Real-world treatment with elosulfase alfa in patients with MPS IVA is associated with improved endurance over time

To assess the real-world effectiveness of enzyme replacement therapy (ERT; elosulfase alfa) on endurance in the treatment of mucopolysaccharidosis type IVA (MPS IVA) using cross-sectional data.

The 6-minute walk test (6MWT) distances of ERT-treated and untreated participants from the Morquio A Registry Study and Morquio A Clinical Assessment Program were described for age groups of interest (5 to <7 years, 9 to <11 years, 14 to <16 years, and 20 to <30 years). Linear and quantile univariate regression were performed to explore variables associated with 6MWT (ERT, sex, age, standing height, body weight, region, and race). Multivariate regression analyses were performed using covariates identified in univariate analyses (P < .10), adjusting for confounders.

A total of 471 participants were included; baseline characteristics were similar within age groups. Median 6MWT distances were numerically greater in ERT-treated versus untreated participants within each age group. Quantile regression adjusting for multiple factors indicated a consistent trend of improved 6MWT with ERT treatment. Standing height was also associated with longer 6MWT in the multivariate quantile analysis, except in participants aged 5 to <7 years.

This analysis assessed associations between ERT exposure and endurance to confirm the real-world, long-term effectiveness of elosulfase alfa in participants with MPS IVA.