The research and development of Cell and Gene Therapies (CGTs) is growing at an unprecedented rate, with seven cell and gene therapy drugs approved by the FDA and 1,200 experimental therapies currently in development.¹
 
As these therapies advance from clinical research to commercialization, the manufacture of CGTs will play an essential role in providing these therapies at scale and ensuring these life-changing therapies reach the patients who need them.
 
Mike Stewart of Matica Biotechnology discusses the role manufacturing will play in advancing the CGT industry, key points of differentiation between in-house manufacturing versus outsourcing, as well as manufacturing processes. –KB 
 
Contract Pharma: What role will manufacturing play in advancing the CGT industry?
 
Mike Stewart: Cell and gene therapies (CGTs) are on the cusp of finally having their day in the sun. Although there are only seven CGT drugs approved by the FDA on the market right now, nearly 1,200 experimental therapies are currently in development.
 
Manufacturing has played – and will continue to play – a significant role in supporting the entire bioecosystem. Taking a new drug from initial discovery to commercialization is a massive undertaking. It requires extensive initial research from academia and biopharma companies, complex clinical trials that involve the participation of hospitals and patients, and the establishment of a stable supply of medicines. As these drugs advance through the process of commercialization, scaling and efficiency will become increasingly important to meet the needs of the patients who stand to benefit from them.
 
Given the nature of CGTs – which are derived from living cells and employ cutting-edge technologies in their development – they stand out as one of the most complex therapeutics, and, therefore, demand customized development and manufacturing processes. Successful, timely development of CGTs will require that the manufacturing effort has staff scientists with ample experience, a robust cell line and viral vector development, and an enduring commitment to quality. 
 
Contract Pharma: What are key points of differentiation between in-house manufacturing and CDMO capabilities?
 
Mike Stewart: On the in-house side, some therapy developers opt for manufacturing their drug themselves because of the level of oversight and control they’re able to quickly exert over the process. Given the bespoke nature of gene therapies, in particular, many developers who opt for in-house manufacturing also believe that keeping operations in-house is the only way to truly tailor the manufacturing process to the needs of that particular therapy.
 
There are certainly instances in which in-house manufacturing is the way to go. However, many CDMOs have a breadth of specialized experience developing different CGTs, which make them better suited to manufacture a therapeutic than the developer. Additionally, having experienced staff, specialized equipment, and facilities ready to go makes CDMOs better equipped to hit the ground running with therapy development. This becomes particularly attractive in terms of reducing overall turnaround times. Having all of these resources on-hand allows CDMOs to behave very flexibly, which bodes well for CGTs as they advance from discovery stage to clinical trials. 
 
Contract Pharma: What are the quality and efficiency benefits of single-use, closed-system manufacturing processes?
 
Mike Stewart: On their own, single-use and closed systems offer many benefits: Both can go a long way toward minimizing contamination concerns and eliminating the need for product changeover between batches, saving production time and personnel resources that would otherwise be spent on sterilization for subsequent batch processing. When combined, the two approaches eliminate open manipulations of the product, and maintain an impermeable environment throughout the entire bioproduction run. This optimized manufacturing process leads to enhanced efficiency, faster timelines and, most importantly, increased safety profiles for the production teams and, ultimately, patients. 
 
Additionally, a properly constructed single-use, fully-closed manufacturing system makes use of sensors and monitors that are integrated into the system, which allow for the periodic sampling of the various culture attributes in real time at critical production segments. Because the system is closed, sampling times are reduced, and do not carry typical contamination risks. This component of the manufacturing process creates real-time, actionable data, which allow for process adjustments that can be made automatically in response to input from the monitoring system. As a result, process efficiency is improved, and product quality is maintained from start to finish.
 
Contract Pharma: What are the critical components of a robust viral vector development process that help to ensure efficient gene therapy development?
 
Mike Stewart: Dependable and efficient viral vector production is critical to the success of emerging gene therapies. Perhaps the most important element to consider in this process is scalability: Given that the manufacturing footprint and process of a discovery-stage gene therapy may not match the same therapy’s manufacturing requirements during large-scale clinical trials, gene therapy manufacturers must have a long-term strategy to ramp up production as needed.
 
Scalability should be a concern throughout gene therapy manufacturing, but especially within viral vector development due to the complexity and fragility of the process. To meet the requirements of various stages of drug development, viral vector manufacturing must be able to:

• Generate a large enough concentration of cells to produce the viral vector
• Purify the finished product to ensure safe and effective administration to patients
• Capture real-time data on the quantity and quality of the product 
• Anticipate possible supply chain disruptions

In addition to scalability, technology transfer – the process of transferring knowledge, expertise, and technology from research laboratories to manufacturing facilities – is another critical component of viral vector manufacturing and should be smooth and efficient to maintain fidelity to protocols and processes that will ensure uniformity and efficacy of the gene therapy. This process can be complex and time consuming and requires careful planning and coordination to ensure process integrity and fidelity as it scales from discovery to clinical scale. 
 
To achieve efficient tech transfer, manufacturers need to exhibit flexibility in process design and platform adoption as the manufacturing process evolves from discovery through clinical and commercial stages. Every effort should also be made to anticipate downstream technology needs and configurations as early as possible, even during the discovery phase. As manufacturing reaches larger scales, conducting facility and process fit assessments prior to initiating the viral vector manufacturing process can help identify and rank any potential gaps in the facility or risks in the process. Lastly, early adoption of single-use technologies can help buffer manufacturing processes and costs against future unknowns.
 
Contract Pharma: What are the emerging assays and analytical methods in CGT manufacturing?
 
Mike Stewart: A few emerging analytical methods in CGT manufacturing, include:

• Molecular assays, such as gene and microRNA (miRNA) expression profiling, have shown promise in assessing cell therapy potency, stability, and consistency. In comparison to existing methods – such as flow cytometry, ELISA or functional assays – gene and miRNA expression profiling require significantly less input material and generate a comprehensive picture of cellular function. This can be extremely invaluable since the efficacy of cell therapies rely on multiple, often incompletely understood, cellular functions such as trafficking, differentiation, antigen presentation, etc. As a result, genomic and transcriptomic assays can be invaluable in assessing not just potency per batch, but also in comparing batch-to-batch potency.

• The gold standard analytical methods for determining the empty/full ratio of gene therapy products have been high-performance liquid chromatography, analytical centrifugation and transmission electron microscopy. However, these methods are costly and laborious – posing challenges in scalability and throughput. As a result, methods – such as charge detection mass spectrometry (CDMS) – are becoming increasingly popular. 

 
CDMS is an emerging form of mass spectrometry that can be used to analyze capsid content through the differences in charge and mass between empty and full capsids. In this approach, the mass of the intact capsid is determined from simultaneous measurements of its mass-to-charge ratio and charge, and then multiplied to yield the mass of the capsid. Measurements are performed for thousands of capsids, and converted into a mass spectrum, with peaks corresponding to empty, partially full and full capsids.
 
References
1. https://www.biospace.com/article/cell-and-gene-therapy-market-size-growth-trends-forecast-report-2022-2030

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Mike Stewart is a manufacturing strategy expert with over 20 years in the viral vector therapy and vaccine production industry. At Matica, Mike leads the company’s technical functions, including process engineering, GMP process development, and assay development. Prior to joining Matica, Mike was the director of manufacturing for Fujifilm Diosynth Biotechnologies, a CDMO providing manufacturing services for virus-based vaccine products. In addition to his three years at Fujifilm, Mike has worked for protein and virus organizations, including Boehringer-Ingelheim Biomanufacturing, Meridian Life Science and St. Jude’s Children’s Research Hospital.