Rocket Pharmaceuticals announced that the U.S. Food and Drug Administration (FDA) has lifted the clinical hold on its Phase 2 trial of RP-A501, a one-time AAV9 gene therapy targeting the LAMP2B gene for Danon disease. The hold had been imposed in May 2025 following the death of a patient due to serious complications, including capillary leak syndrome and infection. The FDA approved the trial's resumption after Rocket Pharmaceuticals revised the protocol, including reducing the dose to 3.8x10¹³ GC/kg and modifying the immune modulator regimen. The trial will restart with three patients treated sequentially. Following the announcement, Rocket Pharmaceuticals’ shares surged between 20% and 25% in pre-market trading. The company’s gene therapy study is now cleared to proceed after nearly three months of suspension.