Mucopolysaccharidosis Type IIIBEAPNCT07733856
Early Access Treatment With Tralesinidase Alfa in Mucopolysaccharidosis Type IIIB (Sanfilippo Syndrome Type B)
A study testing Tralesinidase alfa (TA) in people with Mucopolysaccharidosis Type IIIB and MPS IIIB (Sanfilippo B Syndrome), run by Spruce Biosciences at 1 site in United States.
Trial summary
This is an intermediate-size patient population Early Access Program (EAP) providing access to intracerebroventricular (ICV) tralesinidase alfa (TA) for participants with mucopolysaccharidosis type IIIB (MPS IIIB, Sanfilippo Syndrome Type B). Read more about this study
- Who is it for?
- Ages 12 months and older
- Conditions the study is for
- Mucopolysaccharidosis Type IIIB, MPS IIIB (Sanfilippo B Syndrome)
- What is being tested?
- Tralesinidase alfa (TA)
- Type of treatment
- Injection or infusion
- How many people
- Not given
- Where
- 1 siteUnited States
- Study dates
- Start not givento not given
- Phase
- Expanded access
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 12 months and older
- All sexes
- Child, Adult, Older adult
Who may be able to join
- Has a diagnosis of MPS IIIB confirmed by deficient NAGLU enzyme activity analyzed at the laboratory during Screening.
- Is ≥12 and ≤60 months of age with a BSID-III-C raw score ≥70. or Is >60 months of age regardless of cognitive level. Has provided written informed consent from a parent or legal guardian Has been determined by the investigator, after consultation with the participant (if applicable) and their family/caregiver, that the known risks of TA ICV infusion are outweighed by its potential benefits.
- If female and of childbearing potential, agrees to follow contraception guidelines from screening until 30 days after the last dose of TA.
- Has the ability to comply with program requirements, in the opinion of the investigator.
Who cannot join
- Has contraindications for neurosurgery (e.g., congenital heart disease, severe respiratory impairment, or clotting abnormalities).
- Has contraindications for MRI scans, if the investigator deems an MRI and not a CT scan is required for ICV access device placement or follow-up post-placement.
- Has a history of poorly controlled seizure disorder. Is prone to complications from ICV infusion, including participants with hydrocephalus or ventricular shunts.
- Has received any investigational medication within 30 days prior to the Baseline Visit or is scheduled to receive any investigational drug during the course of the program.
- Has a medical condition or extenuating circumstance that, in the opinion of the investigator, might compromise the participant's ability to comply with program requirements, the participant's well-being or safety, or the interpretability of the participant's clinical data.
Trial locations and contacts
1 site in 1 country.
United States1 site
- Available
Children's Hospital Oakland Research Institution
Oakland, California, 94609
Erin O'Neil, erin.oneil@ucsf.edu
Paul Harmatz, MD
About this study
Official title: Open-Label Early Access Treatment With Intracerebroventricular Tralesinidase Alfa in Mucopolysaccharidosis Type IIIB (MPS IIIB, Sanfilippo Syndrome Type B)
This is an intermediate-size patient population Early Access Program (EAP) providing access to intracerebroventricular (ICV) tralesinidase alfa (TA) for participants with mucopolysaccharidosis type IIIB (MPS IIIB, Sanfilippo Syndrome Type B). The primary objectives are to allow early access to TA treatment and to evaluate the safety and tolerability of TA ICV infusion. Approximately 10 participants will be enrolled at up to 3 US sites and treated with TA once weekly via ICV infusion for up to approximately 52 weeks, or until TA becomes commercially available.
Read the detailed description
MPS IIIB (Sanfilippo Syndrome Type B) is an ultra-rare, autosomal recessive lysosomal storage disease caused by deficiency of alpha-N-acetylglucosaminidase (NAGLU). In the absence of NAGLU activity, heparan sulfate (HS) and its metabolite HS non-reducing end (HS-NRE) accumulate in lysosomes, causing progressive CNS neurodegeneration. Affected children experience developmental delays beginning between ages 1 and 4, followed by cognitive regression and loss of motor function, with death typically occurring in the second decade of life.
Tralesinidase alfa (TA) is a recombinant human NAGLU-IGF2 fusion protein administered directly into the CNS via ICV infusion. In Study 250-201 and its extension studies, weekly ICV TA normalized or near-normalized CSF HS-NRE levels in all participants within 4 weeks, with effects maintained for up to 5 years. TA treatment was associated with long-term stabilization of cortical gray matter volume and prevention of age-dependent cognitive decline.
Study 250-502 is an intermediate-size EAP under 21 CFR 312.315, intended for participants who are older than 5 years of age or have a BSID-III-C raw score ≥70. The program will continue until TA receives US regulatory approval and commercial availability, or until the allocated TA supply is exhausted.
Participants receive TA (200 mg if age 1 to <2 years; 300 mg if age ≥2 years) administered via ICV infusion once weekly after surgical implantation of an ICV access device (reservoir and catheter). The first ICV infusion is administered in an inpatient setting; subsequent infusions are done in an outpatient setting. Participants are pretreated with antihistamine approximately 30 minutes before each infusion.
- Being tested
- Tralesinidase alfa (TA)
- Keywords
- Sanfilippo, MPS IIIB, Enzyme Replacement Therapy, NAGLU, Expanded Access, EAP
- Medical subject headings
- Mucopolysaccharidosis III
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Tralesinidase alfa (TA)Drug
Tralesinidase alfa (TA) is a sterile solution of recombinant human alpha-N-acetylglucosaminidase fused with insulin-like growth factor 2 (rhNAGLU-IGF2), formulated at 30 mg/mL for ICV infusion. Dose: 200 mg (6.7 mL) for participants age ≥12 to <24 months; 300 mg (10 mL) for participants age ≥24 months. Administered once weekly via ICV reservoir following isovolumetric removal of up to 10 mL CSF, infused over approximately 10 minutes. Stored frozen at -40°C (±10°C).
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted29 Jul 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Mucopolysaccharidosis Type IIIBStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Expanded access
Sponsor and investigators
- Lead sponsor
- Spruce Biosciences
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07733856
- Sponsor's protocol ID
- 250-502
- Acronym
- EAP
- Status last verified
- Sep 2026
- First submitted
- 23 Jul 2026
- Last updated
- 6 Oct 2026
- Results posted
- No
Study at a glance
From the registry record, last updated by the sponsor on 6 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Open-Label Early Access Treatment With Intracerebroventricular Tralesinidase Alfa in Mucopolysaccharidosis Type IIIB (MPS IIIB, Sanfilippo Syndrome Type B)
- ClinicalTrials.gov ID
- NCT07733856
- Acronym / sponsor ID
- EAP / 250-502
- Keywords
- Sanfilippo, MPS IIIB, Enzyme Replacement Therapy, NAGLU, Expanded Access, EAP
- Study type
- Expanded access
- Recruitment status
- Available
- Lead sponsor
- Spruce BiosciencesIndustry (pharma, biotech, devices)
- First posted
- 29 Jul 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This is an intermediate-size patient population Early Access Program (EAP) providing access to intracerebroventricular (ICV) tralesinidase alfa (TA) for participants with mucopolysaccharidosis type IIIB (MPS IIIB, Sanfilippo Syndrome Type B). The primary objectives are to allow early access to TA treatment and to evaluate the safety and tolerability of TA ICV infusion. Approximately 10 participants will be enrolled at up to 3 US sites and treated with TA once weekly via ICV infusion for up to approximately 52 weeks, or until TA becomes commercially available.
Detailed description
MPS IIIB (Sanfilippo Syndrome Type B) is an ultra-rare, autosomal recessive lysosomal storage disease caused by deficiency of alpha-N-acetylglucosaminidase (NAGLU). In the absence of NAGLU activity, heparan sulfate (HS) and its metabolite HS non-reducing end (HS-NRE) accumulate in lysosomes, causing progressive CNS neurodegeneration. Affected children experience developmental delays beginning between ages 1 and 4, followed by cognitive regression and loss of motor function, with death typically occurring in the second decade of life.
Tralesinidase alfa (TA) is a recombinant human NAGLU-IGF2 fusion protein administered directly into the CNS via ICV infusion. In Study 250-201 and its extension studies, weekly ICV TA normalized or near-normalized CSF HS-NRE levels in all participants within 4 weeks, with effects maintained for up to 5 years. TA treatment was associated with long-term stabilization of cortical gray matter volume and prevention of age-dependent cognitive decline.
Study 250-502 is an intermediate-size EAP under 21 CFR 312.315, intended for participants who are older than 5 years of age or have a BSID-III-C raw score ≥70. The program will continue until TA receives US regulatory approval and commercial availability, or until the allocated TA supply is exhausted.
Participants receive TA (200 mg if age 1 to <2 years; 300 mg if age ≥2 years) administered via ICV infusion once weekly after surgical implantation of an ICV access device (reservoir and catheter). The first ICV infusion is administered in an inpatient setting; subsequent infusions are done in an outpatient setting. Participants are pretreated with antihistamine approximately 30 minutes before each infusion.
Study design
Who may qualify
- Ages
- 12 months and older
- Sex
- All
- Age groups
- Child, Adult, Older adult
Key inclusion criteria (4 listed)
- Has a diagnosis of MPS IIIB confirmed by deficient NAGLU enzyme activity analyzed at the laboratory during Screening.
- Is ≥12 and ≤60 months of age with a BSID-III-C raw score ≥70. or Is >60 months of age regardless of cognitive level. Has provided written informed consent from a parent or legal guardian Has been determined by the investigator, after consultation with the participant (if applicable) and their family/caregiver, that the known risks of TA ICV infusion are outweighed by its potential benefits.
- If female and of childbearing potential, agrees to follow contraception guidelines from screening until 30 days after the last dose of TA.
- Has the ability to comply with program requirements, in the opinion of the investigator.
Key exclusion criteria (5 listed)
- Has contraindications for neurosurgery (e.g., congenital heart disease, severe respiratory impairment, or clotting abnormalities).
- Has contraindications for MRI scans, if the investigator deems an MRI and not a CT scan is required for ICV access device placement or follow-up post-placement.
- Has a history of poorly controlled seizure disorder. Is prone to complications from ICV infusion, including participants with hydrocephalus or ventricular shunts.
- Has received any investigational medication within 30 days prior to the Baseline Visit or is scheduled to receive any investigational drug during the course of the program.
- Has a medical condition or extenuating circumstance that, in the opinion of the investigator, might compromise the participant's ability to comply with program requirements, the participant's well-being or safety, or the interpretability of the participant's clinical data.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Tralesinidase alfa (TA)Tralesinidase alfa (TA) is a sterile solution of recombinant human alpha-N-acetylglucosaminidase fused with insulin-like growth factor 2 (rhNAGLU-IGF2), formulated at 30 mg/mL for ICV infusion. Dose: 200 mg (6.7 mL) for participants age ≥12 to <24 months; 300 mg (10 mL) for participants age ≥24 months. Administered once weekly via ICV reservoir following isovolumetric removal of up to 10 mL CSF, infused over approximately 10 minutes. Stored frozen at -40°C (±10°C). | Drug | – |
Primary outcome
Not reported in the source record.
Results and safety
Results are not available in the source record.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 6 Oct 2026.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Tralesinidase alfa (TA) in people with Mucopolysaccharidosis Type IIIB and MPS IIIB (Sanfilippo B Syndrome), run by Spruce Biosciences at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 5 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: status not confirmed, as of the sponsor's last update on 6 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
Results are not available in the source record.
How can a doctor refer a patient or contact the research team?
Contact April Freeman (415-343-5986, EA@sprucebio.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 6 Oct 2026.