ALBERT

Description: Background: Lower total CD34+ cell dose and increased HLA-mismatch are known predictors of engraftment failure and higher transplant related mortality (TRM) in cord blood (CB) recipients. To compensate for cell dose, double unit grafts (DUCBT) are commonly used in adult. However, in the majority of patients (pts), only one of the two CB units engrafts. Identification of the factors that predict which unit will engraft remains elusive, although increased recipient-donor HLA-matching and larger CD3+ cell dose have been associated with the predominating unit in a single center retrospective analysis (Ramirez et al, 2012). Historically, CB units are selected by maximizing matching at the HLA-A and -B antigen and -DRB1 allelic level. Evidence supports that matching at HLA-C appears to decrease TRM, and many clinicians incorporate HLA-C antigen matching into unit selection. It is unclear, however, if HLA-C matching predicts the engrafting unit in DUCBT. This study retrospective study evaluates whether HLA-C matching is associated with the winning CB unit. Design: Clinical data was reviewed from all pts with a hematologic malignancy receiving a DUCBT at Moffitt Cancer Center between November 13, 2009 and August 29, 2013. Chimerism studies identified the predominating unit (〉 65% single unit) between day 21 and day 28. Subsequent chimerism analyses performed at a median of day 100 confirmed unit predominance. Unit selection required intermediate resolution antigen match at HLA-A, -B, -C, and high resolution allele match at -DRB1. Units were a minimum of 4/8 matched to the patient and each other with a minimum cell dose of 1.5 x 107 total nucleated cell dose (TNC) /kg. Serology for donor specific antibodies against both units was negative. Results: Excluding 6 pts who were missing HLA-C typing on one or both CB units, 54 pts with hematologic malignancies (ALL=6, MDS/AML=29, Other=19) received chemotherapy and total body irradiation as part of a myeloablative conditioning (MAC) or reduced intensity conditioning (RIC) with or without thymoglobulin (ATG) followed by a DUCBT (MAC=14, RIC=23, RIC+ATG=17). Median age was 52 (range 22-69) years. Seven pts demonstrated persistent mixed chimerism in the myeloid and/or lymphoid cell lines beyond day 100. A total of 20 pts with available chimerism data received at least one CB unit matched to the recipient at HLA-C, with one patient excluded due to persistent mixed chimerism. Six pts received both CB units matched at HLA-C, but of the 13 pts receiving one matched and one mismatched unit, the HLA-C matched unit was the engrafting unit 69% (9/13) of the time. Comparing similar HLA mispairings, a matched unit engrafted over a mis-matched unit at HLA-A 50% (5/10) of the time, at HLA-B 38% (5/13) of the time, and at HLA-DRB1 50% (3/6) of the time. TNC dose (larger vs smaller with a required difference of at least 0.03 x 107 TNC/kg), order of infusion (first vs second unit), and overall CB unit HLA matching (4/8-8/8), were assessed as potential predictors for engraftment. Of evaluable patients, the CB unit with the larger TNC engrafted 44% (16/36) of the time, and the first unit infused was the engrafting unit 54% (21/39) of the time. In patients with an unequal overall match grade between the CB units, the better HLA-matched CB unit engrafted 64% (14/22) of the time. Survival analysis of all pts revealed that those who received at least one CB unit antigen matched at HLA-C (n=20) had a 100 day and 1 year overall survival (OS) of 85% (95% Confidence Interval(CI): 67–97%) and 55% (95% CI: 33–75), respectively, whereas pts receiving two HLA-C mismatched CB units (n=34), 100 day OS was 62% (95% CI: 45–77) with 1 year OS 44% (95% CI: 28–61) (Fig 1). Conclusion: HLA-C antigen matching appears to help predict the winning unit in settings of HLA-match disparity and DUCBT. Confirmation in a larger population of DUCBT recipients is necessary. To date, the effects of HLA matching and other variables influencing engraftment have been predominately evaluated in recipients of single unit transplants and studies in DUCBT have been limited. Further investigation assessing HLA matching as well as donor-donor interactions is best served through a multicenter data resource. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

Description: Introduction: Approximately 60% of Large B cell Lymphoma (LBCL) patients that receive CD19 CAR T cell therapy with axicabtagene ciloleucel (axi-cel) experience lymphoma progression (Locke et al. Lancet Oncol. 2019) and the likelihood of response to subsequent therapy is low (Spiegel, Dahiya et al. ASCO 2019). Target loss of CD19 is observed in less than a third of patients experiencing relapse. Alternative mechanisms of resistance to axi-cel are poorly understood. Lymphoma patients with elevated serum markers of systemic inflammation, such as ferritin and IL-6, have worse outcomes following axi-cel (Locke, Neelapu et al. Mol.Ther.2017; Faramand et al. ASH 2018). We hypothesized that suppressive monocytic myeloid derived suppressor cells (M-MDSCs), which are associated with worse chemotherapy outcomes in LBCL (Azzaoui et al. Blood 2016), and tumor driven inflammation may be present and responsible for decreased efficacy of axi-cel in LBCL. Methods: LBCL patients undergoing axi-cel treatment were enrolled onto prospective sample collection protocols. Patients were stratified for analysis into ongoing responders (complete response or partial response) or relapsed (progressive disease) after a minimum of 3 months follow-up (range 3 - 15 months). M-MDSCs, defined as a Lin-, CD11b+, CD33+, CD15-, CD14+, HLA-DRlow population, were sorted from leftover apheresis material after collection for axi-cel manufacture. M-MDSC ability to suppress proliferation of autologous T cells stimulated with CD3/CD28 coated beads was measured by 3H thymidine incorporation. Circulating peripheral blood M-MDSCs, quantified by % of live cells by flow cytometry, were measured at the time of apheresis and serially after axi-cel infusion until day 30. In vitro mouse experiments utilized a CD19-CD28 CAR and cytokine-induced bone marrow MDSCs (Thevenot et al. Immunity 2014). Cytokines were measured by ELISA and cytotoxicity against CD19 bearing cell lines used xCELLigence real-time cell analysis, as we have done previously (Li et al. JCI Insight 2018).Tumor biopsies were taken within 1 month prior to infusion of axi-cel. Limited gene expression profiling of tumor microenvironment (TME) genes used the Nanostring IO360 panel (770 genes). Analysis used nSolver to identify cell types, GSEA and differential gene expression between groups. Results: First, we demonstrated that M-MDSCs sorted from patient apheresis material suppressed the proliferation of autologous T cells (n=6). We next enumerated M-MDSCs in the peripheral blood (n = 32). M-MDSC numbers initially decreased after lymphodepleting chemotherapy but recovered to baseline levels by day +10. The level of M-MDSCs following CAR T cell therapy strongly correlated with pre-CAR T baseline levels (R = 0.871, p

Description: Graft-versus-host disease (GVHD) remains the principal obstacle to achieve successful outcomes in allogeneic hematopoietic stem cell transplant (HCT). Glucocorticoids are the current standard initial treatment for acute GVHD with complete responses of 25% to 41%. New immunosuppressive strategies are required to improve management of acute GVHD and decrease toxicities of immunosuppressive agents. We conclude that more effective acute GVHD therapy might improve remission rates that will result in better survival after allogeneic HCT. Vorinostast, a histone deacetylase inhibitor (HDACi) have shown efficacy for acute GVHD prevention. This protocol was design to test the safety and potential efficacy of a novel HDACi, panobinostat (LBH589), administered to patients with acute GVHD within 72 hours of initiation of glucocorticoid therapy (methylprednisolone 0.8 mg/Kg/day IV or equivalent for at least 14 days) as first line therapy. Panobinostat is a potent inhibitor of deacetylases and HSP90 belonging to a structurally novel class of the cinnamic hydroxamic acid class of compounds and is one of most potent HDAC inhibitors. We have enrolled n=13 subjects, median age 52 (range, 39-63) years, male n=8/female n=5, median day of GVHD development day + 37 post HCT (26 -528 days) with overall grade GVHD II (n=8) or III (n=5). The first three patients were treated with 2.5MG/M2 intravenously (IV) weekly x 4 and subsequent subject was treated with 5MG/M2 IV weekly x 4 achieving all GVHD CR by day +15. Patients were treated with azole for fungal prophylaxis. Due to manufacturer discontinuation of IV formulation production we were obliged to amend the protocol to use PO Panobinostat. Using 10MG PO TIW 3 doses q week x 4 weeks, we treated 2 subjects which were both discontinued from study drug as evidence of GHVD progression within 7 days of Panobinostat. Due to safety concerns, the next group was treated with a reduce dose of 5 MG PO TIW q week x 4 (Level -1). So far we have accrued 7 subjects whom by day 15 achieved GVHD CR (n:4) and PR (n:3) majority being in CR (n:6/7) on day +28 and PR (n:1). Toxicities by CTCAE 4.0 criteria included reversible thrombocytopenia and neutropenia grade 1-2 possible related to study drug. We are encouraged with a GVHD CR rate of 57% on day +15 and 86% CR at study drug completion on day+36. These results suggest a role HDACi Panobinostat as a tool to improve success of glucocorticoids for GVHD treatment. Correlative studies are planned to address pharmacodynamics of Panobinostat on inflammatory cytokines, to correlate DAC enzymatic activity inhibition and clinical response and to proteins/histones acetylation in T-cell subsets. Disclosures: No relevant conflicts of interest to declare.

Description: Introduction: Gastro-intestinal GVHD (GI GVHD) is a common and severe complication of allogeneic hematopoietic cell transplantation (HCT). Systemic glucocorticoids remain the standard of care for GI GVHD, despite their incomplete efficacy and toxicity. Steroid-sparing activity and improved survival were reported with oral administration of poorly absorbed beclomethasone dipropionate (BDP) in combination with systemic glucocorticoids for upper GI GVHD, and promising results were described with the adjunct of budesonide (BUD) for lower GI GVHD. No data have been reported on BDP or BUD without systemic glucocorticoids. Our team has adopted the practice of administering BDP/BUD without systemic glucocorticoids as fist-line therapy. Here we assess safety and efficacy of our practice in the treatment of isolated GI GVHD. Methods: We analyzed retrospective data from 297 consecutive patients (pts) with isolated GI GVHD after hematopoietic peripheral blood stem cell transplantation performed at the Moffitt Cancer Center between July 2004 and June 2013. At discretion of the treating physician, patients with upper with or without lower GI GVHD were treated with BDP (5 mg BID or TID orally), BDP plus prednisone (PRED 0.5-2 mg/kg or equivalent glucocorticoid dose), BDP+BUD (3 mg BID or TID orally) or BDP+BUD+PRED. The primary study endpoint was response of GI GVHD after 28 days, defined as complete resolution of all GI symptoms without addition of other immune suppressive (IS) agent(s) or partial reduction of GI symptoms, without resolution and without addition of other IS agent(s). Secondary endpoints were response to treatment after 200 days, chronic GVHD (CGVHD), CMV infection, relapse free survival (RFS), and overall survival (OS). All endpoints were analyzed according to treatment arm (Figure 1). A multivariable model was used to test the association between response after 28 days and treatment arm, after adjusting for primary diagnosis, conditioning regimen, disease status at HCT, pts/donor characteristics, GI GVHD overall grade, GI GVHD site, and albumin level. Results: BDP vs. BDP+PRED. Baseline characteristics were well balanced among the BDP (n=90) and BDP+PRED (n=24) groups, including treatment for isolated upper GI GVHD (84% vs. 67%, p=0.08), with the remainder affected by both upper and lower GI GVHD. BDP+PRED showed a significantly higher response of GI GVHD after 28 days compared to BDP (88% vs. 56%, multivariate OR 23, 95% CI 3-161, p=0.002); however there was no significant difference in response after 200 days (50% vs. 33%, univariate p=0.5). There were no significant differences in terms of treatment duration, requirement of additional IS agents, CMV reactivation, CGVHD development, RFS and OS between the two treatment cohorts. BDP+BUD vs. BDP+BUD+PRED. BDP+BUD+PRED pts (n=53) had more rapid onset of GI GVHD (median 20 vs. 26 days after HCT, p=0.001), higher incidence of lower GI involvement (61% vs. 38%, p=0.008) and higher incidence lower GI stage II-III GVHD (p=0.0004) compared to BDP+BUD pts (n=130). Despite adjusting for these higher risk features by multivariable analyses, BDP+BUD+PRED was associated with a significantly higher response after 28 (90% vs. 75%, multivariate OR 15, 95% CI 3-62, p=0.0003) and 200 days (70% vs. 45%, univariate p=0.0003). There were no significant differences in treatment duration, CMV reactivation, CGVHD development, RFS and OS between the two treatment cohorts. Conclusions: This retrospective analysis suggests that the addition of systemic PRED to topical BDP/BUD therapy for isolated GI GVHD was associated with a better response after 28 days of treatment. Despite the inferiority in GI GVHD response, there were no differences in secondary endpoints including treatment duration, CMV reactivation, RFS and OS. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

Description: Introduction: Autologous anti-CD19 chimeric antigen receptor (CAR) T-cell therapy achieves rapid and durable responses in patients with r/r DLBCL, although unique potential toxicities require specialized management. Cytokine release syndrome (CRS) is the most commonly observed adverse event of special interest associated with CAR T-cell therapy. Two CRS grading scales have been used in different clinical trials of CAR T-cell therapy: the Penn scale (Porter, Sci Transl Med, 2015; Porter, J Hematol & Oncol, 2018) and the Lee scale (Lee, Blood, 2014; Neelapu, Nat Rev Clin Oncol, 2017). To better inform management of CRS and develop best practices, we assessed concordance and differences between the two scales by using the Lee scale to regrade observed CRS events in r/r DLBCL patients treated with tisagenlecleucel, who were previously graded per protocol using the Penn scale. Methods: Individual patient level data from the JULIET trial, a single-arm, open-label, multicenter, global phase 2 trial of tisagenlecleucel in adult patients with r/r DLBCL (NCT02445248), were used in this study. Four medical experts who had managed DLBCL patients using different CAR T-cell therapy protocols and products independently reviewed the data, while blinded to the original Penn grading, and re-graded CRS for JULIET patients using the Lee scale. Re-grading assessments and disagreements in the assigned Lee grade were discussed and reconciled among reviewers during a live meeting. As per the investigational charter, the most conservative final assessment of any expert reviewer determined the final grading for any individual case. For example, if an event was graded as 2, 3, 3 and 4, then grade 4 would be the final grading. Results: As of December. 8, 2017, 111 patients with r/r DLBCL were infused with tisagenlecleucel in the JULIET trial. Sixty-four (58%) patients had CRS graded according to the Penn scale and each case was re-graded using the Lee scale based on JULIET data collected prospectively (e.g., CRS-related symptoms, oxygen supplementation, intervention for hypotension, and organ toxicities). Using the Lee scale, 63 (57%) patients were considered to have any grade CRS by investigators, including grade 1 events in 26 (23%), grade 2 in 18 (16%), grade 3 in 10 (9%), and grade 4 in 9 (8%) (Figure 1). One patient with grade 1 per Penn scale was re-graded to grade 0 due to absence of documented fever or symptoms requiring intervention. Compared to Penn grades, the Lee scale provided the same grade for 39 patients, a lower grade for 20 patients, and a higher grade for 5 patients. Among 64 patients re-graded, 59 (92%) had fever, 27 (42%) had oxygen supplementation (3 with grade 1, 6 grade 2, 9 grade 3, and 9 grade 4 per Lee scale) and 7 (11%) had concurrent infections. Of 29 (45%) patients requiring intervention for hypotension (13 with grade 2, 7 grade 3, and 9 grade 4 per Lee scale), 28 had fluid resuscitation and 10 received high dose/combination vasopressors. In addition, 8 of 9 patients re-graded as Lee grade 4 were intubated. As for anti-cytokine therapy, only 17 patients received tocilizumab (1 for grade 1, 2 for grade 2, 5 for grade 3, and 9 for grade 4 CRS per Lee scale) and 12 patients received corticosteroids (2 for grade 2, 1 for grade 3, and 9 for grade 4 CRS per Lee scale). Conclusions: Different CAR-T studies in DLBCL patients have used different approaches (Lee and Penn scales) for grading CRS and had different thresholds for tocilizumab treatment of CRS. Harmonization of grading CRS between studies permits a more accurate comparison of observations and outcomes. In this analysis, patients with r/r DLBCL receiving tisagenlecleucel in the JULIET trial, which used the Penn scale to grade CRS, were re-graded by expert consensus using the Lee scale. Using the Lee scale, more patients were categorized as grade 1 (Lee vs. Penn: 26 vs. 17), fewer patients as grades 2 and 3 (18 vs. 23, and 10 vs. 15, respectively), and the same number of patients as grade 4 (9 vs. 9) compared to the Penn scale. The re-grading of the JULIET CRS data using the Lee scale makes it possible to perform comparative analyses of CRS outcomes from clinical trials using different CAR-T products and could be used to develop best practice guidelines. Disclosures Schuster: Pfizer: Membership on an entity's Board of Directors or advisory committees; Nordic Nanovector: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Dava Oncology: Consultancy, Honoraria; Merck: Consultancy, Honoraria, Research Funding; OncLive: Honoraria; Genentech: Honoraria, Research Funding; Gilead: Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Physician's Education Source, LLC: Honoraria; Novartis Pharmaceuticals Corporation: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Maziarz:Athersys, Inc.: Patents & Royalties; Kite Therapeutics: Honoraria; Juno Therapeutics: Consultancy, Honoraria; Incyte: Consultancy, Honoraria; Novartis Pharmaceuticals Corporation: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Ericson:Novartis Pharmaceuticals Corporation: Employment. Rusch:Novartis Pharmaceuticals Corporation: Employment. Romanov:Novartis Pharmaceuticals Corporation: Employment. Locke:Cellular BioMedicine Group Inc.: Consultancy; Novartis Pharmaceuticals: Other: Scientific Advisor; Kite Pharma: Other: Scientific Advisor. Maloney:Janssen Scientific Affairs: Honoraria; Roche/Genentech: Honoraria; Seattle Genetics: Honoraria; GlaxoSmithKline: Research Funding; Juno Therapeutics: Research Funding.

Description: Introduction: One of the main complications of adoptive T cell therapy (ACT) is the en-masse activation of tumor-reactive T cells inducing a large release of cytokines followed by activation of other immune cells leading to adverse events. These are classified as a cytokine release syndrome (CRS) or neurotoxicity described as a CAR T Related Encephalopathy Syndrome (CRES). Several biomarkers have been associated with CRS and/or neurotoxicity such as LDH, ferritin and CRP. Cytokines have also been associated with CRS and and/or CRES, but present approaches rely on retrospective study of collected biomarkers. Here, we report the results of cytokine analysis using a point of care (POC) device to predict immune-related toxicities in patients with relapsed/refractory (R/R)DLBCL treated with axicabtagene ciloleucel (axi-cel). Methods: Patients with R/R DLBCL treated with commercial axi-cel were included in this study. Baseline serum samples were collected prior to lymphodepleting chemotherapy and then daily during hospitalization. To select which cytokines to monitor, we retrospectively analyzed 38 serum cytokines in a cohort of 53 patients with R/R B cell acute lymphoblastic leukemia (B-ALL) who were treated with 19-28z CAR T cells. The patients were divided into those requiring treatment with tocilizumab and/or steroids versus those who did not require treatment. We observed several cytokines, including IL-2, IL-6, IL-15 and IFNg, which were significantly elevated in patients with CRS and/or CRES requiring treatment (Figure 1a). Based on this analysis and results of published studies, eight serum proteins were selected in our study including IL-1b, IL-2, IL-6, IL-15, IFNg, TNFa, and angiopoietin-1 &2. We monitored these proteins using a POC device that allows for rapid daily monitoring with a turnaround time of two hours. We established that the results from the POC device strongly correlate with a current gold standard device(Luminex), which has a typical two day turn around time. CRS and CRES were prospectively graded using revised Lee criteria (Lee et al Blood 2014) and the CARTOX group (Neelapu et al. NRCO 2017) respectively by an experienced clinical team and confirmed by chart review retrospectively. Results: A total of 20 patients with R/R DLBCL treated with commercial axi-cel were identified. Median age 64 years ( range 43-73) with 80% male.In our cohort, grades 1-3 CRS were observed in 45%, 40% and 5% respectively. There were no observed grade 0 or grade 4 CRS. There were two patients (10%) who died in the setting of severe toxicity. Patients with grade 5 CRS had higher levels of IL-6 and angiopoietin 2/angiopoietin 1 ratio at day one, which correlated with severity of toxicity r=0.52 (p= 0.039) , and r=0.53 (p=0.033) respectively (Fig. 1b). Furthermore, patients with high grades CRS had elevated levels of IL-15 at day seven (r=0.83, p=0.006). The majority of patients (55%) had grade 1-2 CRES.There were no significant correlations between serum cytokine levels and CRES or between those who required tocilizumab/steroids vs. those who did not, likely due to the small sample size. In select cases, daily monitoring of cytokines using the POC device provided clinical insight that wasn't evident from standard biomarkers. For example, one patient who developed delayed CRS had high serum levels of IL-6 but did not have elevated levels of CRP(Fig.1c). Discussion: In this analysis of 20 patients, we observed a correlation between severe CRS and elevated serum cytokine levels of IL-6 and angiopoietin 2/angiopoietin 1 ratio at day one suggesting that these biomarkers may be utilized to predict severe toxicity in patients treated with ACT. While this study is limited by small sample size, our observations correlate with previously published biomarkers data in patients enrolled in clinical trials. To our knowledge this is the first reported cytokine data using commercial axi-cel. Monitoring of cytokines using a POC device is feasible and will be useful clinically. High risk patients may be identified early and help guide intervention in real time, for example day one elevated IL-6 levels might inform earlier use of tocilizumab. We continue to enroll patients to validate cytokines as predictive biomarkers with the goal of informing the development of preventative strategies to mitigate CAR T cell therapy immune related adverse events. Disclosures Locke: Cellular BioMedicine Group Inc.: Consultancy; Kite Pharma: Other: Scientific Advisor; Novartis Pharmaceuticals: Other: Scientific Advisor. Brentjens:Juno Therapeutics, a Celgene Company: Consultancy, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding. Park:Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees; AstraZeneca: Consultancy; Kite Pharma: Consultancy; Juno Therapeutics: Consultancy, Research Funding; Adaptive Biotechnologies: Consultancy; Novartis: Consultancy; Pfizer: Consultancy; Shire: Consultancy. Davila:Celyad: Consultancy, Membership on an entity's Board of Directors or advisory committees.

Description: Introduction: The autologous anti-CD19 chimeric antigen receptor (CAR) T-cell therapy, axicabtagene ciloleucel (Axi-cel) improved long-term survival of patients with relapsed/refractory diffuse large B-cell lymphoma (r/r DLBCL). Long-term analysis of the pivotal ZUMA-1 trial indicates a 2-year PFS of ~40% (Locke, Lancet Oncology 2018). Early identification of patients with increased relapse risk may allow for early intervention and improved outcomes. In a pilot study of 6 ZUMA-1 patients, minimal residual disease (MRD) evaluation via a next-generation sequencing MRD assay (Adaptive Biotechnologies, Seattle, WA) to assess for circulating tumor (ct)DNA, mirrored clinical outcome as assessed by PET-CT (Hossain et. al. Leukemia & Lymphoma 2019). Based on these promising results, a multi-institutional prospective study utilizing cell-free MRD assessments to predict outcomes in r/r DLBCL patients after Axi-cel therapy was initiated. Methods: To identify tumor clonotype(s), tumor DNA extracted from archival paraffin-embedded tissue underwent PCR amplification of IgH-VDJ, IgH-DJ and IgKappa/Lambda regions using universal consensus primers. CtDNA levels were measured pre-LD, 0, 7, 14, 21, 28, 56, 90, 180, 270, and 365 days following Axi-cel infusion. PET-CT scans were obtained at baseline, Day 28, Month 3, 6, and 12 with response assessed per Lugano criteria. Deauville 1-3 was considered PET-negative. The protocol prespecified that patients with less than Day 28 follow-up be excluded from analysis. Any detectable ctDNA was considered MRD positive. Results: Here we report on the pre-planned analysis of the first 50 study patients with at least a Day 28 MRD assessment and 3 months of follow up. An additional 4 patients with at least 3 months of follow-up but who did not have a Day 28 MRD assessment were also included. Baseline characteristics and clinical outcomes of patients were similar to ZUMA-1 and a real-world analysis of 295 patient who received Axi-cel (Nastoupil et al ASH 2018). The median age was 61 years old (range 19-76) (53.7% male, 46.3% female) and 59% of patients received 3 or more prior lines of therapy (range 1-6). After a median follow-up of 7.5 months, the best overall response rate was 87% (47 of 54) and complete response rate was 57% (31 of 54). The median OS was not reached and median PFS was 4.6 months (panel A). At Day 28, 56% (28 of 50) of patients were MRD negative (MRD-neg) and 44% (22 of 50) were MRD positive (MRD-pos). As compared to MRD-pos, MRD-neg correlated with improved median PFS (not reached vs. 2.96 months, p

Description: Background: Fever is a cardinal symptom of cytokine release syndrome (CRS) after CAR T-cell therapy with 84% of patients experiencing fever on the ZUMA-1 trial of axicabtagene ciloleucel (axi-cel). Knowledge of the patterns of fever and associated symptoms may inform the clinical management of these patients. Methods: We performed a single center retrospective study in 78 patients receiving axi-cel for large B cell lymphoma (LBCL) as of 12/31/2018. We evaluated all the patients who developed fever during lymphodepleting chemotherapy with fludarabine (Flu) and cyclophosphamide (Cy), after CAR T-cell infusion, and after administration of tocilizumab (toci); and analyzed the association of fever with toxicity rates (grade 3+ CRS and neurotoxicity) and efficacy [overall response rates (ORR) and complete response (CR) rate 6 months post CAR T-cell infusion]. Fever was defined per the Lee criteria [equal to or greater than 38 °C], CRS used the modified Lee criteria and neurotoxicity used the CARTOX grading system. Results: Fever occurred in 71/78 (91%) of patients. Rates of grade 3+ CRS and neurotoxicity were 9% (7/78) and 26% (20/78) respectively. The CR rate at 6 months was 41% (32/78). Toxicities and outcomes in patients with the described fever characteristics are shown in the Table. During lymphodepletion with Flu/Cy, fever was observed in 11% (9/78) of patients. Fever occurred within 24 hours of axi-cel infusion in 47% (37/78) and within 72 hours of axi-cel infusion in 71% (55/78) of the patients. In total, 41% (32/78) of patients were treated with anti-IL6R therapy (tocilizumab; toci) for CAR T toxicity. After the first dose of toci, fever recurred in 69% of patients (22/32), of which 34% (11/32) experienced fever recurrence within 24 hours of toci infusion. Conclusions: This is the first study to our knowledge that describes in detail the characteristics of fever after CAR T-cell therapy with axi-cel. Fever was common and occurred in 71% of the patients within 72 hours of axi-cel infusion. When toci was used, fever recurred in a majority of patients (69%) and in 1/3 of patients the fever recurred within 24 hours of toci infusion. These descriptive data may be used by clinicians to inform their expectations of fever occurring after treatment with axi-cel and/or toci. Table Disclosures Bachmeier: Kite/Gilead: Speakers Bureau. Chavez:Genentech: Speakers Bureau; Kite Pharmaceuticals, Inc.: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Janssen Pharmaceuticals, Inc.: Speakers Bureau. Shah:AstraZeneca: Honoraria; Novartis: Honoraria; Spectrum/Astrotech: Honoraria; Adaptive Biotechnologies: Honoraria; Pharmacyclics: Honoraria; Jazz Pharmaceuticals: Research Funding; Incyte: Research Funding; Kite/Gilead: Honoraria; Celgene/Juno: Honoraria. Pinilla Ibarz:Novartis: Consultancy; Bristol-Myers Squibb: Consultancy; Sanofi: Speakers Bureau; Takeda: Consultancy, Speakers Bureau; Bayer: Speakers Bureau; TG Therapeutics: Consultancy; Teva: Consultancy; Janssen: Consultancy, Speakers Bureau; Abbvie: Consultancy, Speakers Bureau. Nishihori:Novartis: Research Funding; Karyopharm: Research Funding. Lazaryan:Kadmon: Consultancy. Davila:Bellicum: Consultancy; Anixa: Consultancy; GlaxoSmithKline: Consultancy; Precision Biosciences: Consultancy; Novartis: Research Funding; Adaptive: Consultancy; Celgene: Research Funding; Atara: Research Funding. Locke:Cellular BioMedicine Group Inc.: Consultancy; Kite: Other: Scientific Advisor; Novartis: Other: Scientific Advisor. Jain:Kite/Gilead: Consultancy.

Description: Introduction: Of patients receiving CD19 CAR T cell therapy for large B cell lymphoma (LBCL), approximately 1 in 10 experience severe cytokine release syndrome (CRS) and 1 in 3 experience severe neurotoxicity. While CAR T cells trigger the onset of these toxicities, CRS and neurotoxicity are thought to occur as a consequence of activated myeloid cells amplifying cytokine and catecholamine release, thereby stimulating inflammation both systemically and at the blood-brain barrier. However, patient and tumor-related factors that account for differences in the amount of toxicity remain poorly understood. Methods: Serum cytokine levels were measured on an ELLA point of care device prior to lymphodepleting chemotherapy and throughout inpatient treatment with CD19 CAR T cell therapy (axicabtagene ciloleucel) for LBCL. Catecholamine levels were measured as we have previously reported. Tumor biopsies were taken within 1 month prior to infusion of CAR T cells. RNA expression was measured by RNAseq and/or a Nanostring IO360 panel consisting of 770 genes found in the tumor microenvironment (TME) in cancer. Analysis used nSolver to identify cell types, GSEA and differential gene expression between groups. Mouse CAR T cell studies utilized mouse CD19-targeted CAR T cells derived from C57BL/6 splenocytes and cultured in vitro with myeloid cells and target cells to evaluate cytotoxicity and/or cytokine secretion. Elicited mouse macrophages were collected from peritoneal fluid 4 days after IP injection of 3% Brewer's thioglycollate medium. In vivo studies with mouse CD19-targeted CAR T cells were performed in IL2Ra-/- mice given cyclophosphamide as a pre-conditioning chemotherapy followed by adoptive transfer and analyses for CAR T cell and B cell persistence, as well as cytokines. Results: Of 58 patients undergoing CD19 CAR T cell therapy for LBCL, 8 (14%) had severe (grade 3 or higher) CRS and 16 (28%) had severe (grade 3 or higher) neurotoxicity. At baseline, peripheral blood levels of IL-6, IFN-γ, IL-15 and ferritin were significantly higher in patients who would subsequently experience severe CRS and severe neurotoxicity. Confirming our recent animal model of CRS we determined that peak serum catecholamine levels were higher in patients experiencing severe CRS. To identify if myeloid cells potentiate cytokine release we co-cultured CAR T cells with CD19 target and macrophages obtained from elicited mouse peritoneum. When these macrophages were added, IL-6 release from CAR T cells significantly increased compared to when macrophages were absent. Next, we studied the baseline TME in LBCL CAR T patients. Of 36 patients, 10 (27%) experienced severe neurotoxicity following CAR T cell therapy. By cell type score, the severe neurotoxicity group had a lower expression of genes associated with T cells overall and specifically Tregs. Also significantly lower in the severe neurotoxicity group were T cell genes including multiple subunits of CD3, CD3ζ, FOXP3, ICOS, CD62L and others. Association of increased T cell infiltration in the TME with low neurotoxicity raised the possibility that suppressive T cell subsets play a role in limiting toxicity post-CAR T cell therapy. To test this hypothesis, we injected CD19-targeted CAR T cells into an immune competent mouse model of Treg depletion (IL2Ra-/-) with established CD19+ leukemia. Treg deficient mice experienced a massive cytokine release after CAR T infusion and died prematurely due to CAR T toxicity compared to control mice with Tregs intact. Conclusions: Our observations suggest that the incidence of severe toxicity following CD19 CAR T cell therapy is influenced by baseline characteristics that are present prior to the infusion of CAR T cells. These include systemic inflammation characterized by high cytokine levels and a TME notable for a lack of infiltrating T cells. We posit a model whereby inflammation primes myeloid cells that are further activated upon CAR T cell infusion to release toxic amounts of cytokines and catecholamines. T cell subsets in the TME may modulate CAR T cells at the site of antigen encounter and prevent excessive CAR T activation. Reducing systemic inflammation or encouraging T cell infiltration into tumor prior to CAR T infusion are potential strategies for lowering the toxicity associated with CAR T therapy. Disclosures Jain: Kite/Gilead: Consultancy. Chavez:Kite Pharmaceuticals, Inc.: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Genentech: Speakers Bureau; Janssen Pharmaceuticals, Inc.: Speakers Bureau. Shah:Novartis: Honoraria; Spectrum/Astrotech: Honoraria; Celgene/Juno: Honoraria; Kite/Gilead: Honoraria; Incyte: Research Funding; Jazz Pharmaceuticals: Research Funding; Pharmacyclics: Honoraria; Adaptive Biotechnologies: Honoraria; AstraZeneca: Honoraria. Bachmeier:Kite/Gilead: Speakers Bureau. Mullinax:Iovance: Research Funding. Locke:Novartis: Other: Scientific Advisor; Cellular BioMedicine Group Inc.: Consultancy; Kite: Other: Scientific Advisor. Davila:Anixa: Consultancy; Precision Biosciences: Consultancy; Novartis: Research Funding; GlaxoSmithKline: Consultancy; Adaptive: Consultancy; Celgene: Research Funding; Atara: Research Funding; Bellicum: Consultancy.