The U.S. Food and Drug Administration (FDA) granted Fast Track designation to ABO-101, a gene therapy for Sanfilippo syndrome type B (MPS IIIB). ABO-101 is designed to deliver a functional copy of the NAGLU gene to the central nervous system and peripheral tissues. The clinical trial is enrolling eligible patients with MPS IIIB at sites in the U.S. and Spain and expects to activate additional sites globally this year to accelerate enrollment. Information about the study is available at and (NCT03315182).

“Receiving Fast Track designation is recognition by FDA that ABO-101 shows promise in treating a serious life-threatening disease and may address the significant unmet medical need of children with MPS IIIB,” said João Siffert, M.D., Chief Executive Officer. “We will continue to interact with global regulatory authorities about the ABO-101 clinical program to facilitate development of this one-time AAV9 mediated gene therapy.”

Fast Track designation is granted by the FDA to facilitate the development and expedite review of investigational therapies intended to treat serious or life-threatening diseases that show potential for addressing significant unmet medical needs. Clinical development of drug products receiving the designation benefit from frequent FDA interactions during all aspects of development and if specific criteria are met, they are eligible for priority review and accelerated approval. ABO-101 has also received Orphan Drug designations in the U.S. and EU, and Rare Pediatric Disease designation from the FDA.

ABO-101 is part of the Company’s portfolio of novel, one-time, AAV9-based gene therapies for rare lysosomal storage diseases. Pre-clinical data demonstrated that ABO-101 delivers a functional copy of the NAGLU gene to the central nervous system and peripheral tissues through a single intravenous infusion. The therapy is designed to address the underlying lysosomal enzyme deficiency responsible for abnormal accumulation of glycosaminoglycans in the brain and throughout the body that result in progressive cell damage and neurodevelopmental and physical decline.