A Study to Examine Olaparib Maintenance Retreatment in Patients With Epithelial Ovarian Cancer.

The OReO study will investigate the efficacy and safety of Olaparib maintenance re-treatment in patients with relapsed non-mucinous EOC, who have had disease progression following maintenance therapy with a Polyadenosine 5'diphosphoribose \[poly (ADP ribose)\] polymerisation inhibitor (PARPi) and a complete or partial radiological response to subsequent treatment with platinum-based chemotherapy or may have no evidence of disease (if optimal cytoreductive surgery was conducted prior to chemotherapy), and no evidence of a rising CA-125. Patients will be enrolled on the basis of their breast cancer susceptibility gene (BRCA1, BRCA2) status into one of two cohorts (BRCA1/2 \[+ve\] and BRCA1/2 \[-ve\]). The BRCA1/2 (+ve) and BRCA1/2 (-ve) cohorts will be randomised separately. Within each cohort, patients will be randomised by prospective allocation in a 2:1 ratio (Olaparib: matching placebo).