A randomized, double-blinded, phase II study of paclitaxel/carboplatin (PC) plus CT-322 versus PC plus bevacizumab (Bev) as first-line treatment for advanced nonsquamous non-small cell lung cancer (NSCLC).

Abstract

7584 Background: CT- 322 is a pegylated protein engineered from the tenth type III human fibronectin domain thatspecifically blocks VEGFR-2 signaling by all known ligands. This international randomized study assessed the efficacy and safety of PC + CT-322 compared to PC + Bev as first-line treatment for advanced non-squamous NSCLC. Methods: In addition to paclitaxel 200 mg/m2and carboplatin AUC 6 given on day 1 of a 21 day cycle(maximum 6 cycles), subjects, stratified by ECOG performance status, disease stage, and site, were randomized 1:1 to receive either CT-322 2 mg/kg on days 1, 8, and 15 (arm A) or Bev 15 mg/kg on day 1 and placebo on days 8 and 15 (arm B). CT -322 and Bev/placebo were continued as maintenance until disease progression, unacceptable toxicity, or withdrawal of consent. The primary endpoint was progression-free survival (PFS); secondary endpoints included overall survival (OS), response rate, and safety. Results: 255 subjects were randomized to arm A (n=127) or arm B (n=128). Baseline characteristics were wellbalanced. After a median follow- up of 13.8 months, 9 subjects on arm A and 24 on arm B remained on study treatment. The median treatment duration was 19 weeks in arm A and 26.3 weeks on arm B. The median PFS in arm A was 5.6 months compared to 6.8 months in arm B (HR 1.51, 1 -sided p=0.997). In all prespecified subgroups, PFS was favored in arm B. The response rate was 25.2% in arm A compared to 32.8% in arm B. Median OS was 12.5 months in arm A compared to 15.2 months in arm B. The most common grade ≥ 3 adverse events (Arm A vs B) were neutropenia (47.2% vs 49.2%), thrombocytopenia (11.8% vs 6.3%), and fatigue (10.2% in both arms). Grade ≥ 3 hypertension was more frequently reported in arm A (8.7% vs 3.1%). Grade ≥ 3 venous thrombosis (5.5% vs 6.3%), proteinuria (1.6% vs 2.3%), and bleeding events (0.8% vs 1.6%) were similar. Conclusions: PC + CT-322 failed to improve PFS, OS, or response rate compared to PC + Bev. However, thesafety profile in the PC + CT-322 arm was consistent with the anti-angiogenic mechanism of action, suggesting that CT-322 has biological activity as an inhibitor of VEGFR-2.