Medicines regulator approves anastrozole for prevention of breast cancer in post-menopausal women

NHS England says around 289,000 women at moderate or high risk of breast cancer could benefit from anastrozole.
Older woman having a mammography scan at hospital

The Medicines and Healthcare products Regulatory Agency (MHRA) has authorised the use of anastrozole as a preventative option for post-menopausal women at moderate or high risk of breast cancer.

In a statement published on 6 November 2023, the MHRA announced the approval of the five-year treatment, following results from the IBIS-II’ trial which showed that anastrozole reduced the risk of breast cancer in post-menopausal women by almost 50%.

Anastrozole (Arimidex; AstraZeneca UK) is an aromatase inhibitor, which is administered as a tablet and works by reducing a patient’s oestrogen production.

The drug was first recommended in 2017 as a preventative option for this patient group by the National Institute for Health and Care Excellence, but uptake had remained low because the treatment was previously unlicensed for this use. It was previously only indicated for the treatment of oestrogen-receptor-positive early invasive breast cancer in post-menopausal women.

Breast cancer is the most common type of cancer in the UK, affecting around 1 in 7 women — most commonly women aged over 50 years. Breast cancer is the fourth most common cause of cancer death in the UK, with around 11,500 deaths from breast cancer in the UK every year.

In a news story published on 7 November 2023, NHS England said that around 289,000 women at moderate or high risk of breast cancer could benefit from anastrozole.

“While not all will choose to take it, it is estimated that if 25% do, around 2,000 cases of breast cancer could potentially be prevented in England, while saving the NHS around £15m in treatment costs,” NHS England said.

Commenting on the approval, Nuttan Tanna, pharmacist consultant in women’s health and osteoporosis at London North West University Healthcare NHS Trust, said: “I think it’s a great step forward.

“Our breast units did prescribe anastrozole off-licence in some cases with strong family history of breast cancer. This would be if the woman could not tolerate tamoxifen.

“With licensing, patients now have a choice of medicines for prevention,” she said.

The MHRA’s decision to license anastrozole for a new indication was made as part of the Medicines Repurposing programme, which was launched by NHS England in March 2021 to identify and facilitate new use of medicines that are outside of their existing licenses.

In September 2023, NHS England told The Pharmaceutical Journal that there were four medicines currently supported by the programme: anastrozole to prevent breast cancer; metformin for tuberous sclerosis complex; direct oral anticoagulants to prevent blood clots in people with lung cancer; and candesartan to prevent migraine.

Commenting on the approval, Amanda Pritchard, chief executive of the NHS, said: “It’s fantastic that this vital risk-reducing option could now help thousands of women and their families avoid the distress of a breast cancer diagnosis.

“This is the first drug to be repurposed through a world-leading new programme to help us realise the full potential of existing medicines in new uses to save and improve more lives on the NHS.

“Thanks to this initiative, we hope that greater access to anastrozole could enable more women to take risk-reducing steps if they’d like to, helping them live without fear of breast cancer.”

Last updated
The Pharmaceutical Journal, PJ, November 2023, Vol 311, No 7979;311(7979)::DOI:10.1211/PJ.2023.1.200128

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