The following article features coverage from the 17th Annual WORLDSymposium meeting. Click here to read more of MPR’s conference coverage.

Disease progression appears to occur at a slower rate in patients with mucopolysaccharidosis (MPS) VI who received galsulfase enzyme replacement therapy (ERT) in infancy compared with those who did not, according to research presented the 17th Annual WORLDSymposium.          

The aim of this multicenter, prospective analysis was to determine the long-term outcomes of treatment of MPS VI patients with galsulfase beginning in infancy. To do this, the study authors utilized data obtained from a phase 4 study (ASB-008, Identifier: NCT00299000) as well as clinical data collected at least 5 years after the study was completed. The analysis included 3 patients (Patients 1, 2, and 4) who had classical MPS VI and were 0.7, 0.3, and 1.1 years old at the start of treatment and 10.5, 7.9, and 10.5 years, respectively, at the time of follow-up.

“At follow-up, standing height was within Centers for Disease Control and Prevention [CDC] normal limits for [Patient] 4 (133.5cm, z-score -1.1) and below normal for [Patients] 1 (117.7cm, z-score -3.6) and 2 (109.3 cm, z-score -3.3),” the study authors reported. Standing heights were found to be around the 90th percentile in Patients 1 and 2 and above the 95% percentile in Patient 4, as compared to growth curves for untreated patients. Findings of the analysis also revealed normal 6-minute walking distance based on age/height for Patients 1 (550m) and 4 (506m) but below normal for Patient 2 (340m). Normal lung volumes (FVC and FEV1) were found to be preserved in subject 2 only. All patients showed relatively stable cardiac involvement.

“Since ASB-008, [Patient] 1 developed conductive hearing loss, [Patient] 2 showed improved hearing in 1 ear and worse in the other; [Patient] 4 has periodic reversible hearing loss due to otitis,” the authors added.

Analysis at follow-up also revealed that pain was not reported on the EuroQol 5 dimensions, 5 levels questionnaire or the Child Health Assessment Questionnaire by any patient. Hepatosplenomegaly was found to have either resolved or remained absent in all patients. Additionally, functional dexterity was reported to be as expected for age, according to the 16-hold peg test. Corneal clouding and moderate skeletal disease was observed in all patients.

“These results suggest a positive impact of continuous ERT since infancy on the clinical course of MPS VI,” the study authors stated. While less growth impairment was observed, in the long term, early treatment did not prevent skeletal or eye disease progression.

Disclosure: Some authors have declared affiliations with or received funding from the pharmaceutical industry. Please refer to the original study for a full list of disclosures.


Johnson J, Garcia P, Martin K, et al. Poster 109 – Long-term outcomes of patients with mucopolysaccharidosis type VI treated with galsulfase enzyme replacement therapy since infancy. Presented at: 17th Annual WORLDSymposium; February 8-12, 2020. Poster #109.