US regulators have further expanded the scope of AstraZeneca and MSD’s Lynparza to include treatment of patients with BCRA-mutant metastatic breast cancer.

More specifically, the US Food and Drug Administration is allowing the drug’s use to in patients with deleterious or suspected deleterious germline BRCA-mutated (gBRCAm), human epidermal growth factor receptor 2 (HER2)-negative metastatic breast cancer who have been previously treated with chemotherapy in the neoadjuvant, adjuvant or metastatic setting.

Patients with hormone receptor positive (HR+) breast cancer should have been treated with a prior endocrine therapy or be considered inappropriate for endocrine therapy.

Patients are selected for therapy based on an FDA-approved companion diagnostic from Myriad Genetics.

“This new approval for Lynparza makes it the first and only PARP inhibitor approved in metastatic breast cancer, and the only PARP inhibitor approved beyond ovarian cancer,” noted Dave Fredrickson, head of the Oncology Business Unit at AZ.

“This is significant for breast cancer patients, as the identification of BRCA status, in addition to hormone receptor and HER2 status, becomes a potentially critical step in the management of their disease.”

Approval was based on data from the Phase III OlympiAD trial, which showed that patients with HER2-negative germline BRCA1 or BRCA2-mutated breast cancer treated with Lynparza (olaparib) had a 42-percent reduced risk of disease worsening or death compared to those who received chemotherapy.

Also, the objective response rate (ORR) was more than doubled, with 59.9 percent of patients in the Lynparza arm showing response to treatment, compared to 28.8 percent of patients treated with chemotherapy, while no new safety signals were identified.

Olaparib was first developed as a cancer treatment following landmark research by UK scientists at the Breast Cancer Now Research Centre at The Institute of Cancer Research, London in 2005, who showed for the first time that cancer cells with BRCA1 and BRCA2 mutations were very sensitive to PARP inhibitors.

“This important drug can offer around three extra months before the disease progresses compared to chemotherapy – and a better quality of life during that time – which could be invaluable to so many women and their families,” said Fiona Hazell, Director of Policy and Engagement at Breast Cancer Now.

“Having been fast-tracked for approval in the United States, we now look forward to olaparib being submitted to the EMA for licensing in this indication to open the door for future access for UK patients, as well as research to uncover how we can best identify which patients will benefit the most.”

In the US Lynparza is already on the market for the treatment of women with BRCA-mutated, advanced ovarian cancer who have received three or more prior lines of chemotherapy, and for maintenance treatment of certain patients with recurrent epithelial ovarian, fallopian tube or primary peritoneal cancer.