After Recurrence: PARP Inhibitors Can Improve Ovarian Cancer Survival Rates

Without the drugs, after 14 months patients with a BRCA mutation have a 50% chance of the cancer coming back. “But when patients who had completed chemotherapy added a two-year course of the PARP inhibitor, Lynparza (olaparib), the chance of the cancer not coming back improves significantly,” he says.

“If she takes Lynparza,” Dr. Hanna explains, “about 55% of the patients have been without cancer recurrence for four years after the completion of chemotherapy.”

Cancer that recurs six months or more after the initial chemotherapy is called “platinum sensitive.”  In this case, Dr. Hanna says, “if you give them chemotherapy with a platinum-containing regimen, and if they have a complete or partial response, you can use any of the PARP inhibitors,” he notes.

“We also have indications for PARP inhibition if the cancer has a BRCA mutation.”

While initially, women with a BRCA-1 or BRCA-2 genetic mutation had been shown to respond especially well to PARP inhibitors after recurrence, newer research has shown that women with the BRCA gene mutation (and indeed almost all women), can consider using PARP inhibitors throughout their treatment.

The Food and Drug Administration has approved Zejula (niraparib) for almost all women regardless of whether they have the BRCA mutation, as part of an initial course of treatment, or what’s called front-line treatment.

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.

However, 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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