New drugs are frequently tested on animals equivalent to rats and mice before being tested on people. The results of those animal studies are sometimes reported within the media, perhaps creating hope. This “Miraculous”, “promising” or “dramatic” results will at some point be replicated in humans and result in a brand new drug.
But in a broadcast study todaywe discover how few of those treatments tested in animals gain regulatory approval to be used in humans and find yourself in the marketplace.
Swiss and British researchers found that only 5 percent made the grade, and for individuals who did, the method took a median of ten years.
Here's why so few drug candidates in animal trials find yourself as human treatments.
Animal studies have their place, but are flawed.
Animal studies might be invaluable for understanding diseases and finding potential drug targets. But they'll't completely Tell us how secure and effective treatments are for humans.
For example, some possible treatments for Alzheimer's, A stroke And Cancer Worked well in animals but not so well in humans.
So the authors checked out what percentage of treatments successfully transitioned from animal studies to human use, how long it took, and whether results from animal and human studies agreed.
They did this by combining and analyzing the outcomes of studies published before August 2023 using different techniques.
They assessed the standard of included studies using a A meta-analysis (which mixes the outcomes of multiple studies) to see if positive results from animal studies translate into positive results from human studies.
In total, 122 papers were included in a temporary review called “Narrative summary”, with 62 of them included within the meta-analysis.
The researchers then used a statistical technique called “survival analysis” to estimate how long it takes for a treatment to progress from animal studies to clinical trials and regulatory approval.
What they found
In total, the researchers found that 367 therapeutic interventions were tested in 54 human diseases:
- 50% progressed from animal studies to human clinical trials.
- 40% progressed to randomized controlled trials (larger, clinical phase 3 trials, which are frequently required before regulatory approval).
- 5% received regulatory approval.
Their meta-analysis found that 86 percent of positive results from animal studies were later translated into positive ends in human trials.
For animal studies that progress, researchers found that on average:
- Five years for animal studies to achieve any human studies
- Seven years to achieve a randomized controlled trial
- Ten years for regulatory approval.
Why the gap?
The authors found that lots of the animal studies were poorly designed, making their findings less accurate.
For example, most didn't involve blinding, where the investigator doesn't know which animal received each treatment, or randomization of animals to treatment.
Many animal studies also involved too few animals to offer reliable evidence of whether the treatment was successful.
Animal studies often involve young, healthy animals, whereas human patients can have multiple health conditions and be elderly. Animal studies often deal with how a drug works on the molecular level, while human studies deal with the general effectiveness of the drug.
Finally, results measured in animal studies may not all the time reflect crucial clinical results for patients.
Seventy Four/Shutterstock
The authors suggest that researchers have to concentrate to the standard and relevance of animal studies if we would like to enhance drug development.
Researchers have to make sure that studies are well designed, use appropriate animal models, and measure outcomes which can be necessary to patients.
The authors also recommend closer collaboration between animal and human researchers to assist bridge the gap between preclinical and clinical research.
How fearful should we be?
The use of animals in research raises many ethical questions on the suffering and harm caused to them for potentially limited human profit.
The high failure rate of animal studies to translate to human therapy exacerbates these concerns, because it calls into query the justification for using animals in research.
The discrepancy between animal and human results highlights the restrictions of animal models in accurately predicting human responses to drugs. This raises questions on the scientific validity of relying solely on animal data for drug development decisions.
However, on the intense side, the high failure rate and price of animal studies has encouraged the event of other research methods that don't depend on animals.
These include (laboratory) studies, human related cells and tissue. Models, A chip on the organ systems, and computational In silico Modeling including simulation on computers.
Clearly, it could be great if we didn't should use animals in drug development. But with the increasing use of other methods equivalent to computer modeling, and the appearance of Artificial intelligence To design latest drugs and minimize animal testing, it is feasible.