Aromasin prolongs breast cancer survival

New data supporting Pfizer's steroidal aromatase inhibitor Aromasin (exemestane) have been presented at the 4th European Breast Cancer Conference by Robert Paridaens of Universitair Ziekenhuis Gasthuisberg, Leuven, Belgium. First results of the randomized EORTC 10951 Phase III trial comparing exemestane 25mg/day with tamoxifen 20mg/day as first-line hormonal therapy in metastatic breast cancer show exemestane significantly extends the time interval before progression of disease.

These results follow publication of the major Intergroup Exemestane 031 Study this month in the New England Journal of Medicine. The IES 031 study showed patients who switched to exemestane after two-three years of adjuvant tamoxifen saw a significant improval in disease-free survival and a reduction in the incidence of contralateral breast cancer compared to patients remaining on standard tamoxifen treatment for five years.

In the new study, median time to progression was 9.95 months for the exemestane-treated group compared to 5.72 months for those on tamoxifen. Prof Paridaens noted: "the confidence intervals didn't overlap so this mean gain of four months survival free of disease progression is very significant." At six months, more than two-thirds of patients (67%) on exemestane had survived without disease progression compared with only 49% of the tamoxifen arm. At one year, the figures were 42% versus 31%. There were too few deaths to draw conclusions on overall survival at this stage, he said. Mature data would be available by mid-2004.