CHICAGO – Median overall survival (OS) in patients with HER2-negative metastatic breast cancer (mBC) and germline BRCA mutation (gBRCAm), although not statistically significant, was 2.2 months longer with olaparib versus physician’s choice chemotherapy (TPC), according to the final analysis of the OlympiAD study.
The results suggested the possibility of greater benefit among chemotherapy naive patients for metastatic breast cancer, with no cumulative toxicity reported with extended exposure, Mark E. Robson, MD, said at the annual meeting of the American Association for Cancer Research.
OlympiAD was a randomized, controlled, open-label, multicenter, phase 3 study of olaparib tablet monotherapy (300 mg, twice daily) compared with predeclared TPC monotherapy (capecitabine, vinorelbine, or eribulin). Patients were stratified by prior chemotherapy, prior platinum, and receptor status (ER+ and/or PR+ vs. TNBC). Of 302 randomized patients, 205 received olaparib and 91 received TPC (6 TPC patients declined treatment). Eligible patients had HER2-negative mBC and a germline BRCA mutation. In addition, patients should have received less than or equal to two chemotherapy lines in the metastatic setting, with prior anthracycline and taxane treatment either as (neo)adjuvant therapy or in the metastatic setting.
The data presented at AACR was a follow-up on the primary progression-free survival (PFS) analysis, which demonstrated significant benefit in olaparib over standard chemotherapy TPC (7.0 vs 4.2 months, HR 0.58, 95% confidence interval, 0.43-0.80, P less than .001). Overall response rate (ORR) in the olaparib arm was double of that observed on the TPC arm in measurable disease patients (59.9% vs. 28.8%).