Dr Themis did his PhD at Brunel University London in 1994 then moved to St Mary’s Hospital, Paddington where he worked on developing novel ways to improve gene transfer by retrovirus and adenovirus vectors. He then went on to work at Imperial College London in 2000 as an MRC funded research fellow in the group of Charles Coutelle. Dr Themis stayed at IC until 2006 focussing on the correction of animal models of disease. In 2006 he was the first to show permanent correction of haemophilia B following gene delivery before birth. During his time at IC he also developed the fetal/neonatal model for genotoxicity showing genes involved in hepatocellular carcinoma could be exposed following treatment with EIAV lentivirus vectors. After moving to Brunel University in 2006, Dr Themis won the prestigious Innovate UK, SBRI InMutaGene Challenge. With David Hay here he developed an iPSc based human model to determine gene therapy vector safety, mainly for LV and AAV vectors. Two important patents were generated by this work. In 2017 he founded TestAvec Ltd as the first company that offers genotoxicity assays to evaluate gene therapy safety. He is currently working towards providing a service to establish patient eligibility for gene therapy before treatment and to provide vector safety profiling for academia and industry to present to the regulators in the hope of moving gene therapy more rapidly but safely into the clinic.