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/m² twice daily, days 1-21) plus paclitaxel (80 mg/m², 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.