Further Efficacy Outcomes From OlympiAD Trial of Olaparib in Advanced Breast Cancer
Previously reported data from the phase III OlympiAD trial revealed that the poly (ADP-ribose) polymerase (PARP) inhibitor olaparib delayed progression of BRCA-related advanced breast cancer by about 3 months compared with standard chemotherapy. At the European Society for Medical Oncology (ESMO) 2017 Congress, Suzette Delaloge, MD, Head of the Breast Cancer Department at Gustave Roussy Institute, Paris, presented further efficacy outcomes from the trial, showing continued benefits with the PARP inhibitor in patients with HER2-negative breast cancer with a germline BRCA mutation (Abstract 243PD).
The randomized OlympiAD study focused on patients with HER2-negative metastatic breast cancer and a germline BRCA mutation who had received up to two prior lines of chemotherapy. Patients were randomized 2:1 to receive oral olaparib monotherapy (n=205) or physician’s choice of single-agent chemotherapy with capecitabine, eribulin, or vinorelbine (n=97).
In patients with measurable disease, the objective response rate was 59.9% with olaparib and 28.8% with chemotherapy. Median best percentage change from baseline in the target lesion size in the olaparib group was 45.1%, compared to 14.8% in the chemotherapy group.
Olaparib monotherapy led to a doubling of objective response rate versus chemotherapy and a larger reduction in target lesion size. The investigators suggest their findings indicate a more pronounced depth of response in this patient population. Progression-free survival was also longer with olaparib than with chemotherapy, irrespective of tumor burden and location.