Study results presented at the Society of Gynecologic Oncology (SGO) annual meeting showed that AstraZeneca's PARP inhibitor Lynparza (olaparib) significantly improved progression-free survival (PFS) in certain patients with BRCA-mutated ovarian cancer, compared with placebo in the maintenance setting, the company announced Tuesday. Chief medical officer Sean Bohen said AstraZeneca is "extremely pleased with the results from SOLO-2, which support the potential benefit of Lynparza tablets as a maintenance therapy for patients with relapsed ovarian cancer."

The SOLO-2 trial enrolled 295 patients with germline, BRCA-mutated, relapsed ovarian cancer who entered the study having achieved a complete or partial tumour response to platinum-based chemotherapy. Patients were then randomised to receive Lynparza tablets twice-daily or a placebo as maintenance therapy.

AstraZeneca stated that the trial met its primary endpoint of investigator-assessed PFS, with Lynparza-treated patients achieving a median PFS of 19.1 months, versus 5.5 months for placebo. When disease progression was measured by central blinded review, PFS in the Lynparza group rose to 30.2 months. Further, a significant benefit in time to second progression or death was also seen in patients treated with Lynparza, as well as improvements in other key secondary endpoints, the company added.

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Meanwhile, the safety profile for patients treated with Lynparza "was generally consistent to those observed with the currently-approved capsule formulation," the drugmaker noted, with the most common haematological adverse events being anaemia, neutropaenia and thrombocytopaenia. Bohen indicated that the company would work with regulatory authorities to make the tablet formulation of Lynparza "available to patients as quickly as possible."

Lynparza was approved in the US in 2014 for patients with germline BRCA-mutated advanced ovarian cancer treated with three or more prior lines of chemotherapy. AstraZeneca is seeking to expand the drug's label in the US to include maintenance therapy for ovarian cancer, but has not offered a timetable for when the data will be submitted to the FDA. In Europe, Lynparza is approved for the maintenance treatment of adults with relapsed BRCA-mutated ovarian, fallopian tube, or primary peritoneal cancer who are in complete response or partial response to platinum-based chemotherapy.

Shares in Tesaro, which also presented Phase III data on its experimental PARP inhibitor niraparib at the SGO meeting, were down 13 percent on Tuesday. The company has already submitted a filing for niraparib to the FDA, with a decision expected by June 30, and has also applied to European regulators. Meanwhile shares in Clovis Oncology, which recently gained accelerated FDA approval for its PARP inhibitor Rubraca (rucaparib) to treat BRCA-mutated advanced ovarian cancer in women who previously received two or more chemotherapies, rose more than 7 percent.