A double-blind, placebo-controlled, randomized phase III trial of gemcitabine (G) plus bevacizumab (B) versus gemcitabine plus placebo (P) in patients (pts) with advanced pancreatic cancer (PC): A preliminary analysis of Cancer and Leukemia Group B (CALGB

Abstract

4508 Background: In a phase II trial in 52 PC pts, GB yielded a 21% response rate and a median survival of 8.8 months (mo) (Kindler, JCO 2005). These data led CALGB to conduct a phase III trial of GB vs. GP in advanced PC pts. Methods: This randomized trial was double-blind, placebo-controlled. Eligible pts had no prior therapy for advanced disease, PS 0–2, no tumor invasion of adjacent organs, no increased bleeding risk. Primary endpoint: overall survival (OS). Stratification: PS (0/1 or 2), disease extent (locally advanced or metastatic), prior radiation (RT) (yes/no). Statistics: 90% power to detect a difference in median OS of 6 vs. 8.1 mo. Treatment: Pts received G 1,000 mg/m2 over 30 minutes days (D) 1, 8, 15 Q28D; B 10 mg/kg or P D 1, 15 Q28D. CT scans: Q2 cycles. Results: 602 pts enrolled 6/30/04–4/14/06. Based on a protocol-specified interim analysis with 64% of information on OS, the CALGB Data Safety Monitoring Board released study data in 6/06 because a futility boundary was crossed. Pts on treatment were notified and unblinded. Pt characteristics (302GB/300GP): male 58%/51%; median age 63.8/65.0; PS 2 9%/9%; stage IV 85%/84%; prior RT 11%/11%. Median follow-up: 11.3/11.7 mo. As of 12/22/06, 436 pts (224/212) have died (93% of total expected deaths at planned final analysis). Median OS 5.7/6.0 mo (95% CI: 4.9, 6.5/5.0, 6.9). Median failure-free survival 4.8/4.3 mo (95% CI: 4.3, 5.7/3.8, 5.6). Response (includes unconfirmed responses): complete (CR) 1.9%/3.0%; partial (PR) 11.2%/8.3%, stable disease (SD) 40.7%/35.7%. Disease control rate (CR/PR/SD) 54%/47%. 525 pts (268/257) are currently evaluable for toxicity. Median cycles 3.5/3.1 (p=0.09). Total mg/m2 G received 9095/8334 (p=0.22). Grade ¾ toxicity (%pts GB/GP): neutropenia 33%/30%; anemia 5%/8%; thrombocytopenia 12%/12%; hypertension 8%/2%; perforation 0.4%/0%; GI bleed 3%/2%; CVA 2%/2%; proteinuria 4%/1%; venous thrombosis 9%/9%. Conclusion: The addition of B to G does not improve survival in advanced PC. [Table: see text]