clinical trials

We often see headlines claiming that new research has found a ‘cure’ for diseases. However, what are the real chances of this being true? How does the current stage of the research affect its ultimate outcome? Has it already been tested on humans, or only on laboratory animals? In this article, we explain why animals are used in biomedicine, the reasons why mice are the most commonly used, the steps and timeframes involved from when a treatment appears effective until it can be determined whether it works in people, the characteristics and limitations of various disease models, and how results should be communicated to inform the public without raising false hopes.

A team from the United States analyzed 611 samples from 341 model mouse strains stored at the Mutant Mouse Resource and Research Centers (MMRRC), a research resource network supported by the National Institutes of Health (NIH). By comparing the identity of each strain with its actual genetic profile, they found that approximately half of the samples showed discrepancies. Although the expected engineered mutation was generally present and many inconsistencies were relatively minor, some had the potential to compromise the validity and reproducibility of the experiments by introducing hidden genetic variables that could alter biological outcomes. The findings are published in Science.

Five out of ten potential treatments move from animal studies to human studies; four to randomised controlled clinical trials; and one in 20 moves on to approval by regulatory agencies, an analysis estimates. Concordance between positive results in animals and in clinical studies is 86%, according to the study, published in PLoS Biology, which pools the findings of 122 published studies on 54 different human diseases.