Commercial production biopharmaceuticals

Figure 4.9 Scale-up of proposed biopharmaceutical production process to generate clinical trial material, and eventually commercial product. No substantive changes should be introduced to the production protocol during scale-up...

In preparing the latest edition of this textbook, I highlight the latest developments within the sector, provide a greater focus upon actual commercial products thus far approved and how they are manufactured, and I include substantial new sections detailing biopharmaceutical drug delivery and how advances in genomics and proteomics will likely impact upon (bio)pharma-ceutical drug development. 

The world s population continues to grow and the average life expectancy continues to increase. Pharmaceutical and biopharmaceutical products are more in demand as the population expands, requiring novel and specialized medications to treat common and debilitating diseases. The industry is challenged to rapidly discover and commercialize products to treat existing unmet medical needs and emerging threats as viruses mutate into new diseases that threaten the stability of the world as we know it. 

The recombinant DNA technology of Cohen and Boyer enabled them to generate the first commercial product in 1978 human insulin expressed in Escherichia coli. These efforts also led to the first biotech company on 15 October 1980 Genen-tech went public on the New York Stock Exchange. Fascination about this modern biopharmaceutical and the huge potential of the new biotechnology caused the stock price to jump from US 35 to 89 in the first 20 minutes by the evening of the same day, the market capitalization was US 66 million ... 

Since the first product, the recombinant kallilcrein inhibitor ecallantide (KALBITOR , Dyax, USA), was approved by the FDA in 2009, several more followed, mainly being peptides and small proteins. Antibodies and fragments thereof are currently in clinical trials awaiting approval [154]. Several more biopharmaceutical products such as insulin, interferon-alpha 2b, and hepatitis B vaccine are on the market in India and other Asian countries [155]. Apart from biopharmaceuticals, a range of industrial enzymes, among them phytase, nitrate reductase, or lipase, are commercially available. Direct information on the production process is mostly not available, but it can be concluded from journal and patent literature that mostly the AOXl promoter is used in these cases, and other expression systems like the GAP promoter are applied as well. In total, approximately 70 products are on the market, and a list can be found at http // www.pichia.com/science-center/commercialized-products/ [156]. 

As well as overcoming many of the inherent problems associated with agriculture, plant tissue culture also offers a number of advantages over conventional animal cell culture methods currently being applied to produce biopharmaceutical proteins commercially [8], As plant culture media are relatively simple in composition and do not contain proteins, the cost of the process raw materials is reduced and protein recovery from the medium is easier and cheaper compared with animal cell culture. In addition, as most plant pathogens are unable to infect humans, the risk of pathogenic infections being transferred from the cell culture via the product is also substantially reduced. 

In this review, we focus on the use of plant tissue culture to produce foreign proteins that have direct commercial or medical applications. The development of large-scale plant tissue culture systems for the production of biopharmaceutical proteins requires efficient, high-level expression of stable, biologically active products. To minimize the cost of protein recovery and purification, it is preferable that the expression system releases the product in a form that can be harvested from the culture medium. In addition, the relevant bioprocessing issues associated with bioreactor culture of plant cells and tissues must be addressed. 

The physicochemical and other properties of any newly identified drug must be extensively characterized prior to its entry into clinical trials. As the vast bulk of biopharmaceuticals are proteins, a summary overview of the approach taken to initial characterization of these biomolecules is presented. A prerequisite to such characterization is initial purification of the protein. Purification to homogeneity usually requires a combination of three or more high-resolution chromatographic steps (Chapter 6). The purification protocol is designed carefully, as it usually forms the basis of subsequent pilot- and process-scale purification systems. The purified product is then subjected to a battery of tests that aim to characterize it fully. Moreover, once these characteristics have been defined, they form the basis of many of the QC identity tests routinely performed on the product during its subsequent commercial manufacture. As these identity tests are discussed in detail in Chapter 7, only an abbreviated overview is presented here, in the form of Figure 4.5. 

Figure 5.8 Typical industrial-scale fermentation equipment as employed in the biopharmaceutical sector (a). Control of the fermentation process is highly automated, with all fermentation parameters being adjusted by computer (b). Photographs (a) and (b) courtesy of SmithKline Beecham Biological Services, s.a., Belgium. Photograph (c) illustrates the inoculation of a laboratory-scale fermenter with recombinant microorganisms used in the production of a commercial interferon preparation. Photograph (c) courtesy of Pall Life Sciences, Dublin, Ireland...

Table 5.10 Various products (non-biopharmaceutical) of commercial significance manufactured industrially using microbial fermentation systems...

Immunoassays have found widespread application in detecting and quantifying product impurities. These assays are extremely specific and very sensitive, often detecting target antigen down to parts per million levels. Many immunoassays are available commercially, and companies exist that will rapidly develop tailor-made immunoassay systems for biopharmaceutical analysis. 

In contrast to the biopharmaceuticals discussed thus far (recombinant proteins and gene therapy products), antisense oligonucleotides are manufactured by direct chemical synthesis. Organic synthetic pathways have been developed, optimized and commercialized for some time, as oligonucleotides are widely used reagents in molecular biology. They are required as primers, probes and for the purposes of site-directed mutagenesis. 

Since the commercial introduction of the P-CAC in 1999, several industrial applications have been shown to be transferable to the system. Moreover, users in the biopharmaceutical and foodstuff industry have seen their productivity increasing dramatically as a result of using the P-CAC technology. Furthermore, a P-CAC has been shown capable of continuously separating stereoisomers when using chiral stationary phases even when there is more than one chiral center in the desired molecule. Below some of the applications are described in more details. Others are proprietary and hence cannot be disclosed. 

Both pre-clinical and clinical trials are underpinned by a necessity to produce sufficient quantities of the prospective drug for its evaluation. Depending on the biopharmaceutical product, this could require from several hundred grams to over a kilo of active ingredient. Typical production protocols for biopharmaceutical products are outlined in detail in Chapter 3. It is important that a suitable production process be designed prior to commencement of pre-clinical trials, that the process be amenable to scale-up and, as far as is practicable, that it is optimized (Figure 2.9). The material used for pre-clinical and clinical trials should be produced using the same process by which it is intended to undertake final commercial-scale manufacture. 

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