00506nas a2200133   4500000000100000000000100001000000100002008004100003260001500044100003600059245002800095856010700123520014200230       2024                            d  c2024-03-251 aU.S. Food & Drug Administration00aAnimal Rule Information  uhttps://www.fda.gov/emergency-preparedness-and-response/mcm-regulatory-science/animal-rule-information3 aThe Animal Rule may be used to grant marketing approval of certain products when human challenge studies would not be ethical or feasible