An Open-Label, Multinational, Multicenter, Phase IIIb Study with Subcutaneous Administration of Trastuzumab in Patients with HER2-Positive Early Breast Cancer to Evaluate Patient Satisfaction

Objective: This study was designed to investigate treatment satisfaction in patients and Health Care Professionals (HCP) and to evaluate the safety and tolerability of subcutaneous (SC) trastuzumab in patients with human epidermal growth factor receptor 2 (HER2)-positive early breast cancer (eBC). Materials and Methods: Two-hundred and twenty-three patients with eBC were screened, of whom 173 patients met the eligibility criteria and received at least one dose of SC trastuzumab. The primary efficacy endpoint was to assess patient satisfaction via a questionnaire. Results: The majority of patients (n = 166, 97.6%) reported satisfaction with the SC route. Patients and HCPs stated that SC trastuzumab was easy to use (93.5% and 62.5%, respectively) compared to the intravenous (IV) route and all HCPs (n = 16) expressed satisfaction with the SC route. Progression, disease recurrence or death was reported in 24 patients (13.8%) by two years of follow up. Four-year disease-free survival (DFS) and overall survival (OS) rates were 84.2% (±3.1) and 90.5% (±4.7), respectively. A total of 1299 adverse events (AEs) were recorded over 4-years follow-up, nearly 97% of which were judged non-serious. The most common AEs were arthralgia (n = 54, 4.2%), flu-like symptoms (n = 41, 3.2%) and nausea (n = 39, 3.0%). Fifty-four cardiac events, including left ventricular dysfunction, left ventricular failure and cardiotoxicity, were reported. Ejection fraction (EF) decrease [median decrease 3.5% (0.12-19.0)] was reported in 5.4% of cases. SC trastuzumab treatment was interrupted due to decreased EF in two cases. Conclusion: SC trastuzumab was widely acceptable to both patients and HCPs. The safety and tolerability of SC trastuzumab was consistent with the known safety profile of SC and IV administration.