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What are plant-made pharmaceuticals?
Plant-made pharmaceuticals (PMPs) are the result of a breakthrough application of biotechnology to plants to enable them to produce therapeutic proteins that could ultimately be used by the medical community to combat life-threatening illnesses. In this process, plants themselves become "factories" that manufacture therapeutic proteins. These proteins are then extracted, refined and used in pharmaceutical production. Researchers are currently in various stages of field trials and clinical trials of PMP production. It is estimated that it will be at least three to five years before full commercialization of the first PMP is reached. Plant-made pharmaceuticals are strictly regulated by United States regulatory agencies and differ from traditional commodity agriculture on many fronts. Plant-made pharmaceutical research does not represent a new wave of value-added commodity agriculture.
Why plants?
Since most proteins cannot be chemically synthesized, there are very few options for protein production: mammalian and microbial cell cultures and plants. Using plants to produce pharmaceutical proteins presents several clear advantages.
First, there are significant lower facility and production costs associated with PMPs because the technology is developed in natural, renewable resources such as plants. Second, because PMP growth is not limited to special manufacturing facilities, it will be relatively easy to scale production to meet increased and varied demand. These two factors combined have the potential to provide patients with the benefits of greater and faster access to medicines.
Aside from the potential to increase the accessibility to biotech-based drugs, plant-made pharmaceutical technology offers a safe method to produce pharmaceutical proteins. When producing these proteins in traditional cell cultures, there is an inherent risk of propagating human pathogens or other mammalian contaminants. This is not a risk when developing pharmaceutical proteins in plant factories.
Using plants as factories to produce therapeutic proteins also enables researchers the ability to develop novel and complex molecular forms that could not otherwise be produced in mammalian cell cultures.
How are PMPs produced?
Advances in biotechnology have made it possible to genetically enhance plants to produce therapeutic proteins essential for the production of a wide range of pharmaceuticals - such as monoclonal antibodies, enzymes, and blood proteins. These plants are grown under highly regulated conditions in confined growing environments and are strictly regulated by the U.S. Department of Agriculture (USDA), its Animal and Plant Health Inspection Service (APHIS) and by the Food and Drug Administration (FDA).
After the plants are harvested, they go through a series of processing steps that extract, separate, purify and package the therapeutic proteins. The refined therapeutic proteins are ultimately used as the active pharmaceutical ingredient (API) in many life-saving medicines and are regulated by the FDA.
What kinds of plants are used to produce PMPs?
Plants such as alfalfa, barley, corn, duckweed, rice, safflower and tobacco have received APHIS regulatory permits for field trials. These field trials are aimed at delivering the next generation of essential proteins for life-saving medicines.
Why use plants that also can be used for food crops?
Plants that also can be used for food crops are a natural choice for PMP production because researchers have extensive agricultural knowledge and familiarity of these plants, as well as experience with their growth. Scientists have a vast understanding of genetics, agronomics and the environmental impact these plants have, as well as their composition. This information is crucial in developing methods for confining and managing these plants.
What kinds of diseases will be treated with PMPs?
Plants improved through the use of biotechnology can produce the essential building blocks (therapeutic proteins) for innovative treatments for diseases such as Alzheimer's disease, cancer, chronic obstructive pulmonary disease (COPD), Crohn's disease, cystic fibrosis, diabetes, geriatric and child diarrhea, heart disease, Hepatitis C, HIV, iron deficiency, kidney disease, multiple sclerosis, obesity, rheumatoid arthritis, spinal cord injuries, and many others.
Are PMPs the same thing as "edible vaccines"?
No - though they are closely related, there are some differences. Edible vaccines are also developed through the use of biotechnology, but are not necessarily the same as PMPs. PMPs produce proteins that will be used in the subsequent manufacture of medicines, as the active pharmaceutical ingredient (API) in a pharmaceutical product. Therapeutic proteins produced in PMP field trials are usually not intended to be administered via food. They will be administered orally, enterally or topically. Regulatory oversight coupled with individual companies' stewardship procedures are designed to keep PMPs separate from the food chain so that these proteins are not mixed with or consumed as food.
Edible vaccines, on the other hand, are vaccines produced in food crops, which can be orally administered in proper doses (the whole food will not be consumed). While different from PMPs, they are similar in that neither is to be consumed as part of the food supply, and edible vaccines will be administered only under the supervision of physicians or licensed healthcare workers.
Are PMPs the same as foods and feeds improved through the use of biotechnology?
No. Protein-producing plants simply are "production factories" and are one step in the pharmaceutical manufacturing process and are handled completely outside the commodity food and feed stream. PMPs leverage much of the agricultural biotechnology applications and knowledge used in genetically enhanced food and feed, but for an entirely different purpose and end-use.
Agricultural biotechnology uses advanced plant breeding techniques and tools of biotechnology to introduce beneficial traits to crops grown for food, feed and fiber. Many foods and feeds improved through the use of biotechnology possess beneficial characteristics, such as higher yield, better nutrition and resistance to disease. Examples of agricultural biotechnology for consumption purposes include "golden rice," which produces pro-Vitamin A, and grains with improved oil content.
The science used to produce proteins in plants represents the new era of biopharmaceutical manufacturing and differs from traditional commodity agriculture on many fronts. PMP research does not represent a new wave of value-added commodity agriculture.
The production and handling of pharmaceutical-containing plants is strictly regulated under rigorous federal guidelines for safety of humans and the environment. Pharmaceutical protein-containing plants are grown and processed separately from food and feed crops, a system known as "confinement," or in a completely closed loop system. In addition, only a few select growers are identified, trained and supervised to grow these prescription plants. The seeds are only available from the manufacturer and cannot be purchased off the shelf at a local seed store.
What confinement measures are in place to ensure there is no commingling with food or feed crops?
The production and handling of pharmaceutical-containing plants is strictly regulated under rigorous federal guidelines for the safety of humans and the environment. Pharmaceutical-containing plants are grown and processed separately from food and feed crops - a system know as confinement, or in a completely closed loop system.
Confinement includes procedures to prevent commingling with food or feed crops, the environment, humans and non-target organisms. Confinement procedures are based on scientific risk assessments that evaluate the potential for and impact of exposure, and are modeled after Hazard Analysis and Critical Control Point (HACCP) principles. HACCP is a system currently in use in the food industry and identifies hazards and critical control points, and then establishes procedures for maintaining those points. The PMP industry has named its risk assessment Containment Analysis and Critical Control Point (CACCP).
These risk assessments developed for plant-made pharmaceuticals take into account the crop, the specific protein, the spatial setting or location of the intended production area and agronomic and crop handling practices. Confinement measures include both spatial isolation and temporal separation. Spatial confinement defines the distance between plots for plants producing pharmaceutical proteins and conventional crops used for food and feed. Temporal boundaries define the time separating the flowering and pollination between plants producing pharmaceutical proteins and nearby conventional crops of the same or related species.
Additionally, farm equipment that is used for these types of plants cannot be used for any food or feed crops. The annual training of contract growers and all other individuals involved with the development and production of PMPs is an APHIS regulatory requirement. An APHIS-approved training program ensure personnel are prepared to successfully implement and comply with all permit conditions. Federal regulations are designed to prevent protein-producing plants from crossing paths with crops used for food and feed production, making it highly unlikely for commingling to occur.
Are PMPs currently on the market?
No. Today, researchers are in various stages of field trials and clinical trials of PMP production and it is most likely that it will be at least three to five years before full commercialization of a PMP is reached. In January 2006, the U.S. Department of Agriculture's (USDA) Center for Veterinary Biologics (CVB) gave regulatory approval for the first plant-made vaccine to Dow AgroSciences' Animal Health division and their ConcertTM product, a vaccine to improve animal health. This first U.S. regulatory approval of a plant-made vaccine demonstrates the safety and efficacy of plant-made vaccines.
Permits have been issued in the following 14 states since 2001: Arizona, California, Florida, Hawaii, Iowa, Kansas, Kentucky, Missouri, Nebraska, South Carolina, Texas, Virginia, Washington and Wisconsin.
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