[Neoadjuvant Epirubicin-Cyclophosphamide Therapy followed by Nab-Paclitaxel in Patients with Operable Breast Cancer-A Single-Center Phase Ⅱ Trial].

Clinical studies have confirmed that nab-paclitaxel(nab-PTX)therapy is effective and safe in patients with metastatic breast cancer. Neoadjuvant chemotherapy(NAC) with nab-PTX has resulted in a pathological complete response (pCR) rate of 29% in all cases and 58% in HER2-positive cases. However, these data were obtained from an overseas study, and the effectiveness and safety of NAC with nab-PTX remain unclear in Japan. Thus, the present study was conducted to investigate these aspects. In patients with T1-3, N0-2, M0 breast cancer, 4 cycles of 260 mg/m2 nab-PTX were administered every 3 weeks after 4 cycles of EC therapy(100 mg/m2 of epirubicin and 600 mg/m2 of cyclophosphamide)as NAC. In HER2- positive patients, trastuzumab was used in combination with nab-PTX. Overall, 14 patients were registered between October 2014 and October 2018. One patient who had requested for another drug after providing informed consent was excluded, and the remaining 13 patients were analyzed. The primary endpoint was pCR rate. The median age of the subjects was 57 years, and the median tumor diameter was 35 mm. There were 7 cases of Stage Ⅱ disease and 6 cases of Stage Ⅲ disease. As for tumor subtype, there were 7 cases of Luminal-type, 2 cases of Luminal- HER2-type, 4 cases of HER2-type, and no triple negative-type tumors(the cut-off values for estrogen receptor [ER] and progesterone receptor were both 1%). The objective response rate to NAC was 77%(10/13 cases), and no PD was observed. The pCR rate was 54%(7/13 cases): 2 patients had Luminal-type tumors, 1 had a Luminal-HER2-type tumor, and 4 had HER2-type tumors. Predictive factors for pCR were ER negativity and HER2 positivity. Common adverse events of chemotherapy were hair loss, pain, malaise, anemia, dysgeusia, constipation, itchiness, and numbness, but their severity was modest, and they were manageable. This study suggests the efficacy and safety of nab-PTX after EC therapy in Japanese patients with operable breast cancer.