Purpose: To evaluate the safety and efficacy of recombinant human iduronate-2-sulfatase (idursulfase) in the treatment of mucopolysaccharidosis II. Methods: Ninety-six mucopolysaccharidosis II patients between 5 and 31 years of age were enrolled in a double-blind, placebo-controlled trial. Patients were randomized to placebo infusions, weekly idursulfase (0.5 mg/kg) infusions or every-other-week infusions of idursulfase (0.5 mg/kg).Efficacy was evaluated using a composite endpoint consisting of distance walked in 6 minutes and the percentage of predicted forced vital capacity based on the sum of the ranks of change from baseline. Results: Patients in the weekly and every-other-week idursulfase groups exhibited significant improvement in the composite endpoint compared to placebo (P ϭ 0.0049 for weekly and P ϭ 0.0416 for every-other-week) after one year. The weekly dosing group experienced a 37-m increase in the 6-minute-walk distance (P ϭ 0.013), a 2.7% increase in percentage of predicted forced vital capacity (P ϭ 0.065), and a 160 mL increase in absolute forced vital capacity (P ϭ 0.001) compared to placebo group at 53 weeks. Idursulfase was generally well tolerated, but infusion reactions did occur.

Purpose: This study evaluated the safety and effectiveness of long-term enzyme replacement therapy with idursulfase (recombinant human iduronate-2-sulfatase) in patients with Hunter syndrome. Methods: All 94 patients who completed a 53-week double-blinded study of idursulfase enrolled in this open-labeled extension study and received intravenous idursulfase at a dose of 0.5 mg/kg weekly for 2 years, and clinical outcomes and safety were assessed. Results: No change in percent predicted forced vital capacity was seen, but absolute forced vital capacity demonstrated sustained improvement and was increased 25.1% at the end of the study. Statistically significant increases in 6-minute walking test distance were observed at most time points. Mean liver and spleen volumes remained reduced throughout the 2-year extension study. Mean joint range of motion improved for the shoulder and remained stable in other joints. Both the parent-and child-assessed Child Health Assessment Questionnaire Disability Index Score demonstrated significant improvement. Infusion-related adverse events occurred in 53% of patients and peaked at Month 3 of treatment and declined thereafter. Neutralizing IgG antibodies were detected in 23% of patients and seemed to attenuate the improvement in pulmonary function. Conclusions: Weekly infusions of idursulfase result in sustained clinical improvement during 3 years of treatment. Genet Med 2011:13(2):95-101.

Background Olipudase alfa, a recombinant human acid sphingomyelinase (rhASM), is an investigational enzyme replacement therapy (ERT) for patients with ASM deficiency [ASMD; Niemann-Pick Disease (NPD) A and B]. This open-label phase 1b study assessed the safety and tolerability of olipudase alfa using within-patient dose escalation to gradually debulk accumulated sphingomyelin and mitigate the rapid production of metabolites, which can be toxic. Secondary objectives were pharmacokinetics, pharmacodynamics, and exploratory efficacy. Methods Five adults with nonneuronopathic ASMD (NPD B) received escalating doses (0.1 to 3.0 mg/kg) of olipudase alfa intravenously every 2 weeks for 26 weeks. Results All patients successfully reached 3.0 mg/kg without serious or severe adverse events. One patient repeated a dose (2.0 mg/kg) and another had a temporary dose reduction (1.0 to 0.6 mg/kg). Most adverse events (97%) were mild and all resolved without sequelae. The most common adverse events were headache, arthralgia, nausea and abdominal pain. Two patients experienced single acute phase reactions. No patient developed hypersensitivity or anti-olipudase alfa antibodies. The mean circulating half-life of olipudase alfa ranged from 20.9 to 23.4 hours across doses without accumulation. Ceramide, a sphingomyelin catabolite, rose transiently in plasma after each dose, but decreased over time. Reductions in sphingomyelin storage, spleen and liver volumes, and serum chitotriosidase activity, as well as improvements in infiltrative lung disease, lipid profiles, platelet counts, and quality of life assessments, were observed. Conclusions This study provides proof-of-concept for the safety and efficacy of within-patient dose escalation of olipudase alfa in patients with nonneuronopathic ASMD.

Eliglustat tartrate (Genz-112638), a specific inhibitor of glucosylceramide synthase, is under development as an oral substrate reduction therapy for Gaucher disease type 1 (GD1