Interim findings from a real-world clinical study presented at the virtual 2020 ASCO Annual Meeting support the use of olaparib as an alternative to chemotherapy in patients with HER2-negative metastatic breast cancer with germline BRCA mutations.

“OlympiAD demonstrated the benefit of olaparib over standard of care in patients with HER2-negative metastatic breast cancer and germline BRCA mutations,” said Karen A. Gelmon, MD, Department of Medical Oncology, BC Cancer, Vancouver, Canada, and colleagues, who sought to evaluate the real-world safety and efficacy of olaparib monotherapy in this setting in the LUCY trial.

Between October 2018 and September 2019, a total of 252 patients (mean age, 46.2 years) with HER2-negative metastatic breast cancer with germline BRCA mutations were enrolled in the open-label, single-arm, phase 3b study.

These patients had received a taxane and/or anthracycline in the neoadjuvant/metastatic setting and ≤2 lines of chemotherapy at 160 sites across 15 countries.

Patients who were hormone receptor–positive had disease that progressed with previous endocrine therapy, and for them further endocrine therapy was considered inappropriate.

The primary end point of the study was investigator-defined progression-free survival (PFS), and secondary end points included overall survival, time to first subsequent therapy or death, and investigator-assessed clinical response rate.

The interim analysis was planned to take place after 160 PFS events.

Overall, treatment lasted for a median of 7.9 months, and the median PFS was 8.1 months (95% CI, 6.9-8.7; 166 events).

In addition, the median time to first subsequent therapy or death was 9.7 months (95% CI, 8.7-11.1) and the investigator-assessed clinical response rate was 48.6% (95% CI, 42.2-55.0).

Adverse events (AEs) of all grades reported in >20% of patients were nausea, anemia, asthenia, vomiting, and fatigue. Grade ≥3 AEs were reported in 24.6% of patients, and 4.4% of patients had an AE that led to treatment discontinuation.

“Interim results in this real-world population of patients with HER2-negative metastatic breast cancer with germline BRCA mutations were consistent with the OlympiAD study, and support olaparib as a chemotherapy-free alternative treatment for patients with advanced breast cancer with germline BRCA mutations,” Dr Gelmon and co-investigators concluded.—Hina M. Porcelli

Gelmon KA, Fasching PA, Couch F, et al. Real-world clinical effectiveness and safety of olaparib monotherapy in HER2-negative gBRCA-mutated metastatic breast cancer: Phase IIIb LUCY interim analysis. Presented at: the 2020 ASCO Annual Meeting; May 29-31, 2020. Abstract 1087.