Streamlining Downstream Processes

As biopharmaceutical manufacturers seek greater efficiency and intensification of downstream processes, process automation stands ready to offer improvements. Automated process control enables efficient operation of connected systems and reduces variability and error. Process analytics collect and analyze large amounts of real-time data to improve process monitoring and control. Process automation, as well as robotic handling in some cases, facilitates the use of closed systems that reduce the risk of manual intervention. Smaller footprints and faster production boost capacity to meet the increasing need for biopharmaceutical therapies.

Purification

The Sartorius Resolute BioSC platform intensifies downstream processing using an automation system to connect steps including chromatography, virus inactivation, and polishing. The connected system reduces the equipment footprint and process time. For example, Sartorius collaborated with Enzene Biosciences to improve a monoclonal antibody (mAb) purification process (1). First, a batch process was developed to remove the intermediate buffer adjustment step. Next, the unit operations were run in a connected mode, using a fully automated BioSC modular system, which reduced the overall equipment footprint by approximately 80% and processing time by approximately 40%, the company reports in an interview with BioPharm International.

In an ongoing collaboration between Rooster Bio and Sartorius, the companies are working together to commercialize a human mesenchymal stem/stromal cell (hMSC)-based exosome production platform (2). Sartorius’ automated, batch benchtop filtration systems (Sartoflow Smart and Sartoflow Advanced) will be used in the downstream processing operations. These tangential flow filtration (TFF) systems are optimized for ultrafiltration and diafiltration applications and already used in many downstream processes, such as purification of vaccines, mAbs, and recombinant proteins.

Cytiva’s automated, single-use filtration system (ÄKTA readyflux) is used in TFF operations and in normal flow filtration. One or more TFF units are used in workflows to manufacture many types of biopharmaceuticals, including mAbs, plasmid DNA (pDNA), viral vectors, and mRNA. The equipment is available with different industrial automation control solutions. “Unicorn is the standard control, but PlantPAx via Unicorn OPC [open platform communications] connection and DeltaV automation systems are also available. The system can be a stand-alone unit operation, connected via OPC to a historian for data integration, or [have] full integration via Unicorn OPC into a [distributed control system] layer,” reports the company in an interview with BioPharm International. “Automation, across the workflow, can improve quality by reducing variability and errors.” In February 2023, Cytiva announced that Australian contract development and manufacturing organization AcuraBio would use Cytiva’s two-step purification protocol and ÄKTA readyflux in a FlexFactory configurable manufacturing train to manufacture pDNA (3).

Single-use system handling

In downstream processing of biopharmaceuticals, such as mAbs, there is a continuing push to greater efficiency through process intensification using single-use, multi-product facilities as well as more data analytics and process automation. For single-use systems, it is crucial for systems to be handled and integrated properly. Proper installation and use are facilitated by appropriate physical design and other features, such as physical and electronic tags on the system and the assembly.

Stuart Tindal, chair of the Bio-Process Systems Alliance automation committee and product manager of Intensified Downstream Systems at Sartorius, adds that although installation and tear-down of single-use systems is primarily manual, process automation systems can now support operators performing these functions. For example, step-wise user guidance can be communicated from the human-machine interface, and tools such as contact verification sensors can be used to ensure that connections are made and are secure. Through digital linking and single-use consumable design, the automation system can identify the single-use assembly and upload the material article and lot number into the system batch details via a camera and label-text and code recognition, explains Tindal. Automation thus reduces the risk of transfer error that is inherent in a human reading and entering information.

Darren Verlenden, head of Process Solutions at MilliporeSigma, adds that because an important advantage of single-use bioprocessing is flexibility, the automated system must be designed to easily adapt to different assembly configurations, bag volumes, and tubing sizes. In addition, the sensors that are part of automated processes (e.g., non-contact flow meters, pressure probes, pH probes) must be compatible with single-use flow paths.

Process analytics

Process automation requires a shift away from in-process manual sampling with off-line analytics toward in-line or on-line process analytic technologies (PAT) that enable continuous measurements of critical parameters and critical quality attributes (CQAs), says Verlenden. Spectroscopy continues to be an important in-line measurement tool for monitoring CQAs in bioprocessing. “We are seeing continued advancement of ultraviolet, infrared (IR), near-IR, and Raman spectroscopies. In particular, Raman spectroscopy holds the potential for providing the most complete molecule and impurity information, while being minimally impacted by water signal. [MilliporeSigma’s] ProCellics Raman analyzer can provide continuous and immediate insights into protein concentration, aggregation, and the presence of impurities.”

In cases where in-line technologies are not compatible with analytical requirements, MilliporeSigma’s Modular Automated Sampling Technology (MAST) allows samples to be extracted and delivered to analytical instruments for “near real-time analysis” while maintaining sterility, adds Verlenden. Automated, sterile sampling is gaining traction due to the growing interest in closed processing, he explains.

“As more novel modality therapeutics are moving to the manufacturing floor, there is strong interest to deploy and adapt the PAT tools to them,” suggests Verlenden. “Technologies like automated sampling are modality-agnostic and could be readily used in novel bioprocesses such as viral vector manufacturing.”

MilliporeSigma and Agilent announced a collaboration in June 2022 (4) that included work to demonstrate the utility of on-line high-performance liquid chromatography (HPLC) to monitor and control antibody aggregation levels in bioprocessing. Because aggregation can impact biological activity of the biopharmaceutical, ensuring that aggregates are sufficiently reduced during the process is crucial for ensuring product quality, explains Verlenden. The companies used Agilent’s on-line HPLC as PAT to monitor antibody aggregation levels after flow-through frontal chromatography purification using a cation exchange resin.

“Upon detection of aggregates in the column effluent, automated column switching was initiated to ensure effective and efficient continuous removal of aggregates from the process stream. This study provided a solid proof of concept of physical and digital integration of a processing technology (cation-exchange chromatography for aggregate removal) and on-line analytical technology (HPLC for aggregate detection), which now could be extended to more complex CQAs. We look forward to continuing this collaboration to expand the use of on-line HPLC along the broader bioprocessing workflow and in conjunction with other analytical

instruments,” says Verlenden.

This broader implementation of PAT will enable the industry to make progress toward enhanced process monitoring and control of downstream processes. “The implementation of PAT enables continuous manufacturing and empowers industry progress towards Bioprocessing 4.0,” Verlenden concludes.

CGT operations

Automation is crucial for cell and gene therapy (CGT) manufacturing, where demand currently outstrips supply; closed, end-to-end robotic automation platforms aim to create a step change in capacity (5). Automated and closed unit operations make a difference in both integrated operations and in separate upstream and downstream operations.

Thermo Fisher Scientific introduced the Gibco CTS DynaCellect Magnetic Separation System (DynaCellect), an automated and closed system for cell isolation, cell activation, cell depletion and Dynabeads magnetic beads removal, in October 2022 (6). The new system eliminates the manual intervention required with the earlier CTS DynaMag tool. “DynaCellect is designed to be an automated accessory for workflows that leverage DynaBeads,” says Evan Zynda, senior staff scientist at Thermo Fisher.

The new, scalable system can help cell therapy developers move from process and clinical development to commercial manufacturing. It is currently used in T-cell therapy manufacturing workflows and is being used in developmental workflows for many other therapy types, says Zynda. The isolation protocol fits a broad target cell range and can be used in autologous and allogeneic processes.

“Scalability stands out as a major consideration when developing a product that can accommodate autologous and allogeneic processes,” says Zynda. “As the industry continues to progress, autologous groups desire to scale down the manufacturing volume and time of these personalized workflows, [which] will allow for a more rapid turnaround time, reduced costs, and easier downstream processing. On the other side, allogeneic processes will be longer and scaled up to create larger batch sizes that can result in several banked doses.” Zynda explains that downstream processing for these larger batch sizes, anticipated for products such as natural killer-cell therapies and induced pluripotent stem cell-derived therapies, could be more cumbersome. He says, however, that the tool will be designed to meet this growing need. “At launch, the DynaCellect could easily accommodate a range of 100 million to 10 billion target cells for isolation, which is compatible with almost all current isolation processes. We have since validated targeting 20 billion cells of interest without issue, and we will continue to develop protocols to push the system further as the need arises.”In addition, the continuous de-beading process can accommodate any volume of bead-containing solution, including smaller autologous batches and larger allogeneic batches, says Zynda.

Zynda adds that automated workflows will be beneficial for decentralized or “point-of-care” manufacturing sites, which are less likely to have specialized, trained technicians. “Creating a closed and automated workflow not only enhances efficiencies, it also increases cell therapy manufacturing success rates and reduces failures,” he adds.

Technology provider Invetech also sees a need for modular solutions for unit operations that can speed up the manufacturing process for cell therapies (7). The company’s Korus closed system for elutriation and cell wash using gentle counterflow centrifugation was launched in June 2022 (8). “Manufacturing efficiency of cell therapies needs improvement and innovation if the cell therapy industry is going to reach its commercialization goals,” said Jon Ellis, lead of Invetech’s Cell Therapy Science and Application team, in the press release (8). “Our data shows that whilst achieving similar apheresis lymphocyte cell recovery to the control wash process, Korus eluted lymphocytes to high purity, which resulted in improvements in downstream performance including greater Dynabead cell selection recovery and fold expansion.”

References

• Sartorius. What are the Benefits of a Connected Downstream Process using Resolute BioSC? Webinar, March 29, 2023.
• Sartorius. Sartorius Collaborates with RoosterBio to Advance Downstream Purification Processes for the Manufacture of Exosomes. Press Release, Jan. 5, 2023.
• Cytiva. AcuraBio Expands cGMP Plasmid DNA CDMO Services with Cytiva’s Latest Single-use Purification Technology. Press Release, Feb. 9, 2023.
• MilliporeSigma. MilliporeSigma Announces Collaboration with Agilent Technologies to Fill Industry Gap in Process Analytical Technologies for Downstream Processing. Press Release, June 14, 2022.
• Markarian J. Automation Aids Cell and Gene Therapy Production. BioPharm International 2023 36 (7).
• Thermo Fisher Scientific. Thermo Fisher Scientific Launches Closed and Automated Cell Isolation and Bead Removal Solution to Help Evolve Cell Therapy Manufacturing. Press Release, Oct. 16, 2022.
• Invetech. Where to Next in Cell Therapy Manufacturing? Invetechgroup.com, Sept. 19, 2022.
• Invetech. New Korus Technology Set to Transform Industry Standards in Elutriation and Cell Wash. Press Release, June 21, 2022.

About the Author

Jennifer Markarian is manufacturing reporter for BioPharm International.

Article Details

BioPharm International
Volume 36, No.8
August 2023
Pages 19-21

Citation

When referring to this article, please cite it as Markarian, J. Streamlining Downstream Processes. BioPharm International 36 (8) 2023 19-21.