Challenge Theme R&D spotlight: Development of an end-to-end scalable AAV platform

In this interview, Amna Anwar, Associate Senior Scientist at the Cell and Gene Therapy Catapult, highlights one of our Challenge Theme research projects involving the development of an end-to-end scalable adeno-associated virus (AAV) production and purification platform.

1. Please provide an overview of the work presented in this poster.

This poster highlights the development of our end-to-end scalable AAV2 production and purification platform which has been demonstrated at both a two and 50 litre production scale. The process has been well characterised through internal and external analytical assays which measure process performance and critical quality attributes (CQAs) throughout the purification process.

2. What are the challenges associated with the production of AAV?

The detection, production, purification, and delivery of AAV requires dedicated development to ensure cost efficient and effective manufacture of next generation ATMPs. One of the challenges associated with the production of recombinant AAV (rAAV) is the formation of empty, partially full or mispackaged AAV particles that do not contain the full therapeutic gene. Only a small percentage of these particles are infectious and would achieve clinical output in vivo.

AAV production processes need to be robust and scalable, and the development of effective purification methods at large scale to separate empty, partially full and full AAV particles is still a challenge because of the similar physio-chemical characteristics.

3. How does this project contribute towards addressing the challenge of developing efficient AAV production processes?

The outcome of this project was the successful development of a robust AAV production and purification platform that performed highly at both a small and large scale and was successfully tech transferred to several of our collaborators.

The ability to effectively upscale this process is essential as this can ultimately help to support the wider industry with the production of sufficient AAV vectors to meet clinical demand, and the opportunity to tech transfer to different sites can help our collaborators to accelerate the establishment of their own baseline AAV processes.

4. What were the key requirements for developing a robust and scalable AAV production platform?

To ensure the delivery of an effective AAV production platform that can maintain high performance at different scales, it was essential to make it:

  • Consistent - Multiple consistency runs were performed at both scales to demonstrate robustness
  • Highly adaptable for scale-up and suitable for GMP - This was achieved using closed processing methods and scalable equipment and consumables
  • Possible to process quickly - For the downstream operations this allows operators working at large scale to complete individual unit operations within a standard shift

5. What were the difficulties involved in developing this platform and how did you overcome these?

The main difficulties involved in developing this platform were inconsistencies in process performance at a two litre scale compared to a 50 litre scale. This was primarily due to:

  • The difference in equipment used at different scales and facilities
  • Variability in results when using a direct scale-up approach at different scales

Despite developing methods with good theoretical scalability, the reproducibility of the method at scale cannot be verified until it has been tested. To overcome these issues, both the process development team and the manufacturing innovation team worked together to optimise the production and purification methods.

6. What have been the positive outcomes of this project for CGT Catapult, and for the wider advanced therapies industry?

We have been able to demonstrate a scalable and robust, end-to-end platform for the production of AAV. This project involved a successful internal tech transfer from our labs in London to our Braintree Manufacturing Innovation Centre where the process was scaled up from a two to a 50 litre scale. This was a challenging task where we learn how valuable it is to consider GMP requirements during process development, and the importance of developing robust analytics early on to ensure thorough characterisation of the process. Our collaborators are able to leverage our tech transfer and AAV platform expertise to establish or improve their own viral vector manufacturing processes.

Further to this, the two litre process was tech transferred to three collaborators’ sites where we supported the upskilling of their operators through intensive training. This has been a great opportunity to support the industry, particularly smaller academic groups, who are looking to develop their own advanced therapy manufacturing capabilities.

7. What are your plans to build on the achievements of this project to continue improving the efficiency of AAV production processes?

We are now focussed on improving process control using PAT in the up and downstream process to enable adaptive control, and intensifying the process to increase volumetric yield, reduce costs and improve sustainability.

We are looking for collaborators to work with us and continue improving the efficiency of AAV production processes. Contact us to get involved.