In which phase of the drug approval process is safety and efficacy first evaluated?

The first evaluation of safety and efficacy during the drug approval process occurs in the first phase, known as Phase I. This phase is primarily focused on assessing the safety profile of a new drug. During Phase I trials, the drug is administered to a small group of healthy volunteers or patients to monitor for any adverse effects and to determine how the drug is metabolized and excreted by the body.

While efficacy is not the primary focus of Phase I, initial efficacy data can be gathered, and investigators can start observing how the drug interacts with the body. The main objective is to establish a safe dosage range and identify any side effects.

Subsequent phases, such as Phase II and Phase III, build upon this foundation by further evaluating efficacy and safety in larger populations with the condition the drug intends to treat. Therefore, understanding that safety assessment begins in Phase I is crucial for comprehending the structure of the drug development process.