A Long-term Follow-up Study of Patients With MPS IIIB Treated With ABO-101

Study Overview
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Brief Summary
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This is a multicenter, non-interventional, long-term follow-up (LTFU) study in participants who have been treated with ABO-101 in a prior trial. Eligible participants will undergo clinical evaluations at prespecified intervals for 3 years from the last visit in the prior clinical trial (up to 5 years post-treatment).

Detailed Description
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This is a multicenter, noninterventional, long-term follow-up study of patients with (Mucopolysaccharidosis IIIB) MPS IIIB who have completed a prior clinical trial involving the administration of ABO-101. This study is designed to provide LTFU in accordance with the FDA and European Medicines Agency (EMA) guidelines for patients treated with gene therapy products. The duration of the current study is 3 years for a total of up to 5 years post-treatment for these participants who rollover from a prior clinical trial of ABO-101. Participants will have a maximum of 5 annual scheduled visits with assessments as specified in the schedule of assessments.

Official Title
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A Long-term Follow-up Study of Patients With MPS IIIB From Gene Therapy Clinical Trials Involving the Administration of ABO-101 (rAAV9.CMV.hNAGLU)

Conditions
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Mucopolysaccharidosis III-B

Intervention / Treatment
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* Biological: ABO-101


Participation Criteria
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Eligibility Criteria
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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 Exclusion Criteria: Planned or current participation in another clinical trial that may confound the safety and efficacy evaluation of ABO-101 during the duration of this study Any other situation that precludes the participant from undergoing procedures required in this study
Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| ABO-101<br>Participants from prior interventional trials involving the administration of ABO-101. | Biological: ABO-101<br>* Gene therapy rAAV9.CMV.hNAGLU<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Adverse Events | Long-term product safety as defined by the incidence, type, and severity of Adverse Events (AEs) and Serious Adverse Events (SAEs) | 60 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Age Equivalent Compared to Natural History Study Data | Change from baseline in the Age Equivalent after treatment compared to Natural History Study data calculated by the Mullen Scales of Early Learning or the Kaufman Assessment Battery far Children; Second Edition, based on chronological and developmental age | AII study visits (30, 36, 42, 48, and 60 Months) | 
| Developmental Quotient Compared to Natural History Study Data calculated by the Mullen Scales of Early Learning or the Kaufman Assessment Battery for Children | Change from baseline in the 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 | AII study visits (30, 36, 42, 48, and 60 Months) | 
| Cognitive Age Equivalent Compared to Natural History Study Data | Change from baseline in the Cognitive Age Equivalent after treatment compared to Natural History Study, calculated using the Bayley Scales of lnfant and Toddler Development - Third edition or the Kaufman Assessment Battery far Children. Second Edition, based on developmental age | AII study visits (30, 36, 42, 48, and 60 Months) | 
| Developmental Quotient Compared to Natural History Study Data calculated using the Bayley Scales of lnfant and Toddler Development or the Kaufman Assessment Battery for Children | Change from baseline in the Developmental Quotient after treatment compared to Natural History Study, calculated using the Bayley Scales of lnfant and Toddler Development - Third edition or the Kaufman Assessment Battery far Children. Second Edition, based on developmental age | AII study visits (30, 36, 42, 48, and 60 Months) | 
| Adaptive Age Equivalent Compared to Natural History Study Data | Change from baseline 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 farm | AII study visits (30, 36, 42, 48, and 60 Months) | 
| Pediatric Quality of Life lnventory (PedsQL ™) | Quality of life based on Pediatric Quality of Life lnventory (PedsQL ™) applicable for participants who completed these evaluations in the prior clinical trial. | AII study visits (30, 36, 42, 48, and 60 Months) | 
| Parenting Stress lndex, 4th Edition (PSl-4) | Quality of life based on Parenting Stress lndex, 4th Edition (PSl-4). | AII study visits (30, 36, 42, 48, and 60 Months) | 
| Parental Global lmpression Scale | Evolution on Parental Global lmpression Score, applicable for patients who completed these evaluations in the prior clinical trial. | AII study visits (30, 36, 42, 48, and 60 Months) | 
| Clinical Global lmpression lmprovement Scale | Evolution of Clinical Global lmpression lmprovement Score applicable for patients who completed these evaluations in the prior clinical trial. | AII study visits (30, 36, 42, 48, and 60 Months) | 
| Parent Symptom Scale Questionnaire | Evolution on Parent Symptom Score Questionnaire applicable for patients who completed these evaluations in the prior clinical trial. | AII study visits (30, 36, 42, 48, and 60 Months) | 
| T-cell responses against the AAV9 capsid | Long-term immunological responses defined as T-cell responses against the AAV9 capsid | 60 Months | 
| T-cell responses against the α-N- acetylglucosaminidase (NAGLU) transgene product | Long-term immunological responses defined as T-cell responses against the α-N- acetylglucosaminidase transgene product. | 60 Months | 
| Antibody formation (humoral) against the α-N- acetylglucosaminidase (NAGLU) transgene product | Long-term immunological responses defined as antibody formation (humoral) against the α-N- acetylglucosaminidase (NAGLU) | 60 Months | 
| Antibody formation (humoral) against the AAV9 capsid | Long-term immunological responses defined as antibody formation (humoral) against the AAV9 capsid. | 60 Months | 
| Viral Load | Long-term viral load, in applicable cases. | AII study visits (30, 36, 42, 48, and 60 Months) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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MPS IIIB, Mucopolysaccharidosis IIIB, Sanfilippo B