Squirrel monkeys from an Food and Drug Administration nicotine study are headed to a long-term sanctuary after officials concluded that the experiment, which resulted in four deaths, did not meet the agency's animal-welfare standards and shut it down.

Twenty monkeys that were involved in the study, plus six that were not, will be moved to the sanctuary, the FDA said Friday. It did not detail where the monkeys will go or when, although officials said the transition process could be lengthy.

The agency has hired independent investigators to assess its overall animal program and created an “Animal Welfare Council” to provide centralized oversight of animal-research activities and facilities, Commissioner Scott Gottlieb said in a statement.

Officials suspended the controversial squirrel-monkey study last September after renowned British primatologist Jane Goodall called the research “cruel and unnecessary” and “shameful” in a letter to Gottlieb. A  team of veterinarians and other FDA experts visited the agency's National Center for Toxicological Research in Jefferson, Ark., where the study was underway, to check on the animals' welfare and review documents related to the experiment.

The officials found a lack of adequate oversight and “repeated” deficiencies by the contractor taking care of the animals, the FDA said Friday. It also released documents related to the review. Three of the monkey deaths were related to complications from anesthesia administered when catheters were inserted, and “one was related to bloat, the cause of which is often unclear,” the agency said.

The study, which began in 2014, tested how different doses of nicotine affect addiction, especially in adolescents. Adolescent and adult squirrel monkeys were trained to press a lever to give themselves infusions of nicotine. Once the animals were addicted, scientists could see how they reacted to decreasing levels of the drug.

Goodall was enlisted in the fight by the White Coat Waste Project, an advocacy group that says its goal is to publicize and end taxpayer-funded animal experiments. A year ago, the organization obtained 64 pages of documents on the FDA's nicotine-addiction research under the Freedom of Information Act.

Gottlieb said Friday that the FDA is working to accelerate the adoption of various modeling and technology tools to reduce the need for animal testing. But some experiments still require research with primates, he added, including those involving the development of  childhood vaccines.

Anthony Bellotti, White Coat Waste Project’s president and founder, praised the FDA's move and said the group will  “continue to push for more transparency about wasteful spending on taxpayer-funded animal experiments.”

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