Characteristics of patients with mucopolysaccharidosis type II who have received a bone marrow transplant: Data from the Hunter Outcome Survey

Abstract

Mucopolysaccharidosis type II (MPS II Hunter syndrome) is a rare, life-limiting, X-linked lysosomal storage disease. The Hunter Outcome Survey (HOS) is a Shire-sponsored, global, observational registry initiated in 2005 that collects real-world data on the natural history of MPS II and long-term treatment with enzyme replacement therapy (ERT) with idursulfase. Patients receiving other forms of pharmacological ERT are excluded from HOS but individuals who have received a bone marrow transplant (BMT) may be enrolled. This analysis examined the characteristics of 36 male patients in HOS from Europe and North America who had received a BMT (March 2018 data). In total, 22 patients (61.1%) were European and 14 (38.9%) were North American. Twenty-seven patients (75%) were followed prospectively in HOS 9 (25%) were enrolled after their death (followed retrospectively). Median (10th percentile, 90th percentile) ages at symptom onset, diagnosis and last visit were 0.8 (0.1, 3.0) years (n=26), 2.5 (0.8, 5.0) years (n=35) and 15.2 (4.9, 28.4) years (n=27), respectively patients were aged 2.6 (0.7, 4.5) years at BMT (n=10). Fourteen patients (38.9%) had received at least one idursulfase infusion, 16 (44.4%) had not received idursulfase idursulfase treatment status was unknown for six patients (16.7%). Of seven patients with data available on the relative timing of idursulfase treatment and BMT, six started idursulfase before BMT and one started idursulfase after BMT. Median time between idursulfase start and BMT was 3.5 (−173.5, 24.3) months (n=7). Cognitive impairment at any time was reported for 21 patients (58.3% n=36). In total, 13/36 patients died median age at death was 8.8 (3.4, 17.6) years. The most common cause of death was graft versus host disease/transplant complications (n=4) followed by respiratory failure (n=3). These long-term data from HOS provide valuable information on patients with MPS II undergoing BMT. Shire sponsors HOS and funds medical writing support.