RAG-18 shows early target engagement in a three-person DMD cohort

At the World Muscle Society 2026 congress on October 3, Ractigen Therapeutics reported first-in-human results for RAG-18, an investigational RNA-activation treatment for Duchenne muscular dystrophy (DMD).

In the first cohort, three boys received 15 mg by monthly intravenous infusion. Paired muscle biopsies showed a 3.5- to 5.3-fold rise in utrophin signal at the muscle-cell membrane by Day 113—evidence that the treatment reached its intended target in human muscle.

The company reported no dose-limiting toxicities, serious adverse events, or Grade 3-or-higher treatment-emergent events through the reported follow-up; reported adverse events were mild and transient.

Other findings included reduced muscle MRI T2 values in the group and some encouraging motor and pulmonary measurements. However, the functional observations are exploratory and varied between participants; one secondary report notes that all three participants’ North Star Ambulatory Assessment scores fell by three points.

The trial is small and ongoing, so these early findings do not establish clinical benefit. Ractigen said the 30-mg second cohort was fully enrolled and under safety follow-up.