Pharming (genetics)

Pharming is a merger of "farming" and "pharmaceutical" and refers to the use of genetic engineering to insert genes that code for useful pharmaceuticals into host animals or plants that would not otherwise express those genes. As a consequence, the host animals or plants then make the pharmaceutical product in large quantity, which can then be purified and used as a drug product. Some drug products and nutrients may be able to be delivered directly by eating the plant or drinking the milk. For example Golden rice has been developed which contains Beta-carotene in minute amounts. Another potential product would be milk that already has vitamin D in it; this has yet to be realized.

The products of pharming are recombinant proteins or their metabolic products. Drugs made from recombinant proteins potentially have greater efficacy and fewer side effects than small organic molecules (which are often screened as potential drugs) because their action can be more precisely targeted toward the cause of a disease rather than treatment of symptoms. Recombinant proteins are most commonly produced using bacteria or yeast in a bioreactor, but pharming offers the advantage to the producer that it does not require expensive infrastructure, and production capacity can be quickly scaled to meet demand. It is estimated that the expense of producing a recombinant protein drug via pharming will be less than 20% of the current cost.

In the United States, Transgenic plants including but not limited to those which produce pharmaceuticals, are regulated by three government agencies which comprise the Coordinated Framework for Regulation of Biotechnology established in 1986.

USDA Animal and Plant Health Inspection Service - evaluates potential agricultural impacts such as gene flow and 'weediness'
EPA - evaluates potential environmental impact intergenic microorganisms under the Toxic Substances Control Act
DHHS Food and Drug Administration (FDA) - evaluates human health risk if the plant or one of it's proteins is intended for human consumption

Pharming in Mammals

Expression in the milk of a mammal, such as a cow, sheep, or goat, is a common application, as milk production is plentiful and purification from milk is relatively easy. Hamsters and Rabbits have also been used in preliminary studies because of their faster breeding.

Pharming in Plants

Arabidopsis is often used as a model organism to study expression in plants, while actual production may be carried out in maize, rice, potatoes, tobacco, flax or safflower. The advantage of rice and flax is that they are self-pollinating, and thus gene flow issues (see below) are avoided. However, human error could still result in pharm crops entering the food supply. Using a minor crop such as safflower, or a non-food crop such as tobacco, avoids the greater political pressures and risk to the food supply involved with using staple crops such as maize or rice.

Controversy over Pharming

Those opposed to pharming fear that through either mishandling or gene flow, potentially dangerous pharmacauticals may inadvertently enter the food supply. Precedents involving non-pharmaceutical genetically modified crops include the Starlink controversy, and trade war over genetically modified food between the European union and the USA. A similar reaction to pharmed rice is feared from Japan.

In 2002, ProdiGene was fined $250,000 and ordered by the USDA to pay over $3 million in cleanup costs after allowing a fraction of a bushel of volunteer pharm corn to comingle with the soybean crop later planted in that field. Although the chance of gene flow between species is claimed to be low and there was in this case no threat to consumers, the USDA has a zero tolerance policy. ProdiGene has since revised its protocols and resumed operations in Nebraska. In 2005, Anheuser-Busch threatened to boycott rice grown in Missouri because of plans by Ventria Bioscience to grow pharm rice in the state. A compromise was reached, but Ventria has withdrawn its 2006 permit to plant in Missouri due to unrelated circumstances. The company's field trials in North Carolina are expected to continue.

List of companies and products

Please note that this list is by no means exhaustive.

Agragen - docosahexaenoic acid and albumin in flax
Chlorogen, Inc. - cholera, anthrax, and plague vaccines, human serum albumin, interferon for liver diseases including hepatitis C, elastin, 4HB, and insulin-like growth factor in tobacco chloroplasts
Dow Chemical Company - anti-cancer antibodies
Epicyte - spermicidal antibodies in corn
Genzyme - antithrombin III in goat milk
Iowa State University - unknown product in corn
MacIntosh & Associates, Inc. - unknown product in peas
Meristem Therapeutics - Lipase, lactoferrin, plasma proteins, collagen, antibodies (IgA, IgM), allergens and protease inhibitors in tobacco
Pharming - C1 inhibitor, human collagen 1, fibrinogen (with American Red Cross), and lactoferrin in cow milk
Planet Biotechnology - antibodies against Streptococcus mutans, antibodies against doxorubicin, and ICAM 1 receptor in tobacco
PPL Therapeutics - Alpha 1-antitrypsin for cystic fibrosis and emphysema in sheep milk
ProdiGene - aprotinin, trypsin and a veterinary TGE vaccine in corn
SemBioSys - insulin in safflower
Syngenta - Beta carotene in rice (this is "golden rice 2")
University of Arizona - Hepatitis C vaccine in potatoes
Ventria Bioscience - lactoferrin and lysozyme in rice
Washington State University - lactoferrin and lysozyme in barley

Projects known to be abandoned

Large Scale Biology (bankrupt) - using Tobacco mosaic virus to develop patient-specific vaccines for Non-Hodgkin's lymphoma, Papillomavirus vaccine, parvovirus vaccine, alpha galactosidase for Fabry disease, lysosomal acid lipase, aprotinin, interferon Alpha 2a and 2b, G-CSF, and Hepatitis B vaccine antigens in tobacco
Monsanto - abandoned development of pharmaceutical producing corn

References

Biotech firm puts off rice crop here But company says it plans to sow next year. St. Louis Post-Dispatch. April 29, 2005. Pg. A3.
Biotech potato provides hepatitis vaccine. The Atlanta Journal-Constitution. February 15, 2005. Pg. 3A.
Biotechnology Venture Hits Unexpected Snags. New York Times. November 23, 2001. Pg. 5.
Canadian scientists make insulin from plants: 'Bio-pharming' poised to meet huge diabetes demand at less cost. The Ottawa Citizen. February 27, 2005. Pg. A1.
GM corn set to stop man spreading his seed. The Observer. September 9, 2001. Pg. 1.
Pharming plans transgenic first. Financial Times. May 3, 2005. Pg. 18.
USDA says bio-crop safeguards are tighter ProdiGene is back in Nebraska with test plot. Omaha World Herald. June 2, 2004 Pg. 01D
Release Permits for Pharmaceuticals, Industrials,Value Added Proteins for Human Consumption,or for Phytoremediation Granted or Pending by APHIS as of March 29, 2006. ^*

External links

Pharming (genètica) | Pharmapflanze

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