The addition of therapy with the poly (ADP-ribose) polymerase (PARP) inhibitor olaparib in an adjuvant setting improves invasive disease-free survival in early-stage human epidermal growth factor receptor 2 (HER2)-negative breast cancer with germline BRCA1 or BRCA2 mutations, according to a study scheduled for presentation June 6 at the American Society of Clinical Oncology annual meeting and simultaneously published June 3 in the New England Journal of Medicine.

Andrew Tutt, M.B., Ch.B., Ph.D., from King’s College London in the United Kingdom, and colleagues conducted a randomized phase 3 trial involving 1,836 patients with high-risk early breast cancer that was negative for HER2 and had germline BRCA1 or BRCA2 mutations. All patients had received standard adjuvant or neoadjuvant chemotherapy, surgery, and radiation therapy if needed. Participants were randomly assigned to receive one year of continuous oral olaparib or placebo.

The researchers found that the independent data monitoring committee recommended data unblinding as the interim analysis at a median follow-up of 2.5 years indicated a significant benefit for olaparib versus placebo for invasive disease-free survival (hazard ratio, 0.58). Three-year invasive disease-free survival was 85.9 versus 77.1 percent. There was significant improvement in distant disease-free survival (DDFS) with olaparib versus placebo (hazard ratio, 0.57); three-year DDFS was 87.5 versus 80.4 percent. Overall survival was longer for olaparib, but the difference was not statistically significant at an interim analysis.

“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,” Tutt said in a statement.

Several authors disclosed ties to the biopharmaceutical and medical device industries, including AstraZeneca, which funded the study; one author submitted a European patent request.


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