Clinical Characteristics and Healthcare Resource Utilization for Patients with Mucopolysaccharidosis II (MPS II) in the United States: A Retrospective Chart Review

Abstract

Background: Mucopolysaccharidosis II (MPS II; Hunter syndrome) is a rare, X-linked, life-limiting lysosomal storage disease characterized by a deficiency in the activity of the enzyme iduronate-2-sulfatase. Accumulation of glycosaminoglycans in tissues and organs throughout the body causes cellular damage, leading to multisystemic disease manifestations. Patients generally require multidisciplinary care across a wide range of specialties. Objectives: The aims of this study were to assess the healthcare needs of patients with MPS II and to explore the impact of treatment on disease burden and healthcare resource utilization. Methods: A retrospective review of medical charts from 19 US sites was performed. Data were analyzed from 140 male patients diagnosed with MPS II (defined as a documented deficiency in iduronate-2-sulfatase) between 1997 and 2017. The prevalence and age at onset of clinical manifestations and extent and frequency of healthcare resource use were evaluated. Results: Of the patients in this study, 77.1% had received enzyme replacement therapy with intravenous idursulfase and 62.1% had cognitive impairment. The clinical burden among patients was substantial: almost all patients had ear, nose, and throat abnormalities (95.7%); musculoskeletal abnormalities (95.0%); and joint stiffness or abnormalities (90.7%). Of the most prevalent disease manifestations, facial dysmorphism and hepatosplenomegaly were documented the earliest (median age at first documentation of 3.8 years in both cases). Hospitalizations, emergency department visits, and outpatient visits were reported for 51.2%, 58.5%, and 93.5% of patients, respectively, with a frequency of 0.1, 0.2, and 3.0 per patient per year, respectively. Surgery was also common, with 91.1% of patients having undergone at least 1 surgical procedure. The clinical burden and prevalence and frequency of resource use were generally similar in patients who had received enzyme replacement therapy and in those who had not. Conclusions: These results add to our understanding of the natural history of MPS II and indicate that the disease burden and healthcare needs of patients with this progressive disease are extensive. Increased understanding of disease burden and resource use may enable the development of models of healthcare resource utilization in patients with MPS II and contribute to improvements in disease management and patient care.

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

“…24,25 The clinical needs and HRU of 140 patients with MPS II were previously evaluated in a retrospective chart review performed in the United States over a 20-year period (1997-2017). 23 This study showed that both disease burden and HRU in these patients are high. 23 Furthermore, the clinical burden and HRU were shown to be similar between patients who received ERT with IV idursulfase (n = 108) and those who had never received ERT (n = 32); however, this comparison was limited by the heterogeneity of the patient population.…”

“…23 This study showed that both disease burden and HRU in these patients are high. 23 Furthermore, the clinical burden and HRU were shown to be similar between patients who received ERT with IV idursulfase (n = 108) and those who had never received ERT (n = 32); however, this comparison was limited by the heterogeneity of the patient population. 23 To inform healthcare decision-making, there is a need for greater understanding of the influence of timing of ERT initiation and CI status on the outcomes of patients with MPS II.…”

“…Details of the study design and the study population have been previously described in full. 23 Study sites were specialist clinics and were selected based on responses to a suitability questionnaire that determined the interests of the study investigator (someone who was a specialist in the treatment of patients with MPS II at any one of a number of major US-based medical sites), the number of eligible patients with MPS II, whether there was a suitable ethics approval process in place, and whether staff had capacity for the necessary data extraction. Eligible patients were identified by the participating physicians and site staff.…”

“…23 Furthermore, the clinical burden and HRU were shown to be similar between patients who received ERT with IV idursulfase (n = 108) and those who had never received ERT (n = 32); however, this comparison was limited by the heterogeneity of the patient population. 23 To inform healthcare decision-making, there is a need for greater understanding of the influence of timing of ERT initiation and CI status on the outcomes of patients with MPS II. Here, we report further analysis of the retrospective chart review to assess the impact of timing of ERT initiation (before the age of 3 years, between the ages of 3 and 6 years, or older than 6 years) and CI status on the clinical characteristics and HRU of patients with MPS II.…”

“…[16][17][18][19] Regardless of MPS II presentation (neuronopathic or non-neuronopathic), patients experience a high disease burden, resulting in extensive healthcare resource utilization (HRU) and reduced quality of life. [20][21][22][23] Treatment for MPS II is available in the form of enzyme replacement therapy (ERT) with recombinant human I2S (idursulfase; marketed as ELAPRASE®, Takeda Pharmaceuticals U.S.A., Inc., Lexington, Massachusetts). 24 Idursulfase is administered weekly as an intravenous (IV) infusion and has been linked to increased survival and improvements in many somatic disease manifestations, including joint stiffness, liver and spleen enlargement, respiratory symptoms, and heart hypertrophy.…”