TITAN (Tumoural Injection of T-VEC and Isolated Limb Perfusion)

Inclusion Criteria: 1. Males or females aged 18 years. 2. A confirmed histological diagnosis of in-transit malignant melanoma with or without regional lymph node metastases or limited visceral metastatic disease (AJCC Stage IIIb/c and IVa/b) or locally advanced soft-tissue sarcoma with or without regional or distant metastases (T2a/b, N0/1, M0/1) suitable for isolated limb perfusion. 3. Life expectancy of at least 3 months (as assessed, and documented by the Chief Investigator). 4. ECOG Performance Score of 0 to 2. 5. No continuing acute toxic effects of any prior radiotherapy, chemotherapy or surgical procedures, i.e., all such effects must have resolved to Common Terminology Criteria for Adverse Events (CTCAE, Version 4.0) Grade 1. 6. Completed any previous chemotherapy at least 28 days before entry into the study. 7. Have baseline laboratory results as follows: * Absolute neutrophil count (ANC) 1.5 × 109 \[SI units 109/L\]; * Platelets 100 ×109 \[SI units 109/L\] (without platelet transfusion); * Haemoglobin 9.0 g/dL \[SI units gm/L\] (with or without red blood cell (RBC) transfusion); * Serum creatinine 1.5 × upper limit of normal (ULN); * Bilirubin \< 1.25 × ULN * ALT, AST and and alkaline phosphatase \< 2 × ULN; * Calcium \< 12 mg/dl (2.99 mmol/l). 8. Provide written informed consent in accordance with all applicable regulations and follow the study procedures. Patients must be capable Exclusion Criteria: 1. Known cerebral metastases. 2. Have had concurrent immunotherapy during, and for the number of days equal to the half-life of that agent before or during, the study therapy. 3. Evidence of immunosuppression for any reason: * Known HIV disease * Acute or chronic hepatitis B or hepatitis C infection. * Chronic oral or systemic steroid medication use at a dose of \> 10 mg/day of prednisolone or equivalent. * Other signs or symptoms of clinical immune system suppression. 4. Open herpetic skin lesions. 5. A history of hypersensitivity to T-VEC or its excipients. 6. Pregnant or breast-feeding female. Confirmation that women of childbearing potential are not pregnant with a negative serum and urine beta-human chorionic gonadotrophin (beta-hCG) pregnancy test results must be obtained within 7 days prior to treatment initiation (i.e. the 1st administration of T-VEC). 7. Fertile males and females who are unwilling to employ highly effective means of contraception during study treatment and for 3 months after the last dose of study treatment. 8. Previous treatment with T-VEC for active disease. 9. Require intermittent or chronic treatment with an anti-herpetic drug (e.g. acyclovir), other than intermittent topical use.