Preclinical testing—Understanding the basics first

Abstract Preclinical testing is the link between drug discovery and availability to the patient. It takes at least 12–15 years for a drug to get from the lab to clinical use. Chemical agents are synthesized or obtained by other high-throughput methods. These compounds are then tested for their effectiveness on the biological target. Various parameters such as maximum dose are evaluated in Phase I. In Phase II, the therapeutic efficacy is evaluated in several hundred patients. Phase III studies are performed on an average of 100–500 patients to confirm therapeutic benefits and safety of the IND. Phase IV uses a broad cohort (10,000 patients) focusing on safety, efficacy, and uses in other indications. Pharmacokinetic and biodistribution studies determine how the body handles a drug. The safety of a drug is established in toxicology studies, which are also used to establish biomarkers for monitoring.