 This is a Phase 2, open-label, single arm study to evaluate progression free survival rate at 18 months as well as evaluating the safety and efficacy of niraparib in combination with bevacizumab as maintenance therapy in patients with advanced ovarian cancer patients who have received prior front-line therapy with platinum-based chemotherapy in combination with bevacizumab and who have had at least one prior attempt at debulking surgery. Niraparib is an orally active poly adenosine diphosphate-ribose PARP inhibitor. Niraparib will be administered by mouth once daily continuously during a 21-day cycle. Bevacizumab will be administered intravenously D1 of each 21-day cycle for up to 15 mos, including the duration of the front-line therapy. Health-related quality of life will be measured by Eastern Cooperative Oncology Group performance status ECOG. Safety and tolerability will be assessed by clinical review of adverse events AEs, physical examinations, electrocardiograms ECGs, RECIST tumor assessments and safety laboratory values. 