Publication Year: 2000 Visited: 282

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Elevated Serum HER-2/neu Level Predicts Decreased Response to Hormone Therapy in Metastatic Breast Cancer. Allan Lipton, Suhail M Ali, Kim Leitzel, Vernon Chinchilli, Linda Engle, Larry Demers, Caroline Brady, Walter Carney, Gabriela B Cook, Deborah Cambetas, Jeffrey Allard, Penn State/Hershey Medical Ctr, Hershey, PA; VA Medical Ctr, Lebanon, PA; Novartis Pharmaceuticals Corp, East Hanover, NJ; Oncogene Science Diagnostics Inc, Cambridge, MA; Bayer Corp, Tarrytown, NY.

Serum HER-2/neu levels were measured in pretreatment sera from 566 metastatic breast cancer patients enrolled in two randomized second-line hormone therapy trials. Serum HER-2/neu levels were measured using an automated HER-2/neu assay (Bayer Immuno 1 for research use). A cutoff of 15 ng/ml (mean + 2SD) was derived from the sera of 211 healthy women. 168 / 566 patients (30%) had elevated serum HER-2/neu levels. Response rate, time to progression and survival with respect to elevated vs. normal serum HER-2/neu were analyzed. The response rate (CR+PR+Stable disease) was less in the HER-2/neu elevated patients (41/168)(24%) when compared to patients with normal serum HER-2/neu (176/398)(44%)(p<0.0001). For the responding patients (CR+PR+S), the duration of response was also significantly shorter for patients with elevated HER-2/neu (p<0.0001). In all patients, time to progression (TTP) (p<0.0001) and overall survival (OS) (p<0.0001) were also significantly shorter for patients with elevated serum HER-2/neu levels when compared to patients with normal levels. A multivariate model for response rate, TTP and OS was performed including serum HER-2/neu, age, race, disease-free interval, performance status, visceral vs. non-visceral metastasis, and ER/PR status as variables. After adjusting for the other variables, elevated serum HER-2/neu level remained a predictive factor for patient response, TTP and OS. In conclusion, patients with elevated serum HER-2/neu had significantly lower response rate, decreased time to progression, and shortened survival when treated with second-line hormone therapy.