Phase II trial
If a pharmaceutical compound clears the phase I trial, investigators move on to phase II trials. At this stage, a few hundred patients are enrolled, and the researchers begin to look at safety as well as efficacy against a specific condition.
Phase II trials can take a year or two. Since phase II is measuring a potential drug against a specific condition, it's not unusual to see the same drug in multiple phase II studies, each looking at different endpoints. In the case of a cancer drug, for example, several trials may be ongoing on at the same time, testing it against different types of cancer.