Immunotherapy: SYNERGISTIC PERITONEAL ANTI-TUMOR EFFECT OF ALLOCETRAOTS, A CELLULAR IMMUNE-THERAPY, IN COMBINATION WITH IMMUNE CHECKPOINT INHIBITORS/CHEMOTHERAPY, THROUGH IN-VIVO REPROGRAMMING OF MACROPHAGES AND DENDRITIC CELLS

Background & Aim: Immune checkpoint inhibitors (ICI) revolutionized solid tumor treatment, however, in many tumors only partial response is achieved. Allocetra-OTS has an immune modulating effect on macrophages and dendritic cells and showed an excellent safety profile in patients including patients with sepsis and Covid-19. Here we investigated the anti-tumoral effect of Allocetra-OTS cellular therapy, in peritoneal solid tumor animal models. Methods, Results & Conclusion(s): Allocetra-OTS is manufactured from enriched mononuclear fractions and induced to undergo early apoptosis. Balb/c mice were inoculated intraperitoneally (IP) with AB12 (mesothelioma) with pLenti-PGK-V5-Luc-Neo and treated with anti- CTLA4 with or without Allocetra-OTS. Mice were monitored daily for clinical score and weekly using IVIS (Fig.1). Kaplan-Meier log rank test was done for survival. For Allocetra-OTS preparation, enriched mononuclear fractions were collected by leukapheresis from healthy eligible human donors and induced to undergo early apoptosis. Anti- CTLA4 standalone therapy significantly improved survival (Fig.2) from mean 34+/-9 to 44.9 +/-20 days. However, OTS standalone therapy was non-inferior and improved survival to 52.3 +/-20 days. Anti-CTLA4 + Allocetra-OTS combination therapy, ameliorated survival to 86.7+/-20 days with complete cancer remission in 60-100% of mice. Similar anti- tumoral effects of Allocetra-OTS were seen in mesothelioma model in a combination therapy with either anti-PD1 or cisplatin and using anti-PD1 in ID8 ovary cancer model. Based on single cell analysis confirmed by flow cytometry and pathology, the mechanism of action seems to be related or at least associated with an increase in f/480high peritoneal macrophages and a decrease in recruited macrophages, and to f/480high infiltration of the tumor. However, further studies are needed to confirm these observations. During IP tumor progression, Allocetra-OTS as a standalone therapy or in combination with ICI, or cisplatin, significantly reduced tumor size and resulted in complete remission in up to 100% treated mice. Similar results were obtained in ID8 ovary cancer. Based on excellent safety profile in > 50 patients treated in prior clinical trials for sepsis and Covid-19, Phase I/II clinical trial of Allocetra-OTS plus chemotherapy has started and three patient already recruited. A second phase I/II clinical trial of Allocetra- OTS plus anti-PD1, as a second- and third-line therapy in various cancers, was initiated in Q1 2023. [Figure presented]Copyright © 2023 International Society for Cell & Gene Therapy

Prophylactic Corticosteroid Use with Axicabtagene Ciloleucel (Axi-Cel) in Patients (Pts) with Relapsed/ Refractory Large B-Cell Lymphoma (R/R LBCL): 2-Year Follow-up of Zuma-1 Cohort 6

Background: The ZUMA-1 safety management Cohort 6 (N=40), which evaluated whether prophylactic corticosteroids and earlier corticosteroids and/or tocilizumab could improve safety outcomes, demonstrated an improved safety profile (no Grade >=3 cytokine release syndrome [CRS];15% Grade >=3 neurologic events [NEs]) vs pivotal Cohorts 1+2, without compromising response rate or durability (95% ORR, 80% CR rate, and 53% ongoing response rate with >=1 y of follow-up;Oluwole, et al. ASH 2021. 2832). Here, 2-y updated outcomes are reported. Method(s): Eligible pts with R/R LBCL underwent leukapheresis (followed by optional bridging therapy) and conditioning chemotherapy, then a single axi-cel infusion. Pts received corticosteroid prophylaxis (once-daily oral dexamethasone 10 mg on Days 0 [before axi-cel], 1, and 2) and earlier corticosteroids and/or tocilizumab for CRS and NE management vs Cohorts 1+2 (Oluwole, et al. Br J Haematol. 2021). The primary endpoints were incidence and severity of CRS and NEs. Secondary endpoints included ORR (investigator-assessed), duration of response (DOR), progression-free survival (PFS), overall survival (OS), and chimeric antigen receptor (CAR) T-cell levels in blood. Result(s): As of December 16, 2021, the median follow-up time for the 40 treated pts was 26.9 mo. Since the 1-y analysis, no new CRS events were reported (no pts had Grade >=3 CRS to date). The incidence of Grade >=3 NEs increased from 15% to 18%between the 1-y and 2-y analyses. Two new NEs occurred in 2 pts: 1 pt had Grade 2 dementia (onset on Day 685 and ongoing at time of data cutoff;not related to axi-cel) and 1 had Grade 5 axi-cel-related leukoencephalopathy. Since the 1-y analysis, 6 new infections were reported (Grades 1, 2, and 5 COVID-19 [n=1 each], Grade 3 Pneumocystis jirovecii pneumonia [n=1], Grade 3 unknown infectious episode with inflammatory syndrome [n=1], and Grade 2 herpes zoster [n=1]). In total, 8 deaths occurred since the 1-y analysis (progressive disease [n=5], leukoencephalopathy [n=1], and COVID-19 [n=2]). The ORR was 95% (80% CR), which was unchanged from the 1-y analysis. Median DOR and PFS were since reached (25.9 mo [95% CI, 7.8-not estimable] and 26.8 mo [95% CI, 8.7-not estimable], respectively). Median OS was still not reached. Kaplan- Meier estimates of the 2-y DOR, PFS, and OS rates were 53%, 53%, and 62%, respectively. Of 18 pts (45%) in ongoing response at data cutoff, all achieved CR as the best response. By Month 24, 14/20 pts with evaluable samples (70%) had detectable CAR T cells (vs 23/36 pts [64%] in Cohorts 1+2). Conclusion(s): With 2 y of follow-up, the ZUMA-1 Cohort 6 toxicity management strategy continued to demonstrate an improved long-term safety profile of axi-cel in pts with R/R LBCL. Further, responses remained high, durable, and similar to those observed in Cohorts 1+2 (Locke, et al. Lancet Oncol. 2019).Copyright © 2023 American Society for Transplantation and Cellular Therapy

Anaphylaxis to Cyclophosphamide Metabolites during Lymphodepletion for CAR-T Therapy

Background: Cyclophosphamide (Cy) is used in hematopoietic stem cell transplant (HSCT) preparative regimens and lymphodepletion for chimeric antigen receptor T-cell (CAR-T) therapy. We describe a case of cyclophosphamide hypersensitivity in a pediatric patient during CAR-T therapy. Case description: A 13 year old boy was diagnosed with very high risk ALL in 2015 and had 2 isolated CNS relapses treated with intensified chemotherapy (chemo) and cranial radiation (1st relapse) and Blinatumomab with intrathecal (IT) chemo followed by sibling donor HSCT (2nd relapse). At age 19, and 18 months after HSCT, he had a 3rd CNS relapse treated with IT chemo and referral for CAR-T therapy. At our center, leukapheresis and CAR-T production (Novartis) were performed. Later, during lymphodepletion with fludarabine (Flu) and Cy, physiologic replacement hydrocortisone (HC) was briefly held to prevent interference with CAR-T function. After 3 days of Flu/Cy, he developed fever and hypotension requiring inotropic support. Hypotension and fever resolved with stress dose HC and antibiotics and was attributed to culture-negative sepsis and adrenal crisis. CAR-T infusion was subsequently delayed by skin GVHD requiring glucocorticoids and COVID-19 infection treated with convalescent plasma and nirmatrelvir/ritonavir. Physiologic HC replacement was continued when he was re-admitted for CAR-T therapy, but he again developed fever, diffuse erythema and shock in hours following the first dose of Cy necessitating stress dose HC, antibiotics, inotropes, and mechanical ventilation. Negative blood cultures and ongoing physiologic HC replacement suggested an alternative explanation for shock. Case reports of anaphylaxis to Cy metabolites implicated Cy as the causative agent so it was discontinued. After recovery, CAR-T cells were infused without complications. In the following weeks, he had no evidence of recurrent leukemia but was persistently pancytopenic. A sibling donor stem cell boost was proposed but the patient accepted only palliative care. He had several opportunistic infections before succumbing to E. coli sepsis. Discussion(s): The first episode of shock was initially attributed to adrenal crisis and sepsis, although no organism was identified. The second episode appeared anaphylactic in timing and clinical presentation with adequate HC replacement and negative cultures, suggesting Type I hypersensitivity. The patient previously received Cy uneventfully before HSCT, suggesting that the donor-derived immune system was the source of new Cy hypersensitivity. Onset of anaphylaxis within hours rather than minutes after Cy administration supports hypersensitivity to Cy metabolites rather than to the drug itself. This case highlights the importance of consideration of sensitivity to Cy metabolites as well as acquired donor-specific allergy even when alternative explanations are likely.Copyright © 2023 American Society for Transplantation and Cellular Therapy

Prognosis Score for Overall Survival with CAR-T Therapy in Aggressive Lymphoma

Background: Despite the transformative potential of chimeric antigen receptor T (CAR-T) therapy, more tools to assist with identifying patients with increased likelihood of benefitting from this therapy will be helpful, particularly given the logistical complexity and socio-economic demands for CAR-T relative to other therapies. Health care resource restriction during the COVID-19 pandemic highlights the need for these tools. We present a simple survival score that uses 3 readily available clinical labs: platelet (plt), absolute lymphocyte count (ALC), and Lactate dehydrogenase (LDH), to predict the risk of dying within 6 months of CAR-T therapy in patients with aggressive lymphoma. Method(s): We conducted a retrospective chart review of patients with aggressive non-Hodgkin lymphoma (NHL) who received FDA-approved CAR-T between Jan 2018 to Jan 2022 at Mayo Clinic Rochester.(Table Presented)Results: Among a total of 110 pts who received CAR-T, 27 (25%) pts died within the first 6 months post CAR-T infusion (OS <= 6 months). Disease progression was the main cause of death (18/25, 72%), followed by infection (4/25, 16%), CAR-T related (HLH/MAS, 2/25, 8%), second primary malignancy (1/25, 4%) and unknown (2/25, 8%).Baseline demographics were comparable between the OS>6months and <=6months groups (Table 1). Patients' ECOG, Karnofsky performance status and 11 labs at the time of evaluation for CAR-T therapy (initial eligibility assessment, prior to leukapheresis) were compared between those who died from any cause within 6 months of CAR-T infusion and those who did not. Hemoglobin, plt, ALC, absolute monocyte count, CRP, ferritin, and LDH were selected as clinically and/or statistically significant variables for multivariate testing. Multivariate regression with boot-strap testing identified plt, ALC, and LDH as the most predictive variables with 80.9+/-11.7% accuracy for predicting death within 6 months of CAR-T infusion. Patients were scored 0-3 using these 3 labs, with 1 point assigned for plt <= 100 X109/L, ALC <= 0.4 X109/L, or LDH > 222 U/L (upper limit of normal). OS by this survival score is shown in Figure 1.(Figure Presented)Discussion: Due to the curative potential of CAR-T, patients with broader characteristics than those treated on registration studies have been treated in standard of care practice. While an estimated 5%-10% risk of CAR-T associated deaths in the first 3 months is seen across all patients in clinical trials, predictors for early death after CAR-T in real-world patient populations can provide additional context for pts and providers when selecting treatment. This survival score is important proof of concept that a simple model using readily accessible clinical labs at the time of CAR-T evaluation could provide additional context to help with additional clinical decision-making. Multicenter prospective studies will help define and validate the definitive survival scoring system.Copyright © 2023 American Society for Transplantation and Cellular Therapy

A secondary CD34+ acute lymphoblastic leukemia unmasked and mobilized by G-CSF in an autologous stem cell donor with testicular cancer.

BACKGROUND: Late complications of chemotherapy include treatment-related secondary leukemias. We describe an unusual case of a new treatment-related acute lymphoblastic leukemia (t-ALL) that was unmasked and mobilized by G-CSF during autologous hematopoietic progenitor cell collection (HPCC) in a young man with testicular cancer. METHODS: Electronic chart review of the patient medical history and pertinent laboratory findings. Patient CD34 and blast results were compared to 4249 autologous and 437 allogeneic HPCC performed between 2004 and 2022. In autologous donors, the %blast and %CD34 were compared by linear regression and paired t-test using commercial software. RESULTS: The patient was a 21-year-old male with relapsed testicular cancer referred for G-CSF cytokine-only mobilization and autologous HPCC. His pre-mobilization WBC count and differential were normal. On the day of HPCC, his WBC = 37.9 K/mcL with 12% blasts and 9.75% circulating CD34+ cells. The patient was admitted 9 days after HPCC with a normal WBC count and 15% blasts. He was diagnosed with a pro-B t-ALL bearing an t(4:11)(q21:q23) translocation and KMT2A-AF4 rearrangement. Upon review, this patient had the highest %CD34 among 4686 HPCC and was the only donor with %CD34 > 1% after a cytokine-only mobilization. CONCLUSION: We report a case of t-ALL that mimicked CD34+ HPC and was mobilized by high-dose G-CSF. Up to 70% of secondary leukemias bear 11q23/KMT2A rearrangements, which occur at the multipotent stem cell stage and can result in myeloid and lymphoid leukemias. Donors who have received past chemotherapy, especially with topoisomerase II inhibitors, are at increased risk for 11q23/KMT2A leukemias.

LISOCABTAGENE MARALEUCEL (LISO-CEL) AS SECOND-LINE THERAPY FOR R/R LARGE B-CELL LYMPHOMA (LBCL) IN PATIENTS NOT INTENDED FOR HSCT: PRIMARY ANALYSIS FROM THE PHASE 2 PILOT STUDY

Background: Patients with relapsed or refractory (R/R) LBCL after first-line treatment who are unable to undergo high-dose chemotherapy (HDCT) and hematopoietic stem cell transplantation (HSCT) hae poor outcomes and limited treatment options. Aims: PILOT (NCT03483103) ealuated liso-cel, an autologous, CD19-directed chimeric antigen receptor (CAR) T cell product, as second-line treatment in patients with R/R LBCL not intended for HSCT. Methods: Eligible patients were adults with R/R LBCL after first-line treatment who were not deemed candidates for HDCT and HSCT by their physician and met ≥ 1 frailty criteria as follows: age ≥ 70 years, Eastern Cooperatie Oncology Group performance status (ECOG PS) of 2, diffusing capacity for carbon monoxide ≤ 60%, left entricular ejection fraction < 50%, creatinine clearance < 60 mL/min, or alanine aminotransferase/aspartate aminotransferase > 2 × the upper limit of normal. Bridging therapy was allowed. Patients receied lymphodepletion with cyclophosphamide and fludarabine, followed 2-7 days later by liso-cel infusion at a target dose of 100 × 106 CAR+ T cells. Cytokine release syndrome (CRS) was graded per Lee 2014 criteria. Neurological eents (NE) were defined as inestigator-identified neurological aderse eents related to liso-cel and graded using the National Cancer Institute Common Terminology Criteria for Aderse Eents, ersion 4.03. The primary endpoint was objectie response rate (ORR) per independent reiew committee;all patients had ≥ 6 months of follow-up from first response. Results: Of 74 patients who underwent leukapheresis, 61 receied liso-cel and 1 receied nonconforming product (ie, product wherein one of the CD8 or CD4 cell components did not meet one of the requirements to be considered lisocel). Common reasons for preinfusion dropout included death and loss of eligibility (5 each). For liso-cel-treated patients, median age was 74 years (range, 53-84;79% ≥ 70 years) and 69%, 26%, and 5% met 1, 2, and 3 frailty criteria, respectiely;26% had ECOG PS of 2 and 44% had Hematopoietic Cell Transplantation-specific Comorbidity Index score ≥ 3. After first-line treatment, 54% were chemotherapy refractory, 21% relapsed within 12 months, and 25% relapsed after 12 months;51% of patients receied bridging chemotherapy. Median (range) onstudy follow-up was 12.3 months (1.2-26.5). ORR and complete response rate were 80% and 54%, respectiely (Table). Median duration of response and progression-free surial were 12.1 months and 9.0 months, respectiely. Median oerall surial has not been reached. The most frequent treatment-emergent aderse eents (TEAE) were neutropenia (51%), fatigue (39%), and CRS (38%), with grade 3 CRS in 1 patient (2%) and no grade 4/5 CRS eents. Any-grade NEs were seen in 31% (n = 19) of patients;grade 3 NEs occurred in 5% (n = 3) of patients and no grade 4/5 NEs were reported. Seen percent (n = 4) receied tocilizumab only, 3% (n = 2) receied corticosteroids only, and 20% (n = 12) receied both tocilizumab and corticosteroids for treatment of CRS and/or NEs. Oerall, grade ≥ 3 TEAEs occurred in 79% (n = 48) of patients, with grade 5 TEAEs in 2 patients (both due to COVID-19). Two patients (3%) had grade 3/4 infections and 15 (25%) had grade ≥3 neutropenia at Day 29. Summary/Conclusion: In the PILOT study, liso-cel as second-line treatment in patients with LBCL who met ≥ 1 frailty criteria and for whom HSCT was not intended demonstrated substantial and durable oerall and complete responses, with no new safety concerns. (Table Presented).

HIGH COMPLETE RESPONSE RATE FOLLOWING POINT-OF-CARE ANTI CD19 CAR T-CELL THERAPY IN PATIENTS WITH RELAPSED/REFRACTORY FOLLICULAR LYMPHOMA

Background: Patients with relapsed/refractory follicular lymphoma (R/R FL) often experience multiple relapses and require various lines of therapy. The ELARA and ZUMA-5 trials demonstrated high response rates along with acceptable safety profiles. We perform a phase 1b/2 single-center clinical trial of autologous point-of-care (POC) academic anti-CD19 chimeric antigen receptor (CAR) T-cells for patients with R/R FL treated with at least 2 lines of systemic therapy (NCT02772198). Aims: To report outcomes of POC CAR T-cell therapy in patients with R/R FL. Methods: Adults with R/R FL underwent a single leukapheresis procedure. Fresh peripheral blood mononuclear cells were isolated, activated, and transduced with a gammaretrovirus encoding for a CD19 CAR (based on an FMC63-derived ScFv, a CD28 costimulatory domain, and a CD3-ζ signaling domain). Lymphodepletion included fludarabine 25 mg/m2 over 3 days (days-4 to-2) and cyclophosphamide 900 mg/m2 once (day-2), followed by infusion of 1×106/kg CAR T-cells in the inpatient setting. Primary endpoints were response (by PET-CT, per Lugano criteria) at day 28, best response, and safety. Secondary endpoints included overall survival, progression-free survival (PFS), and production feasibility. Last follow-up was as of 02/2022. Results: All 19 patients enrolled received CAR T-cell infusion in a median of 11 days (IQR 10-11) after leukapheresis. The median age was 61 years (IQR 52-66). Five (26%) patients had Karnofsky performance status < 90%. Disease stage at enrollment was III-IV in 16 (84%) patients. Two (11%) patients had bulky disease;8 (42%) had LDH > upper limit of normal;and 16 (84%) had Follicular Lymphoma International Prognostic Index ≥ 3. Disease status at enrollment was progressive disease (n=14, 74%), stable disease (n=3, 16%), or partial response (PR;n=2, 11%). Twelve patients (64%) were refractory to last treatment. Disease grade at most recent lymph node biopsy was 1 (n=3, 16%), 2 (n=11, 58%), or 3a (n=5, 26%). The median time from FL diagnosis was 3.9 years (IQR 2.5-4.6). Sixteen (84%) patients had progression of disease within 24 months of initial therapy. The number of prior therapies was ≥ 4 in 6 (32%) patients;and 5 (26%) patients underwent prior autologous transplantation. Grade III-IV cytokine release and immune effector cell-associated neurotoxicity syndromes occurred in 1 (5%) and 4 (21%) patients, respectively. One patient was infected with COVID-19 on the 5th day following cell infusion and was admitted to the intensive care unit. One patient had grade 3 atrial fibrillation. Severe neutropenia (absolute neutrophil count <500/μL), thrombocytopenia (platelets <50K/μL) and anemia (hemoglobin <10g/dl) occurred in 15 (79%), 5 (26%), and 7 (37%) patients, respectively. No bleeding events or death were recorded following cell infusion. Response was evaluated in all patients. Overall response rate on day 28 was 84% (79% complete response [CR]). One patient with PR on day 28 achieved a CR after a year of follow-up. Three patients (16%) continued to progress following CAR infusion. All patients were alive at the last follow-up (median follow-up, 11.5 months [IQR 4-21]). One-year PFS was 74% (95% CI, 53-100). The median duration of response (DOR) was not reached (95% CI, 12.5-not reached). Estimated DOR at 1-year was 89% (95% CI, 71-100). Image: Summary/Conclusion: Point-of-Care anti-CD19 CAR T-cell therapy, performed following a very short production time, induced high CR rate with an acceptable safety profile in a cohort of patients with high-risk R/R FL.

In-vivo reprogramming macrophages and dendritic cells with Allocetra-OTS: Successful mono- and combination-antitumor therapy

Background: Chimeric antigen receptor (CAR) T cells can activate an immune response to a cancer-specific antigen but is less effective in solid tumors. Immune check point inhibitors (ICI) revolutionized the treatment of solid tumors, however, in many tumors only partial response is achieved. Here we questioned the role of synergistic effect of Allocetra-OTS (cellular therapy for in-vivo reprogramming macrophages and dendritic cells, Enlivex Therap.) on solid tumor progression. Methods: To follow tumor growth in vivo, HeLa-CD19 cells were stably transduced with pLenti-PGK-V5-Luc-Neo. For CAR preparation, fresh mononuclear cells (MNC) were transfected with CD19-CAR plasmids. For the intraperitoneal solid tumor model, SCID-Bg mice were injected intraperitoneally (IP) with human HeLa- CD19 or HeLa-CD19-luciferase cells, 10×106 allocetra-OTS or vehicle, and 10×106 CD19-CAR T cells or mock T cells. In an immune-competent model, Balb/c mice were treated IP with AB12 (mesothelioma) with pLenti-PGK-V5-Luc-Neo and treated with anti-CTLA4 with or without Allocetra-OTS. Mice were monitored daily for clinical signs and peritoneal fluid accumulation and weekly for tumor growth. Kaplan-Meier log rank test was done for survival. Peritoneal cells were evaluated using single cell analysis and flow cytometry. Tumors were examined for bacterial presence by immunohistochemistry staining with antilipoteichoic acid (LTA) and antilipopolysaccharide (LPS). For allocetra-OTS preparation, enriched mononuclear fractions were collected by leukapheresis from healthy eligible human donors and induced to undergo early apoptosis. Results: SCID mice survived 30±5 days (range 27-37) and were sacrificed or died from solid tumor in the peritoneal cavity after accumulation of bloody peritoneal fluid and clinical deterioration. Results were verified using IVIS of intraperitoneal HeLaCD19- Luc cells. CAR T cell therapy significantly ameliorated survival to 55±11 days (p < 0.05 vs MOCK) but Alloctra-OTS further ameliorated survival to 75±10 (p < 0.001) with 20-40% complete remission. In AB12 model, anti CTLA4 therapy significantly ameliorated survival from 26±5 to 38 ±9 days (p < 0.05). However, Allocetra-OTS monotherapy ameliorated survival to 45 ±12 days (p < 0.02) and combinational therapy to 75±9 days (p < 0.0001) with complete remission in 60-75% of mice. Single cell analysis revealed that restoration of large peritoneal macrophages (LPM), were associated with antitumor activity. Conclusions: During intraperitoneal tumor progression, allocetra-OTS as monotherapy or combinational therapy with CAR or anti-CTLA4 significantly reduced tumor size and enable complete remission in up to 75% treated mice. Based on excellent safety profile in > 30 patients treated for sepsis and Covid19, human phase I/II of allocetra-OTS plus ICI, for peritoneal metastases, is planned for 2022.

Immunotherapy: TREATMENT WITH ALLOCETRA-OTS APOPTOTIC CELLS IN 21 SEVERELY/CRITICALLY ILL PATIENTS WITH COVID-19

Background & Aim: COVID-19 has become pandemic, with mortality estimated between 1–4% )in alpha and delta variants) and complications among hospitalized patients resulting in up to 15–25% of inpatients being admitted to the intensive care unit (ICU). Two studies (one of 5 and and of 16 patients), were designed to determine the safety and efficacy of treatment with Allocetra-OTS for reprogramming macrophages and resolution of cytoikine storm in patients with severe/critical COVID-19. The two studies were approved by the Ministry of Health’s (MOH) Ethical Committee. Methods, Results & Conclusion: Methods: 2 clinical studies were done in three medical centres in Israel. Patient inclusion criteria was mainly severe or critical condition by NIH criteria. Further details are found in NCT04590053 and NCT04513470.18/21 had significant ARDS. An enriched MNC fraction was collected via leukapheresis from healthy, eligible human donors, prepared by Enlivex Ltd. and gamma irradiated. Apoptosis and viability of apoptotic cells were determined using Annexin V- and PI staining (Medical & Biological Laboratories, Nagoya, Aichi, Japan). Lack of proliferation was shown using CFSE and bead stimulation. Every patient recived one dose of 109 cells. Results. administration of Allocetra-OTS in 21 patients (11 severe and 10 critical with non ivasive oxygen support) with severe-to-critical Covid-19, of whom was safe with 5 unrelated SAEs. Allocetra-OTS was well tolerated when given in conjunction with standard therapy (remdesivir, enoxaparin, and dexamethasone) and showed early recovery;5.5 days in average till discharge. 2/21 patients were still hospitalized by (Figure Presented) day 28 (end of study).18 patients had mild-to severe ARDS and 16/18 (88.8%) completely recovered within few days. The cytokine storm was resolved in all discharged patients as shown by laboratory and 30 cytokine/chemokine measurements (Fig. 1 shows pro-inflammatory cytokines). Conclusion: Allocetra showed excellent safty profile and promising results regarding resolution of inflammation and respiratory failure, A double blind large comparative study in this population is now recruiting patients in 3 countries.

Long-term outcomes of patients with large B-cell lymphoma treated with standard-of-care axicabtagene ciloleucel: Results from the us lymphoma CAR-T cell consortium

Introduction: Axicabtagene ciloleucel (axi-cel) is an autologous anti-CD19 Chimeric Antigen Receptor (CAR) T-cell therapy that induces durable responses in patients with relapsed or refractory large B-cell lymphoma. At a median of 27.1 months follow-up on the ZUMA-1 trial, median overall survival (OS) was 25.8 months with 39% progression free survival (PFS) at 2 years post-infusion (Locke, Lancet Onc 2019). We previously reported outcomes of axi-cel patients treated with standard of care therapy at a median follow up of 12.9 months, including 42% who did not meet eligibility criteria for ZUMA-1 based on co-morbidities (Nastoupil, JCO 2020). Here we report results from this cohort at a median follow up of 32.4 months, as well as late outcomes of interest including cytopenias, infections and secondary malignancies. Methods and Results: The US Lymphoma CAR-T Consortium comprised of 17 US academic centers who contributed data independent of the manufacturer. Two hundred and ninety-eight patients underwent leukapheresis with intent to manufacture standard of care axi-cel as of September 30, 2018. In infused patients (n=275), OS and PFS were calculated from date of infusion. After median follow-up of 32.4 months (95% CI 31.1 - 34.3), median OS was not reached (95% CI 25.6 - not evaluable) (Figure 1A) with 1-, 2- and 3-year OS of 68.5% (95% CI 62.6-73.7), 56.4% (95% CI 50.1-62.2) and 52.2% (95% CI 45.7-58.2%), respectively. Median PFS was 9 months (95% CI 5.9-19.6) (Figure 1B);1-, 2- and 3-year PFS was 47.4% (95% CI 41.4-53.2), 41.6% (95% CI 35.6-47.5) and 37.3% (95% CI 31.3-43.2), respectively. Twenty-seven PFS events occurred at or after 1 year post infusion;19 events were progressive lymphoma, with the latest relapse observed 28 months after axi-cel infusion. Eight patients died while in remission from their lymphoma: 4 from secondary malignancy, 3 from infection, and 1 from unknown causes. Results of multivariable modeling were similar to our prior analysis: factors associated with both a shorter PFS and shorter OS included male sex, elevated pre-lymphodepletion LDH, and poor ECOG status. Complete blood count and B- and T-cell recovery data were collected at 1 and 2-years post-infusion, excluding patients who had relapsed or been treated for secondary malignancy at time of collection (Table 1). Rates of neutropenia (absolute neutrophil count ≤1000) at 1- and 2- years were 9.2% (10/109) and 11.2% (9/80) and rates of CD4 count ≤200/ul were 62% (23/37) and 27% (7/26). Recovery of B cells was seen in 54% (15/28) and 57% (13/23) at 1-and 2-years post infusion. Infections were reported in 31.2% (34/109) patients between 6- and 12-months post infusion, and 17% (18/109) were severe, requiring either hospitalization and/or IV antibiotics. Twenty-one patients (24%, 21/89) had an infection between 1- and 2- years, 11% of which were severe. Twenty percent (10/49) of patients between 2- and 3-years had an infection and 4 (8%) were severe. Neutropenia, low CD4 counts, and IgG levels were not associated with infection, though patients with infection between 6-12 months were more likely to have received IVIG (p<0.001). No patient in this cohort died of COVID-19. Twenty-two of 275 (8%) patients were diagnosed with subsequent malignancy after axi-cel treatment: 14/275 (5%) patients were diagnosed with myeloid malignancies (MDS (n=12), AML (n=1), CMML (n=1));other malignancies included squamous cell carcinoma of skin (n=3);sarcoma (n=1);endometrial (n=1);lung (n=1);mesothelioma (n=1) and AITL (n=1). Patients with myeloid malignancy had a median age of 62 at axi-cel apheresis (IQR 56-67), 64% were male and median lines of prior therapy was 4 (IQR 3-6), including 36% with a prior autologous stem cell transplant. Eleven patients were in remission from lymphoma at myeloid malignancy diagnosis, while 3 were diagnosed after progression and interval therapy. Conclusion: This multi-center retrospective study showed similar long-term results to the ZUMA-1 trial, despite including patients who did not meet ZUMA-1 eligibility criteria ba ed on comorbidities. Sixteen percent of PFS events were seen after 1 year, largely due to disease progression. Late infection was common but was not explained by persistent neutropenia or low CD4 counts. Subsequent malignancy, including MDS, occurred in 8% of patients and require further study to better identify patients at risk. (Figure Presented).

Optimizing Commercial Manufacturing of Tisagenlecleucel for Patients in the US: A 4-Year Experiential Journey

Background: Tisagenlecleucel (Kymriah) is an autologous CD19-directed CAR-T-cell therapy, approved in Aug-2017 for treating children and young adults with relapsed/refractory (r/r) acute lymphoblastic leukemia and in May-2018 for treating adults with r/r diffuse large B-cell lymphoma. Post-approval, a key goal has been to upscale and continuously improve manufacturing success and turnaround time in the commercial settings to meet the needs of a global patient population. Here we report accrued experience from our 4-year journey of optimizing the commercial tisagenlecleucel manufacturing process at the US site (Morris Plains, NJ), for faster and successful delivery to patients in the US. Methods: As reported previously, the tisagenlecleucel manufacturing process includes leukapheresis of the patient's peripheral blood mononuclear cells, enrichment and activation of T cells, transduction of the lentiviral vector containing the anti-CD19 CAR transgene, activation with anti-CD3/CD28 antibody-coated beads, expansion in cell culture, washing, and formulation of the viable cells into a cryoformulation medium. The final product is then cryopreserved, shipped back to the treatment center and infused to patients (Tyagarajan, 2020). Use of cryopreserved leukapheresis material as the starting point in commercial manufacturing is unique to tisagenlecleucel;this allows flexibility in terms of scheduling leukapheresis when a patient's health is optimal to provide T cells, and also helps offset logistical challenges (Tyagarajan, 2019). Results: As of Jun-2021, tisagenlecleucel has been manufactured for >5000 patients worldwide, enabled by Novartis's significantly increased global manufacturing footprint at six sites strategically located across six countries (US, France, Switzerland, Germany, Japan and Australia) and a global treatment network of >340 certified centers, including 127 centers in the US. Specifically for the US manufacturing site, between Dec-2020 and Jun-2021, 376 patients in the US had starting material available for manufacturing. Overall, the manufactured product was available for shipment for 98% of patients (shipping success rate [SSR]). The commercial manufacturing success rate (MSR) was 96%, with an out-of-specification (OOS) rate of <3% and no OOS for viability. All ten OOS batches were released for infusion as benefit:risk assessment was positive. Manufacturing was cancelled for two patients upon physician's request. Immediate manufacturing capability without waiting time was available on receipt of all apheresis starting materials. The median time from start of manufacturing to shipping was 20 days. As is evident, the COVID-19 pandemic did not appear to have significantly affected the success rate or manufacturing turnaround time. These latest success metrics, reflecting significant improvements from 2018 to 2021 in MSR (69% to 96%), SSR (93% to 98%), and overall OOS rate (26% to 2%) including viability OOS rate (from 25% to 0%), are a result of upscaling the manufacturing capabilities, enhancements with hospitals focusing on optimizing apheresis collection and cryopreservation procedures, and continuous evaluation and improvement of the manufacturing process since tisagenlecleucel was first launched (Figure). Two key process and analytical improvements that were considered to have improved robustness of manufacturing and testing processes, reduced OOS rates, and minimized variability in turnaround time were introduced towards the end of 2020. Firstly, a simplified sample preparation procedure for final product cell count and viability measurement, which is more reflective of final product at infusion. Secondly, an alternate serum source (5% plasma-derived human AB serum [PD hABs]) which further improves process robustness with a trend towards improved growth and higher peak cell counts. Conclusions: Tisagenlecleucel's current global commercial manufacturing footprint and treatment network are well-positioned to meet anticipated future increase in demand for CAR-T therapies. Recent process improvements h ve significantly increased the MSR (to 96%) and SSR (to 98%), and immediate product availability for patients in need of CAR-T cells. Ongoing and upcoming process improvements are anticipated to further reduce the throughput time, thus allowing more patients faster access to CAR-T therapy. [Formula presented] Disclosures: Rodrigues: Novartis: Current Employment. Duran: Novartis: Current Employment. Eschgfaeller: Novartis: Current Employment. Kuzan: Novartis: Current Employment. Habucky: Novartis: Current Employment.

Primary Analysis of ZUMA-12: A Phase 2 Study of Axicabtagene Ciloleucel (Axi-Cel) As First-Line Therapy in Patients with High-Risk Large B-Cell Lymphoma (LBCL)

Background: High-risk LBCL is associated with poor prognosis after first-line anti-CD20 mAb-containing regimens, highlighting the need for novel treatments. Axi-cel, an autologous anti-CD19 chimeric antigen receptor (CAR) T-cell therapy, is approved for treatment of relapsed/refractory (R/R) LBCL after ≥2 lines of systemic therapy. Here we report the primary analysis of ZUMA-12, a Phase 2, multicenter, single-arm study of axi-cel as part of first-line therapy in patients with high-risk LBCL. Methods: Eligible adults had high-risk LBCL, defined by histology (double- or triple-hit status [MYC and BCL2 and/or BCL6 translocations] per investigator) or an IPI score ≥3, plus a positive interim PET per Lugano Classification (Deauville score [DS] 4/5) after 2 cycles of an anti-CD20 mAb and anthracycline-containing regimen. Patients underwent leukapheresis and received conditioning chemotherapy (cyclophosphamide and fludarabine) followed by a single axi-cel infusion at 2×10 6 CAR T cells/kg. Non-chemotherapy bridging could be administered before conditioning per investigator discretion. The primary endpoint was investigator-assessed complete response (CR) rate per Lugano. Secondary endpoints included objective response rate (ORR;CR + partial response), duration of response (DOR), event-free survival (EFS), progression-free survival (PFS), overall survival (OS), incidence of adverse events (AEs), and levels of CAR T cells in blood and cytokines in serum. The primary analysis occurred after all treated patients had ≥6 months of follow-up. Results: As of May 17, 2021, 42 patients were enrolled and 40 were treated with axi-cel. Median age was 61 years (range, 23-86);68% of patients were male, 63% had ECOG 1, 95% had stage III/IV disease, 48% had DS4, 53% had DS5, 25% had double- or triple-hit status per central assessment, and 78% had IPI score ≥3. A total of 37 patients had centrally confirmed double- or triple-hit histology or an IPI score ≥3 and were evaluable for response, with 15.9 months of median follow-up (range, 6.0-26.7). The CR rate was 78% (n=29;95% CI, 62-90);89% of patients had an objective response, and median time to initial response was 1 month. Among all 40 treated patients, 90% had an objective response (80% CR rate). At data cutoff, 73% of response-evaluable patients had ongoing responses. Medians for DOR, EFS, and PFS were not reached;12-month estimates were 81%, 73%, and 75%, respectively. The estimated OS at 12 months was 91%. All 40 treated patients had AEs of any grade;85% of patients had Grade ≥3 AEs, most commonly cytopenias (68%). Grade ≥3 cytokine release syndrome (CRS) and neurologic events (NEs) occurred in 3 patients (8%) and 9 patients (23%), respectively. Median times to onset of CRS and NEs were 4 days (range, 1-10) and 9 days (range, 2-44), with median durations of 6 days and 7 days, respectively. All CRS and most NEs (28/29) of any grade resolved by data cutoff (1 ongoing Grade 1 tremor);39/40 CRS events resolved by 14 days post-infusion and 19/29 NEs resolved by 21 days post-infusion. Tocilizumab was administered to 63% and 3% of patients for management of CRS or NEs, respectively;corticosteroids were administered to 35% and 33% of patients for CRS and NE management. One Grade 5 event of COVID-19 occurred (Day 350). Median peak CAR T-cell level in all treated patients was 36 cells/µL (range, 7-560), and median expansion by AUC 0-28 was 495 cells/µL × days (range, 74-4288). CAR T-cell levels peaked at a median of 8 days post-infusion (range, 8-37). Higher frequency of CCR7+CD45RA+ T cells in axi-cel product, previously associated with greater expansion of CAR T cells (Locke et al. Blood Adv. 2020), was observed in ZUMA-12, compared with the ZUMA-1 study in R/R LBCL (Neelapu et al. New Engl J Med. 2017). Conclusion: In the primary analysis of ZUMA-12, axi-cel demonstrated a high rate of rapid and complete responses in patients with high-risk LBCL, a population with high unmet need. With 15.9 months of median follow-up, responses were durable as medians for DOR, EFS, nd PFS were not yet reached and over 70% of patients remained in response at data cutoff. No new safety signals were reported with axi-cel in an earlier line. Overall, axi-cel may benefit patients exposed to fewer prior therapies, and further trials in first-line high-risk LBCL are warranted to assess axi-cel in this setting. [Formula presented] Disclosures: Neelapu: Kite, a Gilead Company, Merck, Bristol Myers Squibb, Novartis, Celgene, Pfizer, Allogene, Kuur, Incyte, Precision BioSciences, Legend, Adicet Bio, Calibr, and Unum Therapeutics: Other: personal fees;Kite, a Gilead Company, Bristol Myers Squibb, Merck, Poseida, Cellectis, Celgene, Karus Therapeutics, Unum Therapeutics (Cogent Biosciences), Allogene, Precision BioSciences, Acerta and Adicet Bio: Research Funding;Takeda Pharmaceuticals and related to cell therapy: Patents & Royalties;Kite, a Gilead Company, Merck, Bristol Myers Squibb, Novartis, Celgene, Pfizer, Allogene Therapeutics, Cell Medica/Kuur, Incyte, Precision Biosciences, Legend Biotech, Adicet Bio, Calibr, Unum Therapeutics and Bluebird Bio: Honoraria. Dickinson: Janssen: Consultancy, Honoraria;Takeda: Research Funding;Novartis: Consultancy, Honoraria, Research Funding, Speakers Bureau;Amgen: Honoraria;Celgene: Research Funding;Bristol-Myers Squibb: Consultancy, Honoraria;MSD: Consultancy, Honoraria, Research Funding, Speakers Bureau;Roche: Consultancy, Honoraria, Other: travel, accommodation, expenses, Research Funding, Speakers Bureau;Gilead Sciences: Consultancy, Honoraria, Speakers Bureau. Munoz: Kite, a Gilead Company, Kyowa, Bayer, Pharmacyclics/Janssen, Seagen, Acrotech/Aurobindo, Beigene, Verastem, AstraZeneca, Celgene/BMS, Genentech/Roche.: Speakers Bureau;Bayer, Gilead/Kite Pharma, Celgene, Merck, Portola, Incyte, Genentech, Pharmacyclics, Seattle Genetics, Janssen, and Millennium: Research Funding;Pharmacyclics/Abbvie, Bayer, Kite, a Gilead Company, Pfizer, Janssen, Juno/Celgene, Bristol Myers Squibb, Kyowa Kirin, Alexion, Fosun Kite, Innovent, Seagen, BeiGene, Debiopharm, Epizyme, Karyopharm, ADC Therapeutics, Servier, and Genmab: Consultancy, Other: advisory role;Alexion, AstraZeneca Rare Disease: Other: Study investigator;Targeted Oncology, OncView, Kyowa Kirin, Physicians' Education Resource, and Seagen: Honoraria. Thieblemont: Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses;Gilead Sciences: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses;Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees;Kyte: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses;Bristol Myers Squibb/Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses;Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees;Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses, Research Funding;Incyte: Honoraria, Membership on an entity's Board of Directors or advisory committees;Abbvie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses;Cellectis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses;Hospira: Research Funding;Bayer: Honoraria;Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses. Oluwole: Pfizer: Consultancy;Curio Science: Consultancy;Janssen: Consultancy;Kite, a Gilead Company: Consultancy, Research Funding. Herrera: Takeda: Consultancy;Genentech: Consultancy, Research Funding;Merck: Consultancy, Research Funding;Seagen: Consultancy, Research Fundi g;AstraZeneca: Consultancy, Research Funding;Kite, a Gilead Company: Research Funding;Gilead Sciences: Research Funding;Tubulis: Consultancy;ADC Therapeutics: Consultancy, Research Funding;Bristol Myers Squibb: Consultancy, Research Funding;Karyopharm: Consultancy. Ujjani: Loxo: Research Funding;AstraZeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding;Epizyme: Consultancy, Membership on an entity's Board of Directors or advisory committees;Janssen: Consultancy;TG Therapeutics: Honoraria;Gilead: Honoraria;ACDT: Honoraria;Kite, a Gilead Company: Honoraria;Adaptive Biotechnologies: Research Funding;Atara Bio: Consultancy;AbbVie: Consultancy, Research Funding;Pharmacyclics: Consultancy, Research Funding. Lin: Sorrento: Consultancy;Legend: Consultancy;Novartis: Consultancy;Bluebird Bio: Consultancy, Research Funding;Gamida Cell: Consultancy;Janssen: Consultancy, Research Funding;Celgene: Consultancy, Research Funding;Juno: Consultancy;Vineti: Consultancy;Takeda: Research Funding;Merck: Research Funding;Kite, a Gilead Company: Consultancy, Research Funding. Riedell: Bayer: Honoraria;Karyopharm Therapeutics: Consultancy, Honoraria;Morphosys: Research Funding;Celgene/Bristol-Myers Squibb Company: Consultancy, Honoraria, Research Funding;Verastem Oncology: Honoraria;Kite, a Gilead Company: Honoraria, Research Funding, Speakers Bureau;Novartis: Consultancy, Honoraria, Research Funding;Takeda: Consultancy;BeiGene: Consultancy;Calibr: Research Funding;Xencor: Research Funding;Tessa Therapeutics: Research Funding. Kekre: Gilead: Consultancy, Honoraria;Novartis: Consultancy, Honoraria;Celgene: Consultancy, Honoraria. Lui: Gilead Sciences: Other: stock or other ownership;Kite, a Gilead Company: Current Employment, Other: travel support. Milletti: Kite, aGilead company: Current Employment;Gilead Sciences: Other: stock or other ownership. Dong: Kite, a Gilead Company: Current Employment;Gilead Sciences: Other: stock or other ownership;GliaCure/Tufts: Consultancy, Other: advisory role, Patents & Royalties. Xu: Kite, A Gilead Company: Current Employment;Gilead Sciences: Other: stock or other ownership. Chavez: MorphoSys, Bayer, Karyopharm, Kite, a Gilead Company, Novartis, Janssen, AbbVie, TeneoBio, and Pfizer: Consultancy;ADC Therapeutics: Consultancy, Research Funding;Merk: Research Funding;AstraZeneca: Research Funding;MorphoSys, AstraZeneca, BeiGene, Genentech, Kite, a Gilead Company, and Epizyme: Speakers Bureau;BMS: Speakers Bureau.

Analysis of Outcomes and Predictors of Response in Patients with Relapsed Mantle Cell Lymphoma Treated with Brexucabtagene Autoleucel

Background: Brexucabtagene autoleucel (brexu-cel) is the first CD19 chimeric antigen receptor T-cell (CAR T) therapy approved for use in patients (pts) with relapsed mantle cell lymphoma (MCL). The ZUMA-2 trial demonstrated that brexu-cel induces durable remissions in these pts with an ORR of 85% (59% CR), estimated 12-month PFS rate of 61%, and similar toxicity profile to other CAR T therapies (Wang et al, NEJM 2020). We conducted a multicenter, retrospective study of pts treated with commercial brexu-cel to evaluate its safety and efficacy in the non-trial setting. Methods: We reviewed records of pts with relapsed MCL across 12 US academic medical centers. Pts who underwent leukapheresis between July 2020 and June 2021 with the intent to proceed to commercial brexu-cel were included. Baseline demographic and clinical characteristics were summarized using descriptive statistics. Survival curves were generated using the Kaplan-Meier method, and univariate models were fit to identify predictors of post-CAR T outcomes. Results: Fifty-five pts underwent leukapheresis. There were 3 manufacturing failures. Baseline characteristics of the 52 pts who received brexu-cel are summarized in Table 1. Median age was 66 yrs (range: 47-79 yrs) and 82% were male. Twenty of 29 (69%) pts with known baseline MIPI were intermediate or high risk. Seven pts had a history of CNS involvement. The median number of prior therapies was 3 (range: 2-8), including prior autologous stem cell transplant (ASCT) in 21 (40%) and prior allogeneic transplant in 2 pts (1 with prior ASCT and 1 without). Fifty percent had relapsed within 24 months of their initial therapy. All pts had previously received a Bruton's tyrosine kinase inhibitor (BTKi), including 29 (56%) with disease progression on a BTKi. Forty (77%) pts received bridging therapy (17 BTKi, 10 BTKi + venetoclax, 6 chemo, 3 venetoclax, 2 XRT only, 1 steroids only, 1 lenalidomide + rituximab). The ORR was 88% (CR 69%) among patients who received brexu-cel. Two pts had PD on initial restaging and 3 died prior to first response assessment (without evidence of relapse). Seven pts have not completed restaging due to limited follow-up (< 3 months) and were not included in the response assessment. Five pts have progressed, including 2 with CR and 1 with PR on initial restaging. With a median follow-up of 4.2 months, the estimated 6-month PFS and OS rates were 82.7% and 89.0%, respectively. All 7 pts with prior CNS involvement were alive without relapse at last follow-up. The incidence of cytokine release syndrome (CRS) was 84% (10% grade ≥ 3) with a median time to max grade of 5 days (range: 0-10 days). There were no cases of grade 5 CRS. The incidence of neurotoxicity (NT) was 57% (31% grade ≥ 3) with a median time to onset of 7 days (range: 4-15 days). NT occurred in 4/7 pts with prior CNS involvement (3 grade 3, 1 grade 4). Grade 5 NT occurred in 1 pt who developed cerebral edema and died 8 days after infusion. Thirty-five pts received tocilizumab, 33 received steroids, 7 received anakinra, and 1 received siltuximab for management of CRS and/or NT. Post-CAR T infections occurred in 8 pts, including two grade 5 infectious AEs (covid19 on day +80 and septic shock on day +40 after infusion). Rates of grade ≥ 3 neutropenia and thrombocytopenia were 38% and 37%, respectively. Among pts with at least 100 days of follow-up and lab data available, 5/34 (15%) had persistent grade ≥ 3 neutropenia and 4/34 (12%) had persistent grade ≥ 3 thrombocytopenia at day +100. Five pts have died, with causes of death being disease progression (2), septic shock (1), NT (1), and covid19 (1). Univariate analysis did not reveal any significant associations between survival and baseline/pre-CAR T MIPI, tumor pathologic or cytogenetic features, prior therapies, receipt of steroids/tocilizumab, or pre-CAR T tumor bulk. Conclusions: This analysis of relapsed MCL pts treated with commercial brexu-cel reveals nearly identical response and toxicity rates compared to those reported on ZUMA-2. Longer follow-up is require to confirm durability of response, but these results corroborate the efficacy of brexu-cel in a population of older adults with high-risk disease features. While all 7 pts with prior CNS involvement are alive and in remission, strategies to mitigate the risk of NT in this setting need to be evaluated. Further studies to define the optimal timing of CAR T, bridging strategies, and salvage therapies for post-CAR T relapse in MCL are warranted. [Formula presented] Disclosures: Gerson: TG Therapeutics: Consultancy;Kite: Consultancy;Abbvie: Consultancy;Pharmacyclics: Consultancy. Sawalha: TG Therapeutics: Consultancy, Research Funding;Celgene/BMS: Research Funding;BeiGene: Research Funding;Epizyme: Consultancy. Bond: Kite/Gilead: Honoraria. Karmali: Janssen/Pharmacyclics: Consultancy;BeiGene: Consultancy, Speakers Bureau;Morphosys: Consultancy, Speakers Bureau;Takeda: Research Funding;Genentech: Consultancy;AstraZeneca: Speakers Bureau;Roche: Consultancy;Karyopharm: Consultancy;Epizyme: Consultancy;Kite, a Gilead Company: Consultancy, Research Funding, Speakers Bureau;BMS/Celgene/Juno: Consultancy, Research Funding;EUSA: Consultancy. Torka: TG Therapeutics: Membership on an entity's Board of Directors or advisory committees. Chow: ADC Therapeutics: Current holder of individual stocks in a privately-held company, Research Funding;AstraZeneca: Research Funding. Shadman: Abbvie, Genentech, AstraZeneca, Sound Biologics, Pharmacyclics, Beigene, Bristol Myers Squibb, Morphosys, TG Therapeutics, Innate Pharma, Kite Pharma, Adaptive Biotechnologies, Epizyme, Eli Lilly, Adaptimmune, Mustang Bio and Atara Biotherapeutics: Consultancy;Mustang Bio, Celgene, Bristol Myers Squibb, Pharmacyclics, Gilead, Genentech, Abbvie, TG Therapeutics, Beigene, AstraZeneca, Sunesis, Atara Biotherapeutics, GenMab: Research Funding. Ghosh: Genentech: Research Funding;Pharmacyclics LLC, an AbbVie Company: Consultancy, Honoraria, Research Funding, Speakers Bureau;Karyopharma: Consultancy, Honoraria;Seattle Genetics: Consultancy, Honoraria, Speakers Bureau;Janssen: Consultancy, Honoraria, Speakers Bureau;TG Therapeutics: Consultancy, Honoraria, Research Funding;Incyte: Consultancy, Honoraria;Gilead: Consultancy, Honoraria, Research Funding, Speakers Bureau;Genmab: Consultancy, Honoraria;Epizyme: Honoraria, Speakers Bureau;Bristol Myers Squibb: Consultancy, Honoraria, Research Funding, Speakers Bureau;AstraZeneca: Consultancy, Honoraria, Speakers Bureau;ADC Therapeutics: Consultancy, Honoraria;Adaptive Biotech: Consultancy, Honoraria;AbbVie: Honoraria, Speakers Bureau. Moyo: Seattle Genetics: Consultancy. Fenske: TG Therapeutics: Consultancy, Speakers Bureau;Servier Pharmaceuticals: Consultancy;Seattle Genetics: Speakers Bureau;Sanofi: Speakers Bureau;Pharmacyclics: Consultancy;MorphoSys: Consultancy;Kite (Gilead): Speakers Bureau;KaryoPharm: Consultancy;CSL Therapeutics: Consultancy;Bristol-Myers Squibb: Speakers Bureau;Biogen: Consultancy;Beigene: Consultancy;AstraZeneca: Speakers Bureau;ADC Therapeutics: Consultancy;Adaptive Biotechnologies: Consultancy;AbbVie: Consultancy. Grover: Genentech: Research Funding;Novartis: Consultancy;ADC: Other: Advisory Board;Kite: Other: Advisory Board;Tessa: Consultancy. Maddocks: Seattle Genetics: Divested equity in a private or publicly-traded company in the past 24 months;BMS: Divested equity in a private or publicly-traded company in the past 24 months;Pharmacyclics: Divested equity in a private or publicly-traded company in the past 24 months;Novatis: Divested equity in a private or publicly-traded company in the past 24 months;Janssen: Divested equity in a private or publicly-traded company in the past 24 months;Morphosys: Divested equity in a private or publicly-traded company in the past 24 months;ADC Therapeutics: Divested equity in a private or publicly-traded company in the past 24 months;Karyopharm: Divested equity in a private or publicly-traded company in the past 24 months;Beigene: Divested equity in a private or publicly-traded company in the past 24 months;Merck: Divested equity in a private or publicly-traded company in the past 24 months;KITE: Divested equity in a private or publicly-traded company in the past 24 months;Celgene: Divested equity in a private or publicly-traded company in the past 24 months. Jacobson: Kite, a Gilead Company: Consultancy, Honoraria, Other: Travel support;Humanigen: Consultancy, Honoraria, Other: Travel support;Celgene: Consultancy, Honoraria, Other: Travel support;Pfizer: Consultancy, Honoraria, Other: Travel support, Research Funding;Lonza: Consultancy, Honoraria, Other: Travel support;AbbVie: Consultancy, Honoraria;Precision Biosciences: Consultancy, Honoraria, Other: Travel support;Novartis Pharmaceuticals Corporation: Consultancy, Honoraria, Other: Travel support;Nkarta: Consultancy, Honoraria;Axis: Speakers Bureau;Clinical Care Options: Speakers Bureau. Cohen: Janssen, Adaptive, Aptitude Health, BeiGene, Cellectar, Adicet, Loxo/Lilly, AStra ZenecaKite/Gilead: Consultancy;Genentech, Takeda, BMS/Celgene, BioInvent, LAM, Astra Zeneca, Novartis, Loxo/Lilly: Research Funding.

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 includ 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. Disclosures: Kenderian: 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.

Hypothesis: Immunotherapy by Selective Convalescent Blood Engineering to Stifle Diseases like COVID-19.

Current standard vaccine testing protocols take approximately 10-24 months of testing before a vaccine can be declared successful. Sometimes by the time a successful vaccine is out for public use, the outbreak may already be over. With no vaccine or antiviral drug available to treat the infected, we are left with the age-old methods of isolation, quarantine, and rest, to arrest such a viral outbreak. Convalescent blood therapy and covalent plasma therapy have often proved effective in reducing mortality, however, the role of innate and adaptive immune cells in these therapies have been overlooked. Antigen presenting cells (APCs), CD4+ T memory cells, CD8+ T memory cells, and memory B-Cells all play a vital role in sustainable defense and subsequent recovery. This report incorporates all these aspects by suggesting a novel treatment therapy called selective convalescent leukapheresis and transfusion (SCLT) and also highlights its potential in vaccination. The anticipated advantages of the proposed technique outweigh the cost, time, and efficiency of other available transfusion and vaccination processes. It is envisioned that in the future this new approach could serve as a rapid emergency response to subdue a pathogen outbreak and to stop it from becoming an epidemic, or pandemic.

Early Leukapheresis Depletion in an Ex-Premature with Severe Acute Respiratory Distress Syndrome Due to Bordetella Pertussis and Coronavirus Infection.

We describe a 2 weeks corrected gestational age infant admitted in pediatric intensive care unit (PICU) for severe acute respiratory distress syndrome (ARDS) associated to Bordetella pertussis and Coronavirus infection. He developed leukocytosis as soon as ARDS required intubation and aggressive mechanical ventilation: hence he underwent 3 early therapeutic leukapheresis treatments in order to avoid the worsening of related cardiopulmonary complications, according to recent literature on pertussis infection in infants. The infant was discharged from PICU healthy.