Efficacy and Safety of Tideglusib in Congenital Myotonic Dystrophy

• Change in Clinical Global Impression- Improvement Scale (CGI-I) scores[ Time Frame: 22 weeks ]
  The clinician administered CGI-I rates how much the subject's illness has improved or worsened relative to a baseline state.
• Change in Top 3 Caregiver Concerns Visual Analogue Scale (VAS) score[ Time Frame: 22 Weeks ]
  The Top 3 concerns VAS allows caregivers to identify their main three causes of concern, related to the subject's myotonic dystrophy, rather than these being pre-specified within a scale and then rating how these concerns have changed at specific time-points during the study.
• Caregiver Completed Congenital DM1 Rating Scale (CC-CDM1-RS)[ Time Frame: 22 weeks ]
  The Caregiver-Completed Congenital DM1 Scale is a caregiver assessment of the subject on symptoms that may occur in individuals with CDM1. There are a total of 11 clinically relevant symptoms that the caregiver is asked to rate the severity of.
• Clinical Global Impression - Severity Scale (CGI-S)[ Time Frame: 22 weeks ]
  The Clinical Global Impression - Severity Scale (CGI-S) is a 7-point scale that requires the clinician to rate the severity of the subject's illness at the time of assessment, relative to the clinician's past experience with subjects who have the same diagnosis.
• Incidence of Adverse events (AEs), including serious adverse events (SAEs), between Screening to end of study.[ Time Frame: 22 to 28 weeks ]
  Adverse events may be volunteered spontaneously by the subject, or discovered as a result of general, non-leading questioning by physician.
• Incidence of abnormal findings in objective assessments (e.g. laboratory values, ECGs, vital signs and bone mineral density) between Screening and end of study.[ Time Frame: 22 to 28 weeks ]
  Abnormal laboratory findings (e.g. hematology, liver function, biochemistry, urinalysis) or other abnormal assessments (e.g. ECGs, vital signs) that are judged by the Investigator as clinically significant will be recorded as AEs or SAEs if they meet the definition of an AE. The Investigator will exercise his or her medical and scientific judgment in deciding whether an abnormal laboratory finding or other abnormal assessment is clinically significant.

This is a randomized, multicenter, double-blind, placebo-controlled, Phase 2/3 study of patients (aged 6 to 16 years) diagnosed with Congenital Myotonic Dystrophy (Congenital DM1).

• Drug: Tideglusib
  Tideglusib for oral suspension, weight-adjusted at 400mg, 600mg or 1000 mg dose levels, once daily
• Drug: Placebo
  Matching placebo formulation

• Experimental: Tideglusib
  Weight adjusted tideglusib, orally, once daily
• Placebo Comparator: Placebo
  Matching placebo, orally, once daily