Advanced Therapies: Industry & Regulatory Members Share Perspectives At NIFDS-USP Joint Workshop

By Minkyung Kim, Pharm.D., M.B.A., USP; Kevin Carrick, Ph.D., USP; and Misun Park, Ph.D., NIFDS

USP, in collaboration with South Korea’s National Institute of Food and Drug Safety Evaluation​ (NIFDS), hosted a Joint Workshop on Advanced Therapies​ on Oct. 14–15, 2021. NIFDS is a part of the Ministry of Food and Drug Safety, the South Korea regulatory authority, responsible for improving public health and well-being through scientific safety evaluation of food and drugs. The workshop focused on quality control in advanced therapies. The goal of this workshop was to network with diverse stakeholders – including academia, industry, and regulators – to identify challenges and provide new standards and solutions to help advance product development for advanced therapies.

Multiple regulatory pathways exist for advanced therapies in the global regulatory environment.¹ Although the terminology used to refer to raw materials varies in the global environment (e.g., starting material, sources, components), the need for quality remains. Manufacturing of advanced therapies products is complex, involving many raw materials that may impact the quality of the final product. A strategic approach must be taken for selecting and qualifying raw materials for use, as the quality of the raw material is a key component of assuring product quality.^2,3 On day one of the workshop, the presenters discussed regulatory perspectives on raw materials and advanced therapies, quality control of raw materials, and manufacturing of advanced therapies. On day two, workshop attendees discussed comparability plans and quality control assessment, such as evaluating off-target effects of genome editing tools.  

Regulatory Perspectives: Establish A Valid Rationals To Support Quality Management System

To ensure the safety and efficacy of a product, high-quality raw materials are required. When non-compendial grade materials are used, identifying specifications for them can be challenging; in this case, it is imperative to recognize embedded risks and establish a valid rationale to mitigate expected risks. In particular, the raw material of biological origin (e.g., fetal bovine serum, trypsin, heparin, antibody) may increase the risk of introducing contamination with adventitious agents. Depending on the source of the raw material, an adequate qualification program should be established. Song Hee Park, a reviewer and scientific officer from the NIFDS's Cell and Gene Therapy Product Division, discussed these issues, reviewing regulatory perspectives of raw materials and highlighting the requirement for a quality management system.

USP’s Continuous Commitment To Raw Material Quality

Subject matter experts presented lectures and case studies and highlighted best practices to control and evaluate raw materials. Kevin Carrick, Ph.D., director, and Jerome Jacques, Ph.D., principal scientist at USP Global Biologics, introduced practical approaches to ensure product quality, such as defining failure modes and mitigating risks. USP <1043> Ancillary Materials Used in Cell Therapy Manufacturing introduces a four-tiered system to define risk level and suggests how to conduct risk-reduction activities. Carrick added that USP <1226> Verification of Compendial Procedures can help manufacturers when designing verification of compendial procedures. Several USP general chapters provide stakeholders with methods that can help mitigate risks associated with raw materials, including <92> Growth Factors and Cytokines Used in Cell Therapy Manufacturing, <89> Enzymes Used as Ancillary Materials in Pharmaceutical Manufacturing, and <90> Fetal Bovine Serum — Quality Attributes and Functionality Tests. Jacques reviewed USP activities related to trace metals in media, informing attendees that USP is currently drafting an informational general chapter to provide stakeholders with key considerations and best practices in this area.  

Plasmid DNA is a critical starting material used in the upstream production of many advanced therapies. Lili Belcastro, Ph.D., principal scientist at Bristol Myers Squibb (BMS), stated that several guidances discuss plasmid DNA when used as a drug substance, but there is a lack of regulatory guidance in the manufacturing of cell and gene therapy processes. To begin addressing this issue, USP and BioPhorum are collaborating to define best practices surrounding the use of plasmid DNA. USP has also formed an Expert Panel dedicated to developing a documentary standard containing best practices for plasmid DNA sourcing, qualification, and testing.

Minimize Risk With Strategic Planning: Analytical Comparability

In 2019, USP co-hosted a workshop titled “Comparability in Cell and Gene Therapies” with the Alliance for Regenerative Medicine (ARM) to discuss challenges in demonstrating comparability and potential solutions (e.g., establishing a constructive comparability plan). Building off the outcomes from the 2019 workshop,⁴ discussions from the NIFDS-USP workshop continued to emphasize the criticality of demonstrating a robust comparability strategy for regulatory applications. 

Scott Burger, M.D., founder and principal of Advanced Cell & Gene Therapy, noted the importance of confirming the comparability of raw materials when they are sourced from multiple suppliers. He stressed the importance of ensuring the quality of research-grade raw materials and bovine-derived components and, if possible, avoiding the use of research-grade raw materials, which can lead to regulatory actions such as a clinical hold.⁵ Ideally, raw materials should be GMP-manufactured. When research-grade materials must be used, they must be qualified with further testing. Additionally, animal-derived materials should be avoided to minimize risks. Burger added that manufacturers should double-check terminology because the definition of primary and secondary animal-origin-free varies by supplier. Burger encouraged manufacturers to contact the FDA early to help evaluate development plans. Holding a pre-meeting with the FDA or a scientific advice meeting with the EMA can help address questions about whether materials are adequate to qualify.

KyungDong Bae, Ph.D., executive director, Helixmith, presented the transition process from small lab scale to commercial production. Bae mentioned that, as product development progresses, process change and/or adjustment are inevitable, and comparability testing is a critical aspect of development in the context of current industry practice. He emphasized establishing a qualified small-scale model before process characterization and using process performance qualification (PPQ) to obtain valid scientific evidence about product quality and to ensure the consistency and reproducibility of the commercial process. He stated that during a series of changes in process, understanding the product’s critical quality attributes (CQAs) for comparability is essential because patients are most impacted by safety and efficacy.

Mo Heidaran, Ph.D., vice president, Parexel, also addressed significant risks posed by changes in the manufacturing process, which can lead to changes in product quality. Heidaran reiterated essential aspects of establishing analytical comparability through the assessment of CQAs-before and after major changes to manufacturing using well-defined and predetermined acceptance criteria, sampling plans, statistical tools, and qualified assays. For gene-modified cellular products, Heidaran encouraged using approaches that minimize donor-to-donor variability. For example, manufacturers can divide the donor material to perform a side-by-side comparison of one process at two facilities or two different processes in the same facility.

Methods To Control Raw Material Quality: Cell Contamination Detection, Genetic Stability, Mycoplasma Control, & Off-Target Analysis

Due to the nature of advanced therapies, it is necessary to evaluate the safety and quality control throughout the entire product life cycle, from raw materials to final product. In particular, when cells or genetically modified products containing a gene editing process are used as raw materials, it is essential to assess characteristic analysis and quality control in the manufacturing process. The Advanced Bioconvergence Product Research Division in NIFDS continues to conduct preemptive regulatory science research to develop new technology-based evaluation methods for advanced therapies' safety and quality control. During the workshop, NIFDS introduced several emerging approaches that resulted from these efforts to control the quality of raw materials with increased sensitivity and accuracy, such as cell contamination detection, characteristic analysis, mycoplasma detection, and the assessment of genetic stability and off-target genes after genetic alteration.

Kyeung Min Joo, M.D., Ph.D., from Sungkyunkwan University reviewed new tools for quality control assessment of raw materials. Joo showed the effect of long-term in vitro culture on genetic alteration and reviewed the high sensitivity of array comparative genomic hybridization (aCGH) and whole exome sequencing (WES) compared to karyotyping. He stressed that during long-term culture, manufacturers should exercise caution about the potential for new genetic alterations such as deletion, duplication, and mutation and their tumorigenic potential. Additionally, Joo compared the sensitivity of detecting cell-contamination via short tandem repeat (STR) profiling, mitochondrial DNA (mtDNA) heteroplasmy, DNA methylation, and single nucleotide polymorphisms using next-generation sequencing (NGS-SNP). He recommended STR profiling over NGS-SNP due to its higher sensitivity.

Genetic stability is another important component of quality control, as it ensures genetic integrity upon cell division via accurate transmission of all genetic information to daughter cells. Disruptions to genetic stability, which are characterized by chromosome instability, copy number alterations, and nucleotide changes, can lead to cancer development or loss of cell function. The event can occur when any changes are made during production processes, such as during the characterization of a cell line (e.g., master cell banks, end of production, and working cell banks). These were explained by Myungshin Kim, M.D., Ph.D., from Catholic University. She introduced and showed the results of various genetic stability analyses, such as karyotyping, fluorescence in situ hybridization (FISH), microarray, and NGS. Kim pointed out the importance of identifying a variation from the primary cell line and detecting any changes made throughout the manufacturing process to ensure genetic stability.

Mycoplasmas are a common cause of serious contamination in cultured cells. Ja-Lok Ku, D.V.M., Ph.D., from Seoul National University reviewed the quality control of cell lines, mycoplasma contamination in cell culture, the eradication of mycoplasma, test methods and detection kits for detecting mycoplasma contamination, and mycoplasma testing of cell lines included in the USP-NF, highlighting <63> Mycoplasma Tests in particular. He also shared his experience in managing the Korean Cell Line Bank. He said it is critical to form a cell line bank to supply appropriate materials. The essential aspects of controlling cell line quality are checking cell viability, mycoplasma testing, and DNA fingerprinting analysis. He recommended choosing the optimal mycoplasma contamination test method by comparing several methods. Also, STR analysis is vital for the authentication of cell culture.

Hyoungbum Henry Kim, M.D., Ph.D., from Yonsei University reviewed off-target analysis for genome-editing-based gene therapy products and discussed the quality assessment approach. Quality control of genome engineering is critical as it can cause severe problems, such as unintended mutations, deletions, insertions, and/or translocations. Kim summarized whole genome sequencing, targeted deep sequencing, and unbiased methods. He mentioned that combining two unbiased methods or conventional techniques with a state-of-the art technique could be one of the best ways to identify off-target effects.

Conclusion And Next Steps

USP continues to maintain close collaboration with regulatory authorities to identify challenges and solutions, thereby accelerating the closure of existing gaps. As discussed at this workshop, there are significant challenges to developing and manufacturing advanced therapies. Raw materials present many challenges, from sourcing and acceptance testing to lot-to-lot replacement. Scale-up and the associated comparability exercises are critical elements to successful product development and must be appropriately planned and executed. USP is working to provide best practices and tools for manufacturers to apply to raw materials. USP will continue working to explore new strategies to safeguard the quality of emerging therapies.

References

1. Drago D, Foss-Campbell B, Wonnacott K, Barrett D, Ndu A. Global regulatory progress in delivering on the promise of gene therapies for unmet medical needs. Mol Ther Methods Clin Dev. 2021;21:524-529.
2. Atouf F. Cell-Based Therapies Formulations: Unintended components. AAPS J. 2016;18(4):844-848.
3. USP. Ancillary Materials for Cell, Gene, And Tissue-Engineered Products <1043>. USP-NF. Rockville, MD: USP; Nov 1, 2020.
4. USP and ARM. Comparability in Cell & Gene Therapies Workshop Final Report & Summary. 2019. https://alliancerm.org/wp-content/uploads/2019/07/ARM-USP-Comparability-Workshop-Final-Report-vFinal-11jul19.pdf.
5. Wonnacott K, Lavoie D, Fiorentino R, Mclntyre M, Huang Y, Hirschfeld S. Investigational new drugs submitted to the Food and Drug Administration that are placed on clinical hold: the experience of the Office of Cellular, Tissue and Gene Therapy. Cytotherapy, 2008; 10(3): p. 312

About The Authors:

Minkyung Kim, Pharm.D., M.B.A., is a scientific affairs manager at USP, APAC. She holds her licenses as a registered pharmacist in the state of Pennsylvania and South Korea. Kim leads global cell and gene landscaping projects to identify opportunities and challenges for product development; distinguish global, regional, and local key opinion leaders; and create a network for further collaboration. Before joining the USP, she worked at Mundipharma and Bayer as a medical science liaison leading advisory boards for immunology and oncology products and deploying diagnostic validating platforms for various companion diagnostics. Her work experience also includes research at the National Cancer Center in South Korea.

Kevin Carrick, Ph.D., is a director of science & standards in USP’s Global Biologics Department. Carrick and his team work with the five USP Expert Committees and multiple expert panels in the area of biologics to develop standards that support biopharmaceutical quality assessment. These standards include documentary and physical reference standards for a wide variety products, from proteins to cell and gene therapies. Prior to joining the USP, he worked at ProMetic BioTherapeutics as the associate director of product characterization and at the American Red Cross as group leader for protein characterization.

Misun Park, Ph.D., is a director of the Advanced Bioconvergence Product Research Division at the National Institute of Food and Drug Safety Evaluation (NIFDS) in Korea, with more than 10 years of experience as a scientific officer and reviewer. Prior to recently re-joining the NIFDS, she worked as an associate research scientist at Columbia University Medical Center. Also, she served as an assistant professor at the Cell Biology and Molecular Medicine Department in the New Jersey Medical School of the University of Medicine and Dentistry of New Jersey. Her research is focused on regulatory science in advanced therapies as well as stem cell-based cardiac cell therapy.