July 4, 2022

Safe handling of AAVs

Adeno-associated viruses (AAVs) represent one of the most promising vectors for gene therapy and vaccines. To deliver AAVs and related products of the highest quality and purity, there is a need for technologies and platforms that facilitate reliable and safe handling all the way from the first steps in production right up to the shipping and storage processes.

Safe handling AAVs

AAVs in biopharma – what are they used for?

AAVs were initially developed as a promising nonpathogenic vector for gene therapy, used to treat neurodegenerative diseases of the central nervous system. AAVs can deliver a therapeutic gene directly to the central nervous system, providing long-term functional correction of missing or mutated genes. Today, AAV technology has advanced and is now able to target a wide range of tissues and cells for the treatment of several diseases, including Parkinson’s and Alzheimer’s diseases.

AAVs are favored for their generally safe profile: They do not cause disease in humans nor do they need other viruses to replicate. This makes them an ideal choice for transferring and delivering genes to target a number of different tissue and cell types, with the goal of improving the health of patients, and even curing them, where traditional approaches have failed.

The continuously growing number of clinical trials and new products calls for production technologies and platforms that are flexible enough to meet the requirements of both laboratory- and bulk-scale production without the need for major adaptations. This can be provided by single-use technologies and the modular design options they offer.

What to consider when dealing with adeno-associated viruses

AAVs and indeed any medical drugs or therapies are valuable products, with much at stake if something goes wrong during their production. Time is a crucial factor and, when time is of the essence, efficient procedures must be in place to ensure speedy, user-friendly, and reliable processes and handling. 

This requires flexibility and scalability in order to skip tedious and time-consuming adaptations that may result in contamination. Single-use systems have proven to be easy to handle while offering the highest levels of flexibility, so that production platforms can be scaled from prodcucing minuscule amounts to bulk production.

Dealing with adeno associated viruses

Risks when dealing with AAVs

AAVs are not known to cause human disease; in addition, they cannot replicate in the human body like other viruses can. This is why they have become the dominant vector for gene therapy, with a number of clinical trials underway.

In terms of biosafety, recombinant AAV constructs can be handled in a Biosafety Level 1 facility as long as they are produced in the absence of a helper virus and do not encode a potentially tumorigenic gene product or a toxin molecule. Otherwise, they should be handled as a biohazardous material under Biosafety Level 2 containment.

How are AAVs properly dealt with?

While viral vectors can be stored at -20°C or even +4°C for short periods of time, long-term storage requires a temperature of -80°C, which is where ultra-cold freezers come in. AAVs must be aliquoted into single-use portions to avoid repeated freeze-thaw cycles. 

Single-use technologies are the ideal choice to ensure consistent freezing results while maintaining the characteristics and quality of the frozen product.

AAV manufacturing – ensuring safety along the supply chain

Due to their highly sensitive nature, AAVs should be handled with the greatest of care. In line with regulatory requirements and industry standards, safety and sterility must be ensured along the entire supply chain. 

This is where end-to-end solutions based on single-use technologies offer the perfect option, as they allow the greatest flexibility and agility. Furthermore, single-use designs are fully disposable, thus enabling a completely sterile fill process. 

Automated filling – the RoSS.FILL platform

Single Use Support’s RoSS.FILL platform allows for a fully automated and monitored filling process that can be scaled to meet varying needs, all the way from preclinical to bulk production.

Furthermore, all of the other components and packaging materials necessary, such as single-use bags and vials (which can be protected by RoSS.shell throughout liquid transfer processes), are equally flexible and adaptable to different requirements and platform designs.

With RoSS.FILL, you can dispense unlimited volumes per batch, at speeds of up to 300L per hour, into single-use bioprocess containers.

RoSS.FILL - aseptic single-use filling and draining system for Cell & Gene therapies

Ensuring AAV cryopreservation via ultra-cold plate freezing – RoSS.pFTU

A reliable freeze-thaw process that gives consistent results is extremely important to maintain the characteristics of AAVs.

Unlike static freezers, plate freezing platforms allow for close contact with the cold surface, which is only separated from the AAV particles by a thin polyethylene layer and the stainless-steel lid of the RoSS shell and thus guarantees optimal temperature transfer. This not only prevents cryoconcentration but also leads to a more uniform outcome than static freezers would ever be able to offer, thereby maintaining the characteristics of the frozen substance. 

Single Use Support’s freeze-thaw platform RoSS.pFTU provides controlled freezing/thawing for the cryopreservation of any pharmaceutical substance and can be easily scaled from laboratory to medium- or large-scale requirements.

RoSS.pFTU large-scale

Leaving the manufacturing site – secure transport and storage options by Single Use Support

Once frozen, AAVs must be stored and shipped in a protected manner and in an environment that ensures their frozen state is maintained. 

Single Use Support’s RoSS.FRDG is an ultra-cold storage freezer that maintains the desired set-point temperature and is scalable for different purposes. In addition, it is stackable, fully movable, and modular, to facilitate easy handling and compact storage. It not only allows for a seamless transition between deep-freezing and shipping or thawing but also offers a high degree of flexibility due to its portability.

Ultra-cold storage RoSS.FRDG
Safe handling AAVs

Mike Marciniak

Senior Director, Business Development US