Paclitaxel and trastuzumab as maintenance therapy in patients with HER2-positive metastatic breast cancer who underwent high-dose chemotherapy and autologous hematopoietic stem cell transplantation

We examined the feasibility and safety of using paclitaxel and trastuzumab as maintenance therapy after high-dose chemotherapy (HDC) with autologous hematopoietic stem cell transplantation (AHST) for patients with HER2-positive metastatic breast cancer. Ten patients (9 women and 1 man) were enrolled in the study. The median age was 46.5 years (range, 27-65 years). The median follow-up time was 1003 days (range, 216-2526 days). All patients had metastatic disease, but 2 had only bone metastasis. One patient had complete response, 6 had partial response and 3 had stable disease to the standard-dose chemotherapy prior to transplantation. The conditioning regimen consisted of cyclophosphamide, carmustine, and thiotepa. After AHST, patients received weekly paclitaxel for 12 doses and trastuzumab every 3 weeks for 1 year as maintenance therapy. All patients experienced successful engraftment. The only grade 4 toxic effects observed were leukopenia and thrombocytopenia. The most common grade 3 toxic effect was neutropenic fever. No treatment-related deaths were observed. The median progression-free survival time was 441 days, and the median overall survival time was 955 days. Two patients died in accidents while their disease remained in remission. Five patients died with disease progression. At the time of this report, 3 patients are alive with stable disease, 1 of whom has remained free of disease progression for 2526 days since transplantation. Our findings indicate that paclitaxel plus trastuzumab as maintenance therapy after HDC with AHST for patients with HER2-positive metastatic breast cancer not only is feasible and safe but also results in survival outcomes similar to historical results.