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331 Phase I Study of the “Triad� Autologous (FANG™) Vaccine, Incorporating Bifunctional shRNAfurin and GMCSF Transgene Expression, in Advanced Cancer Patients Molecular Therapy Volume 20, Supple[.]
CANCER – IMMUNOTHERAPY: HARNESSING GENE THERAPY TO IMPROVE ANTI-TUMOR EFFECT 329 Redirection of TH17 Cells with a Car Containing the ICOS Costimulatory Domain Enhances Function, Antitumor Activity and Persistence of TH17 Cells Sonia Guedan,1 Carmine Carpenito,1 Shannon E McGettigan,1 Matthew J Frigault,1 John Scholler,1 Yangbing Zhao,1 Carl H June.1 Abramson Family Cancer Research Institute and Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA Adoptive transfer of large numbers of Th17 cells polarized and expanded in vitro is an attractive therapy for the treatment of cancer CD278, the inducible costimulator (ICOS) has been shown to be critical for the sustained expansion of human Th17 cells after their primary activation We analyzed whether incorporation of the ICOS intracellular domain in a chimeric antigen receptor can promote Th17 phenotype after antigen priming and enhance the antitumor activity of engineered T cell therapies Th17 polarized cells were engineered to express a single-chain variable fragment that binds mesothelin (SS1) fused to the T cell receptor- ζ signal transduction domain in tandem with the CD28, CD137 (4-1BB) or CD278 (ICOS) intracellular domains When stimulated with aAPC or tumor cells expressing mesothelin, Th17 cells redirected with the SS1-ICOS-z chimeric receptor secreted high amounts of IL17A, IL17F and CCL20 but nominal levels of IL-2 Moreover, Th17 activation through ICOS induced the expression of CD161, consistent with a predominant Th17 phenotype By contrast, Th17 cells redirected with the SS128-z, secreted higher amounts of IL-2 and IFNg but nominal levels of IL17A and IL17F, and had low CD161 expression When transferred into NSG mice with large vascularized pre-established tumors, Th17/Tc17 cells redirected with SS1-ICOS-z mediated enhanced antitumor responses, with 70% of mice showing complete remission Importantly, incorporation of the ICOS intracellular domain in the CAR significantly increased Th17 cell persistence post infusion when compared with the incorporation of CD28 or 4-1BB intracellular domains Incorporation of the ICOS signaling domain in CAR T cells imparts novel functions compared to CARs encoding CD28 or 4-1BB signaling domains Our studies indicate that redirection of Th17 cells with a CAR encoding the ICOS intracellular domain is critical for obtaining potent Th17 cells with enhanced function and persistence The design of novel ICOS-based CARs has the potential to augment antitumor effects in clinical trials 330 Tumor Pericytes: A Novel Target for Immunotherapy in Renal Cell Carcinoma Nina C Sabins,1 Anamaka Bose,1 Walter J Storkus.1 Dermatology, University of Pittsburgh, Pittsburgh, PA Tumor vasculature is classified by leaky, chaotic blood vessels consisting of several components including vascular endothelial cells (VEC) and mural cells (smooth muscle cells and pericytes), as well as immune regulatory cells, stem cells and vascular progenitors An irregular tumor vasculature limits immune effector cell access to the tumor, and may in part be responsible for the modest success observed in many current anti-cancer immunotherapies Certain inhibitory drugs targeting tyrosine kinase receptors expressed on tumor stromal cells induce a Type-1 proinflammatory skewing of the tumor microenvironment (TME) with a coordinate reduction in the number of regulatory immune cell populations A transient remodeling of the vasculature may also occur in association with enhanced (pro-inflammatory) leukocyte recruitment We have shown by quantitative PCR that the cell-surface antigen delta-like kinase-1 (DLK1), a progenitor cell marker, is exclusively expressed by tumorassociated pericytes, and is absent from other tumor stromal cell populations, including VEC and the tumor cells themselves DLK1 is S130 also not expressed by vascular pericytes isolated from normal somatic tissues, such as kidney Little is currently known regarding pericyte biology in the TME, with no existing treatments specifically targeting this cell population We hypothesize that vaccination against antigens expressed preferentially by tumor pericytes will result in vascular remodeling and improved delivery of protective Type-1 T cells into the TME Using a prediction algorithm, we have identified candidate peptide epitopes derived from DLK1 presented by H-2Kd or H-2Ld to CD8+ T cells in BALB/c mice We have now shown that BALB/c mice bearing established RENCA (renal cell carcinomas) exhibit profoundly suppressed tumor growth after therapeutic vaccination with syngeneic dendritic cells pulsed with DLK1-derived peptides Mice receiving control vaccines exhibited progressive tumor growth indistinguishable from untreated, tumor-bearing animals We believe that immune-based targeting of the tumor pericytes as a consequence of specific vaccination (against antigens like DLK1) has significant translational merit for the treatment of vascularized, solid cancers 331 Phase I Study of the “Triad” Autologous (FANG™) Vaccine, Incorporating Bifunctional shRNAfurin and GMCSF Transgene Expression, in Advanced Cancer Patients Neil Senzer,1,2,3,4 Minal Barve,1 Cynthia Bedell,1 Joseph Kuhn,5 Peter Beitsch,2 Robert Steckler,2 Robert Hebeler,6 Mitchell J Magee,2 Walton Taylor,2 Brian M Gogel,2 Padmasini Kumar,4 Phillip B Maples,4 John Nemunaitis.1,2,3,4 Mary Crowley Cancer Research Centers, Dallas; 2Medical City HCA, Dallas; 3Texas Oncology, P.A., Dallas; 4Gradalis, Inc., Dallas; 5WLS Surgery Associates, P.A., Dallas; 6Baylor Medical Center, Dallas This non-randomized Phase I study of the autologous FANG™ vaccine expands the “triad” concept of de-tolerizing and augmenting the afferent arm of the immune response (i.e autologous tumor antigen incorporation, GMCSF enhanced antigen presentation and processing, and suppression of endogenous immunosuppression) It contains a plasmid encoding both GMCSF and an RNA interference moiety, bifunctional shRNAfurin, that targets and downregulates the proprotein convertase Furin resulting in knockdown of both TGFb1 and b2 The bi-shRNA technology is designed to maximize target inhibition via simultaneous mRNA cleavage, translational repression and p-body sequestration Briefly, the vaccine was cGMP manufactured following autologous tumor tissue harvest from a medically indicated procedure at Gradalis, Inc Depending on cell yield of dose levels of vaccine was produced (1 x 107 and 2.5 x 107 cells/injection) The vaccine was administered intradermally once a month (5-12 doses) gIFN ELISPOT was assessed following PBMC co-incubation with the patient’s irradiated, autologous FANG™ vaccine at baseline, Month 4, and individual follow up time points Thirty-one of 58 harvested patients with advanced, previously treated cancer were treated (27 were not for the following reasons: vaccine failures, insufficient tissue, benign lesion, 17 pursued other options, repeat harvest but not treated) Vaccine manufacturing success was 88% There were no treatment-related serious adverse events (SAE); Grade 1/2 AE were limited to local reactions Postmanufacturing quality control assays of vaccines assessed GMCSF, Furin, TGFb1 and -b2 expression pre-versus post-transfection Mean GMCSF production post transfection was 1108 pg/106 cells/mL The mean Furin knockdown was 85.09% and the mean TGFb1 and -b2 knockdown was 93.5% and 92.5%, respectively Median survival of FANG™-treated versus non-treated patients was 554 and 132 days from time of procurement (p