AstraZeneca's breast cancer treatment Arimidex has received UK approval for post-surgery use to help older women fight tumours.

Its extended approval means more women whose cancer is fuelled by the hormone oestrogen - about 75% of postmenopausal women - will be eligible to receive Arimidex.

"This is the moment we have been waiting for," said Rob Carpenter, consultant surgical oncologist at Bart in London.  

He said new data showed Arimidex helped patients stay disease free for longer than current gold standard tamoxifen, and that the new indication represented a significant advance in the fight against breast cancer.

"This news marks the beginning of a whole new era in breast cancer management," he said.

Arimidex (anastrozole) is the clear UK market leader in the aromatase inhibitor class of drugs, with the NHS spending over £34 million on the brand in England last year.

The two rival aromatase inhibitor drugs, Novartis' Femara (letrozole) and Pfizer's Aromasin (exemestane) trail far behind Arimidex, with sales of less than £5 million and £4 million respectively.

This mirrors the global picture, where Arimidex earned over $800 million last year while Femara sales were under $400 million.

Arimidex's grip on the aromatase inhibitor class is likely to be further strengthened with its new approval which was granted on the back of data from the largest ever breast cancer trial.

The data showed Arimidex reduced the chances of breast cancer returning after treatment by 26% more than the 50% rate for tamoxifen. The drug was also shown to reduce by 16% the chance of secondary cancers developing compared to the older drug.

Emma Pennery, nurse consultant at charity Breast Cancer Care said: "This is exciting news for the 33,000 postmenopausal women diagnosed with breast cancer every year in the UK. Every patient eligible for hormone therapy will now have the opportunity to benefit from this more effective treatment option."

She added that it was now crucial that women were fully informed and confident in discussing treatment options with their doctors to ensure they get the best treatment, and as early as possible.

AstraZeneca said it expects approvals in five other European countries - Germany, Italy, Portugal, Spain and Austria  - where tamoxifen is currently the standard treatment.

Novartis recently filed Femara for the same post-surgery indication as Arimidex in the UK and Europe, and has shown similar outcomes in large-scale trails compared to tamoxifen.

Aromatase inhibitors can only be used in women after the menopause or those whose cancer is hormone receptor-positive.

Related articles:

AstraZeneca remains strong despite setbacks

Tuesday , February 01, 2005

pharmafocus@wiley.co.uk