Efficacy & Safety of Olvi-Vec and Platinum-doublet + Bevacizumab Compared to Physician's Choice of Chemotherapy and Bevacizumab in Platinum-Resistant/Refractory Ovarian Cancer (PRROC) (OnPrime, GOG-3076)

Inclusion Criteria:

* Histologically confirmed (from prior treatment) non-resectable ovarian, fallopian tube or primary peritoneal cancer.
* High-grade serous \[including malignant mixed Mullerian tumor (MMMT) with metastasis that contains high-grade epithelial carcinoma, FIGO grades 2 \& 3 allowed\], endometrioid, or clear-cell ovarian cancer.
* Performance status ECOG of 0 or 1.
* Life expectancy of at least 6 months.
* Received a minimum of 3 prior lines (including the 1st line) of systemic therapy with no maximal limit.
* Platinum-resistant or -refractory disease based on platinum-free interval (PFI) from the last dose of the most recent. platinum-based line of therapy (must have received a minimum of 2 doses of platinum in that line) to subsequent disease progression based on radiological assessment. Platinum-refractory: PFI of \< 1 month (including disease progression while on platinum-based therapy). Platinum-resistant: PFI of 1-6 months.
* Received prior bevacizumab (or biosimilar) treatment.
* No contraindication to receive carboplatin, cisplatin or bevacizumab (or biosimilar).
* Have disease progression after last prior line of therapy based on radiological assessment prior to randomization.
* At least 1 measurable target lesion per RECIST 1.1 based on abdominal/pelvis imaging scan at screening.
* Evidence by CT and/or PET scans or physical exam of abdominal/pelvis region likely having disease in the peritoneal cavity (i.e., peritoneal carcinomatosis).
* Adequate renal, hepatic, bone marrow function, adequate coagulation tests, adequate immune function by lymphocyte count.

Exclusion Criteria:

* Tumors of mucinous, low-grade serous, squamous cell, small cell neuroendocrine subtypes, MMMT tumors absent an epithelial component on recent biopsy, or non-epithelial ovarian cancers (e.g., germ cell tumors, Sex-cord tumors).
* Bowel obstruction within last 3 months prior to screening.
* Active urinary tract infection, pneumonia, other systemic infections.
* Active gastrointestinal bleeding.
* Known current central nervous system (CNS) metastasis.
* Inflammatory diseases of the bowel.
* History of HIV infection.
* Active hepatitis B virus or hepatitis C virus within 4 weeks prior to study.
* History of thromboembolic event within the prior 3 months.
* Contraindications for intraperitoneal (IP) catheter placement: Bowel obstruction with distended abdomen, rigid abdomen with bulky anterior wall carcinomatosis, abdominal wall hernia mesh that precludes laparoscopic entry to abdomen.
* Clinically significant cardiac disease at screening (New York Heart Association Class III/IV).
* Acute cerebrovascular event(s) such as cerebrovascular accident (CVA) or transient ischemic attack (TIA) in previous 6 months.
* Oxygen saturation \<90%.
* Received prior virus-based gene therapy or therapy with cytolytic virus of any type.
* Receiving concurrent antiviral agent.
* Prior malignancy of other histology active within previous 3 years except for locally curable cancers apparently cured such as basal/squamous cell skin cancer, superficial bladder cancer, carcinoma in situ of cervix or breast, any other stage I/II local malignancies.
* Received chemotherapy, radiotherapy, other anti-cancer biologic therapies within 4 weeks prior to planned treatment.
* Underwent surgery within 4 weeks, or have insufficient recovery from surgical-related trauma or wound healing, prior to first study treatment in either Arm.
* Receiving immunosuppressive therapy or steroids (except acute concurrent corticosteroid of no more than 20 mg per day for medical management with prednisolone equivalent.
* Symptomatic malignant ascites or pleural effusions defined as rapidly progressive ascites with abdominal distension and gastrointestinal dysfunction, pleural effusions with respiratory difficulties requiring frequent paracentesis \> once every 14 days.
* Known hypersensitivity to gentamicin.