Pompe disease is a rare metabolic disease caused by abnormalities in the GAA gene, which codes for acid alpha-glucosidase, also called acid maltase. The infantile-onset of the disease causes early death in the absence of enzyme replacement therapy with alglucosidase alfa (Myozyme®), administered intravenously at the usual dose of 20 mg / kg / 14 days.
In recent years, several teams have published positive results of treatment at higher doses in children. A Dutch study, with results published in June 2020, confirms this therapeutic option. It comes from the Center for Lysosomal and Metabolic Diseases in Rotterdam, the only Dutch site for the treatment of patients with Pompe disease. His team conducted a prospective study of all Dutch children with a classic childhood form of the disease treated with Myozyme® (n = 18). Six of these children started treatment at 20 mk / kg / 2 weeks, the other 12 at 40 mg / kg / week.
Respiratory, motor and survival benefits
Analysis of the data acquired between 2003 and the end of 2016 shows a trend towards better results for children treated from the start at a dose of 40 mg / kg per week, with:
- a survival rate of 92%, vs 66% for children whose treatment has started at 20 mg / kg / 2 weeks,
- a ventilator-free survival of 92%, vs 50%,
- a favorable motor development since 92% of the children in the 40 mg group acquired walking (vs 67%) and that 83% (vs 17%) were still able to walk at the end of the study, ie average age of 4.4 years.
In the 40 mg group, the 3 cross-reactive immunological material (CRIM) negative children (which corresponds to the absence of residual activity of the native GAA enzyme) were alive and able to walk at the end of the study. whether or not they received (n = 2) immuno-modulation (rituximab. methotrexate, IV immunoglobulins). On the other hand, the 2 CRIM- children in the 20 mg group died. As a final result, immunomodulation did not prevent the formation of recombinant anti-GAA antibodies in this study.
