The advantages of single-use systems have been well documented in biomanufacturing for over a decade and are frequently used in the manufacture of monoclonal antibodies. Key areas where single-use systems provide real benefit over stainless steel counterparts is in reducing production change-over time and decreasing the cleaning and validation that requires significant time, labor, water and utility costs. Single-use systems also enable flexible facilities, require less capital investment and are quicker and easier to initiate than stainless steel facilities. These technologies are also often compatible with process automation.

While certainly beneficial to monoclonal antibody production, there is even a more compelling case for using single-use technology in viral production, specifically for viral vectors and vaccine manufacturing, where even a small cross-contamination could be detrimental. Within viral production, one area where single-use can provide a significant benefit is in tangential flow filtration (TFF). TFF is frequently used during viral vector manufacturing to concentrate, exchange buffer and in final formulation. The compact system design also allows for low minimum recirculation volume for high concentration factors and product recovery.

ÄKTA readyflux XL

Cytiva has offered their ÄKTA^TM readyflux^TM, an automated, single-use TFF system for pilot and small-scale manufacturing since 2017. They have recently added to their product portfolio with the ÄKTA readyflux XL, which provides the same benefits at large-scale operation. The systems both feature a single-use flow path that minimizes the cross contamination risk, reduces the need for cleaning, and shortens the batch change-over time. In addition, automated filtration protocol capabilities in both upstream and downstream applications simplify automation implementation. Automation capabilities include extensive monitoring and control functions.

Benefits to Viral Vector and Vaccine Manufacturing

Closed, Aseptic Manufacturing

Because the ÄKTA readyflux and ÄKTA readyflux XL are single use, they enable a closed and aseptic process. This is an important consideration in viral vector manufacturing where viral clearance can be more challenging, particularly with lentiviral vectors. The aseptic processing capability also vital at instances where the entity can not or should preferably not be sterile filtered.

The single-use flow kits used with the ÄKTA readyflux systems are supplied gamma irradiated and include single-use flow path, pumps and sensors for pressure, conductivity, temperature, flow and pH. The flow kits are easily installed and available with aseptic connectors to maintain a closed flow path. In addition, ReadyToProcess^TM hollow fiber filters are delivered pre-sterilized and ready for use. A single-use flow path minimizes cross-contamination risk and bioburden issues.

In contrast, stainless steel systems require significant clean-in-place (CIP) and generate considerable waste liquid. In addition to keeping the operation closed, single-use flow kits also keep the disposal of waste closed. Sealing the kit and tubing means that contents have no exposure to the environment and pose no risk to operators, particularly important when working with highly toxic substances like ADC and contagious viruses and microorganisms.

Flexible Facilities

The rapid response to Covid-19 highlights the importance of having flexible facility use and the ability to add additional capacity quickly and easily. The use of viral vectors in some of the front running Covid-19 vaccine candidates, places further demand on already stretched viral vector manufacturing capacity.

By employing flexible, easy to use, single-use systems, facilities can be deployed efficiently and at less capital expense. The ÄKTA readyflux systems offer a wide flow range to accommodate specific applications and the small footprint (one meter²) permits them to be moved around to meet the needs of multiple campaigns. They support the use of a wide range of single use bags and they can be used with both filter cassettes and hollow fiber filter cartridges.

Xcellerex^TM XDUO single-use mixers can be connected to the system to monitor and control liquid volumes. Also, third party mixers can be used for monitoring. Analog inputs make it possible to connect third party equipment, thus ensuring smooth integration into an existing facility.

Process Automation

Automation provides consistency and reduced risk of operator error. The ÄKTA readyflux systems are able to control and monitor pressure and level of concentration among other functions.

Automation of TFF can also increase the speed and scale up of the process. A broad flow-rate range with a low hold-up volume and multiple filtration control features enable the user to tailor the process control modes to optimal operation conditions. This supports a fast filtration process that further reduces risk to the product, as the duration of the process is always a concern for unstable viruses. Hollow fiber filters have also been shown to reduce shear, another area of concern with production of lentiviruses.

UNICORN^TM software provides intuitive and flexible method creation, automated system control and process evaluation to simplify filtration tasks. The wide variety of control modes helps users tailor the filtration controls to different processing requirements. The systems are compatible with both UNICORN and DeltaV^TM control systems.

Scalability

The ÄKTA readyflux and ÄKTA readyflux XL provide scalable filtration from process development to large scale GMP manufacturing. The two systems have the same processing capabilities, thus ensuring easy and successful transfer and scale up for the entire process.

Ease of Use

Set up is surprisingly easy by installing the flow path on the system and setting up the software. With clean and reuse systems, the framework is open with cables and process pipes interfering with the vision of the flow path. Single-use flow paths are clearer and it is easy to see where the liquid is going, something that operators can appreciate.

Summary

The need to increase capacity for viral production is a pressing demand on the industry as the gene therapy clinical pipeline continues to grow. There is also a critical imperative to produce large amounts of vaccine to tackle the Covid-19 pandemic. Implementing single-use systems like the ÄKTA readyflux systems, enables rapid deployment of facilities to build capacity quickly and the flexibility of the system permit them to be connected with existing equipment. It also significantly reduces CIP and validation steps that speeds change-over between campaigns. Automation increases the speed, monitoring, and consistency of the process.

Lastly, closed manufacturing is vital with viral production and single-use flow paths minimize cross-contamination risk and bioburden issues. It is clear that TFF plays an important role in viral production and a single-use TFF option offer high level benefits to the overall manufacturing process.

For more information, please see ÄKTA readyflux