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Background and purpose: Two novel enzyme replacement therapies (ERTs), studied in phase 3 trials in late‐onset Pompe patients, reached marketing authorization by the European Medicines Agency in 2022 and 2023. The European Pompe Consortium (EPOC) updates and extends the scope of the 2017 recommendations for starting, switching and stopping ERT. Methods: The European Pompe Consortium consists of 25 neuromuscular and metabolic experts from eight European countries. This update was performed after an in‐person meeting, three rounds of discussion and voting to provide a consensus recommendation. Results: The patient should be symptomatic, that is, should have skeletal muscle weakness or respiratory muscle involvement. Muscle magnetic resonance imaging findings showing substantial fat replacement can support the decision to start in a patient‐by‐patient scenario. Limited evidence supports switching ERT if there is no indication that skeletal muscle and/or respiratory function have stabilized or improved during standard ERT of 12 months or after severe infusion‐associated reactions. Switching of ERT should be discussed on a patient‐by‐patient shared‐decision basis. If there are severe, unmanageable infusion‐associated reactions and no stabilization in skeletal muscle function during the first 2 years after starting or switching treatment, stopping ERT should be considered. After stopping ERT for inefficacy, restarting ERT can be considered. Six‐monthly European Pompe Consortium muscle function assessments are recommended. Conclusions: The triple‐S criteria on ERT start, switch and stop include muscle magnetic resonance imaging as a supportive finding and the potential option of home infusion therapy. Six‐monthly long‐term monitoring of muscle function is highly recommended to cover insights into the patient's trajectory under ERT. [ABSTRACT FROM AUTHOR]

Duvoglustat HCl (AT2220, 1-deoxynojirimycin) is an investigational pharmacological chaperone for the treatment of acid α-glucosidase (GAA) deficiency, which leads to the lysosomal storage disorder Pompe disease, which is characterized by progressive accumulation of lysosomal glycogen primarily in heart and skeletal muscles. The current standard of care is enzyme replacement therapy with recombinant human GAA (alglucosidase alfa [AA], Genzyme). Based on preclinical data, oral co-administration of duvoglustat HCl with AA increases exposure of active levels in plasma and skeletal muscles, leading to greater substrate reduction in muscle. This phase 2a study consisted of an open-label, fixed-treatment sequence that evaluated the effect of single oral doses of 50 mg, 100 mg, 250 mg, or 600 mg duvoglustat HCl on the pharmacokinetics and tissue levels of intravenously infused AA (20 mg/kg) in Pompe patients. AA alone resulted in increases in total GAA activity and protein in plasma compared to baseline. Following co-administration with duvoglustat HCl, total GAA activity and protein in plasma were further increased 1.2- to 2.8-fold compared to AA alone in all 25 Pompe patients; importantly, muscle GAA activity was increased for all co-administration treatments from day 3 biopsy specimens. No duvoglustat-related adverse events or drug-related tolerability issues were identified.

ABSTRACT Introduction: Acid α-glucosidase deficiency, that is, Pompe disease, is a glycogenosis for which enzyme replacement therapy (ERT) is available. It is not known whether patients diagnosed at an asymptomatic stage should be treated to prevent progression of the disease. Methods: We investigated 7 patients with asymptomatic Pompe disease identified from the French Pompe registry. Results: The patients had a mean age of 45 (range 24-75) years, a median follow-up duration of 2 (range 1-22) years, and normal clinical examination, pulmonary function tests (PFTs), and echocardiography. All presented with at least 1 subclinical abnormality, including hyperCKemia, vacuolar myopathy, and muscle MRI abnormalities, suggesting that subclinical myopathy was present in all cases. Conclusions: Asymptomatic Pompe disease may remain clinically silent for decades, and affected patients should be monitored closely for overt myopathy using clinical examination, PFTs, and muscle MRI to determine when to start ERT. Muscle Nerve 51: 884-889, 2015 [ABSTRACT FROM AUTHOR]

Abstract: To describe muscle involvement on whole-body MRI scans in adult patients at different stages of late-onset Pompe disease. Twenty patients aged 37 to 75 were examined. Five were bedridden and required ventilatory support. Axial and coronal T1 turbo-spin-echo sequences were performed on 1.5T or 3T systems. MRI was scored for 47 muscles using Mercuri’s classification. Whole-body scans were obtained with a mean in-room time of 29min. Muscle changes consisted of internal bright signals of fatty replacement without severe retraction of the muscles’ corpus. Findings were consistent with previous descriptions of spine extensors and pelvic girdle, but also provided new information on recurrent muscle changes particularly in the tongue and subscapularis muscle. Moreover thigh involvement was more heterogeneous than previously described, in terms of distribution across muscles as well as with respect to the overall clinical presentation. Whole-body MRI provides a very evocative description of muscle involvement in Pompe disease in adults. [Copyright &y& Elsevier]