FDA Approves Once-Daily PARP Inhibitor as First-Line Monotherapy for Ovarian Cancer

Niraparib (Zejula, GlaxoSmithKline) has been approved by the FDA as the only oral, once-daily poly ADP-ribose polymerase (PARP) inhibitor monotherapy for first-line maintenance treatment of patients with platinum-responsive ovarian cancer, regardless of BRCA mutational status.

Previously, the only women with ovarian cancer eligible to be treated with PARP inhibitors as monotherapy in the maintenance setting were those with a BRCA mutation. This group comprised approximately 20% of total patients with ovarian cancer, according to a GlaxoSmithKline press release.

“Women with advanced ovarian cancer have a 5-year survival rate of less than 50%,” said Hal Barron, MD, chief scientific officer and president of research and development at GlaxoSmithKline, in a statement. “This expanded indication means that many more women with this devastating disease can receive earlier treatment with Zejula, which can extend the time it takes for their cancer to progress.”

The approval is based on data from the phase 3 PRIMA study, comprised of patients with newly diagnosed advanced ovarian cancer following a complete or partial response to platinum-based chemotherapy regardless of biomarker status. Specifically, the PRIMA study enrolled women who had a higher risk of disease progression, which is a population with a high unmet need, according to the press release.

At initiation of the study, patients received a fixed starting dose of 300 mg of niraparib once daily. It was later amended to include an individualized starting dose of either 200 mg or 300 mg once daily, based on the patient’s baseline weight and/or platelet count.

The investigators observed lower rates of grade 3 and 4 hematologic treatment-emergent adverse events in the individualized starting dose, compared with the overall population. They observed thrombocytopenia in 21% and 39%, respectively; anemia in 23% and 31%, respectively; and neutropenia in 15% and 21%, respectively.

The primary endpoint was progression-free survival, which was analyzed first in the homologous recombination deficient (HRd) population and then in the overall population. In the HRd group, niraparib resulted in a 57% reduction in the risk of disease progression or death when compared with placebo. Similarly, it resulted in a 38% reduction among the overall population.

The safety profile was consistent with clinical trial experience. The most common grade 3 or higher events were thrombocytopenia (39%), anemia (31%), and neutropenia (21%).

“It’s so important for patients with ovarian cancer to have treatment options, and this approval is positive news for our community,” said Audra Moran, MA, president and CEO of the Ovarian Cancer Research Alliance, in a statement. “PARP inhibitors represent a major advancement in the fight against ovarian cancer, and having a new first-line maintenance option for platinum-responsive advanced ovarian cancer patients—regardless of BRCA mutation status—is especially exciting.”

REFERENCE

FDA approves Zejula (niraparib) as the only once-daily PARP inhibitor in first-line monotherapy maintenance treatment for women with platinum-responsive advanced ovarian cancer regardless of biomarker status [news release]. GlaxoSmithKline; April 29, 2020. https://www.gsk.com/en-gb/media/press-releases/fda-approves-parp-inhibitor-in-first-line-monotherapy-maintenance-treatment-for-women-with-platinum-responsive-advanced-ovarian-cancer-regardless-of-biomarker-status/. Accessed April 30, 2020.