AMO Pharma has secured regulatory alignment with the FDA, UK MHRA, and Health Canada on the design of a registrational study for AMO-02 (oral tideglusib), an investigational treatment for congenital myotonic dystrophy type 1 (cDM1) — a rare, inherited neuromuscular disorder affecting muscle function, cognition, development, and cardiac health. The agreed-upon primary endpoint is hospitalization, supported by multiple functional assessments as secondary measures. An update on study initiation is expected in Q3 2026.

The hospitalization endpoint is grounded in data from REACHCDM-X, the longest-running interventional study in cDM1, which logged a hospitalization rate of just 0.14 events per patient per year across 151+ patient-years of exposure, with no deaths or cardiovascular events. These findings helped inform the endpoint choice after the earlier REACH-CDM trial missed its clinician-rated primary endpoint — though it did show significant benefits in cognition, muscle biomarkers, and a composite functional score.

Key Takeaways:

• AMO-02 works by inhibiting GSK3β and disrupting toxic RNA repeat accumulation that drives cDM1 pathology
• In REACHCDM-X, only 1 of 14 discontinuations was due to an adverse event (elevated liver enzymes)
• 98% of REACH-CDM participants opted into the open-label extension after the trial

Why it matters: Congenital DM1 has no approved treatments, and regulatory agreement on a meaningful, disease-relevant endpoint like hospitalization is a critical step toward a potential therapy for this underserved patient population.