Results from a global clinical trial have shown a 32% reduction in breast cancer deaths in patients where the cancer had not spread beyond the breast or under the arm.

The OlympiA trial has revealed practice changing results, demonstrating a significant improvement in survival for patients with early breast cancer who carry BRCA1 or BRCA2 gene mutations.

The study, led in Australia by Professor Kelly-Anne Phillips, focused on the use of the targeted drug olaparib as additional therapy for patients with high-risk, early-stage breast cancer and BRCA1/2 gene mutations.

The trial included 1,836 participants with BRCA1 or BRCA2 mutations from around the world, including 60 women from Australia, and examined the effectiveness and safety of olaparib compared to a placebo. Patients received either olaparib or a placebo after undergoing chemotherapy, surgery and radiation therapy when needed.

Additionally, hormone therapy was given alongside the study medication for hormone receptor-positive cancers. The study found that olaparib, taken twice daily for a year, improved overall survival rates and was generally well-tolerated by patients.

“Approximately 5% of patients diagnosed with breast cancer have an underlying inherited BRCA1 or BRCA2 gene mutation,” explains Professor Phillips, highlighting the importance of the results. “This equates to roughly 1,000 [of the] women in Australia each year [who are] diagnosed with breast cancer. Typically, these women are diagnosed with breast cancer at a young age and may have a more aggressive form of the disease.”

Olaparib works by targeting a specific weakness in the cancers of people with BRCA1 or BRCA2 mutations, making cancer cells more likely to die when treated with the drug.

With an average follow-up period of 3.5 years, the OlympiA trial showed a 32% reduction in breast cancer deaths in patients whose cancer had not spread beyond the breast or local lymph nodes. The four-year overall survival rate was 89.8% in the olaparib group compared to 86.4% in the placebo group, and no new safety concerns were identified.

These findings emphasise the importance of genetic testing for inherited BRCA1 and BRCA2 abnormalities in women with breast cancer to determine if they might benefit from this new treatment. Professor Phillips expressed her gratitude to trial participants and participating institutions, recognising the “significant and practice-changing results that provide a new treatment option for these patients”.


Overall survival in the OlympiA phase III trial of adjuvant olaparib in patients with germline pathogenic variants in BRCA1/2 and high-risk, early breast cancer.

Geyer CE Jr, Garber JE, Gelber RD, et al. Ann Oncol. 2022 Dec;33(12):1250-1268. Epub 2022 Oct 10. PMID: 36228963. Doi: 10.1016/j.annonc.2022.09.159.


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Professor Kelly-Anne Phillips

The Breast Cancer Trials Study Chair of the OlympiA clinical trial, Professor Kelly-Anne Phillips.

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