Phase I / II Study of Enadenotucirev by Sub-acute Fractionated IV Dosing in Cancer Patients

Inclusion Criteria: * Patients must provide written informed consent * Age ≥ 18 years and the patient must be at least the legal age limit to be able to give consent within the jurisdiction the study is taking place. * ECOG performance status 0 or 1 * Predicted life expectancy of 3 months or more * Ability to comply with study procedures in the Investigator's opinion * Recovered to Grade 1 from the effects (excluding alopecia) of any prior therapy for their malignancies * Adequate renal function * Creatinine ≤ 1.5 mg/dL or calculated creatinine clearance using the Cockcroft-Gault formula ≥ 60 mL/min, or measured creatinine clearance ≥ 60 mL/min, Haematuria: dipstick ≤ 2+ * Proteinuria: dipstick ≤ 2+ * Adequate hepatic function * Serum bilirubin \< 1.5 mg/dL * Aspartate transaminase (AST) and alanine transaminase (ALT) ≤ 3x upper limit of normal (ULN) * Adequate bone marrow function: * Absolute neutrophil count (ANC) ≥ 1.5 x 109/L * Platelets ≥ 100 x 109/L * Haemoglobin ≥ 100 g/L for UCC and ≥ 90 g/L for other cancers * Adequate coagulation tests: international normalised ratio (INR) ≤ 1.5 x ULN * For females of childbearing potential (defined as \<2 years after last menstruation or not surgically sterile), a negative serum pregnancy test must be documented within 14 days prior to first administration of study treatment * For women who are not postmenopausal (24 months of amenorrhea) or surgically sterile (absence of ovaries and/or uterus): agreement to use two adequate methods of contraception, during the treatment period and for at least 3 months after the last dose of study drug * For men: agreement to use a barrier method of contraception during the treatment period and for at least 6 months after the last dose of study drug * At least 3 weeks since any dose of IV systemic chemotherapy and at least two weeks since any oral dose of capecitabine at the time of first administration of ColoAd1. Phase I Specific Inclusion Criteria: Dose Escalation Stage only (except Repeat Cycle Cohort): \- Solid tumour of epithelial origin not responding to standard therapy or for whom no standard treatment exists Dose Expansion Stage Single Cycle and Dose Escalation Stage Repeat Cycle Cohort: * mCRC not responding to standard therapy * ≤ 3 prior lines of systemic therapy for advanced disease OR ≤ 4 prior lines of systemic therapy for advanced disease if one of the 4 lines was an anti EGFR therapy given as a single agent or combined to a previously administered chemotherapy regimen Phase Ib:mCRC not responding to standard therapy * no more than 3 prior lines of systemic therapy for advanced disease OR no more than 4 prior lines of systemic therapy for advanced disease if one of the 4 lines was an anti EGFR therapy given as a single agent or combined to a previously administered chemotherapy regimen * Advanced or metastatic UCC, who have received a maximum of one chemotherapy-containing regimen and a maximum of one other systemic treatment with biologic agents only. Phase II Specific Inclusion Criteria: * mCRC * Have received 3 - 4 months of first line chemotherapy with either FOLFOX, FOLFIRI or CAPOX, with or without bevacizumab * At least one measurable lesion according to RECIST 1.1 criteria * Documented partial response or stable disease * Eligible to receive chemotherapy with FOLFOX or CAPOX after a short chemotherapy interruption (3 to 4 weeks) Exclusion Criteria for all Patients: * Pregnant or breast feeding females; * Known history or evidence of significant immunodeficiency due to underlying illness (e.g. human immunodeficiency virus \[HIV\]/acquired immunodeficiency syndrome \[AIDS\]) and/or medication (e.g. systemic corticosteroids, or other immunosuppressive medications including cyclosporine, azathioprine, interferons, within the past 4 weeks) * Splenectomy * Prior allogeneic or autologous bone marrow or organ transplantation * Active infections requiring antibiotics, physician monitoring, or recurrent fevers \>38.0 degrees centigrade associated with a clinical diagnosis of active infection * Active viral disease or known positive serology for HIV, hepatitis B or hepatitis C; * Use of the following anti-viral agents: ribavirin, adefovir, lamivudine or cidofovir within 7 days prior to day 1; or pegylated interferon (PEG-IFN) (within 14 days prior to first administration of ColoAd1) * Administration of an investigational drug within 28 days prior to first dose of ColoAd1 * Major surgery within 4 weeks or radiotherapy within 3 weeks prior to first dose of ColoAd1 * Another primary malignancy within the past 3 years (except for non melanoma skin cancer or cervical cancer in situ) * Central nervous system (CNS) metastasis that is symptomatic and/or requires treatment * Any condition or illness that, in the opinion of the Investigator or the medical monitor, would compromise patient safety or interfere with the evaluation of the safety of the drug * Known allergy to treatment medication or its excipients * Any other medical or psychological condition that would preclude participation in the study or compromise ability to give informed consent Phase II Specific Exclusion Criteria: * Progression on first line therapy * A complete response on first line therapy * Use of first line therapy for longer than 4 months * Use of any first line treatment with a chemotherapy regimen other than FOLFOX, FOLFIRI or CAPOX (each with or without bevacizumab) * More than 6 weeks since the last administration of 5 FU, capecitabine, oxaliplatin or irinotecan