A phase II study of trastuzumab and capecitabine for patients with HER2-overexpressing metastatic breast cancer: Japan Breast Cancer Research Network (JBCRN) 00 Trial.

PURPOSE

To determine the response rate and toxicity profile of trastuzumab and capecitabine in women with HER2-overexpressing advanced breast cancer.

PATIENTS AND METHODS

A total of 59 patients from 6 participating centers in Japan entered onto the study of trastuzumab and capecitabine. Eighty six percent of women had received prior chemotherapy as part of adjuvant (21.4%) or metastatic treatment (48.2%), or both (16.1%), including substantial portions of patients who had previously received either CMF (7.1%), anthracyclines (28.6%), taxanes (25.0%), or both types (25.0%) of chemotherapy.

RESULTS

Responses were observed in 28 of 56 patients (overall response rate, 50%). The response rate was 65.0% in patients treated with trastuzumab and capecitabine as first-line therapy for metastatic disease, and 62.5% among HER2 +3 positive patients, while high response rates were also seen in women treated with second- or third-line therapy. Patients receiving trastuzumab and capecitabine as first-line therapy had a longer TTP than did patients receiving this treatment as second- or third-line therapy (median TTP, 280 vs. 130 days, P < 0.05). Further, patients receiving trastuzumab and capecitabine as first-line therapy had longer OS than did patients receiving this treatment as second- or third-line therapy (median OS, 780 days vs. 480 weeks, P < 0.05). The treatment-related adverse events were hand-foot syndrome (30.4%), nausea (25%), diarrhea (10.7%), stomatitis (10.7%), fatigue (7.1%), and vomiting (5.4%). However, the majority were Grade 1-2 adverse events and only six patients experienced Grade 3 adverse events. Further Grade 1 cardiac toxicity was observed in one patient, while there were no cases of alopecia and treatment-related death.

CONCLUSION

Trastuzumab in combination with capecitabine is highly active in women with HER2-overexpressing metastatic breast cancer and is well tolerated.