What Women Need to Know About PARP Inhibitors

Almost all women are eligible for PARP inhibitor treatment after their initial debulking surgery and chemotherapy. But, according to Dr. John Nakayama, gynecologic oncologist at University Hospitals in Cleveland, "that doesn’t necessarily mean that everybody will have the same amount of benefit."

This treatment is recommended for women with a genetic predisposition for ovarian cancer because they carry BRCA1 or BRCA2, the most common gene mutations linked to ovarian cancer. Some women with BRCA mutations have homologous recombination deficiency, or HRD, a genetic factor in which cells have difficulty repairing themselves.

"Those are the people that are most likely to benefit from PARP inhibitors," says Dr. Nakayama. Because PARP inhibitors also prevent defective cancer cells from repairing damaged strands of DNA, having these mutations makes the drugs even more effective.

However, the American Society of Clinical Oncology (ASCO) guidelines recommend PARP inhibitors be offered to women, with or without genetic mutations, who are newly diagnosed with stage III or IV ovarian cancer and have improved with chemotherapy.

Which PARP Inhibitor is Right For You? 

There are currently three FDA-approved PARP inhibitors on the market, which can be used in the treatment or maintenance therapy for ovarian cancer:

• Olaparib (Lynparza)
• Niraparib (Zejula)
• Rucaparib (Rubraca)

Your doctor will choose the PARP inhibitor that will be most effective based on your tumor’s genetic profile, and your unique situation. Lynparza is approved specifically for women with BRCA mutations in their tumors. Zejula is approved for almost all women with ovarian cancer, after they have a complete or partial response to initial platinum-based chemotherapy. Lynparza is also approved in combination with Avastin (bevacizumab) for women with HRD.  Avastin is a blood vessel growth inhibitor, which works by starving the tumor of vital nutrients needed to grow.

Common Side Effects

"The side effects of PARP inhibitors are fairly manageable," says Dr. Nakayama. "They tend to be the worst when you first start them, and they depend on the PARP inhibitor."

Some of these side effects can include:

• Fatigue
• Nausea
• Low blood cell count
• Heartburn

"Some PARP inhibitors have more what we call hematologic toxicities," adds Dr. Nakayama. "Your platelets might drop or your red blood cells may drop more with some [drugs] versus others. Most people will have some sort of constellation of fatigue, a decrease in their blood counts, and nausea. Some people will have heartburn. The big ones that people complain about, though, tend to be fatigue and blood count changes."

It's important that you share any and all side effects with your doctor. You may be able to adjust your dosage or switch to another PARP inhibitor to reduce or eliminate side effects.

Partner with your health care team to know whether you qualify for this type of treatment. Don't hesitate to ask questions about the benefits and risks of PARP inhibitors, as well as any potential side effects that you might experience. Together with your doctor, you can develop the right treatment plan for you.

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