bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 4089: Antitumor activity of eribulin in combination with anti-PD1 antibody in a mouse syngeneic breast cancer model
Authors: Semba Taro , Tabata Kimiyo , Ozawa Yoichi , Miyano Saori Watanabe , Matsui Junji , Funahashi Yasuhiro 
Published: August 2019

Abstract
Eribulin is a synthetic analog of halichondrin B, which is isolated from the marine sponge natural product, as the first halichondrin class of microtubule dynamics inhibitors. Its clinical formulation is currently approved for advanced breast cancer (BC) and advanced liposarcoma in numerous countries. Eribulin shows antitumor activity through cell death induction by an antimitotic effect, and modulation of tumor microenvironment that include vascular remodeling, and reversal of EMT in some of preclinical subcutaneous xenograft models. Effects of eribulin on tumor microenvironment led us to test combination of eribulin with anti-PD1 blockades, and Phase2 clinical study of eribulin in combination with pembrolizumab for metastatic BC patients is in progress. In this study, we investigated antitumor activity of eribulin in combination with anti-PD1 mAb in preclinical mouse BC model using 4T1 cells. Because parent 4T1 cells express P-glycoprotein (Pgp) and eribulin is a substrate of Pgp, we established Pgp-knockout (Pgp-KO) mouse 4T1 BC cells to examine combination antitumor activity of eribulin with anti-PD1 antibody. We used a clone 31 of Pgp-KO 4T1 (#31) cells, which maintains similar tumor phenotypes to parent 4T1 orthotropic transplantation (OT) models, such as growth rate and formation of metastasis. Eribulin inhibited in vitro proliferation of Pgp-KO 4T1 (#31) cells with a lower concentration compared to parent 4T1 cells. Eribulin were intravenous administered at 1 mg/kg with either Q7Dx2 or Q4Dx3 in the combination with anti-PD1 mAb, 200 µg/head, Q3Dx10 in the Pgp-KO 4T1 (#31) OT model (6 mice per a treatment group). Anti-PD1 mAb did not clearly show in vivo antitumor activity. Treatments of eribulin by Q4Dx3 showed enhanced antitumor activity in the combination compared to each single treatment, and all tumors became non-palpable in the combination group. On the other hand, weekly treatments of eribulin did not enhance antitumor activity in the combination with anti-PD1 mAb, although eribulin single treatment significantly inhibited in vivo tumor growth of Pgp-KO 4T1 (#31) tumors. These preclinical results provide preclinical rationale for clinical testing of eribulin in combination with anti-PD1 blockades in patients with BC, and further preclinical analysis of MOA of combination antitumor activity of eribulin with anti-PD1 antibody is warranted.
Citation Format: Taro Semba, Kimiyo Tabata, Yoichi Ozawa, Saori Watanabe Miyano, Junji Matsui, Yasuhiro Funahashi. Antitumor activity of eribulin in combination with anti-PD1 antibody in a mouse syngeneic breast cancer model [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 4089.
Abstract 4091: Evaluating the efficacy of a STING agonist in a murine model of prostate cancer
Authors: Gurkan Jonathan , Choi Jae Eun , Tien Jean , Cieślik Marcin , Franchi Luigi , Chinnaiyan Arul M. 
Published: August 2019

Abstract
Despite the promise of checkpoint inhibitor therapy, prostate cancer has remained resistant to this treatment. Innate immune agonists, however, have been shown to have anti-tumor effects in various cancer types, such as melanoma and colon cancer, and have been nominated to be used in combination with approved anti-PD1/PD-L1 drugs. For instance, STING agonist + anti-PD-1 combination therapy has been demonstrated in a syngeneic mouse model of melanoma. Other innate immune agonists, such as TLR7/8 and TLR9 have also been shown to have potential anti-tumor effects. We hypothesized that innate immune agonists may be effective in the MycCaP syngeneic mouse model of prostate cancer. To compare the efficacy of three innate agonists targeting the STING (3’3’ cGAMP), TLR7/8 (CL097), and TLR9 (ODN2395) pathways, FVB mice were first injected bilaterally with MycCaP subcutaneous tumors. Upon establishment of tumors, mice were administered 3 doses of a single-sided intratumoral injection of each drug. The injected tumors had responses of 50% (6/12), 23% (3/13), and 8% (1/13) for the STING, TLR7/8 and, TLR8 agonists, respectively. Contralateral tumors showed no significant regression.
Published data have reported inherent resistance of MycCaP tumors to anti-PD-1 treatment in vivo. Given our results, we hypothesize that the addition of a STING agonist could enhance efficacy of anti-PD-1 therapy in this model. Mice with MycCaP tumors were administered anti-PD1 alone (n=10) or in combination with bilateral injections of the STING agonist (n=14). Combined therapy resulted in significant reduction in tumor size (71%) compared to anti-PD1 alone (9%). Additionally, there was a significant increase in the Ifnb1 (p=.04), Ifng (p=.008), Tnf-α (p=.006), IRF3 (p=.003) and II6 (p&lt;.0001) gene expression in the combination group showing enhancement of the STING pathway genes. Combined, these findings suggest that targeting the STING pathway may have a modest local anti-tumor effect when compared to other innate immune pathways in prostate cancer. The efficacy of anti-PD-1 therapy was significantly enhanced when combined with a STING agonist, possibly through enhancement STING pathway genes. Our data suggest that combination therapy with a STING agonist and anti-PD1 therapy may have potential anti-tumor efficacy in prostate cancer. Future studies will examine these effects on both local and abscopal tumors.
Citation Format: Jonathan Gurkan, Jae Eun Choi, Jean Tien, Marcin Cieślik, Luigi Franchi, Arul M. Chinnaiyan. Evaluating the efficacy of a STING agonist in a murine model 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 4091.
Abstract 4094: The TLR4 agonist G100 enhances rituximab-mediated ADCC in vitro and has synergistic anti-tumor effects with anti-CD20 mAb in vivo
Authors: Lu Hailing , Betancur Alec , Meulen Jan ter 
Published: August 2019

Abstract
Background: G100, which contains the synthetic TLR4 agonist Glucopyranosyl lipid A (GLA) formulated in a stable oil-in-water emulsion (SE) for intratumoral therapy, is currently in clinical development in combination with pembrolizumab for the treatment of B-cell follicular lymphoma (FL). The current study was undertaken to investigate the interaction of G100 with rituximab, the anti-CD20 mAb that is standard-of-care treatment for FL.
Methods: In vitro studies were performed using peripheral blood mononuclear cells (PBMC) from healthy human donors to investigate the effect of GLA-AF (an aqueous formulation of GLA) on natural killer (NK) cell activation. IFNγ production in NK cells after activation with plate-bound anti-CD16 or target K562 leukemia cells was measured by intracellular cytokine staining (ICS). Rituximab-mediated antibody-dependent cellular cytotoxicity (ADCC) was measured using pretreated or untreated PBMC and rituximab-coated Raji Burkitt’s lymphoma cells as target cells. In vivo studies were carried out in Balb/c mice with bilateral A20 lymphoma. Mice received G100 alone (10μg, intratumoral, 3 injections/week), anti-CD20 alone (clone 5D2, provided by Genentech, 200μg, intraperitoneal, 1 injection/week), or G100+anti-CD20 for a total of 3 weeks.
Results: Incubation of PBMC from 3 different donors with GLA-AF (1 μg/mL) resulted in NK cell activation as demonstrated by increased IFNγ production, as well as enhanced response to the K562 target cells and anti-CD16. When PBMC from 5 normal donors were used in rituximab-mediated ADCC assay, pretreated PBMCs had significantly enhanced lysis of target Raji cells compared to untreated PBMC (p&lt;0.05). In mice with bilateral A20 tumors, the combination of G100 with anti-CD20 resulted in significantly better tumor control and prolonged survival (n=5 per group, p&lt;0.05).
Conclusions: G100 enhances NK cell activity and rituximab-mediated ADCC in human PBMC. Combination of G100 and anti-CD20 mAb has synergistic anti-tumor effects in a mouse lymphoma model. These data support clinical testing of G100 with rituximab in patients with FL.
Citation Format: Hailing Lu, Alec Betancur, Jan ter Meulen. The TLR4 agonist G100 enhances rituximab-mediated ADCC in vitro and has synergistic anti-tumor effects with anti-CD20 mAb in vivo [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 4094.
Abstract 4100: Receptor occupancy and neo-epitope specific T-cell repertoires in patients with solid tissue tumors following anti-PD-1 therapy
Authors: Ashok Devika , Peng Songming , Yuen Benjamin , Walters Matt , Young Stephen W. , Seitz Lisa 
Published: August 2019

Abstract
Background:
In patients undergoing chemotherapy and/or immune therapy, endogenous T cells within the tumor micro-environment (TME) and in the periphery are subject to dynamic changes. Particularly, exhausted T cells in the TME and peripheral blood mononuclear cells (PBMCs) isolated from whole blood express the inhibitory receptor, Programmed Cell Death Receptor 1 (PD-1). A small but significant number of these T cells can recognize neo-epitopes (neoE) arising from patient specific mutations. We determined receptor occupancy (RO) in patients treated with monoclonal anti-PD-1 antibody AB122, which is currently in clinical development.
Methods: Multi-color flow cytometry was used to determine RO post-AB122 administration using a directly-conjugated competitive antibody to AB122. In addition, we determined RO values using the established method for nivolumab using a biotinylated anti-human IgG4 to detect bound anti-PD-1. The assays were also optimized to determine RO in whole blood from patients with solid tumors treated with AB122. Receptor occupancy using both methods were compared. Further, whole exome sequencing from archival formalin-fixed, paraffin-embedded (FFPE) tissue was performed and T cells that recognized patient-specific neoE resulting from tumor-specific mutations were identified in patient blood.
Results:
In the dose-escalation study for AB122 monotherapy arm, a variety of dosing regimens have been evaluated, including Q2W, Q3W and Q4W. The number of doses received ranged from 1 to 20. Data from patients in the 80 and 240 mg Q2W cohorts showed that AB122 serum concentrations ≥1.5 μg/mL (equivalent to 10 nM) are associated with full receptor occupancy. The RO associated with AB122 dosing is maintained when dosed in combination with the potent A2aR/A2bR dual adenosine receptor antagonist AB928 in an ongoing clinical trial.
Conclusions:
Full RO is observed with both cohorts of AB122 monotherapy (80 and 240 mg Q2W) and in the 240 mg Q2W combination with AB928. Study of peripheral target engagement and expansion of neoE-specific T cell populations in a longitudinal study of solid tumor patients treated with AB122 could provide insight towards designing successful combination immune therapy regimens in future clinical trials with AB122.
Citation Format: Devika Ashok, Songming Peng, Benjamin Yuen, Matt Walters, Stephen W. Young, Lisa Seitz. Receptor occupancy and neo-epitope specific T-cell repertoires in patients with solid tissue tumors following anti-PD-1 therapy [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 4100.
Abstract 4117: Novel bead-based multiplex assay for the quantification of human immune checkpoint biomarkers
Authors: Lehmann Jason , Rughwani Priyanka , Zhao Amy , Jiang Weiping , Ji Shaoquan , Sun Binggang 
Published: August 2019

Abstract
Immune checkpoint molecules are important regulators of immune activation. This regulation is critical to maintaining immune homeostasis, and is driven by a complex interplay of both co-stimulatory and inhibitory signals. These checkpoints are key to preventing autoimmunity in healthy individuals; however, cancer cells often exploit this system by modulating the expression of these molecules in order to suppress anti-tumor responses during host immuno-editing. The ability to accurately quantify expression levels of checkpoint molecules is critical to ongoing biomedical research efforts exploring potential therapeutic interventions to overcome tumor-mediated immune-evasion.
To further aid these ongoing research efforts, we have developed a new bead-based multiplex assay panel specifically designed to quantify several human oncology-related immune checkpoint biomarkers including sCD25 (IL-2Ra), GITR, 4-1BB, sCD27, B7.2 (CD86), free active TGF-β1, CTLA-4, PD-L1, PD-L2, PD-1, TIM-3, LAG-3, Galectin-9. The panel utilizes fluorescence-encoded microsphere technology and is designed for use on commonly available flow cytometers. The panel has been extensively validated for specificity, dilution linearity, cross-reactivity, and inter- and intra-assay precision.
This multiplex panel is a robust tool for measuring the concentrations of several immune checkpoint mediators in human serum, plasma, and cell culture supernatant samples, and offers greater efficiency and broader dynamic ranges compared to conventional ELISA-based quantification methods.
Citation Format: Jason Lehmann, Priyanka Rughwani, Amy Zhao, Weiping Jiang, Shaoquan Ji, Binggang Sun. Novel bead-based multiplex assay for the quantification of human immune checkpoint biomarkers [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 4117.
Abstract 4118: Molecular cytometry for immunotherapy trials
Authors: Lomas Woodrow E. , Winters Aidan F. , Alexandre Jason , Martin Jody , Bansal Nidhanjali , Nakamoto Margaret , Gaylord Brent , Saksena Suraj , Chattopadhyay Pratip K. 
Published: August 2019

Abstract
The ability to simultaneously query both protein and mRNA expression on tens of thousands of single cells has emerged only recently, with the development of CITE-seq, REAP-seq, and Ab-seq platforms. Each technology relies on antibodies conjugated to oligonucleotide tags, followed by capture of antibody-stained cells for single cell RNA-sequencing. The technologies have important advantages over flow cytometry, chiefly in that they allow study of a limitless number of parameters, and single cell RNA sequencing, which cannot identify cell populations with as much verity as protein/antibody-based analysis. We characterized the newest molecular cytometry technique (Ab-seq, BD Biosciences) by titrating nearly 100 antibodies (in a single staining experiment and sequencing run), and demonstrated that oligonucleotide antibodies exhibit the same staining characteristics and patterns as flow cytometry antibodies. We also comprehensively examined cells discordant for protein and mRNA expression, in order to discriminate true features of immune cell biology from artifacts caused by drop-out in sequencing assays. Importantly, we also found that mRNA expression could guide the discrimination of cells expressing a protein versus those lacking expression, and define a remarkably low limit of detection for the technology: 1-5 molecules. This remarkable sensitivity will allow detection of cells expressing even the lowest levels of immune exhaustion and checkpoint molecules in cancer immunotherapy trials, and could enable better biomarker discovery than existing technologies. Moreover, this approach allows more detailed characterization of the tumor microenvironment and periphery than ever before. Indeed, in a lymphoma patient, we show that cells expressing both PD1 and CTLA4 carry a unique and specific signature that includes markers never revealed by flow cytometry or other technologies, which might represent new targets for immunotherapy. In sum, this presentation will characterize this new technology and demonstrate the power and promise of new molecular cytometry tools.
Citation Format: Woodrow E. Lomas, Aidan F. Winters, Jason Alexandre, Jody Martin, Nidhanjali Bansal, Margaret Nakamoto, Brent Gaylord, Suraj Saksena, Pratip K. Chattopadhyay. Molecular cytometry for immunotherapy trials [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 4118.
Abstract 4126: Inferring target occupancy from fitting nonlinear-PK data with mechanistic PKRO model for Pembrolizumab
Authors: Hua Fei , Lin Lin , Gruenbaum Lore , Millard Bjorn L. , Burke John M. , Apgar Joshua F. 
Published: August 2019

Abstract
Purpose: Pembrolizumab (Pembro), an anti-PD-1 antibody, has been approved for several cancer indications at 200 mg or 2 mg/kg IV every 3 weeks (Q3W). Understanding the percent target receptor occupancy (RO) for PD-1 at this approved dose can help with dose selection for other anti-PD-1 drugs in development. However, RO can be challenging to determine through direct experimental measurements. A mechanistic PKRO model was developed to fit to Pembro phase 1 PK data and was then used to predict RO at 2 mg/kg IV dosing Q3W.
Methods: A mechanistic PKRO model describes linear clearance of Pembro, tissue distribution of Pembro, binding to PD-1, binding to soluble PD-1 (sPD-1) and clearance of drug-PD-1 complex, clearance of drug-sPD-1 complex as well as drug distribution to tumor and binding to PD-1 in the tumor compartment. Binding between Pembro and PD-1 was fixed to 29 pM (Pembro BLA, Pharmacology Review) and half-life of internalization of drug-PD-1 complex was set to 2 hours.
Results: Since a wide range of sPD-1 concentration has been reported, different sPD-1 concentration was used to fit to the PK data. The model predicted PD-1 expression level in circulation to be approximately 10.8 pM with no soluble PD-1. In the presence of soluble PD-1, PD-1 expression is predicted to be higher to capture the non-linear PK. The model was then used to predict RO at 2 mg/kg IV dosing Q3W and &gt; 98% RO was predicted in the tumor compartment with a range of sPD-1 concentrations from 0 to 3000 pg/mL tested. The impact of Kd and drug-PD-1 turnover rate on predicted RO was explored. When either of the parameters was varied by 10-fold higher or lower from its nominal value, the model still predicted greater than 90% RO at 2 mg/kg dose.
Conclusion: A mechanistic PKRO model was built to capture Pembro phase I PK data and then predicted near complete PD-1 target receptor occupancy at the approved dose. This approach with expanded model scope has the potential to be used to inform dose selection for other anti-PD-1, or I/O therapeutics, as a single therapy or in combination.
Citation Format: Fei Hua, Lin Lin, Lore Gruenbaum, Bjorn L. Millard, John M. Burke, Joshua F. Apgar. Inferring target occupancy from fitting nonlinear-PK data with mechanistic PKRO model for Pembrolizumab [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 4126.
Abstract 4139: Q702, selective Axl, Mer and CSF1R triple kinase inhibitor with dual potentials leading to tumor regression: Immuno-oncology therapy and targeted cancer therapy
Authors: Yang Yeong-In , Kang Hwankyu , Park Dongsik , Jeon Yeejin , Kim Jeongjun , Choi Baejung , Kim Jaeseung , Rho Jinkyung , Lee Jaecheol , Nam Kiyean 
Published: August 2019

Abstract
Functional composition of tumor micro-environment (TME) has been regarded as one of the most important factors in tumor progression. Cancer cells induce immune suppressive condition in TME in order to evade immune system as well as to promote metastasis. Axl, Mer and CSF1R play important roles in making tumor friendly TME by increasing regulatory T cells (Tregs), M2 macrophages, myeloid-derived suppression cells (MDSCs) and suppressing antigen presentation. On the other hand, in cancer cells, overexpression of Axl is reported to have correlation with poor prognosis of patients through promoting epithelial-to-mesenchymal transition (EMT) and inducing drug resistance to chemo or targeted therapy. Q702 is an orally available selective Axl, Mer and CSF1R triple kinase inhibitor under IND enabling studies. In this poster, we present dual potentials of Q702 leading to tumor regression through: 1) immune stimulating activities of Q702 through decreasing Tregs, M2 macrophages, MDSCs population and promoting antigen presentation, 2) direct cytotoxic activity in tumor models including acute myeloid leukemia (AML) and EGFR TKI resistant non-small cell lung cancer (NSCLC).
Citation Format: Yeong-In Yang, Hwankyu Kang, Dongsik Park, Yeejin Jeon, Jeongjun Kim, Baejung Choi, Jaeseung Kim, Jinkyung Rho, Jaecheol Lee, Kiyean Nam. Q702, selective Axl, Mer and CSF1R triple kinase inhibitor with dual potentials leading to tumor regression: Immuno-oncology therapy and targeted cancer therapy [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 4139.