The Regulatory Authority is the drug registration office in the country where a trial is conducted. At present, there is a well established movement to harmonize the different regulatory regimes of Europe, Japan and the United States but clinical trials are sitll under the jurisdiction of individual country laws. This means that approval to conduct trials must be obtained from each country.
Multinational trials involve relations with several authorities but must nevertheless conform to local legislation. For example, Adverse Events occurring during a trial must be reported to each authority.