The U.S. Food and Drug Administration (FDA) has granted orphan drug designation for AVROBIO’s AVR-RD-05, a gene therapy for the treatment of mucopolysaccharidosis type II (MPSII), or Hunter syndrome, a rare and seriously debilitating lysosomal disorder that primarily affects young boys.
Orphan drug designation is granted by FDA to drugs and biologics that are intended for the safe and effective treatment, diagnosis or prevention of rare diseases or conditions that affect fewer than 200,000 people in the U.S. Orphan drug designation provides certain incentives, which may include tax credits towards the cost of clinical trials and prescription drug user fee waivers.
Hunter syndrome is caused by a deficiency in the lysosomal enzyme iduronate-2-sulfatase (IDS), which is essential for breaking down large sugar molecules. The gene therapy uses a patient’s own hematopoietic stem cells (HSCs) that are transduced ex vivo with a lentiviral vector encoding the human IDS enzyme.
The company’s planned collaborator-sponsored Phase 1/2 clinical trial for Hunter syndrome is expected to commence in 2023 under the company’s collaboration with the University of Manchester, UK.
The program was developed by Brian Bigger, Ph.D., professor of cell and gene therapy at the University of Manchester, who has previously published preclinical data demonstrating that HSC gene therapy deploying an optimized, proprietary tag has the potential to correct peripheral disease and normalize brain pathology.