Background: In order to determine the feasibility of substituting pegylated liposomal doxorubicin (PLD) for doxorubicin in combination with cyclophosphamide and trastuzumab as adjuvant therapy, we conducted a phase II study of the combination as first-line therapy in human epidermal growth factor receptor 2 (HER2) overexpressing metastatic breast cancer (MBC).
Methods: PLD 50 mg/m(2) and cyclophosphamide 600 mg/m(2) were administered every 4 weeks for six cycles; trastuzumab (4 mg/kg loading dose, then 2 mg/kg) was administered weekly for 24 weeks. The primary end point was objective response rate (ORR), and the secondary end points included time to progression (TTP), overall survival (OS), and safety.
Results: Among the 48 evaluable patients, ORR was 68.8% [95% confidence interval (CI) 55.69% to 81.91%], with 6 patients (12.5%) achieving a complete response and 27 (56.2%) a partial response. The median TTP was 12 months (95% CI 9-15.1 months), and the median OS was 34.2 months (95% CI 27.2-41.2 months). Febrile neutropenia was seen in three patients, grade 3 hand-foot syndrome in 29.2% of patients, and grade 3-4 mucositis in 22.9% of patients. Symptomatic congestive heart failure was not observed, and 16.7% of patients experienced grade 2 asymptomatic left ventricular systolic dysfunction.
Conclusion: The combination of PLD-cyclophosphamide-concurrent trastuzumab is a feasible, safe, and effective first-line regimen for HER2-overexpressing MBC.