Original StudyNetwork Meta-Analysis Comparing Overall Survival for Fulvestrant 500 mg Versus Alternative Therapies for Treatment of Postmenopausal, Estrogen Receptor-Positive Advanced Breast Cancer Following Failure on Prior Endocrine Therapy

BackgroundWe conducted a review of randomized trials to compare the overall survival (OS) with fulvestrant 500 mg versus alternative treatment for estrogen receptor-positive advanced breast cancer following endocrine therapy failure.Materials and MethodsHazard ratios (HRs) were obtained by modeling OS data with the Weibull distribution. A fixed-effect Bayesian network meta-analysis was conducted. The evidence network included anastrozole 1 mg, letrozole 2.5 mg, fulvestrant 250 mg, exemestane 25 mg, megestrol acetate 40 mg, and everolimus 10 mg plus exemestane 25 mg as comparators. Post-antiestrogen and post-aromatase inhibitor subgroup networks were analyzed.ResultsIn the overall analysis, the HRs suggested improved OS for fulvestrant 500 mg versus fulvestrant 250 mg and megestrol acetate 40 mg, and numerically favorable differences with fulvestrant 500 mg versus other comparators. In the antiestrogen subgroup, the HRs suggested improved OS for fulvestrant 500 mg versus fulvestrant 250 mg and megestrol acetate 40 mg; numerical differences in the HRs were seen versus anastrozole 1 mg and letrozole 2.5 mg. In the aromatase inhibitor subgroup, the HRs for OS numerically favored fulvestrant 500 mg versus fulvestrant 250 mg and exemestane 25 mg.ConclusionAcknowledging the limitations of the present network meta-analysis, these findings suggest that fulvestrant 500 mg might provide improved OS versus fulvestrant 250 mg and megestrol acetate 40 mg for treatment of estrogen receptor-positive ABC following endocrine therapy failure. Although OS efficacy versus everolimus 10 mg plus exemestane 25 mg (for overall evidence network), anastrozole 1 mg, exemestane 25 mg, and letrozole 2.5 mg is numerically favorable, additional studies are required to draw formal conclusions.