CD19-directed CAR T-cell Therapy Research Articles

CD22-directed CAR T-cell therapy for large B-cell lymphomas progressing after CD19-directed CAR T-cell therapy: a dose-finding phase 1 study

CD22-directed CAR T-cell therapy for large B-cell lymphomas progressing after CD19-directed CAR T-cell therapy: a dose-finding phase 1 study

CD19/BCMA dual-targeting FasTCAR-T GC012F for patients with relapsed/refractory B-cell non-Hodgkin lymphoma: An update.

e19045 Background: CD19-directed CAR-T cell therapy has been demonstrated to be a valuable treatment option for relapsed/refractory B-cell non-Hodgkin’s lymphoma (r/r B-NHL). It has been shown that between 39% and 97% of clinical samples of B-NHL also express BCMA. To further improve safety and efficacy, we have developed GC012F, a CD19 and BCMA dual-targeting CAR-T, manufactured using the novel next-day FasT CAR-T process, for the treatment of r/r B-NHL. The data from an investigator-initiated trial of GC012F for r/r B-NHL were reported at ASCO 2023 (# 7562). Here, we present updated results of the trial, including more pts and a longer follow-up period. Methods: This is a single-arm, open label trial (ChiCTR2100047061). The patients (pts) were enrolled and treated with a single infusion of GC012F in escalating dosing cohorts after a standard lymphodepletion regimen. The primary objectives of this study were safety and tolerability; the secondary were pharmacokinetics and efficacy. Cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) were graded by ASBMT 2019, adverse effects were evaluated according to CTCAE 5.0. Efficacy assessment of GC012F was referred to the Lugano criteria. Results: As of data cut-off on January 30th, 2024, with a median of 410.5 days (range: 28 - 839) of follow-up, all pts received single GC012F infusions at dose levels ranging from 3.7×104 to 3×105 CAR-T/kg. The median age was 49.5 years (range: 18 - 67). Ten pts were Ann Arbor stage III/IV disease. All pts lymphoma samples expressed CD19, and 9 out of 11 expressed BCMA. Ptsreceived a median of 2 prior lines (range: 2 - 3) of therapy including rituximab and anthracyclines. Two ptsreceived the auto-HSCT previously. 91.7% (11/12) of the pts achieved ORR at month 3 post GC012F infusion; 66.7% (8/12) CR at month 6 and 60% (6/10) CR at month 12, respectively. To date, the longest duration of remission is 27.0 months. No dose-limiting toxicities were observed. One pt had grade 3 CRS and recovered within 2 days. No ICANS were observed. Grade ≥ 3 hematologic toxicities included lymphocytopenia (11/12), neutropenia (11/12) and leukopenia (10/12). All TEAEs were resolved after treatment with standard of care and supportive care. The median peak copy number of CAR-T cells in the peripheral blood was 70,083 copies/μg DNA (range: 6,876 - 185,039), and the median peak time was 14 days (range: 9 - 21). CAR-T cells were also detected in tumor biopsies from all six pts tested. In five pts at progressive disease, the primary or new lesions were CD19 positive, and no CAR-T cells were detected. Conclusions: This first-in-human trial of GC012F for the treatment of r/r DLBCL showed a manageable safety profile and promising clinical responses and a long-lasting duration of a remission. Overall, CD19-BCMA dual targeting CAR-T product GC012F is a promising therapy for r/r DLBCL pts and longer follow-up is ongoing. Clinical trial information: ChiCTR2100047061 .

Optimization of older adults by a geriatric assessment–guided multidisciplinary clinic before CAR T-cell therapy

AbstractThe optimal means of assessing candidacy of older adults (≥65 years) for chimeric antigen receptor T-cell (CAR-T) therapy are unknown. We explored the role of a geriatric assessment (GA)–guided multidisciplinary clinic (GA-MDC) in selecting and optimizing older adults for CAR-T. Sixty-one patients were evaluated in a GA-MDC (median age, 73 years; range, 58-83). A nonbinding recommendation (“proceed” or “decline”) regarding suitability for CAR-T was provided for each patient based on GA results. Fifty-three patients ultimately received CAR-T (proceed, n = 47; decline, n = 6). Among patients who received B-cell maturation antigen (BCMA)–directed (n = 11) and CD19-directed CAR-T (n = 42), the median overall survival (OS) was 14.2 months and 16.6 months, respectively. GA uncovered high rates of geriatric impairment among patients proceeding to CAR-T therapy, with fewer impairments in those recommended “proceed.” Patients recommended “proceed” had shorter median length of stay (17 vs 31 days; P = .05) and lower rates of intensive care unit admission (6% vs 50%; P = .01) than those recommended “decline.” In patients receiving CD19- and BCMA–directed CAR-T therapy, a “proceed” recommendation was associated with superior OS compared with “decline” (median, 16.6 vs 11.4 months [P = .02]; and median, 16.4 vs 4.2 months [P = .03], respectively). When controlling for Karnofsky performance status, C-reactive protein, and lactate dehydrogenase at time of lymphodepletion, the GA-MDC treatment recommendation remained prognostic for OS (hazard ratio, 3.26; P = .04). Patients optimized via the GA-MDC without serious vulnerabilities achieved promising outcomes, whereas patients with high vulnerability experienced high toxicity and poor outcomes after CAR-T therapy.

388 Prototyping a mobile phone application for Chimeric Antigen Receptor (CAR) T-cell therapy patient monitoring and data collection post-discharge

OBJECTIVES/GOALS: Research objectives include prototyping a mobile phone application that allows physicians to monitor CD19-directed CAR T-cell therapy patients remotely after discharge. This app will also enable standardized data collection across different centers that provide CAR-T cell therapy and allow for the harmonization of follow-up protocols. METHODS/STUDY POPULATION: Literature review and semi-structured interviews with patients, clinical coordinators, and other experts in the field will be used to determine what parameters must be included in the mobile application prototype to effectively monitor the side effects of CD19-directed CAR T-cell therapy. The mobile phone application will be designed using process mapping to integrate data from self-reporting and wearable technologies, including the Garmin smart watch. Figma will then be used to develop new screens based on an existing patient monitoring app for Allogeneic Stem Cell Transplant follow-up. Finally, a preliminary feasibility study will be conducted to collect feedback on the app prototype from CAR T-cell therapy patients, providers, and stakeholders. RESULTS/ANTICIPATED RESULTS: The anticipated results of this study include an app prototype that will include the functionalities required to monitor patients for adverse effects of CD19-directed CAR T-cell therapy. This will include the parameters that will be recorded or measured using a combination of self-reporting, a reliable body temperature sensor, and the Garmin watch which monitors basic vitals, activity, and sleep. Additional parameters may be added during the stakeholder co-design process. The app prototype will include a physician interface where doctors can monitor their patients and will be alerted if they require further physician assessment. It is expected that the app will provide standardized monitoring of patients when they are discharged from the hospital after receiving CAR T-cell therapy. DISCUSSION/SIGNIFICANCE: This app will allow physicians to monitor patients for general follow-up and adverse effects, including cytokine release syndrome and neurotoxicity. Future studies may utilize this app to develop best practices for harmonizing CAR-T follow-up protocols across Canada.

Real World Outcomes for AYA Patients with Relapsed/Refractory B-Cell ALL Receiving CD19-Directed CAR T-Cell Therapy

Real World Outcomes for AYA Patients with Relapsed/Refractory B-Cell ALL Receiving CD19-Directed CAR T-Cell Therapy

Applying the EHA/EBMT grading for ICAHT after CAR-T: comparative incidence and association with infections and mortality

AbstractCytopenias represent the most common side effect of CAR T-cell therapy (CAR-T) and can predispose for severe infectious complications. Current grading systems, such as the Common Terminology Criteria for Adverse Events (CTCAE), neither reflect the unique quality of post–CAR-T neutrophil recovery, nor do they reflect the inherent risk of infections due to protracted neutropenia. For this reason, a novel EHA/EBMT consensus grading was recently developed for Immune Effector Cell-Associated HematoToxicity (ICAHT). In this multicenter, observational study, we applied the grading system to a large real-world cohort of 549 patients treated with BCMA- or CD19-directed CAR-T for refractory B-cell malignancies (112 multiple myeloma [MM], 334 large B-cell lymphoma [LBCL], 103 mantle cell lymphoma [MCL]) and examined the clinical sequelae of severe (≥3°) ICAHT. The ICAHT grading was strongly associated with the cumulative duration of severe neutropenia (r = 0.92, P < .0001), the presence of multilineage cytopenias, and the use of platelet and red blood cell transfusions. We noted an increased rate of severe ICAHT in patients with MCL vs those with LBCL and MM (28% vs 23% vs 15%). Severe ICAHT was associated with a higher rate of severe infections (49% vs 13%, P < .0001), increased nonrelapse mortality (14% vs 4%, P < .0001), and inferior survival outcomes (1-year progression-free survival: 35% vs 51%, 1-year overall survival: 52% vs 73%, both P < .0001). Importantly, the ICAHT grading demonstrated superior capacity to predict severe infections compared with the CTCAE grading (c-index 0.73 vs 0.55, P < .0001 vs nonsignificant). Taken together, these data highlight the clinical relevance of the novel grading system and support the reporting of ICAHT severity in clinical trials evaluating CAR-T therapies.

Therapeutic options for large B-cell lymphoma relapsing after CD19-directed CAR T-cell therapy.

In recent years, chimeric antigen receptor T-cell therapy (CART) has revolutionized the treatment landscape for large B cell lymphoma (LBCL), demonstrating remarkable efficacy and ushering a new era of therapeutic possibilities. However, a subset of patients may not achieve the desired response with CAR T. This review examines strategies aimed at optimizing outcomes for patients who relapse or progress after CAR T. Available data on utilization of CD19-directed monoclonal antibodies and antibody drug conjugates have shown limited efficacy in this setting. Moreover, bispecific antibodies have also emerged as an alternative therapy in relapsed and or refractory LBCL, but long-term follow up treated cases post-CAR T failure are lacking. Several observational studies have shown efficacy of allogeneic hematopoietic cell transplantation, but attainment of a complete remission prior to allografting is a prerequisite to achieve durable remissions. As we navigate the intricate landscape of treatment of post CAR T failure, it becomes evident that this represents a therapeutic challenge which necessitates a multifaceted approach.

Reinfusion of Varnimcabtagene Autoleucel (IMN-003A) in Patients with Relapsed Refractory B Cell Malignancies Is Feasible with Sustained Responses

Background: Varnimcabtagene autoleucel, a CD19 directed CAR-T cell therapy with a 4-1BB co-stimulatory domain and a non-FMC63 based murine scFv (A3B1 binder), has demonstrated remarkable responses in relapsed/refractory B cell malignancies (RR BCM) in the IMAGINE study. Reinfusion of var-cel is an option to improve functional persistence for CD19+ relapsed disease. This abstract describes the clinical outcomes following reinfusion of var-cel in patients (pts) who relapsed after first infusion. Methods: Patients (pts) aged 3 to 45 years (B-ALL) and ≥ 18 years (B-NHL) with RR BCM were eligible for IMAGINE study if they had measurable disease, as assessed by lymphoid blasts (B-ALL) or metabolic tumour bulk (B-NHL), received ≥1 prior regimen, refractory to the last line of treatment with good performance status (ECOG 0 to 1). The primary target dose was 1x10 6/kg CAR+ cells (B-ALL) and 5x10 6/kg CAR+ cells (B-NHL) (overall range 0.1x10 6 to 5x10 6) and was infused over 3 days (10%/30%/60% fractions). Primary objectives were overall response rate (ORR: CR + CRi in B-ALL and CR + PR in B-NHL) at day +90 after first infusion, and safety. Response was assessed as per NCCN (B-ALL) and IWG (B-NHL) criteria. Adverse events (AEs) were graded using CTCAE v5.0. CRS and ICANS were graded according to ASTCT criteria. Criteria for reinfusion was: 1) achieved response with subsequent disease progression and presence of CD19 positive malignant cells; 2) available second dose for retreatment from initial apheresis and manufacturing run; and 3) after primary endpoint at D+90. This abstract evaluates the outcomes at D+28 after var-cel reinfusion. Results: At data cut-off, 25 pts were enrolled (median age 31 yrs, range 3 - 66) with RR BCM (n=13 B-ALL; n=12 B-NHL). 24 pts received var-cel (1 withdrawal) with majority of infusions on Days 0, +3, +7. ORR was 91.7% at D+28 and 80.9% at D+90. Median progression free survival (PFS, range 12-NR), duration of response (DOR, range 0-NR) and overall survival (OS) were not reached (range 12-NR). Nine pts had relapsed disease (37.5%) with median PFS of 178 days (range 28-319). Of these 9 pts, 7 had CD19+ relapse (77.8%) and 2 (with B-ALL) had CD19- relapse. Four of these pts received second infusion at full dose (same as primary infusion) fractionated over 3 days (10%, 30%, 60%). For these 4 pts, duration of B cell aplasia after primary infusion was 90 days to NR (range); var-cel was detectable in 1 pt (n=1/4) at relapse; and median PFS was 166 days (range 90-275). Tumour burden at relapse was: Ph+ B-ALL (n=1) with 22% blasts (p210 BCR ABL transcript 36.7%); B-NHL (n=3) with TMTV range 7.5 to 277 ml and SPD range 660.5 to 8686 mm 2 (Table 1). PDL1 exhaustion marker was expressed in one B-NHL pt only. Salvage regimen in B-NHL pts was involved field radiotherapy (n=2); 1 B-NHL pt was reinfused without salvage treatment. B-ALL pt received Dasatinib, Inotuzumab and CNS prophylaxis. Preparative conditioning regimen for these 4 patients were: Fludarabine-Cyclophosphamide (n=1), with Rituximab (n=2) and Rituximab with Nivolumab (n=1). Post reinfusion, var-cel was not detected in 1 pt (B-ALL) however B cell aplasia was persistent. In B-NHL pts, Cmax range was 7222 to 31846 CAR+ copies / ug genomicDNA; Tmax was D+2 after reinfusion and duration of var-cel persistence was range 2 days to NR (Figure 1). Post reinfusion, no CRS (0%) or ICANS (0%) was reported. Hematotoxicity was the most common AE (100%) with neutropenia (G3+ 100%); anemia (G3+ 66.7%); and thrombocytopenia (G3+ 33.3%;). Hypogammaglobulinemia (IgG &amp;lt;4g/L) was seen in 2 pts (50%, new onset 1 pt). Time to first response after reinfusion was 28 days. The D+28 ORR for evaluable pts (n=2) was 100%. Median PFS after reinfusion is NR. Post reinfusion 1 pt (Ph+ B-ALL) died of disease progression at 313 days (50 days after reinfusion). The evaluable B-NHL pts are in remission. Conclusions: Reinfusion of varnimcabtagene autoleucel (IMN-003A) is feasible, safe and well tolerated. Preparative conditioning regimen for reinfusion needs personalization guided by CAR persistence, disease biology (CD20, PDL1 expression) and haematological reserve. After reinfusion, prolonged B cell aplasia was observed with 100% ORR at D+28 in evaluable pts. Var-cel was detected post reinfusion in B-NHL patients with sustained responses. Reinfusion may be considered in preference for some pts. The ideal preparative regimen and pt characteristics to guide reinfusion outcomes remains an area of research.

Disease Control Affects Outcomes of Patients with Relapsed Diffuse Large B Cell Lymphoma Treated with CD19 Directed CAR T-Cell Therapy

Introduction: CAR T-cell therapy against CD19 (CART-19) has become the standard of care for pts with primary refractory or relapsed diffuse large B-cell lymphoma (DLBCL) in the second and third line settings. The use of CART-19 therapy improves clinical outcomes compared to standard chemotherapy-based salvage regimens. However, DLBCL pts with disease progression following CART-19 therapy have poor overall survival (OS). Identifying biomarkers associated with improved outcomes can inform the optimal timing for CART-19 implementation. We report the impact of disease control at the time of CART-19 therapy on clinical outcomes. Methods: We conducted a retrospective study of relapsed/refractory (r/r) DLBCL treated at our institution with commercial CART-19 products between 4/2018 and 2/2023. Clinical, pathologic, and pharmacologic (type of bridging, lymphodepletion) characteristics were collected. PET/CT imaging prior to CART-19 therapy was used to determine pretreatment disease status (CR, PR or chemo-resistant disease). Treatment outcomes included best response to CART-19 therapy, frequency and severity of adverse events (CRS or ICANS), PFS and OS. Associations with clinical outcomes were evaluated using logistic regression models by Firth's method. Odds ratios [OR] and 95% CI were obtained. OS and PFS were summarized via Kaplan-Meier method; estimates of median 6- and 12-m rates were obtained with 95% CI. Associations with OS and PFS were evaluated using Cox regression models. Analyses were conducted in SAS v9.4; significance level 0.05. Results: 94 pts were included in this study. Median age was 64 yrs [range 22-81]; 66% were male; 90% Caucasian. Comorbidity index [assessed by HCT-CI] was 2+ in 51.7% pts. Median time from CART-19 discussion to re-infusion was 3.1 m [range 0.2-80 m]. Based on PET/CT scan assessment prior to CART-19 therapy, 9.6% pts achieved CR to bridging, 19% had PR, 64% were resistant (SD or PD). High risk IPI score was present in 23.4%. 14.9% pts had prior ASCT. FluCy lymphodepletion was given in 83% pts. Best response to CART-19 therapy: CR 45.7%, PR 12.8%. PD and SD observed in 28.7% and 3.2% of pts respectively. At median follow up of 36.5 m, median PFS was 6.7 m [95% CI 3.8-18.4]; median OS was 16.0 m [95% CI 9.8-30.6]. Any grade CRS occurred in 61.7%; Grade 3+ CRS 8.5%. Any grade ICANS occurred in 45.7%; Grade 3+ ICANS 16%. Second cancers occurred in 9.6%; 4 pts developed MDS. Adequate disease control at the time of CART-19 therapy was associated with improved ORR (P=0.028). Lack of disease control determined by PET/CT at the time of CART-19 infusion correlated unfavorably with OS and PFS. Pts with chemoresistant disease at the time of CART-19 therapy had a median survival of 7.2 m [HR 2.07 (0.74-5.79)] compared to pts in CR or PR at the time of CART-19 (median survival 27.9 m and 26.8 m respectively, p=0.023). Any grade ICANS [HR 2.46 (1.43-4.23) p=0.001], and ICANS grade 3+ [HR 3.38 (1.82-6.26) p=&amp;lt;0.001] were associated with an increased risk of death. On analysis of associations with PFS, lack of response to CART-19 therapy [SD/NR HR 15.05 (3.92-57.74) p=&amp;lt;0.001], any grade ICANS [HR 1.74 (1.06-2.87) p=0.029], and ICANS grade 3+ [HR 2.52 (1.38-4.59) p=0.003] were associated with increased risk for progression. Grade 3+ ICANS was adversely correlated with PFS in CR pts [HR 3.81 (1.22-11.90) p=0.021] and CR + PR pts. Several factors were associated with increased risk for toxicities. Lack of disease control at the time of CART-19 therapy, [OR 3.30 (0.79-13.79) p=0.003], development of ICANS, any grade [OR 4.08 (1.64-10.14) P=0.003] or grade 3+ ICANS [OR 7.71 (1.28-46.27) p=0.025] correlated with the development of any grade CRS. ICANS of any grade [OR 6.92 (1.12-42.79) p=0.037] and ICANS grade 3+ [OR 6.57 (1.50-28.77) p=0.013] correlated with Grade 3+ CRS. Lack of disease control status [OR 4.18 (0.85-20.55) p=0.011], any grade CRS [OR 4.08 (1.64-10.15) p=0.003], and grade 3+ CRS [OR 6.92 (1.03-46.64) p=0.047] were associated with an increased incidence and severity of ICANS. Conclusions: Disease control assessed by functional imaging at the time of CART-19 therapy for r/r DLBCL may be an independent predictor of CART-19 therapy outcomes. In this cohort, adequate disease control prior to CART-19 therapy was associated with improved ORR, PFS and OS. Optimizing disease control prior to cellular therapy may ultimately improve clinical outcomes while mitigating cellular therapy related toxicity.

Factors Associated with Refractoriness or Relapse after Varnimcabtagene Autoleucel (IMN-003A) in Patients with Relapsed Refractory B Cell Malignancies: Phase 2 First-in-India Industry (IMAGINE) Study

Background: Varnimcabtagene autoleucel (IMN-003A) is an anti-CD19 CAR-T cell immunotherapy for patients with relapsed refractory B cell malignancies (RR BCM) in the Phase 2 IMAGINE study. Some patients (pts) do not respond or relapse early after CD19 directed CAR-T cell therapy. This abstract reviews the factors associated with disease relapse to help improve patient outcomes and development of novel strategies. Methods: Patients (pts) aged 3 to 45 years (B-ALL) and ≥ 18 years (B-NHL) with RR BCM were eligible for IMAGINE study if they had measurable disease, as assessed by lymphoid blasts (B-ALL) or metabolic tumour bulk (B-NHL), received ≥1 prior regimen, refractory to the last line of treatment with good performance status (ECOG 0 to 1). Multiple characteristics for disease progression were reviewed (n=36) and risk stratified as: 1) Baseline parameters (age, lines of treatment, bridging therapy, cytogenetics, blasts, total metabolic tumour volume (TMTV), sum of perpendicular diameter (SPD), refractory, relapse within 6 months, laboratory parameters - haemoglobin, neutrophil count, lymphocyte count, platelet count, CRP, LDH, ferritin, baseline interleukin-6 (IL-6), baseline total T cells, CD4, and CD8 subsets in peripheral blood); 2) Apheresis parameters (total T cells, naïve / central memory in CD4 and CD8 subsets); 3) Final Product characteristics [total CAR+ cells, naïve / central memory in CD4 and CD8 subsets, CD8 (naïve &amp; central memory subsets / tumour burden (TMTV and SPD), product doubling time] and 4) Post Infusion factors (CAR peak &amp; persistence, B cell aplasia, hypogammaglobulinema, infections and intravenous immunoglobulin (IVIg) replacement). These parameters were analyzed using chi-square and appropriate multivariant odds ratio (OR) to examine the association with disease relapse. Results: At data cut-off, of 25 pts enrolled (median age 31 yrs, range 3 - 66) with RR BCM (n=13 B-ALL; n=12 B-NHL), 24 pts received var-cel (1 withdrawal). Median follow-up after IMN-003A administration was 205 days (range 12 - 434). Overall response rate (ORR) was 91.7% (22/24) at D+28 (B-ALL 91.7%; B-NHL 91.7%) and 80.9% (17/21) at D+90 (B-ALL 80%; B-NHL 81.8%). Median progression free survival (PFS, range 12-NR), duration of response (DOR, range 0-NR) and overall survival (OS) were not reached (range 12-NR). Treatment related mortality was 4.2% (n=1/24); 3 pts died of disease progression. Nine pts had relapsed disease (B-ALL 4; B-NHL 5; overall 37.5%; CD19+ 7 pts; CD19- 2 pts; B-ALL: CD20 variable; CD22+ n=4/4; B-NHL PDL1 n=1/5) with median PFS of 178 days (range 28-319). For relapsed pts, median duration of B cell aplasia after primary infusion was 270 days (range 70-NR); var-cel was detected in 1 pt (n=1/4) at relapse and hypogammaglobulinema (IgG &amp;lt;4g/L) was seen in 4 pts. For the 36 multiple parameters studied, age, high risk cytogenetics / genomic aberrations, refractoriness / early relapse &amp;lt;6m, blasts burden in B-ALL, absolute lymphocyte count, inflammatory markers (LDH, ferritin) and baseline T cell subsets did not show association with disease relapse. Ten variables showing some association with disease progression on univariant analysis were: SPD, baseline haemoglobin, platelets, CRP, Apheresis CD8+ T N+CM, Final Product doubling time, CAR-T dosage (B-NHL), CD8 CAR+ T N+CM (weight &amp; dose adjusted), Post Infusion Cmax and IVIg replacement. Multivariant analysis of these parameters showed some statistical significance for following variables: Baseline Platelet count &amp;lt;200 x 10 9/L (overall); Final Product doubling time ≥1 day (B-ALL); baseline SPD ≥2000 mm 2, Hb &amp;lt;12 g/dL, Platelet count &amp;lt;200 x 10 9/L and post infusion IVIg replacement (B-NHL), Table1 &amp; Figure 1. Of these variables, statistically significant association was seen with Final Product doubling time ≥1 day (B-ALL) and baseline SPD ≥2000 mm 2 with Hb &amp;lt;12 g/dL and Platelet count &amp;lt;200 x 10 9/L (B-NHL). The impact of IVIg replacement on efficacy needs further study. Conclusions: In the IMAGINE study, with ORR 80.9% at primary endpoint and median PFS not reached, relapse was seen in 37.5% pts with median PFS of 178 days. Multivariant analysis has identified factors which may predict disease relapse. Further research is needed to identify strategies such as reinfusion or CAR-T targeting a different antigen to achieve cure.

Real-World Outcomes in Patients with Transformed Follicular Lymphoma Treated with CD19-Targeting CAR-T Therapy

INTRODUCTION. CD19-targeting CAR-T cell therapy has changed the treatment landscape of refractory/relapsed large B cell lymphoma, including transformed from FL (tFL). Axicabtagene ciloleucel (axi-cel), lisocabtagene maraleucel (liso-cel), and tisagenlecleucel (tisa-cel) are now FDA-approved for the treatment of tFL, but limited data are available on their clinical activity in patients (pts) with tFL since outcomes in those pts were not separately reported in registrational studies. Here, we report a single center's experience with CD19-directed CAR-T cell therapy in pts with tFL. METHODS. We performed a retrospective analysis of 54 pts with tFL treated with CAR-T cell therapy from January 2018 to December 2022. Pathological evidence of histologic transformation (HT) was confirmed. The main clinical-biological characteristics of the pts were extracted from the electronic medical records. Cytokine release syndrome (CRS) and neurotoxicity were graded according to ASTCT guidelines. Progression-free (PFS) and overall survival (OS) were measured from the time of CAR-T cell infusion; PFS events were death, relapse, and disease progression. RESULTS. Within our cohort of patients with tFL, the median age was 67 years (range 42-81), 65% were male and 77% had stage III-IV disease. Eight of the pts (15%) had an ECOG Performance Status (ECOG-PS) ≥2. Median time to transformation was 27 months from original FL diagnosis (range 0 to 223), including 6 cases with composite lymphoma (FL + aggressive histology) and 4 with synchronous transformation. Twenty percent presented with high-grade B-cell lymphoma (HGBCL) with MYC and BCL2 and/or BCL6 rearrangements. Using Hans' algorithm, 85% (44/52) were identified as a germinal center B-cell origin (GCB). In 22 cases, targeted sequencing using the MSK-IMPACT panel was performed at the time of HT or prior to CAR-T. TP53 mutation/deletion was present in 50% of the cases (Figure 1). Pts received a median of 3 (range 1-9) prior lines of therapy including those for FL, and 9 pts (17%) had undergone prior autologous stem cell transplantation (SCT). Thirty-four pts (63%) were refractory to the last therapy, including 29 pts (53.7%) with primary refractory disease after HT. Forty-one pts (76%) received bridging therapy. Seventy-two percent of pts received axi-cel, 19% tisa-cel, and 9% liso-cel. CRS of any grade was seen in 43 (80%) pts with grade &amp;gt;3 in 3 (6%). Neurologic toxicity of any grade was observed in 20 (37%) pts with grade &amp;gt;3 in 7 (13%). The median duration of follow-up was 26.2 months. The overall response rate was 87%, including 67% complete response (CR). The median response duration (DOR) was 11 months, with a 2-year DOR of 42% (95% CI: 28-61%). Objective responses were achieved in pts with high-risk features such as HGBCL, TP53 mutation, and chemotherapy-refractory disease. Twenty-nine pts experienced relapse/progression during follow-up, with a median PFS for the entire cohort of 9.8 months and a 2-year PFS of 40% (95% CI: 28.3-56.3%) (Figure 2). Refractory disease after HT and high LDH serum levels were associated with a significantly lower PFS (median PFS not reached vs. 6.4 months, P=0.031; 24.4 vs. 3.2 months, P=0.003 respectively). Notably, all pts who achieved PR eventually progressed. In 23 pts with relapse, a biopsy was obtained, showing DLBCL or HGBCL morphology in all instances. Interestingly, all relapses occurred during the first 24 months. Twenty-six pts received salvage therapy after CAR-T progression, with a median of 1 line (range 1-7). Out of these, eight (31%) pts achieved a CR and went to allogenic SCT as a consolidative strategy. Twenty-two pts died during follow-up, 19 due to progression and 3 of non-lymphoma causes, including 2 of COVID-19 infection. The median OS was 31 months, and the 2-year OS rate was 57% (95% CI: 44.3-73.8%) (Figure 2). Median OS was not reached among the 36 pts who achieved a complete response. CONCLUSIONS. CD19-targeting CAR-T cell therapy is effective for pts with relapsed/refractory tFL, including patients with characteristics of poor prognosis, with efficacy and toxicity profiles comparable to that observed in previous DLBCL studies. Unfortunately, pts who relapse post-CAR-T therapy have limited effective therapeutic options available, and this currently remains an unmet medical need within the field.

Primary Analysis of Varnimcabtagene Autoleucel (IMN-003A) in Phase 2 Study (IMAGINE), a First-in-India Industry CD19-Directed CAR-T Cell Therapy for Patients with Relapsed Refractory B Cell Malignancies

Background: Varnimcabtagene autoleucel (IMN-003A) is an autologous second-generation CAR-T cell product with a 4-1BB co-stimulatory domain and a non-FMC63 based murine single chain variable fragment targeting CD19 (A3B1 binder), manufactured in India. Preclinical and Phase 1 study was conducted at HCB / IDIBAPS Spain. Here, we present the primary analysis of IMAGINE, a Phase 2, multicenter, single-arm study of var-cel for patients in India with relapsed/refractory B cell malignancies (RR BCM) (CTRI/2022/03/041162). Methods: Patients (pts) aged 3 to 45 years (B-ALL) and ≥ 18 years (B-NHL) with RR BCM were eligible if they had measurable disease, as assessed by lymphoid blasts (B-ALL) or metabolic tumour bulk (B-NHL), received ≥1 prior regimen, refractory to the last line of treatment with good performance status (ECOG 0 to 1). Bridging therapy was allowed after apheresis. Cyclophosphamide (300 mg/m 2) and fludarabine (30 mg/m 2) on days -5 to -3 were used as preparative lymphodepletion regimen. The target dose was 1x10 6/kg CAR+ cells (B-ALL) and 5x10 6/kg CAR+ cells (B-NHL) (overall range 0.1x10 6 to 5x10 6) and was administered in a fractionated manner (10%/30%/60%) over 3 days with at least 24h between infusions. Primary objectives were overall response rate (ORR: CR + CRi in B-ALL and CR + PR in B-NHL) at day +90 after first infusion, and safety. Response was assessed as per NCCN (B-ALL) and IWG (B-NHL) criteria; bone marrow minimal residual disease (MRD) for B-ALL was analyzed by flow cytometry at 10 -4 sensitivity and PET-CT for B-NHL. Adverse events (AEs) were graded using CTCAE v5.0. CRS and ICANS were graded according to the American Society for Transplantation and Cellular Therapy (ASTCT) criteria. Results: At data cut-off, of 25 pts enrolled (median age 31 yrs, range 3 - 66) with RR BCM [n=13 B-ALL, median blasts 0.34% (range 0.01 - 27.2); n=12 B-NHL, median TMTV 67.9 ml (range 27.1 - 1177), median SPD 3846 mm 2 (range 1001 to 35849], 24 pts received var-cel (1 withdrawal) with majority of infusions on Days 0, +3, +7 and 12 pts (50%) needed bridging therapy. Median CAR-T cell manufacturing time was 14 days (range 10 - 27) with 100% manufacturing success. Median follow-up after IMN-003A administration was 205 days (range 12 - 434). Overall response rate (ORR) was 91.7% (22/24) at D+28 (B-ALL 91.7%, MRD neg 83.3% (n=10/12); B-NHL 91.7%, CR 66.7%) and 80.9% (17/21) at D+90 [B-ALL 80%, MRD neg 80% (n=8/10); B-NHL 81.8% (9/11), CR 63.6%]. One B-NHL pt in PR at D+28 achieved CR at D+90. Three pts relapsed by D+90. Of MRD evaluable pts, response was 100% at day+28 (n=11/11) and 88.9% at D+90 (n=8/9). Median time to first response was 28 days. Median progression free survival (PFS, range 12-NR), duration of response (DOR, range 0-NR) and overall survival (OS) were not reached (range 12-NR). AESIs reported were CRS (Grade [G] 1 62.5%; G3+ 4.2%; overall 66.7%); ICANS (G1 4.2%; G3+ 0%; overall 4.2%); neutropenia (G3+ 91.7%; overall 100%); anemia (G3+ 29.2%; overall 95.8%); and thrombocytopenia (G3+ 20.8%; overall 91.7%). CRS median onset was D+5 and duration 3 days. No G3+ ICANS was reported. Tocilizumab, steroids and anakinra usage was in 37.5% (n=9/24, majority for persistent G1 CRS), 8.3% and 4.2% respectively. Treatment related mortality was 4.2% (n=1/24); 3 pts died of disease progression. IMN-003A cells demonstrated peak expansion on D+10 (range 7 - 28 days). 79.2% at D+28 and 29.2% at D+90 had measurable CAR+ T cells in peripheral blood; median D+28 (range D+10 - NR). Updated results will be presented in the meeting. Conclusions: Varnimcabtagene autoleucel (IMN-003A), a First-In-India Industry CD19-directed CAR-T Cell Therapy for RR BCM, has demonstrated manageable safety profile and durable efficacy outcomes with deep responses including absence of severe neurotoxicity. This offers a significant benefit over standard treatment options for patients with RR BCM.

2721. Respiratory Virus Infections Following CAR T-cell Therapy: Risk Factors and Outcomes

Abstract Background Chimeric antigen receptor (CAR) T-cell therapy is a novel cancer therapy which functions by engineering patients’ own cells to target a malignancy. The preparative lymphodepleting chemotherapy and cell versus tumor effect create a novel, dynamic state of immunocompromise. Respiratory viruses have been found to be the predominant late infectious complication, but little is known about specific risk factors and outcomes of these infections. Methods We retrospectively identified adult patients who received CD19-directed CAR T-cell therapy at our center and followed them up to two years post-infusion (or until disease progression, death, or February 2022 — whichever came first). We undertook structured chart review using REDCap. Descriptive statistics were used where indicated. An adapted ordinal scale was used to assess the severity of respiratory virus infections (RVIs) (PMCID: PMC9278199). Results We found 73 patients who met search criteria. Of those, 23 patients (32%) developed an RVI, and their baseline characteristics are listed in Table 1. There were 38 episodes of RVI with an average of 1.65 episodes per affected patient. The median time from infusion to RVI was 180 days. The etiologic agent for the majority of RVIs was either unknown or rhino/enterovirus (Figure 1). The median ordinal score for RVI severity was 1, corresponding to ambulatory management for most (Figure 2). However, 24% of patients required a higher level of care. In patients where serial NAATs were performed, the duration of viral shedding was a median of 33 days (IQR 32 – 39). Immediately prior to infection the median IgG was 370 mg/dl (IQR 292 – 566), ANC was 1690 cells/μL (IQR 873 – 3165), and ALC was 480 cells/μL (IQR 285 – 703). 10 (43%) patients were treated with IVIG and 4 (17%) patients received antivirals. Many patients did not seek care for their RVIs or sought care outside of the Hematology/Oncology clinic. The RVI diagnosis relied on the impression of the treating physician at the time the patient presented with symptoms, or when the patient described past symptoms for which they did not present to the Hematology/Oncology clinic for care. Additionally, sometimes a full panel of respiratory viral nucleic acid amplification testing was done and negative (possibly false negative due to a collection issue or non-tested virus). Other times only COVID/FLU/RSV testing was done. Other times no respiratory virus panel was done. “Unknown” is a clinical syndrome of respiratory viral infection encompassing patients either without nucleic acid amplification testing being performed or with negative testing. The Ordinal Scale for EHR Use* was used to rank the severity of each instance of RVI. Possible rankings included 1, 3, 5, 7, 9, or 11. None of the RVIs met the criteria for 9 (organ support) or 11 (death). *Khodaverdi M, Price BS, Porterfield JZ, Bunnell HT, Vest MT, Anzalone AJ, Harper J, Kimble WD, Moradi H, Hendricks B, Santangelo SL, Hodder SL; N3C Consortium Collaborators. An ordinal severity scale for COVID-19 retrospective studies using Electronic Health Record data. JAMIA Open. 2022 Jul 9;5(3):ooac066. doi: 10.1093/jamiaopen/ooac066. PMID: 35911666; PMCID: PMC9278199. Conclusion There is a high burden of delayed RVI in patients who receive CAR T-cell therapy, and these infections can lead to severe illness requiring hospitalization. Clearance of virus was delayed, with duration of shedding lasting at least one month for most. Many CAR T-cell therapy patients had lower immunoglobulin G and lymphocyte counts prior to RVI. Further research is needed to understand the best treatment and prevention strategies for RVIs in this population. Disclosures All Authors: No reported disclosures

CAR-T Cell Therapy in Patients with Refractory Systemic Autoimmune Diseases Exhibits Less Inflammation, Toxicities and Different Cellular Dynamics Compared to Patients with B Cell Lymphoma

Chimeric antigen receptor (CAR) T-cell therapies have shown high efficacy in the treatment of B cell non-Hodgkin lymphoma (NHL) and acute lymphoblastic leukemia (ALL) and are established as a standard treatment for patients with hematological malignancies. Aside from malignant B cells, autoreactive B cells can also cause great harm in patients with autoimmune diseases (AID), resulting in chronic inflammation, organ damage, and increased mortality. We have recently demonstrated that CD19-directed CAR-T cell therapy is feasible and effective in patients with refractory systemic lupus erythematosus (Mougiakakos et al, 2021; Mackensen et al., 2022), antisynthetase syndrome (Müller et al., 2023) and systemic sclerosis (Bergmann et al., 2023). Despite these promising data, there are many uncertainties in the treatment of AID patients with cellular therapies, which were primarily developed for the treatment of cancer patients. Here, we analyzed the occurrence and severity of toxicities, inflammatory markers, and the cellular dynamics of 15 AID patients and 40 NHL patients undergoing CAR-T cell therapy. All patients were treated in our center with either commercial CAR-T cell products (Axicabtagenee ciloleucel, Tisagenlecleucel, Lisocabtagen maraleucel) or with the investigational medicinal product MB-CART19.1 (in-house manufactured 2 nd generation anti-CD19 CAR-T cells with a 4.1BB co-stimulatory domain; Kretschmann et al., 2023). Average peak expansion was reached at day 7 in both patient groups. Despite comparable average peak levels, patients with AID showed lower incidence and severity of cytokine-release syndrome (CRS) and immune-effector cell associated neurotoxicity syndrome (ICANS) compared to the NHL cohort. Consistent with reduced toxicity, AID patients received less tocilizumab and glucocorticoid treatment. Bone marrow toxicity with severe and/or prolonged cytopenia is a frequent long-term CAR-T cell related adverse event. Of interest, AID patients demonstrated a less profound decrease of neutrophils, platelet counts, and hemoglobin after CAR-T cell therapy compared to NHL patients and a faster recovery to normal values. Occurrence and duration of severe neutropenia (&amp;lt;500 neutrophils/µl) also differed between both patient cohorts. There was no late bone marrow toxicity in AID patients, whereas 19 of 40 patients with NHL showed at least one &amp;gt; grade 3 blood count reduction. In line with the Hematotox-Score predicting bone marrow toxicity, baseline inflammation (e.g. C-reactive protein, ferritin) prior to CAR-T cell treatment was higher in lymphoma patients than in AID patients. While AID patients quickly returned to normal ferritin values, elevated ferritin levels often persisted in the NHL cohort after CAR-T cell therapy. Given that AID patients showed fewer late toxicity and lower long-term inflammation, we speculated that persistence of CAR-T cells was lower. In line, longitudinal monitoring of the patient's immune cells including CAR-T cell kinetics demonstrated a typical contraction of CAR-T cell numbers with low-level persistence in both cohorts. We did not observe a difference in absolute CAR-T cell numbers or dynamics within the first three months after treatment. In contrast to NHL patients in remission, AID patients did not develop long-term persistence of CAR-T cells as most patients lost CAR-T cells within 1 year after cell infusion. Consistent with this observation, all AID patients showed B-cell reconstitution after loss of CAR-T cell persistence. Taken together, we observed less toxicities and severe adverse events in AID patients than in NHL patients despite similar CAR-T cell expansion and dynamics. The lack of CAR-T cell persistence and the early recurrence of B cells in AID patients is so far not explained and could provide novel insights in the biological processes controlling long-term CAR-T cell persistence.

Moving CAR-Ts to the outpatient clinic.

As centres obtain more experience with commercial CARs, there has been increasing interest in trying to move as much as the procedure as possible to the outpatient clinic to reduce costs, maximize reimbursement and increase patient satisfaction. The report by Ly et al. details how their centre implemented outpatient CAR therapy and were able to reduce admission time without affecting outcomes. Commentary on: Ly et al. Outpatient CD19-directed CAR T-cell therapy is feasible in patients of all ages. Br J Haematol 2023;203:688-692.

Bone marrow fibrosis is associated with non-response to CD19 CAR T-cell therapy in B-acute lymphoblastic leukemia.

CD19 directed CAR T-cell therapy is used to treat relapsed/refractory B-cell acute lymphoblastic leukemia. The role of the pre-CAR bone marrow (BM) stromal microenvironment in determining response to CAR T-cell therapy has been understudied. We performed whole transcriptome analysis, reticulin fibrosis assessment and CD3 T-cell infiltration on BM core biopsies from pre- and post-CAR timepoints for 61 patients, as well as on a cohort of 54 primary B-ALL samples. Pathways of fibrosis, extracellular matrix development, and associated transcription factors AP1 and TGF-β3, were enriched and upregulated in nonresponders (NR) even prior to CAR T cell therapy. NR showed significantly higher levels of BM fibrosis compared to complete responders by both clinical reticulin assessment and AI-assisted digital image scoring. CD3+ T cells showed a trend toward lower infiltration in NR. NR had significantly higher levels of pre-CAR fibrosis compared to primary B-ALL. High levels of fibrosis were associated with lower overall survival after CAR T-cell therapy. In conclusion, BM fibrosis is a novel mechanism mediating nonresponse to CD19-directed CAR T-cell therapy in B-ALL. A widely used clinically assay for quantitating myelofibrosis can be repurposed to determine patients at high risk of non-response. Genes and pathways associated with BM fibrosis are a potential target to improve response.

Infectious complications of car T-cell therapy: A longitudinal risk model.

CAR T-cell therapy, where a patient's own T cells are re-engineered to express a receptor to a target of interest, is becoming an increasingly utilized cancer-directed therapy. There are significant toxicities that contribute to a novel state of immunocompromise, leading to new patterns of infectious complications that require further detailed study. We created a single-center cohort of adult recipients of CD19-directed CAR T-cell therapy and assessed infectious outcomes, supportive care received, toxicities, and markers of immune function up to 2 years following CAR T-cell therapy. Descriptive statistics were used as appropriate for analysis. We additionally conducted time-to-event analysis assessing time-to-first infection with either log-rank testing or Cox regression with univariate analysis, before including significant predictors into a multivariate Cox model of time to infection. We identified 73 patients who received CD19-directed CAR T-cell therapy who predominantly had diffuse large B-cell lymphoma. Within 30 days of cell infusion, bacterial and Candida infections were the most common, with 64% of infections due to these organisms. Between 30 days and 2 years postinfusion, respiratory viruses and pneumonia were the most frequent infections, with 68% of infections due to these etiologies. Receipt of tocilizumab, development of immune effector cell-associated neurotoxicity syndrome (ICANS), or lower neutrophil count were associated with quicker onset of infection in a multivariate Cox model. Respiratory viruses remain an important infectious complication of CAR T-cell therapy following the first year. The model may be a useful tool to identify patients at the highest risk of infection.

Inflammatory reactions mimic residual or recurrent lymphoma on [18F]FDG-PET/CT after CD19-directed CAR T-cell therapy

Inflammatory reactions mimic residual or recurrent lymphoma on [18F]FDG-PET/CT after CD19-directed CAR T-cell therapy

The Dutch CAR-T Tumorboard Experience: Population-Based Real-World Data on Patients with Relapsed or Refractory Large B-Cell Lymphoma Referred for CD19-Directed CAR T-Cell Therapy in The Netherlands.

The real-world results of chimeric antigen receptor T-cell (CAR-T) therapy for patients with relapsed/refractory (R/R) large B-cell lymphoma (LBCL) substantially differ across countries. In the Netherlands, the CAR-T tumorboard facilitates a unique nationwide infrastructure for referral, eligibility assessment and data collection. The aim of this study was to evaluate real-world outcomes of axicabtagene ciloleucel (axi-cel) in the Dutch population, including the thus-far underreported effects on health-related quality of life (HR-QoL). All patients with R/R LBCL after ≥2 lines of systemic therapy referred for axi-cel treatment between May 2020-May 2022 were included (N = 250). Of the 160 apheresed patients, 145 patients received an axi-cel infusion. The main reason for ineligibility was rapidly progressive disease. The outcomes are better or at least comparable to other studies (best overall response rate: 84% (complete response: 66%); 12-month progression-free-survival rate and overall survival rate: 48% and 62%, respectively). The 12-month NRM was 5%, mainly caused by infections. Clinically meaningful improvement in several HR-QoL domains was observed from Month 9 onwards. Expert-directed patient selection can support effective and sustainable application of CAR-T treatment. Matched comparisons between cohorts will help to understand the differences in outcomes across countries and select best practices. Despite the favorable results, for a considerable proportion of patients with R/R LBCL there still is an unmet medical need.

Real-world use of tisagenlecleucel in children and young adults with relapsed or refractory B-cell lymphomas.

10031 Background: Survival for pediatric B-cell lymphomas (BCL) exceeds 90% with modern regimens, however outcomes remain poor for patients with relapsed or refractory (R/R) disease. Tisagenlecleucel is a CD19-directed CAR T-cell therapy (CART) that is FDA approved for adults with R/R BCL. No data exists for use of tisagenlecleucel in R/R pediatric BCL. Methods: We surveyed 48 sites in the Pediatric Real-World CAR Consortium to retrospectively describe use and outcomes of tisagenlecleucel for pediatric patients with R/R BCL. This cohort included 10 patients from 7 centers aged ≤25 years who were infused between 2019-2022 and were ≥3 months from CART. We aimed to describe response rates, as determined by each institution based on positron emission tomography, bone marrow evaluation, and/or cerebrospinal fluid (CSF) studies, along with toxicity and outcomes in this population. Results: Ten patients received CART with a median age at infusion of 19 (range, 7-24) years. Five patients had B-lymphoblastic lymphoma (B-LLy), 2 had primary mediastinal BCL, and 1 each had Burkitt lymphoma, diffuse large B-cell lymphoma (DLBCL), and post-transplant lymphoproliferative disorder related DLBCL. Five patients had primary refractory disease, and 5 were in ≥2nd relapse. Three had received prior hematopoietic stem cell transplant (HSCT). Two had CSF involvement, and 1 had central nervous system parenchymal disease at time of infusion. CART was well tolerated with 1 patient experiencing grade 3 cytokine release syndrome and 2 patients experiencing neurotoxicity (grade 2 n = 1, grade 3 n = 1), both of whom had CSF involvement at time of CART infusion. Best overall response was complete response (CR) for 6, partial response (PR) for 2, and refractory disease for 2. Two patients, both with B-LLy, underwent allogeneic HSCT while in CART-mediated CR with B-cell aplasia. Both patients with PR (1 DLBCL, 1 Burkitt) subsequently relapsed with CD19-negative disease; the patient with DLBCL subsequently achieved CR with salvage immuno-chemotherapy and HSCT. All 6 CR patients remain in remission at a median time to follow-up of 31 (range, 14-47) months. Conclusions: This multicenter case series of CD19-directed CART for R/R pediatric BCL suggests that tisagenlecleucel may be safe and active in this population with all CR patients currently in sustained remission. Larger studies are needed to understand how best to incorporate CART into treatment for R/R pediatric BCL. [Table: see text]