Development of a Potency Assay for an AAV-Encoded Transgene Regulated by Retina-Specific promoters using iLite reporter-gene technology

Tovey M, Huang L, Lallemand C, Rodo J. Svar Life Science AB, Malmö Sweden Recent breakthroughs in gene therapy have opened avenues for treating previously incurable conditions such as rare diseases. However, the therapy is complex and multifactorial, with several steps that need proper assessments, with the potency of the produced transgene product and the AAV vector being key components. This case study describes a novel reporter gene cell line based on the iLite® technology, designed explicitly for potency assessment of both transgene products and the AVV vector. The versatile platform features an operator-promoter system integrating a cGMPspecific receptor protein (CRP) and a potent transactivation domain, tightly regulating a firefly luciferase reporter gene, resulting in a perfect tool to assess the potency of the transgene in a functional and specific manner. The use of human-derived cell lines alongside a reporter mechanism that accurately simulates the mode of action offers a significant advantage for the precise assessment of gene therapy potency. Such innovative approaches represent perfect tools to assess potency based on the true mode of action, which is the final result of upstream events like viral transduction, transgene expression and translation. Therefore, they have the potential to replace a multitude of assays that are typically applied to assess gene therapeutic drug potency by a matrix approach.