PARP Inhibitors Improve Survival Rate in Some Relapsed Ovarian Cancer Patients

Most women with advanced cases of ovarian cancer will mostly like see the disease return. The recurrence of cancer can be aggressive and potentially be fatal.

A new study, presented at the 2020 American Society of Clinical Oncology meeting, shows a poly ADP-ribose polymerase (PARP) inhibitor called olaparib should be the standard maintenance therapy for patients with BRCA-related relapsed ovarian cancer.

The use of poly ADP-ribose polymerase (PARP) inhibitors has been explored by physicians and researchers as a way to prolong time without cancer recurring by using it as a maintenance treatment after chemotherapy. PARP inhibitors are a targeted therapy that block a protein that helps repair DNA when it becomes damaged. This can keep cancer cells from repairing themselves once they’ve had DNA damage - which can occur normally or from chemotherapy - resulting in cancer cell death.

The study, which included 196 women, showed:

• Olaparib extended overall survival by nearly 13 months, compared with a placebo, in women with platinum-sensitive relapsed ovarian cancer with BRCA 1 or 2 mutations
• At a five-year follow-up, 42.1% of women on the PARP inhibitor were alive, compared to 33.2% on the placebo.

"PARP inhibitors have radically changed the options available to all patients with advanced ovarian cancer with unprecedented activity,” said Dr. Robert Wenham, chair and research director for Gynecologic Oncology at Moffitt Cancer Center. “We knew they could delay recurrence in patients and even be used by themselves to treat some patients, but we now have actual patients living longer."

Although the survival data for PARP inhibitors is for women with BRCA mutations, findings of delayed recurrence in patients without the mutations have also been noted. Researchers are continuing to examine PARP inhibitors in other groups. Many clinical trials are also testing new drug combinations that include PARP inhibitors.

Moffitt was one of the first medical institutions in the world to enroll patients in clinical trials evaluating the use of another PARP inhibitor, niraparib, for women with recurrent ovarian cancer. That therapy received U.S. Food and Drug Administration approval in March 2017.

Clinical Trial 20137 is an open-label, single-arm Phase 2 study to evaluate the efficacy and safety of the combination of niraparib and TSR-042 in patients with advanced, relapsed, high-grade ovarian, fallopian tube, or primary peritoneal cancer without a known BRCA mutation who have platinum-resistant disease and who have also been previously treated with bevacizumab.

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