Discussant of the PRIME trial, Barbara S. Norquist, MD, Associate Professor of Obstetrics and Gynecology at the University of Washington, Seattle, noted that although all subgroups in the PRIMA study appeared to derive benefit from niraparib maintenance therapy, patients with homologous recombination–proficient (HRP) disease did not have the same magnitude of benefit as those with homologous recombination–deficient (HRD) disease.

Barbara S. Norquist, MD

“In the PRIME study, however, the HRD assay was not helpful in predicting response,” said Dr. Norquist. “This may have been because of the different starting dose used, the different HRD assay, or the very young population studied.”

Dr. Norquist continued: “The PRIME study also allowed complete resection, whereas patients enrolled on PRIMA had to have residual disease or stage IV disease or had to have received neoadjuvant chemotherapy. A significant proportion of patients in the PRIMA trial had BRCA mutations, too.”

According to Dr. Norquist, the optimal measurement strategy for detecting HRD remains unknown, but more data are accumulating.

“The substantial financial and physical toxicities of targeted therapies are important, and we need predictive biomarkers to optimize patient selection,” Dr. Norquist concluded. “In addition, we must expand access to clinical trials, molecular testing, and targeted therapies, so all may participate in the promise of personalized medicine.” 

DISCLOSURE: Dr. Norquist reported no conflicts of interest.