Neutralizing Antibody Seroprevalence Study With a Retrospective Component in Participants With Late-Onset Pompe Disease

Study Overview
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Brief Summary
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The purpose of this study is to obtain information pertaining to the occurrence of antibodies to investigational SPK-3006 capsid and GAA, GAA activity and GAA antigen levels in the usual care setting of Late-Onset Pompe Disease (LOPD) participants on an enzyme replacement regimen. Additionally, a careful evaluation of laboratory and functional testing in patients with LOPD may provide information to better understand the disease features and better drive the design of a future interventional investigational gene therapy trial. An understanding of the underlying status of liver and muscle health in individuals with LOPD may also inform best surveillance during the conduct of gene therapy trials.

Official Title
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A Multi-Center, Low-Interventional Study With a Retrospective Component in Participants With Late-Onset Pompe Disease

Conditions
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LOPD, Pompe Disease, Pompe Disease (Late-onset), Glycogen Storage Disease Type 2, Lysosomal Storage Diseases, Acid Maltase Deficiency

Intervention / Treatment
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* Diagnostic Test: Neutralizing Antibody to SPK-3006 capsid


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Provide written informed consent and authorization to use protected health information in accordance with national and local privacy regulations Male or females ≥18 years of age Currently on ERT using regular recombinant human GAA infusions for at least 18 months prior to screening Documented history of clinically moderate late-onset Pompe disease. Exclusion Criteria: History of HIV infection Requires any invasive ventilation (other than BiPAP at night) or noninvasive ventilation while awake and upright Previously received SPK-3006 Previously dosed with any investigational or approved gene therapy product at any time or treated with an investigational drug within the last 12 weeks (vaccination studies are accepted) Any concurrent clinically significant condition that would not allow the potential participant to complete the Day 1 examinations, or other condition that, in the opinion of the Investigator and/or Sponsor, makes the subject unsuitable for participation in the study Unable or unwilling to comply with the schedule of visits and/or study assessments described in the clinical protocol.

Ages Eligible for Study
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Minimum Age: 18 Years

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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Design Details

Primary Purpose: Screening
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Participants with Late Onset Pompe disease<br>This is a multi-center, low-interventional study with a retrospective component in participants with LOPD. During a single study visit, assessments including but not limited to, liver health, neutralizing antibodies to SPK-3006 capsid and GAA, anti-GAA binding antibodies, GAA activity and GAA antigen levels will be performed. Additional information will be collected to provide retrospective evaluations relating to muscle and liver inflammation and/or injury. Historic data relating to Pompe disease will be collected from medical records. The retrospective and laboratory data collected may assist in providing baseline information for a future investigational gene therapy study. | Diagnostic Test: Neutralizing Antibody to SPK-3006 capsid<br>* Collected during a single study visit to establish the occurrence of neutralizing antibodies to SPK-3006 capsid in participants with LOPD on an enzyme replacement regimen.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Neutralizing Antibodies Titer to SPK-3006 capsid | The neutralizing antibodies titer to SPK-3006 is measured once prospectively at one site visit. | 1 day | 
| Occurrence of Neutralizing Antibodies to SPK-3006 capsid | The proportion of participants who have Neutralizing Antibodies to SPK-3006 capsid. | 1 day | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Anti-GAA binding antibodies Titer | Anti-GAA binding antibodies titer is measured once prospectively at one site visit. | 1 day | 
| Occurrence of Anti-GAA binding antibodies across participants | The proportion of participants who have Anti-GAA binding antibodies. | 1 day | 
| Neutralizing antibodies to circulating GAA Titer | Neutralizing antibodies to circulating GAA titer is measured once prospectively at one site visit and, if available, retrospectively from medical records that are within 24 months of signing the informed consent. | 1 day | 
| Occurrence of Neutralizing antibodies to circulating GAA | The proportion of participants who have neutralizing antibodies to circulating GAA. | 1 day | 
| GAA activity level | GAA activity level (percent of normal) is measured once prospectively at one site visit and, if available, retrospectively from medical records that are within 24 months of signing the informed consent. | 1 day | 
| GAA antigen level | GAA antigen level (percent of normal) is measured once prospectively at one site visit and, if available, retrospectively from medical records that are within 24 months of signing the informed consent. | 1 day |