GlaxoSmithKline (GSK) said that a phase 3 trial evaluating its polymerase (PARP) inhibitor Zejula (niraparib) as a maintenance therapy for first-line ovarian cancer following platinum-based chemotherapy, has met its primary endpoint.
Zejula achieved the primary endpoint of the PRIMA trial by showing a statistically significant improvement in progression-free survival irrespective of the participating women’s biomarker status, in comparison to placebo.
The safety and tolerability profile of the PARP inhibitor was in line with previous clinical trials, said GSK.
The PRIMA trial is a double-blind, randomised study that had enrolled first-line stage III or IV ovarian cancer patients. The study is assessing Zejula’s efficacy as maintenance treatment, as measured by progression-free survival.
In the late-stage trial, platinum responsive patients were randomly grouped 2:1 to the PARP inhibitor or placebo. The trial incorporated an individualised Zejula starting dose of 200mg once-daily in patients with baseline weight less than 77kg or platelet count less than 150K/μL and 300mg in all other patients.
GSK R&D chief scientific officer and president Hal Barron said: “Almost 300,000 women around the world are diagnosed with ovarian cancer every year, yet only about 15% of patients are currently eligible to receive PARP inhibitors as their initial therapy. These exciting data demonstrate that Zejula has the potential to significantly benefit even more women with this devastating cancer.”
In March 2017, Zejula was approved by the US Food and Drug Administration (FDA) for the treatment of women with recurrent ovarian cancer. The approval was given to Massachusetts-based oncology-focused company Tesaro, which was acquired by GSK for £4bn in January 2019.
Zejula is also approved in Europe as a treatment for adult women with recurrent ovarian cancer who are responsive to platinum-based chemotherapy, irrespective of BRCA mutation or biomarker status.
Last month, the PARP inhibitor secured priority review designation from the FDA for the treatment of late-stage ovarian cancer. The FDA has given an action date of 24 October 2019 to take a decision on the PARP inhibitor, which is backed by data from the phase 2 QUADRA trial.
In the mid-stage study, the drug showed activity in the primary efficacy population of fourth and fifth-line HRD positive patients who were PARP inhibitor naïve, and sensitive to platinum-based chemotherapy.