AstraZeneca has already begun to provide the FDA with data and plans to complete the rolling submission of the supplementary new drug application (sNDA) for Arimidex by the end of February 2002. The FDA grants fast-track status for products that may offer significant improvements in how a disease is treated.

“The decision by the FDA is very encouraging news for women with early stage breast cancer and, we believe, reflects the considerable potential for Arimidex in this area. We welcome this decision by the FDA, and hope that a rapid licence review process will help bring the proven benefits, both in terms of efficacy and safety, of this product to many women in the US, newly diagnosed with early stage breast cancer,” said Dr George Blackledge, Medical Vice-president, Oncology, AstraZeneca.

Arimidex sales in 2000 were $156 million, a 19 per cent increase over the previous year. AstraZeneca’s Nolvadex® (tamoxifen) accounted for $576 million in sales the same year. The early breast cancer market could be worth approximately $2 billion.

After an average of 33 month’s follow-up, Arimidex monotherapy was found to be significantly more effective in preventing relapse than tamoxifen, with a 17 per cent reduction in risk of breast cancer recurring with Arimidex treatment compared with tamoxifen.

Arimidex was also found to have many important tolerability advantages over tamoxifen. Arimidex was associated with significantly fewer reports of endometrial cancer when compared with tamoxifen. This finding was supported by a significantly lower incidence of vaginal bleeding and vaginal discharge among Arimidex-treated patients compared to those taking tamoxifen.

Another known risk associated with tamoxifen is thromboembolic events. In the ATAC trial, both the overall incidence of thromboembolic events and that of deep vein thromboses were significantly reduced in the Arimidex group. Important from the patient’s perspective, the incidence of hot flushes and weight gain were also significantly reduced. However, as expected, women taking tamoxifen did have a lower risk of experiencing musculo-skeletal disorders or the types of fractures common in this age group compared with those taking Arimidex.