Regulatory issues for plant-made pharmaceuticals and vaccines.

Recombinant plant systems potentially offer economic alternatives to produce large amounts of pharmaceutical proteins, including those used in subunit vaccines. Plant systems also provide a convenient oral delivery option, overcoming the cost and inconvenience of purification and injections. The production of pharmaceutical proteins in transgenic plants is tightly regulated, with the US Department of Agriculture focusing on containment of recombinant material and the US Food and Drug Administration focusing on the production system as it relates to manufacture of the drug or vaccine. Current regulations for the production of plant-made pharmaceuticals are to prevent recombinant proteins from entering the food chain or from persisting in the environment, and to guard against recombinant nucleic acid sequences entering genomes of food or feed crops, or wild species. Several alternative plant production systems are being developed. Each system has its strengths and weaknesses with regard to the economics of production, options for alternative routes of administration, authenticity of products and ease with which the production system can be contained. Risk assessments can be used as a means to quantify risks of inadvertent human or environmental exposure to plant-made pharmaceuticals. Several technologies are being tested that reduce the probability of plant-made pharmaceuticals, or genes encoding them, escaping production sites.