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Supporting a Gene Therapy Clinical Trial with Assay to Measure NAbs Against the AAV9 Serotype

Gene therapy is experiencing an exciting resurgence with the development of new genome editing tools and new gene delivery vectors. Approximately 60% of gene therapy candidates in the pipeline today use a viral vector, with the adeno-associated virus (AAV) emerging as the most prominent choice due to its safety, low to moderate immunogenicity, and flexibility to be engineered for very specific functionality across a wide range of clinical applications.

Although AAV has demonstrated a favorable safety profile to date, a high prevalence of neutralizing antibodies (NAbs) may be detected against some AAV serotypes, which may impair the efficacy of the AAV transduction in patients.

Therefore, when one of our customers – a biopharmaceutical company targeting rare genetic diseases – came to BioAgilytix seeking rapid turnaround for the development and qualification of a cell-based assay to measure NAbs against serotype 9 of adeno-associated virus (AAV9) for its gene therapy candidate, we understood the potential challenges that we could face.

Study Parameters and Potential Challenges

The developed assay would be used determine the prevalence of pre-existing antibodies against the AAV9 serotype in patients for the clinical trial. This specific strain of AAV has been described to show limited transduction efficiency for most cell lines. So, our method would need to increase transduction efficiency and minimize possible matrix interferences.

The development and qualification of the cell-based NAb assay was non-regulated, but the validation and clinical sample analysis performed at both our USA and European laboratory facilities would fall under GCP regulations. Our objective was to specifically detect pre-existing antibodies with a high level of precision.

Solving with Global Resources

BioAgilytix’s global team is comprised of some of the most seasoned experts in cell-based neutralizing antibody assays, particularly for gene therapy vectors. As such, our scientists in the USA and Europe were able to collaborate to create the optimal assay conditions required to effectively determine prevalence of pre-existing antibodies against AAV9.

In particular, we employed a specialized host cell line with unique culture conditions to enhance virus transduction and in turn better distinguish between NAb positive and NAb negative samples. Our Cytation™ 3 cell imaging plater reader was used to deliver luminescent reporter gene readouts with a high level of accuracy.

Our team was also able to meet the customer’s stringent timeline by using assay-ready cells to facilitate rapid turnaround of results.

A Successful and Transferrable Solution

Using the developed assay, we were able to perform statistical analysis for cut point determination with high prevalence of pre-existing antibodies. Preclinical and clinical studies are currently running in our laboratories in both Europe and USA using the customized cellular NAb assay, and the project remains on time and on track for next steps.

It is also important to note that while used in this particular case to measure NAbs against the AAV9 serotype, the developed assay is a transferrable method that can be applied to many gene-therapy related studies.

Partner with the Scientists at BioAgilytix

BioAgilytix is here to partner with you in your efforts to bring impactful novel drugs to market, and our team has extensive experience developing novel approaches to overcome complex bioanalytical challenges. Explore additional case studies to see this ingenuity first-hand, or speak to one of our scientists today about your study requirements.

Assay to Measure NAbs Against the AAV9 Serotype