Source: Urology  |  Posted 11 years ago

SAN ANTONIO, TX -- December 11, 2000 -- AstraZeneca welcomes data from an independent comparative study presented at the San Antonio Breast Cancer Symposium, held in San Antonio, Texas. It identifies that Arimidex (anastrozole) provides a significant survival advantage over tamoxifen in postmenopausal women with hormone-sensitive advanced breast cancer.

These results also mirror the results from previous studies showing a significant advantage of Arimidex over tamoxifen in time to progression (TTP) in this group of patients.

Professor Alfredo Milla-Santos, of the Nuestra Sra.del Pilar Hospital, Barcelona, lead investigator, who presented the results today, says, "Our prospective randomised trial involved 238 patients with hormone-sensitive advanced breast cancer, who had not received previous adjuvant hormonal therapy. At data cut-off, only 61 percent of the patients had died in the Arimidex group compared to 92 percent in the tamoxifen group. Arimidex patients were 37 percent less likely to die than those receiving tamoxifen (HR=0.63 95 percent CI 0.51 - 0.89, p<0.05).

These results are especially significant because none of these patients had received previous adjuvant hormonal therapy and would not have been sensitised by prior endocrine treatments." Both treatments were reported to be well tolerated, as has been seen in other first line trials comparing Arimidex and tamoxifen.

Dr. Mark Steinberg, AstraZeneca Global Physician for Arimidex, says, "Survival is the most important endpoint in comparing treatments for cancer, and any gain in survival is important for the patient. The results of this independent comparative study are extremely encouraging since they show, in addition to a survival benefit, a doubling of TTP with Arimidex compared to tamoxifen in this group of patients. This reflects the combined results seen from similar recently published comparative studies involving Arimidex, conducted across North America and Europe involving 1,021 patients. The work of Professor Milla-Santos is exciting as this is the first randomised evidence to show an aromatase inhibitor to have a significant survival advantage over tamoxifen."

Arimidex was the first aromatase inhibitor to demonstrate superiority over tamoxifen. Across these recent studies, the advantage in TTP with Arimidex correlates with the percentage of hormone-sensitive patients receiving treatment. In the current independent study where all patients were hormone-sensitive, median TTP for Arimidex and tamoxifen was 10.6 months and 5.3 months respectively - a similar magnitude to the North American Study, where 89 percent patients were hormone-sensitive and TTP was 11.1 and 5.6 months for Arimidex and tamoxifen respectively. This is the largest difference in TTP ever seen between an aromatase inhibitor and tamoxifen.

These results may also translate into advantages for Arimidex in the adjuvant setting. Arimidex is the first aromatase inhibitor to be investigated for its potential role in early breast cancer, which will be revealed next year when results from the ATAC (Arimidex, Tamoxifen, Alone or in Combination) study are available, the largest adjuvant breast cancer study ever conducted.

Arimidex is a trademark, the property of the AstraZeneca group of companies.

In this study, hormone-sensitive refers to ER+ve and/or PR+ve. Patients were randomised to receive either anastrozole (n= 121) or tamoxifen (n=117). Primary end points were response rates, toxicity profile analysis, median TTP and overall survival. Overall response was 34 percent for Arimidex and 27 percent for tamoxifen.

The North American and European studies are two randomized multicentre trials, identical in design and objectives, comparing the efficacy and tolerability of tamoxifen and anastrozole as first-line endocrine therapy for postmenopausal women with advanced breast cancer. Both trials were designed to stand-alone but also allow for combined analysis. Both studies are reported in the Journal of Clinical Oncology (Nov 2000, 18 (22) 3748-3767). The combined results from both studies also identify that Arimidex is statistically significantly superior to tamoxifen with respect to TTP, in patients who have hormone-sensitive tumours. A paper reporting the combined analysis of both trials is currently under peer review by Cancer.

Arimidex is a potent, highly selective, non-steroidal aromatase inhibitor that exerts a therapeutic effect by inhibiting a key step in the production of oestrogen: Arimidex inhibits the conversion of androgens to oestrogens by the enzyme aromatase. In this way, the drug suppresses the levels of oestrogen circulating in the blood to non-detectable levels in postmenopausal women.

Related Links: [Arimidex (anastrozole)] and [AstraZeneca].