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Abstract
Objective: To determine the effect of enzyme replacement therapy (ERT) after 5 years and to identify predictors for a favorable response because few data are available on the long-term efficacy of ERT in Pompe disease.
Methods: We included 102 adult patients with Pompe disease in a nationwide, prospective cohort study. We assessed muscle strength (manual muscle testing with Medical Research Council [MRC] grading, handheld dynamometry [HHD]), muscle function (6-minute walk test, Quick Motor Function Test), daily life activities (Rasch-Built Pompe-Specific Activity [R-PAct] Scale), and pulmonary function (forced vital capacity [FVC] in upright and supine positions, maximum inspiratory and expiratory pressures) at 3- to 6-month intervals before and after the start of ERT. Data were analyzed with linear mixed-effects models for repeated measurements.
Results: Median follow-up duration was 6.1 years (range 0.4–7.9 years), of which 5.0 years (range 0.2–7.3 years) were during ERT. Treated patients had better muscle strength (MRC sum score +6.6 percentage points [pp]; HHD sum score +9.6 pp, both p < 0.0001), activity levels (R-PAct +10.8 pp, p < 0.002), and pulmonary function (FVC upright +7.3 pp, FVC supine +7.6 pp, both p < 0.0003) than expected for their untreated disease course. Walking distance improved (416 vs 376 m at baseline, p = 0.03). The largest increase was seen during the first 2 to 3 years of treatment. Response to treatment was similar between groups regardless of sex, age, or disease duration.
Conclusions: Long-term ERT positively affects muscle strength, pulmonary function, and daily life activities in adult patients with Pompe disease, with a peak effect at ≈2 to 3 years of treatment.
Classification of evidence: This study provides Class IV evidence that for patients with Pompe disease, long-term ERT positively affects muscle strength, pulmonary function, and daily life activities.
GLOSSARY
- ERT=
- enzyme replacement therapy;
- FVC=
- forced vital capacity;
- HHD=
- handheld dynamometry;
- IAR=
- infusion-associated reaction;
- MEP=
- maximum expiratory pressure;
- MIP=
- maximum inspiratory pressure;
- pp=
- percentage points;
- QMFT=
- Quick Motor Function Test;
- R-PAct=
- Rasch-Built Pompe-Specific Activity;
- 6MWT=
- 6-minute walk test
Footnotes
Go to Neurology.org for full disclosures. Funding information and disclosures deemed relevant by the authors, if any, are provided at the end of the article.
Supplemental data at Neurology.org
- Received April 29, 2017.
- Accepted in final form September 18, 2017.
- © 2017 American Academy of Neurology
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