• Signed informed consent obtained prior to initiation of any study-specific procedures.

• Female aged≥18 years old on day of signing informed consent.

• Patients with histologically diagnosed advanced stage III-IV according International Federation of Gynaecology and Obstetrics (FIGO), high grade serous or endometrioid, epithelial ovarian cancer (including primary peritoneal or fallopian tube cancer).

• Patients with a complete or partial response to first line platinum-based treatment not including Bevacizumab.

• Documented absence of somatic and germline mutations of BRCA 1 /2.

• Patients must have a life expectancy ≥ 16 weeks.

• Eastern Cooperative Oncology Group (ECOG) Performance Status of 0 to 1, (See Appendix A).

• Availability of sufficient formalin-fixed paraffin-embedded (FFPE) tumor tissue from the primary surgery (chemotherapy - naïve patients) for translational analysis. A quality control analysis of samples will be performed before patient's enrollment.

• Patients must be enrolled within 8 weeks of the first day of the last dose of chemotherapy.

⁃ Patients must be able to take oral medications.

⁃ Postmenopausal or evidence of non-childbearing status for women of childbearing potential: negative urine or serum pregnancy test within 28 days of study treatment and confirmed prior to treatment on Day 1 Cycle 1.

⁃ Postmenopausal is defined as:

‣ Amenorrheic for 1 year or more following cessation of exogenous hormonal treatments;

‣ Luteinizing hormone (LH) and Follicle stimulating hormone (FSH) levels in the post-menopausal range for women under 50;

‣ radiation-induced oophorectomy with last menses \>1 year ago;

‣ chemotherapy-induced menopause with \>1 year interval since last menses;

‣ surgical sterilisation (bilateral oophorectomy or hysterectomy).

⁃ Women Women of childbearing potential and their partners, who are sexually active, must agree to the use of one highly effective forms of contraception and their partners must use a male condom (as described in Appendix D). This should be started from the signing of the informed consent and continue throughout the period of taking study treatment and for at least 1 month after last dose of study drug

⁃ Patients must have normal organ and bone marrow function measured within 28 days prior to administration of study treatment as defined below:

⁃ Haemoglobin ≥ 10.0 g/dL with no blood transfusion in the past 28 days; Absolute neutrophil count (ANC) ≥ 1.5 x 109/L; Platelet count ≥ 100 x 109/L; Total bilirubin ≤ 1.5 x institutional upper limit of normal (ULN); Aspartate aminotransferase (AST) (Serum Glutamic Oxaloacetic Transaminase (SGOT)) / Alanine aminotransferase (ALT) (Serum Glutamic Pyruvate Transaminase (SGPT)) ≤ 2.5 x institutional upper limit of normal unless liver metastases are present in which case they must be ≤ 5x ULN

⁃ Patients must have creatinine clearance estimated of ≥51 mL/min using the Cockcroft-Gault equation or based on a 24-hour urine test:

‣ Estimated creatinine clearance = (140-age \[years\]) x weight (kg) (x F) a

‣ serum creatinine (mg/dL) x 72 a where F=0.85 for females

⁃ Willingness and ability to comply with scheduled visits, treatment plan, laboratory tests, and other trial procedures.