Trial of THEO-260 in Ovarian Cancer Patients

Inclusion Criteria: * Confirmed histological diagnosis of advanced high grade serous or endometrioid cancer of the fallopian tube, primary peritoneum or ovary either on archival biopsy or fresh tumour biopsy. * Platinum-resistant disease (radiological recurrence/ progression with 6 months of prior platinum treatment), primary platinum-refractory disease (recurrence/ progression during first line platinum treatment) and patients who are intolerant to or have no available SOC or SOC unacceptable/ unsuitable in the view of the Investigator. * Life expectancy of \> 3 months. * ECOG performance status of 0 or 1. * Measurable disease as per RECIST V1.1. Exclusion Criteria: * Prior anti-cancer treatment within 28 days or 5 half-lives, prior to first dose of THEO-260. * Prior treatment with a group B adenovirus. * Currently enrolled in a clinical trial of an IMP or used any IMP with 5 half-live, prior to first dose of THEO-260. * Radiation therapy within 2 weeks of first dose of THEO-260 and is scheduled to have radiation therapy during participation of trial. * Clinical evidence of cerebral metastases or Central Nervous System (CNS) involvement including leptomeningeal disease. Patients with previous cerebral metastases must have no evidence of progression or haemorrhage after treatment. * Uncontrolled pleural effusion or pericardial effusion requiring recurrent drainage procedures (as defined as once monthly or more frequently). * Prior pneumonitis or history of interstitial lung disease. * Confirmed QTcF ≥470 ms on screening 12-lead ECG or history of Torsades de Pointes or history of congenital long QT syndrome. * Concomitant medications that prolong the QTc interval and/or increase the risk for Torsades de Pointes. * Patients with active hepatitis infection or hepatitis C. Patients with past hepatitis B virus (HBV) infection or resolved HBV infection. * Active infection with tuberculosis. * Active infection with severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2). * Patients with active human immunodeficiency virus (HIV) infection or known history of HIV infection. * Active infection requiring IV antibiotics within 2 weeks prior to first dose of THEO-260, or long-term oral therapy for systemic infection. * Known contra-indications or hypersensitivity to the excipients of the IMP. * Viral infection during the 2 weeks prior to first dose of THEO-260. * Active autoimmune disease that has required systemic treatment in the past 2 years. * Known risk of renal injury, including those with a past history of acute or sub-acute renal disease. * Known heart failure New York Heart Association (NYHA) Class 2-4. * Known contra-indications or hypersensitivity to the AxMP, paracetamol. * Known alcohol consumption in excess of 2 units per day. * Left ventricular ejection fraction (LVEF) \<50%, unstable angina, serious uncontrolled cardiac arrhythmia, a myocardial infarction within 6 months prior to trial enrolment or a history of myocarditis. * Arterial oxygen saturation \<92% on room air prior to first dose of THEO-260. * Received any licensed or investigational vaccines within 28 days prior to first dose of THEO-260.