Olaparib May Not Improve Overall Survival vs Chemotherapy in Breast Cancer

Compared with chemotherapy, olaparib monotherapy did not significantly improve overall survival (OS) among patients with HER2-negative metastatic breast cancer (mBC) with a germline BRCA mutation (gBRCAm), according to findings presented at the 2018 American Association for Cancer Research Annual Meeting in Chicago, Illinois.¹

A previous report of the phase 3 OlympiAD study (ClinicalTrials.gov Identifier: NCT02000622) demonstrated that olaparib monotherapy improves progression-free survival (PFS) vs chemotherapy treatment of physician’s choice (TPC), but OS data were not mature.

For OlympiAD, 302 patients with HER2-negative mBC and a gBRCAm were randomly assigned to receive oral olaparib 300 mg twice daily or single-agent TPC (capecitabine, vinorelbine, eribulin). Eligible patients had received 2 or fewer previous lines of chemotherapy.

At the time of final analysis, 192 of 302 patients had died. The median follow-up was 18.9 months and 15.5 months for patients in the olaparib arm and TPC arm, respectively.

Patients in the olaparib group had a median OS of 19.3 months compared with 17.1 months among patients who received TPC (hazard ratio [HR], 0.90; 95% CI, 0.66-1.23); this finding was, however, not significant.

Grade 3 or worse adverse events were observed in 38% of patients in the olaparib arm compared with 50% of patients in the TPC arm. The safety profile of olaparib remained consistent with previous findings, suggesting that long-term olaparib therapy does not lead to cumulative toxicity.

The authors also noted that a greater number of patients who received TPC received additional treatment with PARP inhibitors, platinum/hormonal therapies, and cytotoxic chemotherapy compared with those treated with olaparib.

Read more of Cancer Therapy Advisor‘s coverage of the American Association for Cancer Research (AACR) 2018 meeting by visiting the conference page.

Reference

1. Robson ME, Im SA, Senkus E, et al. OlympiAD final overall survival: olaparib versus chemotherapy treatment of physician’s choice (TPC) in patients with HER2-negative metastatic breast cancer (mBC) and a germline BRCA mutation (gBRCAm). Oral presentation at: 2018 American Association for Cancer Research Annual Meeting; April 14-18, 2018; Chicago, IL.