Ovarian Cancer

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Ovarian Cancer Treatment: PARP Inhibitors and Bevacizumab

Dr. Heidi Gray Seattle Cancer Care Alliance

PARP Inhibitors and Bevacizumab for Maintenance

  • A new two-drug combination was just approved by the FDA for ovarian cancer treatment
  • The drug combination consists of the PARP inhibitor olaparib and a targeted therapy (bevacizumab/Avastin)
  • PARP inhibitors may now be offered to almost all women regardless of genetic make-up

Doctors have more options to treat ovarian cancer than ever before. In fact, the Food and Drug Administration (FDA) has recently approved several new drugs for maintenance after chemotherapy to prevent future disease.

“The two main drug categories under investigation to help prevent disease recurrence include bevacizumab and PARP inhibitors,” says Dr. Heidi Gray, gynecologic oncologist at the Seattle Cancer Care Alliance.

Bevacizumab Explained

Scientists are exploring novel approaches that can be used in conjunction with traditional chemotherapy to help reduce the chance of a woman’s cancer recurring. One example: bevacizumab (brand name Avastin). Bevacizumab works by affecting the growth of blood vessels, starving tumors of the blood they need as nourishment.

“Bevacizumab was the first drug approved by the FDA as a maintenance therapy for ovarian cancer,” Dr. Gray says. Used in combination with chemotherapy, bevacizumab helps reduce the volume of disease so doctors can surgically remove any remaining disease in the abdominal cavity without damaging healthy vital structures — and it’s especially effective for women with advanced disease.

Since bevacizumab’s approval, the FDA has also approved another class of drugs, called PARP inhibitors, both for the primary treatment of ovarian cancer and in the maintenance setting.

Introducing PARP Inhibitors

After initial surgery and chemotherapy, studies suggest that PARP inhibitors may help reduce the odds that a cancer will recur. These unique drugs block the body’s natural DNA repair mechanisms so cancerous cells are unable to divide and thrive. In fact, studies suggest that using PARP inhibitors significantly extends the length of time until cancer recurs or worsens.

There are two different PARP inhibitors that are now FDA-approved for maintenance therapy in ovarian cancer:

Your doctor will recommend the appropriate drug based on the genetics of your tumor and other details about your health and disease. Both of the approved drugs have been shown to be effective at prolonging the time until the cancer comes back.

“Originally, the focus was on PARP inhibitors among women who have BRCA1 or BRCA2 mutations because the PARP inhibitors work better in that population,” Dr. Gray says. But recent studies show there is still a benefit to using PARP inhibitors for almost every ovarian cancer patient, regardless of whether she carries a BRCA mutation.

Most recently, the American Society of Clinical Oncology (ASCO) released new guidelines recommending 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.

Common Side Effects of PARP Inhibitors

Unfortunately, like all cancer therapies, PARP inhibitors come with side effects. Whether or not you’ll experience significant side effects from PARP inhibitors depends on several factors, including which PARP inhibitor you’re taking, what dose you’re ingesting, and whether you’re using it alone or in combination with other therapies.

Still, the side effects of most PARP inhibitor protocols include:

  • Nausea
  • Vomiting
  • Stomach upset
  • Fatigue

These side effects can be intolerable for some patients, but in almost every case, doctors can offer options to alleviate or even eliminate them. A few possibilities:

  • Discontinue treatment for a brief time period
  • Reduce the dose
  • Transition to another PARP inhibitor to see if there’s improvement

While most patients with ovarian cancer should have the option to try a PARP inhibitor, those who respond best tend to have high-grade disease, meaning the cancer is rapidly growing. Patients with low-grade disease may benefit from other categories of drugs, such as enzyme inhibitors or hormonal treatments.

No matter which category you fall into, it’s important to talk to your doctor about all available treatment options so you can make an informed decision. Ovarian cancer treatment is complex, but doctors have more tools at their disposal than ever before.


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Dr. Heidi Gray is a gynecologic oncologist at the Seattle Cancer Care Alliance. Read More

PARP Inhibitors for Ovarian Cancer

More woman than ever before are now able to use PARP inhibitors as part of their ovarian cancer treatment. The relatively new class of drugs show a lot of promise, but there are potential side effects women should be aware of.