US Regulation of Plant-made Biopharmaceuticals, Part 1

Projections for new and existing biopharmaceutical drugs indicate that demand will soon overwhelm supply.¹ New facilities housing cell-culture units can be built, but they require a substantial capital investment and are costly to operate. In response, alternative production systems are being developed. One of the most promising systems incorporates transgenic plants as the expression host.^2-5

The plant-made biopharmaceutical (PMB) industry began in the early 1990s, and a few products are now in advanced clinical trials. Some products that have been produced in plants include trypsin, aprotinin, therapeutic monoclonal antibodies, therapeutic enzymes, protective antigens from human pathogens, and blood factors.^6,7 The regulatory process has developed alongside this growth. An important document on biotechnology regulation was a 1984 Federal Register Notice (FRN), "Proposal for a Coordinated Framework for Regulation of Biotechnology,"⁸ in which the government determined that biotechnology products could be regulated effectively under existing statutory authorities and regulations and described those authorities.

This two-part article will guide you through the matrix of federal agencies, laws, and regulations that govern the evaluation, production, and distribution of the final PMB products derived from recombinant plants. Such products fall under the authority of FDA, the US Department of Agriculture (USDA), and the Environmental Protection Agency (EPA), depending upon the nature of the product and its intended use.

TECHNICAL BACKGROUND

Recombinant organisms are integral to the biomanufacturing industry as a host system for expressing therapeutic and medicinal proteins. Transgenic plant systems promise lower production costs since plants can be grown in a field instead of a cell-culture facility. Also, they provide an alternative production system for proteins that are difficult to express in traditional cell culture.

Using plant-specific transformation techniques, the gene encoding the therapeutic product is inserted into the genome of the host plant. Depending on the techniques and type of plant used, the product may be expressed in the leaves, stems, seeds, fruit, or other plant parts. The recombinant plant is propagated, and a seed bank is established. Subsequent generations of plants are grown from the seed bank to produce plant material expressing the protein, which is harvested and subjected to an extraction and purification process similar to traditional processes with cells or microorganisms.

A PMB is no different than a biopharmaceutical derived from cultured mammalian cells or microorganisms. Existing regulations ensure the safety, purity, and efficacy of a biopharmaceutical regardless of the host expression system. However, with a new host and a new propagation environment (a field or greenhouse which is less controlled than a bioreactor), understanding the differences in development and production is critical for laying the groundwork and defining the regulatory path to commercialization.

PMBs are generally protein products intended for use as human or animal drugs, medical devices, vaccines, diagnostic reagents, and raw biochemical or industrial materials. This article discusses the regulation of biological products for human use as drugs or therapeutics that have been derived from a recombinant plant source. We do not cover traditional "botanical products" as the term is used by FDA in "Guidance for Industry: Botanical Drug Products."⁹ That document specifically excludes "materials derived from genetically modified botanical species (i.e., by recombinant DNA technology or cloning)."

Biological products from any source are unique and must be handled in a different manner than synthesized chemical drugs in order to assure the safety, purity, and potency of the drug. These products are derived from living systems, are heat labile, are subject to microbial contamination, can be damaged by shear forces, and have the potential to be immunogenic or allergenic.

The source material entering the purification process is likely to be generated in a non-sterile environment (a field or greenhouse) and is exposed to unique environmental factors such as agricultural chemicals, weather, insects, birds, mammals, dirt, pollen from other plants, fungi, and bacteria. Also, there are known and unknown potential contaminants that must be identified and analyzed for potential effect on the end product's quality.

THREE REGULATORY BODIES

Because part of the biopharmaceutical manufacturing process takes place outside of a contained facility, a critical component of PMB regulation is a system to avoid inadvertent release of material, to ensure environmental safety, and to protect the integrity of agricultural plant products intended for food and feed. Three US government agencies address these quality and regulatory issues.

The Food and Drug Administration. FDA regulates biologics and drugs that are intended for diagnostic, preventative, or therapeutic use in humans. There are now more than 30 biotechnology (recombinant DNA derived) products approved as therapeutics or vaccines for use in humans.¹

The US Department of Agriculture. USDA regulates the introduction of new plants into the environment, including biotechnology-derived recombinant plants and plant products. All new recombinant plants - referred to as genetically engineered (GE) - are considered regulated articles with the potential to be a plant pest or noxious weed. They cannot be imported to the US, moved, or grown in the environment until a permit or notification is obtained from USDA.

In 1987, USDA issued its first FRN describing the permit process for introduction and movement of GE plants.¹⁰ In 1993, USDA established a notification process and data requirements for requesting deregulated status for a GE plant.¹¹ In 1997, the simplified requirements and process for notifications were updated.¹² These procedures expedited the application and approval of movement and field-release permits for crops expressing certain classes of genes - those similar to genes and protein products for which safety and environmental impact data have already been collected and proteins that were previously deregulated when produced in a different crop.

Over the past 20 years, 60 transgenic plants have achieved deregulated status from USDA and approximately a dozen petitions are currently in review.¹³ However, GE plants expressing a PMB are not eligible for deregulated status and require a full permit (not notification) for import, interstate movement, or field release.

Environmental Protection Agency. EPA regulates molecules that are used in the environment as insecticides, fungicides, herbicides, baits, and rodenticides. Recom-binant plants have been genetically engineered to express molecules or proteins that provide inherent pest or herbicide resistance, including Liberty Link corn, canola and cotton from Bayer Crop-science, Roundup-Ready crops, BollGard cotton, and YieldGard corn from Monsanto. EPA is involved in regulating the production of the PMB if the host plant contains a pest- or herbicide-resistance trait that is genetically engineered into the plant. EPA regulates the expressed molecule that provides the pest resistance as if it is a pesticide and regulates the new use of a herbicide if not registered for use at specified concentrations or with the crop or plant.¹⁴

DESCRIPTION OF REGULATORY FRAMEWORK

Statutory authorities, selected regulations, and Federal Register Notices related to PMBs are shown in Table 1. Here are some explanatory notes.

Table 1. Statutory Authorities and Regulations Related to Plant-Made Biopharmaceuticals

A biological product is defined in Section 351 of the Public Health Service Act (PHS Act) as a virus, therapeutic serum, toxin, antitoxin, vaccine, blood, blood component or derivative, allergenic product, or analogous product, or arsphenemine or derivative of arsphenemine (or any other trivalent organic arsenic compound) applicable to the prevention, treatment, or cure of a disease or condition of human beings.¹⁵

A drug is defined in the Federal Food Drug and Cosmetic Act (FFDC Act) as a product used for the cure, mitigation, or prevention of disease of humans or other animals or articles (other than food) intended to affect the structure or function of the body of humans or other animals.¹⁶ The definition also includes articles recognized in the United States Pharmacopeia, official Homeopathic Pharmacopeia of the United States, Official National Formulary, or any supplement to any of them and components of articles meeting the definition of a drug.¹⁶

Products meeting the definition of a biological product are regulated under both the PHS Act and the FFDC Act. Regulations governing the manufacture and approval of drugs and biological products are located in the Code of Federal Regulations (CFR) Title 21 and include: Good Laboratory Practices Regulations (GLP; 21 CFR Part 58),¹⁷ Good Manufacturing Practices Regulations (cGMP; 21 CFR Parts 210 and 211),¹⁸ and regulations governing the approval of drugs and biological products (21 CFR 600-680, 312, and 314).^18,19,20

Under authority of the Plant Protection Act (PPA), the Biotech-nology Regulatory Services Division (BRS) within USDA's Animal and Plant Health Inspection Service (APHIS) regulates biotechnology-derived plants and plant products.²¹ Regulations regarding the movement and environmental release of biotechnology-derived plants are found in 7 CFR Parts 330 and 340.²² Until a science-based determination is made by APHIS, all engineered plants are considered regulated articles and cannot be imported, moved, or grown in the environment without a permit or notification. Engineered crop plants that are intended for food, feed, or fiber can be deregulated after the filing and satisfactory review of a "Petition for Non-regulated Status" that provides APHIS with detailed environmental exposure and effects data. Engineered plants that are created to express proteins that are not intended to be human or animal consumables (PMBs) must obtain a full permit, rather than a notification, for movement or field release and are currently ineligible for deregulated status. Thus, USDA remains involved in the movement and field production of PMB crops throughout the life of the product.²² In January 2004, USDA published an FRN proposing changes to the regulations regarding importation, interstate movement, and environmental release of certain GE organisms.^{23, 24}

EPA must clear the expressed molecule as a pesticide under Section 3 of the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA).²⁵ This clearance involves evaluation of various human health and environmental analyses under Section 408 of the FFDC Act for food safety purposes.²⁶ EPA has issued regulations (40 CFR Part 174) for these pesticide products, referred to as "plant-incorporated protectants."²⁷

The National Environmental Policy Act (NEPA)¹⁴ sets out the requirements for protection of the environment and applies to the manufacture and approval of drugs for humans. In deciding to approve a drug manufacturing process, a release or movement permit, or the deregulation of a plant, FDA and USDA must evaluate the environmental effects. NEPA requires every agency to assess the consequences of its proposed actions on the environment before making an environmentally significant decision and to make that assessment available to the public. Depending on the nature of the molecule expressed in the plant and the environmental analysis, in-depth NEPA analysis may or may not be triggered under federal laws such as the Endangered Species Act. NEPA requires FDA or USDA to consider additional environmental impacts that might be associated with the licensing of a PMB as part of the drug or biologic licensing process.²⁸

The Toxic Substances Control Act (TSCA) of 1976 gave EPA the ability to track industrial chemicals currently produced or imported into the US.^29,30 EPA repeatedly screens these chemicals and can require reporting or testing of those that may pose an environmental or human-health hazard. EPA can ban the manufacture and import of chemicals that pose an unreasonable risk and can control these chemicals as necessary to protect human health and the environment.

If the manufacture, processing, distribution in commerce, use, disposal of a PMB, or any combination of such activities produces a chemical substance or mixture that presents an unreasonable risk of injury to health or the environment, TSCA is invoked. The PMB manufacturer will be required to submit a risk assessment document describing the specific activity or combination of activities that presents such risk and the means to mitigate the hazard and exposure to the environment and human health. The agency then evaluates whether the risk can be prevented or reduced to a sufficient extent by preventative actions.

FDA, which is primarily responsible for the regulation of biopharmaceuticals, has five centers, three of which may be involved with the regulatory process in different aspects. Biological and drug products for humans are regulated by the Center for Biologics Evaluation and Research (CBER) and the Center for Drug Evaluation and Research (CDER). The Center for Food Safety and Applied Nutrition (CFSAN) becomes involved if the crop will be used as a human food source, or could be accidentally mixed with a food crop.

THE FDA APPROVAL PROCESS

Approval of a biological product requires submission of a Biologics License Application (BLA) or a New Drug Application (NDA).

^15,31,32,33

Both applications contain information needed to make an assessment of the safety, efficacy, purity, and potency of the product. The applications also include detailed information on the manufacturing process, quality control procedures, and specifications for accepting inputs and outputs to the process.

In order to study a biological product or drug in humans - to generate data for the BLA or NDA - an Investigational New Drug (IND) application must also be submitted.^19,20,33 These applications and approvals apply to all biologics, whether the product is derived from recombinant plants or other host systems and regardless of which FDA center regulates the product. Documentation submitted to FDA must be generated under GLP, to assure the quality and integrity of the data.¹⁷ The drug manufacturing process must comply with current cGMP, whether production of material takes place in a bioreactor or in a field.¹⁸

We recommend that the company have a pre-IND meeting with the appropriate FDA center before submitting an IND. This meeting, scheduled upon request, may also include USDA representatives and is intended to provide regulatory officials with an overview of the development plans for the product, to discuss preclinical testing issues, and allow them to raise any concerns that may prevent the clinical trials from proceeding. After the pre-IND meeting, the IND application can be submitted.²⁰

The IND application may contain the following types of information that are unique to a PMB product:

1) a description of the host plant and its biology

2) a complete description of the recombinant DNA constructs and methods used to produce the engineered plant

3) a thorough characterization of the engineered plant, including inserted DNA, expressed protein, and quantitation of protein levels in target tissues

4) the seed banking system, data, and specifications for qualifying the seed, including assessment of the genetic stability

5) procedures for production and confine-ment of the plant material, especially to prevent pollen movement and inadvertent commingling of plant material with other crops intended for food or feed.³⁴

In addition to the plant-specific information discussed above, the application includes the usual chemistry, manufacturing, and controls information for the product. Enough information must be submitted on the manufacturing and testing to allow FDA to assess whether the plant production, purification process, or testing presents a safety concern for patients in the initial clinical trials. The format, roughly described in Figure 1, is spelled out in 21 CFR Part 312.23.³⁵

Figure 1. Components of an IND

THE USDA APPROVAL PROCESS

Developers and manufacturers of PMB products must obtain USDA permits for import, interstate movement, and testing or production of PMB plant material in the field no matter how small or large the acreage. The permits are approved, issued, and managed by the BRS office within APHIS. These PMB permit applications may involve review by CFSAN, CDER, or CBER prior to approval. A record of pending and issued permits can be found on the BRS website.

¹³

The permit application requires information similar to an IND.

1) detailed molecular biology for the inserted genetic material

2) type, function, and use of the expressed protein

3) protein level in plant tissues

4) characteristics of the host system (habitat, persistence, growth)

5) experimental design and confinement strategy

6) potential effects to non-target organisms, humans, wildlife, and the environment from exposure to material approved for release.

Fill this out on Form 2000, which is available from USDA.³⁶

USDA-APHIS regulations are based on the principle of confinement with the goal of minimizing environmental impact and maximizing non-target organism safety. Confinement means that measures must be taken to prevent workers, the environment, and commercial products for animals or humans from inadvertently being exposed, by mixing or dispersion, to the engineered plant and plant products. The permit process requires submission of detailed plans and procedures to ensure confinement and preparation of a document addressing the safety and potential environmental impacts of the GE organism. These are embodied in the permit and in standard operating procedures for shipping, field production, monitoring, and processing. Critical controls, planning, and training are also part the field permit conditions. A critical control plan anticipates risks, defines critical steps in the field production process, and outlines an immediate, effective response to unintended events that might compromise confinement procedures. Figure 2 provides a detailed overview of the APHIS permit process.

Figure 2. USDA-APHIS Permit Process

Permit applications for interstate movement are reviewed and approved in approximately 60 days provided all sites are approved, USDA-inspected facilities. If not, an applicant should allow an additional 30 days for the inspections. Field release applications are reviewed and approved within 120 days of receipt of a complete and accurate application.

Approved permits are issued with supplemental requirements that are specific to the particular plant host, gene product, location, experimental design, acreage, and end use. For example, GE tobacco expressing a PMB must be separated by at least a half-mile from other tobacco fields; however, GE corn expressing a PMB must be isolated by a minimum of one mile from other cornfields. The USDA-APHIS website publishes a list of supplemental permit conditions.³⁷ Approved permits are generally valid for up to one year, and they are renewable upon amendment of the existing permit just as long as the permit does not introduce a new state or a new host plant. ?

ACKNOWLEDGEMENTS

The authors would like to acknowledge Steve Ripley and Astrid Szeto of CBER for their help in locating old Federal Register documents used in the article.

REFERENCES

1. Chovav M, et. al. Q-Series: the state of biomanufacturing. Compiled by UBS Investment Research. 2003 20 June; Available at:

www.ubs.com/investmentresearch

2. Flinn J, Zavon J. Green plants as biofactories for drugs. BioPharm International 2004 Aug; 17(8):42-49.

3. DePalma A. Is a green plant in your manufacturing future? BioPharm International 2003 Nov; 16(11):24-33.

4. Schillberg S, et al. Antibody molecular farming in plants and plant cells. Phyto-chemistry Reviews 2002; 1:45-54.

5. Russell DA. Feasibility of antibody production in plants for human therapeutic use. In Hammond J, et al., editors. Current topics in microbiology and immunology: plant biotechnology: new products and applications. Vol. 240. Berlin: Springer-Verlag; 1999. p. 119-138.

6. Biotechnology Industry Organization. Plant-made pharmaceuticals: frequently asked questions Available at: www.bio.org/healthcare/pharmaceutical/pmp/factsheet2.asp

7. Ma J K-C, et al. The production of recombinant pharmaceutical proteins in plants. Nature Reviews 2003 Oct; 4:794-805.

8. OST. Proposal for a coordinated frame-work for regulation of biotechnology. Federal Register 1984; 49 FR 50857.

9. FDA. Guidance for industry, botanical drug products. Available at: www.fda.gov/cder/guidance/4592fnl.htm

10. USDA. Introduction of organisms and products altered or produced through genetic engineering which are plant pests or which there is reason to believe are plant pests. Federal Register 1987; 52 FR 115.

11. USDA. Genetically engineered organisms and products; notification procedures for the introduction of certain regulated articles: and petition for nonregulated status. Federal Register 1993; 58 FR 60.

12. USDA. Simplification of requirements and procedures for genetically engineered organisms and products. Federal Register 1997; 62 FR 85.

13. USDA. Current status of petitions and permits. Available at: www.aphis.usda.gov/brs/status/petday.html

14. National Environmental Policy Act of 1969. (Pub. L. 91-190, 42 USC 4321-4347, January 1, 1970, as amended by Pub. L. 94-52, July 3, 1975, Pub. L. 94-83, August 9, 1975, and Pub. L. 97-258, § 4(b), Sept. 13, 1982).

15. Public Health Service Act. Section 351. 42 USC 201.

16. Federal Food Drug and Cosmetic Act. Section 201(g). 42 USC 262.

17. Code of Federal Regulations. Good laboratory practice. 21 CFR Part 58.

18. Code of Federal Regulations 21CFR Parts 210, 211, 600. 21 Part 210 available at: www.access.gpo.gov/nara/cfr/waisidx_02/21cfr210_02.html

Part 211 available at: www.access.gpo.gov/nara/cfr/waisidx_02/21cfr211_02.html.

Part 600 available at: www.access.gpo.gov/nara/cfr/waisidx_02/21cfr600_02.html

19. FDA Modernization Act of 1997, Mod-ernization of regulation. Section 123.

20. Code of Federal Regulations. Investigational new drug application. 21 CFR Part 312.

21. Plant Protection Act of 2000. 7 USC 7701-7758. Available at: www.aphis.usda.gov/ppq/weeds/PPAText.pdf

22. Code of Federal Regulations. 7 CFR Part 330. Federal plant pest regulations, general plant pests, soil, stone and quarry products, garbage.

7 CFR Part 340.Introduction of organisms and products altered or produced through genetic engineering which are plant pests or which there is a reason to believe are plant pests.

23. EPA. Environmental impact statement: introduction of genetically engineered organisms. Federal Register 2004; 69 FR 3271.

24. USDA. Dear permit applicant letter. Available at: www.aphis.usda.gov/brs/pdf/011404.pdf

25. Federal insecticide, fungicide, and rodenticide act. 1996; 7 USC 136a. Available at: www.epa.gov/region5/defs/html/fifra.htm

26. Federal food drug and cosmetic act. Section 408. 21 USC 346a. Available at: www.access.gpo.gov/uscode/title21/chapter9_.html

27. Code of Federal Regulations. Final regulations for plant-pesticides. Title 40 Part 174.

28. Code of Federal Regulations. Environmental impact considerations. Title 21 Part 25.

29. USC Title 15 Part 53. Control of Toxic Substances.

30. EPA. Full text of TSCA available at: www4.law.cornell.edu/uscode/15/ch53.html

31. Code of Federal Regulations. Licensing. 21 CFR Part 601.

32. Code of Federal Regulations. Applications for FDA approval to market a new drug. 21 CFR Part 314.

33. Federal food drug and cosmetic act, Section 505. 21 USC 9. Available at: www.access.gpo.gov/uscode/title21/chapter9_.html

34. FDA. Draft guidance for industry: drugs, biologics, and medical devices derived from bioengineered plants for use in humans and animals. Available at: www.fda.gov/OHRMS/DOCKETS/98fr/02d-0324-gdl0001.pdf

35. Code of Federal Regulations. IND con-tent and format. 21 CFR Part 312.23.

36. USDA. Application for permit or courtesy permit Under 7 CFR 340. Available at: www.aphis.usda.gov/forms/2000.pdf

37. USDA. Release permits for pharm-aceuticals, industrials, value added proteins for human consumption, or for phytoremediation granted or pending by APHIS as of 2004 November 17. Available at: www.aphis.usda.gov/brs/ph_permits.html

Sharon A. Berberich is the senior director, licensing & development at Chloroen, Inc., 893 North Warson Rd., St. Louis, MO 63141, 314.812.8142, fax 314.812.8080, s.berberich@chlorogen.com

Rebecca A. Devine, Ph.D is a consultant, 22 Atwood Ct., Silver Spring MD 20906, 301.871.4300, fax 301.871.4833, devine2@comcast.net; who was formerly associate director for policy at CBER. She is on the Editorial Advisory Board of this magazine.