(371) Clinical and economic burden of patients with Hunter Syndrome in the United States: a retrospective cohort study

Background: : Mucopolysaccharidosis II (MPS II) is a rare genetic disease caused by the lack of iduronate-2-sulfatase enzyme leading to a buildup of complex sugars in cells. This leads to progressive damage to organs and tissues, affecting physical and cognitive development. Although idursulfase has been approved for MPS II, real-world evidence evaluating the clinical and economic burden among treated patients remains limited.

Objective: : To evaluate the clinical and economic burden of patients of MPS II treated with idursulfase in the United States.

Methods: : A retrospective study was conducted using Komodo claims data from Jan 2015-Feb 2025. The MPS II on idursulfase cohort was selected based on: 1) >1 claim of idursulfase between Jan 2017–Dec 2023 (index date); 2) >2 claims for MPS II 90-365 days apart, and within 365 days of index, 3) male, and 4) continuous enrollment 1-year pre- and up to 3-years post-index. The MPS II cohort was 1:3 direct matched to a 1% random sample of the general population in Komodo. Outcomes for clinical burden and health resource utilization (HCRU) were evaluated over the follow-up period and compared using statistical testing.

Results: : A cohort of 329 patients with MPS II on idursulfase and 987 matched controls were included. Both cohorts were primarily pediatric (mean (SD) age: 12.3 (9.3)) with a mean (SD) follow-up period of 2.94 years (0.25). The MPS II cohort had a higher proportion of patients on Medicaid compared to the matched controls (50% vs. 39%, p< 0.0001). MPS II patients had a higher proportion of patients experiencing comorbidities across all categories assessed (p < 0.0001). The most frequent comorbidities in MPS II patients were hearing loss (47%), valvular hear disease (42%), developmental delay (41%), and sleep apnea (41%). MPS II patients also experienced higher HCRU compared to the matched controls (Inpatient: 43% vs 11%, Emergency: 64% vs 43%, Surgeries: 63% vs. 29%; p< 0.0001). Mean admissions and visits in each of the healthcare settings were significantly higher among MPS II patients compared to the matched controls (Inpatient: 3.23 vs. 1.29; Outpatient: 26.56 vs. 16.13; Prescriptions: 11.50 vs. 4.99; Surgery: 1.08 vs. 0.64, respectively; p< 0.0001).

Conclusions: : Patients with MPS II on idursulfase experience significantly higher clinical and economic burden compared to the general population. These findings underscore the importance of identifying new therapies that can reduce the burden of both CNS and peripheral disease for patients with MPS II.

Sponsorship:: Denali Therapeutics