PARP Inhibitor Significantly Improved Disease-Free Survival in Patients With High-Risk Early-Stage HER2-Negative Breast Cancer with BRCA 1/2 Mutations

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For immediate release
June 3, 2021


Rachel Cagan

ASCO Perspective
“OlympiA’s findings highlight the need for genetic testing for BRCA mutations in patients diagnosed with high-risk early-stage breast cancer. These results could have an important impact on treatment decisions for this patient population, possibly including the use of a PARP inhibitor in the adjuvant setting,” said ASCO President Lori J. Pierce, MD, FASTRO, FASCO.

ALEXANDRIA, Va. — The addition of 1 year of the PARP inhibitor olaparib after completion of standard neoadjuvant or adjuvant chemotherapy, surgery and any radiation therapy needed, significantly improved invasive disease-free (IDFS) and distant disease-free survival (DDFS) in patients with BRCA1/2 germline mutations and high-risk early-stage breast cancer that is negative for human epidermal growth factor receptor 2-(HER2), according to new research to be presented at the 2021 American Society of Clinical Oncology (ASCO) Annual Meeting.

Study at a Glance


Effect of a PARP inhibitor in the adjuvant setting after (neo)adjuvant chemotherapy in certain patients with breast cancer


1,836 patients with germline (inherited) BRCA1 or BRCA2 mutations and high-risk early breast cancer that was negative for overexpression of HER2


  • At a pre-specified interim analysis, the estimated 3-year IDFS (patients alive and free of recurrent invasive breast cancer and new second cancers) was 85.9% for patients who received olaparib compared with 77.1% with those who received placebo. At the time of the interim analysis the median follow up was 2.5 years.
  • Also, the estimated 3-year survival free from distant metastatic disease (DDFS) was 87.5% and 80.4% of patients in the olaparib and placebo groups, respectively.


The results of this study may change the standard of care in adjuvant systemic therapy for patients with germline BRCA1/2 mutations and early-stage breast cancer that is negative for HER2 — diagnosed at the potentially curable early-stage — who have a level of risk of recurrence requiring adjuvant chemotherapy.

Key Findings
In the OlympiA study, patients who received standard treatment plus placebo had an estimated 3-year IDFS — being alive and free of recurrent invasive breast cancer and new second cancers — of 77.1%. With the additional administration of 1 year of the oral PARP inhibitor olaparib, the estimated 3-year IDFS was improved to 85.9%. The estimated 3-year DDFS was also improved from 80.4% with placebo to 87.5% with olaparib.

While 3-year estimated overall survival (OS) was greater with olaparib, the difference was not statistically significant at the time of this interim analysis at 2.5 years median follow up. 

Adverse events (AEs) were consistent with those previously reported with olaparib treatment. Serious adverse events (SAEs) did not occur more frequently with olaparib than with placebo.

“The OlympiA study results, the first reporting the effects of a PARP inhibitor as an “adjuvant therapy” on survival endpoints, suggest a possible addition to the standard of care for patients with germline BRCA1/2 mutation-associated early breast cancer who have levels of recurrence risk requiring neoadjuvant or adjuvant chemotherapy” said lead author Professor Andrew Tutt, MB ChB, PhD, FMedSci who is the Head of the Division of Breast Cancer Research and Director of the Breast Cancer Now Toby Robins Research Centre at the Institute of Cancer Research, London and the Breast Cancer Now Research Unit at Guy’s Hospital King’s College London.

In the U.S., 5-10% of breast cancers are related to an inherited gene mutation.Patients with newly diagnosed breast cancers associated with these mutations can present with aggressive, high risk disease. Following completion of multi-modality therapy, which includes surgery, radiation, and chemotherapy, recurrence rates can remain high. There is an unmet need to identify additional novel and effective therapies.

Olaparib is an oral targeted therapy — a poly (ADP-ribose) polymerase (PARP) inhibitor — that is already approved for patients with germline BRCA1 or BRCA2 mutations and metastatic breast cancer.2

The OlympiA trial is the first phase III study to report the effect of a PARP inhibitor in any adjuvant setting and in this context is focused on patients with germline BRCA1 or BRCA2 mutations and early-stage, high-recurrence risk breast cancer, following completion of standard multi-modality therapy, which includes a combination of chemotherapy drugs.

About the Study
The randomized, double-blind phase III OlympiA study enrolled 1,836 patients with high-risk early breast cancer that was negative for human epidermal growth factor receptor 2-(HER2) and had germline BRCA1 or BRCA2 mutations, including triple negative and hormone receptor positive breast cancer.

All participants had already received standard adjuvant or neoadjuvant chemotherapy, surgery and radiation therapy if needed for early-stage breast cancer disease. Participants were selected based on defined pathological selection criteria that were different in triple negative and hormone receptor positive breast cancer but were designed to exclude patients at lower risk of invasive disease recurrence. Patients were randomized to receive either olaparib or placebo for 1 year.

The primary endpoint was IDFS; secondary endpoints were DDFS and OS. The study has reported early at a median follow up of 2.5 years after a planned interim analysis that was reviewed by an independent Data Monitoring Committee.

OlympiA is an academia-industry partnership trial, being coordinated worldwide by the Breast International Group (BIG), in partnership with Frontier Science & Technology Research Foundation (FSTRF), NRG Oncology (National Cancer Institute-supported National Clinical Trials Network Group) and the study sponsors.

Next Steps
The patients in the study continue to be followed up for effects on overall survival and long-term safety endpoints.

View the full abstract 

View the author disclosures

For your readers:

View the disclosures for the 2021 Cancer Communications Committee:  

View the disclosures for Dr. Gralow 

View the disclosures for Dr. Pierce: 



1. National Cancer Institute, Genetics of breast and gynecologic cancers (PDQ®) – health professional version,, 2020.

2. U.S. Food and Drug Administration, FDA approves olaparib for germline BRCA-mutated metastatic breast cancer,, 2018.


Dr. Tutt's Embargoed Presscast Presentation

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