Results of 14-year-long Enzyme Replacement Therapy in a Patient with Mucopolysaccharidosis Type II: Clinical Case

Background. Mucopolysaccharidosis type II (MPS II) is a rare hereditary disease from the group of lysosomal storage diseases, with progressive course. There is effective enzyme replacement therapy (ERT) for this disease, it prevents the development of severe complications and improves patients’ quality of life. Long-term follow-up of health changes in individuals on ERT is required for evaluating the treatment impact on disease progression and eventually on the quality of life of the patient and his family.

Clinical case description. Results of 14-year-long follow-up of the patient with MPS II who was the first patient on ERT with idursulfase in Russia are presented. Improvement of growth, decrease in ENT-organs infections frequency, liver and spleen sizes decrease, general stabilization, no progression in cardiovascular and respiratory events, normal levels of glycosaminoglycans in urine are shown.

Conclusion. Long-term therapy with idursulfase in severe MPS II stabilizes the patient’s somatic condition, prevents the development of severe complications in cardiovascular and respiratory systems, improves the quality of life of the patient and his family. Urinary glycosaminoglycans level decrease is the important indicator of the therapy efficacy along with overall patient's somatic state.

1. Kakkis E, Marsden D. Urinary glycosaminoglycans as a potential biomarker for evaluating treatment efficacy in subjects with mucopolysaccharidoses. Mol Genet Metab. 2020;130(1):7–15. doi: https://doi.org/10.1016/j.ymgme.2020.02.006

2. Yee KS, Alexanderian D, Feng Y, et al. Impact of the Timing of Enzyme Replacement Therapy Initiation and Cognitive Impairment Status on Outcomes for Patients with Mucopolysaccharidosis II (MPS II) in the United States: A Retrospective Chart Review. J Health Econ Outcomes Res. 2022;9(2):67–76. doi: https://doi.org/10.36469/001c.36540

3. Khan SA, Peracha H, Ballhausen D, et al. Epidemiology of mucopolysaccharidoses. Mol Genet Metab. 2017; 121(3):227–240. doi: https://doi.org/10.1016/j.ymgme.2017.05.016

4. Wikman-Jorgensen PE, López Amorós A, Peris García J, et al. Enzyme replacement therapy for the treatment of Hunter disease: A systematic review with narrative synthesis and meta-analysis. Mol Genet Metab. 2020;131(1-2):206–210. doi: https://doi.org/10.1016/j.ymgme.2020.07.005

5. Whiteman DA, Kimura A. Development of idursulfase therapy for mucopolysaccharidosis type II (Hunter syndrome): the past, the present and the future. Drug Des Devel Ther. 2017;11:2467–2480. doi: https://doi.org/10.2147/dddt.s139601

6. Muenzer J, Botha J, Harmatz P, et al. Evaluation of the longterm treatment effects of intravenous idursulfase in patients with mucopolysaccharidosis II (MPS II) using statistical modeling: data from the Hunter Outcome Survey (HOS). Orphanet J Rare Dis. 2021;16(1):456–469. doi: https://doi.org/10.1186/s13023-021-02052-4

7. Tomita K, Okamoto S, Seto T, Hamazaki T. Real world longterm outcomes in patients with mucopolysaccharidosis type II: A retrospective cohort study. Mol Genet Metab Rep. 2021;29: 1008–1016. doi: https://doi.org/10.1016/j.ymgmr.2021.100816

8. Bratulic S, Limeta A, Maccari F, et al. Analysis of normal levels of free glycosaminoglycans in urine and plasma in adults. J Biol Chem. 2022;298(2):101575. doi: https://doi.org/10.1016/j.jbc.2022.101575

9. Concolino D, Deodato F, Parini R. Enzyme replacement therapy: efficacy and limitations. Ital J Pediatr. 2018;44(2):120. doi: https://doi.org/10.1186/s13052-018-0562-1

10. Vashakmadze ND, NamazovaBaranova LS, Zhurkova NV, et al. Mucopolysaccharidosis type II: Enzyme Replacement Therapy Efficiency. Voprosy sovremennoi pediatrii — Current Pediatrics. 2019;18(6):485–490. (In Russ). doi: https://doi.org/10.15690/vsp.v18i6.2070

11. Grant N, Sohn YB, Ellinwood NM, et al. Timing is everything: Clinical courses of Hunter syndrome associated with age at initiation of therapy in a sibling pair. Mol Genet Metab Rep. 2022;30:100845. https://doi.org/10.1016/j.ymgmr.2022.100845