Clinical outcomes of patients of different races in a phase IV community-based trial of first-line trastuzumab plus a taxane in HER2+ metastatic breast cancer (MBC)

Abstract

751 Background: Trastuzumab (Herceptin, H) is a humanized monoclonal antibody which showed a significant survival benefit in a randomized trial comparing chemotherapy plus H vs. chemotherapy alone in first-line treatment of HER2+ MBC. Race has been associated with differences in clinical outcome in breast cancer in numerous studies, and non-White patients (pts) are typically underrepresented in clinical trial populations. To investigate differences in outcomes for patients with HER2+ MBC, we performed an exploratory analysis to determine whether baseline characteristics or clinical outcomes differed by race in this large non-randomized, community-based, phase IV trial of first-line taxane/H therapy. Methods: Pts had previously untreated HER2+ MBC (prior hormonal therapy allowed), normal left ventricular ejection fraction (LVEF), and measurable or evaluable disease. All pts received H weekly with either paclitaxel or docetaxel at standard doses. Results: 466 pts have been enrolled: 364 White (78%), 61 African-American (13%), 41 Other (9%) (Hispanic, Asian/Pacific Islander, Native American). The distributions of selected baseline characteristics (age, median time since primary diagnosis, stage at initial diagnosis) were similar between the groups. See table for clinical outcomes. Non-White patients had a lower response rate to taxane/H therapy than did White patients. Conclusions: These exploratory analyses suggest that in this large, non-randomized phase IV community-based study of HER2+ MBC, patients obtained clinical benefit from taxane/H therapy regardless of race. Median survival has not yet been reached for African-American subjects. Cardiac evaluations (serial LVEF measurements) were similar for all groups. Author Disclosure Employment or Leadership Consultant or Advisory Role Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration Genentech Genentech