Fulvestrant 500 mg may extend overall survival compared with anastrozole 1 mg as first-line endocrine therapy for advanced breast cancer, a new study published online ahead of print in the Journal of Clinical Oncology has shown.1

For the open-label, multicenter, phase 2 FIRST trial, researchers enrolled 205 postmenopausal women with estrogen receptor-positive, locally advanced or metastatic breast cancer who had not received prior therapy for advanced disease.

Patients were randomly assigned to receive fulvestrant 500 mg on days 0, 14, 28, and every 28 days thereafter, or anastrozole 1 mg daily.

Previously reported results showed that the clinical benefit rate was 72.5% with fulvestrant and 67.0% with anastrozole. The median time to progression was 23.4 months and 13.1 months, respectively.

Here, the investigators report overall survival after about 65% had died. At data cutoff, 61.8% of the fulvestrant group had died compared with 71.8% of the anastrozole group (HR = 0.70; 95% CI: 0.50-0.98; P=0.04). Median overall survival was 54.1 months with fulvestrant vs 48.4 months with anastrozole.

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The authors note that several limitations exist in the overall survival analysis; however, the present results suggest that fulvestrant extends overall survival vs anastrozole.

“This finding now awaits prospective confirmation in the larger phase III FALCON (Fulvestrant and Anastrozole Compared in Hormonal Therapy Naïve Advanced Breast Cancer) trial,” the authors wrote.

Reference

  1. Ellis MJ, Llombart-Cussac A, Feltl D, et al. Fulvestrant 500 mg versus anastrozole 1 mg for the first-line treatment of advanced breast cancer: overall survival analysis from the phase II FIRST study [published online ahead of print September 14, 2015]. J Clin Oncol. doi: 10.1200/JCO.2015.61.5831.