Cell culture processes that are used today for the expansion of mesenchymal stem (or stromal) cells (MSCs) have not changed significantly since the first cell therapies were investigated. Typically, with these legacy media systems, cells are seeded at a relatively high density and then allowed to grow. With a slow cell doubling (replication) time of approximately 30 hours, it is necessary to exchange the media twice before sufficient cells are produced for harvesting and further expansion.
In addition, in order to encourage MSCs, which are adherent cells, to adequately attach to the cell culture substrate, an expensive coating often must be applied to the culture surfaces prior to seeding. In smaller vessels, the cost of the coating isn’t that noticeable, but, at large scale, it has the potential to impact the feasibility of commercialization.
Furthermore, media used for research-scale MSC cell culture cannot be used for GMP manufacture for clinical and commercial therapies. In fact, GMP-ready media may come from an entirely different supplier. Even when research and GMP media are provided by the same company, they often function differently, requiring more process development. Similarly, legacy media are designed specifically for MSC cell culture in flatware or bioreactors, and thus, when processes are transferred from 2D plasticware to 3D bioreactors, different media must be used. Each of these requires additional costly process development work.
Consequently, MSC cell culture performed in the traditional manner with legacy media is typically a lengthy, tedious, and expensive process.
Recognizing the limitations of these legacy systems and seeking a means for facilitating efficient and cost-effective MSC therapy development and manufacturing, RoosterBio developed an “MSC ecosystem” including a fit-for-purpose media platform and human MSC (hMSC) cells.
The MSC media platform offers many advantages over the legacy media that is used for MSC cell culture. Cells replicate much more quickly and can be harvested sooner without the requirement for media exchanges, reducing the time and cost for cell expansion. Higher quantities of cells are generally produced, despite the reduced process times. When the recommended processes are employed, no surface coating is necessary for efficient cell attachment, eliminating the cost of the coating and the time needed to apply it.
Figure 1: Scalable 2D MSC Processes from Bench to Pilot to Commercial
Scale-up is simplified as well. The research and GMP grades of RoosterBio’s MSC media operate the same. Cell therapy developers can use lower-cost research-grade material for process development with confidence that the GMP-grade media will provide the same results for the production of clinical material without the need for further optimization (Figure 1). In addition, the media is optimized for both 2D and 3D cell culture processes (Figure 2).
Figure 2: Scalable 3D MSC Processes from Bench to Pilot to Commercial
Overall, RoosterBio’s media developed specifically for MSC cell culture eliminates many of the “hidden” costs associated with legacy cell culture media while providing higher yields. Avoiding media exchanges means less media consumption and waste generation. Requiring fewer passages also involves less labor and affords a reduced risk of contamination. Raw material and waste handling costs and the time to produce the cells — and therefore the cost to rent the manufacturing suite — are also reduced. As an added bonus, the cells are ultimately healthier, because they are kept in culture for a shorter period of time.
Realizing the benefits of RoosterBio’s fit-for-purpose MSC media does require use of the recommended protocols. This is a premium media system when compared to conventional cell culture media on the market, and simply replacing that media and running the same protocols will not provide the benefits described above. It is essential for cell therapy developers to trust the RoosterBio process to reap the maximal benefits from the media.
At lab scale, legacy processes require thawing cells, plating them onto coated plates, performing two media exchanges in a row three days apart, harvesting the expanded cells, splitting them, and repeating. When using RoosterBio media, cells are thawed and plated onto uncoated plates and then harvested and split after four or five days with no second passaging step, unless a larger quantity of cells is required. Despite the shortened protocol and less time spent in the lab, the result is a higher yield of healthier cells. The cells are handled less, about half the media is consumed, and the time to product is reduced by a third or more. The result is significant time and cost savings despite the higher cost of the specially engineered media.
The fact that the media has been specifically engineered for MSC cell culture is the basis of its high performance. The same approaches, expertise, and insights used to optimize cell culture processes themselves were applied to the development of a media optimally suited for MSC cell culture.
The driver for the development of this fit-for-purpose media was the recognition that, with existing media, a tremendous quantity of media is needed to produce a sufficient number of doses of an MSC therapy, making manufacture in typical bioreactors not feasible. RoosterBio’s goal is to help MSC therapy developers advance their products through development and commercialization so they can positively affect patient lives. Solving this problem was thus crucial.
Most media suppliers aren’t willing to invest the time and resources needed to develop an optimum cell culture medium. RoosterBio did, even though such a product allowed each customer to use less media. Applying bioengineering and bioprocessing expertise led to the development of media for MSC cell culture that does more than simply not kill the MSC cells — it is designed to enable optimal cell growth. The initial focus on performance in bioreactors led to the development of media that allows for seamless transition from 2D flatware to 3D bioreactors, while the focus on clinical success led to the development of research-grade media that perform the same as GMP-grade products.
The end result: a bioengineered MSC media platform that affords much more efficient, cost-effective, and industrializable manufacturing processes that generate healthy cells — as confirmed by extensive post-expansion cell characterization.
As with any other technology employed in the manufacture of biologic drug substances and drug products, it is recommended that the MSC media platform be adopted as early in the drug development process as possible. The later the development stage, the higher the cost to implement a change, owing to the need to demonstrate equivalency in the process, although RoosterBio is open to help clients at all development stages.
When the RoosterBio media is paired with RoosterBio MSC cells, which are well characterized and manufactured using tightly controlled processes, a certain level of expansion is guaranteed, depending on the specific process. The intent with the MSC ecosystem is to help MSC product developers with an end-to-end manufacturing solution.
In addition to the cell culture media, RoosterBio also offers upstream genetic engineering–focused media and downstream extracellular vesicle (EV) collection media. hMSCs are a clinically relevant cell source for extracellular vesicles (EVs), such as exosomes, which have been shown to be potent and able to elicit similar responses to whole hMSCs. The optimal hMSC manufacturing process enables hMSCs to be turned into an optimal EV manufacturing cell, because MSCs are the cell type with the most highest therapeutic relevancy for exosome production. Consequently, the RoosterBio MSC media platform has applications beyond MSC expansion and could be the foundation for the industrialization of exosome generation.
Additionally, while RoosterBio remains focused on MSCs, the concept should work equally well with other types of cells, even if they have different requirements, including induced pluripotent stem cells (iPSCs), T cells, and so on.
MSCs as cell therapies and a source of other drug substances, such as EVs, are a disruptive technology and, consequently, will have a fairly extensive life cycle. As the market expands, the demand for cost-effective, efficient, and high-yielding MSC culture processes will grow exponentially.
The RoosterBio MSC platform, including both specially designed cells and media, allows MSC cell therapy developers to invest their intellectual capital on formulation development and clinical studies, rather than on the raw materials and the manufacturing process.
The fit-for-purpose media, regardless of whether used with RoosterBio MSCs or others, allows for reduced resource consumption and waste generation during the production of higher quantities of healthy cells in much less time, all of which adds up to a lower cost per cell. It also enables seamless scale-up from research to commercial GMP production, including the transfer of processes from 2D flatware to 3D bioreactors.
Figure 3. Comparative Results for the RoosterBio Cell-Culture System
Comparative studies performed for 2D and 3D culture process using the RoosterBio media and protocol and various commercially available conventional media and corresponding protocols clearly demonstrate the benefits of the RoosterBio media platform (Figure 3). No other media on the market offers such a quantified value proposition.
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