Post CAR-T Research Articles

Immune Reconstitution Post CAR-T - A Role for the Immunologist in Unlocking the CAR-Key?

CAR-T cell therapy utilizes a synthetic chimeric antigen receptor on T-cells to target CD19+ B-cell lineage neoplasms. A critical arm of post CAR-T cell therapy is monitoring for immune reconstitution. We hypothesized that laboratory and clinical immunologic evaluation are underutilized after CAR-T cell therapy.

A potential role of preexisting inflammation in the development of acute myelopathy following CAR T-cell therapy for diffuse large B-cell lymphoma

The event of anti-CD19 chimeric antigen receptor (CAR)-T therapy inducing serious neurotoxicity in patients with diffuse large B-cell lymphoma (DLBCL) is recognized; however, the patterns of symptoms and severity vary greatly from patient to patient. We report an exceptional presentation of acute myelopathy in a refractory DLBCL following successful CAR-T treatment along with grade 3 cytokine release syndrome (CRS) and neurotoxicity. The patient was initiated on high-dose methylprednisolone (MPS) resulting in rapid improvement of neurological symptoms. Yet the myelopathy patient (MP) experienced severe lower limb motor deficit, and a subsequent spinal cord MRI revealed myelopathy with a sensory level at segment T2. Multimodal therapy consisting of MPS, intravenous immunoglobulin and anakinra therapy resulted in complete reversal of myelopathy condition and the patient remained cancer free. The assessment of time trends of serum cytokines at baseline and post CAR-T infusion in MP compared to other 4 DLBCL complete responder patients with varying degree of CRS following CAR-T infusion, suggested pre-existing baseline inflammatory conditions in MP with altered levels of cytokines. These findings, if corroborated by similar case studies, have the potential to generate novel insights into the manifestation of myelopathy following CAR-T therapy and the successful clinical management of such complications.

1163. HIV-1 NAAT Pitfalls in B-cell Lymphoblastic Leukemia Patients Following CAR-T Cell Therapy

BackgroundCAR-T Cell Therapy is approved for the treatment of pediatric patients with relapsed/refractory B-ALL. Lentiviral vector technology, highly modified from HIV-1, is used to induce stable, long-term transgene expression by integration into the host genome. This integration may interfere with HIV-1 NAAT producing false-positive results. MethodsA retrospective chart review of Pre-B ALL patients who underwent to CAR T cell therapy with KYMRIAH(tisagenlecleucel) at a single institution between January 2019 and May 2021 to assess for patients whose CAR-T infusion interfered with post-infusion HIV-1 testing. All patients had HIV NAAT pre and post CAR T-cell therapy (using platform, Roche COBAS AmpliPrep/Quantitative TaqMan HIV-1 T). Reactive HIV NAAT by Roche test were subsequently tested using different HIV-1 assay platforms to rule out or confirm HIV infection.ResultsWe report three cases in which interpretation of HIV-1 NAAT testing was complicated by CAR T cell therapy. Case 1: 1-year-old male with refractory infantile leukemia was found to have a reactive HIV NAAT post CAR-T in routine infectious screening prior to SCT. Case 2: 3-year-old refractory ALL planned for SCT who had a reactive HIV NAAT 9 months post CART. Fourth-generation HIV-1 testing (targeting the p24 antigen and anti-HIV-1 antibodies) was negative pre and post CART. Viral loads were also undetectable indicating false-positive post-CAR-T HIV-1 NAT test results. Case 3: 21-year-old sexually active female with relapsed B cell ALL. Post CAR-T HIV NAAT was reactive, and a quantitative viral load was positive at 176 copies/mm3 one day prior to start of stem cell transplant conditioning regimen. Aptima HIV testing is typically used as confirmatory test for CAR-T associated false positive HIV NAT cases, but surprisingly, the Aptima test was also reactive. Additional testing with Abbott m2000 Realtime HIV-1 assay and 4th generation p24 antigen-based testing were both negative. Table 1 Summary of reported patients with false-positive HIV-1 NAAT test results following CAR T cell therapy and Table 2, HIV platforms used for screening and diagnosis with interpretations following CAR T cell therapy.ConclusionClinicians need to be aware of potential false-positive HIV testing after CAR-T therapy. HIV testing platforms with targets not used in lentiviral vectors (4th generation test/P24, or Abbott test/integrase region) are highly recommended to avoid delays in subsequent therapy and unwanted stress for the patients, families, and cliniciansDisclosures All Authors: No reported disclosures

NCMP-11. SPINAL CORD INFARCT AFTER CAR-T TREATMENT

Abstract Cortical and subcortical neurotoxicity from CAR-T therapy is a well described complication in literature, with over 40% of patients experiencing at least one neurologic side effect. However, spinal cord toxicity from CAR-T therapy is less well described. To our knowledge, this is the first reported case of a spinal cord infarct following CAR-T therapy. A 44 year old male with primary refractory DLBCL without CNS involvement, which was refractory to R-CHOP, R-ICE, and hyperCVAD part B underwent CD-19 CAR-T treatment. The day after infusion he developed grade 1 cytokine release syndrome (CRS) with fever and up trending inflammatory markers. Infectious work up was negative and he was treated with tocilizumab and dexamethasone. His fever resolved and markers down trended. On day 5 post CAR-T, he became encephalopathic, developed severe back pain, and was unable to move his bilateral lower extremities. He was treated with 2nd and 3rd doses of tocilizumab, dexamethasone and was started on anakinra. Patient’s mental status cleared by day 7 and he was found to have a dermatome sensory level at T10 with flaccid bilateral lower extremity paralysis. MRI Brain was unremarkable, but a spinal MRI showed longitudinally extensive cord edema and diffusion restriction at T10. Due to an initial question of transverse myelitis, he was treated with a 3-day course of IV methylprednisolone, with no improvement in symptoms. CSF studies were unable to be obtained due to his thrombocytopenia. Repeat MRI obtained 10 days after initial imaging showed resolution of cord edema, but continued areas of FLAIR hyperintensity at T10 through the conus. Despite aggressive rehabilitation services, four months later, patient remained paralyzed in his lower extremities with an indwelling foley catheter. He remains in a complete remission.

Triple MAPK Inhibition Salvaged a Relapsed Post BCMA CAR-T Cell Therapy in Multiple Myeloma Patient with BRAF V600E Dominant Clone

Background:Multiple Myeloma (MM) is a progressive plasma cell neoplasm characterized by heterogeneous clonal expansion. Despite numerous targeted therapy options, failing anti-BCMA CAR-T cell therapy represents a challenging treatment course with dismal prognosis. 53% of relapsed/refractory (rr) MM patients have shown emerging clones harboring mutations within the MAPK signaling pathway including the targetable BRAF V600E in 7% of cases. Allosteric kinase inhibition of MAPK pathway with BRAF monomer selective inhibitors +/- MEK inhibitor have been frequently attempted with rrMM patients with equivocal outcome on both disease progression and survival. This could be ascribed to the feedback activation of the pathway via BRAF dimers induction. In solid tumor contexts, a recent study has revealed that the multi-kinase inhibitor regorafenib is a potent and selective inhibitor of dimeric BRAF. Moreover, the study demonstrated overcoming of this negative feedback by combining two inhibitors targeting BRAF in its monomeric and its dimeric form, respectively, with MEK inhibition leading to more efficacious and tolerable treatment (Adamopoulos C. et al. Cancer Discov. 2021). Here, we show the applicability, effectiveness, and tolerability of the aforementioned triple therapy strategy in hematological malignancy context to salvage post BCMA CAR-T cell therapy in a BRAF V600E rrMM patient.Material and Methods:CD138 + selected cells were collected from bone marrow (BM) and patient's plasmacytoma before and after CAR-T cell therapy relapse, respectively. Samples were processed using the standard GATK 4 workflows and a consensus mutation calling approach was used to call somatic mutations using a matched normal obtained from peripheral blood. PhyloWGS (Deshwar et al, Genome Biol 2015) was then used to perform intra-tumor heterogeneity modeling and phylogeny estimation.CD138 + selected cells from BM of rrMM patient were treated with encorafenib (50nM) and binimetinib (250 nM) +/- regorafinib (1mM) for 48 hours, cells were harvested, lysed and immunoblotted with BRAF V600E and pERK antibodies.In parallel, rrMM patient BM selected CD138 + cells' sensitivity to MAPK inhibitors were assessed by Travera. Cells are incubated with different inhibitors at varying concentrations and combinations for 15 hours before having their single-cell mass distributions measured. Sensitivity is then characterized by the relative statistical difference (Hellinger distance) between conditions and untreated controls.A rrMM patient was started on targeted triple therapy using the following combination: BRAF monomer-inhibitor, dabrafenib (100mg, orally twice daily), a MEK-inhibitor, trametinib (1.5mg, orally for 21/28 days daily), and a BRAF dimer inhibitor, regorafenib (40mg, orally once daily).Results:Whole Exome Sequencing (WES) showed a BRAF V600E mutation was present prior to CAR-T cell therapy and persisted through subsequent treatments. The variant allele frequency of the mutation was 41% post CAR-T cell therapy (Figure 1A).Western blot of CD138 + cells confirmed BRAF V600E mutation with a specific antibody, and showed ERK phosphorylation, which was inhibited with trametinib. Longer exposure to trametinib confirmed a feedback loop activating MAPK which was abrogated with the BRAF dimer inhibitor regorafenib (Figure 1B).Travera analysis showed CD138 + cells' sensitivity to the combination of trametinib at 5mM, and dabrafenib at 1µM. Adding regorafenib at 1µM could slightly improve the response compared to the double combination. (Figure 1C).Clinically, three months of the triple therapy administration has led to prompt reduction in subcutaneous skin lesions as well as 80% reduction in free lambda chain (Figure 1D). Furthermore, the patient exhibited good tolerance to all three medications with minimal side effects (grade 1 fatigue). The treatment regimen allowed the patient to carry out activities of daily living and resume work.Conclusion:We have shown the applicability, effectiveness, and tolerability of the triple MAPK inhibition in a hematological malignancy context to salvage post BCMA CAR-T cell therapy in a rrMM patient with BRAF V600E mutation. Also, we have revealed the power of routine WES in tracking clonal evolution, and identifying targetable mutations which allows tailoring of therapeutics for MM patients. [Display omitted] DisclosuresStevens: Travera: Current Employment. Parekh: Foundation Medicine Inc: Consultancy; Amgen: Research Funding; PFIZER: Research Funding; CELGENE: Research Funding; Karyopharm Inv: Research Funding.

Clinical Outcome of Refractory Lymphoma Patients with Non Response to Chimeric Antigen Receptor T Cell Therapy

BackgroundChimeric antigen receptor T cell (CART) therapy has remarkably improved the outcome of patients (pts) with relapsed refractory B cell non-Hodgkin lymphoma. Anti-CD19 directed CART therapy have shown to yield durable remission in 40%-50% of patients with relapsed refractory (r/r) diffuse large B cell lymphoma (Neelapu et al. NEJM 2017; NCT 02348216). However, pts who had disease progression post CART therapy (non-responders) have poor outcomes. There is paucity of information regarding negative predictors for disease progression and outcome of non-responders post CART therapy.MethodsWe conducted a single center retrospective study of 11 patients with relapsed refractory large B cell lymphoma who underwent treatment with CART in our institution from December 2019 to June 2021 and further studied the baseline characteristics, and clinical outcome of 8 pts who were non responders to CART therapy.ResultsAll patients received low dose fludarabine cyclophosphamide based lymphodepleting conditioning regimen followed by anti-CD19 directed CART cells using CD28 as costimulatory domain with a target dose of 2 x 10 6 cells /kilogram of body weight.Baseline characteristics as shown in [Table 1]. Median age at CART therapy was 61 years (range 49-71). Median ECOG score at CART therapy was 1. All patients had chemo refractory disease at time of CART therapy with 9 patients having refractory diffuse large B cell lymphoma and 2 patients had transformed large B cell lymphoma. Genomic studies showed high risk disease in 4 patients with double hit lymphoma, 3 patients with complex cytogenetics with one having 17 p deletion and 2 patients with double expressors of c-myc and bcl2. Only 5 patients had available Ki-67 score > 80%. All patients had stage III-IV disease at the time of CART therapy. Seven pts had extra nodal disease and one patient had CNS involvement. Median R-IPI score at time of CART therapy was 3 (range 2-4). Median LDH, serum ferritin and serum CRP at the time of CART therapy was 388 (range 136-1489); 831 (range 116.9-1503); and 28.1 (range 7.4-226) respectively. Median number of prior therapies were 3 (range 2-9). One patient had prior autologous stem cell transplant. Median absolute lymphocyte count (ALC) and platelet count at CART therapy was 0.01/ul (range 0.01-2.5) and 89 x 10 3/ul (range 10-385) respectively. Median time from last salvage chemotherapy to CART therapy was 62 days (range 28-492).Total six pts had cytokine release syndrome (CRS) with median time for CRS onset was 3.5 days (range 1-8) with all of them having grade 1-2 CRS. Total seven pts had neurotoxicity with median time for onset was 5 days (range 1-41) post CART with 4 pts having > grade 3 immune effector cell associated neurotoxicity syndrome (ICANS). Overall, six and seven pts received tociluzumab and steroids respectively for treatment of CART related CRS and ICANS. Day 30 PET/CT scan showed three responders (2CR,1PR) and eight non responder patients with disease progression.Non responder pts to CART, when compared with responders had higher value of median LDH (438 vs 300; p = 0.92); median CRP (29 vs 13; p = 0.497) ; higher extra nodal involvement ( 6 pts vs one), median R-IPI score at the time of CART ( 4 vs 3), median number of prior therapies (4 vs 3), and median time from last salvage therapy to CART ( 73 days vs 50 days ; p = 0.91). No difference in baseline ALC count and platelet count was noted between the two groups. Compared to responders, non-responder pts had lower incidence of CRS (100% vs 37.5%) and ICANS (100% vs 50%). Post CART therapy, non-responder pts were treated with Nivolumab based immunotherapy in 5 pts, Ipilimumab based therapy in 1 pt, Selinexor in 1 patient and Polatuzumab based therapy in 2 pts.Median progression free survival and overall survival of non-responders was only 30.5 days and 94 days respectively. 5 out of 8 non responder pts died (4 due to disease progression and 1 due to sepsis). All three responder pts were alive and disease free at the end of study. Median follow up of our study was 108 days (range 32- 561).ConclusionsDespite smaller sample size, our study showed dismal outcome of pts who don't respond to CART therapy, showing an unmet need for better salvage therapies in such pts. Refractory lymphoma pts with extra nodal disease involvement, higher LDH and CRP at the time of CART therapy could be negative predictors for response. Further prospective studies with larger sample size required to further validate these findings. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Outcomes with Chimeric Antigen Receptor T-Cell Therapy in Relapsed or Refractory Acute Myeloid Leukemia: A Systematic Review and Meta-Analysis

Background:Acute myeloid leukemia (AML) is a clonal hematologic malignancy that generally affects older adults. Despite achieving complete remission (CR) in over two-third of patients with initial induction therapy and subsequent allogeneic hematopoietic stem cell transplantation in intermediate-high risk patients, more than half of AML patients experience disease relapse. The prognosis of patients with relapsed/refractory AML (RR-AML) is often poor and treatment modalities are limited. Chimeric antigen receptor T cell (CAR-T) therapy has shown promising results in lymphoid malignancies and myeloma, and these are now being explored for the management of RR-AML. In this systematic review and meta-analysis, we aimed to investigate the outcomes of CAR-T therapy in RR-AML patients.Methods:Following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines, a comprehensive literature search was conducted on three databases (PubMed, Cochrane Register of Controlled Trials, and Clinical trials.gov) using MeSH terms and keywords for “Leukemia, Myeloid, Acute” AND “Receptors, Chimeric Antigen” OR “adoptive immunotherapy” from the date of inception to April 2021. A total of 673 articles were screened and original studies reporting patients with RR-AML having CAR-T therapy as the only intervention were included while reviews, duplicate, and non-relevant articles were excluded. A total of 10 studies (8 clinical trials and 2 case reports) were included. The data for following outcomes were extracted: complete response (CR), partial response (PR), overall response rate (ORR), overall survival (OS), progression-free survival (PFS), stable disease (SD), progressive disease (PD), cytokine release syndrome (CRS) and neurotoxicity (NT). Quality evaluation was done using the NIH quality assessment tool. Inter-study variance was calculated using the Der Simonian-Laird Estimator. Proportions along with 95% confidence Interval (CI) were extracted to compute pooled analysis using the ‘meta’ package by Schwarzer et al. in the R programming language (version 4.16-2).Results:We identified 39 patients in 10 studies who received CAR-T therapy for RR-AML. Median age of patients was 35 (7.3-80) years and 59% (n=23) were male. The median follow-up time was 5 (0.7-23) months. (Table 1) Four patients had history of allogeneic hematopoietic stem cell transplant (HCT) prior to CAR-T therapy while subsequent HCT was performed in 5 patients. The pooled analysis showed a CR and ORR of 38.5% (95% CI 0.03-0.81, I 2 =66%, n=29) and 56% (CI 0.18-0.91, I 2=58%, n=29), respectively. Median duration of response was 5.5 (1-23) months. OS was reported from 1.9 months to 23 months. The pooled incidence of CRS and NT were 42.7% (95%CI 0.06-0.87, I 2=66%, n=28) and 1.3% (95% CI 0.00-0.16, I 2= 0%, n=21) respectively. Graft-versus-host disease (GVHD) was reported in 2 patients who had prior and subsequent HCT after CAR-T therapy; first patient developed grade IV GVHD in the setting of salvage therapy with donor lymphocyte infusions for relapsed disease 6 months' post CAR-T and 4 months post second allo-HCT while second patient received CAR-T as part of conditioning therapy and developed grade IV GVHD on day 32.Conclusion:CAR-T therapy has shown favorable results comparable to current salvage therapies for relapsed or refractory AML with an acceptable toxicity profile. However, there are several challenges including the heterogeneous biology of AML, lack of a targetable antigen expression on malignant cells, and immune escape and exhaustion. Future prospective studies with improved CAR-T constructs will hopefully improve the outcomes in this therapeutically challenging patient population. [Display omitted] DisclosuresLin: AbbVie, Aptevo Therapeutics, Astellas Pharma, Bio-Path Holdings, Celgene, Celyad, Genentech-Roche, Gilead Sciences, Incyte, Jazz Pharmaceuticals, Novartis, Ono Pharmaceutical, Pfizer, Prescient Therapeutics, Seattle Genetics, Tolero, Trovagene: Research Funding. Abhyankar: Incyte/Therakos: Consultancy, Research Funding, Speakers Bureau. McGuirk: EcoR1 Capital: Consultancy; Juno Therapeutics: Consultancy, Honoraria, Research Funding; Pluristem Therapeutics: Research Funding; Bellicum Pharmaceuticals: Research Funding; Gamida Cell: Research Funding; Novartis: Research Funding; Astelllas Pharma: Research Funding; Kite/ Gilead: Consultancy, Honoraria, Other: travel accommodations, expense, Kite a Gilead company, Research Funding, Speakers Bureau; Fresenius Biotech: Research Funding; Novartis: Research Funding; Magenta Therapeutics: Consultancy, Honoraria, Research Funding; Allovir: Consultancy, Honoraria, Research Funding.

Cardiovascular Side Effects of Chimeric Antigen Receptor (CAR) T-Cell Products: A Single Center Experience in a Minority Rich, Ethnically Diverse Real-World Cohort

Introduction:Axicabtagene ciloleucel (Axi-Cel), an autologous anti-CD19 chimeric antigen receptor (CAR) T-cell therapy demonstrated efficacy in patients with refractory large B cell lymphoma when conventional treatments failed. Cardiovascular side effects of CAR-T therapy that have been noticed so far include hypotension, left ventricular dysfunction, heart failure and cardiogenic shock in settings of CRS. We aimed to assess the cardiovascular side effects in a racially/ ethnically diverse patient population who underwent CAR-T cell therapy.Methods:This study included thirty-four consecutive adult patients who underwent treatment with CAR-T cell product Axi-Cel at an academic health system between 2018-2021. We performed detailed chart reviews and collected information related to the age, gender, hematological malignancy diagnosis, other medical comorbidities, therapeutic regimens, pretreatment cardiac risk factors, development of CRS with grading , pre and post treatment electrocardiograms ( EKG), transthoracic echocardiograms( TTE) , death, cause of death, and duration between administration of CAR-T products and death of the patients . We collected data pertaining to development of hypotension, EKG changes, arrhythmias, left ventricular systolic dysfunction, heart failure (HF), acute cardiac syndrome (ACS), troponin elevation, echocardiographic changes post CAR-T cell therapy, and follow up visits after 60 days to get information pertaining to development of hypotension, tachycardia or SOB, need for further cardiac work up, and cardiology referral.Results:Mean age of our study participants was 65 years ranging between ages of 30 and 84 years with 38 % (13/34) female and 62% (21/34) male study participants. Study population was predominantly Hispanic, white and African American with percentages of 35% (12/34), 32% (11/34), 26 %(9/34) respectively followed by categories Asian 2.9% (1/34) and other at 2.9 %( 1/34). Sixty seven percent (22/37) patients had primary diffuse large B cell lymphoma (DLBCL) and 32% (11/34) had different primary malignancy with transformation into DLBCL. Thirty eight percent individuals had received autologous stem cell transplant. Sixty one percent (21/34) of our study participants developed cytokine release syndrome, with CRS grades 1-3 in 57% (12/29), 25% (08/21) and 4.7% (1/21) respectively. Thirty four percent (09/34) study participants died after cellular therapy. Septic shock and disease progression each were primary cause of death in 55 % (5/9) of patients, followed by respiratory failure in 22% (2/9) and ventricular fibrillation leading to cardiac arrest in 11% (1/9) of the patients. Mean duration of time between administration of therapy and death was 70 days. The cardiovascular effects noted immediately post CAR-T treatment and observations from follow up oncology visits are listed in Table 1. Troponin elevation was noticed in two study participants in settings of CRS, but one participant exhibited troponin elevation in absence of CRS. Seventeen percent of patients (6/34) developed left ventricular dysfunction after Axi-Cel. Most of them had concurrent CRS but one case of fatal heart failure occurred in absence of CRS. Three patients developed fatal arrhythmias post CAR-T therapy (1- Non sustained ventricular tachycardia in settings of CRS, 2- supraventricular tachycardia in settings of CRS, and 3- ventricular tachycardia needing defibrillation without CRS). Only one patient developed ACS in settings of CRS which lead to patient's demise.Conclusions: In a real world, minority rich cohort, we observed that a significant number of our patients had preexisting cardiovascular findings including abnormal EKG (30% excluding sinus tachycardia) or abnormal echocardiographic findings (46%). Hypotension (68%) and sinus tachycardia (59%) were the most commonly observed cardiovascular toxicities. Although Axi-Cel was in general safe and well tolerated, we observed cardiovascular side effects associated with and independent of CRS. Notably, six patients (17%) developed left ventricular dysfunction including one fatality which was independent of CRS. There was only one fatal coronary syndrome and two cases of troponin elevation in our series. Our study stresses the importance of a thorough cardio-oncology evaluation before proceeding with cellular therapies as well as involved follow up during and after hospitalization. [Display omitted] DisclosuresGritsman: iOnctura: Research Funding. Shastri: Kymera Therapeutics: Research Funding; Onclive: Honoraria; Guidepoint: Consultancy; GLC: Consultancy. Verma: BMS: Research Funding; GSK: Research Funding; Incyte: Research Funding; Medpacto: Research Funding; Curis: Research Funding; Eli Lilly: Research Funding; Stelexis: Consultancy, Current equity holder in publicly-traded company; Novartis: Consultancy; Acceleron: Consultancy; Celgene: Consultancy; Stelexis: Current equity holder in publicly-traded company; Throws Exception: Current equity holder in publicly-traded company.

CAR-T Toxicity Management and Steroid Use in High-Grade B-Cell Lymphoma: Impact on Real-World Survival Outcomes in the UK

CAR-T Toxicity Management and Steroid Use in High-Grade B-Cell Lymphoma: Impact on Real-World Survival Outcomes in the UK

Immunogenicity of Sars-Cov-2 mRNA 1273 Vaccine in Patients with Lymphoid Malignancies

Immunogenicity of Sars-Cov-2 mRNA 1273 Vaccine in Patients with Lymphoid Malignancies

Concurrent Monitoring of Peripheral Blood Circulating Tumor DNA and Circulating Tumor Cells in Relapsed/Refractory Follicular Lymphoma Patients Post Axicabtagene Ciloleucel, a Single Center Experience

Concurrent Monitoring of Peripheral Blood Circulating Tumor DNA and Circulating Tumor Cells in Relapsed/Refractory Follicular Lymphoma Patients Post Axicabtagene Ciloleucel, a Single Center Experience

A Comprehensive Toxicity and Efficacy Analysis of Different Bridging Therapies Prior to Anti CD19-CAR-T Cell Therapy in Patients with DLBCL- a National Multi-Center Cohort Study

Introduction - Data regarding efficacy and toxicity of different bridging strategies prior to CAR-T therapy are scanty. Tisagenlecleucel (Kymriah TM, Novartis) and axictagene ciloleucel (Yescarta TM, Kite/Gilead) were commercially approved for relapsed/refractory (R/R) DLBCL since 2019. We analyzed real-life data of CAR-T therapy among all consecutive patients who were treated in 4 different CAR-T centers in Israel.Methods - From May 2019, 144 R/R DLBCL patients underwent apheresis and continued to receive bridging therapy that included chemo/immunotherapy (n=78, 54%), radiation (n=11, 7.6%), chemoradiation (n=22, 15%), steroids only (n=5, 3.5%) and none (n=28, 19.4%). All patients were evaluated after bridging therapy and prior to CAR-T infusion by PETCT (96%) or CT scan (4%).Results - Median age was 68 (20-88) years and Median follow-up was 13 (4-26) months. All 144 patients underwent successful apheresis. Reasoning for choosing specific bridging therapy was based on low tumor mass (n= 23, 16%), high tumor mass (n=73, 51%), frailty of the patient (n=27, 19%), ongoing significant prior regimen's toxicities (n=14, 10%) and local disease (n=7, 4%). In patients given radiation therapy median dose was 23 (range, 8-30) Gy. In patients given chemo/immunotherapy or chemoradiation, sepsis was the main complications (9% of all patients) during bridging therapy. However, none of the patients had a fatal event. 14 patients (9.7%) did not proceed to CAR-T infusion; 6 (4.2%) had disease progression and died; 8 (5.6%) had manufacture failure). Among the 130 patients that received CAR-T infusion, PET-CT prior to preparative regimen demonstrated CR/PR status in 38%, 50%, 40%, 17%, and 16% of patients given chemotherapy, radiation, chemoradiation, steroids only, or no bridging therapy, respectively (p=.15), Figure 1. Any bridging therapy was associated with a better disease control compared to either steroids only or no treatment (p=.012). There were no differences in the incidences of overall CRS (p=.692), grade 3-4 CRS (p=.196), overall ICANS (p=.941), grade 3-4 ICANS (p=.281), acute kidney disease (p=.244), and liver dysfunction (p=.45) between the 5 different bridging strategies. Cardiovascular complications were more common after chemoradiation (36%), chemotherapy (19%) and radiation (13%), compared with steroids (0%) or no bridging therapy (4%), p=.05. Non-relapse mortality was 0 in all subgroups. PETCT at 1-month post CAR-T infusion demonstrated an increase in CR status percentage across all subgroups with no statistically significant difference in the incidence between the subgroups (p=.27), Figure 1. There was no difference in both progression-free survival (Figure 2) and overall survival between the 5 subgroups (p=.7, and p=.23). Cox regression model identified preinfusion lower ECOG status (HR=0.8, p=.04), preinfusion CR/PR status (HR=.46, p=.037) and 1-month post infusion CR status as a time dependent co-variate (HR=.14, p<.01) to be associated with better progression-free survival, while age and type of bridging therapy did not predict survival.Conclusions - Bridging to CAR-T should be tailored based on patient's and disease's characteristics with the aim to achieve the best disease control prior to CAR-T. However the chosen strategy per-se does not impact long-term outcomes. Intensive bridging therapy is associated with more cardiovascular events after CAR-T infusion. A prospective-controlled-trial allocating patients to different bridging strategies is needed to verify these results. [Display omitted] DisclosuresRam: Gilead: Honoraria; Novartis: Honoraria. Yehudai-Ofir: Novartis: Membership on an entity's Board of Directors or advisory committees; Gilead Sciences: Membership on an entity's Board of Directors or advisory committees. Avivi: Novartis: Speakers Bureau; Kite, a Gilead Company: Speakers Bureau. Zuckerman: Cellect Biotechnology: Honoraria; Gilead Sciences: Honoraria, Speakers Bureau; Novartis: Honoraria; Janssen: Honoraria; BioSight Ltd: Honoraria; Orgenesis Inc.: Honoraria; AbbVie: Honoraria. Yeshurun: Astellas: Consultancy; Janssen: Consultancy. Gurion: Medison; Gilead Sciences; Takeda Pharmaceuticals: Consultancy; JC Health CARE; Roche: Honoraria. Levi: AbbVie: Consultancy, Research Funding.

Anti-CD21 Chimeric Antigen Receptor (CAR)-T Cells for T Cell Acute Lymphoblastic Leukaemia (T-ALL)

CAR-T cell therapy against CD19 has changed the treatment landscape in relapsed/refractory (r/r) B-ALL. R/r T-ALL has a dismal prognosis, with an unmet need for effective targeted therapies. Several unique challenges mean that CAR-T cell therapy has yet to be successfully translated to T-ALL. Most strategies have targeted pan-T cell antigens (CD7, CD5) but these are limited by T cell aplasia and fratricide, requiring elimination of CAR-T antigen surface expression during manufacture. An ideal target would be exclusively or largely confined to the malignant T cell component but published examples of these (CD1a and TRBC1) are expressed in only minor T-ALL subsets.We previously showed that CD21 is expressed in a NOTCH-dependent manner in T-ALL (Leukemia. 2013, 27:650) and have developed it as a potential immunotherapy target, being primarily expressed on normal B cells, with minimal expression on mature T cells.70% of human T-ALL cell lines (9/16) expressed surface CD21 by flow cytometry (FACS), with a median antigen density in positive lines of 2545/cell. In primary T-ALL, 57% of presentation samples (n=58) expressed CD21 (median antigen density 1168/cell). 45% of relapse (n=11) and 20% of primary refractory cases (n=30) expressed CD21, with a similar antigen density to presentation samples. CD21 positivity varied by maturational stage, with highest expression in cortical T-ALL (80% of cases) followed by pre-T (72%), mature (67%), ETP (25%) and pro-T (17%).Healthy donor blood (n=14) showed CD21 expression limited to B cells and a low proportion (11%) of T cells (10-fold lower intensity v B cells, 316 antigens/cell). T cell CD21 expression was not up-regulated upon activation with CD3/CD28 antibodies (n=6) and was not associated with markers of differentiation/exhaustion.To target CD21, DNA gene-gun vaccination of rats with a plasmid encoding full-length CD21, followed by phage display was performed and multiple anti-CD21 scFvs isolated. These were cloned into 4-1BBζ CARs and expressed in primary T cells but failed to kill or secrete cytokines in response to CD21+ SupT1 cells.CD21 is a bulky molecule, with 15/16 sushi repeats in the extracellular domain. All isolated scFvs were found to bind membrane-distal domains. We hypothesized that ineffective signalling due to inadequate synapse formation was responsible for poor performance of anti-CD21 CAR-T, and that binders to membrane-proximal epitopes would signal more efficiently. We re-vaccinated rats with the first 5 sushi repeats of CD21 and generated a library of binders which bound CD21 at this membrane-proximal region.Multiple candidate binders expressed as CARs were functional, with cytotoxicity and interferon-γ secretion in response to CD21+ target cells. However, non-specific background cytokine secretion was seen against CD21 negative cells, and no IL-2 secretion was seen. Re-cloning binders into a fragment antigen binding (Fab)-CAR architecture yielded constructs capable of specific cytotoxicity, IFN-γ and IL2 secretion against a CD21+ cell line but not its CD21 negative counterpart (n=6). Our lead anti-CD21 candidate CAR specifically proliferated in vitro, without fratricide or premature exhaustion/ differentiation, and was active against low-density CD21-positive cell lines (n=3) and primary cells from 2 T-ALL patients. Improved functionality of Fab v scFv-based CAR was not driven by higher affinity binding or CAR surface expression.We tested anti-CD21 CAR in murine models of T-ALL. NSG mice were injected with SupT1-luciferase cells and treated with aCD19 or aCD21 CAR-T on day +5. At 2 weeks post treatment, markedly lower disease burden was seen in CD21 CAR-T v CD19 recipients by bioluminescence imaging (median radiance 71700 v 790000 p=0.0079). Further, we injected primary T-ALL blasts in another cohort, treating with aCD19 or aCD21 CAR-T on D+20. Serial bleeds from day 27 post CAR-T showed tumour control in aCD21 CAR treated mice (p=0.024) with an overall survival advantage (median OS 44 days vs undefined, HR = 19.8, p = 0.0069, n=4/group).In summary, we propose CD21 as a novel target for CAR-T cell therapy in T-ALL. Its expression is largely restricted to the malignant T cell compartment, overcoming issues with fratricide and on-target off-tumour effects seen in many T-ALL CAR-T strategies to date. Despite the complexity of the target, we have successfully generated an aCD21 CAR that is functional both in vitro and in vivo. DisclosuresMaciocia: Autolus: Current equity holder in publicly-traded company. Onuoha: Autolus: Ended employment in the past 24 months. Khwaja: Pfizer: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Jazz Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Astellas: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Maciocia: Autolus: Current equity holder in publicly-traded company, Research Funding. Pule: Autolus: Current Employment, Current equity holder in publicly-traded company.

Factors Associated with Outcomes Among Refractory/Relapsed TP53-Mutated/Chromosome 17p Deletion Acute B-Cell Lymphoblastic Leukemia (B-ALL) Patients Treated with CD19-Targeted Chimeric Antigen Receptor (CAR)-T Therapy

IntroductionCD19-targeted chimeric antigen receptor (CAR)-T cell therapy effective for refractory/relapsed (R/R) B-cell acute lymphoblastic leukemia (B-ALL) that results in about 90% of complete remission (CR)/CR with incomplete blood recovery (CRi). According to a published study from our center that analyzed 254 R/R B-ALL patients, we confirmed that TP53 mutation was an independent prognostic factor of efficacy following CD19 CAR-T therapy. What factors affect the prognosis of patients with TP53 mutation/deletion treated with CD19 CAR-T is not clear. Here, we focus on the patients with TP53 mutation/deletion and analyze the factors associated with efficacy following CD19 CAR-T therapy among 64 B-ALL patients with TP53 mutation/chromosome 17p deletion.Patients and MethodsFrom June 2017 to February 2020, we analyzed 64 R/R patients (36 male, 28 female) with TP53 mutation/chromosome 17p deletion who received CD19 CAR T-cells from 5 clinical trials at Hebei Yanda Lu Daopei Hospital (NCT03173417, NCT02546739, NCT03312205 and NCT03671460 registered at https://clinicaltrials.gov; Chictr-onc-17012829 at www.chictr.org.cn). Among them, there were 42 patients with TP53 mutation only, 10 with chromosome 17p deletion, and 12 harboring both the mutation and deletion. There were 27 pediatric patients ≤ 14 years old and the remaining 37 patients were adults (>14 years old).ResultsAfter CAR-T therapy, 49/64 (76.6%) patients achieved CR/CRi on Day 30 and 1-year OS among the 64 patients was 39.4%. Other 15 patients who had no response (NR) to CAR-T therapy died within 1 year. Among the 49 patients who achieved CR after CD19 CAR-T, 1-year OS and 1-year relapse-free survival (RFS) were 50.0% and 40.9%, respectively. Thirty-three of the 49 patients subsequently bridged to allogeneic hematopoietic stem cell transplantation (allo-HSCT) with 1-year OS and RFS of 59.5% and 55.8%, respectively.Using univariate analysis of CR rates (Table 1), the pediatric patients demonstrated a lower CR rate compared to the adult patients (63.0% vs. 86.5%, p=0.04). We saw a trend of patients with complex cytogenetics having a relatively low CR rate compared to patients without complex cytogenetics yet no significant difference was observed (69.4% vs.85.7%, p= 0.15). For the TP53 functional mutation group versus the TP53 non-functional mutation group, CR rates were 70.0% vs. 92.8%, respectively (p= 0.15). In addition, patients with more than one TP53 mutations (≥ 2) showed a lower CR rate of 72.3% compared to patients with one TP53 mutation who achieved 100% CR (p= 0.18).Analyzing the data from all 64 patients, we identified three factors that were significantly associated with OS: 1) presence of complex cytogenetics (compared to without complex cytogenetics; p= 0.005), 2) achievement of CR/CRi (compared to NR; p< 0.001), and 3) bridging into allo-HSCT post CAR-T (compared to CAR-T only; p < 0.001).Next, we focused on analyzing the factors affecting the long-term efficacy of the 49 patients who achieved CR (Table 2). Two factors were associated with OS/RFS: 1) presence of complex cytogenetics (compared to no complex cytogenetics; 1-year OS of 60.1% vs. 39.8%, p=0.025; 1-year RFS 52.0% vs. 28.6%, p = 0.004, Figure 1), and 2) bridging into allo-HSCT post CAR-T (compared to CAR-T only; 1-year OS 59.5% vs. 28.1%, p = 0.003; 1-year RFS 55.8% vs. 7.7%, P < 0.001, Figure 2). Four additional factors that showed a trend of worse efficacy were 1) TP53 mutations more than one (≥2) (compared to one TP53 mutation; 1-year 53% vs. 21.4%, p=0.06; 1-year RFS 45.4% vs. 14.3%, p=0.15), 2) presence of TP53 mutations plus additional gene mutations (compared to TP53 mutation alone; 61% vs. 34.5%, p=0.07), 3) patients with extramedullary disease (EMD) (compared to without EMD; 1-year OS 59.6% vs. 20%, p= 0.05; 1-year RFS 47.7% vs. 20%, p=0.15), and 4) low risk evolutionary action score (EAp53) (compared to high risk; 1-year RFS 80% vs. 30.6%, p=0.12).ConclusionsThis study has uncovered factors that may predict treatment outcomes and duration of remission for patients with TP53 mutation/chromosome 17p deletion who received CD19 CAR-T therapy. Presence of complex cytogenetics and not bridging into allo-HSCT are two factors affecting the long-term efficacy. Further studies are needed to confirm these results, to improve the clinical management and personalization of treatment approaches for B-ALL patients harboring TP53 mutation/chromosome 17p deletion. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Polatuzumab Vedotin Use before Chimeric Antigen Receptor T-Cell (CAR-T) Therapy in Aggressive Lymphoma: A US Single Center Experience

Polatuzumab Vedotin Use before Chimeric Antigen Receptor T-Cell (CAR-T) Therapy in Aggressive Lymphoma: A US Single Center Experience

A Phase II Trial of Anakinra for the Prevention of CAR-T Cell Mediated Neurotoxicity

A Phase II Trial of Anakinra for the Prevention of CAR-T Cell Mediated Neurotoxicity

Dynamics and Management of CAR-T Cells Associated Cytopenias: A Single-Center Experience

* Martín-Rojas RM and Bailén R equally contributed to this work.INTRODUCTIONCAR-T cell therapy is approved by the European Medicines Agency (EMA) and the Federal Drugs Administration (FDA) for the treatment of adult patients with relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL) after two or more lines of systemic therapy and for children and adults up to age 25 with relapsed/refractory B-cell acute lymphoblastic leukemia (B-ALL). Prolonged cytopenias have been reported in up to 30-60% of patients undergoing CAR-T cell therapy, but information about its pathophysiology, dynamics and clinical impact is scarce.METHODSWe conducted a retrospective study of consecutive patients undergoing commercial CAR-T cell therapy in our center between June 2019 and March 2021. We analyzed peripheral blood cell counts pre-lymphodepletion, at admission and during the first year of follow-up. This information was correlated with clinical data and analytical parameters. This study was approved by our institutional Ethics Committee and it was performed in compliance with the Declaration of Helsinki. Data were analyzed using IBM SPSS Statistics version 24 and GraphPad Prism version 8.4.3.RESULTSA total of 40 patients were included, 37 with diagnosis of R/R DLBCL and 3 with B-ALL (Table 1). 6-month overall survival was 71% for patients with lymphoma and 33.3% for patients with B-ALL.The dynamics of neutrophil and platelet counts is shown in Figure 1. Median hospitalization duration was 25 days (range: 11-241) and, during this period, 10 patients (25%) required transfusion of 5 or more red cell concentrates (18.9% lymphoma vs. 100% B-ALL; p=0.002), 11 patients (27.5%) required 5 or more platelet transfusions (21.6% lymphoma vs. 100% B-ALL; p=0.003) and 6 patients needed 5 or more doses of G-CSF (13.5% lymphoma vs. 33.3% B-ALL; p=0.3).On day +28 post CAR-T cell therapy, 26 patients (65%) showed persistent profound cytopenias not related with marrow infiltration (absolute neutrophil counts ≤500/μL and/or platelets ≤50000/ μL): a total of 4 patients (15.4%) had neutropenia, 8 patients (31%) thrombopenia and 14 patients (54%) both. 100% of patients with B-ALL maintained aplasia at day +28, with no evidence of disease.Due to persistent cytopenias at discharge, 22 patients (64.7%) received outpatient treatment with G-CSF (20 lymphoma vs. 2 B-ALL; p=0.41), 13 patients (38.2%) received erythropoietin (11 lymphoma vs. 2 B-ALL; p=0.16) and 12 patients (35.3%) were treated with thrombopoietin analogues (10 lymphoma vs. 2 B-ALL; p=0.13). One patient with B-ALL received a boost of selected CD34+ cells from her donor (Table 1).On day +90 post CAR-T cell therapy, 7 patients (26.9%) showed profound cytopenias and, on day +180 it increased to 9 patients (47.4%). None of the 9 patients who were alive at one year follow-up, presented profound cytopenias at this point (Figure 2).Profound cytopenias on day +28 were related to bridging therapy (p=0.04), bone marrow infiltration at diagnosis (p=0.05), higher lymphodepletion doses (p=0.05), evidence of a bulky mass pre-lymphodepletion (p=0.007), development of cytokine release syndrome (CRS) (p=0.012), ICU admission (p=0.07), infectious complications (p=0.008) and having less than 2000/ μL neutrophils pre-lymphodepletion (p=0.04). A multivariate analysis using logistic regression identified higher doses of lymphodepletion (OR 7.57; 95% CI 1.14-50.4; p=0.03) and bone marrow infiltration at diagnosis (OR 7.31; 95% CI 0.97-54.95; p=0.05) as the only independent predictors factors of these cytopenias.Profound cytopenias on day +180 were related to bone marrow infiltration at diagnosis (p=0.02), having received bridging therapy (p=0.05) and lower pre-lymphodepletion lymphocyte counts (p=0.04) and folate levels (p=0.05). None of these variables reached statistical significancy on the multivariate analysis.CONCLUSIONSProfound cytopenias not associated with progression or relapse were a frequent complication after commercial CAR-T cell therapy, with 65% of cases on day +28, being the lymphodepletion dose and bone marrow infiltration at diagnosis independent predictors for its development. Beyond day +28, up to 47% patients showed profound cytopenias. A higher number of patients and longer follow-up are needed to confirm our findings and identify other potential prognosis factors for these cytopenias. [Display omitted] DisclosuresMartín-Rojas: Pfizer: Membership on an entity's Board of Directors or advisory committees; Celgene-BMS: Consultancy, Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees. Bailen: Pfizer, Kite-Gilead, Gilead: Honoraria. Oarbeascoa: Gilead: Honoraria, Speakers Bureau. Kwon: Novartis, Celgene, Gilead, Pfizer: Consultancy, Honoraria.

First-in-Human Clinical Study of a Novel CD7-Targeted Chimeric Antigen Receptor (CAR)-T Cell Therapy for Refractory/Relapsed Mixed Phenotype Acute Leukemia (MPAL)

IntroductionMixed phenotype acute leukemia (MPAL) is a rare subtype of acute leukemia with features of both acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML). The blast cells of MPAL express multilineage immunophenotypic markers and may have a shared B/T/myeloid phenotype. CD7 is expressed by the leukemic blasts and malignant progenitor cells of approximately 30% of AML patients. MPAL is usually associated with a relatively poor prognosis which is even worse compared to either AML or ALL, and even among patients that undergo allogeneic hematopoietic stem cell transplantation (allo-HSCT), underscoring the need for new therapies for these patients. CAR-T cell therapy has shown to be efficacious with a tolerable safety profile in a subset of hematological malignancies. Here, we explored the safety and efficacy of CAR-T therapy in treating refractory/relapsed (r/r) MPAL patients with CD7-positive in a phase I dose-escalation clinical study (https://clinicaltrials.gov NCT04938115).MethodsPeripheral blood (PB) mononuclear cells were obtained from patient themselves or patient transplant donors for those who relapsed post-transplant by leukapheresis. T-cells were purified using CD3+ magnetic beads or CD4+ and CD8+ magnetic beads. The second-generation CD7 CAR with a 4-1BB costimulatory domain was manufactured per the manufacturer's protocol. This phase I dose escalation study was initiated to explore the safety and efficacy of CD7 CAR-T in treating patients with MPAL. Prior to the CAR-T cells infusion, patients received systemic bridging chemotherapy due to rapid disease progression and then all patients received intravenous fludarabine (30mg/m 2/d) and cyclophosphamide (300mg/m 2/d) (FC) lymphodepleting chemotherapy for 3 consecutive days (Day -5 to Day -3). The median time from leukapheresis to CAR-T cell infusion was 14 days.ResultsFrom Nov. 2020 to June 2021, 5 adult acute leukemia patients with CD7-positive (4 MPAL, 1 FLT3-mutated AML) were enrolled and infused with CD7 CAR T-cells, one with a low-dose (1.5×10 5/kg), 2 with a medium dose (5.0×10 5/kg), and 3 with a high dose infusion (1.0×10 6/kg). The median transduction efficiency of products was 70.4% (range: 32.0%-96.9%). As of July 30, 2021 cut-off date, the median observation time was 37 days (range: 35-232 days). Characteristics of enrolled patients are shown in Table 1. The median age was 33 years (range: 21-37 years), and the median bone marrow (BM) blasts percentage by morphology was 28.0% (range: 2.5-51.5%) at enrollment. Four patients had prior allo-HSCT history including one who had extramedullary disease (EMD) who relapsed following a 2 nd transplant and had also received CD19 CAR-T cell therapy prior to enrollment in the current trial. The median interval period from prior transplant to CD7 CAR-T cell infusion was 16 months (range: 8-23 months). Following infusion, the median peak of circulating CD7 CAR-T cell was 1.17×10 5copies/μg (0.651~7.04×10 5copies/μg) genomic DNA which occurred around Day 21 (Day14 - Day21) and 59.2% (4.28%~74.58%) occurring on Day18 (Day11-Day21) by q-PCR and flow cytometry respectively (Fig.1).Four weeks post CD7 CAR-T cell infusion, 4/5 patients achieved complete remission (CR) or CR with incomplete blood recovery (CRi) in BM and all achieved minimal residual disease (MRD)-negative CR. One patient who relapsed post 2 nd transplant, also with EMD, achieved CR in BM, however, remission was not achieved in EMD through PET-CT evaluation on Day 35.One MRD-negative CR patient subsequently underwent consolidative allo-HSCT 120 days post CD7 CAR T-cell infusion and has remained in MRD-negative CR. Other 3 patients without consolidative allo-HSCT remained in MRD-negative CR till the last follow-up. All 5 patients developed cytokine release syndrome (CRS)-three of 5 patients had grade I CRS, one patient had grade II and one patient had grade III CRS. None of the patients had neurotoxicity. Among the 4 patients who had prior allo-HSCT, 1 developed grade I graft-versus-host disease post CAR-T therapy.ConclusionThis study demonstrated that CD7-targeted CAR-T therapy offers an opportunity to achieve CR for CD7-positive MPAL patients even for those who relapsed post-transplant. Safety was manageable, however, more data on additional patients and longer observation times are needed to further evaluate the efficacy of CD7 CAR-T products. [Display omitted] DisclosuresBa: SenlangBio: Current Employment.

A Phase 2/3 Randomized, Placebo-Controlled, Open-Label, Multi-Center Trial of Lenzilumab to Improve the Safety and Efficacy of CAR-T Cell Therapy in Adults with Relapsed or Refractory Large B-Cell Lymphoma (The SHIELD Study)

Background: Diffuse large B-cell lymphoma (DLBCL) is the most common aggressive sub-type of non-Hodgkin's lymphoma(Liu, et al. Am J Hematol 2019). All three approved CD19-directed CAR-T therapies (axicabtagene ciloleucel, tisagenlecleucel, lisocabtagene maraleucel) are associated with toxicities, including cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) that can be severe, resulting in non-relapse mortality, ICU admission, and significant non-drug related health resource utilization which represent barriers to access and adoption (Nabhan, et al. J Clin. Pathway 2017). Studies have shown that early elevation of granulocyte-macrophage colony-stimulating factor (GM-CSF) levels 1-day post CAR-T infusion correlates with severe ICANS (Rossi, et al. EMA Workshop 2016), which is a negative prognostic factor for overall survival (Karschnia, et al. Blood 2019). It has been proposed that upon contact with the tumor, CAR-Ts produce GM-CSF, which serves as a communication conduit between the specific immune response of CAR-T and the off-target inflammatory cascade produced by myeloid lineage cells, causing myeloid cells to expand and promote the production of other downstream proinflammatory chemokines (MCP-1, IL-8, IP-10), cytokines (IL-1, IL-6), and other markers of systemic inflammation (CRP, Ferritin) (Sterner, et al. Blood 2019). Moreover, IL-6 is predominately released by tumor cells in a contact-independent manner (Barrett et al. Blood 2016), which helps explain why the prophylactic administration of tocilizumab is not effective in reducing the overall incidence of CRS or ICANS, as this cytokine is downstream in the inflammatory cascade. Further, the prophylactic use of tocilizumab has been shown to increase the incidence of all-grades and grade >3 ICANS (Locke, et al. Blood 2017). Lenzilumab is a novel Humaneered ® monoclonal antibody that neutralizes GM-CSF and has demonstrated potential to reduce the hyper-immune mediated cytokine storm induced by SARS-CoV-2 infection and significantly improve the likelihood of survival without ventilation in hospitalized COVID-19 patients, as reported in the LIVE-AIR phase 3 study (Temesgen, et al. medRxiv 2021). Methods: Eligible patients are adults (≥ 18 y) with relapsed or refractory DLBCL or are chemorefractory. Prior therapy must have included an anti-CD20 monoclonal antibody and an anthracycline-containing regimen. Patients will undergo leukapheresis and may receive optional corticosteroid bridging therapy. Patients will then receive lymphodepleting chemotherapy on Days ‒3 to ‒5 followed by infusion of lenzilumab on Day 0, 6-hrs prior to CAR-T infusion. Approximately 40 accredited sites across the U.S. certified to administer the three commercially available CAR-Ts have been engaged to participate in this 2-part study. In Part 1, all patients will receive lenzilumab 1800mg via a single 2-hour infusion prior to CAR-T administration. The objective of Part 1 is to evaluate the optimal regimen and assess whether a second dose of lenzilumab post-CAR-T infusion is required. A translational assessment of GM-CSF axis suppression, levels of CAR-T cells in blood, other inflammatory markers and lenzilumab PK/PD will be evaluated, along with the incidence and severity of CRS and ICANS, objective response rates (ORR) and rates of complete response (CR) by Day 28 to select the optimal regimen to carry forward into Part 2. The objective of Part 2 is to confirm whether lenzilumab can improve the toxicity and tolerance of CAR-T while maintaining or improving efficacy and durability of response. Up to 250 patients will be randomized 1:1 to receive lenzilumab or placebo with CAR-T per standard of care. The primary endpoint of the study is incidence of grade >2 CRS and/or ICANS by Day 28, with a key secondary endpoint of CR at 6-months in patients without grade ≥ 2 CRS and/or ICANS at Day 28 (Toxicity-free CR). This design and sample size yields 90% power to detect a 50% reduction in the primary outcome measure. Secondary endpoints include incidence of all grades and grade >3 CRS and/or ICANS, respectively; ORR and CR at 1, 3, 6, 12 months; durability of CR; progression-free survival, overall survival and health related quality of life using validated patient reported outcome measures. In addition, the study will explore the CRS and ICANS grading criteria that have been utilized with each of the approved CAR-Ts. DisclosuresKenderian: Humanigen, Inc.: Consultancy, Honoraria, Research Funding. Durrant: Humanigen, Inc.: Current Employment, Current equity holder in publicly-traded company, Divested equity in a private or publicly-traded company in the past 24 months. Chappell: Humanigen Inc.: Current Employment, Current equity holder in publicly-traded company, Divested equity in a private or publicly-traded company in the past 24 months. Ahmed: Humanigen Inc.: Current Employment, Current equity holder in publicly-traded company. Kilcoyne: Humanigen, Inc.: Current Employment, Current equity holder in publicly-traded company.

How to Sequence Therapies in Diffuse Large B-Cell Lymphoma Post-CAR-T Cell Failure.

Post CAR-T failures represent a new unmet need in R/R LBCL. The prognosis is usually very poor and standard treatment options that can guide clinicians are, unfortunately, not available. While polatuzumab, tafasitamab, selinexor, and loncastuximab tesirine are available as SOC since they are FDA approved, data is lacking in the post CAR-T setting. However, they could be used in the absence of other treatment options (clinical trials). A selected group of patients may be treated with checkpoint inhibitors, likely low tumor burden or low proliferative lymphomas or those with PD-L1 expression. For localized relapses, radiation therapy could be considered. A main consideration should be given to clinical trials. So far, it appears that bi-specific antibodies have the best encouraging data (high response rates) with manageable toxicities and logistics; thus, we recommend clinicians to enroll patients in clinical trials utilizing these agents. Other cell therapies (such as dual CAR-T or allogeneic products) should also be considered; however, challenges with logistics and further immunosuppression (especially if patients had prolonged cytopenias from prior CAR-T therapy) may affect its applicability right after CAR-T relapse. It is unclear whether these options will lead to long-term remissions; thus, consolidation with stem cell transplantation (either auto or allogeneic SCT) could be considered in eligible patients.