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

Patients with previous CD19 directed chimeric antigen receptor T cell therapy (CAR T)-cell therapy have a prolonged vulnerability to viral infections. Coronavirus diseases 2019 (COVID-19) has a great impact and has previously been shown to cause high mortality in this population. Until now, real world data of the impact of vaccination and treatment on patients with COVID-19 after CD19 directed CAR T-cell therapy are lacking. Therefore, this multicenter retrospective study was conducted with data from the EPICOVIDEHA survey. Sixty-four patients were identified. The overall mortality caused by COVID-19 was 31%. Patients infected with the Omicron variant had a significantly lower risk of death due to COVID-19 compared to patients infected with previous variants (7% versus 58% (P=0.012)). Twenty-six patients were vaccinated at time of COVID-19 diagnosis. Two vaccinations showed marked but unsignificant reduction risk of COVID-19 caused mortality (33.3% versus 14.2% (P=0.379)).Also the course of disease appears milder with less frequent ICU admissions (39% versus 14% (P=0.054)) and shorter duration of hospitalization (7 versus 27.5 days (P=0.022)). Of the available treatment options, only monoclonal antibodies seemed to be effectively reducing mortality from 32% to zero (P=0.036). We conclude that survival rates of CAR T-cell recipients with COVID-19 improved over time and that the combination of prior vaccination and monoclonal antibody treatment significantly reduces their risk of death.

Patients receiving chimeric antigen receptor T cells (CAR-T cells) therapy may be particularly susceptible to coronavirus disease 2019 (COVID-19) because of several factors including the immunosuppression associated to the underlying disease and delayed cytopenias. Regrettably, data on outcomes of CAR-T recipients with COVID-19 are extremely scarce. The aim of this study was to investigate the characteristics and outcomes of COVID-19 in patients treated with CAR-T therapy. The European Hematology Association - Scientific Working Group Infection in Hematology endorsed a survey to collect and analyze data from patients developing COVID-19 after CAR-T therapy. Overall, 459 patients treated with CAR-T cells were reported from 18 European centers. The prevalence of COVID-19 cases was 4.8%. Median time from CAR-T therapy and COVID-19 diagnosis was 169 days. Severe infection occurred in 66.7% of patients and 43.3% of the subjects required admission to ICU. The COVID-19 mortality was 33%. In multivariable analysis, the disease status at the time of COVID-19 trended marginally towards adverse outcome (P=0.075). In conclusion, we documented a high fatality rate for CAR-T patients with COVID-19, supporting the need to design successful interventions to mitigate the risk of infection in this vulnerable group of patients.

The use of novel small molecule inhibitors alone or in combination with anti-CD20 monoclonal antibodies for chronic lymphocytic leukemia (CLL) has raised a number of questions on efficacy, tolerability, long-term treatment adherence in patients with heterogeneous clinical features. To fill this gap, we designed a study focusing on treatment sequencing in patients with CLL in order to (i) compare the outcome of patients treated with chemoimmunotherapy (CIT) combinations in first-line versus those receiving Bruton's tyrosine kinase inhibitors (BTKi); (ii) characterize the efficacy and tolerability of venetoclax-based regimens; (ii) understand the impact of treatment sequencing when it comes to chemo-free options including venetoclax after BTKi and vice versa. Data from consecutive sets of patients diagnosed with CLL between 2000-2020 attended at 77 institutions affiliated with ERIC were collected and analyzed. Collected variables included: demographics, clinical stage at diagnosis, IGHV gene somatic hypermutation status; cytogenetic status for chromosomes 11q, 13q 17p and 12 determined by fluorescence in situ hybridization; TP53 gene mutation status; treatment; treatment response; discontinuation; reason for discontinuation; death. We included 9173 patients with a diagnosis of CLL who received at least one line of treatment. The median age at diagnosis was 67 years with a male:female ratio of 1.9. The median follow-up was 78 months (IQR, 48-120 months). Regarding novel targeted agents, 1860/9173 (20.2%) patients had received at least one line of treatment with BTKi (ibrutinib, n=1788; acalabrutinib, n=72) over the disease course; 631/9173 (6.9%) with venetoclax; and, 447/9173 (4.9%) with the PI3K inhibitor idelalisib. Seventy-nine patients were treated with both BTKi and venetoclax (59 BTKi followed by BCL2i, 20 vice versa). At last follow-up, 5870/9173 patients (64.0%) were alive, 3229/9173 (35.2%) died and 74/9173 (0.8%) were lost to follow-up. Patients treated with BTKi in first-line were enriched for TP53 aberrations [del(17p) 27.6%, TP53 mutation 26.3%] and unmutated IGHV genes (69%) and obtained an ORR of 87.7%. Of these, 136 (26.3%) discontinued treatment after a median of 1.2 years (0.07-5.98); main reasons of discontinuation were toxicity (40.5%) and failure (26.2%). Among 631 patients treated with venetoclax at any line, 100 (15.8%) received BCL2 +/- anti-CD20 as first-line; 170 (26.9%) as second line (125 previously treated with CIT, 27 with BTKi); and, 361 as third or subsequent line. ORR ranged between 71.5% (≥3 lines) with 30.5% CR/CRi to 90.3% (first-line) with 68.1% CR/CRi. Treatment discontinuation was due to toxicity in 28.6% of patients treated in the first-line, and 17.6% and 21.8% of patients treated in second and third-or-higher-line, respectively. Disease progression led to treatment discontinuation in 14.3%, 20.6% and 33.6% in first, second and third-or-higher line, respectively. CIT was used as front-line treatment in 5465 patients (59.6%). Of these, 2070 (37.9%) and 1018 (18.6%) patients received a second and third line of treatment, respectively. The great majority (865/1086 cases, 79.7%) of patients who received a second line before 2014 were retreated with CIT, most commonly Bendamustine-Rituximab (284/1086, 26.1%) and Fludarabine-Cyclophosphamide-Rituximab (252/1086, 23.2%); alemtuzumab monotherapy was used in 55/1086 (5%) of patients. After 2014, 415/984 patients (42.1%) were retreated with BTKi; 93 (9.5%) with venetoclax; 70 (7.2%) with idelalisib; 50 (5%) with Alemtuzumab monotherapy, and 315 (32%) with CIT. Similarly, in the third-or-higher line of treatment, most patients (86.3%) were retreated with CIT before 2014, while BTKi, BCL2i, and PI3Ki were mainly used after 2014 (in 43.1%, 15.7% and 14.7% of cases, respectively). Finally, our cohort included 1075 patients with TP53 aberrations. The ORR of patients receiving BTKis (n=171) as first-line of treatment was 86.5% (22.2 CR+64.3 PR), while the ORR with venetoclax +/- anti-CD20 (n=15) was 91% (45.5% CR+45.5 PR). Patients treated with CIT (n=694) had an ORR of 68.7% (28.3% CR+40.4% PR). In conclusion, in a large international study we provide real world data regarding the selection and sequencing of treatment in CLL, charting a major shift in treatment patterns before and after the introduction of novel trargeted agents and confirming their efficacy even in high-risk CLL. Disclosures Scarfo: Janssen: Honoraria, Other: Travel grants; Astra Zeneca: Honoraria; Abbvie: Honoraria. Iacoboni: BMS/Celgene, Gilead, Novartis, Janssen, Roche: Honoraria. Collado: Abbvie,: Other: pharmaceutical Company, Research Funding; Janssen: Other: Pharmaceutical Company, Research Funding. Galimberti: AbbVie, Janssen: Honoraria, Other: Travel grants; Incyte: Speakers Bureau. García-Serra: AbbVie: Other: Educational grands; Janssen: Other: Educational grants; Novartis: Other: Educational grants. Gozzetti: Janssen: Honoraria; AbbVie: Honoraria. Hatzimichael: Amgen, Roche, Genesis, Novartis, Bristol Mayer Squibb, Celgene, Pfizer: Consultancy; Abbvie, Amgen, Bristol Mayer Squibb, MSD, Gilead, Janssen Cilag, Genesis Pharma, Roche, Takeda: Honoraria. Herishanu: AbbVie: Honoraria, Research Funding; Janssen: Honoraria; Roche: Honoraria; Medison: Honoraria. Jaksic: Roche, Oktal-Pharma/Celtrion, Sandoz: Consultancy, Honoraria. Kater: Janssen, AstraZeneca: Other: Ad Board, steering committee, Research Funding; Abbvie: Honoraria, Other: Ad Board, Research Funding; BMS, Roche/Genentech: Other: Ad Board, , Research Funding; Genmab, LAVA: Other: Ad Board, Steering Committee. Kotsianidis: Astellas: Other: NONE, Research Funding, Speakers Bureau; Genesis: Consultancy, Other: NONE; Janssen Hellas: Consultancy, Other: NONE, Speakers Bureau; Bristol Hellas: Consultancy, Other: NONE, Research Funding, Speakers Bureau; Novartis Hellas: Consultancy, Other: NONE, Research Funding, Speakers Bureau; Abbvie: Consultancy, Other: NONE, Research Funding, Speakers Bureau. Kreitman: NIH: Patents & Royalties: Moxetumomab Pasudotox; Genentech: Research Funding; Teva: Research Funding; AstraZeneca/MedImmune: Research Funding; Innate: Research Funding; GSK/Novartis: Research Funding; Array BioPharma/Pfizer: Research Funding. Laribi: BeiGene: Other: Personal Fees; Jansen: Research Funding; Novartis: Other: Personal Fees, Research Funding; Astellas Phama, Inc.: Other: Personal Fees; AstraZeneca: Other: Personal Fees; Le Mans Hospital: Research Funding; Takeda: Other: Personal Fees, Research Funding; AbbVie: Other: Personal Fees, Research Funding; IQONE: Other: Personal Fees. Lopez-Garcia: Roche: Other: Speaker Honoraria, Travel and accommodation grants; Novonordisk: Other: Speaker Honoraria; Fresenius: Other: Speaker Honoraria; Celgene: Other: Speaker Honoraria; Abbvie: Other: Speaker Honoraria, Advisor, Travel and accommodation grants; Janssen: Other: Speaker Honoraria, Advisor, Travel and accommodation grants, Research Funding. Milosevic: Roche: Honoraria; Abbvie,: Honoraria; Janssen: Honoraria; Sandoz: Honoraria. Reda: Beigene: Consultancy; Astra Zeneca: Consultancy; Abbvie: Consultancy; Janssen: Consultancy. Ruchlemer: AbbVie: Consultancy, Honoraria, Research Funding. Šimkovič: Janssen, Gilead, Roche, AstraZeneca, and AbbVie: Other: consultancy fees, advisory board participation fees, travel grants, and honoraria; University Hospital Hradec Kralove: Current Employment; AbbVie: Consultancy, Current equity holder in publicly-traded company, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses; AstraZeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen-Cilag: Consultancy, Honoraria, Other: Travel, Accommodations, Expenses; Merck: Current equity holder in publicly-traded company; Eli Lilly: Current equity holder in publicly-traded company; J&J: Current equity holder in publicly-traded company; Gilead: Other: Travel, Accommodations, Expenses. Špaček: AbbVie, AstraZeneca, Gilead, Janssen, and Roche: Honoraria. Tadmor: Janssen: Consultancy, Honoraria, Research Funding; AbbVie: Consultancy, Honoraria, Research Funding. Visentin: Italfarmaco and Gilead: Speakers Bureau. Vassilakopoulos: AstraZeneca: Honoraria; Amgen: Honoraria, Research Funding; Pfizer: Research Funding; Dr. Reddy's: Research Funding; Novartis: Consultancy, Honoraria; GlaxoSmithKline: Honoraria, Other: Travel; Merck: Honoraria, Research Funding; Integris: Honoraria; Roche: Consultancy, Honoraria, Other: Travel; Genesis Pharma: Consultancy, Honoraria, Other: Travel; Takeda: Consultancy, Honoraria, Other: Travel, Research Funding; AbbVie: Consultancy, Honoraria; Karyopharm: Research Funding. Vitale: Janssen: Honoraria. Yáñez: Gilead-Kite, Janssen, AbbVie, AstraZeneca, Beigene, Roche, Pfizer, Jazz, BMS, and Merck: Other: Advisory board participation fees ; Janssen, AbbVie, AstraZeneca, Gilead-Kite, Roche, Pfizer, and Merck: Speakers Bureau. Antic: AbbVie, Janssen, and Roche: Honoraria. Coscia: Janssen: Honoraria, Other, Research Funding; Gilead: Honoraria; AstraZeneca: Honoraria; AbbVie: Honoraria, Other. Cuneo: AstraZeneca: Consultancy, Speakers Bureau; Janssen: Consultancy, Speakers Bureau; Gilead: Consultancy, Speakers Bureau; AbbVie: Consultancy, Speakers Bureau. Gaidano: Beigene: Membership on an entity's Board of Directors or advisory committees; Incyte: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Astrazeneca: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Guièze: Janssen: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria, Research Funding; Roche: Consultancy, Honoraria; Astrazeneca: Consultancy, Honoraria. Laurenti: AstraZeneca: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria, Research Funding; Roche: Honoraria, Research Funding; Gilead: Honoraria; Janssen: Consultancy, Honoraria; BeiGene: Honoraria. Murru: Abbvie: Consultancy, Honoraria, Other: travel and accommodation; Janssen: Consultancy, Honoraria. Sportoletti: AstraZeneca: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria. Tam: Beigene: Research Funding; Janssen: Research Funding; Abbvie: Research Funding; Loxo: Honoraria; Beigene: Honoraria; Janssen: Honoraria; Abbvie: Honoraria. Trněný: Amgen: Consultancy, Honoraria; Bristol-Myers Squibb: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses; Gilead Sciences: Consultancy, Honoraria, Other: Travel, Accommodations, Expenses; Incyte: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses; MorphoSys: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses; Celgene: Consultancy; 1st Faculty of Medicine, Charles University, General Hospital in Prague: Current Employment; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Portola: Honoraria, Membership on an entity's Board of Directors or advisory committees; AstraZeneca: Honoraria; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses. Bosch Albareda: Janssen: Consultancy, Honoraria, Research Funding, Speakers Bureau; Gilead: Consultancy, Honoraria; Abbvie: Consultancy; AstraZeneca: Consultancy, Honoraria, Research Funding; Roche: Consultancy, Honoraria, Research Funding, Speakers Bureau; Takeda: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Kite: Honoraria; Sanofi: Honoraria; Lilly: Honoraria. Doubek: Janssen-Cilag, AbbVie, AstraZeneca, Amgen, Gilead, Novartis: Honoraria, Research Funding. Chatzidimitriou: Abbvie: Honoraria, Research Funding; Janssen: Honoraria, Research Funding. Ghia: AbbVie: Consultancy, Honoraria, Research Funding; Acerta/AstraZeneca: Consultancy, Honoraria, Research Funding; AstraZeneca: Consultancy, Honoraria, Research Funding; ArQule/MSD: Consultancy, Honoraria; BeiGene: Consultancy, Honoraria; Celgene/Juno/BMS: Consultancy, Honoraria; Gilead: Consultancy, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Roche: Consultancy, Honoraria; Sunesis: Research Funding. Stamatopoulos: AstraZeneca: Honoraria, Research Funding; Abbvie: Honoraria, Research Funding; Gilead: Honoraria, Research Funding; Janssen: Honoraria, Research Funding.

Prophylactic high-dose methotrexate (HD-MTX) is often used for diffuse large B-cell lymphoma (DLBCL) patients at high risk of central nervous system (CNS) relapse, despite limited evidence demonstrating efficacy or the optimal delivery method. We conducted a retrospective, international analysis of 1384 patients receiving HD-MTX CNS prophylaxis either intercalated (i-HD-MTX) (n = 749) or at the end (n = 635) of R-CHOP/R-CHOP-like therapy (EOT). There were 78 CNS relapses (3-year rate 5.7%), with no difference between i-HD-MTX and EOT: 5.7% vs 5.8%, P = .98; 3-year difference: 0.04% (−2.0% to 3.1%). Conclusions were unchanged on adjusting for baseline prognostic factors or on 6-month landmark analysis (n = 1253). In patients with a high CNS international prognostic index (n = 600), the 3-year CNS relapse rate was 9.1%, with no difference between i-HD-MTX and EOT. On multivariable analysis, increasing age and renal/adrenal involvement were the only independent risk factors for CNS relapse. Concurrent intrathecal prophylaxis was not associated with a reduction in CNS relapse. R-CHOP delays of ≥7 days were significantly increased with i-HD-MTX vs EOT, with 308 of 1573 (19.6%) i-HD-MTX treatments resulting in a delay to subsequent R-CHOP (median 8 days). Increased risk of delay occurred in older patients when delivery was later than day 10 in the R-CHOP cycle. In summary, we found no evidence that EOT delivery increases CNS relapse risk vs i-HD-MTX. Findings in high-risk subgroups were unchanged. Rates of CNS relapse in this HD-MTX-treated cohort were similar to comparable cohorts receiving infrequent CNS prophylaxis. If HD-MTX is still considered for certain high-risk patients, delivery could be deferred until R-CHOP completion.

Patients with chronic lymphocytic leukemia (CLL) may be more susceptible to Coronavirus disease 2019 (COVID-19) due to age, disease, and treatment-related immunosuppression. We aimed to assess risk factors of outcome and elucidate the impact of CLL-directed treatments on the course of COVID-19. We conducted a retrospective, international study, collectively including 941 patients with CLL and confirmed COVID-19. Data from the beginning of the pandemic until March 16, 2021, were collected from 91 centers. The risk factors of case fatality rate (CFR), disease severity, and overall survival (OS) were investigated. OS analysis was restricted to patients with severe COVID-19 (definition: hospitalization with need of oxygen or admission into an intensive care unit). CFR in patients with severe COVID-19 was 38.4%. OS was inferior for patients in all treatment categories compared to untreated (p

Introduction Coronavirus disease 2019 (COVID-19) is a life-threatening condition of high relevance for co-morbid patients, such as those with baseline hematological malignancies (HM). One year after the diagnosis of the first COVID-19 case, at the end of 2020, the first vaccines against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were administered to the population, starting with individuals at highest risk of infection. EPICOVIDEHA aims to describe the epidemiology, vaccination strategies and mortality rates from HM patients at risk. Methods We collected clinical and epidemiological data from patients with laboratory-based diagnosis of SARS-CoV-2 infection after partial or complete vaccination. The study was sponsored by the European Hematology Association - Infectious Diseases Working Party. Patients were registered in the EPICOVIDEHA online survey between January 1, 2021 and July 31, 2021 from Europe and United States. Data captured included underlying conditions prior to SARS-CoV-2, HM status and management prior to SARS-CoV-2, SARS-CoV-2 vaccination and infection details and mortality. The survey will continue until December 31, 2021. Results Overall, 40 patients have been so far registered, 24 male and 16 females, the vast majority of them aged over 50 years (N=38, 95%). Three quarters of patients were affected by lymphoproliferative malignancies (chronic lymphoid leukemia [CLL] N=14 and non-Hodgkin lymphoma [NHL] and multiple myeloma [MM] N=8, each), followed by myelodysplastic syndrome (MDS) (N=4), acute myeloid leukemia (AML) (N=2) and others (chronic myeloid leukemia [CML], acute lymphoid leukemia [ALL], polycythemia vera [PV] and aggressive mastocytosis one of each). Thirty-one patients (77.5%) were receiving active treatment for underlying HM at the time of SARS-CoV-2 infection, with 16 of them being on chemotherapy in the month prior to infection. All patients were vaccinated with a median time from vaccine to SARS-CoV-2 infection of 45.5 days (IRQ 19-67.5). Twenty-nine patients received a mRNA vaccine (BioNTech/Pfizer N=28, Moderna COVE N=1), whereas the remaining 11 an inactivated vaccine (Sinovac CoronaVac N=6) and vector-based vaccine (AstraZeneca Oxford N=5). Twenty-three patients were completely vaccinated, of which 22 (97.5%) patients were immunized (a minimum of 15 days following second dose). On the contrary, among 17 patients partially vaccinated, none was immunized. In 9 cases, viral genomes were analyzed (English variant N=7, South Africa variant N=1, Indian variant N=1). Overall, 25/40 patients presented with a severe/critical infection (62.5%), 13 of which (52%) were fully vaccinated and immunized, whereas only 15 (37.5%) were asymptomatic or mildly symptomatic. Twenty-seven (92.5%) patients were admitted to hospital, 5/27 (18.5%) to ICU, all requiring mechanical ventilation. After a follow-up of 30 day from SARS-CoV-2 infection, 8 patients died (20%), with 7/8 deaths (87.5%) attributable to SARS-CoV-2. There was no difference in overall survival between those patients that received 2 doses of vaccine or 1 dose (figure 1a), as well as no difference being observed between patients with and without lymphoproliferative malignancies (figure 1b), patients that receiving/not receiving active treatment in the last month (figure 1c), or the type of vaccine injected (figure 1d). Conclusions Our survey, involving over 150 Hematology Departments around the world, provides some preliminary insights. The majority of patients who do not respond to vaccination are patients with lymphoproliferative diseases, as can also be observed for other types of vaccination (e.g., flu-vaccination). Dramatically the mortality observed in all patients, although lower than that observed in the pre-vaccination period which in our experience was around 31%, still remains high (20%). Recruitment to this survey continues, and we hope that with larger numbers of cases, more definitive conclusions can be drawn to develop strategies to keep these complex patients safe. Figure 1 Figure 1. Disclosures Lopez-Garcia: Celgene: Other: Speaker Honoraria; Abbvie: Other: Speaker Honoraria, Advisor, Travel and accommodation grants; Janssen: Other: Speaker Honoraria, Advisor, Travel and accommodation grants, Research Funding; Roche: Other: Speaker Honoraria, Travel and accommodation grants; Novonordisk: Other: Speaker Honoraria; Fresenius: Other: Speaker Honoraria. Glenthoej: Novo Nordisk: Honoraria; Agios: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; bluebird bio: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Alexion: Research Funding. Mikulska: Biotest: Speakers Bureau; Janssen: Speakers Bureau; MSD: Speakers Bureau; Gilead: Speakers Bureau; Pfizer: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Busca: Gilead Sciences: Other: Lecture Honoraria; Merck: Other: Lecture Honoraria; Pfizer Pharmaceuticals: Other: Lecture Honoraria; Basilea: Other: Lecture Honoraria; Biotest: Other: Lecture Honoraria; Jazz Pharmaceuticals: Other: Lecture Honoraria; Takeda: Membership on an entity's Board of Directors or advisory committees. Corradini: KiowaKirin; Incyte; Daiichi Sankyo; Janssen; F. Hoffman-La Roche; Kite; Servier: Consultancy; AbbVie, ADC Theraputics, Amgen, Celgene, Daiichi Sankyo, Gilead/Kite, GSK, Incyte, Janssen, KyowaKirin, Nerviano Medical Science, Novartis, Roche, Sanofi, Takeda: Honoraria; AbbVie, ADC Theraputics, Amgen, Celgene, Daiichi Sankyo, Gilead/Kite, GSK, Incyte, Janssen, KyowaKirin, Nerviano Medical Science, Novartis, Roche, Sanofi, Takeda: Consultancy; Amgen; Takeda; AbbVie: Consultancy, Honoraria, Other: Travel and accommodations; Novartis; Gilead; Celgene: Consultancy, Other: Travel and accommodations; BMS: Other: Travel and accommodation; Sanofi: Consultancy, Honoraria; Incyte: Consultancy; Novartis, Janssen, Celgene, BMS, Takeda, Gilead/Kite, Amgen, AbbVie: Other: travel and accomodations. Hoenigl: Gilead, Pfizer, Astellas, Scynexis, and NIH: Research Funding. Klimko: Gilead Science, MSD, Pfizer: Membership on an entity's Board of Directors or advisory committees; Gilead Sciences, MSD, Pfizer Pharmaceuticals, and Astellas Pharma: Speakers Bureau. Pagliuca: Gentium/Jazz Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Gilead, Pfizer, and MSD: Research Funding. Passamonti: Celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; AbbVie: Speakers Bureau; BMS: 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. Köhler: German Federal Ministry of Research and Education and the State of North Rhine-Westphalia, Germany: Other: Support; Miltenyi Biotec GmbH, Bergisch Gladbach, Germany, and the Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany: Other: Non-financial grants; Akademie für Infektionsmedizin e.V., Ambu GmbH, Astellas Pharma, European Confederation of Medical Mycology, Gilead Sciences, GPR Academy Ruesselsheim, MSD Sharp & Dohme GmbH, Noxxon N.V., and University Hospital, LMU Munich: Consultancy, Honoraria. Cornely: Amplyx, Basilea, BMBF, Cidara, DZIF, EU-DG RTD (101037867), F2G, Gilead, Matinas, MedPace, MSD, Mundipharma, Octapharma, Pfizer, Scynexis: Other: Grants or Contracts. Pagano: Gilead Science, MSD, Pfizer, Basilea, Janssen, Novartis, Jazz Pharmaceutical, Cidara: Membership on an entity's Board of Directors or advisory committees; Gilead Sciences, MSD, Pfizer Pharmaceuticals, Astellas Pharma: Speakers Bureau; Menarini: Consultancy.

Introduction: Central nervous system (CNS) relapse in diffuse large B-cell lymphoma (DLBCL) is uncommon but is associated with poor outcomes. In selected high risk patients (pts), high dose methotrexate (HDMTX) is often used as CNS prophylaxis with frontline (1L) DLBCL therapy despite uncertain efficacy, optimum dose and timing of delivery. A recent UK study (Wilson et al 2020) showed that intercalated HDMTX (i-HDMTX) was associated with increased toxicity and R-CHOP delays compared to end of treatment (EOT) delivery. Although hypothesis generating, the study size was insufficient to determine whether EOT was non-inferior in terms of CNS relapse risk. Methods: We conducted an international, multicentre retrospective analysis of consecutive DLBCL or high grade BCL pts between 2007-20 from 47 centers in Europe, Australia and N. America. Pts were included if they received R-CHOP or R-CHOP-like 1L therapy with curative intent as well as HDMTX CNS prophylaxis (≥1 cycle). Concurrent intrathecal (IT) prophylaxis was permitted. Pts with known CNS involvement at baseline and those treated with more intensive protocols (e.g. R-DA-EPOCH) were excluded. i-HDMTX was defined as any pt receiving a HD-MTX cycle before the final R-CHOP cycle. CNS relapse events were excluded if occurring after first systemic lymphoma relapse/progression. Time to event endpoints were measured from diagnosis to first event or censor and analysed using Kaplan-Meier and Cox regression methods. Time to CNS relapse was analysed using competing risk Fine and Gray method (for death and non-synchronous systemic relapse). To mitigate for possible immortality bias in the EOT arm, a landmark analysis for pts alive and free from progression at 6 months was conducted. We aimed to exclude a 5% difference in 2-year (y) CNS relapse rates. Results: 1,384 pts were analysed. 750 received i-HDMTX and 634 received EOT HDMTX. Key baseline characteristics are summarised in Table 1. Median follow up was 37.9 months. 44.2% had high CNS IPI (4-6) with no significant difference between i-HDMTX and EOT groups (45.1% vs 43.1%, p=0.087). ≥2 cycles of HDMTX were used in 86.6% with no difference between groups (85.6% vs 87.9%, p=0.22). Concurrent IT prophylaxis use was higher for EOT pts (55.6% vs 38.1% p 78 CNS relapses (42 i-HDMTX, 36 EOT) were observed: parenchymal in 41 (53%), parenchymal and leptomeningeal in 16 (21%) and isolated leptomeningeal in 21 (27%). There was no significant difference in 2y CNS relapse rates between i-HDMTX and EOT in all pts: 5.2% vs 3.9%, adjusted hazard ratio (HR) 0.92 (95% CI 0.58-1.47), p=0.74, 2y difference -0.2% (-2.0-2.5) or landmark analysis: 2.8% vs 4.1%, HR: 0.93 (0.56-1.55), p=0.79, 2y difference: -0.3% (-1.8-2.2%) (Fig 1a/b). Exploratory analyses focusing on pts with isolated CNS relapse (n=57) demonstrated similar results (2y rates 3.6% vs 3.0%, p=0.99). On multivariable analysis (MVA) of risk factors for CNS relapse, renal/adrenal involvement was the only variable associated with increased CNS relapse risk (adjusted HR 1.74 (1.03-2.92), p=0.038). Notably, IT prophylaxis was not associated with reduction in CNS relapse. In 600 high CNS IPI (4-6) pts, there was no difference in CNS relapse risk between i-HD-MTX and EOT (3y rates 9.4% vs 8.6%, HR 0.92 (95% CI 0.52-1.62)). In a composite high risk group including CNS IPI 4-6 and/or any of the following: ≥3 extranodal sites, renal, adrenal, testicular or breast involvement (n=885) there was no difference in 3y CNS relapse rates between groups (i-HDMTX 7.6% vs EOT 7.4%, HR 0.94 (0.58-1.53)). Progression-free survival (PFS) and overall survival (OS) in the i-HDMTX and EOT groups were as follows: 3y PFS 70.7% vs 76.7% (p=0.098), 3y OS 79.9% vs 87.0% (p=0.0016). However, there were no PFS/OS differences between groups on landmark analysis (n=1259) (Fig 1c). On analysis of pts experiencing ≥1 R-CHOP delay of ≥7 days, use of i-HDMTX was the only factor on MVA associated with increased delays (p Discussion: We found no evidence that EOT delivery increases CNS relapse risk when compared to i-HDMTX in this large analysis of pts treated with 1L R-CHOP. Delays to R-CHOP cycles were increased with i-HDMTX. Findings in a high risk subgroup were unchanged and rates of CNS relapse in this HDMTX treated group were similar to published comparable high risk cohorts receiving infrequent CNS prophylaxis. Where HDMTX prophylaxis is used, delivery could be deferred until R-CHOP completion. Figure 1 Figure 1. Disclosures Wilson: Takeda: Other: Conference fees; Janssen: Other: Conference fees; Abbvie: Honoraria. Eyre: Janssen: Honoraria; Secura Bio: Consultancy, Honoraria; Gilead/KITE: Honoraria, Other: Travel support for conferences, Research Funding, Speakers Bureau; Roche: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria, Other: Travel to conferences; AstraZeneca: Honoraria, Research Funding; Loxo Oncology: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Incyte: Consultancy; Beigene: Honoraria, Research Funding. Ahearne: Pfizer: Research Funding; Takeda: Honoraria; Roche: Honoraria. Schorb: Roche: Research Funding; Riemser Pharma GmbH: Honoraria, Research Funding; AbbVie: Research Funding. Ku: Antegene: Consultancy; Roche: Consultancy; Genor Biopharma: Consultancy. Narkhede: Genentech/Roche: Research Funding; Gilead: Research Funding; Genmab: Other: Medical writing support, Research Funding; TG Therapeautics: Research Funding. Lewis: AstraZeneca: Consultancy, Honoraria; Janssen: Honoraria, Patents & Royalties; Novartis: Patents & Royalties; Roche: Consultancy, Honoraria. Øvlisen: Abbvie: Other: Travel expenses. Santarsiere: Janssen: Honoraria. Shah: Abbvie, Janssen and Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees. Roulin: Janssen: Other: Travel and meetings. Manos: Bristol-Myers Squibb: Other: Travel and meetings. Hamad: Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Lopez-Garcia: Roche: Other: Speaker Honoraria, Travel and accommodation grants; Janssen: Other: Speaker Honoraria, Advisor, Travel and accommodation grants, Research Funding; Abbvie: Other: Speaker Honoraria, Advisor, Travel and accommodation grants; Celgene: Other: Speaker Honoraria; Fresenius: Other: Speaker Honoraria; Novonordisk: Other: Speaker Honoraria. El-Galaly: ROCHE Ltd: Ended employment in the past 24 months; Abbvie: Other: Speakers fee. Cheah: Beigene: Consultancy, Honoraria, Other: advisory; AbbVie: Research Funding; Celgene: Research Funding; AstraZeneca: Consultancy, Honoraria, Other: advisory; Loxo/Lilly: Consultancy, Honoraria, Other: advisory; TG Therapeutics: Consultancy, Honoraria, Other: advisory; Roche: Consultancy, Honoraria, Other: advisory and travel expenses, Research Funding; Janssen: Consultancy, Honoraria, Other: advisory; MSD: Consultancy, Honoraria, Other: advisory, Research Funding; Gilead: Consultancy, Honoraria, Other: advisory; Ascentage pharma: Consultancy, Honoraria, Other: advisory. Ferreri: Gilead, Novartis, Juno, PletixaPharm, Roche, Incyte: Membership on an entity's Board of Directors or advisory committees; BMS, Beigene, Pharmacyclics, Hutchison Medipharma, Amgen, Genmab, ADC Therapeutics, Gilead, Novartis, Pfizer: Research Funding. Fox: Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Other: speaker fees. Cwynarski: Gilead: Consultancy, Speakers Bureau; Incyte: Consultancy, Speakers Bureau; Atara: Consultancy; Celgene: Consultancy; Takeda: Consultancy, Other: travel to scientific conferences, Speakers Bureau; Kite, a Gilead Company: Consultancy, Other: travel to scientific conferences, Speakers Bureau; Janssen: Consultancy, Other: travel to scientific conferences; Roche: Consultancy, Other: travel to scientific conferences, Speakers Bureau; BMS/Celgene: Other: travel to scientific conferences. 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.