|E.1 Medical condition or disease under investigation
|Medical condition(s) being investigated
|MPS IIIB is a devastating lysosomal storage disease, caused by a N-α-acetylglucosaminidase (NAGLU) gene defect. Infants with MPS IIIB appear normal at birth, but the disease is relentlessly progressive, with deterioration of social and adaptive abilities, neurocognitive decline, and premature death. Death typically occurs by end of the second or beginning of the third decade. Quite importantly, there is no treatment currently available for the disease.
|Medical condition in easily understood language
|Mucopolysaccharidosis type IIIB is a genetic disease in children, caused by the toxicity of an accumulation of substances in the body that generate a progressive deterioration.
|Diseases [C] - Congenital, Hereditary, and Neonatal Diseases and Abnormalities [C16]
|E.1.2 Medical condition or disease under investigation
|System Organ Class
|10010331 - Congenital, familial and genetic disorders
|Condition being studied is a rare disease
|E.2 Objective of the trial
|Main objective of the trial
|The primary objective of the study is to evaluate the long-term safety/tolerability of ABO-101 in patients with MPS IIIB.
|Secondary objectives of the trial
|The secondary objective is to evaluate the neurocognitive evolution of patients with MPS IIIB treated with ABO-101.
|Trial contains a sub-study
|Principal inclusion criteria
|• Participants that have completed a prior clinical trial involving the administration of ABO-101.
• Parent(s)/legal guardian(s) of participant willing and able to complete the informed consent process and comply with study procedures and visit schedule.
|Principal exclusion criteria
|• Planned or current participation in another clinical trial that may confound the safety or efficacy evaluation of ABO-101 during this study.
• Any other situation that precludes the participant from undergoing procedures required in this study.
|E.5 End points
|Primary end point(s)
|Long-term product safety as defined by the incidence, type, and severity of Adverse Events (AEs) and Serious Adverse Events (SAEs).
|Timepoint(s) of evaluation of this end point
|Safety will be evaluated along the entire trial for 3 years.
|Secondary end point(s)
|• Neurocognitive evolution based on Age Equivalent assessments included in the prior clinical trial including:
- Change from baseline (in prior trial) in the Age Equivalent and Developmental Quotient (DQ) after treatment compared to Natural History Study data calculated by the Mullen Scales of Early Learning or the Kaufman Assessment Battery for Children; Second Edition, based on chronological and developmental age [Time frame: Month 30, 36, 42, 48, 60]
- Change from baseline (in prior trial) in the Cognitive Age Equivalent and Developmental Quotient after treatment compared to Natural History Study, calculated using the Bayley Scales of Infant and Toddler Development – Third edition or the Kaufman Assessment Battery for Children. Second Edition, based on developmental age [Time Frame: Month 30, 36, 42, 48, 60]
- Change from baseline(in prior trial) in the Adaptive Age Equivalent score after treatment compared to Natural History Study data, as assessed by parent report using the Vineland Adaptive Behavior Scale II Survey form [Time frame: Month 30, 36, 42, 48, 60]
• Quality of life based on Pediatric Quality of Life Inventory (PedsQL™ and PedsQL Grastrointestinal Symptom scales-this last one, only applicable for participants who completed these evaluations in the prior clinical trial), Parenting Stress Index, 4th Edition (PSI-4).
• Evolution on Parental Global Impression Score, Clinical Global Impression Improvement Score and Parent Symptom Score Questionnaire.
• Long-term immunological responses defined as antibody formation (humoral) and T-cell responses (cellular) against the AAV9 capsid and against the α-N-acetylglucosaminidase (NAGLU) transgene product.
• Long-term viral load, in applicable cases.
|Timepoint(s) of evaluation of this end point
|Annually (± 2 months) for three years.
|E.6 and E.7 Scope of the trial
|Scope of the trial
|Other scope of the trial description
|Trial type and phase
|Human pharmacology (Phase I)
|First administration to humans
|Other trial type description
|Therapeutic exploratory (Phase II)
|Therapeutic confirmatory (Phase III)
|Therapeutic use (Phase IV)
|E.8 Design of the trial
|Other trial design description
| Comparator of controlled trial
|Other medicinal product(s)
The trial involves single site in the Member State concerned
| The trial involves multiple sites in the Member State concerned
|The trial involves multiple Member States
|Number of sites anticipated in the EEA
|E.8.6 Trial involving sites outside the EEA
|Trial being conducted both within and outside the EEA
|Trial being conducted completely outside of the EEA
|If E.8.6.1 or E.8.6.2 are Yes, specify the regions in which trial sites are planned
|Trial has a data monitoring committee
Definition of the end of the trial and justification where it is not the last
visit of the last subject undergoing the trial
|The end of the clinical trial is defined as the Last Participant Last Visit.
|E.8.9 Initial estimate of the duration of the trial
|In the Member State concerned years
|In the Member State concerned months
|In the Member State concerned days
|In all countries concerned by the trial years
|In all countries concerned by the trial months
|In all countries concerned by the trial days