Background: Multiple Phase 1 and 2 clinical studies of PARP inhibitors used as monotherapy to treat patients with recurrent ovarian cancer (ROC) suggest that the agents are active in this population and there is level one evidence that bevacizumab is beneficial In the same population. A phase two randomized study demonstrated that the addition of a PARP inhibitor to an anti-angiogenic drug cediranib improves Progression-free survival (PFS). Our aim is to compare tolerability and efficacy of niraparib alone versus niraparib-bevacizumab combination versus sequential bevacizumab and niraparib. Methods: The ENGOT-OV24-NSGO/AVANOVA study comprises of two parts. Part 1 is a classic phase 1 trial of niraparib and bevacizumab combination. Part 2 is a three-arm, open-label, phase II, 1:1:1 randomized study of niraparib and/or Niraparib-bevacizumab combination against bevacizumab followed by niraparib in women with platinum-sensitive ROC. BRCAmut and or high-grade serous/endometrioid carcinoma patients with platinum-sensitive ROC are eligible. Patients must have disease that is measurable according to RECIST or assessable according to the GCIG CA-125 criteria. Primary objective of phase 1 part is to evaluate the safety and tolerability of bevacizumab-niraparib combination therapy and determine the Recommended Phase 2 Dose (RP2D) of bevacizumab-niraparib. Primary objective of phase 2 part is to obtain preliminary evidence of efficacy of bevacizumab- niraparib combination or sequential therapy or niraparib single agent treatment. Primary end-point is PFS. Secondary end-points include PFS in each group according to trial stratification factors; PFS comparison of sequential versus concomitant bevacizumab and Niraparib; Objective response rate; Disease control rate (DCR); Patient Reported Outcomes (PROs); Time to subsequent chemotherapy and survival. Study status: The study is activated and sites are invited to participate. ClinicalTrials.gov Identifier: NCT02354131 Clinical trial information: NCT02354131