AVR-RD-05

**AVR-RD-05** is an investigational **gene therapy** developed by AVROBIO for **mucopolysaccharidosis type II (MPS II)**, also known as **Hunter syndrome**, a rare lysosomal storage disorder primarily affecting young boys caused by deficiency in the **iduronate-2-sulfatase (IDS)** enzyme. It uses **ex vivo** lentiviral transduction of a patient's own **hematopoietic stem cells (HSCs)** with a vector encoding the human IDS enzyme coupled to a proprietary protein tag to enhance enzyme stability, tissue uptake, and correction of both peripheral and central nervous system pathology. The therapy has received **FDA orphan drug designation** and **rare pediatric disease designation**, with preclinical data supporting its potential to address limitations of standard enzyme replacement therapy (ERT), which does not halt disease progression or CNS issues.[1][4][7]

Other names

IDS.ApoEII lentiviral vectorautologous CD34 positive hematopoietic stem cell gene therapy encoding IDS ApoEII