ERBB2 and breast cancer: PARP inhibitors were also shown to be effective when used in the adjuvant setting in patients with early stage high-risk HER2-negative breast cancer with P/LP BRCA1/2 variants; patients in the OlympiA trial receiving adjuvant olaparib had significantly longer overall survival (OS); 4-year OS was 89.8% in the olaparib group and 86.4% in the placebo group (95% CI, 0.1% - 6.8%) (45, 46).