Association of Clinical Research Professionals (ACRP) Certified Professional Practice Exam

A study which seeks to determine the ideal dose and regimen of a new investigational product (IP) to treat hypothyroidism is considered to be in which phase?

1. Phase I

2. Phase II

3. Phase III

4. Phase IV

The correct answer is: Phase II

The study aimed at determining the ideal dose and regimen of a new investigational product (IP) for treating hypothyroidism is categorized as Phase II research. This phase primarily focuses on evaluating the efficacy of the investigational product as well as identifying the optimal dosing regimen and safety profile in a larger population of patients who have the condition being treated. Phase II trials follow Phase I, which mainly involves assessing the safety, tolerability, and pharmacokinetics of a drug in a small group of healthy volunteers. In Phase II, the focus shifts to therapeutic effectiveness alongside continued safety monitoring, thereby allowing researchers to refine dosage and administration schedules based on the observed responses from participants. Subsequent phases, like Phase III, typically involve larger groups and aim to compare the new treatment against standard treatments or placebo, while Phase IV pertains to post-marketing studies that assess long-term effects and further investigate effectiveness in broader populations after the product is already approved. Thus, the correct designation of the study is indeed Phase II.