The median progression-free survival for patients taking exemestane was 10.9 months compared with 6.7 months for those taking tamoxifen. Complete and partial response rates were also higher in the exemestane arm with 7.4% responding completely and 36.8% partially, compared to 2.6% of tamoxifen patients completely responding and 26.6% partially responding.
Dr Robert Paridaens will tell delegates at the 4th European Breast Cancer Conference today (Thursday 18 March) that the drug would be a good choice for first line treatment in hormone responsive metastatic breast cancer and that its safety profile meant it was also an attractive proposition for use as an adjuvant drug or to prevent breast cancer in high risk women. In Europe, it is currently licensed for use only in metastatic breast cancer that has recurred after, or during, tamoxifen treatment.
The majority of breast cancers in postmenopausal women rely on female hormones to grow. Exemestane is a steroidal aromatase inhibitor (SAI); it permanently inactivates aromatase, the enzyme that converts androgens into oestrogens in postmenopausal women. So, the effect of the drug is to deprive breast cancer cells of oestrogen.
Dr Paridaens, a medical oncologist at the University Hospital Gasthuisberg in Leuven, Belgium, said the trial was initiated as a phase II with the possibility of extending to phase III if results were promising. Phase III has involved 382 patients from 81 centres in 25 countries. It was an 'open label' study i.e. both doctors and patient knew which drug was being administered after patients were randomised to the tamoxifen or exemestane arm. The primary objective was to identify whether exemestane would produce an increas
Contact: Margaret Willson
Federation of European Cancer Societies