Regenxbio said the FDA has reversed course on key requirements for its Hunter syndrome gene therapy (RGX-121, Navsunli) after a prior rejection. The company plans to resubmit in the third quarter without enrolling additional patients or conducting new studies, according to Regenxbio’s statement. Regenxbio said the FDA acknowledged that existing clinical data are sufficient for consideration of the accelerated approval pathway, and that an untreated control arm is no longer required. The news follows repeated FDA shifts after leadership changes, with the company describing “collaborative discussion” steps that informed the updated alignment. In February, the FDA had questioned elements of Regenxbio’s registrational approach, including “natural history” external control comparability and concerns about surrogate endpoints. Regenxbio’s resubmission now follows an expected Type A meeting to review longer-term biomarker and clinical data. If accepted, Regenxbio’s next steps would keep a pathway open for a neurologic form of mucopolysaccharidosis type II where enzyme replacement is limited by brain penetration.