Final analysis of a phase IB/randomized phase II study of gemcitabine (G) plus placebo (P) or vismodegib (V), a hedgehog (Hh) pathway inhibitor, in patients (pts) with metastatic pancreatic cancer (PC): A University of Chicago phase II consortium study.

4012 Background: Sonic Hh (SHh), the ligand for the Hh pathway, is over-expressed in >80% of PC. V had activity in preclinical murine PC models leading to increased tumor perfusion, enhanced tumor delivery of G, and an improvement in survival. Methods: We conducted a placebo-controlled, phase IB/randomized phase II trial of GV or GP. Eligible pts, KPS 80-100, had untreated metastatic PC, or had completed adjuvant therapy > 6 months (mo) prior. Primary endpoint: progression-free survival (PFS). Correlatives: serial SHh serum levels; serial perfusion CT imaging. All pts received G 1000mg/m2over 30 minutes, days (D) 1, 8, 15, Q28D. A lead-in phase IB was performed. Pts, stratified by KPS (80 v 90/100), and disease status (newly diagnosed/recurrent), were randomized to V (150 mg PO daily) or P. For pts on P, cross-over was allowed at progression. Assuming a mPFS of 3.5 months for GP and 5.7 months for GV (HR=0.61), a sample size of 106 subjects (53 per group) provided 85% power to detect this difference, usin...