A Master Protocol Study to Investigate Biomarker-guided Novel Anticancer Agent(s) as Monotherapy or Combination Therapy in Participants With Advanced/Recurrent Ovarian Cancer

Key Inclusion Criteria: Master Protocol: 1. Participants who have histologically or cytologically documented advanced or recurrent epithelial ovarian, fallopian tube, or primary peritoneal cancer, considered to be suitable for treatment with study intervention, as applicable to each substudy. 2. Participants must provide sufficient archival or fresh tumour sample for biomarker testing. 3. Life expectancy at the time of screening ≥ 12 weeks in the opinion of the Investigator. 4. Measurable disease as per RECIST 1.1 criteria: at least one lesion that can be accurately measured at baseline as ≥ 10 mm in the longest diameter. 5. ECOG PS of 0 to 1, with no deterioration over the previous 2 weeks prior to baseline at screening, and prior to study intervention administration. 6. Adequate organ and marrow function. Substudy 1: 1. Participants must have histologically or cytologically confirmed newly diagnosed FIGO 2014 Stage III/IV epithelial ovarian\*, fallopian tube, or primary peritoneal cancer who are eligible for neoadjuvant treatment with planned IDS. 2. Participants who are treatment-naïve. 3. Participants with evidence of predicted loss of function tBRCA1/2m (by local testing) as assessed by a commercially available diagnostic test. Key Exclusion Criteria: Master Protocol: 1. Any history of persisting (\> 2 weeks) severe pancytopenia due to any cause (absolute neutrophil count \< 0.5 × 10/Liters (L) or platelets \< 50 × 10/L). 2. Spinal cord compression or brain metastases unless asymptomatic, treated, and stable and not requiring continuous corticosteroids prednisone/day or dexamethasone or equivalent for at least 4 weeks prior to start of study intervention. Participants with leptomeningeal carcinomatosis are excluded. 3. Active primary immunodeficiency/active infectious disease(s). 4. Participants with any known predisposition to bleeding (eg, active peptic ulceration, recent \[within 6 months\] haemorrhagic stroke, proliferative diabetic retinopathy). 5. Cardiac criteria, including history of arrhythmia and cardiovascular disease. 6. Prior malignancy that required treatment within 2 years prior to screening. 7. Previous allogeneic bone marrow or solid organ transplant. 8. As judged by the Investigator, any evidence of severe or uncontrolled systemic diseases or active uncontrolled infections. 9. Known allergy or hypersensitivity to investigational product(s) or any of the excipients of the investigational product(s) (as applicable to a substudy). 10. Concomitant use of drugs that are known to prolong or shorten QT and have a known risk of (Torsades de Pointes) TdP. 11. During the 4 weeks prior to the first dose, receiving continuous corticosteroids prednisone/day or equivalent for any reason. 12. Major surgical procedure (excluding placement of vascular access) or significant traumatic injury. 13. Any concurrent anticancer therapy. Substudy 1: 1. Participants with history of myelodysplastic syndrome (MDS) or acute myeloid leukaemia (AML) or with features suggestive of MDS/AML (as determined by prior diagnostic investigation). Specific screening for MDS/AML is not required. 2. Refractory nausea and vomiting, clinical signs or symptoms of Gastrointestinal (GI) obstruction and/or requirement for parenteral hydration or nutrition, history of prior intestinal obstruction, chronic GI diseases, inability to swallow the formulated product or previous significant bowel resection that would preclude adequate absorption of saruparib.