This is a multicenter, multiple ascending dose, open-label study (Core Study) with an Extension Phase. The Core Study consisted of 2 phases, the Pretreatment Phase and the Treatment Phase. The Pretreatment Phase lasted up to 2 weeks in duration, during which participants were assessed for their eligibility to participate in the study. The Treatment Phase consisted of 3 periods: Titration (7 weeks), Maintenance (4 weeks), and Follow-up (4 weeks; only for those participants not rolling over into the Extension Phase after completing the Treatment Phase and for those participants who discontinued from the study). All subjects who completed all scheduled visits up to and including the final visit of the Treatment Phase (Core Study) were eligible to participate in the Extension Phase of the study. The Extension Phase consisted of 2 periods: Maintenance (41 weeks) and Follow-up (4 weeks).