Data Exclusivity is a little known area of IP law, but one that the EU and Thailand are now negotiating as part of a proposed Thai-EU Free Trade Agreement (FTA). The issue is whether data submitted for marketing approvals to a government's health authority should remain exclusive, that is locked up from others' use. The Thai government proposing a 5 year data exclusivity term. The usual anti big pharma outcry has ensued!
Data exclusivity is controversial. Only a few countries use it, mostly developed markets. It is mentioned in TRIPs article 39.3 (but this is a version watered down from the original clearer draft), that WTO members must protect clinical data. But article 39.3 can be interpreted to prohibit only unauthorized disclosure (arguably different from regulatory approval reliance). Article 39.3 doesn't specify any term either.
Pharma companies of course argue the massive cost of clinical trials should not be forced only on them. They seek to prevent others relying on their trials. But in many countries still they cannot prevent it. An interesting middle way is to compensate them, but this is not really used.