The FDA granted accelerated approval to Immedica Pharma’s Loargys (pegzilarginase) for arginase 1 deficiency (ARG1‑D), reversing a 2023 refusal-to-file and clearing an enzyme replacement therapy for an ultra‑rare metabolic disorder affecting ~250 U.S. patients. The accelerated approval follows renewed regulatory engagement and additional data submissions. Immedica acquired the asset via previous business moves and positioned pegzilarginase as a replacement therapy to address hyperargininemia-associated neurologic decline. The decision demonstrates how iterative regulatory exchanges and supplemental evidence can flip prior rejections into approvals for ultra-rare indications, enabling patient access where randomized trials are often infeasible.