Page last updated: July 23, 2026
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Trial Information
This study is the first in-human clinical trial to explore the safety, tolerability, and clinical efficacy of ex vivo gene therapy OTL-201 (autologous CD34+ cells transduced with a lentiviral vector containing the human SGSH gene) in MPSIIIA patients.
This study aims to recruit 3 to 5 patients with MPS IIIA who satisfy the inclusion and exclusion criteria and provide full consent, between 3 months and 24 months of age. The investigational medicinal product (IMP) will be a cell-based gene therapy that uses genetically modified autologous CD34+ haematopoietic stem cells transduced with a lentiviral vector containing the human SGSH gene. Patients will be followed up for a minimum of 3 years after gene therapy.
Study Details
Study Title: Gene Therapy with Modified Autologous Hematopoietic Stem Cells for Patients with Mucopolysaccharidosis Type IIIA
Trial Listing: Read this clinical trial’s information on ClinicalTrials.gov, which includes enrollment criteria, trial locations, and study contact information.
Study Status: Active, Not Recruiting
Number of participants: 5 (estimated)
Duration: 3 years; Estimated study completion date of October 2026
Location: Manchester University NHS Foundation Trust, Manchester, United Kingdom
Trial Updates
May 2026
Orchard Therapeutics received the MHRA Innovation Passport for OTL-201, its investigational gene therapy for MPS-IIIA (Sanfilippo syndrome type A), in the United Kingdom (UK). The designation, announced April 30, 2026, opens the UK’s Innovative Licensing and Access Pathway (ILAP) for a rare pediatric disease with no approved disease-modifying therapy. Read more.
October 2024
Simon Jones, MBChB, BSc, Medicine, presented on this therapy’s development during the “Updates on Clinical Trials for Sanfilippo Syndrome (Part 2)” session at ADVANCE 2024. Watch Jones’ presentation below.
February 2023
University of Manchester has stated that early results of its OTL-201 gene therapy trial for Sanfilippo Syndrome “show promise.”
This therapy collects a patient’s own blood stem cells, inserts a working copy of the SGSH gene using a modified virus into the cells, and then gives back to the patient their blood stem cells that now have the working copy of the SGSH gene.
The hope is that this method enables patients to “make the missing SGSH enzyme and provide it throughout the body from blood cells made in the bone marrow. These stem cells can make monocytes, which are specialized blood cells able to enter the brain. This means they can release SGSH enzyme to potentially help stop damage to the brain.”
Read the complete statement by University of Manchester regarding the trial’s early results, including improvements seen in cognitive development, tolerance of the therapy, and levels of SGSH enzyme in patients. Read the press release.
December 2022
Orchard Therapeutics announces promising early neurocognitive outcomes from ongoing proof-of-concept study of OTL-201 in MPS-IIIA. Read the press release.
June 2021
Orchard Therapeutics announced that it has fully enrolled 5 patients in its proof of concept study. Read more.
February 2021
Orchard Therapeutics announced “supportive initial OTL-201 biomarker data for mucopolysaccharidosis type IIIA (MPS-IIIA or Sanfilippo syndrome type A) in three patients.” Read more.
April 2020
Orchard Therapeutics announced that the first patient had been dosed with the open-label, proof-of-concept investigational study of OTL-201, an ex vivo autologous hematopoietic stem cell (HSC) gene therapy for the treatment of mucopolysaccharidosis type IIIA (MPS-IIIA).