ASCO 2021 Plenary - Practice changing OlympiA (CCTG MA36) trial results

Olaparib for BRCA 1/2 mutated and high-risk early breast cancer reduced recurrence risk by 42%
Practice changing OlympiA (CCTG MA36) trial results

CCTG MA36 OlympiA: A randomised, double-blind, parallel group, placebo-controlled multi-centre Phase III study to assess the efficacy and safety of olaparib versus placebo as adjuvant treatment in patients with germline BRCA1/2 mutations and high risk HER2 negative primary breast cancer who have completed definitive local treatment and neoadjuvant or adjuvant chemotherapy.

Giving olaparib to patients with certain BRCA-mutated breast cancer for 1 year after they were treated with chemotherapy, surgery, or radiation significantly improved disease-free survival, according to the results that were presented at the 2021 American Society of Clinical Oncology (ASCO) Annual Meeting and simultaneously published in the New England Journal of Medicine.

Results from the OlympiA (CCTG MA36) trial are important because they show that adding olaparib, a poly adenosine diphosphate-ribose polymerase (PARP) inhibitor, also benefits patients with early-stage disease, in addition to the drug’s known benefits in similar patients with metastatic disease. Patients in the study had BRCA 1/2 germline, or inherited, mutations and high-risk, early-stage cancer that was negative for human epidermal growth factor receptor 2 (HER2).

Andrew Tutt, chair of the OlympiA trial steering committee and professor of Oncology at The Institute of Cancer Research, London and Kings College London, said: “We are thrilled that our global academic and industry partnership in OlympiA has been able to help identify a possible new treatment option for patients with early-stage breast cancer and who have inherited mutations in their BRCA1 or BRCA2 genes. Patients with early-stage breast cancer who have inherited BRCA mutations are typically diagnosed at a younger age compared to those without such a mutation. Olaparib has the potential to be used as a follow-on to all the standard initial breast cancer treatments to reduce the rate of life-threatening recurrence and cancer spread for many patients identified through genetic testing to have mutations in these genes.”

The CCTG was one of the many cooperative groups contributing to this international trial that has demonstrated such exciting results. Canada recruited 34 women to the study and screened 226 for eligibility. Dr. Andrea Eisen from the Odette Cancer Centre at Sunnybrook was the Canadian Study Chair and championed this trial for many years. As part of this study, Dr. Eisen provided remote genetic counseling for women who otherwise did not have access to this service and would not have been able to participate. Through Dr. Eisen's enthusiasm and commitment and that of CCTG centres and patients, Canada was able to make a meaningful contribution to this global trial that will change practice for women with early stage breast cancer who have mutations in BRCA1 and BRCA2 genes.

Inherited mutations cause between 5% and 10% of breast cancers, but these cancers can be more aggressive and deadly. While the lifetime risk of breast cancer is about 12% for women overall, for women with BRCA mutations, it’s 72%. These women also tend to develop breast cancer at younger ages and in both breasts than those without the mutation.