The U.S. Food and Drug Administration has lifted the clinical hold on Rocket Pharmaceuticals’ pivotal Phase 2 trial of RP-A501, its investigational gene therapy for Danon disease, clearing the study to resume less than three months after the regulator halted it following a participant’s death. Under the FDA-approved amendments, the single-arm, 12-patient trial will restart with a reduced dose of 3.8×10^13 genome copies per kilogram given sequentially to three patients at least four weeks apart. Rocket will discontinue prophylactic use of complement C3 inhibitors and maintain a pared-back immunomodulatory regimen that includes sirolimus, rituximab and steroids, with eculizumab held in reserve if complement activation emerges. The agency placed the study on hold in May after a patient receiving a higher 6.7×10^13 GC/kg dose and complement blockade died from capillary leak syndrome and infection. In lifting the suspension, regulators said the company had satisfactorily addressed the safety concerns. RP-A501 aims to restore LAMP2B protein expression and reduce left-ventricular mass in Danon disease, a rare genetic disorder that can lead to early-onset heart failure and affects fewer than 1,000 U.S. patients. Rocket’s shares surged more than 20 percent in early trading on the FDA’s decision.