Enzymatic replacement therapy in patients with late-onset Pompe disease - 6-Year follow up.

INTRODUCTION: Late-onset Pompe disease (LOPD) is a progressive metabolic myopathy, affecting skeletal muscles, which, if untreated, leads to disability and/or respiratory failure. The enzyme replacement therapy (ERT) improves muscle strength and respiratory function and prevents disease progression. We present a 6-year follow-up of 5 patients with LOPD treated with ERT.

METHODS: Five patients with LOPD received ERT: two started treatment in 2008, other two in 2010 and one in 2011. All patients received recombinant human alpha-glucosidase in dose 20mg/kg intravenously every two weeks. Physical performance was assessed in 6-minute walk test (6MWT) and spirometry was performed to examine FVC and FEV1. Liver enzymes, CK levels were also assessed.

RESULTS: The walking distance in 6MWT increased by average 16.9±2.26% in the first three years of treatment. Similar changes were detected in spirometry: the most significant FVC increase was observed in two patients with the highest FVC values before treatment, which increased to normal values adjusted for age and sex in three years of treatment, that is by 28% and 34%. In two other patients FVC reached 88% and 76% of predicted values. ERT also improved the liver and muscle enzymes levels.

CONCLUSION: The improvements of exercise tolerance and FVC were observed in all patients in the first three years of treatment and were the most pronounced in the longest-treated patients and with the least severe neurological and respiratory symptoms. Our research suggests that early start of the ERT results in higher improvement of respiratory and ambulation functions.