This is a prospective, multicenter, open-label, repeat-dose study conducted in two groups. Subjects in Group 1 and Group 2 will receive treatment for 10 to 14 days (per investigator clinical judgment); dose level (3.0 mg/kg or 4.5 mg/kg) will be determined by the subject's weight at baseline. Study procedures in both groups will be similar except that serial blood samples for assessment of pharmacokinetics will be collected in Group 1. Subjects may only participate in one group of the study.
At least 24 subjects, with at least 8 in each of three age ranges, will be enrolled in Group 1 (PK + safety). At least 36 subjects will be enrolled in Group 2 (safety), with at least 12 in each of the three age ranges.
