A randomized phase II and coagulation study of bevacizumab alone or with docetaxel in patients with previously treated metastatic pancreatic adenocarcinoma

Abstract

4556 Background: Vascular endothelial growth factor (VEGF) is overexpressed in pancreatic cancer and interacts with coagulation to promote angiogenesis. We performed this randomized phase II study of bevacizumab (BEV) alone or with docetaxel (DOC) in patients (pts) with previously treated metastatic pancreatic adenocarcinoma to investigate their clinical activity and interaction with coagulation. Methods: Eligible pts had one prior gemcitabine regimen, PS 0–1, measurable disease, and no bleeding/thrombosis. BEV was given at 10 mg/kg IV Q 2 weeks alone (Arm A) or with DOC (Arm B) at 35 mg/m2 IV on days 1, 8, and 15 Q 28 days. CT scans were obtained every 2 cycles. The primary endpoint was progression-free survival (PFS), with secondary endpoints response rate and overall survival (OS). Peripheral blood was obtained for coagulation parameters, basic fibroblast growth factor (bFGF), VEGF, and circulating endothelial cells (CEC). A two-stage design with a target median PFS of =4 months in either arm and early stopping for futility was utilized. Results: Thirty pts (15 per arm) received 88 cycles of therapy (44 per arm, median 2, range <1–10). Pt characteristics: median age 61.5 (range 38–81), ECOG 0/1 (11/19). Seven pts in Arm A and 8 in Arm B had grade 3/4 events. Serious adverse events were 5 DVT/PE (3-Arm A; 2-Arm B) and 2 bowel perforations (1 per arm). Best reponse was 4 pts with stable disease in Arm A and 5 pts with stable disease and one unconfirmed PR in Arm B. Median PFS and OS were 43 and 181 days in Arm A and 45 and 123 days in Arm B (p=0.5 for PFS, p=0.8 for OS). The study was stopped after only 2/15 pts per arm had PFS of =4 months. In multivariate analysis, higher bFGF (HR=1.4, p=0.008) and thrombin/antithrombin complex (TAT) levels on treatment (HR=1.75, p<0.001) were associated with worse OS. D-dimer, tissue factor and TAT levels on d15 were associated with increased venous thrombosis and GI perforation (p=0.04). VEGF plasma levels and CEC at all time points were not associated with clinical outcomes. Conclusions: BEV alone or with DOC has minimal antitumor activity in gemcitabine-refractory pancreatic cancer. Increased plasma bFGF and coagulation markers during therapy predict for worse OS and increased perforation and thrombosis. [Table: see text]