Remembering Raw Material Basics for mAb Production

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Quality control for biologic production often begins at the starting materials. For monoclonal antibody (mAb) production, this includes the cell line, the media, the buffers, and other components that launch the cell culture process in upstream processing. However, even the development of mAbs is growing more complex as R&D efforts illuminate new ways that diseases can be targeted and, thus, treated. As such, taking a step back and re-evaluating the basics of mAb production, beginning at the start of the line, may be beneficial for the biopharma industry as a whole.

Back to basics

Going back to basics, mAb developers and biomanufacturers need to consider: when sourcing raw materials and biochemicals for mAb production, what are the first things to look out for?

According to Fang Tian, PhD, director, Biological Content, ATCC, there are three main things that should be initially considered, particularly by a biomanufacturer, when sourcing raw materials and biochemicals for mAb production:

• quality of the raw materials
• traceability of the raw materials
• reliability of the supplier and its quality system.

Angela Johnson, executive leader, Global Regulatory & Compliance, Cytiva, points out that the first thing a biomanufacturer should look out for is “identifying how the raw materials can be used in the manufacturing process—keeping in mind both near-term and long-term regulatory goals—so that internal quality subject matter experts (SMEs) can have a clear and early line to supplier’s quality organization.”

Johnson matches Tian’s assertion, stating that, from a quality and supply chain perspective, “a biomanufacturer should look at their suppliers’ quality systems, traceability, control of variability, and collaborative technical support.”

Compared to traditional drug manufacturing, mAbs production involves a comparatively complex and costly manufacturing process that often faces significant changes during technology transfer and scale-up for cell culture steps, especially when going from clinical scale (<2000 L) to commercial scale (>15,000 L), Johnson explains. Because of this complexity and cost-risk, quality relationships between biomanufacturers and suppliers should be developed early in the process. “This can reduce compliance risks and save weeks to months of time in preparing documentation to reach biopharmaceutical manufacturer regulatory milestones,” says Johnson.

Johnson also emphasizes the importance of keeping in mind that raw materials used in upstream processing for cell culture should have validated sources of purity and quality, and that expression systems (Chinese hamster ovary [CHO], murine myeloma cells [NS0], PER.C6, etc.) should be sourced from reputable suppliers. She also points out that the International Council for Harmonisation (ICH), in its Q7 Good Manufacturing Practice, Q8 Pharmaceutical Development, Q9 Quality Risk Management, and Q10 Pharmaceutical Quality System guidelines (1), has stipulated stringent requirements regarding product quality, and that monitoring the working groups and periodic updates to key standards impacting manufacturing processes is an important element of mAb regulatory strategy throughout multi-year clinical development and commercial manufacturing lifecycles.

“When sourcing raw materials, there are several things to consider, but most importantly one must consider the quality of the raw material,” says Philip Schaefer, head of Business Franchises, Process Solutions, MilliporeSigma, reinforcing what both Tian and Johnson say. “Many vendors have tiered levels of quality. For production of mAbs, raw materials should be of a quality that meets the current regulations,” Schaefer states.

Schaefer goes on to further explain that, in order to confirm the quality of raw materials, one needs to compile a vast amount of information from one’s suppliers to ensure that the raw materials and components purchased continue to meet the technical, regulatory, and supply needs for their designated use and function. “This can be resource- and time-intensive, as well as expensive,” Schaefer cautions.

Testing raw materials/biochemicals

Validating the quality and safety of raw materials requires analytical testing. As Johnson says, all starting and source materials used in the growth and maintenance of host cells should be adequately controlled. Both FDA guidance and harmonized international recommendations from ICH and the World Health Organization (WHO) address these issues with raw material sourcing, she adds. “Reliable sourcing and quality documentation for starting cell lines is important. For cell banks, methods, reagents and media used, date of creation, quantity of the cell bank, in-process controls, and storage conditions [are] also critical,” Johnson says.

Meanwhile, for other raw materials, Johnson notes that the most basic and mandatory tests required would include verification of the identity of the raw material using analytical methods suitable for the specific chemical; this could include methods specified by compendial monographs or other analytical methods such as Fourier transform infrared or Raman spectroscopy. Additional testing for chemical purity could include inductively coupled plasma mass spectrometry, liquid chromatography, or liquid chromatography–mass spectrometry.

“It is also important to consider the impact of biological factors such as endotoxin and bioburden which may come with some raw materials. It is helpful to understand the origin and general manufacturing process for these raw materials to mitigate risk. This applies to all animal origin materials, as well as potentially other organic materials. Animal origin materials should always be screened for mycoplasma and viruses, as a minimum,” Johnson says.

Authentication of cells lines is “foundational for scientific research and developing accurate data, as well as avoiding misidentification, duplication, or cross-contamination,” says Tian, who explains that cell-line authentication is done using two basic assays:

• Short tandem repeat (STR) typing, the first method, is the standard used for intraspecies identification of different cell lines of the same species so they can be separated. The STR method applies to human cell lines and mouse cell lines.
• Cytochrome oxidase 1 (CO1) barcoding, the second method, is designed for interspecies identification to determine if there is cross contamination of cell lines from different species.

“Contamination of cell cultures from mycoplasma, a bacteria, is rampant and difficult to detect,” Tian also points out. The two different mycoplasma tests that are commonly conducted to detect or rule out contamination are polymerase chain reaction-based mycoplasma testing, which is rapid and sensitive, and direct culture-based mycoplasma testing, which is considered the gold standard and most commonly accepted by FDA, the European Medicines Agency, and other global regulators for biological drug lot release, Tian says.

Tian notes, however, that the focus should not be on the numerous, specific tests needed to ensure the purity of raw materials and other upstream processing components, but rather on the use of biological standards and certified reference materials within these analytical tests because their incorporation provides the highest level of quality assurance, accuracy, and traceability, all of which increase researchers’ confidence that their results are reliable and reproducible.

“For raw materials such as buffer, media, and supplements, it is important to have comprehensive testing that mitigates variability and inconsistencies that could lead to performance, yield, and quality issues,” adds Schaefer. “Whether the trace metal is intentional in the media formulation or an impurity, trace components have different effects and ‘ideal’ concentrations may vary according to the process in question. To avoid product quality issues, it is vital that biopharma and biosimilar companies understand the effect of elemental metals on a given bioprocess, and quantify the impurities present in their processes.”

Schaefer also emphasizes the importance of microbial testing, another essential analysis that can minimize risk. “Testing for endotoxin, bioburden, and mycoplasma in materials derived from fermentation, plant, or animal sources is essential. This testing can also be included on synthetic and chemically based raw materials to further mitigate risks,” Schaefer says.

Johnson, meanwhile, further elaborates that upstream processing components that are aggregated, blended, or hydrated by an external supplier have their own set of requirements, which are based on the use and quality attributes of that component. “Media or supplements should be assessed for consistency and performance. Qualitative measurements could include pH, osmolality, and performance assessments based on growth and/or product titer. Analytical testing could include endotoxin, bioburden (for powder), and measurements of components such as glucose or amino acids,” she says.

To be more specific, buffers have a primary chemical function, so analytical measurements of pH, conductivity, buffering capacity, and endotoxin should be performed, Johnson enumerates. She adds, “identity testing could include a panel of the analytical testing profile, as well as tests for specific ions of molecules in the buffer using wet chemistry, ion chromatography, liquid chromatography, etc.” Furthermore, antibody critical reagents are crucial to regulated good practice (GxP) drug development assays. “Poor quality reagents risk generating inaccurate and unreliable results, while failure in supply can delay preclinical and clinical studies. Overall, there are potential serious consequences in losses in time, resources, and reputation if quality is not established early in the process,” Johnson asserts.

Best practice tips

Establishing best practices for procuring and testing of biochemicals and raw materials would benefit a company just starting out in mAb production. Tian says that best practices for any company would include ensuring the use of high-quality, traceable raw materials and to incorporate certified reference materials within that company’s procurement and testing processes. Just as important, biological standards and reference materials should be obtained through a credible source from the beginning and during testing, Tian also notes.

“This is essential in today’s bioproduction environment as biomaterial validation is now required by the National Institutes of Health for grant funding and by a number of scientific journals. Additionally, regulatory agencies requires validation of all materials included in investigational new drug and clinical trial applications,” Tian states.

Tian further adds that, although mAb production has been the major focus for many years and has well-established procurement and testing methodologies, the trend is now shifting toward cell and gene therapies. “The demand for standards and reference materials is accelerating in these newer areas indicating that these companies are striving to establish best practices as well,” she observes.

Best practices recommended by Johnson include:

• partnering with suppliers and labs that understand the biopharma market and regulatory space specific to mAbs
• leveraging suppliers as much as possible to keep resources focused on manufacturing
• developing an effective panel of tests that rapidly facilitate raw material release
• ensuring a regulatory roadmap and monitoring of changes in manufacturing guidance and standards throughout development and the commercial lifecycle.

Meanwhile, Schaefer points out that an often-overlooked best practice is to include high-quality raw materials early in development. “When starting out, it is important to be forward-looking and select raw materials that can easily transition to scaled-up processing. It is also important to have a quality agreement in place with raw material suppliers, including change notification. Having these things in place early in the sourcing of raw materials can add value to one’s supply chain and assist in the development of in-house quality management systems.”

The high titer challenge

Nowadays, with high titer mAb production resulting from the optimization of upstream cell culture processes, newer challenges emerge.

“As we push our mAb production systems harder and higher, it becomes more important than ever to minimize raw material variability that can affect outcomes,” Johnson says. “This makes chemically defined media more desirable, reducing the lot-to-lot variability.”

This effort to minimize raw material variability puts more focus on the low levels of impurities that can impact cell culture, such as trace metals at parts per million and parts per billion levels, low levels of organic impurities, and variation in endotoxin levels, Johnson continues. “The ability to identify these factors and control them throughout the mAb production cycle is critical to high-titer, intensified processes,” she states.

Schaefer says that one of the biggest challenges in mAb production is keeping up with the regulatory requirements because these can change overtime. “We leverage our biopharma and pharma regulatory intelligence and participation in industry associations to stay abreast of constantly evolving regulatory requirements so we can advise and support our customers accordingly,” he says.

Johnson goes on to agree, noting that “Changes in standards, or regional guidance, or even training of our qualified person (QP) and auditors can impact the overall success, time, and complexity of mAb development. We participate in both industry partnerships and our in-house regulatory team works directly with mAbs developers, allowing us to keep up to date with changes that impact customers—the best regulatory intelligence allows us and customers to be proactive rather than reactive.”

Meanwhile, scalability and manufacturing remain an issue in mAb production. For many years, high titer mAb—and vaccine—production has been a game changer in the prevention and treatment of many diseases, especially because their manufacture can be done on such a large scale, says Tian. However, she points out, the production of vaccines is often limited by low-yielding manufacturing processes. Similarly, the development of newer categories of therapeutic, such as gene therapies, is constrained during large-scale production (e.g., the scale up of viral vector production).

In summary, when dealing with modern-day production challenges in the upstream processing stage for mAbs, taking a step back and getting back to the basics is itself a good practice. As the molecular complexity of newer biotherapeutics continues to grow and yields are continually optimized, establishing or re-affirming basic best practices in sourcing and testing raw materials can help maintain product purity, safety, and regulatory compliance.

Reference

1. ICH, Quality Guidelines. www.ich.org/page/quality-guidelines, accessed Oct. 9, 2023.

About the author

Feliza Mirasol is the science editor for BioPharm International.

Article Details

BioPharm International
Volume 36, No. 11
November 2023
Pages: 16–18, 33

Citation

When referring to this article, please cite it as Mirasol, F. Remembering Raw Material Basics for mAb Production. BioPharm International 2023, 36 (11), 16–18, 33.