(Not 100% sure about this being the right place to ask)
According to here, orphan drugs have a market exclusivity of 10 years in Europe.
UK is now (...sooner or later) getting out of Europe, so will this affect the market exclusivity of orphan drugs?
The whole point of orphan drugs was that the diseases they treat are so rare that it's not commercially worth it to produce the drugs, so they get exclusivity to compensate for it.
(Yes, companies have also been abusing this for quite some time, but that's another discussion)
I'm probably a bit naive here, but what I see is the chance that someone in the UK might start producing and selling high-cost drugs for a fraction of the price and make them available for export, especially in the (relatively) not-so-far Europe.
I've seen this, but my question is different: it's not really about trade, it's about regulations.
(Maybe worth nothing: the European Medicines Agency's offices are located in the UK)