Association of Miglustat With Swallowing Outcomes in Niemann-Pick Disease, Type C1

Importance: Niemann-Pick disease, type C1 (NPC1) is a progressive neurovisceral disease with no US Food and Drug Administration-approved therapy. Miglustat, a drug used off-label in the United States for the treatment of NPC1, appears to stabilize neurologic disease progression. Several prospective trials suggest that miglustat stabilizes oropharyngeal swallowing function; however, its effect on dysphagia and aspiration risk has not been demonstrated instrumentally. Objective: To determine if miglustat therapy is associated with stabilized swallowing dysfunction in individuals with NPC1. Design, Setting, and Participants: Patients with confirmed NPC1 diagnoses were evaluated in a single-center cohort study of NPC1 from April 1997 to November 2019. Longitudinal data from individuals with neurologic disease onset prior to age 15 years were analyzed. The study population was divided into those with neurologic disease onset in early childhood (age <6 years) and late childhood (age ≥6 years and <15 years). Analysis began September 2019. Exposures: Oral miglustat at baseline and at follow-up. Main Outcomes and Measures: Oropharyngeal swallowing function was assessed with videofluoroscopic swallowing studies. Overall swallowing ability and aspiration risk were evaluated using the American Speech-Language-Hearing Association National Outcome Measurement System swallowing domain and an adapted Rosenbek aspiration-penetration scale, respectively. Results: Overall, 50 participants were evaluated at baseline (median interquartile range age, 9.4 3.4-16.4 years; 26 52% female). The median (interquartile range) duration of follow-up was 3.0 (1.1-4.4) years. Miglustat use was associated with decreased odds of worse American Speech-Language-Hearing Association National Outcome Measurement System swallowing domain outcomes in all 3 subsets (overall: odds ratio OR, 0.09 95% CI, 0.02-0.36); P < .001; early childhood: OR, 0.17 [95% CI, 0.04-0.67; P = .01; late childhood: OR, 0.05 95% CI, 0.01-0.29; P = .001). Miglustat use was associated with decreased odds of worse Rosenbek aspiration-penetration scale outcomes in the overall cohort (OR, 0.28 95% CI, 0.08-0.95; P = .04) but not in each subgroup (early childhood: OR, 0.27 95% CI, 0.06-1.22; P = .09; late childhood: OR, 0.38 95% CI, 0.06-2.33; P = .29). Conclusions and Relevance: These data suggest that miglustat use is associated with stabilized swallowing function and reduced aspiration risk in NPC1, thus supporting its use in this population. In addition, these data demonstrate that a quantification of swallowing dysfunction can be used as a clinically relevant, functional outcome measure in future therapeutic trials in NPC1.