Safety, Tolerability, PK, PD and Preliminary Efficacy of ONO-4685

-Part A: Single ascending doses of ONO-4685 as a single IV dose (Cohort A1-A5).

-Part A: Single ascending doses of placebo as a single IV dose (Cohort A1-A5).

-Part B: Multiple doses of ONO-4685 as IV doses over a 4-week treatment period (Cohort B1 and B2)

-Part B: Multiple doses of placebo as IV doses over a 4-week treatment period (Cohort B1 and B2).

-Part C: Multiple doses of ONO-4685 as IV doses over a 4-week treatment period (Cohort C1 and C2).

-Part C: Multiple doses of placebo as IV doses over a 4-week treatment period (Cohort C1 and C2).