WoO: Window of Opportunity Trial of Olaparib and Durvalumab in Histologically Proven EOC

In total, 60 patients are planned to be enrolled in 2 consecutive cohorts (30 patients per cohort) into the trial. After histologic confirmation of high-grade epithelial non-mucinous, non-clear cell ovarian cancer, patients will be treated in two consecutive cohorts (A, B) of 30 patients each, with A) olaparib alone or B) olaparib in combination with durvalumab Treatment allocation will take place in two consecutive cohorts rather than by randomization. This will allow to evaluate the safety and feasibility in a stepwise approach. A trial steering committee (TSC) meeting will take place between the cohorts to review safety and feasibility prior to starting the second cohort. The safety follow-up of the first cohort will take 90 days as of the first dose of therapy. Post chemo maintenance: After completion of first-line chemotherapy patients who have not progressed during first-line chemotherapy will receive the indicated standard maintenance treatment according to the national S3-guideline and treating physician's choice. For patients who have received all possible licensed treatment regimens according to the national guideline or for whom further licensed treatment options are unavailable or contraindicated, Olaparib may be offered as investigational maintenance therapy for up to 24 months. In cohort B, patients will be offered Durvalumab as an investigational therapy in combination with Standard of Care (SoC) chemotherapy and Bevacizumab, followed by a Durvalumab maintenance therapy for a total of 24 months as an investigational therapy in combination with SoC Bevacizumab and Olaparib. Patients for whom the choice of maintenance therapy is Niraparib or who don´t receive Bevacizumab cannot receive Durvalumab maintenance in combination unless they have a contraindication to Bevacizumab, in which case Durvalumab can be offered in combination with SoC chemotherapy and as maintenance therapy in combination with Olaparib. In HRD-negative patients who are selected to receive Bevacizumab maintenance, both Olaparib and Durvalumab will be investigational agents. In HRD-positive patients who are selected to receive Bevacizumab and Olaparib, only Durvalumab will be an investigational agent. The data supporting the rationale and also safety of the combination of Durvalumab, Bevacizumab and Olaparib are based on the randomized, placebo-controlled phase III AGO-OVAR 23/DUO-O study.