Results from a randomized phase II clinical study in the first-line treatment of advanced breast cancer in postmenopausal women suggest Aromasin (exemestane tablets) has a higher response rate when compared to tamoxifen. Response rate is a measurement of how effective the treatments are in shrinking the tumor.
Additionally, the study suggests Aromasin has no adverse effect on blood lipid levels, an important consideration for postmenopausal women who, by virtue of their age, are at an increased risk for developing cardiovascular disease. The data was presented today at the American Society for Clinical Oncology (ASCO) annual meeting in San Francisco.
“These findings are very promising. Exemestane demonstrated high activity as an investigational agent in the first-line treatment of breast cancer,” explained Caroline Lohrisch, MD, Research Fellow, Investigational Drug Branch for Breast Cancer, European Organization for Research and Treatment of Cancer (EORTC), the organization that conducted the clinical trial. “Given the strength of these findings we have expanded this study into a Phase III trial, which will allow formal comparison of tamoxifen and exemestane.”
The study randomized postmenopausal women with advanced breast cancer to either Aromasin (25 mg/day) or tamoxifen (20 mg/day). Of the 122 randomized patients, data are available on 109 for tumor response and 117 for tolerability. The results indicate that patients treated with Aromasin had three times the response rate (complete plus partial responses) in shrinking tumors (44.6 percent vs. 14.3 percent) relative to tamoxifen-treated patients. All responses have been independently reviewed by a third-party.
A sub-study of this trial examined the effect of Aromasin and tamoxifen on triglycerides, HDL and total cholesterol by measuring serum levels of the 122 women (62 Aromasin, 60 tamoxifen) before and during therapy. In general, after 24 weeks, the majority of patients with normal baseline triglyceride or HDL levels experienced no clinically relevant changes in these values. After 24 weeks, women with normal triglyceride levels at baseline (Aromasin 33, tamoxifen 27), experienced a decrease of 20 percent or greater in triglyceride levels in 36 percent and 15 percent patients treated with Aromasin and tamoxifen, respectively.
Dr. Lohrisch continues, “Early results of this sub-study, of a limited number of patients, suggest that exemestane has no negative effect on triglycerides and HDL cholesterol, which is the good cholesterol.