ARDAT

Overview

Project Summary

Adeno-associated virus (AAV) is a non-enveloped virus that can be engineered to deliver DNA of interest to target cells for gene therapy purposes. However, pre-existing immunity renders AAV vectors inefficient as they get eliminated from the host. The EU-funded ARDAT project is bringing together experts in the field of gene therapy to fill the knowledge gaps regarding the immunogenicity of AAV vectors in gene therapy applications. Moreover, partners will study the metabolism of AAV gene therapy vectors, their degradation rate and their capacity to persist in episomal form. The long-term vision of ARDAT is to improve AAV vector efficiency in gene therapy trials.

Main Goals

Major current hurdles for wide clinical use of AAV vectors are attributable primarily to: (i) host elimination by both immune and non-immune sequestering mechanisms – such neutralization by host antibody responses critically limits the possibility of repeated AAV delivery; (ii) AAVs are prevalent in the environment and hence a large proportion of the population carry AAV antibodies (up to 80%)– this pre-existing immunity renders AAV unable to infect target cells forcing substantial patient cohorts to be excluded from clinical trials.
The current proposal is founded on compelling track record in the field and brings together a ‘best-with-best’ multidisciplinary team of international leading academic and EFPIA partners with complimentary expertise in gene therapy, immunology, chemistry, engineering, biotechnology, drug safety, viral vector production, regulatory and clinical trials. The overall goal is to analyse the currently available clinical data and then design preclinical and clinical studies to fill the knowledge gaps in advanced therapies development. Our main aims are to: 1) Develop improved model systems for predicting product immunogenicity in humans. This will be achieved by generating human and NHP 3D hepatic models; 2) Enhance our understanding of gene/cell therapy drug metabolism inside a host of cell types. The plan is to define metabolism of the therapeutic vector genome in different cell types to understand whether rates of degradation, episomal maintenance, or integration, and metabolic stress induced by AAV vector transgene expression vary from cell to cell. We will then adopt strategies to mitigate the loss of vector genomes and improve persistence; 3) Use diverse clinical expertise to establish the clinical factors around pre-existing immunity limiting patient access to advanced therapies therapy; 4) Engage regulators to ensure that the concepts and the data generated through this IMI programme will fill the gaps and support furture trials.

Project Details