Participants with a documented clinical diagnosis of DM1 (CTG expansion of \>150 repeats in DMPK gene measured in peripheral blood mononuclear cells)
Ambulatory, defined as able to complete a 10-meter walk/run test at screening without the use of assistive devices such as canes, walkers, or orthoses, except for ankle-foot orthoses
Presence for \>3 seconds of grip myotonia as confirmed by a central reader
You may not be if
Participants with congenital DM1
Medical Research Council Muscle Scale score of less than 4 on ankle dorsiflexion or significant tibialis anterior atrophy that prevents a muscle biopsy
Use of mexiletine or other agent for myotonia within 21 days or 5 half-lives, whichever is longer, prior to screening
Clareo Health | Study of ATX-01 in Participants With DM1
