POLICY ON POST-APPROVAL STUDIES 1. Post-approval studies may be required to provide additional information on the efficacy, safety, and use of the drug in populations more diverse than included in the clinical trials conducted prior to approval of the new drug in accordance with the provisions of the rules. 2. Necessary guidance documents should o be developed to provide the extent of requirements of such studies depending on the nature of the new drug, rarity and severity, unmet medical need, etc. for the disease for which the drug is indicated and the overall data that was available at the time of approval.