The UK’s National Institute of Health and Clinical Excellence (NICE) has agreed that drugs in the aromatase inhibitor class should be offered to post-menopausal women with early-stage breast cancer under the National Health Service.

Aromatase inhibitors - which include AstraZeneca’s Arimidex (anastrozole), Novartis’ Femara (letrozole) and Pfizer’s Aromasin (exemestane) – will be made available on the NHS for early-stage breast cancer patients alongside the anti-oestrogen tamoxifen, which has been a mainstay of treatment for decades.

The publication of the draft Final Appraisal Document by the UK’s cost-effectiveness watchdog means that around 23,000 women who are newly-diagnosed with early breast cancer and scheduled for surgery each year can now receive adjunctive aromatase inhibitor treatment as a matter of course.

Tamoxifen is currently prescribed for five years after surgery to post-menopausal women with oestrogen-receptor positive breast cancer in order to cut the risk of relapse.

The new NICE guidance says that Arimidex can be used in place of tamoxifen for this period, while Aromasin should be used for women wanting to switch drugs after taking tamoxifen for two to three years. Femara may be used for five years after surgery as well as after a five-year course of tamoxifen in order to provide extended adjuvant therapy.

The draft FAD could still be appealed, but is not expected to be challenged as the benefits of the aromatase inhibitors over tamoxifen have been demonstrated in a number of clinical trials.

NICE notes in its guidance that on the current evidence there is no evidence to conclude that one aromatase inhibitor is better than another clinically, although Novartis has decided to undertake a head-to-head trial of Femara versus Arimidex – called FACE - in the post-surgery setting.

Arimidex is AstraZeneca’s fifth-largest product and heads the aromatase inhibitor market, bringing in sales of $714 million in the first half of this year. Femara is following in second place with $320 million in revenues for the same period, although has been growing faster than AstraZeneca’s drug in recent quarters. Finally, Aromasin brought in $145 million.

Commenting on the news, Prof John Toy, medical director of Cancer Research UK, said: “The new guidelines now mean that all doctors on the NHS will be able to prescribe these important drugs to post-menopausal women with early stage breast cancer. Aromatase inhibitors form a key part of the new battery of treatments available for women with breast cancer.”