Abstract 1306: Biomarker results from a clinical trial of nivolumab in patients (pts) with metastatic renal cell carcinoma (mRCC) (CA209-009): Gene expression, serum profiling for immune markers, and multiplex tissue immunohistochemistry (IHC) (2015)

Abstract Background. A prospective study of the programmed death-1 (PD-1) inhibitor nivolumab, which shows clinical activity in mRCC (Motzer RJ, et al. JCO, 2014), reported changes in serum chemokines (CXCL9, CXCL10) and tumor T cell infiltrates consistent with PD-1 inhibition (Choueiri TK, et al. ASCO 2014; abstract 5012). Here we expand on these findings to report on immune biomarkers in tumor biopsies and peripheral blood. Methods. Ninety-one eligible pts who had RCC with a clear cell component and measurable disease received nivolumab intravenously on day 1 of each 3 week treatment cycle. Previously treated pts were randomized to 0.3 (n = 22), 2 (n = 22), or 10 mg/kg (n = 23) nivolumab; treatment-naïve pts (n = 24) received 10 mg/kg. IHC was performed on tumor biopsies obtained at baseline (BL) and at cycle 2 day 8 (C2D8) to quantify cells bearing T cell markers (CD3/CD4/CD8/FoxP3/PD1); matched specimens were available for 53 pts. Gene expression (18,562 loci; Affymetrix) was analyzed in biopsies and peripheral whole blood obtained at BL and on treatment. Pharmacodynamic effects on transcription were evaluated for connection to immune cell lineages (Abbas AR, et al. Genes and Immunity, 2005) and for biological impact (MetaCore). Serum at BL and time points through C4D1 was analyzed for markers of inflammation (53 analytes; Myriad RBM) and antibodies against tumor antigens (30 antigens; Serametrix). Results. IHC (n = 53 pairs) revealed a significant (P &lt; 0.01) increase in CD8+ T cells while median levels of FoxP3+/PD1+ CD4+ T cells remained &lt; 1%. Tumor expression profiling also demonstrated an on-treatment increase (&gt; 1.3-fold; P &lt; 0.01) for activated CD8+ T cell transcripts (CD8A/B, CD3D/E/G/Z, CTLA-4) and indicated enrichment for both lymphoid and myeloid lineages. Pathway analysis identified an impact on interferon signaling and on multiple components of MHC class I antigen presentation, including the antigen processing factors TAP1 and PSMB9. In peripheral blood, transcripts for T cell markers (TRAC, TRBC2, CD3G) showed significant decreases (&gt; 1.2-fold, P &lt; 0.01) at C1D2, while multiple IFNγ-responsive genes were up-regulated. Few (&lt; 30) substantive differences in pharmacodynamic effects on transcription were detected between treatment arms. At C2D8 (n = 70), serum levels of the immune markers IL8, IL18, TNFR2, MIP1β, and CD25 had increased by &gt; 30%. By C4D1, 22/61 (36%) pts demonstrated increased seroconversion against ≥ 5 tumor antigens. Conclusions. In this first biomarker-based study of an immune checkpoint inhibitor in mRCC, immunomodulatory effects consistent with PD-1 inhibition were seen in peripheral blood and the tumor microenvironment. Ongoing phase 3 studies will provide additional evidence of the effect of nivolumab on these biomarkers (NCT01668784, NCT02231749). Citation Format: Toni K. Choueiri, Mayer N. Fishman, Bernard Escudier, Walter M. Stadler, Scott Chasalow, Petra Ross-Macdonald, Maria Jure-Kunkel, Mario Sznol, Jason S. Simon. Biomarker results from a clinical trial of nivolumab in patients (pts) with metastatic renal cell carcinoma (mRCC) (CA209-009): Gene expression, serum profiling for immune markers, and multiplex tissue immunohistochemistry (IHC). [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1306. doi:10.1158/1538-7445.AM2015-1306