Include controlled clinical studies of effectiveness of the drug for a particular indication or indications in patients with the disease or condition under study, and determination of common, short-term side effects and risks associated with the drug. Phase II studies are typically well controlled, closely monitored, and usually involve no more than several hundred patients.
Phase II studies test a treatment with known dose and side effects with a larger number of volunteers to learn more about side effects, how the body responds to the treatment, and whether the treatment is effective in treating the condition.
The second phase of clinical trials. Generally, larger groups of participants are used than that of Phase I trials. Phase II trials further evaluate efficacy and safety.