How much do you know about the types of studies that researchers need to conduct before a new therapy can be approved for use in humans?
Many are familiar with clinical trials, since they involve human volunteers. But before clinical trials can take place, each experimental treatment needs to first undergo an earlier stage of testing, which is mandated by government regulations and done to ensure that clinical research can be done safely. Today, as part of our Drug Development 101 series, we are shedding some light on this part of the R&D process – preclinical research.
The Types of Preclinical Trials
There are two types of trials that researchers conduct – in vitro and in vivo. As the FDA explains, an in vitro test is done in a glass or plastic vessel in the lab, whereas an in vivo test is done in the body of a living organism. This probably makes sense to any Latin speakers – “vitro” means “glass” in Latin, while “vivo” means “life.”
So what do these tests explore? They are used to assess a variety of drug attributes. For example, pharmacokinetic tests investigate how a drug is absorbed, metabolized, and excreted from the body. Meanwhile, genotoxicity tests help detect compounds that could cause damage to human DNA (e.g., gene mutations). Overall, the FDA says they typically expect drug sponsors to accomplish the following in the preclinical stage:
1. Develop a pharmacological profile of the drug (an overview of how it works to produce desired effects)
2. Determine the acute toxicity of the drug in at least two species (identifying any adverse effects of the drug that occur within a short period of time – usually less than 24 hours).
3. Conduct short-term toxicity studies in two species (identifying any adverse effects that occur over a longer period of time – typically ranging from 2 weeks to 3 months)
The Rationale Behind the Research
Why spend all of this time in the lab, instead of just jumping ahead to clinical trials?
Preclinical research is a vital step in the drug development process, enabling researchers to obtain foundational data about an investigational therapy. This information helps them decide whether or not it is safe to be tested in humans, helping to protect patient health, and likely to produce the desired medical effect.
If all goes well, the drug will move on to Phase I clinical trials – something that we will discuss further in the next edition of our Drug Development 101 series. We hope you stay tuned!