Phase 2 of Clinical Trial for New Drug Approval

• A. Up to several hundred
• B. 20-100 healthy volunteers
• C. Only healthy volunteers
• D. Only patients with late-stage disease

Answer: (A)

Phase II tests whether the drug has real effects in people who have the disease and helps pin down the right dosing, while continuing to monitor safety. To detect a meaningful treatment effect, you need a larger group than Phase I, but not as large as Phase III. That’s why the typical size is in the hundreds—up to several hundred participants.

The other descriptions aren’t as accurate for Phase II: this phase isn’t limited to healthy volunteers (that’s more Phase I), and the number of healthy volunteers described is smaller than typical Phase II enrollment. It’s also not restricted to only late-stage patients; Phase II usually involves patients with the disease in various stages to assess efficacy and safety.