Research shows only 1 in 20 therapies tested on animals make it to human trials. 

An analysis of reviews of translational biomedical research reveals that just 5 per cent of therapies tested in animals reach regulatory approval for human use. 

The study published in PLOS Biology summarises other systematic reviews and provides high level evidence that while the rate of translation to human studies is 50 per cent, there is steep drop off before final approval. 

The authors argue that improvements in experimental approaches could help increase the chances of translation and final approval.

Animal studies are used in basic research to provide insight into aspects of human diseases. 

They have paved the way for a range of therapeutic innovations, although there are several steps that follow before a treatment can be approved for human use. 

In debates about the ethics of animal research, clinical translation is one of the main justifications of such work, yet there is little evidence on how many studies make it through each step and are finally approved.

Benjamin Ineichen of the University of Zurich, Switzerland, and colleagues meta-analysed 122 systematic reviews that evaluated the translation of therapies from animals to humans. 

They assessed how many advanced to a human study, to a randomised controlled trial and to regulatory approval as well as looking at consistency between animal and human study results. 

They found that of 367 therapeutic interventions tested in 54 human diseases, 50 per cent progressed from human to animal studies, 40 per cent to randomised controlled trials and only 5 per cent to regulatory approval. 

They observed a high rate - 86 per cent - of alignment between animal and human studies, and the average time periods for reaching the different stages were five years to any human study, seven years to randomised controlled trials and 10 years to regulatory approval.

Although the number of studies crossing the first stage is higher than previous evidence has suggested, the low rate of final approval suggests there could be deficiencies to address in the design of both animal and early clinical studies.