New technology aims to minimize animal testing for drug discovery

In order for a new pharmaceutical drug to be approved for clinical use, it has to be tested on multiple laboratory animals first – a practice that many animal activists work hard to prevent.  While rats and other rodents have aided in the development of thousands of drug compounds over the years, many are ultimately euthanized or sacrificed throughout the drug discovery process.

But now, there may be a way to limit the number of animals exploited in the name of medical science.  A novel technology developed by researchers at Empiriko may provide a new way to test therapeutic drug candidates and determine drug safety – without using animal models.

It all revolves around the creation of “chemosynthetic livers,” a newly developed substance that mimics a group of enzymes found in the liver.  According to lead researcher Mukund Chorghade, this new innovation acts as a stand-in for the human liver, an essential organ needed for the distribution of small molecule drugs.

“Whenever we take a medicine, our liver enzymes start acting on that particular drug,” Chorghade, chief scientific officer of Empiriko and president of THINQ Pharma, told “The livers are the organs by which drugs get distributed in the human body, and they are the primary method for excretion, because you don’t want the drug accumulating in your body.”

However, if the liver does not break down a drug properly, it could potentially have toxic effects on the body.  So before researchers can test experimental medications on human subjects, they have to perform a process known as metabolic profiling.

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To conduct this portion of their research, the drug being studied is given to animal subjects first.  Once the experimental compound does its intended job and is broken down by the liver, the researchers must painstakingly detect any trace amounts of molecular byproducts in the body.  Known as metabolites, these “leftovers” are most often responsible for causing unwanted side effects that can ruin an otherwise promising drug candidate.

Although metabolic profiling is a crucial part of the drug research process, it often leads to the death of animal subjects.

“Say you’re testing a compound, and it has to be fed to a rat or a dog.  Then you withdraw samples of the drug from the urine, the saliva and the feces, and then you study the distribution of the metabolites throughout those,” Chorghade said. “The concentrations will be very small, and when you’re done studying them, in many studies, the animals are euthanized at the end of it.”

It’s during this stage of research that the chemosynthetic livers (Biomimiks) come in.  Instead of using animals to test toxicity, researchers can conduct metabolic profiling by mixing drug compounds with chemosynthetic livers in a test tube.  Not only does this allow scientists to see how well the drug is broken down, but the synthetic livers also act as a catalyst, speeding up the typically very slow decomposition process. Therefore scientists can see results  more quickly and on a larger scale than they would with animal studies.

“My testing reproduces the chemical structures of all these metabolites— whatever these animals produce after taking the drug,” Chorghade said.  “Plus, much of this [current] metabolite testing occurs in milligram quantities, but mine occurs in gram quantities.”

Chorghade said this technology comes at just the right time, as more and more legislation is being enacted to ban or limit the use of animal testing.  In 2010, the European Union enacted new regulations known as REACH, which imposed a ban of all animal testing for cosmetic products and aims to drastically lower the amount of animal testing used in pharmaceutical research in the future.

The chemosynthetic livers have not yet been approved by the U.S. Food and Drug Administration, but Chorghade said they have tested their system on more than 50 drugs, and it has accurately mimicked how they were processed in the human body.  While chemosynthetic livers have the potential to greatly reduce the amount of animals needed for drug research, Chorghade said it is unlikely their solution will completely eliminate animal testing altogether.

“The data you get from animals is not 100 percent applicable to human beings, but one has to keep an important thing in mind— that animals are needed to understand mechanisms of disease,” Chorghade said.  “But any contribution we can make to minimizing animal testing -- that is always something be lauded.”