The conventional way of determining whether a new drug for dogs works is by testing it on research dogs, ultimately euthanizing them in order to examine the internal effects on their bodies.
In consideration of animal welfare, the U.S. Food and Drug Administration is looking for alternative research approaches that don't require animal testing.
Toward that end, the agency is proposing a study to collect information that would eliminate the need for experimental animals in certain types of research. The study itself does entail the use of 24 dogs, but the dogs would be subject only to "minimally invasive blood sampling" and adopted out as pets afterward, according to a statement by FDA Commissioner Scott Gottlieb, MD.
"In our study, no dogs would be euthanized," Gottlieb says. "Instead, the proposed study would place dogs into three groups and, over the course of several months, they'll receive a total of three pills. After each pill is administered, our researchers will draw a small amount of blood from the dogs at specified intervals to measure the concentration of the drugs in the blood and compare them against existing data for these products."
He continues, "By using the data we generate from these blood tests to establish a clear benchmark for how these drugs are absorbed in the dogs' blood, we expect to be able to use these data to develop informatics tools ..."
With those informatics tools, researchers in the future could model how drugs are absorbed, rather than have to test them on live dogs, he explains.
According to an FDA press release, if the model is validated, the resulting data will be made available publicly. Developers of animal drugs "may use these data to aid in the design of in vitro studies used as an alternative to bioequivalence trials using animal subjects," the agency says. In vitro studies are conducted outside a living body, as compared with in vivo studies, which use living organisms. Bioequivalence pertains to assessing how a formulation of a drug would perform in vivo. Drugs that are bioequivalent have the same biological effects.
Gottlieb notes that the dogs in the proposed study will have plenty of human contact and socialization in advance of the study. "Because we know that it’s important to prepare the dogs to be calm for their blood draws, and to give them a head start on their transition to life as pets, the research staff will work with the dogs to socialize and acclimate them to their environment for at least two months before this study begins," he says. "The dogs will receive regular veterinary care, including vaccinations and other preventive care, so that they remain happy, well-socialized and healthy."
The agency didn't indicate where the dogs would come from. FDA representatives have not been available to answer questions because of a partial shutdown of the federal government since Dec. 22, caused by a budget standoff between the administration and Congress.
The specific goal of the proposed study is to validate a model to evaluate drugs used in combination, where one drug is absorbed systemically and the other is absorbed locally. To test the model, researchers will deploy two well-known and widely used antiparasitic drugs: ivermectin, used to treat heartworm infections; and praziquantel, used for tapeworm infections.
Explaining that "drugs that act locally are not absorbed into an animal's blood stream, while systemically acting drugs are absorbed into the blood stream," Gottlieb says: "For antiparasitic drugs that act locally within the gastrointestinal tract, this has historically required data gathered from terminal studies, meaning the animals were artificially infected with gastrointestinal parasites and then euthanized at the conclusion of the study so that researchers could physically examine the GI tract for parasites or parasite damage, to evaluate whether the drug was effective."
He concludes, "The goal of the model we're aiming to develop is to reduce or eliminate these research practices."
An 11-page concept paper provides technical details on the study. The FDA is accepting public comments on the study proposal through Jan. 15.
Judging from 49 comments posted online by the agency, out of 282 comments submitted to date, the great majority of people support the agency's goal of reducing the need for animal testing in research.