ClinicalTrials.gov record NCT05492799
Safety, Tolerability and Efficacy of ICV AX 250 Treatment in MPS IIIB -OLE
Open-Label Multicenter Extension Study to Further Evaluate Safety, Tolerability and Efficacy of Intracerebroventricular AX 250 Treatment in Mucopolysaccharidosis Type IIIB (MPS IIIB, Sanfilippo Syndrome Type B) Patients
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AI-written from the registry record, not the study's own wording. May contain errors or omissions. Check the registry text on this page and the original record ↗ before acting on it.
This open-label extension study gives AX 250 by intracerebroventricular (ICV) infusion every other week for up to 144 weeks to people with MPS IIIB who completed Study 250-202. It collects neurocognitive, communication, adaptive behavior, quality-of-life measures, imaging, biochemical markers, and safety data. Participation requires completion of 240 weeks of Study 250-202 and enrollment within 8 weeks of dosing completion; some people (for example those who received other gene/stem-cell/enzyme therapies, have poorly controlled seizures, or have hydrocephalus/ventricular shunts) are excluded.
What it is studying. The study tests the safety, tolerability, and effects of long-term intracerebroventricular AX 250 on neurocognitive scores, behavior, imaging, and biochemical markers in people with MPS IIIB.
What the researchers hope to learn. To evaluate the safety and tolerability of ICV AX 250 and to measure its effects on neurocognitive function, communication, adaptive behavior, quality of life, imaging characteristics, and biochemical markers over up to 144 weeks.
What this study is about
The study's own summary, as published on ClinicalTrials.gov. Underlined terms have a short explanation.
This is a Phase 3B/4, multicenter, multinational, open label study to further evaluate intracerebroventricular (ICV) delivered AX 250 treatment in MPS IIIB subjects that complete Study 250-202 for up to an additional 3 years (144 weeks) of treatment with AX 250 administered by ICV infusion every other week. Subjects will be evaluated for neurocognitive function, communication, adaptive behavior, quality of life, imaging characteristics and biochemical markers of disease burden. Safety will be assessed by adverse events, clinical labs, and physical exams.
Interventions being studied
Being studied in this trial does not mean the treatment or procedure is approved or available for this condition.
- Drug
- AX 250
Eligibility
The criteria exactly as listed on ClinicalTrials.gov. Only the study team can say whether they apply to you.
Inclusion criteria
- Must have completed 240 weeks of Study 250-202 and enter 250-401 within 8 weeks of dosing completion.
- Provides written informed consent from parent or legal guardian and assent from subject, if required
- Has the ability to comply with protocol requirements in the opinion of the investigator
- If female with childbearing potential, must have a negative pregnancy test at the Screening visit and be willing to have additional pregnancy tests during the study
Exclusion criteria
- Has (1) a cognitive age equivalent (AEq ) score ≤ 18 months, (2) a development quotient (DQ) score ≤ 20, and (3) no evidence of improvement during the 250-202 study in secondary or exploratory efficacy endpoints
- Would not benefit from enrolling in the study in the opinion of the investigator
- Has received stem cell, gene therapy or enzyme replacement therapy (other than AX 250) for MPS IIIB
- Has a history of poorly controlled seizure disorder
- Is prone to complications from ICV drug administration including patients 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 study
- Has a medical condition or extenuating circumstance that, in the opinion of the investigator, might compromise the subject's ability to comply with protocol requirements, the subject's well-being or safety, or the interpretability of the subject's clinical data
Study description and what participation involves
The registry record has no detailed description beyond the summary above.
AI summaryWhat participation may involve, in plain languageShow ▾Hide ▴
AI-written from the registry record, not the study's own wording. May contain errors or omissions. Check the registry text on this page and the original record ↗ before acting on it.
Participants receive AX 250 by intracerebroventricular (ICV) infusion every other week for up to 144 weeks (about 3 years). They will have regular safety monitoring (adverse-event checks, physical exams, and blood tests), periodic imaging, and repeated assessments of thinking/learning (neurocognition), communication, adaptive behavior, quality of life, and biochemical disease markers. Females of childbearing potential will have pregnancy testing during the study. Participation requires informed consent/assent and ongoing ability to attend visits and comply with study procedures.
How the study is structured. Single-group, open-label extension: all participants receive AX 250 (300 mg as described in the record) by ICV infusion every other week and are followed for up to 144 weeks. Follow-up includes regular clinic visits with neurocognitive assessments, questionnaires about communication and quality of life, imaging, laboratory tests, and safety monitoring.
Questions you could ask
These questions are suggestions for a conversation with the study team or your own clinician, not advice.
- The registry lists this study under MPS III B. Does it apply to my diagnosis?
- The registry says participants are enrolled by invitation. Who decides who is invited, and how?
- The listed sites are in Colombia, Germany, Turkey, United Kingdom, United States. Is any of them reachable for me, and does the study help with travel?
- Which of the eligibility criteria would need to be checked with tests before I could join?
More on Sanfilippo syndrome
Important dates
- Study start
- Dec 2, 2022
- Primary completion
- October 2027 (estimated)
- Study completion
- December 2027 (estimated)
- Target enrollment
- 15 participants (estimated)
- Last updated on registry
- Aug 9, 2023
- Data verified
- Oct 10, 2026
Sponsor and research team
The lead sponsor funds and oversees the trial. A pharmaceutical or biotech company sponsor typically means the study is testing that company's drug or device; a hospital, university, or government agency usually indicates investigator-initiated or publicly funded research.
- Lead sponsor
- Allievex Corporation
Participating sites (6)
- UCSF Benioff Children's Hospital Oakland
Oakland, California, 94609 · United States
- UPMC Children's Hospital Pittburgh
Pittsburgh, Pennsylvania, 15224 · United States
- Fundación Cardio Infantil - Instituto de Cardiología
Bogotá · Colombia
- University Medical Center Hamburg-Eppendorf
Hamburg · Germany
- Gazi University Faculty of Medicine
Ankara · Turkey (Türkiye)
- Great Ormond Street Hospital For Children, NHS Foundation Trust
London, WC1N 3JH · United Kingdom
Terms used on this page · explanations by MedicalUpdates.ai
- open label
- No masking is used, so the assigned intervention is not deliberately hidden from participants or study staff.
- intracerebroventricular
- Given directly into the fluid-filled spaces (ventricles) inside the brain, usually through an implanted catheter or reservoir.
- adverse events
- Any unwanted medical problem that happens during a study, whether or not it was caused by the treatment. A 'serious' adverse event is one that meets specific criteria, such as causing death, being life-threatening, requiring or prolonging hospital admission, causing significant disability, or another medically important outcome.
- written informed consent
- The process of explaining a study, including its risks and what participation involves, so that a person can decide freely whether to take part. Consent is usually documented in writing, and a participant can choose to leave the study later.
- legal guardian
- A person who is legally allowed to make decisions, including consent to research, on behalf of someone who cannot consent for themselves.
- assent
- A child's or dependent adult's agreement to take part, given alongside the formal consent of a parent or legal representative.
- childbearing potential
- Studies often ask participants who could become pregnant, or could father a child, to use contraception during the study and for a period afterwards, because the effect of the treatment on a pregnancy is unknown.
- Screening visit
- The checks done before enrolment to see whether a person qualifies, such as tests, scans or a review of medical history.
- endpoints
- Something the study measures to judge its results, such as a symptom score, a blood test or survival. Outcomes are grouped as primary, secondary and sometimes exploratory.
- investigational
- A treatment that is being tested and has not been approved for this use. It may be approved for a different condition. Being studied does not mean it works or is available outside the study.
- Baseline
- Measurements taken at the start of the study, before any study treatment, so that later results can be compared with them.
- Inclusion Criteria
- The conditions a person must meet to be considered for the study, for example a confirmed diagnosis, an age range or a test result.
- Exclusion Criteria
- The conditions that rule a person out even if they meet the inclusion criteria, for example other illnesses, certain medicines or pregnancy.
The study record on this page is reproduced from ClinicalTrials.gov, a database of the U.S. National Library of Medicine, where it was submitted by the study sponsor. MedicalUpdates.ai does not own this content, is not affiliated with or endorsed by ClinicalTrials.gov, NIH, or the U.S. Government, and does not verify the record. Plain-language notes, the glossary and the questions above are added by this site; text in the boxes marked "AI summary" was written by an AI model and may contain errors. Registry records change over time. Check the original record for the current version and discuss eligibility or participation with a qualified healthcare professional.
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