Study of RP3 Monotherapy and RP3 in Combination With Nivolumab in Patients With Solid Tumours

Inclusion Criteria: * Patients with advanced or metastatic non-neurological solid tumors, who have progressed on standard therapy or cannot tolerate standard therapy, or for whom there is no standard therapy preferred to enrollment in a clinical study * All patients must consent to provide archival tumor biopsy samples within 12 months, or a fresh tumor biopsy is needed. Patients must also consent to provide on treatment biopsies as per protocol * At least one measurable tumor ≥ 1 cm in longest diameter (or shortest diameter for lymph nodes) * At least one injectable tumor ≥ 1 cm in longest diameter or injectable tumors which in aggregate are ≥ 1 cm in longest diameter (or shortest diameter for lymph nodes * Have an Eastern Cooperative Oncology Group (ECOG) performance status 0-1 Note: Predefined inclusion criteria may apply for each additional expansion cohort. Exclusion Criteria: * Prior treatment with an oncolytic virus therapy * History of viral infections according to the protocol * Systemic infection requiring intravenous (IV) antibiotics * Active significant herpetic infections or prior complications of HSV-1 infection (e.g., herpetic keratitis or encephalitis) * Requires intermittent or chronic use of systemic antivirals a. Hepatocellular carcinoma patients with a diagnosis of hepatitis B must be off antiviral therapy for at least 4 weeks prior to enrollment . Hepatocellular carcinoma patients with a history of or ongoing hepatitis C infection must have completed treatment for hepatitis C at least 1 month prior to study enrollment and hepatitis * History of interstitial lung disease * Has a history of (non-infectious) pneumonitis that required steroids or has current pneumonitis Additional Exclusion Criteria for Patients Enrolled in Part 2 (Expansion Cohorts): * History of life-threatening toxicity related to prior immune treatment or any other antibody or drug specifically targeting T-cell co-stimulation or immune checkpoint pathways * Treatment with botanical preparations within 2 weeks prior to treatment. * Active, known, or suspected autoimmune disease requiring systemic treatment. * History of interstitial lung disease. * Severe hypersensitivity to another monoclonal antibody. * Has received prior radiotherapy within 2 weeks of start of study treatment. * Has received a live vaccine within 28 days prior to the first dose of study treatment. * History of (non-infectious) pneumonitis that required steroids or has current pneumonitis. * History of myocarditis or congestive heart failure within 6 months of screening. * Has a serious or uncontrolled medical disorder. * Has a QT interval corrected for heart rate using Fridericia's formula (QTcF) \> 480 msec, except for right bundle branch block.