Phase II trial of fulvestrant with metronomic capecitabine for postmenopausal women with hormone receptor-positive, HER2-negative metastatic breast cancer.

ABSTRACT

BACKGROUND: In this phase II study, we explored efficacy and toxicity of combined endocrine and low-dose metronomic chemotherapy therapy consisting of fulvestrant and capecitabine in estrogen and/or progesterone receptor-positive, HER2-negative MBC. PATIENTS AND METHODS: Patients with ≤ 1 previous hormonal treatment in the metastatic setting received an injection fulvestrant loading dose 500 mg on day 1, 250 mg on days 15 and 29 followed by 250 mg every 28 days along with continuous oral capecitabine in divided doses. The total fixed daily dose of capecitabine was either 1500 mg or 2000 mg, depending on the patient's weight (< 80 kg vs. ≥ 80 kg). Primary end points were PFS and TTP. Toxicity was assessed by continuous evaluations of treatment-emergent adverse events (AEs) and changes from baseline in laboratory values. RESULTS: Forty-one women, with a mean age of 64.5 years, were enrolled. Patients completed a median of 11 monthly treatment cycles. Median PFS was 14.98 months (95% confidence interval [CI], 7.26-upper limit [UL] not estimated) and median TTP was 26.94 months (95% CI, 7.26-UL not estimated). Median overall survival was 28.65 months (95% CI, 23.95-UL not estimated). Treatment was well tolerated with < 10% Grade 3 palmar-plantar erythrodysesthesia. Overall, the most frequent AEs were palmar-plantar erythrodysesthesia, fatigue, and nausea. CONCLUSION: Fulvestrant with metronomic capecitabine demonstrates substantial activity in hormone receptor-positive MBC and is well tolerated. Combined chemoendocrine approaches should be further explored considering the low toxicity of the combination with meaningful TTP.