Data from the Phase III OlympiAD trial, showing the final overall survival (OS) results for olaparib in metastatic breast cancer was presented at the American Association for Cancer Research (AACR) Annual Meeting in Chicago, April 14-18, 2018.
The trial compared olaparib with chemotherapy (physician’s choice of capecitabine, eribulin or vinorelbine) for patients with germline BRCA-mutated (gBRCAm) HER2-negative metastatic breast cancer (MBC) and met its primary endpoint of progression-free survival (PFS).
Results at AACR include updated findings from the secondary endpoint of overall survival (OS).
This follows the FDA approval for olaparib in this indication in January.
While the trial was not powered to demonstrate a statistically-significant difference, the median OS was 19.3 months in patients treated with olaparib and 17.1 months for patients treated with chemotherapy (HR 0.90; 95% CI 0.66-1.23; p=0.513). At the final OS data cut-off (64% maturity), nearly 13% of patients remained on olaparib and no patients remained on chemotherapy.
Sean Bohen, Executive Vice President, Global Medicines Development and Chief Medical Officer at AstraZeneca, said “OlympiAD is the first Phase III trial to demonstrate disease control with a PARP inhibitor in BRCA-mutated HER2-negative metastatic breast cancer. While the trial was not powered to show overall survival compared to chemotherapy, the results are another encouraging marker in the use of olaparib for this patient population.”
Roy Baynes, Senior Vice President and Head of Global Clinical Development, Chief Medical Officer, Merck Research Laboratories, said “For patients and physicians, these results are meaningful in that they support the progression-free survival endpoint – which showed that patients treated with olaparib gained seven months chemotherapy-free time – and reinforce the importance of identifying BRCA status to optimize metastatic breast cancer management.”
Olaparib is indicated in patients with gBRCAm HER2-negative MBC previously treated with chemotherapy.
Hormone receptor (HR)-positive breast cancer should have been treated with prior endocrine therapy or be considered inappropriate for endocrine treatment.
An FDA-approved companion diagnostic is required for this indication.
When analyzing the predefined subgroups, the results were consistent with the overall analysis, which did not show a statistically-significant difference between arms.
The greatest difference was seen in patients who had not received chemotherapy in the metastatic setting with a median difference in OS of 7.9 months with olaparib (HR 0.51; 95% CI 0.29-0.90; nominal p=0.02; median 22.6 vs 14.7 months).