By Robert M. Califf M.D., and Ritu Nalubola, Ph.D.
Recent scientific advances now make it possible to more efficiently and precisely alter the genome of plants, animals, and microorganisms to produce desired traits. These genome editing technologies are relatively easy to use and can be applied broadly across the medical, food and environmental sectors, with potentially profound beneficial effects on human and animal health. However, there are also potential risks ranging from how the technology affects individual genomes to its potential environmental and ecosystem impacts. Additionally, genome editing has raised fundamental ethical questions about human and animal life.
Genome editing technologies can be used to introduce, remove, or substitute one or more specific nucleotides (letters in the DNA code) at a specific site in the organism’s genome, and is achieved with the use of protein-nucleotide complexes. Several classes of these complexes exist, the most recent discovery is known as CRISPR/Cas9.
Research is currently underway that would use these technologies to:
- Treat HIV, cancer or rare diseases by genetically altering specific types of cells;
- Control or alter organisms that carry infectious diseases (for example, mosquitoes that are vectors of viruses/parasites causing dengue fever, Zika or malaria; or mice that transmit bacteria causing Lyme disease);
- Improve the health and welfare of food producing animals, (for example, hornless cattle, pigs resistant to African swine fever or porcine reproductive and respiratory virus); and
- Alter specific traits of food plants or fungi (for example, non-browning mushrooms).
Accompanying the enthusiasm about these promising technologies are questions about whether FDA is prepared to ensure the safety of regulated products that use this technology. Providing appropriate and balanced regulatory oversight for applications involving an emerging technology is not a new or unique challenge for FDA, but the potential breadth of applications and the fundamental nature of altering the genome call for the participation of multiple constituencies in considering the most effective regulatory policies to address any potential risks.
Maintaining product-specific, risk-based regulation
Genome editing applications are relevant to three main FDA-regulated product classes. The specific regulatory approaches for each of these classes vary, reflecting differences in underlying statutory authorities. FDA is maintaining a product-focused, science-based regulatory policy, in accordance with specific legal standards applicable to each type of product and consistent with overarching U.S. Government policy principles.
Human medical products that apply gene editing to exert their therapeutic effect are regulated under our existing framework for biological products, which include gene therapy products. “Gene editing” here refers to non-heritable situations somatic cell gene therapy only, and not to heritable conditions (germ line gene therapy). The FY16 appropriations bill restricted use of federal funds “in research in which a human embryo is intentionally created or modified to include a heritable genetic modification.” FDA’s Center for Biologics Evaluation and Research (CBER) has a well-established program and policies in place to evaluate gene therapy products. Although different types of gene editing have potential clinical applications, currently only one type of gene editing, zinc finger nuclease- (ZFN) mediated, has been announced by their sponsors as being applied in clinical trials underway in the United States. Proposals for NIH-funded human gene therapy clinical trials are discussed and reviewed for scientific, clinical, and ethical issues by the NIH’s Recombinant DNA Advisory Committee (RAC). The RAC recently discussed (and did not find any objections to) the first clinical protocol to use CRISPR/Cas9-mediated gene editing. The potential for “off-target” effects such as insertions or deletions at unintended genetic loci has been identified by experts in the field as a key concern.
Similarly, FDA’s Center for Food Safety and Applied Nutrition and Center for Veterinary Medicine have in place programs to adequately address foods derived from plants produced using genome editing and animals produced using genome editing. In these two product areas, we are issuing documents to clarify our current thinking and seek scientific information. With respect to foods derived from plants produced using genome editing, FDA has a longstanding program for foods derived from new plant varieties, including those developed by recombinant DNA (rDNA) techniques. We are requesting information on whether human and animal foods derived from genome edited plants pose additional risks compared to those from traditionally bred plants. FDA’s decades of experience providing oversight of foods from new plant varieties, coupled with scientific evidence and data received, will help inform our thinking on risk considerations going forward.
When animals are produced using genome editing, FDA has determined that, unless otherwise excluded, the portion of an animal’s genome that has been intentionally altered, whether mediated by rDNA or modern genome editing technologies, is a drug because it is intended to alter the structure or function of the animal and, thus, subject to regulation under our provisions for new animal drugs. We have updated our existing guidance for genetically engineered animals to include genome editing within its scope, and are issuing it in draft form for public comment. We are also seeking input on whether certain types of genome editing in animals pose low or no significant risk, and we may modify our regulatory approach based on this input.
Our efforts to gather necessary scientific data aside, industry remains responsible for ensuring that its products meet all applicable requirements, including safety standards. FDA has historically made itself available to meet with developers and we encourage them to engage with us to help ensure they meet their statutory and regulatory obligations. And we will continue to provide technical advice and guidance for industry, as necessary.
Collaborating with Federal agencies
The White House Office of Science and Technology Policy (OSTP), FDA, the U.S. Environmental Protection Agency (EPA), and the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service (APHIS) initiated an effort in 2015 to ensure public confidence in the regulatory system for biotechnology products and improve the transparency, predictability, coordination, and, ultimately, efficiency of that system. After reviewing public comment to a docket and holding three public meetings, the agencies produced A National Strategy for Modernizing the Regulatory System for Biotechnology Products, to help ensure that the federal regulatory system is prepared to assess future biotechnology products, issued in September; and, earlier this month, a 2017 Update to the Coordinated Framework for the Regulation of Biotechnology (CF Update), to clarify each agency’s role.
APHIS is proposing to revise its regulation regarding genetically engineered organisms that may pose plant pest or noxious weed risks. As FDA, APHIS, and EPA formulate policies, there may be differences in approaches, reflecting differences in the scope of their authorities and the types of risks addressed. Under the CF Update, interagency coordination and cooperation will continue, including on appropriate terminology, identification of hazards, and approaches to addressing risks, within the constraints imposed by regulatory paradigms for different product areas.
FDA also has a longstanding collaborative relationship with the NIH office that oversees the RAC. FDA serves as a non-voting liaison on the committee, hears the discussions first-hand, and receives the written recommendations. These recommendations may be considered during our overall review of investigational new drug applications (INDs) submitted to FDA.
Scientific engagement and horizon-scanning
Being ready to evaluate innovative emerging technologies is a top FDA regulatory science priority. FDA is co-sponsoring two studies, conducted by the National Academies of Sciences, Engineering, and Medicine (NASEM). Both are expected to be completed this year. FDA is also conducting its own horizon-scanning through its Emerging Sciences Working Group, an FDA-wide science-based forum, and opened a public docket to receive input on emerging technologies.
Working with international partners
Scientific advances do not adhere to national boundaries and therefore it is critical that we understand the evolving views of our international counterparts. Given the leadership role of the United States in biomedical and biological sciences, we cannot afford to fall behind in this exciting scientific frontier. As expected, international regulatory agencies, too, are currently working in this area. FDA’s CBER is an active member of the International Pharmaceutical Regulators’ Forum (and its Gene Therapy working group), which provides a forum for members to identify and exchange information on issues of mutual concern and undertake targeted regulatory cooperation activities.
FDA is committed to fulfilling its mission to safeguard public health, while encouraging innovation and competitiveness. The actions we have taken to date, including release of the CF Update, National Strategy, and FDA’s documents – are steps in a series of ongoing activities. We will continue to collaborate with our federal and international partners, and actively communicate with stakeholders to help ensure confidence in FDA’s regulatory system. However, oversight provided by FDA is one aspect of broader governance necessary for safe and responsible research and development of genome editing applications. Moreover, the expansive scope of intentional genomic alterations using modern genome editing technologies has triggered debate on fundamental ethical and social issues, which will continue to influence public opinion and acceptance of genome editing applications. Even as FDA implements necessary steps for effective regulation to ensure the safety of products, the role of broader, inclusive public discussion involving multiple constituencies (e.g., scientists, developers, bioethicists, and public interest and community groups) to address the larger societal considerations should not be overlooked.
Robert M. Califf, M.D., is Commissioner of the Food and Drug Administration
Ritu Nalubola, Ph.D., is a Senior Policy Advisor in FDA’s Office of Policy