The addition of bevacizumab to first-line chemotherapy extended 1-year OS among patients with HER-2–negative, metastatic breast cancer, according to results of a meta-analysis.
Prior studies have shown the addition of bevacizumab (Avastin, Genentech) to first-line chemotherapy consistently improves response rate and PFS in this patient population. However, previous research has not demonstrated a significant OS difference, and researchers have been unable to determine which patients would benefit most from bevacizumab.
In the current study, researchers evaluated data from three randomized phase 3 trials that included a combined 2,447 patients with HER-2–negative metastatic disease. The investigators focused on the efficacy of the bevacizumab-chemotherapy regimen in poor-prognosis patients.
Overall, the addition of bevacizumab to chemotherapy extended median PFS (9.2 months vs. 6.7 months; HR=0.64; 95% CI, 0.57-0.71) and improved response rate (49% vs. 32%). Patients assigned to the combination regimen also demonstrated longer median OS (26.7 months vs. 26.4 months; HR=0.97; 95% CI, 0.86-1.08).
Among patients with triple-negative disease, those assigned to the combination regimen demonstrated longer median PFS (8.1 months vs. 5.4 months; HR=0.63; 95% CI, 0.52-0.76) and median OS (18.9 months vs. 17.5 months; HR=0.96; 95% CI, 0.79-1.16). One-year OS rates were 71% for bevacizumab-treated patients and 65% for those who did not receive bevacizumab.
“Bevacizumab improves efficacy, including 1-year OS rates, both overall and in subgroups of poor-prognosis patients with limited treatment options,” the researchers concluded.