Around 75% of all postmenopausal cases of breast cancer are linked to estrogen. It is this patient population who will now be able to benefit from the use of Arimidex as an adjunctive therapy after undegoing surgery. Arimidex offers a 26% reduction in the risk of breast cancer coming back compared with tamoxifen, the ‘gold standard’ for breast cancer management for the last 30 years.
“This is the moment we have been waiting for,” said Mr Carpenter, consultant surgical oncologist at St Bartholomew’s Hospital, London. “It has recently been confirmed that Arimidex offers crucial advantages over tamoxifen, in terms of enabling patients to stay disease free for longer. However, it is only now, with the new indication that more postmenopausal women with breast cancer may benefit from this drug at the earliest opportunity after breast surgery. This news marks the beginning of a whole new era in breast cancer management.”
Unfortunately, although the treatment has proved significantly more effective than tamoxifen it is also far more expensive. Arimidex will cost the UK approximately $1,815 a year compared to tamoxifen which only costs $35 to $55. This will increase costs to the UK health services by tens of millions of pounds each year.
The approval was granted following the submission of data from the largest breast cancer trial ever conducted. The study demonstrates that Arimidex reduces the risk of breast cancer recurring by an additional 26% over and above the 50% reduction provided by tamoxifen. Moreover, it may prevent life-threatening secondary cancers outside the breast by an additional 16%.
In 2004, Arimidex’s worldwide sales increased by 48% to $811 million, of which $358 million were in Europe.
As the UK acts as a reference for other member states AstraZeneca expects the approval to lead to further approvals in five other European countries, namely Austria, Germany, Italy, Portugal and Spain.