Treatment Of Multiple Tumor Types Research Articles

Boningmycin induces AMPK-mediated endoplasmic reticulum-associated degradation of PD-L1 protein in human cancer cells

Anti-PD-1/PD-L1 monoclonal antibodies have displayed remarkable clinical benefits and revolutionized the treatment of multiple tumor types, but the low response rates and immune-related adverse events limit their application, which promoting the development of small molecule agents to improve the efficacy of PD-1/PD-L1 blockade therapy. Boningmycin (BON), a new small molecule belonging to bleomycin (BLM) family, exhibits potent anticancer activity in vitro and in vivo, as well as negligible lung toxicity, thereby can be an alternative of BLM. However, understandings about the anticancer mechanism of BLM-related compounds are extremely rare, it remains unclear if they affect PD-L1 level in a manner similar to that of other antitumor drugs. In this study, we discover that BON significantly reduces PD-L1 protein level in NCI-H460 and HT-1080 cells. Meanwhile, BON decreases the protein level of PD-L1 in a tumor xenograft model of NCI-H460 cells. Nevertheless, the mRNA level is not influenced after BON exposure. Furthermore, BON-induced PD-L1 reduction is proteasome- dependent. By using specific inhibitors and RNA interference technology, we confirm that the decline of PD-L1 protein by BON is mediated by AMPK-activated endoplasmic reticulum-associated degradation pathway, which is like to the action of metformin. Last but not the least, BON has synergism on gefitinib in vitro and in vivo. In conclusion, it is the first report demonstrating that BON decreases PD-L1 protein level through AMPK-mediated endoplasmic reticulum-associated degradation pathway. These findings will benefit the clinical transformation of BON and aid in the elucidation of molecular mechanism of BLM-related compounds.

Predictive biomarkers of immunotherapy response with pharmacological applications in solid tumors.

Immune-checkpoint inhibitors show promising effects in the treatment of multiple tumor types. Biomarkers are biological indicators used to select patients for a systemic anticancer treatment, but there are only a few clinically useful biomarkers such as PD-L1 expression and tumor mutational burden, which can be used to predict immunotherapy response. In this study, we established a database consisting of both gene expression and clinical data to identify biomarkers of response to anti-PD-1, anti-PD-L1, and anti-CTLA-4 immunotherapies. A GEO screening was executed to identify datasets with simultaneously available clinical response and transcriptomic data regardless of cancer type. The screening was restricted to the studies involving administration of anti-PD-1 (nivolumab, pembrolizumab), anti-PD-L1 (atezolizumab, durvalumab) or anti-CTLA-4 (ipilimumab) agents. Receiver operating characteristic (ROC) analysis and Mann-Whitney test were executed across all genes to identify features related to therapy response. The database consisted of 1434 tumor tissue samples from 19 datasets with esophageal, gastric, head and neck, lung, and urothelial cancers, plus melanoma. The strongest druggable gene candidates linked to anti-PD-1 resistance were SPIN1 (AUC = 0.682, P = 9.1E-12), SRC (AUC = 0.667, P = 5.9E-10), SETD7 (AUC = 0.663, P = 1.0E-09), FGFR3 (AUC = 0.657, P = 3.7E-09), YAP1 (AUC = 0.655, P = 6.0E-09), TEAD3 (AUC = 0.649, P = 4.1E-08) and BCL2 (AUC = 0.634, P = 9.7E-08). In the anti-CTLA-4 treatment cohort, BLCAP (AUC = 0.735, P = 2.1E-06) was the most promising gene candidate. No therapeutically relevant target was found to be predictive in the anti-PD-L1 cohort. In the anti-PD-1 group, we were able to confirm the significant correlation with survival for the mismatch-repair genes MLH1 and MSH6. A web platform for further analysis and validation of new biomarker candidates was set up and available at https://www.rocplot.com/immune . In summary, a database and a web platform were established to investigate biomarkers of immunotherapy response in a large cohort of solid tumor samples. Our results could help to identify new patient cohorts eligible for immunotherapy.

Abstract PR010: Development of a pre-clinical metastatic model of human sarcoma to identify therapeutic targets

Abstract Targeted therapies have led to significant advances in the treatment of multiple tumor types resulting in more effective and often, less toxic therapeutic options. In sarcomas, the development of targeted therapies has been met limited success. There are more than 70 sarcoma subtypes that vary in histology, clinical course and patient demographics. Despite these clear differences, clinically, sarcomas are treated similarly with variable efficacy. Patients with localized disease are treated with surgery, radiation, and often chemotherapy. Even with this aggressive multimodality treatment, 35% of patients will develop incurable metastatic disease. This highlights the need for additional therapies targeting micrometastatic disease or cells within the primary tumor with a high propensity for metastasis. Understanding the pathways driving the formation of sarcoma metastasis would allow for the development of new therapies. Targeted treatments are limited due to the heterogeneity of the disease and the paucity of pre-clinical models that accurately reflect the human disease. We have focused on creating in vivo models of sarcoma development and metastasis that can be used as the basis of further studies and to test potential therapeutic targets. Mesenchymal stem cells (MSCs) are the presumed cell of origin for sarcomas and therefore, the starting cell for our investigations. We hypothesized that by recreating key genetic events in human MSCs, we could generate sarcomas in vivo that are reflective of the human disease. RB1 and P53, tumor suppressors that are often mutated or functionally inactive in sarcomas were first targeted using CRISPR-Cas9 technology in MSCs that have been immortalized by human telomerase (hTERT). Genes that are overexpressed or amplified in The Cancer Genome Atlas (TCGA) data were identified and a library of potential oncogenes was generated. This library was then added to RB1-/-P53+/- cells through lentiviral transduction. Targeting of key tumor suppressors and adding oncogenic drivers resulted in the formation of high-grade human sarcomas subcutaneously. We then sought to investigate the ability of these cells to metastasize. Injection of cells intramuscularly (into the thigh) in immunocompromised mice resulted in the formation of spontaneous lung metastasis without clear evidence of disease in other organs. This pattern clinically reflects that of human disease. Comparing oncogenic genes from metastatic outgrowths to primary tumors identified KLF4, DDIT3, JUN, and KRAS as being enriched in metastatic cells. This system allows for reproducible and robust genetic manipulation of tumor cells to characterize key drivers of metastatic growth. This will result in the identification and validation of new therapeutic targets to treat or prevent metastatic disease in our patients. Citation Format: Janai R. Carr-Ascher. Development of a pre-clinical metastatic model of human sarcoma to identify therapeutic targets [abstract]. In: Proceedings of the AACR Special Conference: Sarcomas; 2022 May 9-12; Montreal, QC, Canada. Philadelphia (PA): AACR; Clin Cancer Res 2022;28(18_Suppl):Abstract nr PR010.

Deletions on 9p21 are associated with worse outcomes after anti-PD-1/PD-L1 monotherapy but not chemoimmunotherapy

NCCN guidelines for first-line treatment of advanced non-squamous non-small-cell lung cancer (NSCLC) patients without targetable driver alterations includes either immunotherapy alone or in combination with chemotherapy. In this study, we investigated genomic predictors of survival after immunotherapy to guide this treatment decision. Cox proportional hazards regression was used to identify genomic correlates of survival in a cohort of EGFR/ALK-, non-squamous NSCLC patients treated with first-line pembrolizumab monotherapy (mono-IO) or pembrolizumab in combination with carboplatin/cisplatin and pemetrexed (chemo-IO) within a real-world clinico-genomic database. The effect of deletions on 9p21 was further evaluated in five additional tumor types. Among mono-IO treated non-squamous NSCLC patients, tumors with 9p21.3 gene deletions (CDKN2A, CDKN2B, MTAP) were associated with worse survival compared to the corresponding deletion-negative tumors (CDKN2A deletion HR = 1.8, P = 0.001). However, this association was not observed among chemo-IO treated patients (CDKN2A deletion HR = 1.1, P = 0.4). This finding remained after adjusting for clinical and genomic features including TMB and PD-L1. Deletions at 9p21.3 were not associated with differences in TMB, PD-L1, or tumor inflammation. Due to the high incidence of 9p21.3 deletions across tumor types, we performed a pan-cancer analysis and found CDKN2A deletion-positive tumors had worse survival following first-line immunotherapy treatment in multiple tumor types (HR = 1.4, P < 0.001). These results indicate deletions at 9p21.3 are a putative negative predictor of clinical benefit from first-line immune checkpoint inhibitors and may have utility in choosing between mono-IO vs chemo-IO regimens in NSCLC.

Abstract LB534: Development of GB2101, a novel anti-CCR8 antibody for cancer treatment

Abstract Background: Regulatory T cells (Tregs) play a crucial role in suppressing immune response and maintaining hemostasis and immune tolerance. Tregs are enriched in the tumor microenvironment (TME) and suppress anti-tumor immunity. Therefore, specific depletion of Tregs in the TME is expected to reduce anti-tumor immune suppression without affecting hemostasis in the periphery. The C-C motif chemokine receptor 8 (CCR8), highly expressed on Tregs from TME but significantly lower expressed on Tregs from peripheral blood, provides an ideal target for preferentially deletion of Tregs within tumors. GB2101 is a novel anti-CCR8 monoclonal antibody generated from hybridoma. The data from in vitro and in vivo studies indicated that GB2101 is a good PCC molecule with great potential for clinical development. Methods: GB2101 was generated by immunization of CCR8 gene plus CCR8 over-expressing cells in mice followed by hybridoma technology. The binding of the antibody to CCR8-expressing cells was detected by flow cytometry. CCL1 ligand blocking was assessed by flow cytometry and calcium flux assay. Antibody-dependent cell-mediated cytotoxicity (ADCC) function was evaluated by Jurkat-CD16A-NFAT reporter system. In vivo anti-tumor efficacy was assessed in syngeneic model using human CCR8 knock-in mice. Results: GB2101 displayed potent binding to cells expressing CCR8. GB2101 efficiently blocked CCL1 binding and CCL1-induced signals in CCR8 expressing cells. ADCC activity against target cells was observed and afucosylated version of GB2101 improved ADCC response. GB2101 significantly inhibited tumor growth in syngeneic model. Conclusions: GB2101 is a novel monoclonal antibody specifically binding to CCR8 with high affinity, and efficiently blocked CCL1-CCR8 pathway and suppressed tumor growth in vivo. Therefore, it is a very promising preclinical candidate that may be used in the treatment of multiple tumor types. Citation Format: Qinglin Du, Yiqi Cao, Xueyan Yang, Jing Lu, Fei Peng, Wenming Zhou, Liwen Liang, James Li, Shuhua Han. Development of GB2101, a novel anti-CCR8 antibody for cancer treatment [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 LB534.

Abstract 1399: Discovery and development of PARP inhibitor senaparib

Abstract Poly (ADP-ribose) polymerase (PARP) is a key enzyme for DNA repair. PARP inhibitors have been shown to be effective against cancers with DNA repair defects, such as with BRCA1 or BRCA2 mutations. Several PARP inhibitors, including olaparib, rucaparib, niraparib, talazoparib, fluzoparib and pamiparib have been approved for the treatment of several types of cancer. In this presentation, we will report our discovery and development of senaparib (IMP4297) as a potent PARP inhibitor. We will present studies led to the identification of senaparib as a clinical candidate, as well as IND enabling in vitro and in vivo characterization of senaparib. Preclinical data indicated that senaparib had a wide therapeutic window (single agent effective dose of 2.5-21 mg/kg QD, in a BRCA1 mutated MDA-MB-436 human breast cancer xenograft model), which was confirmed in clinical studies (effective dose of 20-120 mg QD, and no DLT was found up to 150 mg QD). Senaparib is currently in several phase I/II, phase II and phase III clinical studies for the treatment of multiple tumor types either as single agent or in combination with temozolomide (TMZ). The most advanced study of senaparib is a phase III study as maintenance therapy in platinum-sensitive advanced ovarian cancer patients following first-line chemotherapy (ClinicalTrials.gov Identifier: NCT04169997). Citation Format: Sui Xiong Cai, Ning Ma, Xiaozhu Wang, Yangzhen Jiang, Mingchuan Guo, Chih-Yi Hsieh, Ye Edward Tian. Discovery and development of PARP inhibitor senaparib [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 1399.

Landscape of Immunotherapy in Genitourinary Malignancies.

The past decade has witnessed a revolution in the development of immune checkpoint inhibitors for the treatment of multiple tumor types, including genitourinary cancers. Immune checkpoint inhibitors have notably improved the treatment outcomes of patients with metastatic renal cell carcinoma and metastatic urothelial carcinoma. In prostate cancer, the role of immunotherapy with checkpoint inhibitors is not yet established except for microsatellite instability high (MSI-H) tumors. Other immunotherapeutic approaches that have been explored in these malignancies include cytokines, vaccines, and cellular therapy. Ongoing studies are exploring the use of immunotherapy combinations as well as combination with chemotherapy and targeted therapy in these types of tumors. The use of immunotherapy beyond the metastatic setting is an active area of research. Moreover, there is great interest in biomarker development to predict response to immunotherapy and risk of toxicity. This book chapter is a comprehensive review of immunotherapeutic approaches, both approved and investigational, for the treatment of renal cell carcinoma, urothelial carcinoma, and prostate cancer.

A pan-cancer analysis of HER2 index revealed transcriptional pattern for precise selection of HER2-targeted therapy.

BackgroundThe prevalence of HER2 alterations in pan-cancer indicates a broader range of application of HER2-targeted therapies; however, biomarkers for such therapies are still insufficient and limited to breast cancer and gastric cancer.MethodsUsing multi-omics data from The Cancer Genome Atlas (TCGA), the landscape of HER2 alterations was exhibited across 33 tumor types. A HER2 index was constructed using one-class logistic regression (OCLR). With the predictive value validated in GEO cohorts and pan-cancer cell lines, the index was then applied to evaluate the HER2-enriched expression pattern across TCGA pan-cancer types.FindingsIncreased HER2 somatic copy number alterations (SCNAs) could be divided into two patterns, focal- or arm-level. The expression-based HER2 index successfully distinguished the HER2-enriched subtype from the others and provided a stable and superior performance in predicting the response to HER2-targeted therapies both in breast tumor tissue and pan-cancer cell lines. With frequencies varying from 12.0% to 0.9%, tumors including head and neck squamous tumors, gastrointestinal tumors, bladder cancer, lung cancer and uterine tumors exhibited high HER2 indices together with HER2 amplification or overexpression, which may be more suitable for HER2-targeted therapies. The BLCA.3 and HNSC.Basal were the most distinguishable subtypes within bladder cancer and head and neck cancer respectively by HER2 index, implying their potential benefits from HER2-targeted therapies.InterpretationAs a pan-cancer predictive biomarker of HER2-targeted therapies, the HER2 index could help identify potential candidates for such treatment in multiple tumor types by combining with HER2 multi-omics features. The discoveries of our study highlight the importance of incorporating transcriptional pattern into the assessment of HER2 status for better patient selection.FundingThe National Key Research and Development Program of China; Clinical Research and Cultivation Project of Shanghai ShenKang Hospital Development Center.

Immunomodulatory Activities of the Heparan Sulfate Mimetic PG545.

Heparanase regulates multiple biological activities that enhance tumor growth and metastatic spread. Heparanase cleaves and degrades heparan sulfate (HS), a key structural component of the extracellular matrix that serves as a barrier to cell invasion and also as a reservoir for cytokines and growth factors critical for tumor growth and metastasis. For this reason, heparanase is an attractive target for the development of novel anti-cancer therapies. Pixatimod (PG545), a heparanase inhibitor, has shown promising results in the treatment of multiple tumor types. PG545 offers a diversity of mechanisms of action in tumor therapy that include angiogenic inhibition, inhibition of growth factor release, inhibition of tumor cell migration, tumorcell apoptosis, activation of ER stress response, dysregulation of autophagy, and NK cell activation. Further investigation into the role that heparanase and its inhibitors play in tumor therapy can lead to the development of effective tumor therapies.

Current Landscape of Immunotherapy in Genitourinary Malignancies.

The past decade has witnessed a revolution of immune checkpoint inhibitors in the treatment of multiple tumor types, including genitourinary cancers. Immune checkpoint inhibitors improved the treatment outcomes of patients with metastatic renal cell carcinoma and metastatic urothelial carcinoma. In prostate cancer, the role of immunotherapy with checkpoint inhibitors is not yet established, but clinical trials investigating their use are ongoing. Other immunotherapeutic approaches that have been explored in these malignancies include cytokines, vaccines, and cellular therapy. Ongoing studies are exploring the use of immunotherapy combinations as well as combination with chemotherapy and targeted therapy in these types of tumors. The use of immunotherapy beyond the metastatic setting is an active area of research. Moreover, there is a great interest in biomarker development to predict response to immunotherapy and risk of toxicity. This chapter is a comprehensive review of the immunotherapeutic approaches, both approved and investigational, for the treatment of renal cell carcinoma, urothelial carcinoma, and prostate cancer.

Interaction of novel Aurora kinase inhibitor MK-0457 with human serum albumin: Insights into the dynamic behavior, binding mechanism, conformation and esterase activity of human serum albumin

MK-0457, a new pan-aurora kinase inhibitor, is in Phase II clinical development for the treatment of multiple tumor types and hematologic malignancies. The present work explored the dynamic behaviors and interaction mechanism of MK-0457 to human serum albumin (HSA) and the effect on the esterase-like activity and conformation of HSA by computer simulations and experiments. Docking and molecular dynamics trajectory analysis indicated that MK-0457 stably bound to Sudlow’s site 2 of HSA by multiple types of interaction forces. Competitive experiments further verified MK-0457 was bound at first to Sudlow’s site 2 and then the excess of drug was bound to Sudlow’s site 1. The steady-state fluorescence combined with ultraviolet–visible absorption and fluorescence lifetime measurements specified a static quenching mechanism with association constants of 104 M−1 reflecting moderate binding affinity of MK-0457 for HSA. The analysis of Rg values showed that the structure of HSA became loose due to MK-0457 binding, inducing slight conformational changes of HSA, which was consistent with the results obtained from circular dichroism, synchronous, and 3D fluorescence spectroscopy. The esterase-like activity of HSA showed that MK-0457 inhibits the catalytic activity of subdomain IIIA of HSA by binding to the vital residues TYR411. Atomic force microscopy images indicated that MK-0457 affects the molecular sizes of HSA by transforming the morphology of HSA from aggregation diploids to small monomers. This study is beneficial for understanding the biological action of MK-0457, providing additional information about the feasibility of its transport and accumulation in blood plasma.

Abstract 4062: Activation of innate and adaptive immunity using intratumoral tilsotolimod (IMO-2125) as monotherapy in patients with refractory solid tumors: a phase Ib study (ILLUMINATE-101)

Abstract While checkpoint inhibitor therapy has transformed treatment of multiple tumor types, many patients remain refractory. Tilsotolimod, a toll-like receptor 9 agonist, has been shown in preclinical models to activate plasmacytoid dendritic cells and increase T cell infiltration to the tumor microenvironment. Preliminary results of a phase 1/2 study suggested that intratumoral injection of tilsotolimod in combination with ipilimumab may revive an immune response in patients with immune checkpoint inhibitor-resistant metastatic melanoma. To further explore the role of tilsotolimod in modulating the tumor immune microenvironment, we conducted a Phase Ib monotherapy trial (ILLUMINATE-101). Adults with histologically or cytologically confirmed diagnosis of cancer not amenable to curative therapies received intratumoral tilsotolimod in doses escalating from 8 mg to 32 mg into a single lesion at weeks 1, 2, 3, 5, 8, and 11. Objectives of the dose evaluation portion included characterizing safety and pharmacokinetics, and evaluating alterations in the tumor microenvironment. Blood samples and tumor biopsies of injected and distal lesions were obtained at baseline and on treatment. Immune analyses included evaluation using Nanostring and/or flow cytometry of activation of the type 1 interferon (IFN) pathway, IFN gamma levels, activation of dendritic cell subsets, and changes in T cell status. As of November 7, 2018, 41 patients have been enrolled, including 38 patients into the dose evaluation portion and 3 patients into a melanoma expansion cohort. No dose-limiting toxicities or treatment-related adverse events have been observed. Within 24 hours, fresh tumor biopsies showed significant increases in IFN gamma levels, activation of the type 1 IFN pathway, induction of an antigen processing gene signature (a measure of the MHC class I antigen presentation pathway), and maturation of dendritic cells as measured by expression of HLA-DR (MHC class II), compared to pretreatment biopsies. Of 25 evaluable patients who received at least 1 dose of tilsotolimod and had at least 1 post-baseline disease assessment, 12 (48%) had a RECIST v1.1 disease assessment of stable disease. For patients with at least one disease assessment following documentation of stable disease (n=8), duration of stable disease ranged from 0.53 to 4.2+ months, with 3 patients ongoing. These results demonstrate that single agent tilsotolimod was well tolerated and induced robust alterations in the tumor microenvironment. Citation Format: Hani M. Babiker, Vivek Subbiah, Orla Maguire, Shah Rahimian, Hans Minderman, Cara L. Haymaker, Chantale Bernatchez, Erkut Borazanci, James Geib, Srinivas K. Chunduru, Peter M. Anderson, Igor Puzanov, Adi Diab. Activation of innate and adaptive immunity using intratumoral tilsotolimod (IMO-2125) as monotherapy in patients with refractory solid tumors: a phase Ib study (ILLUMINATE-101) [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 4062.

Abstract 693: Deep learning analysis of circulating tumor DNA identified a pan-tumor molecular subtype with enhanced response to durvalumab (anti-PDL1)

Abstract Tumor mutation burden (TMB) has emerged as a promising predictive biomarker for anti-PD1/L1; however, whether somatic mutations in specific genes can sensitize to immunotherapy is poorly understood. We used deep learning to identify molecular subtypes from mutations detectable in circulating tumor DNA (ctDNA) and associated these with outcomes with anti-PDL1 (durvalumab) and durvalumab + anti-CTLA4 (tremelimumab) therapy. Patient blood samples from 4 nonrandomized phase 2 trials evaluating durvalumab (NCT01693562, 1L+ solid tumors; NCT02087423, 3L+ NSCLC) or durvalumab+ tremelimumab (NCT02000947, 2L+ NSCLC; NCT02261220, 2L+ solid tumors) were sequenced with the Guardant 360 assay of 73 genes. CtDNA mutations were examined pre-treatment in a discovery cohort of 818 patients composed of &amp;gt;15 tumor types and validated in a cohort of 94 patients composed of &amp;gt;5 tumor types. Deep learning neuron network was computed using Tensorflow to identify 4 unique molecular subgroups. Kaplan-Meier analysis was calculated and objective response rates (ORR) were assessed with RECISIST v1.1. The subgroups consisted of: DS1 (N = 215/818, 26%) enriched in RB1 mutations (17%) and low TMB, DS2 (N = 237/818, 29%) enriched in ARID1A (33%), NFE2L2 (8%), and cKIT (13%) mutations, DS3 (N = 251/818, 31%) enriched in EGFR, ERBB2, BRAF and STK11 mutations, and DS4 (N = 115/818, 14%) enriched in TERT, FGFR3, and PIK3CA mutations. In the discovery cohort, the DS2 subgroup had most improved outcomes (mOS=24.6 months, mPFS=3.7 months, ORR=27%) compared to the other 3 subgroups. DS1 subgroup had the worst outcomes (mOS=6.3 months, mPFS=1.6 months, ORR=10%), while the biomarker evaluable population (BEP, n=818) had ORR=17%. In the validation cohort, DS2 also had the most improved outcomes (mOS=not reached, mPFS=13.2 months, and ORR=64%), with the BEP (n=94) having an ORR=37%. PD-L1 was not correlated with any specific molecular subgroup, while an IFNg mRNA signature trended with correlation with subgroup DS2. Deep learning analysis of ctDNA identified a molecular subgroup with enhanced response to anti-PDL1 treatment in multiple tumor types. Citation Format: Song Wu, Sriram Sridhar, Han Si, Michael Kuziora, Judson Englert, Shaad E. Abdullah, Philip Dennis, Feng Xiao, Guozhi Gao, Koustubh Ranade, Brandon W. Higgs. Deep learning analysis of circulating tumor DNA identified a pan-tumor molecular subtype with enhanced response to durvalumab (anti-PDL1) [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 693.

Adverse events following the use of immune checkpoint inhibitors: An analysis of the WHO VigiAccess database.

e13118 Background: Immune checkpoint inhibitors (ICIs), especially ipilimumab (ipi) and nivolumab (nivo), have received approvals from the U.S. Food and Drug Administration for the treatment of multiple tumor types. These medications have shown great promise in the treatment of several malignancies but are associated with immune-related adverse events. This study was undertaken to better understand the patterns of adverse events following different ICIs. Methods: We used the World Health Organization (WHO) Vigiaccess Database, the largest adverse events reporting database, to identify, summarize, and report adverse drug events (AE) attributed to ipi and nivo. The database contains reports for ipi beginning in 2008 and for nivo beginning in 2012. We manually extracted the data from the database and conducted Chi-square tests to examine the difference in occurrence of AEs in various organ systems between patients receiving ipi and nivo. The five most common organ systems affected by AE associated with ipi and nivo were identified. Results: AEs were reported in 15,504 ipi users and 21,306 nivo users. Ipi users reported significantly higher AEs in gastrointestinal system compared to nivo users (p &lt; 0.0001). Conversely, nivo users reported significantly higher AEs in respiratory disorders (p &lt; 0.0001), skin and subcutaneous tissue organ systems (p = 0.0001), and neoplasms benign, malignant and unspecified (p &lt; 0.0001) compared to ipi users. Conclusions: To our knowledge this is the largest study on reported AEs following ipi and nivo. The patterns of treatment-related AEs differed significantly for these two immune checkpoint inhibitor therapies. Further studies are required to guide treatment selection.[Table: see text]

An immunosuppressive macrophage profile attenuates the prognostic impact of CD20-positive B cells in human soft tissue sarcoma

BackgroundImmune cells can regulate disease progression and response to treatment in multiple tumor types, but their activities in human soft tissue sarcoma are poorly characterized.MethodsMarker-defined immune cell subsets were characterized from a tumor microenvironmental perspective in two independent cohorts of human soft tissue sarcoma by multiplex IHC, quantitative PCR and/or bioinformatics.ResultsB cell profiling revealed a prognostic role for CD20 protein (cohort 1, 33 patients) and MS4A1 gene expression (cohort 2, 265 patients). Multiplex IHC and gene correlation analysis supported a role in antigen presentation, immune cell differentiation and T cell activation. The prognostic role of MS4A1 expressing B cells was only observed in an IL10low, PTGS2low or CD163low tumor microenvironment according to the transcriptomic data. IL10 levels consistently correlated with the M2-like macrophage marker CD163, which also defined the majority of macrophages. A polarization of these cells toward a pro-tumoral phenotype was further supported by lack of correlation between CD163 and M1 markers like NOS2, as well as by low abundance of CD80 positive cells in tissue.ConclusionsAnalysis of CD20/MS4A1 expression in soft tissue sarcoma merits further attention as a promising candidate prognostic tool for survival, but not in patients with a pronounced immunosuppressive tumor microenvironment. Macrophages are ubiquitous and polarized toward a protumoral phenotype. This provides a rationale for further studies on B cell function and immunotherapy targeting M2-polarized macrophages.

Nivolumab in the treatment of microsatellite instability high metastatic colorectal cancer.

Nivolumab is a PD-1 inhibitor approved for the use in treatment of multiple tumor types (such as melanoma, non-small-cell lung cancer, renal cell carcinoma, urothelial cancer and Hodgkin's lymphoma). In July 2017, the US FDA granted accelerated approval of this agent for the treatment of metastatic colorectal cancer patients whose tumor harbors deficient mismatch repair, or microsatellite-instability high and have progressed on conventional chemotherapy. In this review, we will discuss the use, efficacy, and safety of this agent in microsatellite-instability high metastatic colorectal cancer.

RNAScope as a platform to detect IDO1 expression in tumor tissue sections.

116 RNAScope is a sensitive, specific platform to detect IDO1 expression in tumor tissue sections. M Pratta, M Rupar, P Waeltz, T Burn, G Hollis, M Covington, M Smith, and R Newton. Incyte Corp. Wilm. DE. Background: Indoleamine 2,3-Dioxygenase 1 (IDO1) catalyzes the primary and rate-limiting step in tryptophan catabolism to generate N-formyl-kynurenine (Kyn). Through a combination of local depletion of tryptophan and an increase in Kyn concentrations, IDO-1 activity can result in the suppression of antitumor immune responses. Because IDO-1 inhibitors are now in the clinic for treatment of multiple tumor types, immunohistological approaches are employed to demonstrate IDO1 expression in tumor biopsies. However, using a commercially available antibody to detect IDO1 by immunohistochemistry (IHC), the level of sensitivity was inadequate. Methods: In order to improve the sensitivity of IDO1 detection, we evaluated in situ hybridization (ISH) using RNAScope technology and digital quantitation by HALO analysis in collaboration with Advanced Cell Diagnostics (ACD). The technology was cross-validated using IDO1 qRT-PCR, Western blot, and activity analysis and compared with standard IHC. We initially evaluated IDO1 expression in HeLa cells stimulated with various concentrations of IFNγ, and then extended the observations using tissue sections from multiple tumor types. Results: In the HeLa cell model, IFNγ induced a time- and concentration-dependent increase of IDO1 at the mRNA, protein, and activity level. Although IDO1 was successfully detected in the HeLa cell samples by IHC, comparison of the platforms indicated IFNγ EC50 values were in strong agreement between RNAScope (193.8 pg/ml) and Western blot analysis (170.8 pg/ml), but was much higher by IHC analysis (2206 pg/ml). A strong positive correlation (*p &lt; 0.0001) between RNAScope and Western blot analysis was observed, suggesting a highly coordinated induction of IDO1 by IFNγ at both the mRNA and protein levels. FFPE tumor tissue from melanoma, HNSCC, bladder, renal, ovarian, and lung cancers visualized by RNAScope all show varying levels of IDO1 expression. Conclusions: These data support the use of RNAScope for the analysis of IDO1 expression in clinical trials.

Clinical characteristics of patient selection and imaging predictors of outcome in solid tumors treated with checkpoint-inhibitors.

The rapidly evolving knowledge on tumor immunology and the continuous implementation of immunotherapy in cancer have recently led to the FDA and EMA approval of several checkpoint inhibitors as immunotherapic agents in clinical practice. Anti-CTLA-4, anti-PD-1, and anti-PDL-1 antibodies are becoming standard of care in advanced melanoma, as well as in relapsed or metastatic lung and kidney cancer, demonstrating higher and longer response compared to standard chemotherapy. These encouraging results have fostered the evaluation of these antibodies either alone or in combination with other therapies in several dozen clinical trials for the treatment of multiple tumor types. However, not all patients respond to immune checkpoint inhibitors, hence, specific biomarkers are necessary to guide and monitor therapy. The utility of PD-L1 expression as a biomarker has varied in different clinical trials, but, to date, no consensus has been reached on whether PD-L1 expression is an ideal marker for response and patient selection; approximately 20-25% of patients will respond to immunotherapy with checkpoint inhibitors despite a negative PD-L1 staining. On the other hand, major issues concern the evaluation of objective response in patients treated with immunotherapy. Pure morphological criteria as commonly used in solid tumors (i.e. RECIST) are not sufficient because change in size is not an early and reliable marker of tumor response to biological therapies. Thus, the scientific community has required a continuous adaptation of immune-related response criteria (irRC) to overcome the problem. In this context, metabolic information and antibody-based imaging with positron emission tomography (PET) have been investigated, providing a powerful approach for an optimal stratification of patients at staging and during the evaluation of the response to therapy. In the present review we provide an overview on the clinical characteristics of patient selection when using imaging predictors of outcome in solid tumors treated with checkpoint-inhibitors.

Intratumoral Administration of the Immunotherapeutic Combination Anti-ctla4, Anti-cd137 and Anti-ox40: Comparison to Systemic Administration, Peri-Draining Lymph Node Injection, and Cellular Vaccine in a Mouse Lymphoma Model

Immunotherapy has come of age and is truly a breakthrough in the treatment of cancer. Immune checkpoint inhibition is now an established and effective modality for treatment of multiple tumor types. Combination immunotherapy creates even more potential for efficacy by targeting synergistic immune pathways. However, systemically administered immunomodulators can activate T-cells non-specifically resulting in off-target toxicity, which is dose-limiting and potentially lethal in combination. Intratumoral administration of immunotherapeutic agents has several advantages including 1) higher concentrations of agents in close proximity to target antigens and tumor-infiltrating lymphocytes 2) lower doses overall with less systemic exposure and toxicity 3) potentially a novel mechanism of action such as depletion of intratumoral Tregs 4) potential for an abscopal effect, acting as an in-situ cancer vaccine.Here we report a novel combination of immunomodulators, anti-CTLA4, CD137 and OX40 administered by intratumoral route in a mouse lymphoma model (A20) as well as a colon cancer model (MC38). CTLA4 is an immune checkpoint, and CD137 and OX40 are members of the TNF receptor superfamily - all agents in clinical practice or clinical trials.For both the A20 and MC38 cell lines, a dual tumor model was used in which tumor cells were inoculated bilaterally on the flanks. BALBC mice were used for the A20 model and C57BL/6 mice for MC38. Treatment was started approximately day 8 when there were visible tumors between 5-7mm in diameter. Intratumoral injection was to the left tumor only.Injection of the triple combination at doses about 1/10 that of usual systemic doses (30 ug each) resulted in significant tumor growth inhibition/regression and a significant survival advantage for both the A20 and MC38 models. For the A20 model, at doses of approximately 1/40 systemic doses (10ug each) the triple combination resulted in tumor clearance in 70-100% of mice, and significantly prolonged survival. There was no toxicity observed. The majority of the mice remained tumor free, and did not grow tumor when rechallenged with A20 cells. The response was shown to be CD8 T-cell dependent, and in vivo CD8 depletion, but not CD4 depletion led to complete abrogation of the treatment effect. A memory t-cell response was confirmed in vitro, with CD8CD44(hi) T-Cells demonstrating increased IFN-g production when incubated with A20 cells, but not control cells (4T1 breast ca). Intratumoral administration at low doses was more effective than 2 systemic routes - intraperitoneal (IP) and subcutaneous (SC), supporting a local in situ vaccine effect. Interestingly, in single tumor model, SC injection in proximity to the tumor draining lymph node (DLN) was significantly more effective than SC injection close to a non-tumor DLN, suggesting that the tumor DLN may be equally involved as the tumor microenvironment in establishing an in situ vaccine effect. Finally, in a single tumor model, a cell based vaccine of irradiated A20 cells co-injected subcutaneously with the low dose triple combination at a site distant from the tumor and tumor DLN had anti-tumor effects greater than the triplet alone SC at the same location, but less than IT or when injected SC in proximity to the tumor DLN.Thus we demonstrate that this novel combination of immunomodulators delivered intratumorally induces a dramatic anti-tumor effect. At low doses, the triple combination is more effective when delivered IT than by systemic routes and the anti-tumor immune response is completely dependent on CD8 T-cells, supporting an in situ vaccine effect. Importantly, it appears both the tumor microenvironment and DLN are important to the anti-tumor immune response. Injecting in the region of the tumor DLN may be a viable and effective option clinically when an injectable tumor site is not easily accessible. The A20 cellular vaccine delivered together with the low dose triple combo at a site distant from the tumor was more effective than triple combo alone, but less effective than intratumoral, suggesting that elements of the tumor microenvironment and/or tumor DLN are important for full effect.Overall these results demonstrate potent anti-tumor effects of the triple combination anti-CTLA4, -CD137 and -OX40, all agents in clinical practice or clinical trials, and support the intratumoral route as safe and highly efficacious route of administration. DisclosuresHebb:Alligator Biosciences: Research Funding. Ellmark:Alligator Biosciences: Employment. Norlen:Alligator Biosciences: Employment. Felsher:Alligator Biosciences: Research Funding.

Abstract B009: Design and development of HDAC6-selective inhibitors for hematological cancer treatment and solid tumor immunotherapy

Abstract Despite its name, HDAC6 is primarily a tubulin deacetylase, not a histone deacetylase, and it has emerged as a particularly interesting – and unique – cancer target as it plays an essential role in stress response and in aggresomal protein degradation: specifically, HDAC6 binds polyubiquitinated misfolded proteins and recruits misfolded protein cargo to dynein motors for transport to aggresomes. Cells deficient in HDAC6 fail to clear these misfolded protein aggregates from the cytoplasm, cannot form aggresomes properly, and are hypersensitive to the accumulation of misfolded proteins, which leads to activation of apoptosis. Further, recent evidence has emerged of HDAC6 modulating immune-related pathways in solid tumors, notably regulating PD-L1 expression through STAT3 modulation. In order to explore the clinical potential of HDAC6 in both hematological and solid tumor immunotherapy, we have de novo-designed a class of highly-potent, ultra-selective and orally-active HDAC6 inhibitors with potential in the treatment of multiple tumor types, including through immunotherapeutic mechanisms. Additionally, owing to the selectivity we have achieved for HDAC6 with our lead compounds, much greater opportunities for broader combination modalities can be realized, and we have established potentiation of our leads with other tumor immunotherapeutics in in vivo syngeneic models. The profile of our preclinical development candidate will be presented. Citation Format: Stephen J. Shuttleworth. Design and development of HDAC6-selective inhibitors for hematological cancer treatment and solid tumor immunotherapy. [abstract]. In: Proceedings of the CRI-CIMT-EATI-AACR Inaugural International Cancer Immunotherapy Conference: Translating Science into Survival; September 16-19, 2015; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(1 Suppl):Abstract nr B009.