Regenxbio’s RGX-202 delivered positive pivotal Phase 3 data in Duchenne muscular dystrophy, but investors punished the stock after the company disclosed the FDA recommended a randomized controlled trial during agency discussions. The required RCT would cloud timing for market entry and potential acceleration, especially as investors compare RGX-202’s competitive posture to Sarepta Therapeutics and Solid Biosciences’ ongoing programs.