Footnotes

• Contributors FDA and SAT were involved in the conception and design of the article, drafting, revision and final approval of the manuscript for publication. WJB and DTC were involved in the conception and revision of the manuscript.

• Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors. DTC and SAT are supported by the National Institute for Health Research University College London Hospitals Biomedical Research Centre.

• Competing interests WJB reports personal fees from Roche and personal fees from Merck Serono, outside the submitted work. DTC has received, within the last 2 years, honoraria (paid to his employer) from Excemed for faculty-led education work, and meeting expenses from Novartis and Société des Neurosciences, outside the submitted work. SAT reports a personal fee from Roche, a personal fee and non-financial support from Novartis, a personal fee from Merck Serono, personal fees and non-financial support from Teva, and non-financial support from Biogen, all outside the submitted work.

• Patient consent Obtained.

• Provenance and peer review Commissioned; externally peer reviewed by Alasdair Coles, Cambridge, UK.