CHICAGO – For women with estrogen receptor–positive breast cancer resistant to endocrine therapy, the combination of everolimus and exemestane had better efficacy than did everolimus alone, but single-agent capecitabine appeared to offer benefit comparable to that of the combination therapy, results of the BOLERO-6 trial suggest.
Among 309 postmenopausal women with ER-positive, HER2-negative advanced breast cancer, the combination of everolimus (Afinitor) and exemestane (Aromasin and generics) was associated with a 26% improvement in progression-free survival (PFS) compared with everolimus alone, reported Guy Jerusalem, MD, PhD, of Liege University, Belgium.
There was also, however, a numerical but not statistically significant difference in PFS favoring capecitabine (Xeloda and generics) “which may be attributed to various baseline characteristics favoring capecitabine, and potential informative censoring,” he said at the annual meeting of the American Society of Clinical Oncology.
“We have noted in BOLERO-6 a better-than-expected outcome in median progression-free survival of capecitabine compared with the previously reported 4.1 to 7.9 months median progression-free survival,” he said.
BOLERO-6, results of which were published online June 3 in, was a postmarketing study by the sponsors to fulfill commitments to both the Food and Drug Administration and the European Medicines Agency to estimate the treatment benefit with combined everolimus and exemestane vs. monotherapy with everolimus or capecitabine in patients with ER-positive, HER2-negative breast cancer that progressed during nonsteroidal aromatase inhibitor therapy.
Patients from 83 centers in 18 countries were enrolled in the open label, phase 2 study and randomly assigned to receive oral everolimus 10 mg daily with oral exemestane 25 mg daily, everolimus at the same dose alone, or oral capecitabine 1,250 mg/m2 twice daily for 2 weeks on, 1 week off.