Creativity and collaboration are required to overcome complex method development challenges.
By Kelvin H. Lee and Mark Lies
Process intensification is of broad interest in the biopharmaceutical industry because of its promise and potential to increase efficiency and thereby reduce the cost of producing drugs and the time it takes to get them to market. Workflows, capital and operating expenses, product quality, and waste production can all be positively impacted by the efficiency gains possible with process intensification.
To develop intensified processes, analytical technologies are needed to assess how those processes are behaving in real-time, or close to real-time, to understand if the process is proceeding as intended and if the quality attributes of the product are within specifications. Those process analytical technologies (PAT) are a critical part of control strategies that ensure continuous operation within the design space.
While many analytical technologies may be classified as PAT, the goal of many manufacturers is to minimize the number of technologies that human operators must manipulate by automating sample collection, preparation, method implementation, and results analysis (inline or online), enabling automated and continuous process control—sometimes thought of as “lights out manufacturing.” The enabling real-time analytical solutions may be based on established and validated techniques, but with improvements in efficiency.
Commercially available PAT solutions that will fuel the rise of intensified processing of therapeutic proteins are limited in number, however. Close collaboration between vendors, manufacturers, and health authorities will accelerate the development and implementation of real-time analytical systems with improved workflows needed to achieve the ultimate goal of real-time release of biopharmaceutical products.
The continuous manufacture of drug substances and drug products will ultimately be useful in the context of real-time release (RTR) (1). While some people believe RTR is a goal to strive for, others believe it is a solvable problem with technology. The interest in RTR is driving the industry to think about process intensification in a more coordinated fashion, and there is a push in the industry to develop and coordinate the integration of analytical technologies that enable real-time process control and, ultimately, real-time release.
The percentage of biopharmaceutical candidates receiving accelerated approval designations has grown dramatically (2,3). Development timelines for these accelerated programs can be half that for traditional programs. Given the reliability of platforms and the maturity of the industry’s understanding of quality, the most important business driver today is speed to market. One consequence of this emphasis on speed is increased demand for more efficient development and validation of faster analytical methods. Rapid inline or online methods that can provide results within seconds to minutes (versus hours, days, or weeks) are now a major focus of PAT and play a significant role in enabling process intensification and shortening development timeframes (4,5).
Current PAT limitations
It should be stressed that current biopharma manufacturing processes are generally robust. As the industry has matured, effective manufacturing platforms and analytical tools and technologies appropriate for fed-batch manufacturing in stainless-steel or single-use bioreactors have also advanced. Current analytical capabilities and approaches are, in fact, quite sophisticated.
There are some sensors currently used to monitor different parameters of cell-culture processes in near real-time, such as pH, turbidity, dissolved oxygen, carbon dioxide production, key metabolite production, cell viability, etc. While these data lead to a better understanding of such bioprocesses and ultimately better process control, improvements and additional capabilities are still needed to achieve true in-line/on-line/at-line monitoring (6).
More complex analyses, such as those required for protein and impurity identification and characterization, are conducted completely off-line. A sample is collected from the bioreactor and taken to a lab somewhere else in the facility (or off-site at another company location or third-party service provider) where it is often manipulated physically and/or chemically to prepare it for analysis.
Analytical labs must have not only the capability (technical expertise and appropriate instruments and software), but the capacity (human, time, and equipment resources) to process these samples and conduct the various analyses. Results for chromatographic, electrophoretic, and enzyme-based analyses are generally provided within several hours. Cell-based assays take days or weeks to complete.
Both sample and instrument challenges must be overcome if some of these off-line methods are to be converted to rapid, at-line solutions. Sampling technologies must ensure that sample collection does not introduce contaminants into the bioreactor. Sample preparation, including both chemical and physical treatments, must be simplified to the point where they can be automated.
Analytical instrumentation should be miniaturized to be suitable for minimal footprint and perhaps designed for remote operation. Tradeoffs between sensitivity and resolution must also be addressed in this case. Algorithms must be developed for rapid analysis of the results and communication of any required actions to process controllers for adjustment of relevant process parameters. Standardized solutions for integration of PAT with process control equipment will therefore be needed.
Thus, for glycoform, host-cell protein and DNA, protein aggregation/fragmentation, endotoxin, and many other analyses that rely on an array of off-line separation and detection technologies, there are multiple opportunities for improvement. The hope is that new PAT solutions can be developed by adapting and improving existing analytical platforms. Liquid/pressure-based chromatographic technologies may present the greatest potential (7). Electrophoretic technologies, which are the gold standard for purity, charge heterogeneity, and other analyses, present more challenges due to the need for sample preparation. Mass spectrometry is of particular interest due to its potential for multi-attribute monitoring.
Improving workflows
One of the keys to developing effective PAT solutions—and also improving off-line and at-line methods as intermediate steps—is simplification. Advances in instrument performance are also essential, but as instrument vendors continue evolving their technologies, they should also be focused on simplifying and streamlining the user interfaces. The key is to create tools that do not require extensive expertise to operate.
PAT solutions will need to be straightforward and ideally require only turnkey, push-button operations. This approach will reduce some of the current workforce development needs with respect to intensive training in instrument operation and sample preparation (e.g., for mass spectrometry glycan analysis), as well as requirements for dedicated laboratory capabilities.
Standardization of interfaces between instruments and for data sharing will also be needed. There is currently significant momentum for consolidation of data formats of all types, including raw data from different instruments and physical interfaces between different pieces of equipment. Without such standardization, and appropriate ontologies, it will never be possible for the biopharma industry to realize Pharma 4.0, digital manufacturing, and the level of automation required to achieve real-time release.
Timeline to real-time release
While the timeline for realizing RTR is difficult to predict due to the significant challenges that must be overcome, progress is being made. PAT solutions based on existing technologies and instrumentation have been applied in an in-line manner by both biopharma companies and academic research groups. These approaches demonstrate that some of these challenges can be addressed if sufficient tools are combined in a single process. Aspects of automation, miniaturization, and multi-attribute methods have also been explored.
This collective work has begun to establish the feasibility of potential in-line processes. These crude solutions will clearly require optimization, but they do confirm the potential value of different strategies to solving some of the issues that must be resolved before more complex PAT systems can be implemented within current good manufacturing practice processes.
It is likely that initial model PAT solutions that provide rapid results in an on-line setting, integrated with process control capabilities for more complex analyses such as capillary electrophoresis, will be developed in the next five to 10 years. Additional solutions will quickly follow.
Developing shared understanding
The biopharma ecosystem desires robust, easiest to use, sensitive technologies for monitoring processes and the quality of products. The faster these technologies can be realized, the more confidence the industry will have in the ability to achieve safe and efficacious medicines in dramatically reduced timelines.
There is a risk to the adoption and implementation of new technologies that might accelerate development timelines, however. Uncertainties exist regarding questions from health authorities on new analytical approaches. Just because a new technology is faster or cheaper does not mean it will make good business sense to implement the technology from a business perspective. Because the biopharma industry is risk-averse, and driven by speed, the incorporation of new technologies can lead to delays in approvals if there is not a shared understanding of the technologies with health authorities.
One way to help advance the understanding of new technologies is for instrument vendors to get their new technologies into the hands of the academic, industry, and regulatory science investigators to develop a shared understanding of the performance and capabilities of those technologies. Where possible, vendors should take advantage of recently introduced formal programs offered by regulatory agencies to discuss new technologies in development and what questions regulators might need answered to fully understand them (8). With this approach, all stakeholders can become more comfortable with adoption of new analytical methods, including novel PAT solutions, before they are implemented in processes.
Need for increased supply chain communication
More collaboration between biopharma companies and vendors early on in the development process would also be beneficial. In many cases today, drug manufacturers identify analytical gaps and work to develop potential solutions, then seek approval from health authorities and assistance from vendors later in the process.
At the same time, regulatory scientists at agencies such as FDA have very sophisticated analytical capabilities and well-trained staff. Increased communication between biopharma manufacturers, their supply chain partners that provide key raw materials, instrument and software vendors, and health authorities can enable greater information and data sharing, which could facilitate the adoption and implementation of novel PAT solutions. Sharing of best practices and potential new analytical techniques at early stages of development can be very powerful.
All stakeholders in the industry are aligned on the end goal: bringing safe and effective medicines to market to advance people’s well-being and health. Each group has a unique perspective though. By creating additional avenues for dialogue and collaboration, more comprehensive discussions about new analytical technologies and their deployment can be driven.
The emergence of industry-led consortia to support the development of manufacturing innovations for the biopharma industry provides a foundation for de-risking some of these activities. The National Institute for Innovation in Manufacturing Biopharmaceuticals (NIIMBL) brings together different stakeholders in the ecosystem (biopharma manufacturers, suppliers, academics, government agencies, and others). By providing a forum for discussions on strategy, and then executing manufacturing technology demonstration projects across the industry, this public-private partnership is advancing the development, implementation, and adoption of more efficient and rapid manufacturing capabilities, including PAT, while also working to ensure that a skilled workforce is available to help realize the vision of intensified processing and real-time release of products (9).
References
1. D. Richardson, presentation at the Collaborating for Continuous Manufacturing Workshop (Washington DC, 2019).
2. FDA, “Accelerated Approval Program,” FDA.gov, Dec. 20, 2020.
3. J. Gardner, “5 Trends to Watch at the FDA in 2020,” FDA.gov, Jan. 9, 2020.
4. G. Zhou and C.-y. Chen, “Industrial Applications of Asymmetric Synthesis,” Comprehensive Chirality (2012).
5. S. Buziol, J.C. Menenzes, and S.T. Santos, “Bioprocess Development and Qualification: PAT-Based Stage 1 and 2 Acceleration Strategies,” www. bioprocessintl.com, Feb. 6, 2020.
6. M. Beccaria and D. Cabooter, Analyst 145 (4) (2020).
7. D. A. Vargas et al., TrAC Trends in Analytical Chemistry 131 (2020).
8. FDA, “Emerging Technology Program,” FDA.gov, Oct. 10, 2020.
9. ISPE, “Change & New Realities Set the Stage,” ISPE.org, Oct. 28, 2019.