Which stage involves testing in humans in Phases I–III?

• A. Clinical trials (I–III)
• B. Preclinical testing
• C. Target identification
• D. Post-market surveillance

Answer: (A)

Testing in humans across Phases I–III takes place during clinical trials. This stage is designed to evaluate safety, dosing, and efficacy in people before a drug is approved. Phase I studies involve a small number of healthy volunteers or patients to assess safety and how the drug is processed in the body. Phase II expands to more patients to gauge efficacy and determine the best dose while continuing to monitor safety. Phase III tests the drug in large patient populations to confirm effectiveness and collect more information on adverse effects, providing the data needed for regulatory approval.

Preclinical testing happens before humans, using lab studies and animal models to assess safety and pharmacology. Target identification is an early discovery step aimed at finding a biological target for a potential therapy. Post-market surveillance (Phase IV) occurs after approval to monitor long-term safety and real-world effectiveness in the general population.