How many subjects are typically involved in Phase II clinical trials?

Phase II clinical trials are designed primarily to assess the effectiveness of a new drug or treatment in patients who have the condition the drug is intended to treat. Typically, these trials involve a larger number of subjects than Phase I trials, which focus mainly on safety and dosage with a much smaller group.

The inclusion of 100-300 subjects in Phase II trials allows for a more robust evaluation of the treatment's efficacy while still being manageable in terms of resources and time. This scale helps researchers gather significant data on how well the treatment works, its side effects, and optimal dosing strategies, which are essential for the design of Phase III trials.

In contrast, lesser numbers like 10-50 subjects would likely not provide enough information for meaningful statistical analysis regarding efficacy, while numbers like 500-1000 or over 1000 subjects are more characteristic of Phase III trials, which require extensive data across diverse populations to confirm effectiveness and monitor adverse reactions before a treatment can be approved for widespread use. Thus, the range of 100-300 subjects is standard for Phase II, positioning option B as the most accurate choice.