Clinical trial to prevent breast cancer in women starts in Australia

Today sees the official launch of a clinical trial being led in Australia by Breast Cancer Trials.

This is the first global clinical trial that aims to prevent breast cancer in women with the BRCA1 gene mutation.

It is estimated that in Australia today, about one in 400 women are at the highest risk of breast cancer because they carry a BRCA1 or BRCA2 gene mutation. These women have a 70 per cent risk of developing breast cancer over the course of their lifetime and a 40 per cent risk of developing ovarian cancer. For BRCA1, this equates to 15,000 Australian women who may be at high risk of developing breast cancer by the age of 80.

The clinical trial will test the effectiveness of using a drug called Denosumab to decrease or prevent the risk of developing breast cancer in women who carry a BRCA1 gene mutation. Denosumab is an antibody that neutralises a molecule called RANK ligand. Switching off RANK ligand with Denosumab has been shown in other research to strengthen bone function for people with weak bones (osteoporosis) and to improve outcomes for women whose breast cancer has spread to the bone.

Recent laboratory studies, led by Professor Jane Visvader and Professor Geoff Lindeman at the Walter and Eliza Hall Institute, suggest that switching off RANK ligand with Denosumab could also target the culprit cell that gives rise to breast cancer in women with the BRCA1 gene mutation. The BRCA1 gene mutation has been shown in the laboratory to result in a hyper-sensitive signalling pathway involving RANK ligand.

Denosumab may be able to switch this off.

Denosumab is approved in Australia for the treatment of osteoporosis in postmenopausal people and for the prevention of bone-related problems in adults with bone metastases due to cancer.

The BRCA-P prevention clinical trial has been fast-tracked from the laboratory because of the very positive pre-clinical data seen and because a Phase III clinical trial can provide the large numbers of participants needed to indicate efficacy in the shortest time frame. If the trial is successful, it will be the first treatment shown to prevent ER-negative breast cancer.The trial will recruit women with the BRCA1 gene mutation, who are aged 25 to 55, and are breast and ovarian cancer free. Breast cancers associated with BRCA1 and BRCA2 mutations tend to develop in younger women where the incidence becomes significant in their 30s or 40s and it accounts for 5% of breast cancers in Australia.

“These women have a 70 per cent life-time risk of developing breast cancer, with few prevention options available beyond bilateral mastectomy. This trial aims to determine whether we can safely and effectively prevent or delay breast cancer in this ‘high-risk’ group,” said Professor Lindeman.

“I’ve been conducting research in this area for 20 years. I also see women in my clinic with breast cancer who are BRCA1 gene mutation carriers, so I know firsthand how devastating this can be. I’m excited that this new research could stop cancers in their tracks – before they've developed.”

Many of those at this highest risk of breast cancer will not be aware they carry a breast cancer gene mutation until they are diagnosed with breast cancer themselves or a close family member is diagnosed. Each of them will have the potential to pass this inherited gene mutation to their children.

“The results of this clinical trial could see a landmark breakthrough in the prevention of breast cancer for people in our community who are the highest risk, with Australia at the forefront of this research,” said Professor Lindeman.

Throughout Australia, 14 sites will be open to patient recruitment together with seven other countries including Austria, Germany, Israel, Spain, the UK and the US.

Researchers aim to recruit 300 women to the trial in Australia over the next two years.

Breast Cancer Trials – www.breastcancertrials.org.au – has been conducting clinical trials research for more than 40 years and the results have improved the treatment of the disease which has saved millions of lives through research collaboration. The research program brings together about 800 researchers in 102 institutions throughout Australia and New Zealand. More than 15,700 women have participated in BCT clinical trials.