Famciclovir in Multiple Sclerosis

This is a proof-of-concept study in 30 patients with established Relapsing Remitting Multiple Sclerosis (RRMS). IMP is Famciclovir. It is a phase II type A open label study. Each individuals participation in the study will last 36 weeks and will be divided into three phases: pre-treatment (12 weeks), treatment with famciclovir (12 weeks), and post-treatment (12 weeks). During the first 12 week phase patients will remain on their usual treatment alone; this will be followed by three months of co-treatment with famciclovir and then followed by a final three months post-famciclovir treatment where participants will continue to take their usual treatment for RRMS. The primary aim is to explore the effect of famciclovir (500mg BD) on Epstein-Barr virus (EBV) shedding in the saliva of patients with MS