Correlative analyses of plasma cytokine/angiogenic factor (C/AF) profile, gender and outcome in a randomized, three-arm, phase II trial of first-line vandetanib (VAN) and/or carboplatin plus paclitaxel (CP) for advanced non-small cell lung cancer (NSCLC)

Abstract

7593 Background: VAN (ZD6474) is an oral inhibitor of VEGFR, EGFR and RET. In a phase II trial, 181 patients with advanced NSCLC were randomized to 1st-line treatment with VAN, CP or VAN + CP. Progression free survival (PFS) was prolonged for VAN + CP vs CP (Heymach et al, submitted for ASCO 2007). Exploratory subgroup analyses suggest gender differences in PFS benefit for VAN + CP vs CP (HR 0.47 in females vs 1.05 in males). We performed exploratory analyses of plasma levels of 35 C/AFs to investigate gender differences and potential prognostic or predictive markers. Methods: Plasma was collected at baseline (n = 123; VAN 55, CP 32, VAN + CP 36), day (D) 8 (n = 104), D22 (n = 95), and D43 (n = 83). We used multiplex bead assays to measure 33 plasma C/AFs, including VEGF, basic FGF, EGF, HGF, E-selectin, ICAM-1, MMP-9, multiple chemokines and interleukins (IL). Osteopontin and sVEGFR-2 were measured by ELISA. Cox models were applied on PFS to identify prognostic/predictive markers after rank transformation and adjusted for covariates. Results: Significant gender differences in baseline C/AF levels were seen for IL-15, IL-1RA, IL-2R, MIG, and MIP-1A (all higher in females, all p = 0.022). Controlling for gender and treatment, high baseline E-selectin (p = .01), IL-6 (p = 0.018), and IL-2R (p = 0.008) were adverse prognostic indicators for PFS. Controlling for gender, the tests for treatment by factor interactions (to assess whether treatment effect was different in patients with low and high C/AF levels) were significant for baseline HGF (p = 0.04) and IL-2R (p = 0.008). For both HGF and IL- 2R, low levels were associated with prolonged PFS in the VAN arm, but were not associated with differences in the CP or VAN + CP arms. Significant changes in VEGF (rise) and sVEGFR-2 (decrease) occurred with treatment in the VAN arm; IL12, IL-1RA, MMP-9 and MCP-1 changed in the CP and VAN + CP arms. Conclusions: There are gender differences in PFS benefit from VAN and in plasma C/AF profile. Several C/AFs were of prognostic value, whereas low HGF and IL-2R were predictive of benefit in the VAN but not CP and VAN + CP arms. These gender differences and markers warrant further investigation. [Table: see text]