Exercise Capacity in Response to Enzyme Replacement Therapy in Pediatric Pompe Disease.

Study Overview
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Brief Summary
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Our aims are to investigate the acute and long term effect of ERT on exercise capacity; comparing the effect of different ERT dosages (as prescribed by the clinician according to clinical judgment) and assessing the relationship between enzyme blood level and exercise capacity. Such evaluation may allow a more objective quantification of the response to ERT.

Detailed Description
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Pompe disease is a rare autosomal recessive metabolic myopathy caused by reduced or absence activity of the lysosomal enzyme acid alpha-glucosidase (GAA). Enzyme replacement therapy (ERT) with Myozyme has significantly improved the prospect of patients with infantile Pompe disease (IPD). Most IPD patients show clinical improvement on therapy, but deteriorate at different time points, raising the possibility that increasing drug delivery might halt the progression of the disease. Data on the effects of ERT therapy on physiological variables related to exercise tolerance is scarce. Our aims are to investigate the acute and long term effect of ERT on exercise capacity; comparing the effect of different ERT dosages (as prescribed by the clinician according to clinical judgment) and assessing the relationship between enzyme blood level and exercise capacity. Such evaluation may allow a more objective quantification of the response to ERT. Methods: A retrospective - prospective study evaluating pediatric patients with Pompe before and 2 days after ERT on multiple occasions and different dosing. Evaluation included cardiopulmonary exercise testing (CPET), 6 minute-walking test (6MWT), motor function test (GMFM-88) and self-collected blood samples (on a Guthrie card) for enzyme blood levels.

Official Title
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Acute and Long Term Evaluation of Exercise Capacity in Response to Enzyme Replacement Therapy in Pediatric Pompe Disease.

Conditions
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Pompe Disease Infantile-Onset

Intervention / Treatment
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* Diagnostic Test: Cardiopulmonary exercise testing (CPET)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Pompe patients >5 years that have been on alpha-glucosidase (GAA). Exclusion Criteria: Oxygen saturation > 90% in room air without ventilatory assistance. Patients will be excluded if they required any invasive ventilation or if they required noninvasive ventilation while awake and upright

Ages Eligible for Study
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Minimum Age: 5 Years
Maximum Age: 18 Years

Sexes Eligible for Study
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All

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Pediatric Pompe patients<br>A retrospective - prospective study evaluating pediatric patients with Pompe before and 2 days after ERT on multiple occasions and different dosing. Evaluation included cardiopulmonary exercise testing (CPET), 6 minute-walking test (6MWT), motor function test (GMFM-88) and self-collected blood samples (on a Guthrie card) for enzyme blood levels. | Diagnostic Test: Cardiopulmonary exercise testing (CPET)<br>* CPET using a cycle ergometer (COSMED, Rome, Italy) beginning with a no resistance warm up lasting 1 to 3 minutes and followed with an incrementing resistance adapted to the patient's functional capacities according to the examiner's free judgment and ranging from no resistance (20 Rounds Per Minute (RPM)/minute) 5 to 20 Watts/minute on ramps or by successive stages<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Exercise capacity | Oxygen uptake evaluated by cardiopulmonary exercise testing (CPET) | 1-6 years | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Six minute walk test | The distance gained after six minute of habitual walking. | 1-6 years | 
| Motor function test | Motor function test (GMFM-88) as assessed by experience physiotherapy. | 1-6 years | 
| GAA enzyme level | Self-collected blood samples (on a Guthrie card) for lysosomal enzyme acid alpha-glucosidase (GAA) blood levels. | 1-6 years |