Funding for this research was provided by:
National Institute for Health Research
Received: 12 February 2019
Accepted: 15 May 2019
First Online: 10 June 2019
Change Date: 16 July 2019
Change Type: Correction
Change Details: An amendment to this paper has been published and can be accessed via a link at the top of the paper.
: O.C. and F.B. are consultants for Biogen which manufactures the drug taken by the patients included into the study. However, Biogen did not sponsor the study and patients were seen as per routine clinical care. The remaining authors declare no competing interests.