Phase 1 is a randomized, double-blind, placebo-controlled, single-ascending dose (SAD) trial of PRO-1562 in healthy adult participants at a single clinical research unit to characterize the safety and pharmacokinetics of a range of oral doses of PRO-1562. Phase 2a is a randomized, double-blind, placebo-controlled, multi-center, 6-month trial of PRO-1562 in adult patients with relapsing multiple sclerosis who also have chronic optic neuropathy. Patients will remain on their stable regimen of an approved MS disease modifying therapy during the trial. Oral PRO-1562 or placebo will be dosed once a month at scheduled clinic visits. Participants will be given the option to continue on their assigned study treatment after completing the 6-month treatment period until the last patient completes the 6-month treatment period.
