All drug firms with UK-registered marketing authorisations will need to transfer them, along with batch release and pharmacovigilance activities, to an operation established in the EU or EEA after the UK withdraws from the European Union on March 29, 2019​

https://www.in-pharmatechnologist.com/Article/2018/01/15/Brexit-bad-for-orphans-Concerns-about-cost-to-rare-disease-focused-UK-pharma?utm_source=newsletter_daily&utm_medium=email&utm_campaign=30-Jan-2018&c=B5LaTvdHM6A%2Fi%2BOUlWZYoJF9%2BvbH8Zg9&p2=