Bevacizumab in advanced breast cancer

Abstract

The activity of bevacizumab (BVZ) in advanced lines is not well known. In the treatment of metastatic breast cancer, the response rate and time to treatment failure (TTF) decrease with progression through successive therapeutic lines. The objective of this study was to compare BVZ activity in advanced treatment lines with that achieved in the previous line in routine clinical practice. Ninety-six patients who had received BVZ treatment in second or subsequent treatment lines were selected from five Spanish hospitals. Analysis was carried out of the differences in TTF and response rate in the lines with BVZ and those in earlier lines. Data analysis was carried out in two different ways: (a) by comparing treatment groups according to the treatment line received, using a Cox regression model with random effects, and the McNemar test to analysis the response rate, and (b) by comparing intrapatient data, using the Wilcoxon signed-rank test. In 62 patients, the TTF (adjusted for treatment line) was longer in the BVZ treatment line than that in the previous line. In the BVZ lines, there was a significant reduction in the probability of treatment failure [hazard ratio 0.52; 95% confidence interval (CI) 0.38-0.71]. The median TTF was 4.27 months (95% CI 3.7-5) in the previous line and 6.18 months (95% CI 5.5-7.93) in the BVZ line. The percentage of patients with an objective response was 33.3% in the previous lines and 52.1% (P=0.005) in the BVZ line. Contrary to expectation, more patients showed better results with the BVZ line than with the previous line. BVZ treatment in advanced lines improves the results obtained in previous treatment lines. This suggests that BVZ is active in advanced lines and that it produces favourable changes in the natural history of patients with metastatic breast carcinoma.