Iduronate-2-sulfatase Enzyme Replacement Therapy in Mucopolysaccharidosis II (MPS II)

MPS II is a rare, X-linked, lysosomal storage disorder caused by a deficiency in the enzyme iduronate-2-sulfatase. Because of this deficiency, glycosaminoglycans (GAG) accumulate in multiple tissues and organs, resulting in progressive cellular and organ system dysfunction. The purpose of this study is to determine if one year of therapy with iduronate-2-sulfatase enzyme replacement therapy, at a dose of 0.5mg/kg, weekly or every other week, is safe, and results in clinically meaningful improvement in multiple organ function, compared with a placebo group. Upon completion of the study, patients will be eligible to enroll in an open-label maintenance study.