Phase II trial of weekly docetaxel, vinorelbine, and trastuzumab in the first-line treatment of patients with HER2-positive metastatic breast cancer.

BACKGROUND

The combinations of trastuzumab/docetaxel and trastuzumab/vinorelbine are highly active in the treatment of patients with HER2-positive metastatic breast cancer (MBC). We investigated the feasibility and safety of a 3-drug combination of trastuzumab, docetaxel, and vinorelbine as first-line therapy in this patient group.

PATIENTS AND METHODS

Sixty patients with previously untreated, measurable HER2-positive MBC (immunohistochemistry 3+ and/or fluorescence in situ hybridization positive) were treated with docetaxel 30 mg/m2 intravenously (I.V.) and vinorelbine 25 mg/m2 I.V. on days 1 and 8 of each 3-week cycle. Trastuzumab was given weekly (4-mg/kg loading dose followed by 2 mg/kg/week). Patients were evaluated after 6 weeks; responders/stable patients continued treatment until progression.

RESULTS

Patients received a median of 11 treatment cycles (range, 1-22 cycles). Forty-one of 60 patients (68%) had major responses (16 complete responses [27%], 25 partial responses [42%]). An additional 13 patients (22%) had stable disease for > or = 6 months. After a median follow-up of 58 months, median progression-free survival was 12 months (95% CI, 9.1-16.3 months), and the median overall survival was 40.8 months (95% CI, 25-not reached). Neutropenia (72% grade 4) was the most common hematologic toxicity; 8 patients were hospitalized for febrile neutropenia. A total of 67% of patients required dose modifications for neutropenia during cycles 1 or 2. Other grade 3/4 toxicities included fatigue (12%), hyperglycemia (7%), and myalgias (7%). There were no treatment-related deaths.

CONCLUSION

The combination of trastuzumab, docetaxel, and vinorelbine is highly active as first-line treatment for patients with HER2-positive MBC. However, this regimen offers no obvious advantages over other less myelosuppressive trastuzumab-containing regimens, and its routine use is not supported by the study.