"Lack of quality?"

Animal-tested therapies barely reach humans

Only five percent of therapies that have been tested on animals are approved for use in humans. This was shown by researchers at the University of Zurich. "However, these could include therapies that are vital for certain people," said study leader Benjamin Ineichen.

For the study, he and his team examined 122 existing research papers on 367 different therapies for human diseases (54 different ones). According to the study, half of the therapies tested on laboratory animals led to clinical work on humans. On average, it took five years before the first large-scale human study was conducted and ten years before regulatory approval was granted.

Great agreement
The team was also able to show that 86 percent of the therapies that were successfully tested on animals were also effective in humans. However, this figure is only based on an estimate. One example is several drugs for multiple sclerosis (MS), an inflammatory disease of the central nervous system. These include fingolimod.

This may sound like very little, but it could include therapies that are vital for certain people.

Studienleiter Benjamin Ineichen, Universität Zürich

However, the substance NXY-059, which should have helped stroke patients, was dropped from the development process. Time and again, therapies based on animal experiments raise high hopes, but ultimately do not achieve the desired effect in humans. After ten years, 95 percent of therapies tested on animals were never approved for use in humans.

False positive results
"It is very likely that a lack of quality in certain animal studies led to false positive results, i.e. that the data suggested a therapeutic effect when in reality there was none," said Ineichen. "As a result, these drugs later fall out of the very rigorous testing in humans." 

The study was published on Thursday in the journal "PLOS Biology".