Multi-Center Study of ManNAc for GNE Myopathy

This is a randomized, placebo-controlled, double-blind, multi-center study to evaluate the long-term safety and clinical efficacy of ManNAc in subjects with GNE myopathy. A total of 51 eligible subjects will be randomized in a 2:1 ratio to receive either ManNAc at 4 g three times daily (total of 12 g/day) or placebo. Subjects will have follow-up visits every 6 months (±7 days) and take study drug for a minimum of 24 months, until their final study visit . The final on-site study visit for a subject is the last expected 6-month follow-up visit that occurs prior to the time the last randomized subject is expected to reach 24 months (extended follow-up). Subjects will undergo screening and baseline evaluations that include clinical laboratory tests, Quantitative Muscle Assessment (QMA), the Inclusion Body Functional Myositis Rating Scale (IBMFRS), and other patient-reported outcomes (PROs), and rehabilitation medicine functional assessments. Follow-up evaluations will occur every six months following baseline, until 24 months after randomization of the last subject. Phone follow-up will occur every month without a clinic visit for the duration of the trial, and the last visit for each subject will be followed by phone follow-up 1 month after the final study visit.