Olaparib

Olaparib (Lynparza) is a targeted therapy approved by the Food and Drug Administration. It is used to treat early-stage or metastatic breast cancer that is either hormone receptor-positive and HER2-negative, or triple-negative, in people with an inherited BRCA gene mutation who have already been treated with chemotherapy.

Olaparib was the first PARP inhibitor to be FDA approved in breast cancer. It was also the first medicine approved specifically for people who have breast cancer and an inherited (also called germline) BRCA mutation. The FDA initially approved it for use in ovarian cancer in 2014. Olaparib is now used to treat breast, pancreatic, and prostate cancers as well.

How olaparib works

Olaparib is a PARP inhibitor. PARP (or poly (ADP-ribose) polymerase) is an enzyme in the body that helps repair DNA damage to cells, even cancer cells. DNA damage can occur for any number of reasons. PARP inhibitors treat cancer by stopping PARP from repairing cancer cell DNA. Instead, cancer cells die. People with inherited BRCA mutations are more likely to respond to PARP inhibitors because their cells are already less able to repair themselves.

In a clinical trial, researchers found that participants with metastatic breast cancer who took olaparib went about 3 months longer without the cancer growing or spreading than participants who got standard chemotherapy. The cancer was also about twice as likely to shrink in those who took olaparib.

A more recent clinical trial found that olaparib given for one year after standard treatment also has benefit for people with high-risk early-stage breast cancer who tested positive for an inherited BRCA mutation. After three years of follow-up, 86% of participants who took olaparib for a year were still cancer-free, compared with 77% of participants who did not take olaparib. Both groups had at least six cycles of chemotherapy before starting olaparib.

Who gets olaparib

Olaparib is approved for use in people who test positive for a BRCA1 or BRCA2 gene mutation inherited from a parent. It is now FDA approved for both high-risk early-stage and metastatic breast cancers that are HER2-negative. The cancer can be either hormone receptor-positive or triple-negative.

You must have already been treated with chemotherapy to get olaparib. If you have high-risk early-stage breast cancer, you likely will have had surgery as well. It does not matter if chemotherapy was given before or after surgery. People with hormone receptor-positive early-stage breast cancer will continue to take hormonal therapy while on olaparib. If you need radiation therapy, olaparib will be paused during your radiation regimen. This is because it’s not yet clear how safe it is to give olaparib and radiation at the same time.

The only way to know if you were born with a BRCA mutation is to get genetic testing for an inherited mutation. This testing is done using a blood, saliva, or cheek-swab test. The FDA recently approved the BRACAnalysis CDx test for people with high-risk, early-stage HER2-negative breast cancer who have not had genetic testing for an inherited mutation. This faster turnaround test can identify people with the BRCA gene mutation who may benefit from olaparib. If you are interested in this test or in genetic testing in general, talk with your doctor.

“Research is ongoing to see if olaparib can also be used for patients with acquired (also known as somatic) BRCA mutations that are not inherited, but only found in the tumor DNA, or for mutations other than BRCA 1 or 2 that are involved in DNA repair," Dr. Tripathy adds.

How olaparib is given

Olaparib is a pill. It is usually taken twice every day, at least 12 hours apart, with or without food. The pill must be swallowed whole, not crushed, dissolved, chewed, or divided. It is important to take these pills as prescribed. If you happen to miss a dose, just take the usual dose at the next scheduled time. Do not take a double dose.

Side effects and things to remember

In a clinical trial, researchers found olaparib had fewer serious side effects overall than standard chemotherapy. Its most common serious side effects are low blood cell counts, which can cause fatigue and increase the risk of infection. Rarely, low blood cells counts while taking PARP inhibitors are a sign of serious problems in the bone marrow, areas of fatty tissue in the bones in which blood cells are made. Because of this, your health care providers should do blood tests before you begin treatment with olaparib, and throughout your treatment with it.

Other common side effects include

• nausea and vomiting
• tiredness or weakness
• sore throat or runny nose
• diarrhea
• joint, muscle, and back pain
• headache
• constipation
• changes in the way food tastes
• loss of appetite
• mouth sores

Rarely, PARP inhibitors may cause serious lung problems. Though it’s unlikely you’ll have serious lung problems while taking olaparib, if you feel new or worsening shortness of breath, fever, coughing, or wheezing, tell your doctor right away.

Tell your doctor about any medicines, supplements, or herbal remedies you are taking before starting olaparib. Avoid eating or drinking any food with grapefruits, and a type of orange called a bitter orange or a Seville orange, which is often used in marmalade. These fruits can affect the way your body absorbs olaparib.

Tell your doctor if you are pregnant, breastfeeding, or planning to become pregnant or start breastfeeding. Olaparib may be dangerous to a fetus so it is recommended that you not take this medicine while pregnant. It is also advised that you avoid getting pregnant until at least 6 months after you have stopped treatment with it. It is not known if olaparib is transferred through breast milk, so you should not breastfeed while taking olaparib or for 1 month after you stop treatment.

Talk to your doctor about any side effects you experience and how to manage them.