OlympiA at six years: sustained benefit of adjuvant olaparib in high-risk BRCA-associated early breast cancer

Garber JE, Cameron D, Campbell C, et al. Sustained benefit of adjuvant olaparib in women with germline BRCA1- and BRCA2-associated high-risk HER2-negative early breast cancer: Updated results from the OlympiA phase III trial. Ann Oncol. Published online 24 August 2026. doi:10.1016/j.annonc.2026.08.002.

Updated six-year data from the phase III OlympiA trial provide reassuring evidence that the benefit of adjuvant olaparib is sustained in patients with germline BRCA1/2 pathogenic or likely pathogenic variants and high-risk, HER2-negative early breast cancer. The trial randomised 1,836 patients with stage II–III, HER2-negative breast cancer to one year of olaparib or placebo after local treatment and (neo)adjuvant chemotherapy. At a median follow-up of 6.1 years, invasive disease-free survival was 79.6% with olaparib versus 70.3% with placebo (HR 0.65; absolute difference 9.4%). Distant disease-free survival was 83.5% versus 75.7% (HR 0.65; absolute difference 7.8%), and overall survival 87.5% versus 83.2% (HR 0.72; absolute difference 4.4%, CI 0.9% to 6.7%). Reassuringly, no new long-term safety signal emerged; myelodysplastic syndrome/acute myeloid leukaemia remained uncommon (0.4% versus 0.7%).

These results strengthen, rather than alter, established practice: an overall-survival benefit had already been demonstrated, while the current analysis shows that it is durable well beyond the one-year treatment period. The efficacy analyses are descriptive, as formal statistical thresholds were crossed in earlier analyses.

The findings apply to a selected high-risk population and should not be extrapolated to all germline BRCA1/2 carriers. Longer follow-up remains important for rare late toxicities and second malignancies.
For breast teams, the key practical message is straightforward: timely germline BRCA1/2 testing, combined with accurate pathological risk assessment, is essential to identify eligible patients promptly and ensure access to effective adjuvant therapy within the multidisciplinary pathway.

Summary Author: Ms Susanna Polotto, Consultant Plastic and Oncoplastic Breast Surgeon at Chesterfield Royal Hospital NHS Foundation Trust.