Background: Three phase III trials have shown significantly improved progression-free survival (PFS) and response rate (RR) when Bev is combined with first-line chemotherapy for MBC. We conducted a phase II study to evaluate the E2100 Bev-wPac regimen in Japanese MBC patients (pts). Methods: Pts aged ≥20 years with HER2-negative measurable MBC and no prior chemotherapy for MBC received Bev 10 mg/kg d1 and 15 with wPac 90 mg/m² d1, 8, and 15, q4w. Co-primary endpoints were PFS and safety. Secondary endpoints included RR (RECIST v1) and overall survival (OS). We also analyzed efficacy in clinically important subgroups. Results: All 120 planned eligible pts (median age 55 years) were enrolled between Apr 2007 and Jul 2008. Median follow-up is 11.0 months (range 1.4-24.0). Median PFS by independent review committee is 12.9 months (95% CI 11.1-18.2). The table shows PFS and RR subgroup analyses. Median OS is 35.8 months (95% CI 26.4-not reached; 56% of pts still alive). The 1-year OS rate is 89% (95% CI 83-95). Median exposure to Bev and wPac is 10.6 months (range 0.3-24.7). 50 pts (42%) have been treated for ≥1 year. The main reason for discontinuation is progression (45%). First onset of most adverse events was during the first 6 months of therapy. Grade 3 hypertension has been reported in 17% (no grade 4); grade >2 proteinuria is absent; grade 3 and 4 bleeding have occurred in 2% and 1%, respectively. There have been no treatment-related deaths. Conclusions: Bev-wPac therapy showed high activity, similar to that in E2100, in this large single-arm Japanese study. Median PFS in important subgroups, including difficult-to-treat populations such as triple-negative MBC (median 9.6 months), supports findings from the E2100 trial.

* 3 pts without efficacy evaluation excluded.