Regulating genetically modified mosquitoes

By Dalia Deak

Fears of spreading zika virus have renewed interest in the use of genetically modified mosquitoes to suppress disease, with recent attention focused on the UK firm Oxitec. Last week, the developing public health crisis around zika prompted the federal government to tentatively clear a small-scale field test for the first time in the United States, pending a public comment process on a draft environmental assessment submitted by Oxitec. It should be noted that a final approval for the trial will not be made until the FDA completes the public comment process.

The genetically modified insects, which are male Aedes aegypti mosquitoes, are designed to breed with the female Aedes aegypti mosquito (primarily responsible for transmitting zika, dengue fever, and other diseases) and contain a gene lethal to their offspring. The female mosquitoes lay eggs but the larvae die well before adulthood. Oxitec claims that recent tests have shown up to a 90% decrease in the population of the Aedes aegypti mosquito, with a recent test in Piracicaba (~100 miles from Sao Paulo in Brazil) showing an 82% decline. Tests have also been conducted in the Cayman Islands and Malaysia.

In the United States, Oxitec is in the process of waiting for FDA approval to conduct trials in the Florida Keys. However, this is relatively unclear and uncharted territory for the federal government in terms of what group should be responsible for the review, and the decision for the CVM jurisdiction in this case remains hotly debated. Jurisdictional debate exists between the U.S. Department of Agriculture and the FDA’s Center for Drug Evaluation and Research (CDER) and Center for Veterinary Medicine (CVM).

Genetically engineered insects developed for pest control purposes are considered under the oversight of the U.S. Department of Agriculture’s Animal and Plant Heath Inspect Service. On the FDA side, the definition of a drug includes an article intended for use in diagnosis, cure, mitigation, treatment, or prevention and/or an article intended to affect the structure or any function of the body of man or other animals. The management of drug review is divided between new human drugs, as administered by the CDER or the Center for Biologics Evaluation and Research (CBER), and new animal drugs (drugs intended for use in animals, other than man) as administered by the CVM. Because the Oxitec mosquito has a disease mitigating function, some have indicated that the mosquitoes should be have the strict requirements of a medical trial that are in place to protect human subjects, including informed consent by all individuals in the release area.

Ultimately, the decision was made that CVM would be responsible for regulating the Oxitec mosquitoes based on CVM’s precedent of regulating other animal sterilants used for animal population control as animal drugs. Because of the importance of intended use in determining regulatory authority, Oxitec has also been careful to define the use of the product as controlling the population of specific mosquitos, with no explicit claim around prevention or mitigation of disease in humans.

However, this determination has not come without significant pushback, particularly from residents of the Florida Keys. The release of the mosquito, while subject to public comment, ultimately will not require the informed consent of residents in the area of release. A petition signed by over 160,000 individuals indicating that the company is using a FDA “loophole” to allow the release of these mosquitoes against the wishes of the residents. Some have even threatened to sue if this goes forward.

The evolving regulatory and legal landscape for these genetically modified mosquitoes, and similar products that may develop in the future, have important implications. It will be interesting to follow and see how they develop moving forward, particularly in the face of heightened concerns around emerging public health crises.



At the end of her fellowship year, Dalia Deak had completed a MPH in the Department of Health Policy and Management at the Harvard T.H. Chan School of Public Health and was accepted Harvard Law School as a JD candidate ('19). She received her BS in biomedical engineering from the University of Virginia, where she focused primarily on computer science in biomedical engineering and issues at the intersection of technology, health policy, and public health. After receiving her undergraduate education, Dalia joined the Brookings Institution as a Research Assistant where she worked on their medical device evidence and innovation portfolio. While at Brookings, Dalia co-authored a report for the U.S. Food and Drug Administration on the implementation of a unique device identification system that would support postmarket surveillance and enhance patient safety. Dalia’s research interests lay at the intersection of medical device and drug policy and public health law, and her fellowship research paper was entitled "Repurposing Transformative Drugs: Public Health, Policy, and Legal Issues."

One thought to “Regulating genetically modified mosquitoes”

  1. Regardless of who does the risk assessment of transgenic mosquitoes, the step by step procedure will be the same. There is no novelty in the assessment or possible shortcuts. The agency doing the assessment can perfectly follow what has been done in Panama, Brazil or Malaysia.
    As for the opposition, there will always be one. But is not a science-based opposition, just as there was no scientific basis in the opposition that emerged in Brazil. Diseases transmitted by Aedes aegypti are so severe that the response to a public pressure with no basis on science facts is plain irresponsibility.

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