This code system http://hl7.org/fhir/medicinal-product-special-measures defines the following codes:

CodeDisplayDefinition
Post-authorisationStudies Requirement to conduct post-authorisation studiesRequirement to conduct post-authorisation studies
<status value="draft"/><experimental value="false"/><date value="2021-01-05T10:01:24+11:00"/><publisher value="HL7 (FHIR Project)"/><contact><telecom><system value="url"/><value value="http://hl7.org/fhir"/></telecom><telecom><system value="email"/><value value="fhir@lists.hl7.org"/></telecom></contact><description value="Extra measures defined for a Medicinal Product, such as requirement to conduct post-authorisation studies."/><caseSensitive value="true"/><valueSet value="http://hl7.org/fhir/ValueSet/medicinal-product-special-measures"/><content value="complete"/><concept><code value="Post-authorisationStudies"/><display value="Requirement to conduct post-authorisation studies"/><definition value="Requirement to conduct post-authorisation studies"/></concept></CodeSystem>