Impact of tumor microenvironment on efficacy of anti-CD19 CAR T cell therapy or chemotherapy and transplant in large B cell lymphoma

The phase 3 ZUMA-7 trial in second-line large B cell lymphoma demonstrated superiority of anti-CD19 CAR T cell therapy (axicabtagene ciloleucel (axi-cel)) over standard of care (SOC; salvage chemotherapy followed by hematopoietic transplantation) ( NCT03391466 ). Here, we present a prespecified exploratory analysis examining the association between pretreatment tumor characteristics and the efficacy of axi-cel versus SOC. B cell gene expression signature (GES) and CD19 expression associated significantly with improved event-free survival for axi-cel (P = 0.0002 for B cell GES; P = 0.0165 for CD19 expression) but not SOC (P = 0.9374 for B cell GES; P = 0.5526 for CD19 expression). Axi-cel showed superior event-free survival over SOC irrespective of B cell GES and CD19 expression (P = 8.56 × 10-9 for B cell GES high; P = 0.0019 for B cell GES low; P = 3.85 × 10-9 for CD19 gene high; P = 0.0017 for CD19 gene low). Low CD19 expression in malignant cells correlated with a tumor GES consisting of immune-suppressive stromal and myeloid genes, highlighting the inter-relation between malignant cell features and immune contexture substantially impacting axi-cel outcomes. Tumor burden, lactate dehydrogenase and cell-of-origin impacted SOC more than axi-cel outcomes. T cell activation and B cell GES, which are associated with improved axi-cel outcome, decreased with increasing lines of therapy. These data highlight differences in resistance mechanisms to axi-cel and SOC and support earlier intervention with axi-cel.

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.

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.

Abstract 2366: HDAC inhibition improves immune checkpoint inhibitor efficacy in renal cell carcinoma

Background: Immune checkpoint inhibitors have shown clinical benefit in solid tumors, including renal cell carcinoma (RCC); however, the rate of clinical response remains modest and improved therapeutic approaches need to be tested. Growing evidence suggests that epigenetic modifying agents may have an immunomodulatory effect that improves the efficacy of immune checkpoint inhibitors. Our group has previously demonstrated that entinostat, a histone deacetylase (HDAC) inhibitor, decreases the function of regulatory T cells (Treg) and myeloid derived suppressor cells (MDSC), synergizing with PD-1 blockade. Here we assessed the combination of PD-1 blockade with pan-HDAC inhibition in a RCC model.

Methods: To test the efficacy of combined PD-1 inhibition, mDX-400 (10 and 20 mg/kg I.P) (Merck & Co, Inc) with pan-HDAC inhibition, vorinostat (100 and 150 mg/kg I.P) (Merck & Co, Inc), we utilized a syngeneic mouse model of metastatic RCC following orthotopic implantation of RENCA cells in immunocompetent mice. Antitumor activity was assessed by measuring bioluminescence, end point tumor weights, and survival times. Immune profiling of tumor infiltrating lymphocytes (TILs) was performed by flow cytometry, immunohistochemistry, and immunofluorescence. Peripheral blood mononuclear cells (PBMC) were assessed for differential chromatin accessibility by Assay for Transposase-Accessible Chromatin with high-throughput sequencing (ATAC-seq).

Results: Significant reductions in tumor weight and lung metastases were observed in mice treated with the combination of vorinostat and mDX-400. Combination therapy significantly increased the survival of the mice (median survival = 60) compared to treatment with mDX-400 alone (median survival=42 days). Immune landscape profiling demonstrated an increase in natural killer cell infiltration (P=0.048) and decrease of exhausted T cells (P=0.049, CD8+ PD1+) in the combination group. Furthermore, decreased immunosuppressive Treg (CD4+ FOXP4+) and MDSC (CD11b+ Gr1+) populations were identified in the combination group. Analysis of the mouse PBMC ATAC-seq data in the combination and mDX400 alone conditions demonstrated numerous regions of differential chromatin accessibility. Pathway analysis of genes associated with increased accessibility in the combination treatment identified enrichment of cell cycle and immune activation pathways.

Conclusions: Our results demonstrate that pan-HDAC inhibition augments the antitumor effect of immune checkpoint inhibitors, prolonging survival in our preclinical mouse model. This antitumor effect was achieved by changing the immune landscape in TILs and was associated with higher chromatin accessibility near genes involved in cell cycle progression and immune cell activation. Taken together, our results support the clinical testing of pan-HDAC inhibitors in combination with anti-PD-1.

Citation Format: Justin Budka, Nur Damayanti, Roberto Pili. HDAC inhibition improves immune checkpoint inhibitor efficacy in renal cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2366.

Abstract 1611: Caloric restriction potentiates the therapeutic benefit of androgen deprivation therapy and alters macrophage polarization when combined with PD1 inhibition in murine models of prostate cancer

Background: Data from epidemiological studies have linked dietary intake to the development of prostate cancer (CaP). We have previously shown that dietary protein restriction inhibits tumor growth by modulating PI3K/mTOR signaling in vivo. Additionally we have shown that dietary methionine restriction influence macrophage polarization which enhances the ability of the immune system to fight cancer. In this study we hypothesize that caloric restriction is capable of restricting tumor growth and potentiating the antitumor effect of androgen deprivation therapy (ADT) and PD1 inhibition.

Methods: We utilized two prostate cancer models for our in vivo studies; castrate resistant LuCaP 23.1 AI prostate cancer model and MYC-Driven prostate cancer model in C57BL/6 mice. Caloric restriction was carried out by exposing mice to alternating fasting either as a single intervention (in LuCaP 23.1 model) or in combination with ADT (enzalutamide or surgical castration) or PD-1 inhibition in Myc-CaP model. Tumor sizes and weights were blindly assessed during the study and upon study termination respectively. IHC staining for both Ki-67 and mTOR phosphorylation was done to assess the impact of fasting+/- ADT on tumor growth and mTOR signaling. Macrophage polarization/distribution in tumors was assessed using immunofluorescence. Blood was collected at the end of the study for future comprehensive analysis of PBMCS.

Results: In both models, alternating fasting was associated with significant decrease in tumor weight at the end of study in comparison to control group (*p<0.05). In Myc-CaP model, tumor weight was significantly decreased in combined fasting and enzalutamide/castration group in comparison to the control condition (**p<0.001) but was not significantly better than either intervention alone. Similarly, fasting potentiated the therapeutic benefit of PD-1 inhibition yet it was not significant. Combined fasting and ADT was associated with significant reduction in Ki-67 nuclear expression (****p<0.0001), however it was not significantly less than either agent alone. Combined fasting and ADT was associated with significant decrease in P-mTOR expression in comparison to control mice (****p<0.0001). Although we did not observe significant change in tumor weight with combined fasting and PD-1 inhibition; fasting potentiated the influence of PD-1 on macrophage polarization. M2 macrophages were significantly less in combined treatment compared to either single intervention alone (**p<0.01).

Conclusions: Caloric restriction can hinder prostate cancer growth and potentiate the therapeutic effect of ADT. Our results provide basis for the translational use of dietary modification both as preventive measure as well as a therapeutic intervention that can improve the benefit of current standard treatments.

Citation Format: May Elbanna, Justin Budka, Paige Dausinas, Remi Adelaiye-Ogala, Nur Damayanti, Ashley Orillion, Eri Banno, Luigi Fontana, Roberto Pili. Caloric restriction potentiates the therapeutic benefit of androgen deprivation therapy and alters macrophage polarization when combined with PD1 inhibition in murine models of prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1611.

Immunomodulation by HDAC inhibition: Results from a phase Ib study with vorinostat and pembrolizumab in metastatic urothelial, renal, and prostate carcinoma patients

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Background: Immunosuppressive factors such as regulatory T cells (Tregs) and myeloid-derived suppressive cells (MDSCs) limit the efficacy of immunotherapies. Histone deacetylase (HDAC) inhibitors have been shown to have immunomodulatory effects. We have previously reported that HDAC inhibitors have synergistic antitumor effects in combination with PD-1 inhibition in tumor models by inhibiting the function of Tregs and MDSCs. Thus, we conducted a Phase Ib clinical study with the HDAC inhibitor vorinostat and the PD-1 inhibitor pembrolizumab in patients (pts) with metastatic urothelial, renal and prostate carcinoma. Methods: The primary objective was to evaluate the safety and tolerability of this combination strategy. The phase I portion consisted of two dose levels of vorinostat (100 and 200 mg, PO daily 2 weeks ON and one week OFF) and a fixed, standard dose of pembrolizumab (200 mg IV every 21 days). Patients were assigned to three cohorts: Cohort A (previously treated, anti-PD1/PD-L1 naïve urothelial and renal cancer pts = 15), Cohort B (previously treated, anti-PD1/PD-L1 resistant urothelial and renal cancer pts = 14), and Cohort C (prostate cancer pts = 14). Results: Dose levels 1 (4 enrolled, 3 evaluable) and 2 (4 enrolled, 3 evaluable) were completed without DLTs and 200 mg was the Phase II recommended dose for vorinostat. The most common resolved grade 3/4 toxicities were acute kidney injury (n = 1), anemia (n = 1), diarrhea (n = 1), and hypothyroidism (n = 1) in the dose expansion cohorts. We have enrolled 43 pts (37 evaluable) in the dose expansion cohorts. For Cohort A, B, and C the median PFS were 2.8 months, 5.2 months, and 3.5 months. Two PR were observed including the dose escalation phase. Two PCA pts have achieved undetectable PSA. We have performed several correlative studies including flow cytometry and gene expression analysis on peripheral blood mononuclear cells, PDL-1 staining and PSMA PET scans in a subset of pts. Conclusions: The results from this phase Ib suggest that the combination of vorinostat and pembrolizumab is relatively well tolerated and may be active in a subset of immune checkpoint resistant UC/RCC pts and immune checkpoint naïve PCA pts. Clinical trial information: NCT02619253.

EZH2 Modifies Sunitinib Resistance in Renal Cell Carcinoma by Kinome Reprogramming

Acquired and intrinsic resistance to receptor tyrosine kinase inhibitors (RTKi) represents a major hurdle in improving the management of clear cell renal cell carcinoma (ccRCC). Recent reports suggest that drug resistance is driven by tumor adaptation via epigenetic mechanisms that activate alternative survival pathways. The histone methyl transferase EZH2 is frequently altered in many cancers, including ccRCC. To evaluate its role in ccRCC resistance to RTKi, we established and characterized a spontaneously metastatic, patient-derived xenograft model that is intrinsically resistant to the RTKi sunitinib, but not to the VEGF therapeutic antibody bevacizumab. Sunitinib maintained its antiangiogenic and antimetastatic activity but lost its direct antitumor effects due to kinome reprogramming, which resulted in suppression of proapoptotic and cell-cycle-regulatory target genes. Modulating EZH2 expression or activity suppressed phosphorylation of certain RTKs, restoring the antitumor effects of sunitinib in models of acquired or intrinsically resistant ccRCC. Overall, our results highlight EZH2 as a rational target for therapeutic intervention in sunitinib-resistant ccRCC as well as a predictive marker for RTKi response in this disease. Cancer Res; 77(23); 6651-66. ©2017 AACR.

Application of RDC enhanced NMR spectroscopy in structural analysis of thiacalix[4]arene derivatives

The conformational behaviour of novel phenoxathiin-based skeletons was studied using the Residual Dipolar Coupling constant (RDC) method.