Bruce Carlson Publisher Kalorama Information
Cell Culture Requirements Are Not Only Growing in Magnitude, but Shifting to Match the Increasing Use of Mammalian Cell Lines
The production of biologic therapies such as vaccines, blood factors, and monoclonal antibodies is based on cell culture—and the products that facilitate cell culture. According to Kalorama Information, these products, which include media, sera, and reagents, represent an expanding market. Worldwide sales exceeded $3.4 billion in 2014, up 8.1% from 2013 sales of $3.1 billion, and are expected to show similar growth in revenues for the next five years.
The demand for cell culture and related products is not just rising, but accelerating, a phenomenon that is reflected in the timing of biopharmaceutical product launches: Since the first biopharmaceutical drug Humulin was launched in 1982 to the beginning of this decade (between 1982 and 2009—a 27 year period), there were 117 biopharmaceutical approvals. That’s an impressive number, but there have been 67 approvals between 2010 and 2014—a four year period. Roughly speaking, biopharmaceutical product launches increased from around 4 to nearly 17 approvals per year.
Biopharmaceutical production is increasing not only through the introduction of novel therapeutics, but also through the introduction of biosimilars or generic biopharmaceuticals, which can be manufactured by several companies. The market for cell cultures is expected to grow rapidly alongside biopharmaceuticals and with significant evolution in culture technology.
Cell Line Trends
Many biopharmaceuticals are produced by bacteria, especially the species Escherichia coli and Bacillus subtilis. E. coli has been studied in microbiology laboratories for many years and was the first organism to have its entire genome mapped. It is inexpensive to cultivate, it replicates quickly, and it serves as a good model organism—that is, it provides an example of how other similar life forms will behave—such as how they grow and reproduce, and what makes them deteriorate or die. Bacterial culture is the workhorse of the biotechnology industry.
Animal cells are much more fragile than yeast and bacterial cells. They are often much larger than microorganisms and live in a collective as part of organs or tissues within complex anatomical systems. Animal cells are held together by a delicate membrane, are more difficult to grow in suspension, and often must grow attached to surfaces. These cells are complex, replicate slowly, require complex nutrients, and do not grow as well at high densities. Animal cell culture is more complicated; thus, it is more expensive than traditional fermentation. The most widely used animal cells are Chinese hamster ovary (CHO) cells.
Certain kinds of cells, particularly epithelial cells, are more robust than others and thus are easier to grow in culture. CHO cells are epithelial cells that were introduced to science in the 1950s. They multiply quickly, are relatively hardy, and grow well in culture.
Cell Culture Media Trends
The increasing use of mammalian cell lines, including versatile and uniquely capable stem cells, in upstream bioprocessing has imposed specific demands on cell cultures: namely, better-defined media. The rising stakes and production levels of companies active in biopharmaceuticals have dictated improved reproducibility or consistency in product; mitigation of the risk of contamination; and the use of culture product more amenable to downstream processing or purification.
Media can be organized into three broad types:
- Chemically defined media not only lack animal-origin components, they also exclude components that lack known chemical structure. Chemically defined media do not contain proteins, hydrolysates, or other components of unknown composition.
- Animal-free media contain no components of animal origin, but are not necessarily chemically defined. For example, animal-free media may contain bacterial or yeast hydrolysates or plant extracts.
- Serum-free media are prepared without the use of animal serum, but they may not be entirely free of serum-derived products. Serum-free media may contain undefined animal-derived products such as serum albumin (purified from blood), hydrolysates, growth factors, hormones, carrier proteins, and attachment factors.
The biopharmaceutical industry’s shift away from animal-derived culture products is expected to continue, particularly given the ascension of mammalian cell lines in biopharmaceutical production. Serum-free media is the more complex composition designed for universal use in culturing mammalian cell lines. Animal-free and chemically defined media formulations are less complex and more defined, but are limited to the cultivation of specific cell types.
Working and Master Cell Banks
Once a biopharmaceutical company obtains a beginning cell bank from a cell culture collection, the company’s scientists will do the work of genetically engineering those cells for particular uses. This work may involve various changes, such as gene amplification or gene duplication, the addition of one or more copies of a gene of interest so that each cell produces more protein. Genetic engineering may also be used to alter an animal cell line’s preferred growing conditions. For example, an animal cell line that naturally prefers to grow attached to a surface can be adapted to grow suspended in liquid, emulating the way bacteria or yeasts grow. Cells can be modified so that they perform post-translational modification of the protein in more desirable ways.
When experimentation has produced an optimal version of the cell line, a master cell bank is created. It will be maintained as the source of all cells used to produce the company’s drug through preclinical and clinical testing and then into commercial sale. Working cell banks are created from the master cell bank for producing batches of product. Each batch will be made by seed stock that came from either another working cell bank or the master cell bank.
A complex set of conditions that affect cell propagation, product yield, and concentration of nutrients, waste, and products must be considered in designing a fermentation process. Of paramount concern are fluid viscosity, momentum, and the sizes of the cells involved.
The performance of a fermentor or bioreactor is governed by thermodynamics (such as the solubility of oxygen in the medium), microkinetics (such as cell growth and product formation), and transport of materials (moving nutrients into the cells and removing waste products). Optimal mixing ensures effective oxygen transfer, heat transfer, and dispersal of materials. Minor deficiencies in circulation of the medium can have major effects on growth and protein production.
Shifts in Productive Capacity
Cell culture production is growing faster in the Asia Pacific region than any place else in the world. In fact, this region’s market share is forecast to increase significantly between 2014 and 2019, climbing to one-fifth of the global market.
New technologies used in cell culture production, in particular single-use disposable production systems, are dramatically lowering building costs of biomanufacturing plants. In the near term, expansion will be seen in Singapore, China, Korea, and Malaysia. In the longer term, biomanufacturing expansion will extend into South America, Eastern Europe, and Africa.
An important driver of the cell culture market is the production of seasonal influenza vaccines, as well as pandemic vaccine candidates. Seasonal influenza vaccines have traditionally been produced using egg-based technology. However, this labor-intensive approach to vaccine development is currently being replaced by cell-culture systems.
Prefluce, the first cell culture-based vaccine, received European approval in March 2011 and was available for the 2011–2012 influenza season in the 13 participating European Union countries. On November 20, 2012, the U.S. Food and Drug Administration approved the use of Flucelvax, which is the first U.S.-licensed (trivalent inactivated) influenza vaccine manufactured using cell culture technology.
Stem cell research will also add to the robust growth of the cell culture market. The growing use and diverse applications of stem cells are having a significant impact on the media market, as companies work to understand how best to optimize their growth. For stem cell applications, serum-free media that lack growth factors, cytokines, or artificial stimulators of proliferation will play an increasingly important role.
Bruce Carlson ([email protected]) is the publisher at Kalorama Information, which provides market research in medical markets. Kalorama recently released “Cell Culture: The Market for Media, Sera and Reagents,” the fifth edition of the company’s market research report on world markets for cell culture media, sera, and reagents. In addition to sizing, projecting, and profiling each of these market segments, the market quantifies the world market’s geographical segments and company market shares.