Patients with BRCA-mutated, HER2-negative breast cancer who have previously been treated with chemotherapy are now approved to be treated with Lynparza.
The FDA’s approval is based on data showing that Lynparza — developed by AstraZeneca working together with Merck (known as MSD outside the U.S. and Canada) — prolonged the time patients lived without their cancer progressing, compared to standard-of-care chemotherapy.
“This additional approval for Lynparza represents an important advance for women with HER2-negative metastatic breast cancer with a germline BRCA mutation, which is a difficult-to-treat cancer,” Roy Baynes, senior vice president and head of Global Clinical Development, and chief medical officer at Merck, said in a press release.
Lynparza was initially approved by the FDA for the treatment of BRCA-mutated advanced ovarian cancer in December 2014. In August 2017, the regulatory agency extended its approval to include the maintenance treatment of recurrent ovarian, fallopian tube, or primary peritoneal cancer.
Lynparza is a PARP inhibitor, which acts to block DNA repair processes. The PARP enzyme is particularly important for DNA repair in people with BRCA mutations, and blocking it prevents the survival of tumors.
“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,” said Dave Fredrickson, executive vice president, head of the Oncology Business Unit at AstraZeneca.
“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,” he said.
Breast cancer patients’ eligibility for the treatment will be evaluated using a companion diagnostic — a test that is specific for a treatment — developed by Myriad Genetics.
Patients included in the trial were either triple negative — meaning that in addition to a lack of HER2, their cancer did not produce estrogen receptors (ER) or progesterone receptors (PR) — or were positive for hormone receptor (HR).
All patients were previously treated with chemotherapy. HR-positive patients had received at least one course of hormonal treatment or were ineligible for such treatment.
Data showed that among the 205 patients treated with Lynparza, the therapy reduced the risk of disease progression or death by 42 percent compared to chemotherapy. Lynparza also triggered a response in more patients than chemo — 52 percent responded to the treatment, compared to only 23 percent in the chemotherapy group.
Among those who responded, 7.8 percent had a complete eradication of their cancer. However, such a complete remission was seen in only 1.5 percent of patients treated with chemotherapy.
“Patients diagnosed with BRCA-related metastatic breast cancer are often younger than other breast cancer patients, and their disease is often much more aggressive and difficult to treat,” said Susan M. Domchek, executive director of the Basser Center for BRCA at the Abramson Cancer Center of the University of Pennsylvania.
“While there is currently no cure for metastatic breast cancer, today’s approval offers a new, targeted option that may help to delay disease progression for these patients,” added Domchek, who is a national leader on the OlympiAD trials.