Nivolumab and Urelumab Enhance Antitumor Activity of Human T Lymphocytes Engrafted in Rag2−/−IL2Rγnull Immunodeficient Mice

Abstract

A current pressing need in cancer immunology is the development of preclinical model systems that are immunocompetent for the study of human tumors. Here, we report the development of a humanized murine model that can be used to analyze the pharmacodynamics and antitumor properties of immunostimulatory monoclonal antibodies (mAb) in settings where the receptors targeted by the mAbs are expressed. Human lymphocytes transferred into immunodeficient mice underwent activation and redistribution to murine organs, where they exhibited cellsurface expression of hCD137 and hPD-1. Systemic lymphocyte infiltrations resulted in a lethal CD4 þ T cell-mediated disease (xenograft-versus-host disease), which was aggravated when murine subjects were administered clinical-grade anti-hCD137(urelumab) and anti-hPD-1 (nivolumab). In mice engrafted with human colorectal HT-29 carcinoma cells and allogeneic human peripheral blood mononuclear cells (PBMC), or with a patientderived gastric carcinoma and PBMCs from the same patient, we found that coadministration of urelumab and nivolumab was sufficient to significantly slow tumor growth. Correlated with this result were increased numbers of activated human T lymphocytes producing IFNg and decreased numbers of human regulatory T lymphocytes in the tumor xenografts, possibly explaining the efficacy of the therapeutic regimen. Our results offer a proof of concept for the use of humanized mouse models for surrogate efficacy and histology investigations of immune checkpoint drugs and their combinations. Cancer Res; 75(17); 3466-78. Ó2015 AACR.

Dual Roles for Regulatory T-cell Depletion and Costimulatory Signaling in Agonistic GITR Targeting for Tumor Immunotherapy

“…As with nearly all novel disease therapeutics, it is difficult to predict with confidence how efficacy in mouse models will translate to human patients. Previous work by Sanmamed and colleagues has shown efficacy of anti-PD-1 and anti-CD137 clinical candidate antibodies in a humanized mouse model where immunodeficient mice were reconstituted with either allogeneic or patient-derived PBMCs at the time of tumor transfer (15). In our experiments testing an anti-human GITR mAb in tumorbearing humanized mice reconstituted with CD34 þ hematopoietic stem cells, we observed both similarities and differences in terms of impact on Tregs as compared with mDTA-1 treatment of conventional tumor-bearing mice.…”

“…Mechanistic preclinical data for a clinical candidate anti-human mAb are generally limited to in vitro or ex vivo studies. Humanized mice are a valuable system to probe the function of immune cell-targeting clinical candidate antibodies in an in vivo setting (15). In this study, we describe such testing for MK-4166, an anti-human GITR mAb currently in clinical testing for cancer immunotherapy.…”

Emerging Opportunities and Challenges in Cancer Immunotherapy

“…We will be developing better, more predictive preclinical models to test immunotherapies including humanized mice implanted with human tumors and human immune systems (98). …”

Humanized Mice as Unique Tools for Human-Specific Studies

“…MHC-mismatched tumor cells resulted in activated immune cells, but no clinical signs of rejection were observedWege et al (2014)CervicalHuman cervical carcinoma cell line (C33a) was subcutaneously engrafted into scid miceHerpes simplex virus type I-based oncolytic treatment in combination with radiation therapy may be an effective treatment for cervical cancerBlank et al (2002)Colorectal Rag2 −/− γc −/− mice were injected with human PBMCs and subcutaneously engrafted on the flank with colorectal carcinoma cell line (HT-29)Co-administration of Urelumab and Nivolumab slowed down tumor growth by elevating activated human T lymphocytes which produced IFN-γ and decreased levels of human regulatory T cells in tumor xenograftsSanmamed et al (2015)GastricPatient-derived xenografts of gastric cancer were subcutaneously engrafted into the right hind flank of scid and nude miceMice engrafted with patient-derived gastric cancers demonstrated identical histological and genetic diversities which corresponded to parental patient tumorsZhang et al (2015)HNSCCNSG mice were injected with expanded HSPCs and engrafted with patient-derived HNSCCHuman immune and stromal cells produced in XactMice mimics patient’s tumor microenvironment. This model was able to reverse genetic drift of tumors that usually occur after serial transplantation in non-humanized miceMorton et al (2016)KidneyNSG mice were engrafted with human RCC cell line (SKRC-59 cells) in the left subrenal capsule of their kidneyHuman anti-CAIX mAbs inhibit RCC growth by halting migration and triggering immune-mediated killing of RCC.…”

“…Optimal dose of ATG in this study was 30 µg, where mice demonstrated mild clinical signs of drug treatment but recovered within 5 hBrady et al (2014)EltrombopagPromacta ® , RevoladeNOD/ scid mice intravenously injected with human CD34 + UCB cellsEltrombopag enhanced expansion and promoted multilineage hematopoiesis of HSPCsSun et al (2012)IpilimumabYervoy ® Newborn NSG were intrahepatically injected with human CD34 + FL/UCB cells within 24 h of birthIpilimumab accelerated rejection of skin graft on humanized miceWaldron-Lynch et al (2012)KM2760–NOG mice were engrafted with human PBMCs and injected with Hodgkin lymphoma cell line (L-428) or cutaneous T-cell lymphoma cell line (HH)Anti-CCR4 mAb could be used to induce anti-tumor activity by removing CCR4-expressing tumors and downregulating regulatory T cellsIto et al (2009)Lamivudine3TCC.B-17- scid engrafted with human thymus and liver tissues under the kidney capsule ( scid -hu Thy/Liv mouse)Relative to untreated mice, intraperitoneal injection of 3TC at 30 mg/kg/day had large reductions in viral RNA from a mean of 10 4.7 to 10 1.8 copies per 10 6 cellsStoddart et al (2014)MiltefosineImpavidoNewborn NSG were engrafted with human CD34 + UBC cells and injected with stationary phase promastigote L. major into the footpadParasitic load was reduced and humanized mice demonstrated side-effects similar to clinical scenariosWege et al (2011)Muromonab-CD3Orthoclone OKT3NSG mice intravenously injected with human PBMCsAdministration of Muromonab-CD3, particularly intravenously resulted in cytokine storm and acute clinical symptoms such as piloerection, hypomotility and hypothermiaBrady et al (2014)NivolumabOpdivo ® RAG2 −/− γc −/− mice intravenously injected with human PBMCsIn mice engrafted with human colorectal HT-29 carcinoma cells and allogeneic human PBMCs, co-administration of Nivolumab and Urelumab slowed tumor growthSanmamed et al (2015)OseltamivirTamiflu ® RAG2 −/− γc −/− mice intraperitoneally injected with H7N9No therapeutic effe...…”