Product Attributes of CAR T-cell Therapy Differentially Associate with Efficacy and Toxicity in Second-line Large B-cell Lymphoma (ZUMA-7)

Treatment resistance and toxicities remain a risk following chimeric antigen receptor (CAR) T-cell therapy. Herein, we report pharmacokinetics, pharmacodynamics, and product and apheresis attributes associated with outcomes among patients with relapsed/refractory large B-cell lymphoma (LBCL) treated with axicabtagene ciloleucel (axi-cel) in ZUMA-7. Axi-cel peak expansion associated with clinical response and toxicity, but not response durability. In apheresis material and final product, a naive T-cell phenotype (CCR7+CD45RA+) expressing CD27 and CD28 associated with improved response durability, event-free survival, progression-free survival, and a lower number of prior therapies. This phenotype was not associated with high-grade cytokine release syndrome (CRS) or neurologic events. Higher baseline and postinfusion levels of serum inflammatory markers associated with differentiated/effector products, reduced efficacy, and increased CRS and neurologic events, thus suggesting targets for intervention. These data support better outcomes with earlier CAR T-cell intervention and may improve patient care by informing on predictive biomarkers and development of next-generation products.

SIGNIFICANCE

In ZUMA-7, the largest randomized CAR T-cell trial in LBCL, a naive T-cell product phenotype (CCR7+CD45RA+) expressing CD27 and CD28 associated with improved efficacy, decreased toxicity, and a lower number of prior therapies, supporting earlier intervention with CAR T-cell therapy. In addition, targets for improvement of therapeutic index are proposed. This article is featured in Selected Articles from This Issue, p. 4.

Severity of Chronic Graft-versus-Host Disease and Late Effects Following Allogeneic Hematopoietic Cell Transplantation for Adults with Hematologic Malignancy

The study aimed to determine the association of chronic graft-versus-host disease (cGVHD) diagnosis and severity with the development of subsequent neoplasms (SN) and nonmalignant late effects (NM-LE) in 2-year disease-free adult survivors following hematopoietic cell transplantation (HCT) for a hematologic malignancy. To do so, we conducted a retrospective analysis of 3884 survivors of HCT for hematologic malignancy in the Center of International Blood and Marrow Transplant Research database. We conducted a landmark analysis at the 2-year post-transplantation date, comparing first SN and NM-LE in survivors with and without cGVHD. The cumulative incidence (CuI) of SN and NM-LE were estimated through 10 years post-HCT in both groups, with death or disease relapse as a competing risk. Cox proportional hazards models were used to evaluate the associations of cGVHD and its related characteristics with the development of SN and NM-LE. The estimated 10-year CuI of SN in patients with GVHD (n = 2669) and patients without cGVHD (n = 1215) was 15% (95% confidence interval [CI], 14% to 17%) versus 9% (7.2% to 11%) (P < .001). cGVHD by 2 years post-HCT was independently associated with SN (hazard ratio [HR], 1.94; 95% CI, 1.53 to 2.46; P < .0001) with a standardized incidence ratio of 3.2 (95% CI, 2.9 to 3.5; P < .0001). Increasing severity of cGVHD was associated with an increased risk of SN. The estimated 10-year CuI of first NM-LE in patients with and without cGVHD was 28 (95% CI, 26% to 30%) versus 13% (95% CI, 11% to 15%) (P < .001). cGVHD by 2 years post-HCT was independently associated with NM-LE (HR, 2.23; 95% CI, 1.81 to 2.76; P < .0001). Multivariate analysis of cGVHD-related factors showed that increasing severity of cGVHD, extensive grade, having both mucocutaneous and visceral involvement, and receiving cGVHD treatment for >12 months were associated with the greatest magnitude of risk for NM-LE. cGVHD was closely associated with both SN and NM-LE in adult survivors of HCT for hematologic malignancy. Patients identified as having more severe involvement and both mucocutaneous and visceral organ involvement may warrant enhanced monitoring and screening for SNs and NM-LEs. However, caution is warranted when interpreting these results, as patients with cGVHD may have more vigilant post-transplantation health care and surveillance for late effects.

Allogeneic hematopoietic cell transplantation for blastic plasmacytoid dendritic cell neoplasm: a CIBMTR analysis

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare hematological malignancy with a poor prognosis and considered incurable with conventional chemotherapy. Small observational studies reported allogeneic hematopoietic cell transplantation (allo-HCT) offers durable remissions in patients with BPDCN. We report an analysis of patients with BPDCN who received an allo-HCT, using data reported to the Center for International Blood and Marrow Transplant Research (CIBMTR). We identified 164 patients with BPDCN from 78 centers who underwent allo-HCT between 2007 and 2018. The 5-year overall survival (OS), disease-free survival (DFS), relapse, and nonrelapse mortality (NRM) rates were 51.2% (95% confidence interval [CI], 42.5-59.8), 44.4% (95% CI, 36.2-52.8), 32.2% (95% CI, 24.7-40.3), and 23.3% (95% CI, 16.9-30.4), respectively. Disease relapse was the most common cause of death. On multivariate analyses, age of ≥60 years was predictive for inferior OS (hazard ratio [HR], 2.16; 95% CI, 1.35-3.46; P = .001), and higher NRM (HR, 2.19; 95% CI, 1.13-4.22; P = .02). Remission status at time of allo-HCT (CR2/primary induction failure/relapse vs CR1) was predictive of inferior OS (HR, 1.87; 95% CI, 1.14-3.06; P = .01) and DFS (HR, 1.75; 95% CI, 1.11-2.76; P = .02). Use of myeloablative conditioning with total body irradiation (MAC-TBI) was predictive of improved DFS and reduced relapse risk. Allo-HCT is effective in providing durable remissions and long-term survival in BPDCN. Younger age and allo-HCT in CR1 predicted for improved survival, whereas MAC-TBI predicted for less relapse and improved DFS. Novel strategies incorporating allo-HCT are needed to further improve outcomes.

Impact of second primary malignancy post-autologous transplantation on outcomes of multiple myeloma: a CIBMTR analysis

The overall survival (OS) has improved significantly in multiple myeloma (MM) over the last decade with the use of proteasome inhibitor and immunomodulatory drug-based combinations, followed by high-dose melphalan and autologous hematopoietic stem cell transplantation (auto-HSCT) and subsequent maintenance therapies in eligible newly diagnosed patients. However, clinical trials using auto-HSCT followed by lenalidomide maintenance have shown an increased risk of second primary malignancies (SPM), including second hematological malignancies (SHM). We evaluated the impact of SPM and SHM on progression-free survival (PFS) and OS in patients with MM after auto-HSCT using CIBMTR registry data. Adult patients with MM who underwent first auto-HSCT in the United States with melphalan conditioning regimen from 2011 to 2018 and received maintenance therapy were included (n = 3948). At a median follow-up of 37 months, 175 (4%) patients developed SPM, including 112 (64%) solid, 36 (20%) myeloid, 24 (14%) SHM, not otherwise specified, and 3 (2%) lymphoid malignancies. Multivariate analysis demonstrated that SPM and SHM were associated with an inferior PFS (hazard ratio [HR] 2.62, P < .001 and HR 5.01, P < .001, respectively) and OS (HR 3.85, P < .001 and HR 8.13, P < .001, respectively). In patients who developed SPM and SHM, MM remained the most frequent primary cause of death (42% vs 30% and 53% vs 18%, respectively). We conclude the development of SPM and SHM leads to a poor survival in patients with MM and is an important survivorship challenge. Given the median survival for MM continues to improve, continued vigilance is needed to assess the risks of SPM and SHM with maintenance therapy post-auto-HSCT.

Dual targeting of CD19 and CD22 with bicistronic CAR-T cells in patients with relapsed/refractory large B-cell lymphoma

Relapse after CD19-directed chimeric antigen receptor T-cell (CAR-T) therapy for large B-cell lymphoma (LBCL) is commonly ascribed to antigen loss or CAR-T exhaustion. Multiantigen targeting and programmed cell death protein-1 blockade are rational approaches to prevent relapse. Here, we test CD19/22 dual-targeting CAR-T (AUTO3) plus pembrolizumab in relapsed/refractory LBCL (NCT03289455). End points include toxicity (primary) and response rates (secondary). Fifty-two patients received AUTO3 and 48/52 received pembrolizumab. Median age was 59 years (range, 27-83), 46/52 had stage III/ IV disease and median follow-up was 21.6 months. AUTO3 was safe; grade 1-2 and grade 3 cytokine release syndrome affected 18/52 (34.6%) and 1/52 (1.9%) patients, neurotoxicity arose in 4 patients (2/4, grade 3-4), and hemophagocytic lymphohistiocytosis affected 2 patients. Outpatient administration was tested in 20 patients, saving a median of 14 hospital days per patient. Overall response rates were 66% (48.9%, complete response [CR]; 17%, partial response). Median duration of remission (DOR) for CR patients was not reached and for all responding patients was 8.3 months (95% confidence interval [CI]: 3.0-not evaluable). 54.4% (CI: 32.8-71.7) of CR patients and 42.6% of all responding patients were projected to remain progression-free at ≥12 months. AUTO3 ± pembrolizumab for relapsed/refractory LBCL was safe and delivered durable remissions in 54.4% of complete responders, associated with robust CAR-T expansion. Neither dual-targeting CAR-T nor pembrolizumab prevented relapse in a significant proportion of patients, and future developments include next-generation-AUTO3, engineered for superior expansion in vivo, and selection of CAR binders active at low antigen densities.

Five-year follow-up of ZUMA-1 supports the curative potential of axicabtagene ciloleucel in refractory large B-cell lymphoma

In phase 2 of ZUMA-1, a single-arm, multicenter, registrational trial, axicabtagene ciloleucel (axi-cel) autologous anti-CD19 chimeric antigen receptor (CAR) T-cell therapy demonstrated durable responses at 2 years in patients with refractory large B-cell lymphoma (LBCL). Here, we assessed outcomes in ZUMA-1 after 5 years of follow-up. Eligible adults received lymphodepleting chemotherapy followed by axi-cel (2 × 106 cells per kg). Investigator-assessed response, survival, safety, and pharmacokinetics were assessed in patients who had received treatment. The objective response rate in these 101 patients was 83% (58% complete response rate); with a median follow-up of 63.1 months, responses were ongoing in 31% of patients at data cutoff. Median overall survival (OS) was 25.8 months, and the estimated 5-year OS rate was 42.6%. Disease-specific survival (excluding deaths unrelated to disease progression) estimated at 5 years was 51.0%. No new serious adverse events or deaths related to axi-cel were observed after additional follow-up. Peripheral blood B cells were detectable in all evaluable patients at 3 years with polyclonal B-cell recovery in 91% of patients. Ongoing responses at 60 months were associated with early CAR T-cell expansion. In conclusion, this 5-year follow-up analysis of ZUMA-1 demonstrates sustained overall and disease-specific survival, with no new safety signals in patients with refractory LBCL. Protracted B-cell aplasia was not required for durable responses. These findings support the curative potential of axi-cel in a subset of patients with aggressive B-cell lymphomas. This trial was registered at ClinicalTrials.gov, as #NCT02348216.

Abstract 5879: Defining the cancer Immunogram using multimodal analysis to guide immunotherapy in diffuse large B cell lymphoma

(a) Expansion of therapeutic strategies against diffuse large B-cell lymphoma (DLBCL) offers new opportunities to fight aggressive non-Hodgkin's lymphoma. Therapy approaches, such as R-CHOP and stem cell transplant, and CAR-T cell therapies are now available for the treatment of DLBCL. While the role of the tumor microenvironment (TME) during the therapeutic response is now recognized, the spatial organization and the communication between the diverse factors that compose the TME remains to be fully understood. In this study, we describe a new immunogram tool to help clinical researchers measure the tumor microenvironment contribution to drug efficacy or toxicity in DLBCL context.

(b) In a previous work, using a high-quality testing and innovative multimodal and integrative approach, we constructed the first Veracyte Biopharma Atlas for DLBCL lesions. Based on this knowledge and the understanding of the immune contexture of tumors, we constructed an immunogram using the scoring of clinically relevant biomarkers. Our immunogram scoring approach is composed of key features driving computational derivation of DLBCL Atlas clusters, which include immune gene signatures, immune cell phenotyping combined with spatial information, and genomic and clinical parameters.

(c) Patterns that strongly associated with CAR-T treatment response were determined. In addition, promising results have been obtained in the prediction to CAR-T toxicity related to T-regulatory cells or R-CHOP response with transcriptomic signature.

(d) Retrospective analysis of CAR-T clinical trial data and tumor biopsies highlighted the Veracyte Immunogram as a powerful tool to score the patient probability of response to CAR-T. This work provides the framework for identification of predictors of response to therapy, potential targets of interest or biomarkers that could be applied in future clinical trials.

Citation Format: Michael D. Mattie, Regis Perbost, Sarah Turcan, Corinne Danan, Frederick L. Locke, Sattva S. Neelapu, David B. Miklos, Caron A. Jacobson, Lazaros J. Lekakis, Yi Lin, Armin Ghobadi, Jenny J. Kim, Zixing Wang, Allen Xue, Simone Filosto, Nathalie Scholler, Jerome Galon. Defining the cancer Immunogram using multimodal analysis to guide immunotherapy in diffuse large B cell lymphoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5879.

Association of Chronic Graft-versus-Host Disease with Late Effects following Allogeneic Hematopoietic Cell Transplantation for Children with Hematologic Malignancy

Chronic graft-versus-host disease (cGVHD) occurs in up to 25% of children following allogeneic hematopoietic cell transplantation (HCT) and continues to be a major cause of late morbidity and poor quality of life among long-term survivors of pediatric HCT. Late effects (LEs) of HCT are well documented in this population, and cGVHD has been identified as a risk factor for subsequent neoplasms (SNs) and several nonmalignant LEs (NM-LEs); however, the reported correlation between cGVHD and LEs varies among studies. We compared LEs occurring ≥2 years following childhood HCT for a hematologic malignancy in 2-year disease-free survivors with and without cGVHD and further evaluated the association of cGVHD features on the development of LEs. This systematic retrospective analysis used data from the Center of International Blood and Marrow Transplant Research (CIBMTR) on a large, representative cohort of 1260 survivors of pediatric HCT for hematologic malignancy to compare first malignant LEs and NM-LEs in those with a diagnosis of cGVHD and those who never developed cGVHD. The cumulative incidences of any first LE, SN, and NM-LE were estimated at 10 years after HCT, with death as a competing risk for patients with cGVHD versus no cGVHD. Cox proportional hazards models were used to evaluate the impact of cGVHD and its related characteristics on the development of first LEs. The estimated 10-year cumulative incidence of any LE in patients with and without cGVHD was 43% (95% CI, 38% to 48.2%) versus 32% (95% confidence interval [CI], 28.5% to 36.3%) (P < .001), respectively. The development of cGVHD by 2 years post-HCT was independently associated with any LE (hazard ratio [HR], 1.38; 95% CI, 1.13 to 1.68; P = .001) and NM-LE (HR, 1.37; 95% CI, 1.10 to 1.70; P = .006), but not SN (HR, 1.30; 95% CI, .73 to 2.31; P = .38). cGVHD-related factors linked with the development of an NM-LE included having extensive grade cGVHD (HR, 1.60; 95% CI, 1.23 to 2.08; P = .0005), severe cGVHD (HR, 2.25; 95% CI, 1.60 to 3.17; P < .0001), interrupted onset type (HR, 1.57; 95% CI, 1.21 to 2.05; P = .0008), and both mucocutaneous and visceral organ involvement (HR, 1.59; 95% CI, 1.24 to 2.03; P = .0002). No significant association between cGVHD-specific variables and SN was identified. Finally, the duration of cGVHD treatment of cGVHD with systemic immunosuppression was not significantly associated with SNs or NM-LEs. cGVHD was more closely associated with NM-LEs than with SNs among survivors of pediatric HCT for hematologic malignancy. In this analysis, the development of SNs was strongly associated with the use of myeloablative total body irradiation. cGVHD-related characteristics consistent with a state of greater immune dysregulation were more closely linked to NM-LEs.

Abstract CT004: Product attributes of axicabtagene ciloleucel (axi-cel) that associate differentially with efficacy and toxicity in second-line large B-cell lymphoma

Background: Axi-cel is an autologous anti-CD19 chimeric antigen receptor (CAR) T-cell therapy approved for the treatment of relapsed or refractory large B-cell lymphoma after ≥2 lines of systemic therapy. ZUMA-7, a global Phase 3 randomized study, showed superiority of axi-cel over standard second-line therapy (N=359; event-free survival [EFS] HR 0.398, P&lt;.0001; median EFS 8.3 vs 2 months; estimated 2-year EFS 41% vs 16%; objective response rate [ORR] 83% vs 50%, Locke et al. N Engl J Med. 2021). Here we report axi-cel pharmacokinetics (PK), pharmacodynamics (PD), and product attributes associated with ZUMA-7 clinical outcomes.

Methods: Samples from patients who received axi-cel (n=170) were analyzed. PK, PD, and axi-cel T-cell composition (naive, CCR7+CD45RA+; differentiated, CCR7-) were assessed for associations with safety and efficacy using previously described methodologies (Neelapu et al. NEJM. 2017; Locke et al. Blood Adv. 2020).

Results: The median (Q1, Q3; n=162) peak CAR T-cell level, time to peak, and area under the curve within the first 28 days of treatment (AUC0-28) were 25.8 cells/μL (8.2, 57.9), 8 days (8, 9), and 236.2 cells/μL*days (76.4, 758.0), respectively. CAR T-cell peak and AUC0-28 correlated with higher ORR (P=.0224 and .0054, respectively) and increased Grade (Gr) ≥3 neurologic events (NEs; P=.0006) but not with durability of response (P=.4894). Rapid transient increases in serum analytes, including granzyme B, ferritin, IL-6, IL-10, CXCL-10, IL-15, ICAM-1, and GM-CSF, occurred early (median peak ≤7 days) and were associated with increased Gr ≥3 NEs and Gr ≥3 cytokine release syndrome (CRS; P&lt;.05). Infusion products richer in naive-like T cells expressing CD27 and CD28 associated with increased EFS, ORR, and complete response (P&lt;.05). In contrast, infusion products richer in differentiated T cells (CCR7-) and with lower % of CCR7+CD45RA+ T cells associated with higher postinfusion peak levels and AUC0-28 of several proinflammatory and immunomodulatory serum analytes (eg, IL-15, ferritin, IFN-γ). Increased rates of Gr ≥3 NEs were found in patients who received axi-cel richer in CCR7- T cells (above median: 30% vs below median: 10%). Similarly, a trend of higher rates of Gr ≥3 NEs and CRS were observed in patients who received axi-cel that secreted higher levels of IFN-γ in co-culture with CD19-expressing targets.

Conclusions: Preinfusion axi-cel features and postinfusion PK/PD profiles in the randomized phase 3 ZUMA-7 trial were associated with safety and efficacy outcomes and supported that optimizing product composition towards a juvenile T-cell phenotype (CCR7+CD45RA+) may improve axi-cel therapeutic index. These findings could result in future trials to evaluate if preemptive interventions, including enrichment of naive T cells in the product, could improve outcomes. [SF and SV contributed equally]

Citation Format: Simone Filosto, Saran Vardhanabhuti, Miguel Canales, Xavier Poiré, Lazaros J. Lekakis, Sven de Vos, Craig A. Portell, Zixing Wang, Christina To, Paul Cheng, Justin Chou, Adrian Bot, Rhine Shen, Jason R. Westin. Product attributes of axicabtagene ciloleucel (axi-cel) that associate differentially with efficacy and toxicity in second-line large B-cell lymphoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr CT004.

Brexucabtagene autoleucel for relapsed/refractory mantle cell lymphoma: Real-world experience from the United States lymphoma CAR T consortium

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Background: Brexucabtagene autoleucel (BA) is an FDA approved therapy for relapsed/refractory (R/R) mantle cell lymphoma (MCL), based on results from ZUMA-2 study. We report the safety and efficacy of BA in standard of care practice among centers in the US Lymphoma CAR-T Consortium. Methods: 16 centers participated in this retrospective study. Patients (pts) who underwent leukapheresis by 12/31/2021 with an intent to manufacture BA were included. Baseline clinical characteristics, bridging therapy, adverse events after BA infusion, and post-infusion outcome data were collected. Eligibility for ZUMA-2 was retrospectively determined. Survival outcomes were analyzed using the Kaplan-Meier method. Results: At the data cut-off date, 189 pts underwent leukapheresis, among whom 167 (88%) completed BA infusion, 22 (12%) did not receive infusion. The median age was 67 years. 16% had high risk simplified MIPI, 57% had Ki-67≥50%, 41% had aggressive histology, 49% had TP53 alteration, 51% with POD24 and 10% had CNS involvement. The median number of prior lines of therapy was 3 (range 1-10). 86% had prior BTKi treatment (89% refractory). 130 (78%) pts would not have met ZUMA-2 eligibility criteria. 113 (68%) pts received bridging therapy, which included BTKi, venetoclax, chemotherapy. Median time from leukapheresis to lymphodepletion chemotherapy: 28 days (range 17-140). Cytokine release syndrome (CRS) rate was 90% (8% grade ≥3; 1 grade 5), and immune effector cell-associated neurotoxicity syndrome (ICANS) rate was 61% (32% grade ≥3). Grade 5 ICANS (n = 0). Medications used to manage CRS and ICANS were 125 (76%) for tocilizumab, 112 (68%) for corticosteroid, and 27 (16%) for anakinra. 32 (20%) pts required ICU admission, 18 pts required vasopressors, and 5 pts required mechanical ventilation. Day 30 response was evaluable in 155 pts (89% ORR, 70% CR). The best ORR was 89%, with 80% CR, 9% PR. The ORR/CR rates were 88%/79% for aggressive histology, 89%/77% for high Ki-67% (> 50%), 90%/72% for TP53 altered, 81%/75% for CNS involved, 89%/79% for BTKi-exposed, 91%/83% for BTKi-naïve, and 89%/78% for those not meeting ZUMA-2 eligibility criteria. The median duration of response was not reached and at 6-month was 67% (95% CI 57-75). With a median follow-up of 5.6 months (range 0.2-15.3), median PFS was not reached, the 6-month PFS rate was 63% (95% CI 54-71), and median OS was 15.3 months and the 6-month OS rate was 85% (95% CI 77-90). Conclusions: This multicenter retrospective study demonstrated encouraging safety and efficacy data of BA in R/R MCL in the real-world practice. Despite 78% of the pts being ineligible for ZUMA-2, the responses, CRS, ICANS and outcomes were comparable to ZUMA-2 data. Long term safety and efficacy will be reported.

Chronic Graft-versus-Host Disease, Nonrelapse Mortality, and Disease Relapse in Older versus Younger Adults Undergoing Matched Allogeneic Peripheral Blood Hematopoietic Cell Transplantation: A Center for International Blood and Marrow Transplant Research Analysis

The effect of chronic graft-versus-host disease (cGVHD) on the risk of nonrelapse mortality (NRM) and relapse has not been specifically studied in older adults, who are increasingly undergoing allogeneic hematopoietic cell transplantation (alloHCT) and surviving long-term to develop cGVHD. In this Center for International Blood and Marrow Transplant Research (CIBMTR) analysis, we tested our hypothesis that the risk of NRM was higher with the development of cGVHD, particularly among older adults (age ≥60 years). We included 4429 adults age ≥40 years who underwent a first HLA-matched peripheral blood stem cell alloHCT for acute myelogenous leukemia or myelodysplastic syndrome between 2008 and 2017. We compared outcomes of 4 groups-older adults (≥60 years) and younger adults (40 to 59 years) with cGVHD and older and younger adults without cGVHD-to determine the effect of older age and cGVHD on various outcomes. We used Cox proportional hazard models to determine the risk of NRM, relapse, and overall survival (OS). We treated cGVHD as a time-dependent covariate. The severity of cGVHD was based on the CIBMTR clinical definitions. cGVHD was significantly associated with a higher risk of NRM and lower risk of relapse regardless of age. The risk of NRM was higher for older adults versus younger adults. Adults who developed cGVHD as a group had longer OS compared with age-matched cohorts without cGVHD. Older adults had worse OS regardless of cGVHD. Among adults with cGVHD, clinically moderate or severe cGVHD was associated with a significantly higher risk of NRM and lower risk of relapse; severe cGVHD was associated with shorter OS, whereas mild to moderate cGVHD was associated with longer OS. Among both younger and older adults, the development of cGVHD was associated with a higher risk of NRM, lower risk of relapse, and longer OS. Older adults had a higher risk of NRM, but the increased risk of NRM associated with cGVHD did not differ based on age. The development of mild to moderate cGVHD offered the most favorable balance between minimizing NRM and decreasing the risk of relapse. The relapse risk was lowest for adults with severe cGVHD, but high NRM resulted in shorter OS. Developing strategies to avoid clinically severe cGVHD is critically important. © 2021 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc.

Abstract CT166: Pretreatment (PreTx) immune cell phenotypes in peripheral blood associated with the tumor immune contexture, product attributes, and durable clinical efficacy in patients with large B-cell lymphoma (LBCL) treated with axicabtagene ciloleucel (axi-cel)

Background: Conventional prognostic factors for LBCL were not associated with outcomes in the pivotal ZUMA-1 study of axi-cel in relapsed LBCL (Neelapu et al. NEJM. 2017); however, other attributes like chimeric antigen receptor (CAR) T-cell fitness and composition (CCR7+CD45RA+ T cells), reduced preTx tumor burden, and immune tumor microenvironment (TME) with presence of activated CD8+PD-1+LAG-3+/-TIM-3- T cells were associated with efficacy (Locke et al. Blood Adv. 2020; Galon et al. ASCO 2020. #3022). Here, we evaluated preTx immune cell phenotypes in premanufacturing apheresis (premfg aph) material, comprising peripheral blood mononuclear cells, to determine associations with product attributes, immune TME features, and clinical efficacy in ZUMA-1. Methods: Evaluable samples from patients (pts) in Phase (Ph) 1 and Ph2 Cohorts (C) 1-3 were analyzed (NCT02348216; Ph1 and Ph2 C1+2, ≥2-y follow-up; C3, ≥6-mo follow-up). Memory T, myeloid, NK, NKT, and B cells in premfg aph material (n=101, excluding C3) were characterized by flow cytometry (FC). PreTx immune TME was analyzed by multiplex IHC (n=18) and gene expression analysis (n=30) as previously described (Rossi et al. AACR 2018. #LB-016; Galon et al. ASCO 2020. #3022). CAR T-cell fitness was analyzed by doubling time, viability during manufacturing, and product T-cell phenotypes by FC (n=145). Associations between these covariates, and with routine hematology tests, were performed by Spearman rank correlation or Wilcoxon tests. Effects on survival were assessed by Kaplan-Meier with optimized cutpoint selection. Results: The percentage (%) of naive (CCR7+CD45RA+) T helper (Th; CD4+CD127+CD25low) cells coexpressing CD27 and CD28 (median, 1%; range, 0.01%-15.8%; IQR, 0.3%-3.8%) in aph associated positively with axi-cel efficacy. The % of intermediate monocytes (IMs; CD14+CD16+; median, 1.8%; range, 0.003%-16.7%; IQR, 1%-3%) in aph associated negatively with efficacy. The % of circulating CD27+CD28+ naive Th cells associated positively with an enriched preTx immune TME T-cell signature, % CCR7+CD45RA+ product T cells, objective response rate, PFS, and OS. An increased % of IMs associated directly with negative predictive markers (preTx serum levels of LDH, IL-6, and CRP) and inversely with TME T-cell signature, PFS, and OS. The premfg ratio of CD27+CD28+ naive Th cells/IMs associated directly with CAR T-cell expansion and efficacy. Conclusions: This work points to a link between the pre-existing state of the immune system, reflected in premfg aph, and immune TME, as well as product attributes influencing axi-cel efficacy in LBCL. These data bear practical implications towards the development of predictive biomarkers for axi-cel efficacy. [JB and JC contributed equally.]

Citation Format: Justin Budka, Justin Chou, Vicki Plaks, Francesca Milletti, Zixing Wang, Frederick L. Locke, Sattva S. Neelapu, David B. Miklos, Caron A. Jacobson, Lazaros J. Lekakis, Yi Lin, Armin Ghobadi, Zahid Bashir, Nathalie Scholler, Jérôme Galon, John M. Rossi, Adrian Bot. Pretreatment (PreTx) immune cell phenotypes in peripheral blood associated with the tumor immune contexture, product attributes, and durable clinical efficacy in patients with large B-cell lymphoma (LBCL) treated with axicabtagene ciloleucel (axi-cel) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr CT166.

First-in-human data of ALLO-501A, an allogeneic chimeric antigen receptor (CAR) T-cell therapy and ALLO-647 in relapsed/refractory large B-cell lymphoma (R/R LBCL): ALPHA2 study

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Background: Allogeneic CAR T cell therapy addresses logistical/manufacturing challenges inherent in autologous (auto) CAR T therapy. ALLO-501A, which uses Cellectis technologies, is an allogeneic anti-CD19 CAR T cell product whose a) disrupted TCRα gene may reduce GvHD risk, and b) edited CD52 gene may permit use of ALLO-647 (a humanized anti-CD52 mAb) to selectively deplete host T cells. Methods: The ongoing ALPHA2 study is a single-arm, open-label, 2 phase study of ALLO-501A in non-HLA matched patients (pts) with R/R LBCL and ≥2 prior lines of therapy. Prior auto CD19 CAR T therapy is allowed if tumors remain CD19+. Following lymphodepletion (LD) with ALLO-647 (60 mg or 90 mg), fludarabine 30 mg/m2/d x 3d (Flu), and cyclophosphamide 300 mg/m2/d x 3d (Cy), escalating doses of ALLO-501A (40 [DL1] or 120 [DL2] x 106 viable CAR T cells) were administered. Retreatment was allowed for PD or SD with suboptimal CAR T expansion. Pts who had ≥SD at D28 could receive a second dose in a consolidation cohort. Phase 1 assessed safety/tolerability and cell kinetics of escalating doses of ALLO-501A following LD. Results: By 1/15/21, 11/11 enrolled pts received ALLO-647 (60 mg: n=6; 90 mg: n=5). Mean duration from enrollment to start of therapy was 6 days. After LD, 1 and 9 pt(s) were treated with ALLO-501A at DL1 and DL2, respectively; 1 pt developed CNS lymphoma and was not treated. Of 10 pts treated, 1 pt received retreatment and 4 pts were enrolled in the consolidation cohort. Pts had a median age of 60 years; 8 were ≥ stage III at diagnosis, 5 had IPI scores ≥3, and 3 had baseline LDH > 2x ULN. Median number of prior therapies was 3 (range 2 – 7); 3 pts had received auto CD19 CAR T cell therapy. 4/8 evaluable pts had rapidly PD at study entry. Median FU was 1.7 months. No dose modifications were required and no pt experienced DLTs. The most common AEs were anemia, leukopenia, neutropenia and thrombocytopenia (73%); and lymphopenia (64%). No GvHD or ICANS were reported. CRS was seen in 2 (18%) pts, both Grade < 3. Infusion-related reactions, all grade <3, were observed in 4 (36%) pts. D28 response data are available for 8 pts: 1 died of PD before D28; 4 additional pts had PD, including 2 who progressed 2 and 3 mos. after auto CAR T; 1 had SD; and 2 (both DL2) had CR. Of those in CR, 1 had peak ALLO-501A expansion at D14, persistence until D42, and ongoing CR at 4 mo; 1, with a 4-mo response to prior auto CAR T, had peak expansion at D28 and remains in ongoing CR at D56 after ALLO-501A with pending persistence. Conclusions: This dose escalation cohort contained heavily pretreated, actively progressing pts, some of whom had failed auto CAR T. Preliminary data suggest an acceptable safety profile following ALLO-501A and ALLO-647 and early signs of efficacy in LBCL. Enrollment into the consolidation cohort is ongoing; updated clinical/biomarker data of resistance and clinical activity will be presented. Clinical trial information: NCT04416984.

Aseptic Meningitis after Recovery from SARS-CoV-2 in an Allogeneic Stem Cell Transplant Recipient

SARS-CoV-2 emerged as a worldwide pandemic in late 2019 and initially was described as a primary respiratory illness. The clinical manifestations of COVID-19 are now known to encompass nearly all organ systems, including the central nervous system. We present a case of an allogeneic hematopoietic stem cell transplant recipient who recovered from documented SARS-CoV-2 infection and later presented with symptoms of meningitis. While cerebrospinal fluid analysis did not reveal any bacterial or viral etiologies, evidence of an inflammatory state, including ophthalmologic findings of episcleritis, indicate what is likely the first reported case of aseptic meningitis associated with SARS-CoV-2 infection after initial clinical recovery.

Tumor microenvironment associated with increased pretreatment density of activated PD-1+ LAG-3+/− TIM-3− CD8+ T cells facilitates clinical response to axicabtagene ciloleucel (axi-cel) in patients (pts) with large B-cell lymphoma

3022

Background: Axi-cel is a US and EU-approved autologous anti-CD19 chimeric antigen receptor (CAR) T cell therapy for pts with relapsed/refractory large B cell lymphoma after ≥ 2 prior therapies. In ZUMA-1 (NCT02348216), the objective response rate was 83% (58% complete response rate; Locke et al. Lancet Oncol. 2019). T cell-related biology (Immunosign 21; Immunoscore) measured pretreatment in the tumor microenvironment (TME) was associated with response to axi-cel (Rossi et al. AACR 2018. #LB-016; Rossi et al. AACR 2019. #CT153). This expanded analysis characterized the pretreatment TME immune contexture and examined associations between immune cell subsets and response. Methods: In ZUMA-1, pts received axi-cel at a target dose of 2.0 × 106 CAR T cells/kg. Archival pretreatment tumor biopsy samples were analyzed by multiplex immunohistochemistry (Brightplex). Two panels were developed and applied to assess T cell (CD3, CD8, FoxP3, PD-1, LAG-3, TIM-3) and myeloid cell (CD11b, CD14, CD15, LOX1, S100A9, CD68) subsets (n = 14 total). The association between T cell and myeloid cell subset density, prespecified immune scores (Immunosign 21; Immunoscore), and objective response was evaluated. T test values were based on Brightplex analysis. Results: Pretreatment tumor biopsy samples from 18 pts were analyzed (14 objective responders and 4 nonresponders). The pretreatment TME comprised all major myeloid and T cell subsets, with diverse distribution across samples analyzed. The median TME density of monocytes (CD11b+ CD15− CD14+; 1215 cells/mm2) and macrophages (CD68+; 530 cells/mm2) was greater than that of the total CD8+ T cell subset (312 cells/mm2). The pretreatment Immunosign 21 and Immunoscore scores associated positively with the density of all major T cell subsets and some myeloid subsets. The density of activated CD8+ T cells (PD-1+ LAG-3+/− TIM-3−) was most significantly associated with clinical response versus other T cell subsets. The density of nonactivated CD8+ T cells (PD-1− LAG-3− TIM-3−) and exhausted CD8+ T cells (PD-1+ LAG-3+ TIM-3+) were not significantly associated with response. Additional characterization of the immune contexture and correlative analysis of cell subsets will be presented. Conclusions: These results suggest that a TME associated with increased density of activated PD-1+ LAG-3+/− TIM-3− CD8+ T cells, measurable pretreatment, facilitates clinical response in pts post–axi-cel.

Adult lymphoma-associated hemophagocytic lymphohistiocytosis: A clinical case series in a predominantly Hispanic cohort from the University of Miami/Jackson Memorial Hospital

e20060

Background: Hemophagocytic Lymphohistiocytosis (HLH) is a systemic inflammation disorder secondary to immune dysregulation. Patients may present with fevers, splenomegaly, bone marrow failure, and hemophagocytosis, among other clinical and laboratory findings. Lymphoma Associated HLH (LA-HLH) is a puzzling diagnosis given both conditions overlapping presentation. There are currently no established treatment guidelines for LA-HLH. Methods: We conducted a retrospective search of the tumor registry and pathology database at the University of Miami/Jackson Memorial Hospital to identify adult patients with the combined diagnosis of Lymphoma and HLH between January 2008 and July 2018. Results: Data from nine LA-HLH patients were identified and reviewed. Median age was 53 years (range 19-73), with 78% of cases of Hispanic origin. Lymphoma subtypes consisted of six T-cell/NK-cell neoplasms - 2 Peripheral T-cell Lymphomas (PTCL), NOS; 2 EBV+ Extranodal NK/T-Cell Lymphomas; 1 EBV+, CD8+, PTCL, NOS; 1 EBV+, Post-Transplant Lymphoproliferative Disorder-Anaplastic Large Cell Lymphoma, ALK negative (PTLD ALCL ALK-); and three B-cell neoplasms - 1 EBV+ DLBCL; 2 DLBCL, NOS. HLH and Lymphoma were diagnosed simultaneously in 6/9 cases. Hemophagocytosis phenomena was demonstrated in 7/9 cases. Treatment consisted of combined HLH and Lymphoma therapies in 4 cases, while Lymphoma directed therapy was applied to four patients; another case was treated with a modified version of the HLH-1994 protocol. Overall, a total of five cases were exposed to HLH-directed regimens (HLH-1994/2004). Three patients had refractory LA-HLH and entered hospice care, whereas another 3 cases succumbed to treatment-related complications. Of the seven cases that were evaluable for Lymphoma response, four cases (57%) achieved CR, and three of them (43%) were alive with no evidence of recurrence at 10, 16, and 52 months as of last contact. Conclusions: Herein, we describe our unique experience of an LA-HLH case series in a predominantly Hispanic population in South Florida. The diagnosis is challenging, often delayed, and the prognosis is dismal in refractory cases despite currently available rescue therapies. Furthermore, we describe for the first time the association between HLH and PTLD ALCL.

Pre-transplant molecular minimal residual disease (MMRD) is associated with inferior outcomes in patients with acute myeloid leukemia undergoing allogeneic stem cell transplantation

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Background: Allogeneic Stem Cell Transplant (alloSCT) continues to be the optimal consolidation strategy for many patients with AML; cytogenetic and molecular abnormalities are known predictors of post-transplant outcomes. There is increasing evidence that Molecular Minimal Residual Disease (MMRD) following induction has important prognostic implications and its value in the prediction of post-transplant relapse continues to be elucidated. We aim to evaluate the impact of genetics and pre-transplant MMRD on clinical outcomes following alloSCT. Methods: We retrospectively evaluated eighty-nine patients, ≥18 years with a diagnosis of AML in complete morphologic remission (i.e. < 5% BM blasts by morphologic assessment) who received alloSCT between 01/2012-05/2018 at the University of Miami and for whom cytogenetic and comprehensive molecular data was available prior to transplantation. Patients were stratified into favorable, intermediate and poor-risk categories based on 2017 ELN criteria. MMRD was defined as persistent leukemia-specific mutations prior to transplantation (i.e. NPM1, FLT3, CEBPA, IDH1-2, RUNX1 and TP53). Persistence of DTA mutations (DNMT3A, TET2 and ASXL1) was not considered MMRD, patients with unavailable cytogenetic/molecular data at diagnosis were excluded. Results: Seventy-four (83%) patients were transplanted in CR1, myeloablative conditioning was used in 72% of patients. Two-year OS and LFS were 69.4% and 78.2%, respectively. Stratification by ELN criteria resulted in prognostic separation for patients transplanted in CR1: 2-year OS for favorable (87%), intermediate (68%) and adverse risk (51%) patients (p = 0.0417). The presence of MMRD was the strongest predictor of post-transplant outcomes for the whole cohort with 2-year OS and LFS of 29.4% and 37.1% (HR 5.45 [95%CI 2.43-12.3] p = 0.0001; HR 12.4 [95%CI: 3.76 to 39.8] p = 0.0001); respectively. Subgroup analysis confirmed that MMRD was associated with significantly inferior LFS for IM/favorable and adverse risk patients (HR: 6.76 [95% CI 1.12 to 40.9], p = 0.038). Conclusions: Pre-transplant MMRD was the most important prognostic factor for relapse and survival in our cohort of AML patients undergoing alloSCT. Correlation of MMRD with other transplant variables such as conditioning intensity, MRD status by MFC and the impact of pre-emptive/therapeutic strategies in high-risk patients continues to be explored.

Retreatment (reTx) of patients (pts) with refractory large B-cell lymphoma with axicabtagene ciloleucel (axi-cel) in ZUMA-1

8012

Background: Axi-cel, an autologous anti-CD19 chimeric antigen receptor (CAR) T cell therapy, is approved in the US and EU for pts with relapsed/refractory large B cell lymphoma after ≥ 2 prior therapies. In the ZUMA-1 pivotal study (NCT02348216), the objective response rate (ORR) was 83% (58% complete response [CR] rate; Locke et al. Lancet Oncol. 2019). While axi-cel has demonstrated durable responses in a subset of pts, approximately half of all responders relapsed, and little is known on the viability of reTx with CAR T cell therapy. Here we report outcomes of pts retreated with axi-cel in ZUMA-1. Methods: Pts with progressive disease (PD) were eligible for reTx if there was no evidence of CD19 loss by local review, and if during 1st Tx they did not experience any dose-limiting toxicities, as defined in Phase 1, or comparable toxicities in Phase 2. Pts received the same regimen at reTx as at 1st Tx: 2 × 106 CAR T cells/kg after conditioning chemotherapy. Results: Thirteen pts in Cohorts 1 – 4 received axi-cel reTx. Prior to 1st Tx, most pts (69%) had an IPI score 3-4, 85% had disease stage 3-4, and the median number of prior regimens was 3 (range, 2 – 6). At first Tx, 6 pts achieved a CR, 6 achieved partial response (PR), and 1 pt had stable disease (SD) prior to PD. Median duration of first response was 96 days (range, 56 – 274). There was no Grade ≥ 3 cytokine release syndrome (CRS; 6 pts each had Grade 1 and 2). There were no Grade 4 or 5 neurologic events (NEs; 2 pts had Grade 1, 1 had Grade 2, and 7 had Grade 3). Upon reTx, 54% of pts achieved response (4 CR, 3 PR). Response to reTx was more common among pts who achieved CR at 1st Tx (83%; 4/6 CR, 1 PR, 1 SD) than in pts who achieved PR at 1st Tx (33%; 2/6 PR, 1 SD, 3 PD), and no response was observed in the pt with SD at 1st Tx. Median duration of response at reTx was 81 days (range, 1 – 225+). Response with reTx was longer than that with 1st Tx for 2 pts. One pt remains in response 255 days post-reTx. Comparable rates of CRS were observed with reTx as with 1st Tx. Compared with 1st Tx, fewer pts experienced NEs with reTx, and those that did occur were of lower grade: 23% (3 of 13 pts) had Grade 3; 23% (3 of 13 pts) had Grade 1, and 8% (1 of 13 pts) had Grade 2. Peak CAR T cell expansion was lower upon reTx vs 1st Tx (median, 4.3 vs 66.1 CAR gene-marked cells/µL blood). Conclusions: Based on this limited sample size, reTx with axi-cel may have clinical efficacy, although transient, in some pts, especially those who achieve CR with 1st Tx. CAR T cell expansion and severe CRS and NEs may be attenuated at reTx. Further studies with additional pts are needed to confirm these results. Clinical trial information: NCT02348216 .

Progressive multifocal leukoencephalopathy after CAR T therapy

Progressive multifocal leukoencephalopathy (PML) remains a life-threatening central nervous system infection in immunocompromised patients. Although outcomes have improved in cases that immune reconstitution is feasible with anti-retroviral therapy (ART) in HIV + patients or natalizumab removal in those with multiple sclerosis, in individuals with hematological malignancies, the prognosis is usually dismal. Anti-viral treatments have been largely ineffective, but immunotherapy-based approaches with checkpoint inhibitors and adoptive virus-specific T cells' transfer are currently explored in clinical trials. PML has not been described as a cause of encephalopathy after CAR T therapy. We report the first case of PML 7 months after lymphodepleting chemotherapy with fludarabine/cyclophosphamide and anti-CD19-directed CAR T therapy in a patient with relapsed diffuse large B-cell lymphoma who relapsed fast after a previous autologous hematopoietic stem cell transplant. She remains alive 12 months after diagnosis with stabilization of her symptoms with a combination of therapies targeting viral replication and immunotherapy.

The Role of Autologous Stem Cell Transplantation in the Treatment of Diffuse Large B-cell Lymphoma in the Era of CAR-T Cell Therapy

For many years now and based on the results of the PARMA trial, relapsed Diffuse Large B-cell Lymphoma (DLBCL) is treated with salvage combination cytotoxic chemotherapy (most often platinum-based) followed by high dose myeloablative chemotherapy and autologous stem cell transplantation (auto-HCT). This approach has resulted in long-term disease free survival in about half of the patients. With the incorporation of rituximab in the upfront treatment (RCHOP), more patients with DLBCL are cured but there has been a signal of inferior outcomes with auto-HCT if DLBCL relapses. Nevertheless, a careful review of the literature still shows very good outcomes with auto-HCT for DLBCL with complete remission to salvage chemotherapy. For those who do not respond well to classic salvage other approaches are reviewed here including chimeric antigen receptor (CAR) T-cell therapy and treatment with antibody-drug conjugates (ADCs) as well as bispecific T-cell engagers (BiTEs). The outcome of auto-HCT after successful treatment with ADCs or BITEs is unknown. It is also unknown if CAR-T cell therapy should be reserved for those who have failed 2 lines of chemotherapy or it should be moved earlier. Finally, we review here the effects of Myc and bcl2 amplifications or translocations to the outcome of the auto-HCT. Some attempts to improve the salvage or conditioning regimens are mentioned. We also discuss the role of allogeneic stem cell transplantation (allo-HCT) in the paradigm of treatment for relapsed DLBCL.

Long-term safety and activity of axicabtagene ciloleucel in refractory large B-cell lymphoma (ZUMA-1): a single-arm, multicentre, phase 1-2 trial

BACKGROUND

Axicabtagene ciloleucel is an autologous anti-CD19 chimeric antigen receptor (CAR) T-cell therapy. In the previous analysis of the ZUMA-1 registrational study, with a median follow-up of 15·4 months (IQR 13·7-17·3), 89 (82%) of 108 assessable patients with refractory large B-cell lymphoma treated with axicabtagene ciloleucel achieved an objective response, and complete responses were noted in 63 (58%) patients. Here we report long-term activity and safety outcomes of the ZUMA-1 study.

METHODS

ZUMA-1 is a single-arm, multicentre, registrational trial at 22 sites in the USA and Israel. Eligible patients were aged 18 years or older, and had histologically confirmed large B-cell lymphoma-including diffuse large B-cell lymphoma, primary mediastinal B-cell lymphoma, and transformed follicular lymphoma-according to the 2008 WHO Classification of Tumors of Hematopoietic and Lymphoid Tissue; refractory disease or relapsed after autologous stem-cell transplantation; an Eastern Cooperative Oncology Group performance status of 0 or 1; and had previously received an anti-CD20 monoclonal antibody containing-regimen and an anthracycline-containing chemotherapy. Participants received one dose of axicabtagene ciloleucel on day 0 at a target dose of 2 × 10⁶ CAR T cells per kg of bodyweight after conditioning chemotherapy with intravenous fludarabine (30 mg/m² body-surface area) and cyclophosphamide (500 mg/m² body-surface area) on days -5, -4, and -3. The primary endpoints were safety for phase 1 and the proportion of patients achieving an objective response for phase 2, and key secondary endpoints were overall survival, progression-free survival, and duration of response. Pre-planned activity and safety analyses were done per protocol. ZUMA-1 is registered with ClinicalTrials.gov, number NCT02348216. Although the registrational cohorts are closed, the trial remains open, and recruitment to extension cohorts with alternative endpoints is underway.

FINDINGS

Between May 19, 2015, and Sept 15, 2016, 119 patients were enrolled and 108 received axicabtagene ciloleucel across phases 1 and 2. As of the cutoff date of Aug 11, 2018, 101 patients assessable for activity in phase 2 were followed up for a median of 27·1 months (IQR 25·7-28·8), 84 (83%) had an objective response, and 59 (58%) had a complete response. The median duration of response was 11·1 months (4·2-not estimable). The median overall survival was not reached (12·8-not estimable), and the median progression-free survival was 5·9 months (95% CI 3·3-15·0). 52 (48%) of 108 patients assessable for safety in phases 1 and 2 had grade 3 or worse serious adverse events. Grade 3 or worse cytokine release syndrome occurred in 12 (11%) patients, and grade 3 or worse neurological events in 35 (32%). Since the previous analysis at 1 year, additional serious adverse events were reported in four patients (grade 3 mental status changes, grade 4 myelodysplastic syndrome, grade 3 lung infection, and two episodes of grade 3 bacteraemia), none of which were judged to be treatment related. Two treatment-related deaths (due to haemophagocytic lymphohistiocytosis and cardiac arrest) were previously reported, but no new treatment-related deaths occurred during the additional follow-up.

INTERPRETATION

These 2-year follow-up data from ZUMA-1 suggest that axicabtagene ciloleucel can induce durable responses and a median overall survival of greater than 2 years, and has a manageable long-term safety profile in patients with relapsed or refractory large B-cell lymphoma.

FUNDING

Kite and the Leukemia & Lymphoma Society Therapy Acceleration Program.

Abstract LB-016: Characteristics of the pretreatment tumor microenvironment may influence clinical response in patients with refractory large B cell lymphoma treated with axicabtagene ciloleucel (axi-cel) in the pivotal ZUMA-1

Introduction: Axicabtagene ciloleucel (axi-cel) is an autologous anti-CD19 CAR T cell therapy approved by the US Food and Drug Administration for patients with relapsed or refractory large B cell lymphoma with ≥2 prior systemic therapies. Results from the primary analysis of ZUMA-1 demonstrated an objective response rate of 82%, with 54% complete responses (Neelapu & Locke et al. N Engl J Med. 2017). Grade ≥3 cytokine release syndrome and neurologic events occurred at 13% and 28%, respectively, and were generally reversible. Building on previous reports of CAR treatment-related tumor microenvironment (TME) changes (Galon et al. ASCO 2017. #3025), here, we examine associations between the pretreatment TME and clinical outcomes.

Methods: Patients received axi-cel (target dose, 2.0 × 106 cells/kg) in phases 1 and 2 of ZUMA-1 (NCT02348216). Baseline tumor biopsy samples were analyzed by digital gene expression (NanoStringTM). Prespecified bioinformatics algorithm and cutoffs were applied to immune-mediated tumor regression genes (Immunosign®; Galon et al. Immunity. 2013), which included T cell-specific (effector T cell, Th1) genes, interferon pathway-related genes, chemokines, cytokines, and immune checkpoints. Expression analysis and scoring examined potential associations between TME features and response. A broader, hypothesis-generating analysis was performed using all PanCancer Immune Profiling Panel genes (770 genes) by NanoStringTM. Fisher's exact test and Wilcoxon signed rank test with multiple test correction by false discovery rate (Benjamini-Hochberg) were used.

Results: Tumor samples from all immediate pre-treatment biopsy samples that passed quality control (6 nonresponders; 21 responders) were analyzed. Pretreatment TME Immunosign21 scores were elevated in responders vs nonresponders. Responses were seen in 18/20 patients (90%) with high and 3/7 patients (43%) with low Immunosign21 scores. Immune-related genes from the Immunosign21 or Pan Cancer profile that showed higher expression at baseline in responders included CTLA4, CD3γ, CD3ϵ, CD27, and ICOSL. Genes with lower expression in responders at baseline included MHC class II genes and cancer-testis antigens. Additional correlative analyses between TME characteristics and CAR T cell activity will be presented.

Conclusions: Increased baseline expression of TME genes related to T cell activity, along with decreased expression of MHC class II and cancer testis antigens (CTAs), may be associated with a response to axi-cel. These findings should be validated in ongoing and subsequent studies.

Citation Format: John M. Rossi, Jerome Galon, Sarah Turcan, Corinne Danan, Frederick L. Locke, Sattva S. Neelapu, David B. Miklos, Caron A. Jacobson, Lazaros J. Lekakis, Yi Lin, Armin Ghobadi, William Y. Go, Adrian Bot. Characteristics of the pretreatment tumor microenvironment may influence clinical response in patients with refractory large B cell lymphoma treated with axicabtagene ciloleucel (axi-cel) in the pivotal ZUMA-1 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr LB-016.

Axicabtagene Ciloleucel CAR T-Cell Therapy in Refractory Large B-Cell Lymphoma

BACKGROUND

In a phase 1 trial, axicabtagene ciloleucel (axi-cel), an autologous anti-CD19 chimeric antigen receptor (CAR) T-cell therapy, showed efficacy in patients with refractory large B-cell lymphoma after the failure of conventional therapy.

METHODS

In this multicenter, phase 2 trial, we enrolled 111 patients with diffuse large B-cell lymphoma, primary mediastinal B-cell lymphoma, or transformed follicular lymphoma who had refractory disease despite undergoing recommended prior therapy. Patients received a target dose of 2×106 anti-CD19 CAR T cells per kilogram of body weight after receiving a conditioning regimen of low-dose cyclophosphamide and fludarabine. The primary end point was the rate of objective response (calculated as the combined rates of complete response and partial response). Secondary end points included overall survival, safety, and biomarker assessments.

RESULTS

Among the 111 patients who were enrolled, axi-cel was successfully manufactured for 110 (99%) and administered to 101 (91%). The objective response rate was 82%, and the complete response rate was 54%.With a median follow-up of 15.4 months, 42% of the patients continued to have a response, with 40% continuing to have a complete response. The overall rate of survival at 18 months was 52%. The most common adverse events of grade 3 or higher during treatment were neutropenia (in 78% of the patients), anemia (in 43%), and thrombocytopenia (in 38%). Grade 3 or higher cytokine release syndrome and neurologic events occurred in 13% and 28% of the patients, respectively. Three of the patients died during treatment. Higher CAR T-cell levels in blood were associated with response.

CONCLUSIONS

In this multicenter study, patients with refractory large B-cell lymphoma who received CAR T-cell therapy with axi-cel had high levels of durable response, with a safety profile that included myelosuppression, the cytokine release syndrome, and neurologic events. (Funded by Kite Pharma and the Leukemia and Lymphoma Society Therapy Acceleration Program; ZUMA-1 ClinicalTrials.gov number, NCT02348216 .).

Impact of Cytomegalovirus Viral Load on Probability of Spontaneous Clearance and Response to Preemptive Therapy in Allogeneic Stem Cell Transplantation Recipients

The optimal viral load threshold at which to initiate preemptive cytomegalovirus (CMV) therapy in hematopoietic cell transplantation (HCT) recipients remains to be defined. In an effort to address this question, we conducted a retrospective study of 174 allogeneic HCT recipients who underwent transplantation at a single center between August 2012 and April 2016. During this period, preemptive therapy was initiated at the discretion of the treating clinician. A total of 109 patients (63%) developed CMV viremia. The median time to reactivation was 17 days (interquartile range, IQR, 7-30 days) post-HCT. A peak viremia ≥150 IU/mL was strongly associated with a reduced probability of spontaneous clearance (relative risk, .16; 95% confidence interval, .1-.27), independent of established clinical risk factors, including CMV donor serostatus, exposure to antithymocyte globulin, and underlying lymphoid malignancy. The median time to clearance of viremia was significantly shorter in those who started therapy at CMV <350 IU/mL (19 days; IQR, 11-35 days) compared with those who started antiviral therapy at higher viremia thresholds (33 days; IQR, 21-42 days; P = .02). The occurrence of treatment-associated cytopenias was frequent but similar in patients who started preemptive therapy at CMV <350 IU/mL and those who started at CMV >350 IU/mL (44% versus 57%; P = .42). Unresolved CMV viremia by treatment day 35 was associated with increased risk of therapeutic failure (32% versus 0%; P = .001). Achieving eradication of CMV viremia by treatment day 35 was associated with a 74% reduction in 1-year nonrelapse mortality (NRM) (adjusted hazard ratio [HR], .26; 95% confidence interval [CI], .1-.8; P = .02), whereas therapeutic failure was associated with a significant increase in the probability of 1-year NRM (adjusted HR, 26; 95% CI, 8-87; P <.0001). We conclude that among allogeneic HCT patients, a peak CMV viremia ≥150 IU/mL is associated with a >80% reduction in the probability of spontaneous clearance independent of ATG administration, CMV donor serostatus, and lymphoid malignancy, and is a reasonable cutoff for preemptive therapy. Delaying initiation of therapy until a CMV value ≥350 IU/mL is associated with more protracted CMV viremia, and unresolved viremia by treatment day 35 is associated with a significant increase in NRM.

Product characteristics associated with in vivo expansion of anti-CD19 CAR T cells in patients treated with axicabtagene ciloleucel (axi-cel)

3023

Background: Axi-cel (formerly KTE-C19) is an autologous anti-CD19 chimeric antigen receptor (CAR) T cell therapy. ZUMA-1 is a multicenter, registrational trial of axi-cel in patients (pts) with refractory aggressive non-Hodgkin lymphoma. In a prespecified interim analysis, ZUMA-1 met its primary endpoint, with a 76% objective response rate and a 47% complete response rate ( Blood 2016;128:LBA-6). Post-treatment CAR T cell blood levels were associated with objective response. Here, we describe novel associations between product characteristics and CAR T cell levels in pts. Methods: CAR T cell characteristics in axi-cel produced from 62 pts were analyzed by flow cytometry and modeled against CAR T cell levels. In vivo CAR T cell levels were measured by qPCR. T cell expansion during production (fold expansion/total days in culture) was compared with CAR T cell blood levels, using a partition analysis with expansion rates of ≥1 vs < 1. Wilcoxon 2-sample test and linear regression were used. Results: Axi-cel contained CCR7+ T cells (median, 42%; range, 15–73%), with naïve (CD45RA+/CCR7+; median, 12%; range, 1–57%), central memory (CD45RA−/CCR7+; median, 29%; range, 12–49%) phenotypes, and more differentiated CCR7− effector memory and effector T cells. On infusion, CAR T cells expanded rapidly, reaching peak levels within 2 weeks (median, 43 cells/μL; range, 1–1513), and were also measurable in all pts at 1 month (median, 2 cells/μL; range, 0.03–89). The CCR7+/CCR7− T cell ratio in axi-cel associated positively with peak ( P =0.001) and cumulative ( P =0.003) CAR T cell levels through 1 month. Axi-cel lots that expanded more rapidly during production (≥1.0-fold/d; n = 18/62) associated with higher cumulative levels of CAR T cells ( P =0.03). Other product characteristics, eg, CD4/CD8 ratio or number of infused T cells, were not significantly associated with CAR T cell blood levels. Conclusions: An association was observed between CAR T cell expansion in vivo and both the T cell growth rate during production and product cell phenotype pretreatment. A key attribute of axi-cel product was the presence of CCR7+ naïve/central memory T cells, without upfront T cell subset selection. Clinical trial information: NCT02348216.

Clinical and biologic covariates of outcomes in ZUMA-1: A pivotal trial of axicabtagene ciloleucel (axi-cel; KTE-C19) in patients with refractory aggressive non-Hodgkin lymphoma (r-NHL)

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Background: Outcomes in activated B cell subtype diffuse large B cell lymphoma (ABC-DLBCL) and r-NHL are poor (Sehn Blood 2015, Crump ASCO 2016). ZUMA-1 is the first, multicenter trial of anti-CD19 chimeric antigen receptor (CAR) T cells, axi-cel, in r-NHL. Methods: Dosing and eligibility were per Neelapu ASH 2016. The primary endpoint was objective response rate (ORR); secondary endpoints were duration of response (DOR), overall survival (OS), and safety. Cell of origin (COO) and CD19 status were assessed centrally using Lymphoma Subtyping Test NanoString (Wallden JCO 2015) and a validated immunohistochemistry assay, respectively. Results: As of Jan 27, 2017, 111 patients (pts) were enrolled; the manufacturing success rate was 99% with an average 17-d turnaround time; 101 pts (modified intent-to-treat [mITT] population) received axi-cel. In the mITT population, the ORR was 82% (complete response [CR], 54%). With 8.7 m median follow-up, 44% remain in response and 39% in CR. The median DOR was 8.1 m and not reached (NR) for pts with CR. Median OS was NR. Results for clinical and biologic covariates are listed in the table. In pts who received tocilizumab (n = 43) and/or steroids (n = 27) for cytokine release syndrome (CRS) and/or neurologic events (NE), ORR was 84% and 78%, respectively. Most common grade ≥3 adverse events (AEs) were neutropenia (66%), leukopenia (44%), anemia (43%), febrile neutropenia (31%), thrombocytopenia (24%), and encephalopathy (21%). Rates of grade ≥3 CRS and NE were 13% and 28%, respectively. There were 3 grade 5 AEs (Neelapu ASH 2016). Conclusions: Axi-cel induced an ORR of 82% in pts with r-NHL, response is ongoing in 44% of pts at 8.7 m. Similar clinical responses were observed in pts with r-ABC-DLBCL. AEs were manageable and the use of tocilizumab/steroids did not appear to impact ORR. Drs Locke and Neelapu contributed equally. Funding source: Kite Pharma and Leukemia & Lymphoma Society Therapy Acceleration Program Clinical trial information: NCT02348216. [Table: see text]