After a study phase is complete, the data is collected to determine the drug's effectiveness, if it is safe and if there are any side effects. Depending on the results, researchers then determine whether to stop testing or move to the next phase of study. After phase III of a study is complete, researchers decide if the results are medically important and may submit them to journals for peer-review. Data then may be submitted to the Food and Drug Administration (FDA) for approval.
If a drug is approved, pharmaceutical companies may continue to conduct studies that compare the new drug—in terms of its safety, effectiveness, and cost—to other drugs already on the market or assess a drug's long-term effectiveness and its impact on the quality of a person's life.