A Study of Migalastat in Pediatric Subjects (2 to <12 Yrs) With Fabry Disease and Amenable GLA Variants

This is a Phase 3b, 2-stage, open-label, uncontrolled, multicenter study to evaluate the safety, PK, PD, and efficacy of 12 months of migalastat treatment in pediatric subjects 2 to \< 12 years of age with Fabry disease and with amenable GLA variants. Subjects must be either naïve to enzyme replacement therapy (ERT) or have stopped ERT at least 14 days before Baseline visit. The study will consist of 2 treatment stages followed by an open-label extension (OLE). Stage 1 will be a treatment period of approximately 3 months (12 weeks); Stage 2 will be a treatment period of 9 months. There will be no break in treatment between Stages 1 and 2. There will be a 30-day (untreated) safety follow-up period for subjects who discontinue treatment at any time. Subjects will be randomly assigned 1:1:1 to 1 of 3 PK sampling groups using interactive response technology (IRT). Four blood samples for the determination of migalastat concentrations in plasma will be collected in one 24-hour period between Day 15 and Day 30 and at Month 6, and 1 PK (trough) sample will be collected at Month 6 and again at Month 12.