Abstract S6-5: Primary results of BEATRICE, a randomized phase III trial evaluating adjuvant bevacizumab-containing therapy in triple-negative breast cancer

Abstract

Abstract Background: Bevacizumab (BEV), an anti-VEGF antibody, significantly enhanced progression-free survival in metastatic breast cancer (BC) (E2100, AVADO, RIBBON-1, RIBBON-2) and pathologic complete response rates in the neoadjuvant setting (GeparQuinto, NSABP B-40) when combined with chemotherapy (CT). The dependence of micro-metastases on angiogenesis [Holmgren 1995] suggests that patients might benefit from anti-angiogenic strategies applied in the adjuvant setting. The BEATRICE trial was designed to test this hypothesis in patients with triple-negative BC, who have a poor prognosis and lack targeted options for treatment. Methods: In this open-label randomized multinational phase III trial, patients with centrally confirmed triple-negative operable primary invasive BC (pT1a-pT3) were randomized 1:1 after definitive surgery to receive ≥4 cycles of either CT alone or the same CT + 1 year of BEV 5 mg/kg/wk equivalent. CT was anthracycline [anth] and/or taxane-based. Patients were stratified by nodal status (0 vs 1–3 vs ≥4 involved nodes), CT backbone (anth vs anth + taxane vs taxane), hormone receptor status (negative vs low), and surgery (breast-conserving vs mastectomy). The primary objective is to compare invasive disease-free survival (IDFS) [Hudis 2007] with adjuvant CT ± 1 year of BEV. Secondary outcome measures are overall survival (OS), breast cancer-free interval, disease-free survival (DFS), distant DFS, and safety (NCI CTCAE v3.0). The sample size was calculated to provide 80% power for a HR=0.75 at α=0.05 assuming 5-year IDFS of 72.0% with CT vs 78.2% with CT + BEV with 388 events. BEATRICE also includes evaluation of potential predictive and prognostic biomarkers. Results: Between Dec 2007 and Mar 2010, 2591 patients were randomized. At data cut-off (Feb 29, 2012), median follow-up was 32 months. The mean CT exposure was balanced between treatment arms. Median BEV duration was 11.7 months. BEV was associated with an increased incidence of grade ≥3 congestive heart failure/left ventricular dysfunction (3% vs <1% with CT), grade ≥3 hypertension (12% vs <1%), and treatment discontinuation (BEV and/or CT: 20% vs 2%) but no increase in the risk of fatal adverse events (0.3% vs 0.2%). No new safety signals were observed. Conclusion: There was no statistically significant improvement in IDFS with the addition of 1 year's BEV to adjuvant CT for triple-negative BC. Further follow-up is required to assess the impact of BEV on OS. The safety profile was consistent with previous reports in metastatic BC with a low incidence of fatal adverse events. Protocol-specified biomarker analyses are ongoing. Updated OS results are expected in 2013. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr S6-5.