Safety and Efficacy of AUTO1, a Fast-Off Rate CD19 CAR in Relapsed/Refractory B-Cell Non-Hodgkin's Lymphoma (B-NHL) and Chronic Lymphocytic Leukaemia (CLL)

INTRODUCTION We have previously described AUTO1, a CD19 CAR with a fast off-rate CD19 binding domain, designed to reduce CAR-T immune toxicity and improve engraftment. Its clinical activity has been tested in r/r paediatric and adult B-ALL. Cumulatively, this data confirms the intended function of the receptor, with low levels of CRS/ICANS and long-term engraftment of CAR T-cells observed in both patient groups. Recently, CAR-T therapy has been explored in indolent lymphomas such as follicular (FL) and mantle cell lymphoma (MCL), but a high incidence of toxicity including Grade 3-4 ICANS has been reported. We have initiated testing of AUTO1 in the setting of indolent and high-grade B-NHL and CLL (NCT02935257). METHODS Manufacturing: CAR T-cell products were generated using a semi-automated closed process from non-mobilised leukapheresate. Study design: Subjects ≥ 16y underwent lymphodepletion with fludarabine (30mg/m 2 x3) and cyclophosphamide (60mg/kg x1) prior to AUTO1 infusion, with the exception of the DLBCL cohort who additionally received a single dose of pembrolizumab (200mg) on day -1 to potentiate CAR-T expansion. AUTO1 dose varies based on the indication. Split dosing of 230 x10

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.

Steroid Use, Advanced Stage Disease and ≥3 Lines of Prior Chemotherapy Are Associated with a Higher Risk of Infection Following CD19 CAR T-Cell Therapy for B-NHL: Real World Data from a Large UK Center

Background: Tisagenlecleucel (Tisagen) and Axicabtagene Ciloleucel (Axicel) CD19 CAR T-cell products are licensed in the UK for adults with relapsed/refractory high-grade B-cell Non-Hodgkin's lymphoma (B-NHL). Infection rates for the first 30 days post CAR T range from 23% (Hill et al, Blood 2018) to 42% (Park et al, Clin Infect Dis 2018) with a predominance of early bacterial infections. Infection etiology is multifactorial, including pre-existing immunosuppression, poor marrow reserve, concomitant disease, delayed cytopenias and lymphodepletion. CRS has been shown to be an independent risk factor and associated treatment (Tocilizumab, steroids) may contribute. Risk assessment is limited by heterogenous cohorts in published reports and practice variations in use of prophylactic antibiotics and intravenous immunoglobulin (IVIG). To determine incidence and outcome of infection with licensed CAR T-cell products, we conducted a retrospective review at UCLH, London, UK. Methods: Electronic medical records were used to collect data on patients treated with Tisagen/Axicel from May 2019 to July 2020. Infections at ≤28 days and >28days following infusion were recorded. Infections were defined as a positive microbiological/virology result in conjunction with clinical symptoms. Invasive fungal infections were classified according to revised EORTC criteria. Infections were graded as severe (requiring systemic treatment) or life threatening (hypotension/organ support). Results: Sixty adults with B-NHL received Tisagen (n=19) or Axicel (n=41). Patients did not receive prophylactic antibiotics. IVIG was given for hypogammaglobulinaemia with recurrent infections (n=4). Within 28 days of infusion, 44 episodes of infection occurred in 28 patients (47%). Post day 28 (range 29-452), 19 episodes occurred in 9 patients (15%). Severe (n=9) and life-threatening (n=7) infection occurred in 15% and 12% of patients respectively, with two infections resulting or contributing to death (3.3%). Infections were bacterial (56%), respiratory viral (24%), other viral (14%) and fungal (6%). Six (10%) developed viral reactivations;CMV (n=1), BK virus in blood or urine (n=2), HHV6 (n=1) or AdV (n=2). PCR proven JC virus causing progressive multifocal leukoencephalopathy was reported in 1 patient at day 116. Only one late COVID-19 infection occurred despite the program remaining operational throughout lockdown. There was no association between early infection and CRS severity (p=0.43), or use (p=0.94) and dose of Tocilizumab (p=0.54). With regard to pre-treatment variables, advanced disease at time of infusion (≥stage 3) was associated with higher risk of any infection (OR 4.2, 95% CI 1.3- 13.4, p=0.016) and lines of prior therapy (≥3) with higher risk of early infection (OR 3.0, 95% CI 1.0-8.9, p=0.048). Steroid treatment was associated with a higher risk of early (and overall) infection (OR 3.0. 95% CI 1.0-8.6, p=0.048). A diagnosis of ICANS was associated with infection beyond day 30 (p=0.021). In multivariate analyses, steroid use (p=0.03) and ≥3 lines of prior therapy (p=0.021) were associated with infection ≤28 days of infusion. Steroid use (p= 0.049) and stage pre infusion (p=0.023) were associated with higher risk of any infection. Conclusion: In this real world analysis of B-NHL patients treated with Tisagen or Axicel, 47% developed early infection at ≤28 days. Severe or life-threatening infection occurred in 27% of patients. Multivariate analysis confirms significant association with (1) steroid exposure (2) ≥stage 3 disease and (3) ≥3 lines of previous therapy. There was no overt association with Tocilizumab use or CRS severity. Unlike other centers, our cohort did not receive prophylactic antibiotics or IVIG. Patients with advanced disease are high risk for CRS, ICANS and infectious complications. Risk modification strategies include bridging optimization to reduce disease burden pre CAR T with infectious prophylaxis from referral until at least 3-6 months post-infusion. In this analysis, steroids represent a significant ri k and efforts should be made to wean doses swiftly. The use of steroid sparing agents such as Anakinra may be important (clinical trial results awaited). In ≥ stage 3 disease or heavily pre-treated patients, there may be a role for prophylactic antibiotics but this should be explored within a clinical study with consideration of local antimicrobial resistance patterns. Disclosures: Neill: Novartis: Other: Funded attendance at academic conferences;Celgene: Other: Funded attendance at academic conferences. Townsend: Roche, Gilead: Consultancy, Honoraria. Ardeshna: Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees;Beigene: Membership on an entity's Board of Directors or advisory committees;Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees;Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees;ADC Therapeutics: Membership on an entity's Board of Directors or advisory committees;Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees;Sanofi, Genzyme, AstraZeneca: Speakers Bureau;University College London (UCL)/UCL Hospitals (UCLH) Biomedical Research Unit: Other: Supported by this organisation. Cwynarski: Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Travel Support, Speakers Bureau;Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees;Atara: Consultancy, Membership on an entity's Board of Directors or advisory committees;Gilead: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau;KITE: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Travel Support, Speakers Bureau;Roche: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Travel Support, Speakers Bureau;Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Travel Support. Peggs: Autolus: Consultancy. Roddie: Celgene: Honoraria;Gilead: Honoraria;Novartis: Honoraria. O'Reilly: Gilead: Honoraria;Novartis: Honoraria, Other: Travel support.