Long term follow-up to evaluate the efficacy of miglustat treatment in Italian patients with Niemann-Pick disease type C.

BACKGROUND: Twenty-five patients with Niemann Pick disease type C (age range: 7 months to 44 years) were enrolled in an Italian independent multicenter trial and treated with miglustat for periods from 48 to 96 months. METHODS: Based on the age at onset of neurological manifestations patients' phenotypes were classified as: adult (n = 6), juvenile (n = 9), late infantile (n = 6), early infantile (n = 2). Two patients had an exclusively visceral phenotype. We clinically evaluated patients' neurological involvement, giving a score of severity ranging from 0 (best) to 3 (worst) for gait abnormalities, dystonia, dysmetria, dysarthria, and developmental delay/cognitive impairment, and from 0 to 4 for dysphagia. We calculated a mean composite severity score transforming the original scores proportionally to range from 0 to 1 to summarize the clinical picture of patients and monitor their clinical course. RESULTS: We compared the results after 24 months of treatment in 23 patients showing neurological manifestations. Stabilization or improvement of all parameters was observed in the majority of patients. With the exception of developmental delay/cognitive impairment, these results persisted after 48-96 months in 41 - 55% of the patients (dystonia: 55%, dysarthria: 50%, gait abnormalities: 43%, dysmetria: 41%, respectively). After 24 months of therapy the majority of the evaluable patients (n = 20), demonstrated a stabilization or improvement in the ability to swallow four substances of different consistency (water: 65%, purée: 58%, little pasta: 60%, biscuit: 55%). These results persisted after 48-96 months in 40-50% of patients, with the exception of water swallowing. Stabilization or improvement of the composite severity score was detected in the majority (57%) of 7 patients who were treated early (within 3.5 years from onset) and rarely in patients who received treatment later. CONCLUSIONS: The results of this study suggest that miglustat treatment can improve or stabilize neurological manifestations, at least for a period of time; the severity of clinical conditions at the beginning of treatment can influence the rate of disease progression. This conclusion applies particularly to patients with juvenile or adult onset of the disease. TRIAL REGISTRATION: EudraCT number 2006-005842-35.

The videofluoroscopic swallowing study shows a sustained improvement of dysphagia in children with Niemann-Pick disease type C after therapy with miglustat.

Niemann-Pick disease type C (NPC) is a rare autosomal recessive lysosomal storage disorder characterized by defective intracellular lipid trafficking, with secondary accumulation of free cholesterol, sphingosine, and glycosphingolipids. NPC is clinically characterized by a wide spectrum of manifestations with progressive visceral and neurological involvement, including dysphagia. Neurological manifestations represent the most debilitating findings. Swallowing impairment is a frequent cause of morbidity and disability in NPC patients and progressive dysphagia may be considered a marker of neurological progression. Recently substrate reduction therapy with miglustat has been proposed for the treatment of neurological manifestations in NPC patients. This observational study reports on the long-term use of miglustat in four pediatric patients with NPC and shows the efficacy of the treatment to improve or prevent dysphagia, and persistence after 3 years of treatment or more. We used a videofluoroscopic analysis of liquid barium swallowing to provide additional information on patterns of impairment of the swallowing mechanism and to detect aspiration. In three patients showing dysphagia and aspiration we observed the improvement of the swallowing function and the sustained absence of barium aspiration in the airways after miglustat treatment, while the patient with normal swallowing function at baseline did not show any deterioration. We suggest that the videofluoroscopic study of swallowing should be routinely used to monitor the effects of treatment on swallowing ability in NPC patients.