FDA approves PARP inhibitor olaparib for some BRCA-positive metastatic breast cancers

In January, the U.S. Food and Drug Administration approved olaparib (Lynparza), a PARP inhibitor, for the treatment of metastatic, HER2-negative breast cancer in people with an inherited BRCA gene mutation who have already been treated with chemotherapy. The medicine was first approved to treat BRCA-positive ovarian cancer in 2014.

Strong results from a breast cancer clinical trial of olaparib, called OlympiAD, were published last summer. After that, the medicine was granted priority review by the FDA because of its potential to significantly improve treatment of a serious condition. This process allowed it to move through the approval process more quickly.

Background

Everyone has BRCA1 and BRCA2 genes. But some people are born with mutations, or errors, in these genes. The mutations can greatly increase a person’s chance of getting certain diseases, including breast and ovarian cancer. And in a person who has breast cancer, a BRCA mutation may affect how the cancer responds to different treatments.

Olaparib, part of a family of medicines called PARP inhibitors, is a treatment for people who test positive for a BRCA mutation and are diagnosed with breast cancer. PARP inhibitors can cause cancer cells to die by stopping an enzyme in the body, known as PARP, from repairing cancer cell DNA.

The OlympiAD Trial

Researchers with the phase III OlympiAD trial wanted to learn how well olaparib works compared to standard chemotherapy. The trial included 302 people, all of whom had a BRCA1 or BRCA2 mutation and metastatic breast cancer that was either hormone receptor-positive and HER2-negative, or triple-negative. All of the participants had been treated with chemotherapy in the past, either for early-stage or metastatic breast cancer. They were randomly assigned to two treatment groups:

• 205 people took olaparib as a pill twice a day
• 91 people were treated with one of three standard chemotherapy medicines of their doctor’s choice

The researchers found that participants in the olaparib group went longer without the cancer growing or spreading. The median progression-free survival was

• 7 months in the olaparib group
• 4.2 months in the standard chemotherapy group

They also found the cancer shrunk in

• 59.9 percent of the olaparib group
• 28.8 percent of the standard chemotherapy group

Olaparib had fewer serious side effects than standard chemotherapy. Its most common serious side effects were low blood cell counts, which can cause fatigue and increase the risk of infection. Serious side effects were seen in

• 36.6 percent of the olaparib group
• 50.5 percent of the standard chemotherapy group

The OlympiAD trial marks the first time a PARP inhibitor showed a benefit in a phase III trial for people with breast cancer.

What This Means for You

As the first PARP inhibitor to be approved in breast cancer and the first medicine approved specifically for people who have breast cancer and a BRCA mutation, olaparib’s approval is exciting. It gives certain people another treatment option, one that may work better and have fewer side effects than standard chemotherapy. If you have triple-negative disease and a BRCA mutation, this may be the first time you’re able to have treatment that is not chemotherapy.

Before you get olaparib, you must have a test showing you have a harmful inherited mutation in the BRCA1 or BRCA2 genes. The FDA granted approved to a specific test called BRACAnalysis CDx, but there are other genetic tests available too.

Ask your doctor about olaparib, and about other PARP inhibitors, which could be available through a clinical trial.

More information about metastatic breast cancer is available here and more information about genetics and family risk is available here.