Tamoxifen superior to arzoxifene for locally advanced or metastatic breast cancer

November 16, 2007

NEW YORK (Reuters Health) - Compared with arzoxifene, tamoxifen provides longer progression-free survival and time to treatment failure in women with locally advanced and metastatic breast cancer, according to a report in the November 1st Journal of Clinical Oncology.

In phase II studies, arzoxifene (a selective estrogen-receptor modulator (SERM) showed efficacy similar to or greater than that historically reported for tamoxifen in treating recurrent or metastatic breast cancer, the authors explain.

Dr. VijayaLaxmi Deshmane from Kidwai Memorial Institute of Oncology, Karnataka, Bangalore, India, and colleagues compared progression-free survival time between arzoxifene 20 mg daily and tamoxifen 20 mg daily in the treatment of women with locally advanced or metastatic breast cancer who had not received any prior systemic therapy or who relapsed more than 12 months after stopping adjuvant hormonal therapy.

At the planned interim analysis, all time-to-event outcomes favored tamoxifen over arzoxifene, the authors report. Based on this analysis, the trial was stopped.

Progression-free survival and time to treatment failure were significantly better with tamoxifen than with arzoxifene, the report indicates, but total response rate, clinical benefit response rate, duration of response, and overall survival did not differ significantly between the 2 treatments.

Treatment-related adverse events were similar for the 2 treatments, though nausea was reported more frequently in the arzoxifene group and vaginal discharge was reported more frequently in the tamoxifen group.

"These findings do not support the further development of arzoxifene as a superior treatment to tamoxifen in women with locally advanced or metastatic breast cancer," the authors conclude.