IBRUTINIB AND RITUXIMAB AS FIRST LINE THERAPY FOR MANTLE CELL LYMPHOMA: A MULTICENTRE, REAL-WORLD UK STUDY

Background: Ibrutinib (IBR) is an oral covalent Bruton tyrosine kinase inhibitor (BTKi), licensed for treatment of relapsed or refractory mantle cell lymphoma (MCL). Under NHS interim Covid-19 agreements in England, IBR with or without rituximab (R) was approved for the frontline treatment for MCL patients (pts) as a safer alternative to conventional immunochemotherapy. Although recent phase 2 studies have reported high response rates in low-risk patients for this combination in the frontline setting, randomised phase 3 and real-world data are currently lacking. Aims: To describe the real-world response rates (overall response rate (ORR), complete response (CR) rate) and toxicity profile of IBR +/-R in adult patients with previously untreated MCL. Methods: Following institutional approval, adults commencing IBR +/-R for untreated MCL under interim Covid-19 arrangements were prospectively identified by contributing centres. Hospital records were interrogated for demographic, pathology, response, toxicity and survival data. ORR/CR were assessed per local investigator according to the Lugano criteria using CT and/or PET-CT. Results: Data were available for 66 pts (72.7% male, median age 71 years, range 41-89). Baseline demographic and clinical features are summarised in Table 1. 23/66 pts (34.8%) had high-risk disease (defined as presence of TP53 mutation/deletion, blastoid or pleomorphic variant MCL, or Ki67%/MiB-1 ≥30%). IBR starting dose was 560mg in 56/62 pts (90%) and was given with R in 22/64 pts (34%). At a median follow up of 8.7 months (m) (range 0-18.6), pts had received a median of 7 cycles of IBR. 19/60 pts (32%) required a dose reduction or delay in IBR treatment. New atrial fibrillation and grade ≥3 any-cause toxicity occurred in 3/59 pts (5.8%) and 8/57 (14.0%) respectively. For the whole population and high-risk pts only, ORR was 74.4% and 64.7% respectively (p=0.2379), with a median time to response of 3.8m, coinciding with the first response assessment scan. Seven pts (16.7%), of whom 2 had highrisk disease, attained CR at a median of 6.0m. ORR for pts receiving vs not receiving R were 84.2% and 66.7% respectively (p=0.1904). IBR was discontinued in 20/61 pts (32.8%) at a median time to discontinuation of 4.1m, due to progressive disease (PD, 19.7%), toxicity (4.9%), death (3.3%;1 pt each of Covid-19 and E. coli infection), pt choice (3.3%) and other unspecified reasons (1.6%). 15/66 pts (22.7%) overall and 7/23 (30.4%) with high-risk disease progressed on IBR at a median time to PD of 4.0m. No pts underwent autologous stem cell transplantation consolidation during the study period. 12/57 pts (21.1%) received second line treatment (R-chemotherapy n=7, Nordic MCL protocol n=2, VR-CAP n=2, pirtobrutinib n=1). Response to second line treatment was CR in 4/11 pts, PD in 7/11. Of the 2 Nordic-treated patients, 1 had CR after cycle 2 and 1 PD. Fourteen pts (21.2%) died during the follow up period, due to MCL (n=11), Covid-19 (n=2) and congestive cardiac failure (n=1). Overall survival was lower for patients with high-risk disease (HR 0.55, p=0.038). Image: Summary/Conclusion: In this real-world UK cohort of pts receiving first-line IBR +/-R for MCL, including older and high-risk pts, we report high ORR rates in a similar range to the phase II Geltamo IMCL-2015 study of combination IBR-R in an exclusively low-risk population. Documented CR rates were lower, possibly reflecting a low usage of rituximab in the Covid-19 pandemic as well as CT assessment of response. Treatment was generally well tolerated, with low rates of toxicityrelated treatment discontinuation. The study is ongoing.

CLL-VR: A UK study of vaccine responses in patients with B-cell chronic lymphocytic leukaemia

B-cell chronic lymphocytic leukaemia (CLL) is associated with immune suppression and patients are at increased risk following SARS-CoV-2 infection. The Chronic Lymphocytic Leukaemia-Vaccine Response (CLL-VR) study was designed to assess immune responses following the introduction of Covid-19 vaccination in UK. Five hundred patients with CLL were recruited nationally through NHS and charity communications. Phlebotomy blood samples were taken from local patients ( n = 100) and dried blood spot samples were collected via post from participants across the UK ( n = 400). Ninety-six age-matched control subjects were also recruited locally. Samples were taken at 2-3 weeks following the first, second and third primary vaccine doses. Antibody and cellular responses against spike protein, and neutralising antibody titre to delta and omicron variant, were measured. Total serum immunoglobulin level was also determined. Responses were analysed according to clinical history, serum immunoglobulin level and vaccine type received. Donors with a clinical or serological history of prior natural infection were excluded from the analysis. Twenty percent (70/353) of participants developed a measurable antibody response after the first vaccination and this increased to 67% (323/486) following the second dose and 80% (202/254) after a third dose. The response rate in healthy controls plateaued at 100% after only two doses. The magnitude of the antibody response was also 3.7-fold lower following the second vaccine compared to controls ( n = 244;490 vs. 1821 U/ml, p < 0.0001) but increased markedly to 3114 U/ ml after third dose ( n = 51). No difference was observed in relation to the initial vaccine platform received. Multivariate analysis on 486 participants showed that BTKi therapy, history of recurrent infection and low serum antibody levels of IgA or IgM were independent prognostic markers for poor antibody response. Among participants with a detectable antibody response, a marked reduction in the ability to neutralise the delta and omicron variants of concern was noted compared to healthy controls following both the second and third dose of vaccine. Cellular responses were assessed following the second vaccine by IFN-g ELISPOT ( n = 91). Patients who had received the ChAdOx1 vaccine had similar levels to controls ( p = 0.39), while those who had received BNT162b2 had lower levels ( p < 0.0001). Five patients with poor spike-specific antibody responses to vaccination subsequently developed breakthrough infection with SARS-CoV-2 delta variant. Antibody responses and neutralisation remained poor following recovery from infection although T-cell responses were strong and only one patient required hospital admission. CLL-VR is the largest vaccine study conducted in patients with CLL and reveals diminished but comparable antibody responses to both the ChAdOx1 and BNT162b2 vaccines with some improvement following third primary dose of mRNA vaccine. In contrast T-cell responses following second dose are greater in those who received ChAdOx1 platform. Low neutralising activity against the delta and omicron variants highlights an ongoing risk for this vulnerable population despite repeated vaccination and reveals the need for alternative approaches to protection including prophylactic monoclonal antibody therapy..

COVID-19 Infection of HSCT Recipients Is Associated with High Mortality but No Detectable Cytokine Storm at Presentation

Introduction The clinical manifestations of COVID-19 infection in recipients of allogeneic hematopoietic stem cell transplantation (HSCT) have been reported in multiple retrospective cohorts of patients, but there have been no prospective studies to date. Previous studies report that HSCT recipients are at higher risk, with cumulative incidence of death between 17-35%. Although an excessive pro-inflammatory viral response has been documented in the general population, its role in the immune incompetent HSCT setting has not been documented. We present a combined prospective and retrospective national study run through the UK IMPACT trial network to characterize the clinical and immunological features of COVID-19 infection in 96 adult and pediatric recipients of HSCT in the United Kingdom. Methods HSCT recipients of any age and transplanted for any indication, with an RT-PCR-proven COVID-19 infection, were eligible for this study. Patients within 72 hours of COVID-19 diagnosis, who had not received cytokine-targeted treatment, were recruited to a prospective cohort. All other patients were eligible for a retrospective cohort. Prospective patients provided blood samples within 72 hours of COVID-19 diagnosis, and again within 72 hours of clinical deterioration (defined as requirement for oxygen administration) if applicable. Follow-up data were collected on patients 30 and 100 days after COVID-19 diagnosis. Results 100 patients were recruited from 16 sites across the UK between May 2020-June 2021, comprising 12 in a prospective cohort and 88 recruited retrospectively. 96 patients were evaluable, as 4 proved ineligible post-registration. Patients were diagnosed with COVID-19 at a median of 11 months after HSCT. Patient/HSCT characteristics are shown Table 1. The most common symptoms associated with the onset of COVID-19 were fever in 8 prospective (73%) and 35 (41%) retrospective patients, followed by cough in 5 (45%) prospective and 35 (41%) retrospective patients and dyspnea in 4 (36%) prospective and 16 (19%) retrospective patients. 8 (73%) prospective and 40 (47%) retrospective patients were actively immunosuppressed at the time of COVID-19 infection. 16% of the patients had moderate/severe disease at baseline. At day 30 (±2 days) after COVID-19 diagnosis, 2 prospective and 8 retrospective patients continued to demonstrate SARS-CoV-2 positivity on respiratory PCR testing. The median time to viral clearance was 40 (IQR 17-78) days for the prospective and 34 (IQR 15-70) days for the retrospective cohort. Prolonged (more than 14 days) neutropenia was reported in 4 (5%) patients in the retrospective cohort, prolonged thrombocytopenia in 2 (18%) prospective and 11 (13%) retrospective patients. 1 retrospective patient developed secondary hemophagocytic lymphohistiocytosis, and graft rejection was reported in 1 (1%) retrospective patient, within 30 days of COVID-19 diagnosis. In the prospective cohort, 3 (27%) patients died, all by day 30, and all due to COVID-19. In the retrospective cohort, 13 (17%) patients died by day 30, rising to 18 (21%) by day 100, 61% of deaths were attributed to COVID-19. Lower baseline platelets (p=0.013, Mann-Whitney U test), lymphocytes (p=0.012), albumin (p=0.028), and higher baseline CRP (p=0.007), were seen in patients who died following COVID-19 diagnosis. Additionally, exploratory univariate logistic regression of the retrospective cohort found mortality at day 100 to be associated with increased age at diagnosis (OR 1.04, 95% CI 1.01-1.08, p=0.04), and no requirement compared with requirement for invasive ventilation (OR 0.02, 95% CI 0.00-0.16, p=0.001). The 11 prospective patients showed normal levels of interleukin (IL)-2, -4, -10, interferon gamma and tumor necrosis factor alpha at COVID-19 presentation. IL-6 was minimally raised (up to 127 pg/ml, nv<50) in 3/11 pts at presentation. Respiratory deterioration was not associated with detectable cytokine storm. Conclusion Our study confirms a significant mortality rate in patients affected by COVID-19 post HSCT and confirms age as well s requirement for invasive ventilation to be independent risk factors associated with death at day 100. Baseline laboratory data at disease presentation can identify patients at higher risk of COVID-19 related death. In the prospective cohort of our study, pathophysiology of the viral disease did not seem related to cytokine storm-mediated inflammation. [Formula presented] Disclosures: Protheroe: Jazz Pharmaceuticals: Honoraria;Astellas: Honoraria;Kite Gilead: Honoraria. Peggs: Autolus: Consultancy, Current equity holder in publicly-traded company. Craddock: Novartis Pharmaceuticals: Other: Advisory Board;Celgene/BMS: Membership on an entity's Board of Directors or advisory committees, Research Funding. Nicholson: BMS/Celgene: Consultancy;Kite, a Gilead Company: Other: Conference fees, Speakers Bureau;Novartis: Consultancy, Other: Conference fees;Pfizer: Consultancy. Amrolia: ADC Therapeutics: Other: Named inventor on a patent which is being transferred to ADCT.;Autolus: Patents & Royalties.

CPX-351 for Acute Myeloid Leukaemia: Real World Results Are Comparable to Trial Outcomes and Exceeds Them in Non-Adverse Risk Patients- a Multicentre Experience from West Midlands Hospitals on Behalf of West Midlands Research Consortium ( WMRC) UK

Patients with secondary AML or MDS derived AML have poor outcomes compared to de-novo AML. The benefits of intensive chemotherapy without anticipated transplant consolidation have been previously doubted. Outcomes in USA trial centres have not often been closely replicable in real world settings. From November 2018 CPX-351 has been available in the UK for secondary AML, therapy related AML, AML with MDS related Karyotype (AML-MRC) and licensed but not funded for AML with myelodysplastic related changes. Objectives Here we report our experience specifically on patient outcomes and toxicity across 5 Hospitals in West Midlands, UK Methods Patients receiving CPX 351 outcomes were evaluated retrospectively from 2018 to 2021. Baseline genetics, CPX 351 indications, patient's comorbidities, overall survival, remission status, number of cycles delivered, early mortality, reasons for early discontinuation, intensive care admission and time for neutrophil recovery (>0.5) was recorded. Time-to-event outcomes reported here are from a data cut on 01-06-21 Results In a total cohort of 57 patients baseline characteristics are shown on table 1 and compared with the original trial CPX-351 group. Median follow up was 376 days (range 21 to 1248 days). The mean age was 63, 17 patients were under 60, 31 males and 26 females. The most common indication for CPX-351 was AML with antecedent MDS/MPN 51% (N=29), therapy related 14% (N=8), MDS related karyotype (AML-MRC) 19% (N=11) and 16% (N=9) other patients. Mean Charleston co-morbidity score was 2.7 (range 0-6), 10.5% (N=6) had previous non myeloid malignancies, 8.7% (N=5) had prior ischaemic heart disease, only 3.5% (N=2) had ejection fractions under 50%. The most common mutations were TP53 21% (N=12), ASXL1 15.7% (N=9), TET2 15.7% (N=9), IDH2 10.5% (N=6), RUNX1 10.5% (N=6), SRSF2 7% (N=4), JAK2 3.5% (N=2), FLT3 5% (N=3), NPM1 5%(N=3) and IDH1 5% (N=3). MRC cytogenetic risk was adverse in 19 patients (33%), intermediate in 35 patients (61%) and favourable in 3 patients (5%). 30 patients (53%) had adverse European Leukaemia Network classification, 17 (30%) had intermediate and 10 (17%) had favourable. 30-day mortality was 3/57 (5%), 60-day mortality was 6 (10.5%) comparable to the 5.9% and 10.6% rates for the original trial. 9% or 5/57 patients were admitted to ITU with 2 survivors beyond 60 days. Neutropenic fever requiring antibiotics was 100% whereas only 5/57 (9%) had radiological evidence of fungal infection. Only one patient died from COVID 19. The mean time to neutrophil recovery was 35 days with a range of 12 to 84 days. 29 patients completed 1 cycle, 25 completed 2 cycles, only 3 completed 3 cycles. The reasons for stopping were death, refractory disease, drop in performance status, alternative chemotherapy chosen or moving to transplantation (39%). Composite remission rate including CRi was 61% 36/57, adverse ELN group demonstrated 50% 15/30, intermediate 76% 13/17 and favourable 80% 8/10. Mutated P53 was associated with a 50% 6/12 rate whereas in wild type P53 the remission rate was 60% 30/45. Overall median survival from diagnosis was 429 days [95% CI 274 to 788 days]. To compare with the original trial, we removed the under 60s and those with less than 1 year follow up, in this cohort of 30 patients the median survival was 289 days (9.5 months) with 95% CI of 255 to 476 days. P53 mutated patients had an estimated median survival of 257 days versus wild type p53 with 524 days hazard ratio of 2.418 (CI 1.077 to 5.248) with p value of 0.032. Median survival for ELN groups was 373 days (adverse), 413 days (intermediate) and not reached for favourable. Of the 36 patients who achieved a remission, 22 went on to receive an allogenic transplant with follow from 254 to 1248 days, median survival estimated 706 days (95% CI 429-not reached). Patients in remission who haven't received a transplant have a similar estimated survival of 788 days (305-not reached) pending longer follow up. Conclusion This is the first UK multicentre analysis to show comparable results to the landmark trial ( edian survival 9.5 months in equivalent cases). The improved overall remission rate 61% versus the 47% in the trial and the longer median survival 14 months versus 9.5 months in the trial is expected given the younger age and increase in favourable risk genetics. This study therefore supplies further data of CPX-351 efficacy in younger patients not included in the original studies and may now be used as a standard comparator arm. [Formula presented] Disclosures: No relevant conflicts of interest to declare.

Vaccine Efficacy after Rituximab Exposure: First Interim Analysis of Virtue Project on Behalf of West Midlands Research Consortium, UK

[Formula presented] Background: Anti-CD20 B cell depleting agents are amongst the most commonly used immunotherapeutics employed in the treatment of haematological malignancy and autoimmune diseases. By inducing peripheral B cell aplasia, anti-CD20 depleting agents are hypothesised to significantly impair serological responses to neoantigens, including the SARS-CoV-2 spike glycoprotein within SARS-CoV-2 vaccines. Seropositivity following SARS-CoV-2 is the strongest, measurable correlate of protection from severe COVID-19. Understanding the kinetics of B cell reconstitution and vaccine responsiveness following exposure to B cell depleting agents is essential to maximise vaccine efficacy in patients vulnerable to severe COVID-19. Methods: 80 patients with underlying haematological malignancy and 38 patients with underlying rheumatological disease previously treated with anti-CD20 B cell depleting agents were studied following their second dose of a SARS-CoV-2 vaccine (median time to sampling: 46.5d, IQR: 33.8-63.3). Lymphocyte subset (CD4, CD8, CD19, CD56/16) enumeration was performed using 6 colour flow cytometry (BD Trucount). Total anti-SARS-CoV-2 spike glycoprotein antibodies were measured by enzyme-linked immunosorbent assay (The Binding Site, Human Anti-IgG/A/M SARS-CoV-2-ELISA). The relationship between immune reconstitution following B cell depletion and vaccine responsiveness was explored. Results: In the haematology cohort (median age 70y, IQR 60.3-76.0, 62.5% male), overall seropositivity following vaccination was 60.0%. Individuals on active chemotherapy had significantly lower seroprevalence than those vaccinated following the completion of chemotherapy (22.7% vs 74.1%, p<0.0001). In the rheumatology cohort (median age 65y, IQR 58.3-70.8, 39.9% male), overall seropositivity was 69.4%. In both cohorts, vaccine non-responders had significantly smaller populations of peripheral CD19+ B cells (haematology: 0.20 vs 0.02 x10 9/L, p=0.004, rheumatology: 0.07 vs 0.01 x10 9/L, p=0.03). The magnitude of the antibody response following vaccination did not differ between recipients of Tozinameran and Vaxzeveria in either cohort. Vaccine responsiveness was lower in the first 6 months following B cell depletion therapy;42.9% in the haematology cohort and 33.3% in the rheumatology cohort, increasing to 100% and 75% respectively in individuals receiving their second dose 6-12 months following B cell depletion (Figure 1). B cell reconstitution in the 7-12 month window following B cell depletion was faster in haematology compared to rheumatology patients (77.8% v 22.2% achieving normal B cell count, p=0.005) and associated with improved vaccine responsiveness. However, persistent immunodeficiency occurred in some haematology patients following completion of treatment: 25% of patients who had completed therapy at least 36 months previously failed to respond to vaccination. In this cohort of vaccine non-responders, 83.3% of individuals had B cell numbers within the normal range. These patients had all previously been treated for follicular lymphoma suggesting a specific mechanism for long-range secondary immunodeficiency in these patients. Conclusions: Serological responsiveness to SARS-CoV-2 vaccines is poor during active chemotherapy for haematological malignancy and in the first 6 months following B cell depletion, regardless of underlying disease. Vaccine responsiveness significantly improves in the 7-12 month window following B cell depletion. Compared to haematology patients, B cell reconstitution is slower in rheumatology patients and associated with reduced vaccine responsiveness, possibly due to the use of additional concurrent disease-modifying anti-rheumatic therapies. Furthermore, long-term secondary immunodeficiency occurs in a minority of haematology patients. To maximise the efficacy from SARS-CoV-2 booster vaccination and optimal utilisation of available vaccine doses, immunisations should be delivered at least 6 months following the administration of anti-CD20 depleting drugs. Figure 1: Kinetics of return f vaccine responsiveness following B cell depletion in haematology and rheumatology patients. [Formula presented] Disclosures: Paneesha: Roche: Honoraria;Janssen: Honoraria;Gilead: Honoraria;Bristol Myers Squibb: Honoraria;AbbVie: Honoraria;Celgene: Honoraria. Drayson: Abingdon Health: Current holder of individual stocks in a privately-held company.

Ibrutinib Plus Rituximab Is Superior to FCR in Previously Untreated CLL: Results of the Phase III NCRI FLAIR Trial

Introduction: The most effective chemoimmunotherapy (CIT) in previously untreated CLL is the combination of fludarabine, cyclophosphamide and rituximab (FCR). Ibrutinib (I), the first irreversible inhibitor of Bruton's tyrosine kinase approved for CLL, has improved outcomes in numerous clinical trials compared to different CIT. Methods: FLAIR (ISRCTN01844152) is an ongoing, phase III, multicentre, randomised, controlled, open, parallel group trial for previously untreated CLL requiring therapy according to the IWCLL 2008 guidelines. Patients over 75 years or with >20% 17p-deleted cells were excluded. Participants were randomised on a 1:1 basis to receive 6 cycles of FCR (oral fludarabine 24mg/m 2/day for 5 days, oral cyclophosphamide 150mg/m 2/day for 5 days with IV rituximab [375 mg/m 2 on day 1/2 of cycle 1;500 mg/m 2 on day 1 of cycles 2-6]) every 28-days or IR (Ibrutinib [420mg/day] plus rituximab [6 doses as for FCR]) given for up to 6 years with stratification by disease stage, age, gender and centre. The primary endpoint was to assess whether IR was superior to FCR in terms of investigator-assessed PFS. Secondary endpoints included overall survival,;attainment of undetectable MRD;response to therapy;safety and toxicity;health-related quality of life and cost-effectiveness. A formal interim analysis was planned when 191 events were observed in both arms or 109 events in the FCR arm alone with a p-value of 0.005 leading to reporting of the trial. Here we report the results of this planned interim analysis. Results: A total of 771 patients were randomised (385 to FCR and 386 to IR) from 113 UK Centres between 9/19/2014 and 7/19/2018. The data was locked on 5/24/2021. 73.3% were male, median age was 62 years (33.6% >65yo) and 45.1% were Binet Stage C. IGHV data was available for 728 (94.4%) patients with 53.2% IGHV unmutated (≥98% homology to germline), 40.5% IGHV mutated and 6.3% Subset 2. Hierarchical FISH testing revealed 0.4% 17p del, 15.4% 11q del, 12.3% trisomy 12, 29.7% normal and 35% 13q del;with 7.1% failed. The arms were well-balanced for disease variables with no significance differences. Median follow-up was 52.7 months. IR had a superior PFS compared to FCR (Median PFS not reached for IR versus 67 months for FCR;HR: 0.44;p<0.001;see Figure). The PFS was significantly better for IR in patients with IGHV unmutated CLL (HR: 0.41;p<0.001), but not for patients with IGHV mutated CLL at this follow-up (HR: 0.66;p=0.179). There was no difference in overall survival between the two arms (HR: 1.01;p=0.956) with a total of 29 deaths in FCR arm (including 4 from CLL, 3 Richter's [RT], 3 AML/MDS, 3 COVID-19 and 2 cardiac/sudden) and 30 in the IR arm (including 3 CLL, 1 RT, 0 AML/MDS, 3 COVID-19 and 8 cardiac/sudden). Second line treatment was initiated for 59 patients after FCR (including 38 BTKi, 7 venetoclax+R [venR], 4 BendamustineR [BR] and 3 CHOP-R [RT]) and 21 after IR (including 7 FCR, 5 venR, 1 BR, 1 CHOP-R [RT], 1 ABVD [Hodgkin's]). Overall, 88.1% of patients have received targeted therapies for CLL progression after FCR. The overall survival with FCR in FLAIR is significantly improved compared to FCR in previous NCRI trials (ADMIRE and ARCTIC) which had the same inclusion criteria, the same Centres and an identical FCR schedule, but were conducted prior to widespread availability of targeted therapies in the relapse (recruited between 2009 and 2012). The 4 year overall survival for FCR in FLAIR was 94.5% compared to 84.2% for FCR between 2009 and 2012. SAEs were reported in 53.7% of patients on FCR and 53.4% on IR. Notable differences for SAEs by organ class for FCR vs IR: infections in 33.6% of patients vs 27.1%;blood and lymphatic in 19.8% vs 10.7%;and cardiac in 1.1% vs 8.3%. With current follow-up, there were 10 sudden or cardiac deaths: 8 IR and 2 FCR. Further analysis indicated that 7 of the 8 cardiac or sudden deaths in the IR arm had a history of hypertension or cardiac disease (further detailed in additional ;Munir et al.). Neither of the sudden deaths in the FCR arm ad a prior cardiac or hypertensive history or were on cardiac or anti-hypertensive treatment. There were 6 cases of secondary MDS/AML in the FCR arm and 1 in the IR arm. Conclusion: Ibrutinib plus rituximab resulted in a superior PFS compared to FCR. There was no difference in overall survival, most likely due to effective second-line targeted therapy in patients progressing after FCR. [Formula presented] Disclosures: Hillmen: Janssen: Honoraria, Other: Travel, Accommodations, Expenses, Research Funding;AbbVie: Honoraria, Other: Travel, Accommodations, Expenses, Research Funding;Pharmacyclics: Honoraria, Research Funding;Roche: Research Funding;Gilead: Research Funding;SOBI: Honoraria;BeiGene: Honoraria;AstraZeneca: Honoraria. Bloor: Novartis: Honoraria;Kite, a Gilead Company: Honoraria. Broom: AbbVie: Honoraria;AstraZeneca: Honoraria;Janssen-Cilag Ltd: Honoraria;Takeda UK Ltd: Honoraria;Celgene Ltd: Honoraria;Gilead: Honoraria. Furtado: Abbvie: Other: Conference support. Morley: Kite: Honoraria;Janssen: Honoraria;AbbVie;Takeda: Other: Conference support;Roche: Membership on an entity's Board of Directors or advisory committees, Other: Conference support. Cwynarski: Adienne, Takeda, Roche, Autolus, KITE, Gilead, Celgene, Atara, Janssenen: Other. Paneesha: Celgene: Honoraria;Roche: Honoraria;Janssen: Honoraria;Gilead: Honoraria;Bristol Myers Squibb: Honoraria;AbbVie: Honoraria. Howard: Roche: Current Employment. Cairns: Merck Sharpe and Dohme: Research Funding;Amgen: Research Funding;Takeda: Research Funding;Celgene / BMS: Other: travel support, Research Funding. Patten: NOVARTIS: Honoraria;ROCHE: Research Funding;JANSSEN: Honoraria;ASTRA ZENECA: Honoraria;ABBVIE: Honoraria;GILEAD SCIENCES: Honoraria, Research Funding. Munir: F. Hoffmann-La Roche: Consultancy;Alexion: Honoraria.

Antibody responses after first and second Covid-19 vaccination in patients with chronic lymphocytic leukaemia.

B-cell chronic lymphocytic leukaemia (CLL) is associated with immunosuppression and patients are at increased clinical risk following SARS-CoV-2 infection. Covid-19 vaccines offer the potential for protection against severe infection but relatively little is known regarding the profile of the antibody response following first or second vaccination. We studied spike-specific antibody responses following first and/or second Covid-19 vaccination in 299 patients with CLL compared with healthy donors. 286 patients underwent extended interval (10-12 week) vaccination. 154 patients received the BNT162b2 mRNA vaccine and 145 patients received ChAdOx1. Blood samples were taken either by venepuncture or as dried blood spots on filter paper. Spike-specific antibody responses were detectable in 34% of patients with CLL after one vaccine (n = 267) compared to 94% in healthy donors with antibody titres 104-fold lower in the patient group. Antibody responses increased to 75% after second vaccine (n = 55), compared to 100% in healthy donors, although titres remained lower. Multivariate analysis showed that current treatment with BTK inhibitors or IgA deficiency were independently associated with failure to generate an antibody response after the second vaccine. This work supports the need for optimisation of vaccination strategy in patients with CLL including the potential utility of booster vaccines.