Metronomic oral chemotherapy with cyclophosphamide plus capecitabine combined with trastuzumab (HEX) as first line therapy of HER-2 positive advanced breast cancer: A phase II trial of the Gruppo Oncologico Italia Meridionale (GOIM)

BACKGROUND: The combination of chemotherapy plus anti HER-2 agents is the mainstay of HER-2 positive advanced breast cancer (ABC) therapy. We conducted a phase II trial testing activity and safety of trastuzumab and metronomic capecitabine/cyclophosphamide (HEX) as first-line therapy in HER-2 positive ABC. Methods. Patients at first relapse or with synchronous metastasis were treated with trastuzumab (4 mg/kg, biweekly) plus oral capecitabine (1500 mg/daily) and cyclophosphamide (50 mg/daily). Primary endpoint was objective response rate (ORR), secondary endpoints progression-free survival (PFS), clinical benefit rate (CBR; PR + CR + SD for ≥ 24 weeks) and tolerability. Optimal two-stage design was applied. RESULTS: Sixty patients with measurable ABC, tumors scored as +3 for HER-2 or FISH +, untreated for advanced disease were enrolled. Median age was 62.5 years, visceral metastases were present in most patients (57.9%). Median number of cycles was 16 (range 1-98). ORR was 56.7% (95% CI, 44.1-68.4%), with 5 CR (8.3%) and 29 PR (48.3%). Fifteen patients had SD (25%). The CBR was 78.2%. Nine progressions were observed (15%). Median PFS was 11 months. One year PFS was 47.7%. Median OS was 45.9 months. Worst toxicities were grade 3 hand-foot syndrome in 2 pts (3.3%), grade 3 anaemia in 2 pts (3.3%), grade 2 nausea in 2 pts (3.3%) and grade 3-4 diarrhea in 2 pts (3.3%). Cardiac toxicity grade 1 was reported in 1 pt. CONCLUSIONS: Combination of trastuzumab and metronomic oral chemotherapy has clinical activity. The tolerability was excellent and allowed the prolonged delivery of treatment.