PARP Inhibitors

Poly(ADP-ribose) polymerase (PARP) is an enzyme that helps repair DNA damage. PARP inhibitors are drugs that try to keep cancer cells from repairing damaged tumor DNA, leading to tumor cell death.

Drug name

Brand name

Used to treat early or metastatic breast cancer?



Early and metastatic breast cancer



Metastatic breast cancer

PARP inhibitors and BRCA1 and BRCA2 inherited gene mutations

PARP inhibitors appear to hold the most promise for people who have a BRCA1 or BRCA2 (BRCA1/2) inherited gene mutation [70-71,158-159].

BRCA1/2-related breast cancers have problems repairing tumor DNA. These breast cancers seem to be sensitive to DNA damage caused by PARP inhibitors. Treating BRCA1/2-related breast cancers with a PARP inhibitor makes it harder for the breast cancer to repair itself, leading to tumor cell death.

Learn about genetic testing to guide breast cancer treatment.

Learn more about BRCA1/2 inherited gene mutations.

Olaparib (Lynparza) and early breast cancer treatment

Olaparib (Lynparza) is FDA-approved for the treatment of HER2-negative early breast cancer at high risk of recurrence in people who have a BRCA1 or BRCA2 (BRCA1/2) inherited gene mutation and have been treated with chemotherapy.

Study findings have shown people with a BRCA1/2 gene mutation who had HER2-negative breast cancer at high risk of recurrence and got olaparib had a lower risk of breast cancer recurrence and better survival than those who didn’t get olaparib [160]. Olaparib was given after chemotherapy was completed [160].

Olaparib is a pill. It’s taken twice a day, every day for a year [10].

You start taking olaparib after you’ve completed chemotherapy (and after radiation therapy, if you’re getting radiation therapy) [10]. Olaparib may be taken at the same time as hormone therapy [10].

Learn about survival and the risk of breast cancer recurrence after treatment.

Olaparib and genetic testing for BRCA1 and BRCA2 inherited gene mutations

Olaparib is only used to treat people with BRCA1 and BRCA2 (BRCA1/2) inherited gene mutations. So, you’ll need to get genetic testing for BRCA1/2 inherited gene mutations if olaparib is being considered in your treatment plan.

Learn about genetic testing and genetic counseling.

Learn more about BRCA1/2 inherited gene mutations.

Side effects of olaparib

Before you begin taking olaparib, talk with your health care provider about possible side effects and how to manage them.


Side Effects


Possible side effects include anemia (low red blood cell counts), low white blood cell counts, nausea, vomiting and fatigue.

In rare cases, olaparib can cause acute myeloid leukemia.

Adapted from select source [161].

Under study – PARP inhibitors and neoadjuvant therapy

Olaparib and another PARP inhibitor, talazoparib (Talzenna), each in combination with neoadjuvant chemotherapy (given before surgery), are under study for the treatment of early triple negative breast cancer [72,162].

Learn more about neoadjuvant therapy.

PARP inhibitors and metastatic breast cancer treatment

The PARP inhibitors olaparib (Lynparza) and talazoparib (Talzenna) are FDA-approved for the treatment of HER2-negative metastatic breast cancer in people who have a BRCA1 or BRCA2 inherited gene mutation.

Learn more about PARP inhibitors for the treatment of metastatic breast cancer.

Learn about emerging areas in treatment with PARP inhibitors for metastatic breast cancer.

Treatment guidelines

Although the exact treatment for breast cancer varies from person to person, evidence-based guidelines help make sure high-quality care is given. These guidelines are based on the latest research and agreement among experts.

The National Comprehensive Cancer Network (NCCN) and the American Society of Clinical Oncology (ASCO) are respected organizations that regularly review and update their guidelines.

In addition, the National Cancer Institute (NCI) has treatment overviews.

Talk with your health care team about which treatment guidelines they follow.

After you get a recommended treatment plan from your health care team, study your treatment options. Together with your health care team, make thoughtful, informed decisions that are best for you. Each treatment has risks and benefits to consider along with your own values and lifestyle.

Prescription drug assistance

Prescription drug costs can quickly become a financial burden for you and your family.

Medicare and many insurance companies offer prescription drug plans. One may already be included in your policy, or you may be able to buy an extra plan for prescriptions.

Olaparib (Lynparza) is a pill, so it’s covered under your health insurance plan’s prescription drug benefit rather than the plan’s medical benefit. This means there are usually out-of-pocket costs, which can add up over time.

You may qualify for programs that help with drug costs or offer low-cost or free prescriptions.

Many cancer centers have financial counselors who can discuss insurance and cost coverage with you.

Learn more about insurance plans and prescription drug assistance programs.

Learn more about other financial assistance programs.

Komen Financial Assistance Program

Susan G. Komen® created the Komen Financial Assistance Program to help those struggling with the costs of breast cancer treatment by providing financial assistance to eligible individuals.

To learn more about this program and other helpful resources, call the Komen Breast Care Helpline at 1-877 GO KOMEN (1-877-465-6636) or email

Se habla español.

Susan G. Komen®‘s position on fairness in oral cancer drug coverage

Insurance coverage of oral cancer drugs

Cancer medications given through an IV into a vein or by an injection (under the skin or into a muscle) are usually covered under a health insurance plan’s medical benefit. However, oral cancer drugs (cancer medications that are pills) are usually covered under a health insurance plan’s prescription drug benefit.

As a result, people often find themselves facing high out-of-pocket costs when filling prescriptions for oral cancer drugs. Sometimes these costs can be thousands of dollars a month.

The impact of high cost-sharing

High prescription drug costs and the resulting out-of-pocket burden on patients are a barrier to care. They can prevent people from getting the medications prescribed by their health care providers.

No one should be forced to get less appropriate treatment because an insurer gives more coverage for IV and injectable drugs than for pills.

Efforts to increase fairness in drug coverage

Komen supports state and federal efforts to require insurers to provide the same or better coverage for oral cancer drugs as they do for IV and injectable cancer drugs. This would help make sure patients have access to affordable, appropriate treatment.

Become a Komen Advocacy Insider

Sign up to be a Komen Advocacy Insider and get informed when action is needed on drug coverage issues at the state or national level.

Clinical trials

Research is ongoing to improve all areas of treatment for breast cancer.

New therapies are being studied in clinical trials. The results of these studies will decide whether these therapies become part of the standard of care.

After discussing the benefits and risks with your health care provider, we encourage you to consider joining a clinical trial.

Susan G. Komen® Patient Care Center

If you or a loved one needs information or resources about clinical trials, the Patient Care Center can help. Contact the Komen Breast Care Helpline at 1-877-465-6636 or email

Se habla español. in collaboration with Komen offers a custom matching service to help find clinical trials that fit your needs.

Learn what Komen is doing to help people find and participate in breast cancer clinical trials, including trials supported by Komen.

Learn more about clinical trials.


Komen Perspectives

Read our perspective on clinical trials.*

Learn More

Susan G. Komen® Support Resources

  • Do you need help? We’re here for you. The Komen Patient Care Center is your trusted, go-to source for timely, accurate breast health and breast cancer information, services and resources. Our navigators offer free, personalized support to patients, caregivers and family members, including education, emotional support, financial assistance, help accessing care and more. Get connected to a Komen navigator by contacting the Breast Care Helpline at 1-877-465-6636 or email to get started. All calls are answered Monday through Thursday, 9 a.m to 7 p.m. ET and Friday, 9 a.m. to 6 p.m. ET. Se habla español.
  • The Komen Breast Cancer and Komen Metastatic (Stage IV) Breast Cancer Facebook groups are places where those with breast cancer and their family and friends can talk with others for friendship and support.
  • Our fact sheets, booklets and other education materials offer additional information.

*Please note, the information provided within Komen Perspectives articles is only current as of the date of posting. Therefore, some information may be out of date.

Updated 04/12/24


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