A multicenter, open-label extension study of velaglucerase alfa in Japanese patients with Gaucher disease: Results after a cumulative treatment period of 24months

Enzyme replacement therapy (ERT) with exogenous glucocerebrosidase is indicated to treat symptomatic Gaucher disease (GD), a rare, inherited metabolic disorder. ERT with velaglucerase alfa, which is produced in a human cell line using gene activation technology, was studied in a 12-month phase III trial in Japanese patients with type 1 or 3 GD who were switched from imiglucerase ERT (n=6); the current, open-label, 12-month extension study was designed to assess longer-term safety and efficacy. Two adult and three pediatric patients (aged <18years) were enrolled into the extension study. Every-other-week intravenous infusions were administered for 63-78weeks at average doses between 51.5 and 60.7units/kg. Three non-serious adverse events were considered related to velaglucerase alfa treatment, but no patient discontinued from the study. Six serious but non-drug-related adverse events were reported. No patient tested positive for anti-velaglucerase alfa antibodies. Hemoglobin concentrations, platelet counts, and liver and spleen volumes (normalized to body weight) in these patients were generally stable over a cumulative 24-month period from the baseline of the parent trial. The data suggest that velaglucerase alfa was well tolerated and maintained clinical stability in Japanese GD patients over 2years after switching from imiglucerase. ClinicalTrials.gov identifier NCT01842841.