The French Pompe disease (PD) registry provides useful, long-term data on the course of late-onset PD (LOPD) and patients’ responses to enzyme replacement therapy (ERT) with alglucosidase alfa, according to a report published in Neurology.
The report describes data from 210 patients and their changes in characteristics over time. Of the patients included in the registry, 72 had been followed for at least 10 years, with most experiencing a worsening of symptoms.
“We provide here a description of the characteristics of the LOPD population in France, which was made possible by the existence of the French Pompe disease registry and close collaboration between the French reference centers for rare neuromuscular and metabolic diseases,” the authors wrote.
Kaplan-Meier curves revealed a steady decline in walking abilities and respiratory function status over time. According to the curves, 70% of patients had no progression of disease related to walking ability and 80% had no change in respiratory status at 5 years. The median time for change in walking ability was 9.4 years and 14.8 years for changes in respiratory status (requiring some form of respiratory assistance).
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For the patients who had been in the registry for more than 10 years, there was a reduction in the percentage of patients who could walk without technical assistance, changing from 57% at enrollment to 36% at 10 years after inclusion. There was also an increase in the percentage of patients who required noninvasive ventilation (from 33% to 60%) and in the percentage of patients who were treated for PD (from 5% to 77%).
Progressive lower-limb weakness was the primary symptom initially reported for patients when enrolling in the study, with 50% of patients experiencing weakness in isolation and 18% experiencing it along with respiratory symptoms. Progressive limb weakness was reported at a median age of 38 years and most of the patients in the study had trouble rising to a standing position or going up stairs.
Medical Research Council (MRC) muscle scores showed that hip muscles were the most affected group in the lower limbs (median score less than 3 out of 5). Trunk muscle weakness was also observed, with a median MRC score of 2 out of 5. Manual muscle testing found the weakness was generally symmetrical and primarily affected hip flexion, extension, abduction, adduction, and trunk muscles.
Of the 210 patients in the study, 177 received ERT while 33 remained untreated. The median age of treatment initiation was 49.6 years and the median treatment duration was 103 months. The untreated group had a median duration between symptom onset and last follow-up of 12.1 years.
A total of 35 patients died during registry follow-up with a mean age of death of 66 years (range, 26 to 81 years). Most of the patients who died required ventilatory assistance (n=25) with 15 requiring around-the-clock ventilation. Respiratory failure was the main cause of death in 20 patients.
Lefeuvre C, Antonio MDE, Bouhour F, et al. Characteristics of patients with late onset Pompe disease in France: insights from the French Pompe registry in 2022. Neurology. Published online July 7, 2023. doi:10.1212/WNL.0000000000207547