New drug prevention status brings hope in fight against breast cancer

The Medicines and Healthcare products Regulatory Agency (MHRA) has granted a new indication for an NHS drug already used in the treatment of breast cancer in post-menopausal women that could benefit thousands more at moderate or high risk of developing the disease.

Anastrozole, which has been used off-label for prevention purposes, has been shown in trials to reduce the incidence of the disease in post-menopausal women at increased risk of the disease by almost 50%. Evidence was based on the IBIS-II study*, an international, randomised double-blind, placebo-controlled trial, which showed fewer women developed breast cancer in the anastrozole group compared to the placebo group.    

Breast cancer is the most common type of cancer in the UK. Most women diagnosed with breast cancer are over the age of 50, but younger women can also get breast cancer. Around 1 in 7 women will be diagnosed with breast cancer in their lifetime.

The drug was first recommended as a preventive option by the National Institute for Health and Care Excellence in 2017, however, with the treatment being unlicensed in this use, uptake has remained low.

Efforts by the Medicines Repurposing Programme led by NHS England, has now resulted in the new indication for the drug as a preventive option for women at increased risk, including those with a significant family history of the disease. As an aromatase inhibitor, anastrozole works by cutting down the amount of oestrogen that a patient’s body makes by blocking an enzyme called ‘aromatase’. The treatment is based on taking a 1mg tablet, once a day for 5 years.

Around 289,000 women could be eligible for the drug and 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 £15 million in treatment costs.

NHS chief executive, Amanda Pritchard, 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.

“Allowing more women to live healthier lives, free of breast cancer is truly remarkable and we hope that licensing anastrozole for a new use today represents the first step to ensuring this risk-reducing option can be accessed by all who could benefit from it.

“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.”

Set up in 2021, The Medicines Repurposing Programme, hosted by NHS England and supported by DHSC, the MHRA, NICE and the NIHR, builds on the innovation in medicines repurposing seen during the COVID-19 pandemic, which saw tocilizumab, an arthritis drug, and dexamethasone, a widely available steroid, repurposed as treatments for COVID-19.

The licensing work was undertaken by Accord Healthcare on a not-for-profit basis, after Accord Healthcare was selected through an open competitive process. The Medicines Repurposing Programme will now work with the MHRA and the British Generic Manufacturers Association to ensure other companies that make anastrozole adopt the new licensed indication.

Health Minister, Will Quince, said: “Breast cancer is the most common cancer in the UK so I’m delighted that another effective drug to help to prevent this cruel disease has now been approved. We’ve already seen the positive effect Anastrozole can have in treating the disease when it has been detected in post-menopausal women and now we can use it to stop it developing at all in some women.

“This is a great example of NHS England’s innovative Medicines Repurposing Programme supporting the development of new ways for NHS patients to benefit from existing treatments.”

Dame June Raine, Chief Executive of the MHRA, said: “This innovative Programme is essential to support and advance research into medicines that might be repurposed, increase access to life-saving medicines and ultimately improve patients’ lives. The MHRA welcomes applications for repurposed medicines and encourages early dialogue from companies or developers considering this.”

Baroness Delyth Morgan, chief executive at Breast Cancer Now, said: “The extension of anastrozole’s licence to cover it being used as a risk-reducing treatment is a major step forward that will enable more eligible women with a significant family history of breast cancer, to reduce their chance of developing the disease.

“For the past decade, Breast Cancer Now has been tirelessly campaigning with clinicians, researchers and patients for drugs that are found to be effective and safe in new uses to reach people who could benefit and we were thrilled when NHS England set up the Medicines Repurposing Programme. Anastrozole was the first drug to be supported by the programme and this paves the way for improving access to risk-reducing drugs. We look forward to continuing our work with NHS England to further improve access to these drugs for everyone eligible.”

Jonathan Wilson, Senior Vice President at Accord Healthcare said: “We believe in the untapped potential of existing medicines to serve broader healthcare needs. Our work with the Medicines Repurposing Programme isn’t just about innovation; it’s about creating real, measurable outcomes for patients.

“By obtaining this licence variation in partnership with the Programme, we’ve not only expanded treatment options but also provided renewed hope for thousands of individuals. It’s a profound step forward, validating our commitment to collaboratively advancing healthcare with quality, safety and efficacy at the forefront.”

*Cuzick, J., et al. (2013). Anastrozole for prevention of breast cancer in high-risk postmenopausal women (IBIS-II): an international, double-blind, randomised placebo-controlled trial. The Lancet, doi:10.1016/S0140-6736(13)62292-8.

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