Phase I/II study of PCI-27483, a coagulation factor VIIa (FVIIa) inhibitor in patients with advanced pancreatic cancer receiving treatment with gemcitabine.

Abstract

221 Background: PCI-27483 is a selective inhibitor of FVIIa, a serine protease activated by interaction with tissue factor (TF). TF upregulation in tumor cells correlates with angiogenesis and a worsened prognosis. Hydrolysis of protease activated receptors by the TF:FVIIa complex induces up-regulation of IL-8 and VEGF. PCI-27483 inhibited the growth of human pancreatic tumors in animal models at a 2.5x to 3.0x change in prothrombin time. PK/INR relationships from a phase I study in healthy volunteers were used to select initial doses of PCI-27483 for the current study. Methods: Patients (pts) with locally advanced or metastatic pancreatic cancer, ECOG performance status 0-1, and normal coagulation were enrolled. All pts in phase I and II receive gemcitabine (G) as a 30-min IV infusion at a dose of 1000 mg/m2 on 3 out of every 4 wks. PCI-27483 is administered twice daily by SC injection. In phase I, doses of PCI-27483 were intra-patient escalated (0.8 to1.2 to1.5 mg/kg) over 4 to 8 wks. The targeted peak INR, measured 2 h postdose, was 3.0. In phase II, pts are being randomized to a control arm to receive G only or to a PCI-27483 arm to receive G plus PCI-27483. Phase I pts receiving 80% of planned doses during in first 6 wks were considered evaluable. Spiral CT scans are performed at 8-wk intervals. Study endpoints: adverse event profile, progression-free survival, venous thromboembolic events, and overall survival. Results: Phase I—8 pts enrolled, 5 pts evaluable. Highest dose of PCI- 27483 achieved was 0.8 mg/kg for 2 pts, 1.2 mg/kg for 3 pts and 1.5 mg/kg for 3 pts. Hematologic toxicity: grade 3 neutropenia (n= 1) or anemia (n = 2). Other grade 3 toxicities: elevated INR (n = 4) or elevated aPTT (n = 1). Dose-level-specific mean 2-h INR values were 2.2 at 0.8 mg/kg (CV=9%; n=7), 3.2 at 1.2 mg/kg (CV=33%; n=6) and 2.9 at 1.5 mg/kg (CV=16%; n=3). No VTEs occurred. Radiologic evaluations of 5 evaluable pts: 4 SD at 16 wks (1st pt SD for >40 wks; 5th pt SD at 8 wks, 16-wk scan pending). Conclusions: PCI-27483 is well tolerated at doses up to 1.5 mg/kg bid with G 1,000 mg/m2. Sustained SDs occurred and INRs were generally within the expected range. The randomized phase II study is ongoing at a dose of 1.2 mg/kg bid. [Table: see text]