Phase 1 of Clinical Trial typically enrolls which participants?

• A. Only elderly participants
• B. 20-100 healthy volunteers or people with the disease/condition
• C. Up to several hundred people with the disease/condition
• D. Only pediatric participants

Answer: (B)

Phase 1 trials focus on safety and how the drug behaves in humans, often starting with dosed, careful exposure in a small group. The typical enrollment is about 20 to 100 participants, and these participants are usually healthy volunteers, though some early studies may enroll patients with the disease or condition if that helps assess safety in the target population. This small, safety-first approach distinguishes Phase 1 from later phases, where the numbers grow to test efficacy and optimal dosing. The other options don’t fit because Phase 1 is not restricted to a single group like elderly or pediatric individuals, and the study size is much smaller than hundreds of participants, which is more characteristic of Phase 2 or 3.