Abstract CT093: Axitinib in combination with pembrolizumab (AXI+PEMBRO) in patients (pts) with advanced renal cell carcinoma (aRCC): Analysis of immune-related biomarkers

Abstract

Background: In an open-label, phase Ib dose-finding and dose-expansion study in pts with aRCC, AXI+PEMBRO was tolerable; objective response rate (ORR) was 73.1%, and median progression free survival (mPFS) was 20.9 months (Lancet Oncol. 2018;19:405-15). These planned exploratory analyses evaluated candidate biomarkers that may confer sensitivity/resistance to AXI+PEMBRO. Materials & Methods: Tumor tissue (de novo biopsy or archival), serum and whole blood samples were collected at baseline (BL). Biomarkers were chosen based on known angiogenesis/immunomodulation roles. Clinical outcomes included ORR and PFS. Comparisons for responders vs non-responders were made using Wilcoxon rank sum test. Comparisons of PFS for Results: 52 pts were treated. Tumor tissue, serum and whole blood samples were analyzed from 39 (75.0%), 51 (98.1%) and 52 (100%) pts, respectively. Immunohistochemical analysis of tumor tissue biomarkers revealed no significant associations between CD68, CD8 or PD-L1 levels at BL and ORR or PFS. However, pts whose tumor CD8 % positive cells was ≥median had a numerically longer PFS than pts whose CD8 % positive cells was Conclusions: In pts with aRCC, higher tumor levels of CD8 and serum levels of CXCL10 and CEACAM1 at BL may indicate potential sensitivity to AXI+PEMBRO treatment. Further validation of the value of these biomarkers in an independent cohort with a large sample size is warranted. Citation Format: Michael Atkins, Jean-Francois Martini, Elizabeth Plimack, David McDermott, Igor Puzanov, Mayer Fishman, Daniel Cho, Ulka Vaishampayan, Brad Rosbrook, Kathrine Fernandez, Jamal Tarazi, Saby George, Toni Choueiri. Axitinib in combination with pembrolizumab (AXI+PEMBRO) in patients (pts) with advanced renal cell carcinoma (aRCC): Analysis of immune-related 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 CT093.