New PARP Inhibitor Approvals
- Niraparib is available for almost all women for the treatment of ovarian cancer, regardless of BRCA mutations
- The response is much greater in women with BRCA mutations and positive HRD status (a molecular measure that predicts PARP effectiveness)
- PARP inhibitors have toxicities that create very real side effects that need to be monitored and discussed with your doctor
PARP inhibitors are available to almost all women, though women with BRCA gene mutations or who are HRD proficient may benefit the most from these drugs. However, 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.
Read More- Niraparib (Zejula)
- Olaparib (Lynparza)
- Rucaparib (Rubraca)
- 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 HRD. The drug is used after successful treatment with a platinum-based chemotherapy, the mainstay chemotherapy for ovarian cancer.
- 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.
Current Approvals Using PARPs To Treat Recurrence
- 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.
Risk Vs. Benefit
Again, many specialists caution that the benefit is extremely limited for women without the optimal molecular characteristics in their cancer. Being a good candidate for these drugs is only one factor to take into consideration when making the decision about whether you should take PARP inhibitors. It's also important to weigh the potential benefits of treatment against possible side effects like nausea, vomiting, fatigue, and a drop in blood cell counts. These side effects can be severe and have an impact on your quality of life so it is important to discuss the treatment strategy with your doctor.
Dr. Amanika Kumar of the Mayo Clinic who spoke to SurvivorNet, cautioned that women still need to speak with their doctor to evaluate the benefit of taking a PARP inhibitor to extend life, because there are very real side effects due to the toxicity of the drug. "Patients with HRD (homologous recombination deficiency) have a far better response than those without and those with BRCA mutations even more so. It is on us as clinicians to help patients understand the risks and benefits of treatment. Patients that have no mutation or HRD may choose not to go on maintenance (in fact I recommend they don't) because there is real toxicity to these meds."
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