Of mice and humans

In a Hyderabad lab, scientists at start-up Oncoseek Bio screen drugs in tiny, three-dimensional (3D) balls made up of cells of specific human organs. The spheroids are grown in a well using cell culture. By adding what's known as "insults" — disease-causing toxins, for instance — to the spheroids, Oncoseek creates a "disease in a dish", such as cirrhosis in a liver spheroid, as an alternative to animals to screen compounds during drug discovery.

Oncoseek is not the only start-up working on alternatives to animal models. India has seen an "exponential growth" in labs and companies in this sector over the past four years, says Surat Parvatam, Chief Manager, Centre for Predictive Human Model Systems (CPHMS). The CPHMS is a Hyderabad-based think tank that influences policy on and funding of non-animal models in life sciences.

In the past two decades or so, researchers in the developed world have created alternatives that Surat calls more "relevant for human biology" by using technologies such as microfluidics, advanced computing and 3D bioprinting. Scientists now know that "small, subtle differences in genetics" — between lab animals and humans — can contribute to "a huge difference" in their response to drugs, Surat says. Many diseases also develop differently in animals and humans. These differences have impacted the success of new drug pipelines.

The rate of failure in human clinical trials of drugs that proved safe and effective in animals has hovered at around 90% for 20 years. It is estimated that the cost of bringing a drug successfully to the market — taking failures into account — is nearly a billion dollars on an average. Worse, some very effective drugs that proved safe in animals have shown toxic, even fatal, effects on patients. Conversely, some drugs that proved toxic in animal species have passed tests on in vitro human cells.