OlympiAD’s positive results spell good news for olaparib in breast cancer

Study details

OlympiAD, which was funded by AstraZeneca, enrolled patients with HER2-negative metastatic breast cancer and a centrally confirmed germline (inherited) BRCA mutation who had received anthracyclines and taxanes, and up to two lines of chemotherapy for metastases.

They were randomized 2:1 to open-label treatment with either olaparib (300 mg., twice daily) or single-agent chemotherapy of the treating physician’s choice among three options (capecitabine, eribulin, or vinorelbine). A tablet formulation and dose of olaparib were used that differ from the currently approved capsule formulation and dose to reduce pill burden, Dr. Robson noted.

The patients were about equally split between BRCA1 and BRCA2 mutations, and between hormone receptor–positive disease and triple-negative disease, he reported. The majority (71%) had received chemotherapy for metastases, and a sizable minority (28%) had received prior platinum in the (neo)adjuvant or metastatic setting.

With a median follow-up of about 14.5 months, median progression-free survival assessed by central radiologic review was 7.0 months with olaparib and 4.2 months with chemotherapy (hazard ratio, 0.58; P = .0009).

The median time to investigator-reported second progression or death was also longer with olaparib (13.2 vs. 9.3 months; HR, 0.57; P = .0033).

Median overall survival was about 19-20 months in each group and not significantly different in an interim analysis.

The olaparib group had lower rates of grade 3 or worse adverse events (36.6% vs. 50.5%) and treatment discontinuation because of adverse events (4.9% vs. 7.7%).

The main adverse event of any grade with olaparib was nausea, which was usually mild; only about a quarter of affected patients required antiemetics, according to Dr. Robson. Patients also commonly experienced anemia, requiring transfusion in some cases, and fatigue.

Dr. Robson disclosed that he has a consulting or advisory role with McKesson and AstraZeneca; receives honoraria, travel, accommodations, and/or expenses from AstraZeneca; rand receives research funding (institutional) from AstraZeneca, Abbvie, Myriad Genetics, Biomarin, Medivation, and Tesaro.