This is a randomized, double-blind, placebo-controlled study in pediatric subjects with CG. Three age groups (≥2 to ≤6-year olds, ≥7 to ≤12-year olds, and ≥13 to <18- year olds) will be enrolled. The study is designed to assess the clinical benefit (changes in how pediatric patients with CG feels and function, changes in ocular disorders, and changes in sexual maturation, growth and development) as well as the safety, PK, and PD (reduction of galactitol levels) of AT-007 in pediatric subjects with CG. The study consists of 2 main parts, Part A and Part B, and an open-label extension (OLE).~Part A is an intra-patient dose escalation evaluating multiple ascending doses (MAD) of AT-007.~Part B is designed to assess the clinical benefits of long-term administration of AT-007 (at the optimum dose identified in Part A) on how patients with CG feel and function.~Open-label extension (OLE) is an active treatment extension for patients who received placebo treatment in Part B.
This study is designed to assess the clinical benefit as well as the safety, pharmacokinetics (PK), and pharmacodynamics (PD) (reduction of galactitol levels) of AT-007 in pediatric subjects with Classic Galactosemia (CG).