Cell Culture, Single Use, and the Evolving Biopharmaceutical Landscape

Advances in modern medicine have shifted the pharmaceutical market dynamics. As the industry moves towards targeted therapies, drug molecules are becoming more complex, requiring highly specialized manufacturing process.

“Historically, you have had blockbuster drugs for a broad patient population,” says Andrew Bulpin, executive vice president of EMD Millipore’s Process Solutions Business. “But now, it’s the niche buster era, with smaller patient populations. Ultimately, we are heading towards stratified medicines as our understanding of disease mechanisms improves and we get more sensitive and sophisticated in testing for the different biomarkers,” explains Bulpin in an exclusive interview with Pharmaceutical Technology.

Innovation in manufacturing technologies continues to play a key role in ensuring that biopharmaceutical drug products are produced flexibly, economically, and, more importantly, in compliance with the required safety and quality standards.

“The industry continues to evolve along two fronts,” observes Bulpin. “Let’s start in the upstream space.”

“In cell culture, one always has to look at what you are putting into the media,” says Bulpin. “In the past, there were no qualms about putting in fractionated proteins or components of animal origins. Fetal bovine serum, for example, was commonly available.” However, following cases of mycoplasma contamination in the 1970s, endotoxin concerns in the 1980s, and bovine spongiform encephalopathy scares in the 1990s (1), the industry started paying closer attention to the origin of raw materials used in drug manufacturing processes and began moving away from media and reagents of animal origin. “While you may still see some legacy processes using animal serum, all the new ones are animal origin free,” Bulpin notes.

“With the second-generation media, they took away the animal origin component, but they were still not defined,” says Bulpin. “Now you have the third-generation media, which are completely chemically defined and you have full traceability of all the components within the media. This is where most of the major manufacturers are heading, if they aren’t already there.”

Bulpin stresses that in today’s cell culture processes, “it’s all about knowing what’s in the media chemically; it’s all about control; it’s all about traceability.”

The other big focus in biopharmaceutical manufacturing is yield (g/L), adds Bulpin. “Yield is going to be a product of a specific productivity of an individual cell multiplied by the number of cell, i.e., the cell density,” he explains. “There is a lot of work being done on engineering new and different cell lines that have higher individual specificity-this is one area where people are focusing. Another area is looking at cell lines that are more robust and easier to grow in defined media.”

The past decade has witnessed significant improvement in upstream processes such that yields produced are now significantly higher. “To give you an example, the first-generation biopharmaceutical drugs were expressed in an order of 200mg/L,” says Bulpin. “With the new expression platforms, the new drugs coming out can be up to 5g/L, which is a 25-fold increase of productivity or yield out of the bioreactor. Manufacturers can now obtain the same amount of antibodies using smaller-scale 1000-L single-use bioreactors, as was historically produced in 15,000-L stainless steel bioreactors. Single-use is, therefore, suitable for production applications today.”

This increase in upstream efficiency, however, has brought new challenges to downstream purification steps. Because of higher cell densities coming out from the bioreactor, clarification can be a challenge, observes Bulpin. With most high-density processes, the clarification step will often involve centrifugation at some stage. “But for those who want to go purely to single use, and not invest in capital equipment such as centrifuges, one option is to use flocculation treatment,” says Bulpin. Incorporating feed pretreatment, flocculation, and different filtration technologies such as tangential flow filtration into the harvesting and clarification steps can help improve process capacities and filtrate quality (2).

Moving further downstream, protein A chromatography is one of the more expensive processing steps, and “the notion of having it as single-use is still a bit far off,” according to Bulpin. “Current options will be continuous processing, where you have multiple column systems, and I think that will be an area for further exploration moving forward.”

Another trend that bodes well with single use is the increasing number of multiproduct facilities. “Historically, you would have a production facility built for a single product,” notes Bulpin. “But with lower demands in the absolute quantities of antibodies because of the diversity of patient phenotypes coupled with higher yields, manufacturers are looking to have multiproduct facilities, and that is why we see an uptake in single use.”

“There are also other factors that work in favor of single use,” Bulpin adds. “As companies start out on their drug development journey, they tend to want to keep hold of their molecule and take it as far as they possibly can. Because single use is far less capital intensive compared to stainless steel, it enables small companies and start ups to stay in control of their molecules at the early stages, before either investing in the full capital or taking their molecule to a third-party CMO to do larger-scale production.”

Furthermore, in certain geographies, the local governmental policy requires that for a molecule to be sold in that market, the company must do some manufacturing activities in that country. “In the past, the dynamics of doing a big capital production that is going to cost 1 billion relative to the potential market size has put people off,” explains Bulpin. “But now you can do one of these modular approaches, where you put in a single-use facility, and really all you need is a shell of a building and utilities such as electricity and water.” According to Bulpin, EMD Millipore recently expanded its facility in South France, which is fully single use, due to high demand. The company converted the warehouse building into a new production unit. “From start to finish, the installation took four months,” says Bulpin, “to give you an idea of how quickly you can set it up with single-use.”

References

1. L.E Madigan et al., BioPharm Int Supp 22 (4) 2009.

2. S. Le Merdy, BioProcess Int 12 (9) 10–12 (2014).