Which stage follows the Investigational New Drug (IND) application in the new drug application process?

The correct answer is the Phase I clinical trial, which directly follows the Investigational New Drug (IND) application in the new drug application process. Once a sponsor submits an IND, they must wait for the FDA's approval before proceeding to clinical trials. The Phase I clinical trial is the first phase of human testing and typically involves a small group of healthy volunteers. Its purpose is to assess the safety, tolerability, pharmacokinetics, and pharmacodynamics of the drug.

This stage is crucial as it provides essential information about how the drug behaves in the human body. The primary focus during Phase I is to determine the appropriate dosage and identify any potential side effects. Successful completion of this phase is required before moving on to Phase II trials, where the drug's efficacy is evaluated in a larger group of people who have the condition the drug aims to treat.

In contrast, the FDA approval process occurs after the completion of Phase III clinical trials and is responsible for reviewing the drug's clinical trial data to determine if it is safe and effective for public use. Market launch occurs after FDA approval, making it the final step in bringing a new drug to consumers. Phase IV clinical trials, also referred to as post-marketing studies, take place after the drug has