Plant-derived biopharmaceutical

The extraction and purification of proteins from organisms or biological tissue can be a laborious and expensive process, and often represents the principal reason why vaccines and other therapeutic agents reach costs that become unattainable for many. Downstream processing also can be a major obstacle with respect to cost for large-scale protein manufacturing in plants. However, purification from plant tissues, while still costly, is in general less expensive than purification from their mammalian and bacterial counterparts. Indeed, some plant-derived biopharmaceuticals, such as topically applied monoclonal antibodies, may require only partial purification and thus be even less intensive in terms of labor and cost. 

Plant-Derived Biopharmaceuticals as a Defense AGAINST Biological Warfare Agents... 

A few plant-derived biopharmaceutical products have now reached advanced clinical trials, and the regulatory process has been developed... 

Since risk analysis plays an important role in public policy decision making, efforts have been made to devise a means by which to identify, control, and communicate the risks imposed by agricultural biotechnology. A paradigm of environmental risk assessment was first introduced in the United States by Peterson and Arntzen in 2004. In this risk assessment, a number of assumptions and uncertainties were considered and presented. These include (1) problem formulation, (2) hazard identihcation, (3) dose-response relationships, (4) exposure assessment, and (5) risk characterization. Risk assessment of plant-made pharmaceuticals must be reviewed on a case-by-case basis because the plants used to produce proteins each have different risks associated with them. Many plant-derived biopharmaceuticals will challenge our ability to define an environmental hazard (Howard and Donnelly, 2004). For example, the expression of a bovine-specihc antigen produced in a potato plant and used orally in veterinary medicine would have a dramatically different set of criteria for assessment of risk than, as another example, the expression of a neutralizing nonspecihc oral antibody developed in maize to suppress Campylobacter jejuni in chickens (Peterson and Arntzen, 2004 Kirk et al., 2005). 

The potential of flow of plant-made biopharmaceuticals into the human food chain remains. For example, plant-derived pharmaceuticals could cross-contaminate foodstuffs by spontaneous growth of transgenic crops in areas outside the intended field, or by pollen flow between some plants such as corn. It has been suggested that plant-derived biopharmaceuticals should be generated in nonfood crops, such as tobacco. However, food crops produce the greatest opportuitities for efficient production since they are among the most well-studied of crops. This continues to make them more feasible for edible vaccine production. 

There are a number of steps that can be taken in the construction of plant-derived biopharmaceuticals in transgenic plants that would effectively reduce gene silencing (De Wilde et al., 2000). These are explained in the following sections. 

Explores the development of clinical trials utilizing plant-derived biopharmaceutical proteins... 

The production of secretory antibodies in plants represents an important opportunity for the commercialization of plant-derived biopharmaceuticals. Planet Biotechnology is developing two additional secretory antibodies. RhinoRx is under development for the treatment of colds due to rhinovims, which represents about half of aU common colds and over 20 million doctors office visits a year. For the prevention of doxombidn-induced hair loss (alopeda) - a disturbing side effect for cancer patients undergoing chemotherapy - Planet Biotechnology is developing DoxoRx. Each year in the US, over 250000 patients receive chemotherapy that results in hair loss. 

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