Low dose capecitabine plus weekly paclitaxel in patients with metastatic breast cancer: a multicenter phase II study KBCSG-0609

Purpose The combination of capecitabine and paclitaxel (XP) has demonstrated synergistic antitumor activity in preclinical models. The purpose of this phase II study was to evaluate the efficacy and safety of a monthly XP regimen in patients with metastatic breast cancer (MBC). Methods Eligible patients had received one or fewer prior chemotherapy regimens for MBC. Patients received oral capecitabine of low dose (828 mg/m 2 twice daily, days 1–21) plus paclitaxel (80 mg/m 2 , i.v., over 60 min, days 1, 8 and 15) every 28 days until disease progression or unacceptable toxicity. The primary endpoint was overall response rate (ORR). Progression-free survival (PFS), overall survival (OS) and safety were secondary endpoints. An exploratory analysis of efficacy according to hormone receptor (HR) status was performed. Results Forty-four patients were enrolled, and 43 patients were evaluable. ORR was 46.5 %. PFS and OS were 8.3 and 22.9 months, respectively. ORR was 45.5 % in patients with HR-positive tumors and 50 % in HR-negative cases. The most frequently observed grade 3/4 adverse events were neutropenia (27.9 %), leukopenia (11.6 %), hand-foot syndrome (HFS, 9.3 %) and fatigue (7.0 %). There were no discontinuations due to HFS. Conclusions Monthly XP was an effective and well-tolerated regimen for the first- or second-line treatment for MBC.