A Multicenter, Open-label Extension Study of Velaglucerase Alfa Enzyme Replacement Therapy in Japanese Patients With Gaucher Disease

Gaucher disease is an inherited deficiency of the lysosomal enzyme glucocerebrosidase (GCB) that leads to progressive accumulation of glucocerebroside within macrophages and subsequent tissue and organ damage; typically of the liver, spleen, bone marrow, and brain. Gaucher disease has been designated in the list of Specified Rare and Intractable Diseases by Specified Disease Treatment Research Program of Ministry of Health, Labor and Welfare (MHLW) as one of "lysosomal storage diseases" since 2001. Gaucher disease is also designated in the Medical Aid Program for Specified Categories of Chronic Pediatric Diseases. The prevalence of mutations and the phenotype of patients with Gaucher disease in Japan differs from that in non-Japanese populations. Some patients with type 1 Gaucher disease in Japan have more severe and progressive disease compared to non-Japanese patients and the disease is characterized by an earlier onset of symptoms. Velaglucerase alfa, a highly-purified form of the naturally occurring enzyme glucocerebrosidase, has been developed as an enzyme replacement therapy for Gaucher disease for the symptoms (anemia, thrombocytopenia, hepatomegaly, splenomegaly, and bone manifestation). The primary objective of this study is to evaluate the long-term safety of every other week (EOW) dosing of velaglucerase alfa in Japanese patients with Gaucher disease who completed study HGT-GCB-087 and elected to continue treatment with velaglucerase alfa.