Author(s): Di Leo A, Jerusalem G, Petruzelka L, Torres R, Bondarenko IN,
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Abstract PURPOSE: We compared fulvestrant 500 mg regimen with the approved dose of fulvestrant 250 mg per month for treatment of postmenopausal women with estrogen receptor-positive advanced breast cancer who experienced progression after prior endocrine therapy. PATIENTS AND METHODS: Comparison of Faslodex in Recurrent or Metastatic Breast Cancer (CONFIRM) is a double-blind, parallel-group, multicenter, phase III study. Patients were randomly assigned to fulvestrant 500 mg (500 mg intramuscularly [IM] on day 0, then 500 mg IM on days 14 and 28 and every 28 days thereafter) or 250 mg every 28 days. Primary end point was progression-free survival (PFS). Secondary end points included objective response rate, clinical benefit rate (CBR), duration of clinical benefit (DoCB), overall survival (OS), and quality of life (QOL). RESULTS: PFS was significantly longer for fulvestrant 500 mg (n = 362) than 250 mg (n = 374) (hazard ratio [HR] = 0.80; 95\% CI, 0.68 to 0.94; P = .006), corresponding to a 20\% reduction in risk of progression. Objective response rate was similar for fulvestrant 500 mg and 250 mg (9.1\% v 10.2\%, respectively). CBR was 45.6\% for fulvestrant 500 mg and 39.6\% for fulvestrant 250 mg. DoCB and OS were 16.6 and 25.1 months, respectively, for the 500-mg group, whereas DoCB and OS were 13.9 and 22.8 months, respectively, in the 250-mg group. Fulvestrant 500 mg was well tolerated with no dose-dependent adverse events. QOL was similar for both arms. CONCLUSION: Fulvestrant 500 mg was associated with a statistically significant increase in PFS and not associated with increased toxicity, corresponding to a clinically meaningful improvement in benefit versus risk compared with fulvestrant 250 mg.
This article was published in J Clin Oncol
and referenced in Journal of Steroids & Hormonal Science