May 05, 2026 —
Sangrail Biologics, a clinical-stage gene therapy company focused on rare pediatric genetic diseases, has officially launched and highlighted its lead clinical program, SNG-101, formerly known as ABO-101. SNG-101 is a potential first-in-class AAV9-based gene therapy designed to treat mucopolysaccharidosis type IIIB, also known as MPS IIIB or Sanfilippo syndrome type B, a devastating lysosomal storage disease that causes progressive neurocognitive decline, speech and mobility loss, and premature death.
MPS IIIB is caused by mutations in the NAGLU gene, which lead to deficient activity of the N-acetyl-α-D-glucosaminidase enzyme. Without sufficient NAGLU activity, toxic levels of heparan sulfate accumulate in the brain and other organs, contributing to progressive neurological and systemic disease. There are currently no approved treatments for MPS IIIB, making the development of disease-modifying therapies especially urgent for affected children and families.
SNG-101 is designed as a one-time intravenous AAV9 gene therapy that delivers a functional copy of the NAGLU gene to cells in the central nervous system and peripheral organs. By restoring enzyme function, the therapy aims to enable the breakdown of accumulated heparan sulfate and address the underlying genetic cause of disease rather than only managing symptoms.
According to Sangrail Biologics, 14 patients with MPS IIIB have received SNG-101 through a global, open-label, dose-escalating Phase 1/2 clinical trial and named-patient programs. Patients were treated at three intravenous dose levels: 2E13 vg/kg, 5E13 vg/kg, or 1E14 vg/kg. In the Phase 1/2 study, biomarker improvements were reported across cerebrospinal fluid, plasma, and urine. NAGLU enzyme activity in cerebrospinal fluid showed a dose-dependent response, normalizing in all subjects by 30 days, while plasma NAGLU activity normalized by 7 days and remained above baseline throughout the study.
The company also reported reductions in several disease-relevant biomarkers, including decreases in CSF GM2 and GM3, which are associated with neuronal loss, as well as reductions in urinary glycosaminoglycans. Liver and spleen volumes, adjusted for weight and height, decreased significantly as early as six months and remained reduced during follow-up. Importantly, investigators also observed improvements or stabilization of neurocognitive function in the youngest treated patients, supporting the potential value of earlier intervention.
SNG-101 has received FDA Fast Track, Orphan Drug, and Rare Pediatric Disease designations, with the Rare Pediatric Disease Designation potentially qualifying the program for a Priority Review Voucher upon BLA approval. The program has also received Orphan Drug Designation from the European Medicines Agency. These regulatory designations reflect the high unmet medical need in MPS IIIB and may support an accelerated development pathway if clinical data continue to demonstrate meaningful benefit.
The launch of Sangrail Biologics highlights continued momentum in systemically delivered AAV gene therapy for pediatric lysosomal storage diseases. For conditions such as MPS IIIB, where both CNS and peripheral tissues are affected, AAV9-based delivery offers a potentially powerful strategy to address multi-organ disease through a single administration. While further clinical development and long-term follow-up will be essential, SNG-101 represents an important program to watch in the rare disease gene therapy landscape.
