Lynparza Following Standard of Care Treatments Effective in Some Patients with High-Risk Breast Cancer

The use of Lynparza (olaparib) following standard-of-care treatments — including surgery, chemotherapy, hormone therapy or radiation therapy — in patients with BRCA1/2-mutant, early HER2-negative breast cancer who are at a high risk for disease recurrence was associated with meaningful benefits after one year of treatment, according to study results.

Findings from the phase 3 OlympiA trial, which were presented during a press briefing ahead of the 2021 American Society of Clinical Oncology (ASCO) Annual Meeting, indicated that after a median follow-up of 2.5 years, patients who received Lynparza experienced a 42% reduction in invasive disease-free survival, including local and metastatic recurrence of breast cancer, other new cancers, and death due to any cause.

“The OlympiA study is the first to report the benefits of (an adjuvant) PARP inhibitor for early forms of germline BRCA1/2–mutation associated cancer,” presenting study author Andrew Tutt, head of the Division of Breast Cancer Research and director of the Breast Cancer Now Toby Robins Research Centre at The Institute of Cancer Research in the United Kingdom, said. “Patients who received (Lynparza) after surgery and chemotherapy were more likely to be alive without cancer, (as well as) avoid metastasis than the patients who received placebo.”

Patients with HER2-negative early breast cancer who harbor a BRCA1/2 mutation, which are present in approximately 5% of all breast cancers, are at a high risk of disease recurrence. Although outcomes have been positive for patients with these mutations who have received standard treatments such as surgery, radiotherapy, and chemotherapy, the risk of recurrence remains high for some patients. As such, additional novel targeted therapies are needed to reduce the risk of recurrence in this patient population.

Lynparza is a PARP inhibitor that targets DNA repair defects in certain germline-mutant cancers and was previously approved by the Food and Drug Administration (FDA) in January 2018 for the treatment of patients with germline BRCA-positive, HER2-negative metastatic breast cancer. As such, investigators sought to examine the agent in patients with germline BRCA–mutated, HER2-negative early breast cancer.

The study authors enrolled 1,836 patients with HER2-negative breast cancer harboring a germline BRCA mutation. Patients were randomized to receive either oral Lynparza (921 patients) twice daily for one year or placebo (915 patients). Additionally, patients needed to have been treated for early stage (stage 2 to 3) breast cancer and have completed surgery and chemotherapy, with or without radiotherapy. Inclusion criteria also required that patients have a high risk of disease recurrence. Those who had received prior treatment with a PARP inhibitor were not eligible to enroll.

Assessing invasive disease-free survival was the main goal of the study. Additional goals included measuring disease-free survival, overall survival, health-related quality of life and safety.

Additional findings indicated that after a median follow-up of 2.5 years, patients who were treated with Lynparza experienced a 43% reduction in distant disease-free survival, including metastatic disease, new cancer, and death due to any cause.

While fewer deaths were reported in patients receiving Lynparza compared to placebo, overall survival was not significantly different between the two treatment groups at a median follow-up of 2.5 years.

As for safety, the side effect profile associated with Lynparza was consistent with what has been previously reported with the agent. Additionally, treatment with Lynparza did not increase serious side effects, including hospital admissions or occurrences of other cancers such as leukemia. However, serious or severe side effects were reported more often in patients receiving treatment with study drug, and included anemia (9%), neutropenia (5%), leukopenia (3%), and fatigue (2%).

The most common side effects of any severity reported in patients who received Lynparza included, but were not limited to, nausea (57%), fatigue (40%) and vomiting (23%). Moreover, the most common side effect of any severity in the placebo group was fatigue (27%), nausea (23%), headache (17%), diarrhea (14%) and joint pain (12%).

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