By Sara Bondell - May 30, 2020
After beating ovarian cancer, almost 70% of women will see her disease return. That number is even higher for the majority of women who have advanced cases and aggressive tumors. The recurrence may respond to additional chemotherapy, but it almost always recurs again and will eventually be fatal.
Physicians and researchers have been exploring the use of poly ADP-ribose polymerase (PARP) inhibitors to prolong time without cancer recurring by using it as a maintenance treatment after chemotherapy. PARP inhibitors are a type of 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.
A new study, which will be presented at this year’s American Society of Clinical Oncology annual meeting, confirms a PARP inhibitor called olaparib should be the standard maintenance therapy for patients with BRCA-related relapsed ovarian cancer.
The study’s results show 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. The study included 196 women, and 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.”
While the PARP inhibitor survival data is currently proven for women with BRCA mutations, there have also been findings of delayed recurrence in patients without the mutations. Researchers are continuing to examine PARP inhibitors in other groups, and there are many open clinical trials 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.