The switch that turns genes back on: three boys, one monthly drip, a first for medicine

For the first time, doctors have flipped a genetic switch on inside living human muscle. At the World Muscle Society meeting in Hiroshima, Ractigen Therapeutics showed first-in-human data for RAG-18 — a monthly IV drip of small activating RNA that tells the body to make more utrophin, a protein that can stand in for the dystrophin missing in Duchenne muscular dystrophy. In three boys, aged 6.8 to 12.7 and each carrying a different DMD mutation, paired muscle biopsies showed utrophin levels up 3.5 to 5.3 times, less fat creeping into the muscle, and encouraging trends in movement and breathing. No dose-limiting side effects appeared. Because the approach boosts a backup protein rather than fixing a specific mutation, it could in principle help any boy with Duchenne — the disease's cruel lottery of mutations wouldn't matter. The US FDA has already granted it Orphan and Rare Pediatric Disease designations.