GlaxoSmithKline's Zejula improves progression-free survival as maintenance therapy in first-line ovarian cancer

GlaxoSmithKline said Monday that a Phase III study of Zejula (niraparib) as a maintenance therapy in patients with first-line ovarian cancer following platinum-based chemotherapy met its primary endpoint. Results of the PRIMA trial showed that the oral, once-daily PARP inhibitor significantly improved progression-free survival versus placebo in women regardless of their biomarker status.

The study randomised first-line Stage III or IV ovarian cancer patients to receive Zejula or placebo as maintenance treatment. GlaxoSmithKline noted that the safety and tolerability profile of the drug was consistent with previous clinical trials, while full results will be presented at an upcoming medical meeting.

GlaxoSmithKline gained Zejula as part of its $5.1-billion purchase of Tesaro earlier this year. "Zejula's potential to expand PARP use beyond BRCAm (BRCA mutation) patients, was a key justification for its Tesaro acquisition and this required a positive outcome for Zejula in the PRIMA study," Jefferies analysts said, adding that peak sales for the product in this indication are $550 million.

The drug is currently approved in the US and Europe as a treatment for adults with recurrent ovarian cancer who are in response to platinum-based chemotherapy, regardless of BRCA mutation or biomarker status. Zejula is also being studied for the treatment of triple-negative breast cancer, while Johnson & Johnson's Janssen Biotech unit has rights to develop the therapy for patients with prostate cancer worldwide, except in Japan.

Last year, AstraZeneca and Merck & Co. reported detailed results from the Phase III SOLO-1 trial, showing that two-year maintenance therapy with the PARP inhibitor Lynparza (olaparib) led to a 70% reduction in the risk of progression or death versus placebo in newly diagnosed patients with advanced ovarian cancer and a BRCA1 or 2 mutation.

For related analysis, see ViewPoints: GlaxoSmithKline's push back into oncology gets a lift in the right direction.

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