That would certainly stir the domestic research/legal establishment. Every manufacturer would develop their new medicines in the EU.
Not that the above projection is all bad. There would be thrashing, but eventually laws on medical development would get more or less harmonized.
“Every manufacturer would develop their new medicines in the EU.”
US drug designers aren’t going to move readily. Learning French or German isn’t easy and it would interfere with drug design work. Housing in England is generally terribly expensive. Scotland gets real cold.
Drug approval testing is often multi-national.