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MPS II Active Clinical Trials

This page lists active clinical trials for MPS II. This page serves as informative only, Project Alive does not endorse any particular clinical trial. To find additional information, visit and search "mucopolysaccharidosis II" and look for trials that are recruiting. Once you click into a study, you will find the clinical trial site information near the bottom with contact information. Reach out to the listed contact to discuss the details of the trial.


The COMPASS clinical study is looking at the safety and efficacy of an investigational enzyme replacement therapy (ERT) called
DNL310. Unlike current ERT, DNL310 is designed to reach the brain. By delivering medicine across the blood-brain barrier, we want to understand if DNL310 could have an impact on the neurocognitive components of Hunter syndrome (MPS II), like developmental delays, disruptive behaviors, and impaired cognition, in addition to the physical symptoms when compared to existing ERT.
Think your family might be interested?
Visit (NCT05371613) to learn more.
DNL310 is an investigational drug and is
not approved by any Health Authority.



The STARLIGHT Study is a Phase 3 clinical research study evaluating an investigational drug to see if it is
safe and whether it may improve behavioral and cognitive function in individuals with Hunter syndrome.
The study will compare the effects of the investigational drug to the current standard-of-care treatment.
The investigational drug was approved in Japan in 2021 for the treatment of Hunter syndrome.
Approximately 80 study participants will be enrolled and assigned to 1 of 2 groups—Group A or Group B.
Participants in Group A will be at least 2.5 years old but younger than 6 years old, and they will be enrolled
in the study for a 24-month period. Group B is enrolling participants who are at least 6 years old, and they
will be enrolled in the study for a 12-month period. Qualified participants will receive study-related care
and the investigational drug at no cost. Reimbursement for travel and certain study-related expenses will
be available.
Those who qualify and meet all eligibility criteria will receive either the investigational drug or the
standard-of-care treatment, which is enzyme replacement therapy (known commercially as Elaprase®),
through weekly IV infusions (through a vein). Participants will also undergo a variety of tests and
procedures during the study, such as blood and image tests, cognitive testing, and lumbar punctures.
We know the life-changing effects of this disease and the burden it imposes on families. Hope lies in
finding new effective treatments. Please consider participating. For more information and to see if
someone you love qualifies for the STARLIGHT Study, please visit or


RGX-121 is an investigational one-time AAV gene therapy being developed for the treatment of Mucopolysaccharidosis Type II (MPS II). RGX-121 is designed to use the NAV AAV9 vector to deliver the human iduronate-2-sulfatase(IDS) gene to the central nervous system. To participate in this study, candidates must meet any of the following criteria:
o Has a documented diagnosis of MPS II and a has a neurocognitive testing score ≤ 77 (Bayley or Kaufman), OR
o Has a documented diagnosis of MPS II AND has a decline of ≥ 1 standard deviation on serial neurocognitive testing administered between 3 to 36 months apart (Bayley or Kaufman) OR
o Has a relative clinically diagnosed with severe MPS II who has the same IDS mutation as the subject AND in the opinion of a geneticist has inherited a severe form of MPS II OR
o Has documented mutation (s) in IDS that in the opinion of a geneticist is always known to result in a neuronopathic phenotype AND in the opinion of a clinician ID: NCT03566043

UCSF In Utero Enzyme Replacement Therapy Study

For couples at risk or who receive a prenatal diagnosis of Hunter syndrome (MPS II), a clinical trial through the University of California, San Francisco, is available to administer intrauterine enzyme replacement therapy. This study also includes fetuses diagnosed with Mucopolysaccharidoses (MPS) 1 (Hurler), 4a (Morquio type A), 6 (Maroteaux-Lamy), 7 (Sly), Infantile-onset Pompe disease (IOPD), Neuronopathic Gaucher disease (types 2 and 3), and Wolman disease. Please click here for additional information or watch this short video

Watch this short video about a remarkable family that decided to participate in a clinical trial at UC San Francisco after receiving a prenatal diagnosis of Hunter syndrome. If you are an expectant parent or planning to grow your family and are interested in learning more about the trial, please contact the study team at #1-800-RX-FETUS or Identifier: NCT04532047