Phase II trial of vinorelbine and trastuzumab in patients with HER2-positive metastatic breast cancer. A prospective, open label, non-controlled, multicenter phase II trial (to investigate efficacy and safety of this combination chemotherapy)

The purpose of this study was to evaluate the efficacy (progression free survival (PFS) and response rate) and safety of vinorelbine and trastuzumab combination chemotherapy in patients with HER2-overexpressing, metastatic breast cancer as a first line chemotherapy regimen. Patients with histologically confirmed, HER2-positive (immunohistochemistry (ICH) 3+, or 2+ and FISH+) metastatic breast cancer who had nor received prior vinorelbine or anti-HER2 therapy in the adjuvant setting, received at least eight weeks of vinorelbine i.v. (25 mg/g weekly) and trastuzumab (4 mg/kg on day 1 followed by 2 mg/kg weekly). Forty-one women from six participating centers were enrolled into the trial. The overall response rate, was 43.9% (18 of 41 patients), (CI 28-60.3%), 30% of patients were progression free after 1 year. Four patients reached complete remission, 14 partial remission and five had stable disease for at least 18 weeks. Six patients developed primary progression. 35 patients (85%) experienced progression after a median time of 235 days. Therapy was in general well-tolerated. There were two CTC grade 4 infusion syndromes and two patients experienced cardiotoxicity at least grade 2. This phase II trial of vinorelbine and trastuzumab demonstrated an effective and well-tolerated regimen with a favourable safety profile.