Plasma biomarker analysis of ramucirumab in Japanese patients with advanced gastric cancer.

Abstract

81 Background: Ramucirumab, anti-VEGFR2 receptor antibody, showed significantly improved survivals of gastric cancer in the second line with paclitaxel or single use. Recently we reported early elevation of plasma VEGF-A was associated with shorter survival as a preliminary result. We will report the results of final analysis. Methods: Patients with advanced gastric cancer who received ramucirumab combined with paclitaxel or single use were enrolled. Plasma samples were collected at pre-treatment and day 8 after administration. Nine kinds of plasma biomarker involved in angiogenesis, VEGF-A, C, D, PlGF, VEGFR1, 2, Angiopoietin 1, stromal cell derived factor-1α (SDF1α), and Neuropirin-1, were measured by means of ELISA. Patients were dichotomized by optimal cut-off value. Univariate and multivariate analysis were done by Cox proportion hazard model. Results: Forty-one patients were enrolled. Thirty-nine patients (95.1%) received ramucirumab with paclitaxel. Plasma VEGF-A, D, PlGF, and VEGFR2 levels were significantly increased one week after administration compared with baseline levels, while plasma VEGFR1 and NRP1levels were significantly decreased. Median PFS and OS were 5.6 (95% CI 4.66-6.54) and 9.8 (95% CI 5.41-14.19) months, respectively. In univariate analysis, higher baseline SDF1α and PlGF levels resulted in shorter OS with HR 2.71 95% CI 1.23-6.00, p =0.013 for SDF1α and HR 2.78 95% CI 1.16-6.65, p =0.022 for PlGF. Higher D8 VEGF-A was associated with shorter PFS with HR 2.77 95% CI 1.39-5.51, p =0.004. While higher D8 VEGF-D was associated with better PFS with HR 0.39 95% CI 0.20-0.77, p =0.007. In multivariate analysis, higher baseline SDF1α and PlGF were independent negative prognostic factor for OS with HR 2.45 95% CI 1.10-5.42, p =0.028 for SDF1α and HR 2.48 95% CI 1.03-5.96, p =0.043. With respect to PFS, higher D8 VEGF-A was also independent negative prognostic factor with HR 2.32 95% CI 1.13-4.77, p =0.022, while higher D8 VEGF-D was favorable predictor for PFS with HR 0.47 95% CI 0.23-0.96, p =0.038. Conclusions: Higher base line SDF1α and PlGF levels may be negative prognostic marker. While early VEGF-A and D elevation after ramucirumab administration may be predictive marker of ramucirumab.