Using PARP Inhibitors
- Zejula is approved for ovarian cancer patients, regardless of BRCA status, who show a response to first-line platinum-based chemotherapy.
- Some doctors say almost all women should be offered the new treatment.
- Response is much greater in women with BRCA mutations and positive HRD status (a molecular measure that predicts PARP effectiveness).
- There is, on average, a few month of benefit for women without BRCA mutations or positive “HRD” status.
The FDA’s Approval of Niraparib
"This is a much anticipated change in the upfront treatment of patients with advanced ovarian cancer. Giving patients an option for front line maintenance that may delay recurrence and improve survival from their cancer is exciting. As with all cancer-related treatment, it will be important to incorporate counseling about the risks and benefits of PARP inhibitor maintenance, and help patients understand their individual likelihood of benefit given their germline genetic and tumor characteristics. Helping educate our patients about the complexity of the tumor-directed treatment options will allow patients and their families to make the best health-related decisions for their lives and circumstances," Dr. Amanika Kumar, a gynecologic oncologist at Mayo Clinic, tells SurvivorNet.
Read MoreHow Is Niraparib Different?
The niraparib approval is not limited to women with a BRCA mutation, in contrast to FDA approvals for other PARP inhibitors. Therefore, the genetics of the patient and their tumor’s biology does not restrict them from receiving this treatment. The other PARP inhibitor currently available for maintenance treatment, olaparib (LYNPARZA), is approved for patients with deleterious or suspected deleterious germline BRCA mutations. 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. All women won’t get the same benefit from a PARP inhibitor. Patients with homologous recombination deficiency or BRCA mutations have far better responses than those without them.“To me, it is on us as clinicians to help patients understand the risk vs benefit of treatmentfor example, patients who have no mutation or HRD [homologous recombination deficiency] may choose not to go on maintenance (in fact I recommend they don't) because there is real toxicity to these medications,” explains Dr. Kumar to SurvivorNet.
Her sentiments are echoed by other physicians like Dr. Rebecca Arend at the University of Alabama, who told SurvivorNet that she will continue to prescribe on a case by case basis.
In recent trials, many women given niraparib have demonstrated some semblance of benefit in terms of time to recurrence, but this differs based on the genetic characteristics of the tumor. A BRCA mutation or HRD deficiency will indicate a much stronger response to PARP inhibitors. Side effects include a decrease in platelets and hemoglobin, but doctors can adjust doses to lessen the toxicity of the drug.
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