Clinical Trials Investigating PARP Inhibitors in Prostate Cancer

Maha H. Hussain, MB, ChB, professor of medicine and deputy director at Robert H. Lurie Comprehensive Cancer Center, discusses the current role of PARP inhibitors in clinical trials for treatment of patients with prostate cancer.

At her institution, Hussain is leading a clinical trial investigating the use of either abiraterone acetate (Zytiga), olaparib (Lynparza), or a combination of the 2, in patients preselected for DNA repair defect. Hussain says we are currently in an era of constant discovery of different alterations in the DNA repair pathway, leading investigators to question if they are as relevant as BRCA 1/2, or ATM.

In preclinical trials, results appear unclear in terms of responsiveness. Hussain refers to this as “shades of gray.” In other trials, 5 different PARP inhibitors are being evaluated as well. There are several phase III trials investigating these agents in both preselected and not preselected trials, Hussain adds.

PARP inhibitors are also being examined in combinations as well, with a variety of different agents. Hussain says these combinations include immune checkpoint inhibitors, radium, VEGF inhibitors, and platinum-based agents. Single-agent PARP inhibitors are also being investigating in hormone-sensitive populations. Hussain hopes that in the next few years, we will have the answers.