A First Time in Human Study Exploring Preliminary Safety, Tolerability, Pharmacokinetics and Pharmacodynamics of GSK2618960 in Healthy Volunteers and Patients With Relapsing Remitting Multiple Sclerosis

This is a 3-part study where Parts A, B (single-blind - investigator and subject blind) will enrol healthy volunteers and Part C (open-label) will enrol RRMS patients. Parts A (single ascending dose) and B (repeat ascending dose) will assess safety, tolerability, PK and PD of GSK2618960. Part C (repeat doses) will assess safety, tolerability, PK, PD, immunogenicity, paraclinical (magnetic resonance imaging [MRI] lesion counts) disease activity and markers of Th1 and Th17 mechanisms. Part A: Each of the 24 healthy volunteers (divided in 5 groups), will take part in only 2 of the planned 8 dosing sessions (A-active, P-placebo). Subjects in each group of Part A will be randomized in a 2:1:1 ratio to one of the following sequences: AA, AP or PA such that in each dosing session they will receive study treatment in a 3:1 ratio of active: placebo respectively. Part B: Dosing levels and regimen are dependent upon safety tolerability and PK/receptor occupancy (RO) data from Part A. In Cohort 1, 12 subjects will be randomized in a 3:1 ratio to A or P. Each subject will receive the same study treatment for repeated doses. If the duration of full RO from highest dose in Part A is less than 4 weeks, a second cohort of 12 subjects in Part B may be recruited, based on Dose Escalation Committee (DEC) decision Part C: The 20 RRMS patients will be assigned to active treatments for 2 to 4 repeated doses. Safety/tolerability and PK data monitoring and the decision to proceed to the next dose level of GSK2618960, and the decisions to proceed to Part B and Part C of the study will be made by a dose escalation committee.