PaFLO: Pazopanib with 5-fluorouracil, leucovorin, and oxaliplatin (FLO) as first-line treatment in advanced gastric cancer: A randomized phase II study of the Arbeitsgemeinschaft internistische Onkologie (AIO).

Abstract

TPS4138 Background: VEGF inhibition in gastric cancer shows promising improvement of remission rate and progression-free survival (Ohtsu et al., JCO 2011). Pazopanib is an orally available tyrosine kinase inhibitor (TKI) selectively inhibiting VEGFR-1, -2, -3, c-kit and PDGFR. It is approved for treating renal cell cancer. A phase-I trial showed good tolerability of pazopanib with full-dose FOLFOX in solid tumors (Brady et al., ASCO, 2009). FLO is a widely used combination for advanced gastric cancer recommended in national guidelines. Methods: 75 Patients with HER-2-negative locally advanced or metastatic adenocarcinoma of the stomach or the gastro-esophageal junction will be randomized in a 2:1 ratio to A: FLO (F 2600mg/m2 as 24h infusion, L 200mg/m2, O 85 mg/m2) d1 + pazopanib (800mg) d1-14 and B: FLO; repeated for 12 2-week cycles, followed by a maintenance therapy with pazopanib alone in A and an observation period in B until disease progression. Primary endpoint is progression-free survival rate (PFSR) at 6 months, secondary endpoints are PFSR at 9 and 12 months, median PFS, response rate, duration of response, toxicity, tolerability and overall survival. Additionally, we evaluate the predictive and prognostic relevance of PIGF, VEGF, and the respective soluble receptors sVEGFR1 and sVEGFR2 as biomarkers for clinicopathological parameters, clinical response to treatment and tumor volume change. Based on a phase-III trial demonstrating a 6-month PFSR of 44% with FLO (Al-Batran et al., 2008), we estimate a 6-month PFSR of 55% in the experimental group. Given an alpha error of 0.1 and a beta error of 0.2 in a Simon 2-stage minimax design, in the first stage ≥12 of 30 patients need to be progression free at 6 months to continue and after the second stage ≥25 of 50 patients should be progression free at 6 months to justify further evaluation. Randomization is performed to estimate selection bias according to pazopanib-specific exclusion criteria for comparison with historical data. Study protocol received ethics committee approval in November 2011 and is currently recruiting patients in 15 AIO centers.