Ovarian cancer specialists in Portland, around the country, are increasingly excited about the new treatment possibility of PARP inhibitors, and one reason is that more and more research is finding that there is some benefit for many different kinds of patients.
How PARP Inhibitors Work
PARP inhibitors interrupt the process of single stranded DNA repair, an essential part of cell replication. Defects in DNA repair ultimately cause cell death. For the regular person just trying to understand their options, keeping cancer cells from making copies of themselves helps shrink the disease, or at least keep it at bay.
Genetic Testing is Crucial
Read More- Experts tell SurvivorNet that every woman with ovarian cancer should get a genetic test to determine if they have a mutation called BRCA, because the mutation enables PARP inhibitors to function much more powerfully. Importantly, there is increasing data that even women without BRCA mutations can still derive some benefit from these drugs.
- Some doctors are still getting comfortable with PARP inhibitors, and because the research is developing so quickly, your genetic makeup and the stage of your cancer may well make you a potential candidate.
Who Can Use PARP Inhibitors & What Are the Current Approvals & Indications?
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.The PARP inhibitor Zejula (niraparib) has been approved by the FDA for all women with newly diagnosed ovarian cancer irrespective of whether the tumor is positive, or proficient, for homologous recombination deficiencies (HRD). The drug is used after successful treatment with a platinum-based chemotherapy, the mainstay chemotherapy for ovarian cancer.
Ovarian cancer patients with a lot of homologous recombination deficiencies exhibit specific clinical behaviors, and improved responses to treatments, such as platinum-based chemotherapy and PARP inhibitors, according to researchers.
Due to limited benefit in progression free survival seen in the absence of HRD, gynecologic oncologists differ on whether PARP inhibitors should be universally recommended in the "upfront maintenance setting." Each patient should be made aware of risks and benefits to PARP inhibitor maintenance and decide with their oncologist what is the best treatment plan for them.
The PARP inhibitor Lynparza (olaparib) is approved for women newly diagnosed with ovarian cancer and with a germline or somatic mutation in BRCA1/2.
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.
Using PARPs to Treat Recurrence
Unfortunately, too often, ovarian cancer comes back.
For women with ovarian cancer who have had a recurrence and responded to platinum-based chemotherapy, Lynparza, Zejula and another PARP inhibitor called Rubraca (rucaparib) are FDA approved for use as a maintenance therapy, regardless of whether a woman has a BRCA mutation or HRD.
For some women who have had prior chemotherapy treatments, Rubraca, Zejula or Lynparza may also be options. These uses are based on factors such as number of prior therapies and BRCA mutation or HRD.
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