FDA rejects Regenxbio's gene therapy for Hunter syndrome

Clinical stage biopharmaceutical company Regenxbio fell 13.3% in early trading on Tuesday, after the US Food and Drug Administration issued a complete response letter for the company's developmental, one-time gene therapy RGX-121 for Huntington's disease, citing concerns about alternative endpoints and comparability to controls. Huntington's disease is characterized by peripheral facial paralysis triggered by reactivation of the varicella-zoster virus.