVID-19 versus 30/39 (76.9%) patients with mild disease. Hospitalization rate for severe COVID-19 was lower (p < 0.05) for patients on ibrutinib versus those on other regimens or off treatment. Of 151 patients with severe disease, 55 (36.4%) succumbed versus only 1/38 (2.6%) with mild disease; age and comorbidities did not impact on mortality. In CLL, (1) COVID-19 severity increases with age; (2) antileukemic treatment (particularly BTK inhibitors) appears to exert a protective effect; (3) age and comorbidities did not impact on mortality, alluding to a relevant role of CLL and immunodeficiency.

Mantle cell lymphoma (MCL), an aggressive B-cell malignancy accounting for 6% of non-Hodgkin lymphomas, remains incurable with standard therapy. Despite the approval of bortezomib,[1][1] temsirolimus,[2][2] lenalidomide,[3][3] ibrutinib[4][4] and acalabrutinib,[5][5] patients with relapsed

Background: In the treatment of advanced Hodgkin lymphoma, it is increasingly common UK practice to modify escalated BEACOPP (eBPP) by removing oral procarbazine and replacing it with intravenous dacarbazine (250mg/m2 D2-3) to reduce haematopoietic stem cell and gonadal toxicity. However, published data of the "escalated BEACOPDac (eBPDac)" regimen are very limited. Methods: This is a retrospective study of 225 patients from 20 centres in the UK, Ireland and France who were treated with eBPDac first line for advanced stage Hodgkin Lymphoma. Toxicity outcomes were compared with 58 matched patients treated with eBPP at 4 UK centres and survival outcomes were compared with 2073 eBPP patients in the HD18 trial 1 and with 1088 patients aged 18-59y in the RATHL trial 2,3. Most eBPDac patients were treated as per HD18 protocol. The 34 patients treated in Paris followed the AHL2011 protocol with two courses of eBPDac given upfront and if iPET2 negative were deescalated to 4 cycles of ABVD. Toxicity outcomes: Toxicity was compared between eBPDac patients (n=225; median follow-up 22.1 months) and matched real-world UK eBPP patients (n=58; median follow-up 52.7 months) over the first 4 cycles. eBPP and eBPDac patients were well matched with no significant differences in age (median 23 y vs 26 y), sex, stage (stage 3/4 82% vs 83%) and international prognostic score (IPS 3+ 74% vs 65%). 55% of eBPDac patients received only 4 cycles (vs 12% of eBPP patients; p Disease outcomes: The eBPDac patients (n=225) were younger than the HD18 patients (median age 26 y vs 35 y, p Figure 1 shows Kaplan-Meier plots for progression-free survival (PFS) and overall survival (OS). The PFS at 22 months (median follow-up) of eBPDac patients was 94.9% (91.7-98.3%) which is similar to HD18 3 year PFS of 92.3% (91.1-93.5%) and appears superior to RATHL 5 year PFS 81.4% (78.9-83.7%). The difference in PFS between eBPDac and RATHL is most marked in IPS3+ patients. The OS rates with all 3 regimens are excellent, with 22 month eBPDac OS estimate of 98.9% (97.4-100%). Summary/Conclusion: Accepting the limitations of a retrospective study, we suggest that substituting dacarbazine for procarbazine is unlikely to compromise the efficacy of eBPP and may have some toxicity benefits. Despite the clear preference of clinicians to offer this regimen to high-risk advanced stage patients, with nearly 2 years median follow-up we have observed similar PFS and OS compared to HD18 but superior survival estimates compared with 18-59y RATHL patients, suggesting that eBPDac is highly efficacious for the treatment of Hodgkin lymphoma. References: 1Borchmann P et al. Lancet 2017; 390:2790-2802 2Johnson P et al. NEJM. 2016; 374:2419-2429 3Russell J et al. Ann Hematol 2021; 100:1049-1058 Figure 1 Figure 1. Disclosures Brice: MSD: Research Funding; Amgen: Other: Travel/accommodations/expenses; Roche: Other: Travel/accommodations/expenses; Takeda: Research Funding. Menne: Kite/Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel grant, Research Funding, Speakers Bureau; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel grants; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel grants; Astra Zeneca: Research Funding; Jazz: Other: Travel grants; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel grants; Bayer: Other: Travel grants; Kyowa Kirin: Other: Travel grants; Daiichi Sankyo: Honoraria, Membership on an entity's Board of Directors or advisory committees; Atara: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Other: Honoraria for Lectures; Roche: Other: Honoraria for Lectures. Osborne: Roche: Other; Takeda: Other; Pfizer: Other; Servier: Other; Gilead: Other; Novartis: Other; MSD: Other. Ardeshna: Gilead, Beigene, Celegene, Novartis and Roche: Membership on an entity's Board of Directors or advisory committees; Gilead, Beigene, Celegene, Novartis and Roche: Honoraria; Norvartis, BMS, Autolus, ADCT, Pharmocyclics and Jansen: Research Funding. Collins: Pfizer: Honoraria; Amgen: Research Funding; AstraZeneca: Honoraria, Research Funding; Beigene: Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria, Speakers Bureau; Celgene: Research Funding; ADC Therapeutics: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celleron: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Merck Sharp & Dohme: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel expenses, Speakers Bureau. Cwynarski: Adienne, Takeda, Roche, Autolus, KITE, Gilead, Celgene, Atara, Janssenen: Other. Davies: Janssen: Honoraria, Research Funding; Karyopharm Therapeutics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Acerta Pharma/AstraZeneca: Honoraria, Research Funding; ADC Therapeutics: Honoraria, Research Funding; BioInvent: Research Funding; Incyte: Membership on an entity's Board of Directors or advisory committees; Kite: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel to scientific conferences, Research Funding; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel to scientific conferences, Research Funding. Furtado: Abbvie: Other: Conference support. Gallop-Evans: Takeda: Membership on an entity's Board of Directors or advisory committees; Kyowa-Kirin: Membership on an entity's Board of Directors or advisory committees. Iyengar: Gilead: Membership on an entity's Board of Directors or advisory committees, Other: conference support, Speakers Bureau; Takeda: Membership on an entity's Board of Directors or advisory committees, Other: conference support, Speakers Bureau; Beigene: Membership on an entity's Board of Directors or advisory committees; Abbvie: Other: conference support; Janssen: Other: conference support, Speakers Bureau. Linton: Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Aptitude Health: Honoraria; Hartley Taylor: Honoraria; University of Manchester: Current Employment; Celgene: Research Funding; BeiGene: Research Funding; Genmab: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Martinez-Calle: Abbvie: Other. McKay: Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees; Gilead: Honoraria, Other: Travel Support; KITE: 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, Other: Travel Support; Janssen: Honoraria, Other: Travel Support; Beigene: Honoraria, Membership on an entity's Board of Directors or advisory committees; BMS/Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees. Nagumantry: Takeda, Alexion, Abbvie: Other. Shah: Abbvie, Janssen and Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees. Uttenthal: Jazz: Other; Takeda: Other; Roche: Other. McMillan: Pfizer: Research Funding; F. Hoffmann-La Roche Ltd: Consultancy, Honoraria, Speakers Bureau; Amgen: Membership on an entity's Board of Directors or advisory committees; Abvie: Membership on an entity's Board of Directors or advisory committees. Follows: Janssen, Abvie, Roche, AZ: Other.

Introduction Breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) is a T-cell lymphoma associated with textured breast implants, recently recognized by the revised WHO Classification. Recommended management for BIA-ALCL involves a multidisciplinary team (MDT) approach with breast surgery, haemato-oncology, pathology, radiology and oncoplastic input. Definitive management for the 'effusion-only' subset is surgical implant and capsule removal; systemic therapy is reserved for 'mass-forming' and 'advanced-disease' cohorts. Overall prognosis is excellent with the vast majority achieving remission. Although the diagnostic and treatment paradigm is established, post treatment surveillance and follow-up guidance varies widely (globally); over-utilisation of imaging tests compromises the patient pathway, impacts limited health-care resources and is associated financial burdens on patients and providers. Recently, newly published consensus guidelines (UK MHRA and USA NCCN clarify follow-up and surveillance imaging (Table 1). The aim of this study was to review our BIA-ALCL specialist centre institutional practise; to quantify the direct economic cost (EC) of imaging surveillance and indirect EC of outpatient clinic (OPC) assessment compared EC if recent guidelines were followed. The secondary aim is to highlight and raise awareness of the latest international guidance to promote the standardisation of practise. Methods A retrospective analysis of a prospectively maintained patient database between July 2015 to October 2019 was conducted, with Institutional Review Board Approval. Data collection included patient demographics, tumour subset, treatment, clinical and imaging surveillance. Follow-up and imaging undertaken for symptomatic concerns / non-BIA-ALCL related pathology was excluded. Imaging costs were calculated using UK NHS tariffs. Results Eleven patients were treated for BIA-ALCL during the study period, with a median age of 49 at diagnosis (range 30-82years). Patients were diagnosed with: effusion-only (n=7), effusion and mass (n=2), mass-only (n=2) subtypes, at a median time of eleven years from implant insertion (IQR 8-12). All patients underwent explantation and en-bloc capsulectomy, with 1 patient required neo-adjuvant (CHOP, Brentuximab) and 1 adjuvant (CHOP) therapy (CHOP. Surveillance with imaging and OPC detected no disease recurrence to date (overall median follow-up 38 months, IQR 12-47). Post treatment episodes of surveillance imaging or follow-up related to patient symptoms were excluded. 8 patients underwent surveillance imaging at our institute (Table 2). Total cost of imaging was £10,396 ($14,396) with a median cost of £1,953 ($2,705) per patient [IQR £526-2029 ($728-2,810)]. 7 patients had completed at least 24 months follow-up since surgery during the study period (Table 3), with 3 patients having not yet completed their follow-up period of two years. Of those with completed follow-up, the median OPC follow-up per patient was 48 months (IQR 38-52), median number of OPC was 7 (IQR 6-11) and the median cost of clinic review was £982 (IQR 804-1395). The surplus cost per patient compared with recommended follow-up was £118 ($164) [IQR £0-531 ($0-738)]. Conclusions Our data shows the variable BIA-ALCL surveillance practise pattern and the associated additional direct and indirect EC of unnecessary asymptomatic surveillance imaging, with an excessive number of follow-up OPC and period of clinical follow-up after complete remission. With no recurrence detected in our patient cohort to date, this data supports the new UK and updated USA NCCN Guidelines (extrapolated from data in other NHLs, and analogous to principles of the ASH Choosing Wisely Campaign) that routine post-treatment surveillance imaging should not be performed in BIA-ALCL patients. Routine asymptomatic post-treatment surveillance imaging is clinically unnecessary and potentially leads to a 'Cascade Effect' of further tests, with increased radiation exposure, excess costs and impact on limited health-care resources. We also support open-access follow-up for patients in remission, to reduce unnecessary follow up appointments. With UK and USA guidelines now available for BIA-ALCL, we support training and education of health-care professionals, global consensus guidelines and a registry, for this rare however increasingly recognised new entity. Figure 1 Figure 1. Disclosures Iyengar: Takeda: Membership on an entity's Board of Directors or advisory committees, Other: conference support, Speakers Bureau; Gilead: Membership on an entity's Board of Directors or advisory committees, Other: conference support, Speakers Bureau; Beigene: Membership on an entity's Board of Directors or advisory committees; Abbvie: Other: conference support; Janssen: Other: conference support, Speakers Bureau. Nicholson: Pfizer: Consultancy; Kite, a Gilead Company: Other: Conference fees, Speakers Bureau; BMS/Celgene: Consultancy; Novartis: Consultancy, Other: Conference fees. El-Sharkawi: Kyowa Kirin: Other: Ad boards; Beigene: Other: Ad boards; ASTEX: Other: Ad boards; Novartis: Other: Travel Support; Takeda: Honoraria; Roche: Honoraria; Janssen: Honoraria, Other: Ad boards; AstraZeneca: Honoraria, Other: Ad boards; AbbVie: Honoraria, Other: Travel Support, Ad boards. Tasoulis: BMJ: Consultancy, Membership on an entity's Board of Directors or advisory committees. Cunningham: Roche: Research Funding; Clovis Oncology: Research Funding; Celgene: Research Funding; Eli Lilly: Research Funding; Bayer: Research Funding; OVIBIO: Membership on an entity's Board of Directors or advisory committees; 4SC: Research Funding; AstraZeneca: Research Funding; MedImmune: Research Funding.

AVENuE - Avelumab in the frontline treatment of advanced classic Hodgkin lymphoma - a window study Background Response adapted ABVD (doxorubicin, bleomycin, vinblastine, dacarbazine) has become a standard of care in many countries for advanced stage classic Hodgkin Lymphoma (cHL), as investigated in the RATHL study: following 2 cycles of ABVD patients with negative (Deauville 1-3) interim PET (iPET2) proceeded to 4 cycles of AVD; those with positive (Deauville 4-5) iPET2 intensified therapy to escalated bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, procarbazine, prednisolone (escBEACOPP) or BEACOPP every 14 days. Overall this strategy was associated with a 3-year progression free survival (PFS) of 82.6%, and outcomes for patients with positive iPET2 were disappointing with 3y progression-free survival (PFS) of 67.5%. More intensive treatment such as upfront use of escBEACOPP has been reported to produce higher PFS (89% at 5 years), but it is unclear whether overall survival (OS) is improved. More intensive treatment is, however, associated with higher risk of toxicity. Inhibitors of programmed cell death protein 1 (PD-1) or programmed death-ligand 1 (PD-L1) have established efficacy in relapsed / refractory cHL with response rates of 55-87%. In the front line setting PD-1 inhibitors have a reported complete metabolic response (CMR) rate of 18-37%. Response to PD-L1 inhibitors in the frontline setting has not been explored. Serial serum TARC (thymus and activation-regulated chemokine) is reported to be prognostic in the frontline treatment of cHL and may aid response assessment because PET interpretation with checkpoint inhibitors is often complex. In the context of PD-1 inhibition, PD-1 expression by immunohistochemistry (IHC) and 9p24.1 copy gain by fluorescence in situ hybridisation (FISH) are reported to correlate with response. Methods AVENuE is a Phase II single-arm multicentre study with sites in the UK and Australia assessing the safety and efficacy of 2 cycles (4 doses) of the PD-L1 inhibitor avelumab for untreated high-risk stage II-IV cHL prior to the iPET2 response adapted approach described above. Eligible patients must be 16-60 years, ECOG 0-1, and have adequate organ function. Patients with; compressive symptoms from lymphoma, autoimmune disorders or immunosuppressive treatment within 2 months are excluded. The primary endpoint is the centrally reviewed PET CMR rate to avelumab. Secondary endpoints are: the safety and tolerability of sequential avelumab and combination chemotherapy as assessed by CTCAE v 5.0; the iPET2 CMR rate after avelumab and 2 cycles of ABVD; PFS and OS at one year. Using a single stage A'hern design, target recruitment is 47 patients to give 90% power at a 0.05% one sided alpha to exclude an overall response rate (ORR) to 2 cycles of avelumab of < 20%; an ORR of 40% would be considered worthy of further study. Recruitment has continued during the COVID-19 pandemic. 29 patients have been enrolled. Exploratory endpoints include correlating disease response with baseline PD-1 copy number by FISH and PD-1 expression by IHC. Serial serum TARC is being explored as an aid to response assessment and changes in peripheral blood immune cell subset are being investigated as possible biomarkers of response. Trial funder: Pfizer Ltd in alliance with Merck KGaA Pfizer Ltd is providing funding as part of an Alliance between Pfizer and Merck KGaA Clinical trials.gov NCT03617666 EUDRACT No.: 2018-002227-42 Disclosures Hawkes: Roche: Membership on an entity's Board of Directors or advisory committees, Other: Travel and accommodation expenses, Research Funding, Speakers Bureau; Regeneron: Speakers Bureau; Merck KgA: Research Funding; Astra Zeneca: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Janssen: Speakers Bureau; Merck Sharpe Dohme: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees; Antigene: Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squib/Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Specialised Therapeutics: Consultancy. Barrington: Bristol Myers Squibb international corporation: Research Funding; Pfizer Inc: Research Funding; Amgen Ltd: Research Funding; Takeda Speakers Bureau: Honoraria. McKay: Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees; Gilead: Honoraria, Other: Travel Support; KITE: 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, Other: Travel Support; Janssen: Honoraria, Other: Travel Support; Beigene: Honoraria, Membership on an entity's Board of Directors or advisory committees; BMS/Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees. Iyengar: Janssen: Other: conference support, Speakers Bureau; Abbvie: Other: conference support; Beigene: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees, Other: conference support, Speakers Bureau; Takeda: Membership on an entity's Board of Directors or advisory committees, Other: conference support, Speakers Bureau. Radford: Takeda: Consultancy, Honoraria, Research Funding, Speakers Bureau; AstraZeneca: Current holder of individual stocks in a privately-held company; ADC Therapeutics: Consultancy, Current holder of individual stocks in a privately-held company, Honoraria, Speakers Bureau; BMS: Honoraria. Shah: Abbvie, Janssen and Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees. Clifton-Hadley: Bristol-Myers Squibb Pharmaceuticals Ltd..: Other: The haematology team at the CTC has received funding (which in part pays staff salary) to Sponsor and coordinate clinical trials.; Amgen: Other: The haematology team at the CTC has received funding (which in part pays staff salary) to Sponsor and coordinate clinical trials.; Celgene: Other: The haematology team at the CTC has received funding (which in part pays staff salary) to Sponsor and coordinate clinical trials.; Merck Sharp and Dohme: Other: The haematology team at the CTC has received funding (which in part pays staff salary) to Sponsor and coordinate clinical trials.; Janssen-Cilag: Other: The haematology team at the CTC has received funding (which in part pays staff salary) to Sponsor and coordinate clinical trials.; Pfizer: Other: The haematology team at the CTC has received funding (which in part pays staff salary) to Sponsor and coordinate clinical trials.; Millennium pharmaceutics inc.: Other: The haematology team at the CTC has received funding (which in part pays staff salary) to Sponsor and coordinate clinical trials.. Collins: Beigene: Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria, Speakers Bureau; Pfizer: Honoraria; Celgene: Research Funding; Amgen: Research Funding; AstraZeneca: Honoraria, Research Funding; ADC Therapeutics: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celleron: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Merck Sharp & Dohme: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel expenses, Speakers Bureau. OffLabel Disclosure: Avelumab prior to frontline chemotherapy in advanced stage classic Hodgkin lymphoma.

Introduction Following completion of chemotherapy with curative intent for DLBCL, for those in remission (CR), numerous national and international guidelines suggest on-going follow-up primarily to detect relapse of disease. For example, the NCCN guidelines suggest that clinical history, examination and blood investigations should be performed every 3-6 months for 5 years and as clinically indicated thereafter. This is essentially a "screening programme" for an at-risk population that continues based on historical routine rather than due to evidence it is of benefit to the patient. Numerous papers have been published suggesting that routine surveillance scans or bloods such as LDH are not useful in this setting. We sought to analyse whether the screening procedures that are performed in the follow-up setting are useful in the detection of relapse in patients followed up in a single centre. Uniquely, we examined each time point separately rather than group all follow-up events together. Methods Data was obtained retrospectively from electronic patient records for all patients in remission following treatment with frontline chemotherapy for DLBCL at the Royal Marsden Hospital between 2005-2016. Screening assessments analysed were symptoms check, clinical examination, LDH >upper limit of normal, lymphocyte: monocyte ratio (LMR) Results Complete data from 262 patients who achieved a CR and were followed up was available. Median age was 63 years (17-94) with 59 patients with stage 1 disease, and 100 with stage 4 disease. The relapse rate was 59/261 (23%), with a median time to relapse of 13 months (2-120). Of the 59, 52 had symptoms they had noted prior to clinic, of whom 28 requested an early appointment to clinic and 22 waited until their routine clinic appointment or sought advice from other health professionals initially. Only 7 patients were picked up only on investigations performed at the hospital, 1 with hypercalcemia and 6 on routine scan with no symptoms, 3 at 3-6months, 2 and 9-12months and 1 at 12-18 months. Of these, 4/7 patients achieved a CR with subsequent therapy. The remaining 202 patients had 2853 clinic appointments, median number per patient 13 (1-44). The negative predictive value of clinical history, examination, LDH, LMR and CT scan was consistently very high (>90%) at all time points. However, the positive predictive value was low for symptoms, 0-35% with the higher values being in the first year. Clinical examination had better PPV due to fewer positive results, including both true and false. LDH and LMR were associated with a poor PPV at all time points. PPV for CT scans was variable (Table 1). Conclusions The "screening" of patients who are in remission from DLBCL requires considerable health resources and cost and also leads to increased exposure of the patient to hospitals which during the COVID-19 pandemic is being discouraged. Likelihood of relapse (which decreases with time) has an impact on the effectiveness of a screening programme, the relapse rate in this cohort was 23% in keeping with other published data. Importantly, the majority of patients had symptoms suggestive of relapse and so the screening was not required. In the few that were asymptomatic when relapse was diagnosed, there was insufficient data to know whether this earlier detection led to a better outcome, however this has not been seen in other published cohorts. Finally the effectiveness of the screening is dependent on the predictive value of the "tests" being used and this dataset shows that whilst the negative predictive value is high, the positive predictive value is very variable and generally poor for all tools used. We propose that educating the patient regarding symptoms of relapse and having patient directed clinical follow-up rather than routine appointments would lead to marked savings in health resources, reduce hospital exposure of patients by eliminating unnecessary visits without compromising the outcome of the patients. Disclosures Cunningham: Lilly: Research Funding; MedImmune: Research Funding; Merck: Research Funding; AstraZeneca: Research Funding; Celgene: Research Funding; Bayer: Research Funding; Janssen: Research Funding; Merrimack: Research Funding; Amgen: Research Funding; 4SC: Research Funding; Clovis Oncology: Research Funding; Sanofi: Research Funding; OVIBIO: Membership on an entity's Board of Directors or advisory committees. Iyengar:Beigene: Consultancy; Janssen: Honoraria; Abbvie: Honoraria; Takeda: Consultancy, Honoraria, Speakers Bureau; Gilead: Consultancy, Honoraria, Speakers Bureau. El-Sharkawi:Abbvie: Consultancy, Honoraria, Speakers Bureau; AstraZeneca: Consultancy, Honoraria, Speakers Bureau; Janssen: Consultancy, Speakers Bureau; Takeda: Honoraria, Speakers Bureau; Innate: Consultancy.

Introduction: Patients with leukemic indolent B-cell Non-Hodgkin Lymphomas (LI B-NHL) that do not easily fall into a distinct pathological category with standard diagnostics can pose a challenge as their optimal management is uncertain. Lack of a clear diagnostic label can deny patients access to novel therapies as regulatory approval of drugs is largely granted within histological categories. Moreover, these patients may be excluded from participation in clinical trials. We report findings from a prospective study evaluating targeted next generation sequencing (NGS) of circulating malignant B-cells in this setting. Methods: Over a period of 4 years, 108 patients with LI B-NHL, deemed unclassifiable on standard peripheral blood (PB) diagnostics, were prospectively enrolled from 14 centres around the UK including ours. Patients with non-clonal lymphocytosis, confirmed CLL-type MBL, CLL (Matutes score 4 or 5), MCL, HCL, high grade lymphoma on standard PB diagnostics were excluded. Clinical and morphological characteristics were analysed. PB immunophenotyping was used for characterisation including ROR1 expression. CD15+ cells were positively selected with magnetic beads for germline DNA. Tumor-germline pairs were analysed with theEuroclonality-NGS DNA capture panel, and ARResT/Interrogate and complementary pipelines, to characterise clonal immunoglobulin rearrangements, translocations and somatic mutations (Stewart et al. ASH annual meeting 2019). Germline variants were subtracted to improve somatic mutation detection. Results: Median age was 72yrs with M:F ratio of 2:1. Incidental lymphocytosis on a routine blood count was the commonest mode of presentation with only a third of patients symptomatic at presentation. Median lymphocyte count was 12.4 x 109/L at the time of sampling. Just under 50% of cases had partial or complete CD5 expression, CD19 and 20 expression was moderate to strong in most cases while ROR1 was negative in most cases. NGS was able to assign a diagnostic category in 11/90 (12%) cases based on detection of IGH;CCND1 (6), IGH;BCL2 (2), IGH;BCL3 (2) translocations and in one case a BRAF mutation with confirmation of hairy cell leukaemia on immuno-morphology. These tests were not triggered by standard diagnostic pathways at initial presentation. Two novel translocations of uncertain significance were detected - RAD51B:BIRC3 and IGHMswitch-MICALL2/INTS1. Clonal IGHV-IGHD-IGHJ rearrangements were detected by NGS and/or Sanger sequencing with predominantly IGHV3 and IGHV4 gene usage, IGHV4-34 being the most common with 15 cases. The majority of rearrangements showed somatic hypermutations above 2% and none could be assigned to the 19 major CLL-associated stereotyped subsets (using ARResT/AssignSubsets). Somatic mutations were detected in 74/108 cases. The most frequently mutated genes were TP53 in 16/108 (15%) and the hotspot MYD88 L265P mutation in 14/108 (13%) with VAF of 20-46%. Other variants detected were distributed among genes associated with NFkB signalling and chromatin remodelling (Figure 1). The MYD88 L265P mutation was present in a fifth of cases with mutations detected (14/74) and was the sole change seen in 7 cases. Accompanying mutations in the remaining cases included CD79B (2), POT1 (1), NFKBIE (1). No concomitant CXCR4 mutations were detected. Median age of the MYD88 L265P cohort was 68 years with male predominance (M:F=10:4). 9/14 presented with an incidental lymphocytosis and median count of 11.18 x 109/L. Lymphadenopathy was present in 3/14 (21%) while 7/14 (50%) had splenomegaly. A paraprotein was detected in 6/14 cases (4 IgM, 1 IgG, 1 IgA). CD5 was expressed in 6/14 cases by flow cytometry. CD19 and 20 were uniformly positive, CD79b was variable and 12/14 cases tested did not express ROR1. Conclusion: This prospective study outlines the value of a targeted NGS panel in enhancing the diagnosis of unclassifiable LI B-NHL thereby improving patient access to novel therapies and clinical trials. It highlights recurrent MYD88 mutations in a subset of patients that have splenomegaly as a frequent feature. 5 year clinical follow up data, currently being gathered in both the MYD88 mutated and overall cohort, will be valuable in further characterisation and risk stratification to inform management of these patients. Disclosures Furtado: Abbvie: Other: Conference Support. El-Sharkawi:Abbvie: Consultancy, Honoraria, Speakers Bureau; AstraZeneca: Consultancy, Honoraria, Speakers Bureau; Janssen: Consultancy, Speakers Bureau; Takeda: Honoraria, Speakers Bureau; Innate: Consultancy. Iyengar:Abbvie: Honoraria; Gilead: Consultancy, Honoraria, Speakers Bureau; Takeda: Consultancy, Honoraria, Speakers Bureau; Janssen: Honoraria; Beigene: Consultancy.

Context Richter syndrome (RS) is the occurrence of an aggressive lymphoma on a background of chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL). It has an incidence of 0.5-1.0%/year with overall prevalence of 2-10% in CLL/SLL. Most cases are of diffuse large B-cell lymphoma subtype (DLBCL-RS) while 5-10% are Hodgkin variant RS (HvRS). Prognosis of patients developing RS is poor with reported overall survival of 1-2 years. In this study, we report the clinical characteristic, treatment and outcome of RS in a single center over a 12-year period. Design All patients with biopsy-confirmed high-grade lymphoma with a background of CLL/SLL between 2004-2015 were identified retrospectively from the histology database of The Royal Marsden Hospital. Information was extracted from Electronic Patient Records (EPR). We analyzed CLL/SLL treatments prior to RS, RS treatment, time from CLL/SLL diagnosis to RS, TP53 disruption status (deletion or mutation), and overall survival (OS). OS was defined as the time from RS to all-cause mortality or last clinic visit. Results 41 patients were identified. The median age at RS diagnosis was 68 years (range 37-85 years) with 3:2 male preponderance. 36 cases (88%) were DLBCL-RS while 5 (12%) were HvRS. Among 30 cases with known CLL TP53 status, 40% had TP53 disruption while 60% did not. 29 patients (71%) had received CLL/SLL treatment while 12 (29%) were treatment-naive. The median time from CLL/SLL diagnosis to RS was 5 years (range 0-26 years). Among DLBCL-RS cases, 75% received R-CHOP/CHOP as first-line treatment, 8% had other regimens, and 17% received supportive care. All HvRS patients received ABVD. The median OS for RS was 16 months (range 0-146). Patients who had received ≥2 CLL/SLL treatment lines had an inferior median OS compared to Conclusion Overall survival in our RS cohort was similar to other published reports. DLBCL-RS, TP53 disruption and ≥ 2 lines of previous CLL/SLL treatment lines were associated with a worse outcome.

7501Background: Bruton tyrosine kinase (BTK) is a clinically validated target in WM. Acalabrutinib is a highly selective, potent, covalent BTK inhibitor that we evaluated in a Phase 2 study of pts ...

Mantle cell lymphoma (MCL) is a clinically heterogeneous, but often aggressive lymphoma characterized by the IGH:CCND1 translocation and cyclin D1 (CCND1) over‐expression. Chromosomal instability, due to disrupted DNA damage response, in conjunction with abnormal activation of cell survival mechanisms underlies the aggressive clinical course in MCL (Jares et al, 2012). In recent years, improved understanding of lymphoma biology has led to the development of a number of small molecule inhibitors. However, the relative rarity of MCL (incidence 0·55 per 100 000) (Smedby & Hjalgrim, 2011) poses a challenge in effectively evaluating these drugs in patients. In vitro studies have been limited by the difficulty of culturing primary MCL cells. Murine models of MCL cell lines are relatively easy to establish in SCID or NOD/SCID/IL2Rγ null (NSG) mice (Wang et al, 2007, 2008a; Weston et al, 2010) but have their limitations. Until a couple of years ago, the only primary mouse model of human MCL described in the literature was established by injection of primary MCL cells into subcutaneous human bone grafts implanted in SCID mice (SCID‐Hu model) (Wang et al, 2008b). Recently, however, disseminated models of human primary MCL have been established in NSG mice (Iyengar et al, 2012; Klanova et al, 2014). We report our experience here in further detail, focussing on the characteristics of MCL engraftment in this model. We used 8‐ to 12‐week‐old NSG mice that were sub‐lethally irradiated (3·75 Gy) 24 h prior to transplantation. Before undertaking xenograft studies with primary cells, we used the MCL cell line JEKO‐1 to assess kinetics, disease burden and distribution of MCL cells in NSG mice. JEKO‐1 cells were transduced with firefly luciferase and injected intravenously into irradiated mice at two doses – 0·5 × 106 and 2 × 106 cells. Bioluminescent imaging was performed at weekly intervals following injection of D‐luciferin. All mice became ill with marked weight loss and had to be sacrificed by day 29. Bioluminescence was observed in the bone marrow and spleen in all mice. Mice injected with the higher cell dose had more rapid disease progression, developed hind leg weakness and had bioluminescence in the central nervous system (CNS) on imaging, indicating involvement (Fig 1). Figure 1 Longitudinal quantitative analysis of bioluminescent imaging (BLI): NSG mice were injected intravenously with the JEKO‐1 cell line transduced with luciferase (Luc) reporter constructs. (A) Representative dorsal view (upper panels) and ventral ... Following this, seven cryopreserved primary MCL samples were identified from the Barts Cancer Institute tissue bank. An additional fresh primary sample derived from a splenectomy was included in the cohort. Ethical approval was obtained from East London and the City Local Research Ethics Committee. Written informed consent was obtained from patients according to the Declaration of Helsinki. All samples had a classical MCL phenotype with CD5/CD20 positivity and were confirmed to have the IGH:CCND1 translocation by fluorescence in situ hybridization (FISH). Irradiated NSG mice were injected intravenously with a dose of 107 unselected MCL cells each. Flow cytometry was performed for mouse CD45 and human CD45, CD3, CD5 and CD20 on peripheral blood samples taken from mice at 3, 6 and 12 weeks. Mice were sacrificed at 20 weeks, or earlier if they met Home Office guidelines, and tissue was harvested for immunohistochemistry (IHC). Cells were flushed from mouse femur for flow cytometry. At 20 weeks, MCL cells were found in the bone marrow and spleen of mice injected with 2 out of the 7 cryopreserved primary samples. Both samples that engrafted had blastoid morphology and one was obtained from a patient with relapsed disease. FISH for IGH:CCND1 on cell suspensions prepared from spleen of NSG mice further confirmed engraftment. None of the mice that engrafted appeared to have bowel involvement as assessed by IHC. Lymphadenopathy was not found at sacrifice. Scattered human CD20‐positive cells were seen in the liver but this was not a consistent feature. Mice remained relatively well until sacrifice (Fig 2A–F). As a next step, secondary transplantation of MCL cells isolated from NSG spleen (107 cells per mouse) was undertaken. Once again, engraftment was seen in mouse spleen and bone marrow on sacrifice at 20 weeks (Fig 2G). Figure 2 Engraftment of human primary mantle cell lymphoma (MCL) in NSG mice: T‐cell depleted human primary mononuclear cells were injected intravenously at a dose of 107 cells per mouse. Peripheral blood was sampled from mice at 3, 6 and 12 weeks, ... In addition to the two cryopreserved samples, evidence of engraftment was also seen in the spleen of NSG mice injected with the fresh primary sample (non‐blastoid). Interestingly, there appeared to be co‐existence of MCL cells and T‐cells in the spleen of mice injected with fresh MCL cells, with tumour cells concentrated around blood vessels. However, these mice had to be sacrificed at 7 weeks due to illness and T‐cell infiltration was found in the liver and bone marrow, without evidence of MCL. We found a similar proliferation of T cells but without evidence of MCL in one of the seven cryopreserved samples that had high T‐cell content (>10%), indicating T‐cell depletion may be important in this scenario. Therefore, similar to the recent report by Klanova et al (2014), we demonstrate human primary MCL engraftment in NSG mice. In contrast to their study where mice were injected with a variable cell dose (1–8 × 107 cells), we injected all mice with a fixed dose of 107 cells. This may explain the lower rate of engraftment in our study. Both cryopreserved samples that engrafted in our study had blastoid morphology, suggesting that a higher cell dose may be required for engraftment of non‐blastoid MCL in this model. In our experiments, mice with primary MCL engraftment were not visibly ill at 20 weeks and disease burden was heaviest in the spleen. In contrast, disease progression was rapid in the JEKO‐1 xenograft, with CNS involvement and hind leg weakness developing by 4 weeks. These findings mirror those of Klanova et al (2014), and are important considerations when designing pre‐clinical experiments involving these models. The longer overall survival of NSG mouse models of primary human MCL could be an advantage for pre‐clinical testing of newer agents, which often require longer periods of administration for efficacy. Finally, our study demonstrates, similar to the findings of Klanova et al (2014), that secondary transplantation can be successfully carried out in this model, highlighting the self‐renewal and tumour‐initiating capacity of primary MCL cells. In summary, this NSG model of human primary MCL is a promising in vivo model for both pre‐clinical drug testing and further understanding MCL biology. Our research provides further insight into the advantages and limitations of this model, which will be crucial for its effective use in pre‐clinical research.

BACKGROUND: T-cell prolymphocytic leukemia (T-PLL) is a rare, aggressive, post thymic lymphoid malignancy, with an incidence of approximately 0.1/100,000 people. T-PLL accounts for ~2% of all mature lymphocytic leukaemias in adults >30 years. Median overall survival (OS) ~20 months and long term remissions are infrequent. Intravenous alemtuzumab, a monoclonal antibody directed against CD52 remains the most effective treatment in T-PLL. At the Royal Marsden Hospital (RMH) we have been using alemtuzumab for T-PLL since the early 1990s. We describe our experience over the last 3 decades. METHODS: We included 174 T-PLL patients that were diagnosed or treated at RMH between 1989-2019. Immunophenotyping data was available through our hematological malignancy diagnostic service (HMDS) from 1998 onwards. Kaplan-Meier analysis was used for OS and disease free interval (DFI) RESULTS: There were 174 patients in total. Mean age at diagnosis was 61 years old (range 32-88) and M: F ratio was ~2:1 (113:61). 90 patients had reliable information on complete blood count (CBC) at diagnosis with median white blood cell count of 74 x 109/L (range 10-918), median hemoglobin 126 g/L (range 59-175) and median platelet count 116 x 109/L (range 7-513). Sufficient immunophenotyping data was available for analysis in 135/174 patients. The results showed predictably high expression of CD2, CD3, CD5, CD7, CD52 and TCRαβ. CD25 was positive in 67/135 (50%) of cases which is higher than the 18-35% seen in the current literature. CD4+/CD8- cases comprised 83/135 (61%) with CD4-/CD8+ 19/135 (14%), CD4+/CD8+ 32/135 (23%) and CD4-/CD8- 2/135 (2%). These results are summarized in table 1. Karyotyping/FISH (fluorescent in-situ hybridization) records showed a clonal result in 84 patients and of these 65/84 (77%) had an aberration of chromosome 14. These comprised 48/65 with inv(14), 6/65 t(14;14), 2/65 t(X;14), 1/65 TCL1 gene rearrangement by FISH and 8/65 with TRA/TRD involvement by FISH. Other frequent abnormalities seen were i(8)(q10) in 31/84 (39%) and complex karyotypic abnormality in 40/84 (48%). Lower frequency abnormalities seen were monosomy 11 in 8/84 (9%), monosomy 12 in 8/84 (9%), trisomy 8 in 6/84 (7%), 17p loss in 5/84 (6%) and mononsomy 13 in 4/84 (5%). Alemtuzumab was used in 116 patients, 69/116 (59%) receiving it as frontline treatment and 47/116 (41%) as salvage therapy. In 50/116 (43%) alemtuzumab was used as single agent, the remaining 66/116 (57%) receiving combination therapy, mostly pentostatin. Mean time from diagnosis to receiving alemtuzumab was 6.8 months (range 0-53 months). Overall response rate (ORR) to alemtuzumab was 94/116 (81%) with complete remission (CR) 69/116 (59%), partial remission (PR) 25/116 (22%) and no response (NR) 20/116 (17%). Alemtuzumab produced better response rates when used as frontline therapy. Table 2 summarizes these results and OS and DFI are shown in figures B and C. Allogeneic stem cell transplant (allo-SCT) was performed in 34 patients. Median OS post allo-SCT was 22 months and median DFI 31 months. Relapse rate post allo-SCT was 47%, non-relapse mortality 38% and transplant related mortality 29%. Figures D and E show OS and DFI post allo-SCT. Although relapse rates are high post allo-SCT there is a small cohort of patients who are achieving long term remission. We analysed OS by decade of diagnosis covering 3 decades 1990-1999, 2000-2009 and 2010-2019. The median OS for the whole cohort was 20.6 months with median OS of 21 months, 23 months and 19 months for each decade respectively. Results are shown in figure A. There was no statistically significant difference between the curves by log-rank analysis. DISCUSSION: Immunophenotyping results were similar to previous published data on T-PLL except for an increase in CD25 expression at 50%. Our data shows that outcomes in T-PLL have remained unchanged since the first decade of alemtuzumab usage, with no improvement in OS in the last 20 years. Despite improvements in diagnostic techniques and supportive care median OS is static at approximately 20 months. These results highlight the need for novel therapies in T-PLL. Given the rarity of T-PLL, international, multi-center, randomised trials are needed to improve outcomes. Disclosures Cross: Royal Marsden Cancer Charity: Other: MD Residency, Research Funding. Iyengar:Abbvie: Honoraria; Janssen: Honoraria. Dearden:Janssen: Honoraria; Genentech: Honoraria; Abbvie: Honoraria; Sanofi: Honoraria.

Introduction Since interim results from the EuroNet-PHL-C1 study1were published in 2013 showing that the gonadotoxic drug procarbazine in COPP can be safely replaced with dacarbazine (COPDac) it is increasingly common practice to modify escalated BEACOPP (eBPP) by removing oral procarbazine and replacing it with intravenous dacarbazine (250mg/m2 D2-3), hoping to reduce haematopoietic stem cell and gonadal toxicity. However, published data of 'escalated BEACOPDac (eBPDac)' regimen are very limited. Methods We collected retrospective data from 15 centres in the UK, Ireland and France, that offer eBPDac therapy for first line advanced stage Hodgkin Lymphoma, and compared outcomes with matched patients treated with eBPP at 4 UK centres. Most patients were treated as per HD15 or HD18 protocol. The 24 patients treated in Paris followed the AHL2011 protocol with two courses of eBPDac given upfront and if iPET2 negative were deescalated to 4 cycles of ABVD. Results From 2009, 141 patients were managed first line with either eBPP (n=52) or eBPDac (n=89) with median follow-up 40 months for eBPP and 12.7 months for eBPDac patients. Patients were well matched with no significant differences in age (median: 28), sex, stage (stage 3/4: 82%) and international prognostic score (IPS3+:65%). More patients treated with eBPDac received only 4 cycles of treatment (43% vs 12%; p Toxicity was compared over the first 4 cycles. There was no difference in day 8 ALT between the two regimens although the mean day 8 neutrophil count was lower in eBPDac than eBPP patients (1.84 vs 2.35; p=0.043; G-CSF given day 9). There was a trend to fewer non-elective days of in-patient care for eBPDac compared with eBPP (mean: 2.78 vs 6.00; p=0.0846), and eBPDac patients received fewer red cell transfusions during cycles 1 to 4 compared with eBPP patients (Mean 1.87 units vs 4.33 units; p 6 months post chemotherapy follow-up had a similar rate of return of menstrual cycles (eBPP: 20/21; eBPDac: 13/16), although eBPDac patients appeared to restart menstruation earlier post chemotherapy completion (mean: 3.85 months vs 8.65 months, p=0.0018). However, this could also reflect the higher mean chemotherapy cycle number completed by the eBPP women (5.86 vs 4.67; p Conclusions Accepting the limitations of a retrospective study, we suggest that substituting dacarbazine for procarbazine is unlikely to compromise the efficacy of eBPP in frontline therapy of patients with advanced Hodgkin Lymphoma and may have some toxicity benefits. As it is highly unlikely that this single drug substitution will ever be tested in a prospective trial, publishing real-world data from eBPDac patients is important. References 1. EuroNet-PHL-C1 study interim report published 14/08/2013 http://www.anzchog.org/docs/public-resources/euronet-recommendation.pdf?sfvrsn=0 2. Borchmann P et al. 2018;390:2790-2802 Disclosures Brice: BMS: Honoraria; Takeda France: Consultancy, Honoraria; Millennium Takeda: Research Funding. Menne:Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel grant; Jazz: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel grant, Research Funding, Speakers Bureau; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Kite/Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel grant, Research Funding, Speakers Bureau; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel grant, Research Funding, Speakers Bureau; Kyowa Kirin: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel grant, Research Funding, Speakers Bureau; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Daiichi Sankyo: Honoraria, Membership on an entity's Board of Directors or advisory committees; Astra Zeneca: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Bayer: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel grant, Research Funding, Speakers Bureau; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel grant, Research Funding, Speakers Bureau; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Osborne:Novartis: Other: Travel; Pfizer: Honoraria, Speakers Bureau; Servier: Consultancy; MSD: Consultancy; Takeda: Consultancy, Honoraria, Other: Travel, Speakers Bureau; Gilead: Consultancy; Roche: Consultancy, Honoraria, Other: Travel, Speakers Bureau. Ardeshna:Gilead: Consultancy, Honoraria; Celgene: Consultancy, Honoraria. Collins:Gilead: Consultancy, Honoraria. Cwynarski:Adienne: Consultancy; Takeda: Consultancy, Other: conference and travel support , Speakers Bureau; Gilead: Consultancy, Other: conference and travel support, Speakers Bureau; Celgene: Consultancy; Roche,: Consultancy, Other: conference and travel support, Speakers Bureau; Autolus: Consultancy; KITE: Consultancy; Atara: Consultancy; Janssen: Other: conference and travel support, Speakers Bureau. Iyengar:Takeda: Honoraria; Janssen: Honoraria; Gilead: Honoraria; Abbvie: Honoraria; Roche: Honoraria. Martinez-Calle:ABBVIE: Other: Travel support. McKay:Epizyme: Consultancy, Honoraria. Nagumantry:Takeda: Honoraria, Speakers Bureau; Alexion: Speakers Bureau; Abbvie: Honoraria. Shah:Abbvie: Consultancy. Uttenthal:Roche: Honoraria; Takeda: Honoraria; Jazz: Honoraria. McMillan:BMS: Honoraria; F. Hoffmann-La Roche Ltd: Honoraria, Speakers Bureau; Sandoz: Honoraria; Celgene: Honoraria, Speakers Bureau; Novartis: Honoraria; Gilead: Honoraria; MSD: Honoraria; Pfizer: Honoraria, Research Funding. Follows:Roche: Consultancy, Honoraria, Speakers Bureau; AZ: Consultancy, Honoraria, Speakers Bureau; Janssen: Consultancy, Honoraria, Speakers Bureau; Abbvie: Consultancy, Honoraria, Speakers Bureau.

Introduction: Predicting the risk of histologic transformation (HT) from indolent follicular lymphoma (FL) to a more aggressive form of lymphoma represents a major challenge in managing patients with FL. We assessed the incidence of HT in the GALLIUM study (NCT01332968) and determined risk factors for transformation and impact on clinical outcomes. Methods: In the Phase III GALLIUM study, patients with previously untreated FL were randomized to receive either the anti-CD20 antibody rituximab (R; 375mg/m² on Day (D) 1 of each cycle) or obinutuzumab (G; 1000mg on D1, 8, and 15 of Cycle 1 and D1 of subsequent cycles) in combination with chemotherapy (CHOP, CVP or bendamustine). Patients who achieved at least a partial response at the end of induction therapy proceeded to maintenance therapy with the same antibody, every 2 months for 2 years, or until progression of disease. Repeat biopsies at progression were not mandatory but carried out in case of clinical suspicion of HT. The rate of HT, as assessed by the local pathologist, in patients with a repeat biopsy at the time of disease progression/relapse was an exploratory endpoint. Results: 1202 patients were enrolled. After a median follow up of 57.3 months, 315 (26.2%) patients progressed (median time to relapse, 25.3 months); of these 315 patients, 46 (14.6%) had a biopsy at first progression due to a clinical suspicion of transformation. Forty patients, corresponding to 3.3% of all patients enrolled in GALLIUM and 12.7% of those that progressed, had biopsy-confirmed HT. Among 153 patients with disease progression within 24 months (POD24), 31/153 (20.3%) had HT. Fewer patients transformed in the G-chemo arm (16/40; 40%) compared with R-chemo (24/40; 60%). In total, 116 patients relapsed in the G-chemo arm versus 159 in the R-chemo arm. Compared with no HT, patients with HT were more likely to be male and have bone marrow involvement, stage 3A FL, high FL International Prognostic Index risk, low hemoglobin (Hb), elevated serum lactate dehydrogenase (LDH), elevated beta-2-microglobulin, and high total metabolic tumor volume (Table). A comparison of chemotherapy backbones showed a trend towards higher HT incidence with bendamustine (5.8% [26/686]) compared with CVP, 4.3% (5/117) and CHOP, 2.3% (9/399). A multivariate cause-specific cox model identified several risk factors for HT, including elevated LDH levels (hazard ratio [HR], 4.27 [95% CI: 2.08─8.78]; p Conclusions: In GALLIUM, a low rate of HT was observed over 5 years, with the majority occurring within the first 2 years. Patients with POD12 had poor OS regardless of whether transformation occurred or not. Risk factors for HT included elevated LDH, anemia, and male gender. Patients with HT, especially those with progression of disease within 24 months, had poor OS compared to patients who relapsed with persistent FL. Disclosures Casulo: Celgene: Research Funding; Gilead: Honoraria, Other: Travel, accommodation, expenses; Roche: Other: Travel, accommodation, expenses. Herold:Roche: Membership on an entity's Board of Directors or advisory committees, Research Funding; GILEAD: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees. Hiddemann:Celgene: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Research Funding; Roche: Consultancy, Honoraria, Research Funding; Gilead: Consultancy, Honoraria; Bayer: Research Funding; Vector Therapeutics: Consultancy, Honoraria. Iyengar:Roche: Honoraria; Abbvie: Honoraria; Gilead: Honoraria; Janssen: Honoraria; Takeda: Honoraria. Marcus:Roche / Genentech: Honoraria, Speakers Bureau; Gilead: Consultancy. Seymour:AbbVie: Consultancy, Honoraria, Research Funding, Speakers Bureau; Takeda: Consultancy; Acerta: Consultancy; Roche: Consultancy, Research Funding, Speakers Bureau; Celgene: Consultancy, Research Funding, Speakers Bureau; Janssen: Consultancy, Research Funding. Launonen:F. Hoffmann-La Roche Ltd: Employment. Knapp:F. Hoffmann-La Roche Ltd: Employment. Nielsen:F. Hoffmann-La Roche Ltd: Employment, Equity Ownership. Mir:Roche: Other: Previous employment.