Pretreatment Tumor Microenvironment Research Articles

Abstract 1211: Biomarker analysis of pembrolizumab and ramucirumab neoadjuvant therapy for PD-L1-positive stage IB-IIIA lung cancer: EAST ENERGY trial

Abstract Background: Neoadjuvant treatments with novel combination immunotherapies for resectable non-small cell lung cancer (NSCLC) are being developed. Combination therapy with antiangiogenic agents and anti-PD-1/PD-L1 antibody has shown enhanced antitumor effects. EAST ENERGY is a single-arm multicenter phase 2 trial of neoadjuvant pembrolizumab and ramucirumab in patients with PD-L1-positive stage IB-IIIA NSCLC (NCT04040361). In this study, we aimed to identify biomarkers that predicts the efficacy of the neoadjuvant therapy. Furthermore, we aimed to elucidate the effect of the neoadjuvant therapy on the tumor microenvironment (TME). Methods: Patients enrolled in the EAST ENERGY trial (n=24) for whom pre- and post-treatment specimens were available (n=20) were included in this study. RNA-sequencing and multiplex immunohistochemistry (mIHC) were used to examine the association between the immunological phenotype of the TME and major pathological response (MPR), and changes in the TME before and after treatment. Results: MPR was achieved in 50.0% (12/24) of patients. Biomarker analyses with RNA-sequencing revealed that high expression of cancer-associated genes, and upregulation of interferon-gamma and interferon-alpha response in pre-treatment tumor were associated with MPR (q value<0.001). mIHC in pre-treatment samples revealed that abundance of CD8+ T cells in the pre-treatment TME was associated with MPR (p=0.039). On the other hand, infiltration of immunosuppressive cells such as Treg or M2-macrophages were not associated with resistance for the treatment (p=0.836, 0.639, respectively). Next, to clarify the effect of the neoadjuvant therapy on the TME, comparative analyses of pre- and post-treatment samples was performed. In gene set enrichment analysis, the neoadjuvant therapy enhanced gene set associated with interferon-gamma response (q value=0.051). Furthermore, angiogenesis-related gene set were downregulated after the treatment (q value=0.090). mIHC analyses revealed that the number of CD8+ T cells in the TME was significantly increased after the neoadjuvant therapy (p<0.001). Notably, Tregs/CD8+ T cells ratio and the number of M2-macrophage in the TME were significantly decreased after the neoadjuvant therapy (p=0.032, 0.003, respectively). Conclusion: In the neoadjuvant therapy with pembrolizumab and ramucirumab, immune-activated status before treatment serves as a potential biomarker for predicting treatment response. Moreover, combining ramucirumab with pembrolizumab reduced immunosuppressive cells in the TME and inhibited tumor angiogenesis. These results suggest that this combination therapy modifies the TME and augments antitumor immunity. Larger clinical trial is warranted to assess the efficacy of neoadjuvant therapy with ramucirumab and pembrolizumab in patients with PD-L1-positive NSCLC. Citation Format: Kotaro Nomura, Shogo Kumagai, Shohei Koyama, Keiju Aokage, Yoshihisa Shimada, Kiyotaka Yoh, Masashi Wakabayashi, Miki Fukutani, Hideki Furuya, Tomohiro Miyoshi, Kenta Tane, Joji Samejima, Tetsuro Taki, Takuo Hayashi, Jun Matsubayashi, Genichiro Ishii, Norihiko Ikeda, Hiroyoshi Nishikawa, Masahiro Tsuboi. Biomarker analysis of pembrolizumab and ramucirumab neoadjuvant therapy for PD-L1-positive stage IB-IIIA lung cancer: EAST ENERGY trial [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1211.

The phosphatidylserine targeting antibody bavituximab plus pembrolizumab in unresectable hepatocellular carcinoma: a phase 2 trial

Immune checkpoint inhibitors targeting PD-1/L1 have modest efficacy in hepatocellular carcinoma as single agents. Targeting membranous phosphatidylserine may induce pro-inflammatory and -immune stimulating effects that enhance immunotherapy activity. This hypothesis was tested in a single-arm phase 2 trial evaluating frontline bavituximab, a phosphatidylserine targeting antibody, plus pembrolizumab (anti-PD-1) in patients with unresectable hepatocellular carcinoma (NCT03519997). The primary endpoint was investigator-assessed objective response rate among evaluable patients, and secondary end points included progression-free survival, incidence of adverse events, overall survival, and duration of response. Among 28 evaluable patients, the confirmed response rate was 32.1%, which met the pre-specified endpoint, and the median progression-free survival was 6.3 months (95% CI, 1.3–11.3 months). Treatment related-adverse events of any grade occurred in 45.7% of patients, with grade 3 or greater adverse events in 14.3% of patients. Adverse events of any cause were observed in 33 patients (94.3%), with grade 3 or greater adverse events in 11 patients (31.4%). Prespecified exploratory analyses of baseline tumor specimens showed that a depletion of B cells, and the presence of fibrotic tissue and expression of immune checkpoints in stroma was associated with tumor response. These results suggest that targeting phosphatidylserine may lead to synergistic effects with PD-1 blockade without increasing toxicity rates, and future studies on this therapeutic strategy may be guided by biomarkers characterizing the pre-treatment tumor microenvironment.

Efficacy and Safety of BCMA-Specific CAR T Cell-Based Therapy in Relapsed/Refractory Multiple Myeloma Patients with Extramedullary Disease

Background Extramedullary disease (EMD) is an aggressive subentity of multiple myeloma (MM), characterized by the ability of a subclone to grow independent of the bone marrow microenvironment, resulting in a high-risk state associated with increased proliferation, evasion of immune surveillance and treatment resistance. Relapsed/refractory multiple myeloma (R/R MM) patients with EMD have unfavorable prognoses and no effective treatment options. B-cell maturation antigen (BCMA)-specific chimeric antigen receptor (CAR) T-cell therapies have shown promising efficacy in R/R MM; however, data on patients with EMD remain limited. We aimed to assess the efficacy and safety of CAR T-cell therapy in R/R MM patients with EMD. Methods We conducted a retrospective multi-institutional study of 55 R/R MM patients confirmed with EMD at referral. The definition of EMD included (1) soft tissue masses in extraosseous locations resulting from hematogenous spread (EM-E) and (2) bone-related plasmacytomas that extend via disruption of cortical bones into contiguous soft tissues (EM-B). The overall response, long-term outcomes, and safety were assessed. We also characterized differential response between medullary and extramedullary disease, analyzed unique attributes of compartmental toxicity, and explored patterns of relapse in the setting of EMD. Gene expression profiling was performed using nCounter Human CAR-T Characterization Panel (NanoString, #XT-CSO-HCART1-12) on 40 biopsy specimens from patients enrolled in this study, including EMD and bone marrow biopsy specimens at pretreatment or/and at relapse. Results were analyzed based on outcome (no durable response [progression within 6 months, NDR] vs durable response [progression beyond 6 months, DR]). Multiplex immunofluorescence (mIF) was performed for detection of populations and phenotyping of infiltrated CD8 + T cells (Panel A: CD8/PD-1/LAG-3/TIM-3) and macrophages (Panel B: CD68/CD86/CD163) with EMD biopsies. Results The infusion resulted in an overall response rate of 90.9% (95% confidence interval [CI], 80.4-96.1) in medullary disease and 70.9% (95% CI, 57.9-81.2) in EMD ( P = 0.008). Discrepant outcomes between medullary and extramedullary response were observed, with suboptimal and delayed overall response and shortened duration of response achieved in EMD. With a median follow-up of 27.3 months, the median progression-free survival was 8.7 months (95% CI, 3.7-18.8), and the median overall survival was 16.0 months (95% CI, 13.5-20.1). Landmark analysis was conducted to compare OS in patients who progressed versus remained progression-free at the 6-month landmark time point. We demonstrated that progression before 6 months post-infusion is strongly associated with an increased risk of death (HR = 11.15 [95% CI, 3.49 to 35.60]; P < 0.001). Local cytokine release syndrome (CRS) was depicted in 21.8% patients and was moderately associated with the occurrence of systemic CRS (r = 0.322; P = 0.017). 78.2% patients experienced post-infusion progression in EMD, and BCMA + progression constituted the main pattern of EMD progression. At the time of EMD progression, peripheral CAR + cells were detectable, and 50% patients had ongoing documented B cell aplasia. We next interrogated NanoString gene expression data of tumor microenvironment (TME) genes for possible association with clinical response and toxicity. Pretreatment TME enriched for immune checkpoint, and type I interferon signaling were associated negatively with clinical outcomes. We found that the infiltration of type 2 macrophages (CD68 +CD163 +) in pretreatment TME is associated with the density of activated or exhausted CD8 + T cell ( PD-1 +LAG-3 +/-), and is associated with no durable response in EMD. We interrogated TME dynamic changes of patients developing EMD progression between cohorts of DR and NDR. An increase in immune counter-regulatory marker and lower diversity of T-cell receptor (TCR) repertoire, was observed at relapse in cohort of NDR. Discussion Our study shows that anti-BCMA CAR-T therapy has provided apparent therapeutic advantage over the existing drugs in response rate and long-term survival. Compared with medullary disease, BCMA-specific CAR T cell-based therapy showed limited and discrepant efficacy in EMD, perhaps due to the the properties of EMD-specific microenvironment.

CD4+ T cells drive an inflammatory, TNF-α/IFN-rich tumor microenvironment responsive to chemotherapy

While chemotherapy remains the first-line treatment for many cancers, it is still unclear what distinguishes responders from non-responders. Here, we characterize the chemotherapy-responsive tumor microenvironment in mice, using RNA sequencing on tumors before and after cyclophosphamide, and compare the gene expression profiles of responders with progressors. Responsive tumors have an inflammatory and highly immune infiltrated pre-treatment tumor microenvironment characterized by the enrichment of pathways associated with CD4+ Tcells, interferons (IFNs), and tumor necrosis factor alpha (TNF-α). The same gene expression profile is associated with response to cyclophosphamide-based chemotherapy in patients with breast cancer. Finally, we demonstrate that tumors can be sensitized to cyclophosphamide and 5-FU chemotherapy by pre-treatment with recombinant TNF-α, IFNγ, and poly(I:C). Thus, a CD4+ Tcell-inflamed pre-treatment tumor microenvironment is necessary for response to chemotherapy, and this state can be therapeutically attained by targeted immunotherapy.

Dual Oxidase 2 (DUOX2) as a Proteomic Biomarker for Predicting Treatment Response to Chemoradiation Therapy for Locally Advanced Rectal Cancer: Using High-Throughput Proteomic Analysis and Machine Learning Algorithm.

High-throughput mass-spectrometry-based quantitative proteomic analysis was performed using formalin-fixed, paraffin-embedded (FFPE) biopsy samples obtained before treatment from 13 patients with locally advanced rectal cancer (LARC), who were treated with concurrent chemoradiation therapy (CCRT) followed by surgery. Patients were divided into complete responder (CR) and non-complete responder (nCR) groups. Immunohistochemical (IHC) staining of 79 independent FFPE tissue samples was performed to validate the predictive ability of proteomic biomarker candidates. A total of 3637 proteins were identified, and the expression of 498 proteins was confirmed at significantly different levels (differentially expressed proteins-DEPs) between two groups. In Gene Ontology enrichment analyses, DEPs enriched in biological processes in the CR group included proteins linked to cytoskeletal organization, immune response processes, and vesicle-associated protein transport processes, whereas DEPs in the nCR group were associated with biosynthesis, transcription, and translation processes. Dual oxidase 2 (DUOX2) was selected as the most predictive biomarker in machine learning algorithm analysis. Further IHC validation ultimately confirmed DUOX2 as a potential biomarker for predicting the response of nCR to CCRT. In conclusion, this study suggests that the treatment response to RT may be affected by the pre-treatment tumor microenvironment. DUOX2 is a potential biomarker for the early prediction of nCR after CCRT.

Multimodality analysis confers a prognostic benefit of a T-cell infiltrated tumor microenvironment and peripheral immune status in patients with melanoma

BackgroundWe previously reported results from a phase 1 study testing intratumoral recombinant poliovirus, lerapolturev, in 12 melanoma patients. All 12 patients received anti-PD-1 systemic therapy before lerapolturev, and 11 of...

Tumor immune contexture is a determinant of anti-CD19 CAR T cell efficacy in large B cell lymphoma

Axicabtagene ciloleucel (axi-cel) is an anti-CD19 chimeric antigen receptor (CAR) T cell therapy approved for relapsed/refractory large B cell lymphoma (LBCL) and has treatment with similar efficacy across conventional LBCL subtypes. Toward patient stratification, we assessed whether tumor immune contexture influenced clinical outcomes after axi-cel. We evaluated the tumor microenvironment (TME) of 135 pre-treatment and post-treatment tumor biopsies taken from 51 patients in the ZUMA-1 phase 2 trial. We uncovered dynamic patterns that occurred within 2 weeks after axi-cel. The biological associations among Immunoscore (quantification of tumor-infiltrating T cell density), Immunosign 21 (expression of pre-defined immune gene panel) and cell subsets were validated in three independent LBCL datasets. In the ZUMA-1 trial samples, clinical response and overall survival were associated with pre-treatment immune contexture as characterized by Immunoscore and Immunosign 21. Circulating CAR T cell levels were associated with post-treatment TME T cell exhaustion. TME enriched for chemokines (CCL5 and CCL22), γ-chain receptor cytokines (IL-15, IL-7 and IL-21) and interferon-regulated molecules were associated with T cell infiltration and markers of activity. Finally, high density of regulatory T cells in pre-treatment TME associated with reduced axi-cel–related neurologic toxicity. These findings advance the understanding of LBCL TME characteristics associated with clinical responses to anti-CD19 CAR T cell therapy and could foster biomarker development and treatment optimization for patients with LBCL.

Tumor microenvironment (TME) dynamics following capecitabine/oxaliplatin (CapeOx) plus pembrolizumab in patients with advanced gastric cancer.

4053 Background: Immune checkpoint inhibition (ICI) has made significant breakthroughs in several tumor types including gastric cancer (GC) in recent years. However, single-agent pembrolizumab demonstrated remarkable and durable response in MSI and EBV GC because they are immune-enriched types. Recently, we reported on-treatment remodeling of the TME during chemotherapy in MSS AGC ( Cancer Discov. 2021). We defined altered features including decreased tumor-associated macrophages (TAM), M1- macrophages repolarization and recruitment of NK cells, effector T cells. Methods: This phase 2, open-label, single-arm study was designed to assess the safety and efficacy of the CapeOx-pembrolizumab combination in advanced gastric cancer patients with HER2-negative. 38 patients were enrolled onto our CapeOx plus Pembrolizumab trial (NCT #04249739). All patients had MSS status with EBV-negative. Endoscopic biopsies were collected at baseline, after 1 cycle of chemotherapy alone and after 4 to 5 cycles of CapeOx + pembrolizumab to understand the impact of treatment to tumor TME. We performed coupling whole exome sequencing and whole transcriptome sequencing. Molecular features were extracted by exonic analysis. TME subtype was estimated by gene expression analysis. Results: Between 2020 and 2021, 38 patients were enrolled. There were 2 CR, 25 PR, 11 SD as best response.First, we found a number of somatic mutations (median 157.5, range 7-25,719) in pre-and on-treatment samples. Despite the creation and destruction of somatic mutation, we observed that ancestor mutations including TP53, MUC6 and APC previously reported in TCGA GC cohort, were preserved. At baseline (before chemotherapy), patients were classified to 5 immune-enriched (IE) subtye, 21 immune-depleted (D) subtype, ETC. Second, we observed a dynamic change following one cycle of CapeOx before the addition of pembrolizumab to chemotherapy. Nine (23.68%) out of thirty eight patients with immune-depleted or fibrotic pre-treatment TME became immune-favorable during treatment. Interestingly, seventeen (58.62%) out of twenty nine patients with immune-unfavorable pre-treatment TME became immune-favorable following CapeOx plus Pembrolizumab chemotherapy. Conclusions: This is the first study to demonstrate TME change during CapeOx plus pembrolizumab at molecular levels and will have clinically meaningful performance in patients with metastatic GC. Clinical trial information: NCT#04249739.

Tumor Immune Microenvironment and Response to Neoadjuvant Chemotherapy in Hormone Receptor/HER2+ Early Stage Breast Cancer

BackgroundPathologic response at the time of surgery after neoadjuvant therapy for HER2 positive early breast cancer impacts both prognosis and subsequent adjuvant therapy. Comprehensive descriptions of the tumor microenvironment (TME) in patients with HER2 positive early breast cancer is not well described. We utilized standard stromal pathologist-assessed tumor infiltrating lymphocyte (TIL) quantification, quantitative multiplex immunofluorescence, and RNA-based gene pathway signatures to assess pretreatment TME characteristics associated pathologic complete response in patients with hormone receptor positive, HER2 positive early breast cancer treated in the neoadjuvant setting. MethodsWe utilized standard stromal pathologist-assessed TIL quantification, quantitative multiplex immunofluorescence, and RNA-based gene pathway signatures to assess pretreatment TME characteristics associated pathologic complete response in 28 patients with hormone receptor positive, HER2 positive early breast cancer treated in the neoadjuvant setting. ResultsPathologist-assessed stromal TILs were significantly associated with pathologic complete response (pCR). By quantitative multiplex immunofluorescence, univariate analysis revealed significant increases in CD3+, CD3+CD8-FOXP3-, CD8+ and FOXP3+ T-cell densities as well as increased immune cell aggregates in pCR patients. In subsets of paired pre/post-treatment samples, we observed significant changes in gene expression signatures in non-pCR patients and significant decreases in CD8+ densities after treatment in pCR patients. No RNA based pathway signature was associated with pCR. ConclusionTME characterization HER2 positive breast cancer patients revealed several stromal T-cell densities and immune cell aggregates associated with pCR. These results demonstrate the feasibility of these novel methods in TME evaluation and contribute to ongoing investigations of the TME in HER2+ early breast cancer to identify robust biomarkers to best identify patients eligible for systemic de-escalation strategies.

Abstract P2-07-09: Characterization of the tumor microenvironment in patients with hormone receptor positive, HER2 negative early breast cancer

Abstract Background: Patients (pts) with early stage HER2+ breast cancer (HER2+ EBC) are often treated with neoadjuvant chemotherapy (NACT). Recent studies have demonstrated that increased densities of tumor infiltrating lymphocytes (TIL) are associated with increased rates of pathologic complete response (pCR) in HER2+ EBC. However, outside of standard TIL analysis, a more comprehensive description of the tumor microenvironment (TME) and its impact on clinical outcomes in HER+ EBC is not well defined. Using novel methods, we sought to characterize the TME of patients with hormone receptor positive (HR+), HER2+ EBC treated with NACT. In addition to standard H&E based TIL analysis, we utilized quantitative multiplex immunofluorescence (qmIF), spatial analysis and analysis of RNA-based gene signatures to assess for pretreatment TME characteristics associated with pCR to NACT in HER2+/HR+ EBC. Methods: We identified 29 pts with HER2+/HR+ EBC treated with NACT between 2005 and 2015 for which pretreatment biopsy tissue was available. 13 pts (45%) were treated with an anthracycline, 26 (90%) were treated with trastuzumab in addition to chemotherapy and 14 (48%) were treated with trastuzumab and pertuzumab. At surgery, 13 pts (45%) achieved a pCR. A breast cancer pathologist performed TIL analysis according to international guidelines on pretreatment H&E slides. qmIF was performed on 28 pretreatment specimens using an antibody panel targeting CD3, CD8, CD68, FOXP3, and pancytokeratin. We analyzed multispectral images using HALO software to perform tissue segmentation (tumor vs stroma) and phenotypic analysis based on antibody staining patterns. Upon spatially resolving these components, we then performed proximity analysis. We obtained mRNA-based gene signatures via the Nanostring nCounter Breast Cancer 360 Panel for 28 patients. T-tests were performed to evaluate for associations of TME features with pCR. Results: We evaluated the association of pCR with: manual H&E-based TIL assessments, lymphocyte densities and interactions (assessed by spatial proximity) from qmIF, and RNA signatures assessed from the NanoString BC360 panel. Univariate analysis revealed strong associations of inflammation signatures derived from qmIF with pCR, including higher stromal densities of CD3+ (p<0.01), CD8+ (p=0.02) and CD3+CD8-FOXP3- (p=0.02) cells. pCR was also associated with higher ratios of CD3+:CD68+ (p<0.01). This finding remained significant in T-cell subsets CD8+:CD68+ (p=0.04) and was driven by CD3+CD8-FOXP3-:CD68+ (p=0.02). High numbers of lymphocyte interactions, assessed by counting pairs of cells within 30 microns of each other, were also associated with pCR, including CD3+:FOXP3+ (p<0.01) and CD3+CD8-FOXP3-:FOXP3+ (p<0.01). We found no significant associations between pCR and manual H&E based TIL assessments or RNA signatures. Conclusion: In this population of HER2+/HR+ EBC treated with NACT, stromal and intratumoral TIL assessment by standard H&E was not associated with pCR. Higher stromal densities of CD3+, CD8+, and CD3+CD8-FOXP3- TIL subsets were associated with pCR by qmIF and further analysis revealed the presence and proximity of lymphocyte subpopulations correlated with pCR, suggesting that spatial relationships between these populations within the TME contributes to sensitivity to NACT. The lack of association between TILs and pCR in our cohort by standard H&E is likely due to small numbers; however, significance was seen by qmIF, indicating this method as a potentially more sensitive approach to this analysis. Analysis of RNA signatures by NanoString BC360 panel did not reveal signatures associated with pCR . While our study demonstrates the feasibility of this approach to TME evaluation, further studies of larger cohorts are needed to validate markers predictive of response to NACT. Citation Format: Matthew Ryan Kearney, Rami Vanguri, Qi Wang, Kathleen Fenn, Hua Guo, Douglas Marks, Hanina Hibshoosh, Kevin M Kalinsky, Eileen Connolly. Characterization of the tumor microenvironment in patients with hormone receptor positive, HER2 negative early breast cancer [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P2-07-09.

A phase I trial of chemoimmunotherapy combining bacillus Calmette-Guerin (BCG) and intravesical gemcitabine for patients with BCG-relapsing high-grade nonmuscle-invasive bladder cancer.

TPS509 Background: Intravesical BCG is the most effective treatment for high-grade non-muscle invasive bladder cancer (NMIBC), yet recurrences are common. Patients with BCG-relapsing NMIBC are often re-treated with BCG or BCG with interferon (IFN) with an expected response rate of only 40–60%. Several studies show that a major mechanism of resistance to BCG is high levels of myeloid-derived suppressor cells (MDSCs) and regulatory T cells (Tregs) in the pretreatment tumor microenvironment. Gemcitabine is a commonly used intravesical treatment for NMIBC that, in addition to direct anti-tumor cytotoxic effects, may also reduce MDSCs and Tregs. Prior trials combining BCG with intravesical mitomycin C have shown improved efficacy over BCG alone but with higher toxicity. While gemcitabine has been shown to be better tolerated than mitomycin as an intravesical treatment, no study has looked at combined BCG and intravesical gemcitabine. We hypothesize that combining BCG and intravesical gemcitabine will be well tolerated and result in higher response rates by reducing levels of MDSCs and Tregs. A novel aspect of our trial design is the use of a modified continual reassessment method to more accurately identify the maximum tolerated dose instead of the traditional 3 + 3 design used in most NMIBC phase I trials. Methods: This is an investigator-initiated phase I trial (NCT04179162) that will study the safety of alternating intravesical gemcitabine and BCG. Inclusion and exclusion criteria are designed so most patients who would ordinarily be re-treated with BCG or BCG/IFN would be eligible. Patients must have recurrent high-grade NMIBC within 24 months of their last BCG treatment without meeting the criteria for BCG-unresponsive NMIBC. Intravesical gemcitabine is given twice a week on weeks 1, 4, 7, and 10, for a total of 8 doses. BCG (50 mg) is given once a week on weeks 2, 3, 5, 6, 8, and 9, for a total of 6 doses. The trial is monitored using a modified continual reassessment method with increasing dose levels of gemcitabine (500 mg, 1,000 mg, 1,500 mg, and 2,000 mg) being evaluated. Adverse events are assessed using the Common Terminology Criteria for Adverse Events version 5.0. The primary objective is to determine the maximum tolerated dose of this combination to inform our planned phase II trial. Correlative studies will look at the immunomodulating effects of gemcitabine by evaluating changes in immune cell populations in serial blood and urine specimens. Tissue and urine will also be evaluated for molecular determinants of response and resistance to the combination. The trial is open to enrollment with 10 of 25 planned patients accrued to date. Clinical trial information: NCT04179162.

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.

The impact of CTLA-4 blockade and interferon-α on clonality of T-cell repertoire in the tumor microenvironment and peripheral blood of metastatic melanoma patients

ABSTRACTPatients with metastatic melanoma were treated with tremelimumab and interferon-α (IFN) in a previously reported clinical trial [NCT00610857]. Responses were assessed by RECIST criteria as complete (CR) or partial (PR), stable disease (SD) or progressive disease (PD). In this study, T-cell receptor (TCR) beta-chain repertoire was immunosequenced in peripheral blood mononuclear cells (PBMC) specimens (N = 33) and tumor samples (N = 18) utilizing the immunoSEQ® Assay to determine repertoire clonality and T cell fractions at pre-treatment (tumor and PBMC), one month (PBMC) and 3 months (PBMC) time points and evaluate its association with clinical outcomes. In the pretreatment tumor microenvironment (TME), T cell clonality was significantly (p = .035) different and greater in patients who achieved disease control (CR, PR, SD) versus those with non-disease control (PD) as best response to treatment. Further, there was significantly (p = .001) increased TCR fraction in tissue of responders (CR, PR) versus non-responders (PD, SD). In examining T cell clonality in the circulation (PBMC), no significant associations were found in the pretreatment samples. However, early on-treatment (4 weeks) there was a significant decrease in T cell clonality that was associated with improved overall survival (p = .01) and progression-free survival (p = .04). In addition, analysis of temporal changes in tumor-infiltrating lymphocytes (TIL) and peripheral TCR repertoire revealed that responders had significantly higher clonal expansion of TIL in the circulation at 4 weeks than non-responders (p = .036). Our study provided interesting mechanistic data related to CTLA-4 Blockade and IFN and potential biomarkers of immunotherapeutic benefit.

Sensitization to immune checkpoint blockade through activation of a STAT1/NK axis in the tumor microenvironment.

Cancer immunotherapy using antibodies that target immune checkpoints has delivered outstanding results. However, responses only occur in a subset of patients, and it is not fully understood what biological processes determine an effective outcome. This lack of understanding hinders the development of rational combination treatments. We set out to define the pretreatment microenvironment associated with an effective outcome by using the fact that inbred mouse strains bearing monoclonal cancer cell line-derived tumors respond in a dichotomous manner to immune checkpoint blockade (ICB). We compared the cellular composition and gene expression profiles of responsive and nonresponsive tumors from mice before ICB and validated the findings in cohorts of patients with cancer treated with ICB antibodies. We found that responsive tumors were characterized by an inflammatory gene expression signature consistent with up-regulation of signal transducer and activator of transcription 1 (STAT1) and Toll-like receptor 3 (TLR3) signaling and down-regulation of interleukin-10 (IL-10) signaling. In addition, responsive tumors had more infiltrating-activated natural killer (NK) cells, which were necessary for response. Pretreatment of mice with large established tumors using the STAT1-activating cytokine interferon-γ (IFNγ), the TLR3 ligand poly(I:C), and an anti-IL-10 antibody sensitized tumors to ICB by attracting IFNγ-producing NK cells into the tumor, resulting in increased cure rates. Our results identify a pretreatment tumor microenvironment that predicts response to ICB, which can be therapeutically attained. These data suggest a biomarker-driven approach to patient management to establish whether a patient would benefit from treatment with sensitizing therapeutics before ICB.

Clinical Response in ZUMA-1, the Pivotal Study of Axicabtagene Ciloleucel (Axi-Cel) in Patients with Refractory Large B Cell Lymphoma, May Be Influenced by Characteristics of the Pretreatment Tumor Microenvironment (TME)

Clinical Response in ZUMA-1, the Pivotal Study of Axicabtagene Ciloleucel (Axi-Cel) in Patients with Refractory Large B Cell Lymphoma, May Be Influenced by Characteristics of the Pretreatment Tumor Microenvironment (TME)

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

Abstract 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.

Clonality of T-cell repertoire in the tumor microenvironment (TME) and peripheral blood of metastatic melanoma patients treated with CTLA4 blockade and interferon-α (IFN).

9 Background: Patients with metastatic melanoma were treated with tremelimumab and IFN in a previously reported study (Tarhini. J Clin Oncol. 2012). Clonality of T-cell repertoire was analyzed in terms of clinical response both in TME and in peripheral blood. Methods: Patients received tremelimumab 15 mg/kg I.V. every 12 weeks. High dose IFN (HDI) was administered concurrently. Responses were assessed by RECIST as complete (CR) or partial (PR), stable disease (SD) or progression (PD). T-cell receptor beta chain (TCRB) repertoire was immunosequenced in peripheral blood mononuclear cells (PBMC) (N=33 patients) and tumor (N=18) utilizing Adaptive Biotechnologies immunoSEQ platform to determine repertoire clonality and T-cell fractions at pre-treatment (tumor, PBMC), one month (PBMC), and 3 months (PBMC). The clonality metric quantitates, the extent of mono- or oligo-clonal expansion by measuring the shape of the clone frequency distribution. Values range from 0 to 1; values approaching 1 indicate a nearly monoclonal population. Results: In pretreatment TME, T-cell clonality was significantly (p = 0.0008) different and greater in patients who achieved disease control (CR, PR, SD) versus those with PD. Further, there was a significant (p = 0.044) difference between the increased TCR fraction in TME in responders (CR, PR) and non-responders (SD, PD). There was a trend towards association between pretreatment TME T-cell clonality and overall survival (OS) (p = 0.24) and progression free survival (PFS) (p = 0.18) not reaching significance. Within the circulation (PBMC), no significant associations were found by examining the pretreatment samples. However, early on-treatment (day 29) there was significant association and decrease in T-cell clonality and OS (p = 0.005) and PFS (p = 0.003). Conclusions: T-cell clonality in the TME pretreatment is a promising biomarker of immunotherapeutic benefit in our study. While baseline PBMC clonality was not associated with clinical benefit, early on-treatment (day 29) was significantly associated. These findings require validation in an independent cohort and exploration in relation to other immunotherapeutics. Clinical trial information: NCT00610857.

Preamble to the 2015 SITC immunotherapy biomarkers taskforce.

The Society for Immunotherapy of Cancer (SITC) has regularly hosted workshops and working groups focused on immunologic monitoring and immune biomarkers. Due to advances in cancer immunotherapy, including positive results from clinical trials testing new agents and combinations, emerging new technologies for measuring aspects of immunity, and novel candidate biomarkers from early phase trials, the SITC Immune Biomarkers Taskforce has reconvened to review the state of the art, identify current hurdles to further success and to make recommendations to the field. Topics being addressed by individual working groups include: (1) validation of candidate biomarkers, (2) identification of the most promising technologies, (3) testing of high throughput immune signatures and (4) investigation of the pre-treatment tumor microenvironment. Resultant recommendations will be published in JITC.

Unleashing the immune system: PD-1 and PD-Ls in the pre-treatment tumor microenvironment and correlation with response to PD-1/PD-L1 blockade

Focal tumor cell PD-L1 expression adjacent to TIL can be used as a surrogate marker of an ongoing antitumor host response, which may be unleashed by PD-1 blockade. Tumor cell PD-L1 expression is superior to TIL PD-1 expression and the presence of TIL alone, when predicting response to anti-PD-1 therapy.

Highlights of This Issue

The correlation between tumor cell PD-L1 expression in pretreatment surgical pathology specimens and response to anti-PD-1 therapy is an exciting, but preliminary finding. Taube and colleagues expand upon their earlier observations to assess additional histologic and immunoarchitectural features of the pretreatment tumor microenvironment and how they correlate with response to anti-PD1. The presence of immune infiltrates, immune cell subsets, and PD-1, PD-L1 and PD-L2 expression were assessed by immunohistochemistry. Of these, tumor cell PD-L1 expression was the single factor most closely associated with objective response. These findings have both mechanistic and potential biomarker relevance for anti-PD-1 therapy.XAGE1 (GAGED2a) is a cancer/testis (CT) antigen expressed frequently in lung adenocarcinoma, which is the predominant histologic type of lung cancer. Ohue and colleagues investigated the clinical relevance of the XAGE1 (GAGED2a) immune responses in advanced lung adenocarcinoma patients and found that the XAGE1 (GAGED2a) immune response is relevant for better prognosis and that the XAGE1 (GAGED2a) antibody response is a prognostic immune biomarker. On the other hand, XAGE1 (GAGED2a) antigen expression is predictive of a worse prognosis in patients with EGFR-mutated tumors. The protective effect of this naturally occurring immune response supports the concept of immunotherapy.Epstein-Barr virus (EBV) occasionally leads to T- and natural killer-cell lymphoproliferative diseases (T/NK-LPDs) that are refractory to conventional chemotherapies. Kanazawa and colleagues identified that CC chemokine receptor 4 (CCR4) was expressed on most EBV-positive T- and NK-cell lines. A humanized anti-CCR4 monoclonal antibody, mogamulizumab induced antibody-dependent cellular cytotoxicity activity against CCR4-positive cell lines, and inhibited the growth of EBV-positive NK-cell lymphomas in a murine xenograft model. Furthermore, CCR4 was expressed on EBV-infected cells in 8 of 17 patients with EBV-associated T/NK-LPDs. These finding suggests that mogamulizumab may be a promising therapeutic for patients with EBV-associated T/NK-LPDs.STAT3 is activated in many forms of cancer. Because PIAS3 is a key endogenous inhibitor of STAT3, it is possible that PIAS3 expression could be decreased in malignant tissue and thereby contribute to high STAT3 activation. Indeed, Dabir and colleagues demonstrated this was true in malignant mesothelioma as PIAS3 transcript levels were among the lowest of all solid tumors and, conversely, high expression of PIAS3 in mesothelioma tumors is predictive of a favorable prognosis. The authors went on to demonstrate that increasing PIAS3 expression in STAT3-driven mesothelioma cells, either by overexpression of exogenous PIAS3, stimulation of endogenous PIAS3 expression by curcumin or incubation with a PIAS3 peptide mimetic, led to decreased cellular STAT3 activation and promoted apoptosis. These results suggest that strategies to reactivate PIAS3 could represent a new therapeutic avenue to inhibit STAT3 activity and induce growth arrest in tumor cells.