Regulators Align on AMO Pharma Pivotal cDM1 Study

Rare Daily Staff

AMO Pharma said regulators in the United States, United Kingdom, and Canada have agreed on the design of a planned registrational study for AMO-02 in congenital myotonic dystrophy type 1, with hospitalization as the primary endpoint and functional measures as secondary outcomes.

AMO Pharma said hospitalization was selected because it reflects a major burden for people living with cDM1 and their caregivers. The study is also expected to include multiple functional assessments to capture how the disease affects patients in different ways. The company said the advice followed meetings over the past six months with the FDA, the MHRA, and Health Canada.

The decision appears to align the trial with what matters most to patients and families, rather than with lab or motor scores alone. AMO-02 previously produced mixed results. Although an earlier study showed signals in cognition, biomarkers, and some functional measures, it did not meet its original primary endpoint. By shifting emphasis toward hospitalization and broader functional outcomes, AMO may be able to make a stronger case for the drug based on real-world clinical benefit.

Earlier trials suggested that AMO-02 was generally well tolerated and showed signals of benefit on some functional and cognitive measures. The company is also exploring AMO-02 in other rare disease settings, including arrhythmogenic right ventricular cardiomyopathy.

The company said it plans to survey the cDM1 community to better understand symptoms and the burden of hospitalization.

Congenital myotonic dystrophy type 1, or cDM1, is a rare inherited neuromuscular disorder that can affect muscle function, learning, development, heart health, and overall well-being. AMO Pharma said many patients face serious complications that can require hospitalization and ongoing multidisciplinary care.

AMO-02 is an experimental therapy designed to inhibit GSK3β, an enzyme that appears overactive in cDM1 by contributing to the toxic RNA process that drives the disorder. AMO Pharma says the goal is to improve symptoms and reduce disease burden in patients who often face muscle weakness, developmental issues, and other serious complications.