A phase II study of metronomic paclitaxel/cyclophosphamide/capecitabine followed by 5-fluorouracil/epirubicin/cyclophosphamide as preoperative chemotherapy for triple-negative or low hormone receptor expressing/HER2-negative primary breast cancer

Better treatments for triple-negative breast cancer (TNBC) are needed. To address this need, we studied the effects of preoperative metronomic paclitaxel/cyclophosphamide/capecitabine (mPCX) followed by 5-fluorouracil (FU)/epirubicin/cyclophosphamide (FEC) as preoperative chemotherapy in TNBC patients. Forty primary TNBC patients received four cycles of metronomic paclitaxel (80 mg/m(2) on Days 1, 8, and 15), cyclophosphamide (50 mg/body daily), and capecitabine (1,200 mg/m(2) daily), followed by four cycles of 5-FU (500 mg/m(2)), epirubicin (100 mg/m(2)), and cyclophosphamide (500 mg/m(2)) every 3 weeks. The primary end point was the pathological complete response (pCR) rate. Forty patients formed the intent-to-treat population. The median dose intensities of paclitaxel, cyclophosphamide, and capecitabine were 89.7, 92.1, and 89.8 %, respectively. Five patients discontinued mPCX and two discontinued FEC, primarily because of adverse events, resulting in a per-protocol population (PPS) of 33 patients. The pCR (ypT0/Tis ypN0) rate was 47.5 % (19/40) in the intent-to-treat population and 54.5 % (18/33) in the PPS. The clinical response rates were 36/40 (90.0 %) and 31/33 (93.9 %) in the intent-to-treat and PPS, respectively. The breast conservation rate was 72.7 % (24/33), and 5/13 patients underwent partial resection instead of pre-planned total mastectomy. Grade 3-4 adverse events included neutropenia (35 %), leukopenia (25 %), and hand-foot syndrome (8 %). Metronomic PCX followed by FEC chemotherapy was associated with a high pCR rate and low toxicity in TNBC patients. Further studies of this regimen in larger numbers of patients are warranted.