The Current and Future Landscape of PARP Inhibitors for Ovarian Cancer

Casey M. Cosgrove, MD

In recent years, PARP inhibitors have drastically changed the treatment landscape of patients with ovarian cancer. However, there are still unanswered questions and special considerations when prescribing patients with these agents, explained Casey M. Cosgrove, MD.

Cosgrove, a gynecologic oncologist at The Ohio State University Comprehensive Cancer Center— Arthur G. James Cancer Hospital and Richard J. Solove Research Institute, recently spoke with OncLive®, a sister publication of Oncology Nursing News®, about the evolving use of these drugs.

“All the PARP inhibitors have shown excellent efficacy. While we can't compare 1 trial to the other, I do think that we can confidently say, ‘All of them work really well for our patients,’” he said.

Choosing Between PARP Inhibitors

And while all 3 PARP inhibitors — niraparib (Zejula), olaparib (Lynparza), and rucaparib (Rubraca) – are approved in the maintenance setting, clinicians should think about the adverse event (AE) profile to help decide which agent patients should get.

“Some of the AEs are important [to take into consideration],” Cosgrove said. “Some of [the PARP inhibitors] have increased bone marrow toxicity or are more likely to cause bone marrow suppression. For a patient who may be at higher risk for that, I might opt for [a PARP inhibitor] with [lower] bone marrow toxicity.

Some agents may also have heightened risk for gastrointestinal (GI) toxicity. So, if a patient already has nausea before starting the agent, she should get a PARP inhibitor with a lower GI toxicity profile.

“At the end of the day, it's a discussion with the patient, seeing what they're comfortable with, and going over each [option]. All of these agents end up being an excellent option at the end of the day,” Cosgrove said.

Next Steps and Unanswered Questions

While more patients have been getting PARP inhibitors in the maintenance setting, now the question is: What happens when they experience disease recurrence? Cosgrove asked if they could be retreated with a PARP inhibitor and if it would still be effective.

This question is currently being evaluated in the OReO trial, a randomized, double-blind, phase IIIb trial that is investigating the efficacy of retreating patients with olaparib who have epithelial ovarian cancer. The trial is being conducted in the maintenance setting, after patients have received chemotherapy.

“When the cancer comes back, they get treated again with platinum-based chemotherapy and then get put on olaparib or placebo. This will give us an idea as to whether we can use a PARP inhibitor after another PARP inhibitor. That's going to be the biggest question moving forward with ovarian cancer management,” Cosgrove said.

A version of this article originally appeared on OncLive as, “More Research Must Focus on Later-Line Therapies in Ovarian Cancer.”