Cell and gene therapies (CGTs) have begun to transform the landscape of therapeutic offerings for patients with genetic diseases and other medical conditions. For many emerging biopharmaceutical companies, CGTs utilizing an adeno-associated viral vector (AAV vector) form the basis of the company’s product development pipeline—making selection of an optimal manufacturing platform a pivotal point in development decision-making.
Knowing the options for AAV vector production platforms
Proper platform selection for AAV vector production must take into account the targeted patient population, the desired yield, and the potency requirements.
Manufacturing platform options include:
- Transient transfection of adherent/suspension HEK293 cells: Adherent-based processes contain animal-derived components and require a large footprint due to scale-out methods, while suspension-based platforms are serum-free and can be scaled up, with limitations. Transient transfection utilizes large volumes of plasmid DNA, resulting in a high cost of goods (COG) per batch. As starting material is not produced as part of the vector manufacturing process, timelines to clinic can be shortened.
- Baculovirus expression vector system utilizing insect SF9 cells: This method offers low toxicity and large packaging capacity for gene insertion, as well as low multiplicity of infection (MOI), for maximum AAV productivity. The multi-step process to generate optimal starting material introduces complexity and extends the timeline, but this platform allows large-scale (up to 2000L) batches for vector manufacturing.
- Packaging or producer cell lines—stable transfection systems: As genes are stably transfected into the cells, expression of the target genes can be initiated by either adenovirus infection or by removal of the inhibiting agent. This results in low COG required for starting material. Manufacturing batch scale can be performed at large volumes using various suspension platforms, but timelines to generate an optimal producer cell line and to address any potential impact to vector potency can be challenging.
- Herpesvirus helper processes utilizing mammalian cells: This method offers large packaging capacity to carry gene inserts but requires high MOI of the starting material. HSV must be generated as seed stock for AAV production using laborious adherent process methods for every batch of vector manufacturing.
Choosing a viral vector manufacturing platform that works for you
When deciding among the above AAV vector manufacturing platforms, remember our top tips:
1. Don’t compromise on critical quality attributes (CQAs)
Critical quality attributes (CQAs) are key in the monitoring of product quality during the manufacturing process, and include viral potency, identity, quantity, process residuals, aggregation, empty capsids, protein content, and product safety. Assays and their suitability depend on the specific type of purified virus and what expression system was used. They must be robust enough to meet early clinical development requirements and ongoing quality standards to avoid costly rework or roadblocks.
2. Identify the cost of goods in relation to scale of production
The cost of raw materials varies from platform to platform. All platforms use costly single-use technology, but the biggest expense is typically a platform’s need for seed stock, serums or plasmids, or scale-out methods for generation of the target vector yield.
3. Keep both immediate and long-term timelines in mind
From the inception of your process to the first batch release of clinical material, the time to clinic for most platforms is 16-24 months. And since virus helper systems and packaging/producer cell line systems need initial tools developed—which could take up to 6 months more—it’s best to start this process development in tandem with use of population viruses and/or transiently transfected cells. Consider how soon you can realistically take the viral vector to market, and which platform may position your product most effectively both scientifically and commercially long-term.
Conclusion
Thoughtfully selecting your manufacturing platform will help you maximize your productivity, optimize your timeline, achieve better quality control, and better position your viral vector for commercial success.
Choose a CDMO that can intelligently and strategically guide you through the decision process, and learn more about how to select the right platform in our whitepaper: Evaluating current manufacturing platforms for recombinant AAV production.
Author:
Samira Shore, Director Technical Program Design, Thermo Fisher Scientific
[email protected]