A human iPS cell model for gene therapy vector safety evaluation

We are developing a robust human relevant risk assessment system that will improve the safety of novel gene therapy products and reduce the reliance on animal models.

Gene therapy (GT) is now emerging as a medical reality, with clinical efficacy demonstrated in a number of GT trials for rare diseases. Generally the therapeutic DNA sequence is delivered via a vector system, with some vectors integrating permanently into the genome to provide ex vivo or in vivo gene addition or correction for the treatment of inherited and acquired disorders. The integrated sequences are then transmitted to the cell progeny during cell replication. Insertional mutagenesis leading to oncogenesis is a recognised GT safety concern, which has manifested in a number of trials involving ex vivo transduction of hematopoietic stem cells with gamma-retroviral vectors. There is increasing demand for non-clinical tests to assess the safety of GT in patients. Non-clinically, GT safety is mainly assessed through in vivo studies in rodent or non-rodent species. These animal models are costly, time consuming and do not always reliably predict the effects seen in humans.

Supported by funding through the NC3Rs CRACK IT Challenges competition, the team led by GeneWerk GmbH has already set up the basis of a standardized assay for Individualized Genotoxicity testing (InGeTox) to assess vector safety and efficacy using human induced pluripotent stem cells, differentiated to hepatocytes in 3D culture with extended lifespan. Vector-related factors that cause genotoxicity will be measured, including effects on cancer gene expression by vector promoters and enhancers, aberrant transcript forms or gene splicing, host epigenetic responses to gene transfer and therapeutic gene expression. InGeTox will be made expandable to Patient cells and each tissue of interest, representing a personalized safety assessment for each disease targeted by gene therapy.
We are collaborating with Brunel University, Edinburgh University, University College London, King’s College London, The Natural and Medical Sciences Institute at the University of Tubingen (NMI), GlaxoSmithKline and Novartis to deliver InGeTox.

“Whilst avoiding animal experimentation, together we will be accelerating the transition of safe gene therapy from bench to bedside!”
M. Schmidt, CEO GeneWerk