Preliminary trial results show promising results for Astra Zeneca's new breast cancer drug, fulvestrant (Faslodex),
the company says. Results from two phase III trials comparing
fulvestrant 250mg once monthly intramuscular injection with oral anastrozole (Arimidex) 1mg daily were presented by one of the trial authors, Professor John Robertson (City hospital, Newcastle), at the 23rd San Antonio cancer symposium on December 6.
Trial participants were postmenopausal women with advanced breast cancer that had progressed or recurred on prior hormonal therapy. Astra Zeneca report that in one study, the median duration of response was 19.3 months for fulvestrant and 10.5 months for anastrazole. In the other, the duration of response was similar for both drugs. The treatments were well tolerated in both studies.
The company says that fulvestrant is the first of a new class of drugs termed the "estrogen receptor downregulators". It downregulates estrogen receptors within tumour cells so that estrogen no longer has a binding target and tumour growth is minimised.