Abstract 5016: Antitumor activity of anti-PD-1 in combination with tyrosine kinase inhibitors in a preclinical renal cell carcinoma model
Authors: Masters Gregg , Dito Gennaro , Penhallow Becky , Lewin Anne , Kao Henry , Jure-Kunkel Maria N. 
Published: May 2015

Abstract
Introduction: Nivolumab (BMS-936558; MDX-1106; ONO-4538) is a fully human IgG4 programmed death-1 (PD-1) immune checkpoint inhibitor antibody that selectively prevents interaction with PD-1 ligands (PD-L1 and PD-L2), inhibiting the downregulation of antitumor T-cell functions. Nivolumab has shown activity in advanced solid tumors, including renal cell carcinoma (RCC), melanoma, and non-small cell lung cancer (Topalian SL, et al. NEJM 2012;366:2443-54). Sunitinib and sorafenib are anti-angiogenic tyrosine kinase inhibitors (TKIs) used for the treatment of RCC. We investigated the activity of nivolumab in combination with TKIs in a preclinical RCC murine model. Methods: The murine RCC (Renca) tumor cell line was maintained in vitro and implanted subcutaneously into 8-12 week old female Balb/c mice. When mean tumor volume reached approximately 90-100 mm3, mice were randomized into groups of eight. Vehicle control, sunitinib 120 mg/kg, or sorafenib 200 mg/kg were administered orally once daily for 14 days. The nivolumab surrogate antibody, an IgG1 anti-mouse PD-1 monoclonal antibody (clone 4H2), was administered at 10 mg/kg by intraperitoneal injection every four days for four cycles. Immunohistochemistry and flow cytometry analyses were used to assess immune cell infiltration of tumors. Results: Sunitinib monotherapy showed activity in the Renca murine RCC model producing tumor growth inhibition of 84% by the end of treatment; however, tumors grew progressively after cessation of therapy. Conversely, while the anti-PD-1 monoclonal antibody was inactive in this model, addition of anti-PD-1 to sunitinib produced significant antitumor activity, resulting in complete tumor regressions or marked delay in tumor growth. Combination anti-PD-1 plus sunitinib therapy also had no effect on the body weight of the mice. Immunohistochemical analysis demonstrated that sunitinib monotherapy led to an influx of immune cells predominantly into the tumor periphery, whereas greater infiltration of immune cells throughout the tumor was observed with combination anti-PD-1 and sunitinib therapy. In contrast, combination treatment with anti-PD-1 antibody and sorafenib did not enhance antitumor activity in this murine RCC model. Further exploration of the mechanisms contributing to this synergy will be presented. Conclusions: Combination therapy with sunitinib and anti-PD-1 antibody demonstrated an enhanced effect against murine RCC. Safety and response to nivolumab plus sunitinib, pazopanib, or ipilimumab in patients with metastatic RCC are being assessed in an ongoing phase 1 study (NCT01472081).
Citation Format: Gregg Masters, Gennaro Dito, Becky Penhallow, Anne Lewin, Henry Kao, Maria N. Jure-Kunkel. Antitumor activity of anti-PD-1 in combination with tyrosine kinase inhibitors in a preclinical renal cell carcinoma model. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5016. doi:10.1158/1538-7445.AM2014-5016