A Peter Mac-supported international clinical trial has shown women treated for early-stage breast cancer can dramatically reduce their risk of cancer returning by taking medication.

Results of the OlympiA clinical trial were presented at the plenary session of the 2021 American Society of Clinical Oncology (ASCO) Annual Meeting over the weekend.

The Phase III clinical trial showed that taking olaparib tablets twice daily for a year reduced breast cancer recurrence by 42%.

Women in the trial all had a BRCA1 or BRCA2 gene mutation placing them at increased lifetime risk for breast cancer, and they had received chemotherapy for breast cancer detected at an early stage.

 In Australia the trial was conducted by Breast Cancer Trials, with major support from Peter MacCallum Cancer Centre.

Professor Kelly-Anne Phillips - a Peter Mac oncologist and Breast Cancer Trials Study Chair of the OlympiA clinical trial - said the results provide a new treatment option for patients with early-stage breast cancer.

“One of the biggest fears that patients have is that their breast cancer will come back,” Prof Phillips said.

 “The OlympiA clinical trial has identified a new treatment for patients with early-stage breast cancer - that have a genetic mutation in the BRCA1 or BRCA2 genes - that may help prevent their breast cancer returning and cancer spreading, after their initial treatment has been completed.”

Professor Kelly-Anne Phillips
Professor Kelly-Anne Phillips

Approximately 5% of all breast cancer patients have a BRCA1 or BRCA2 gene mutation, which equates to roughly 1,000 women diagnosed with breast cancer in Australia each year.

These women are typically diagnosed with breast cancer at a younger age and often have a particularly aggressive form of breast cancer.

The OlympiA clinical trial was coordinated internationally by the Breast International Group and recruited 1,836 patients worldwide, including 60 women from Australia.

OlympiA found giving olaparib to women after they completed chemotherapy increased the chance that they will remain free of invasive or metastatic cancer. The trial tested the efficacy and safety of olaparib tablets versus placebo as adjuvant treatment.

Olaparib exploits an inherent defect in DNA repair that is present in the cancers of people with a BRCA1 or BRCA2 mutation, ensuring that cancer cells are more likely to die.

 “Our study findings are a significant step forward in the precision treatment of breast cancer and provides a new treatment option,” Professor Phillips said.

“The findings also mean that genetic testing for BRCA1 and BRCA2 will likely become more routine for all women with newly diagnosed breast cancer.

“This will have the downstream effect of helping us to identify their relatives who also have the gene abnormality and who can therefore undertake evidence-based treatments that can prevent them getting cancer.”

Professor Phillips thanked the women who took part in the trial and made this treatment advance possible, and the many clinicians and study staff across Australia who contributed to these landmark results.

The OlympiA results were also published in the New England Journal of Medicine – Read them in full here: https://www.nejm.org/doi/full/10.1056/NEJMoa2105215

For more information about Breast Cancer Trials, visit: www.breastcancertrials.org.au