Stem Cell Transplant w/Laronidase for Hurler

Phase II Study of Combined Laronidase (AldurazymeTM) Enzyme Replacement Therapy (ERT) With Hematopoietic Stem Cell Transplantation (HSCT) for Hurler Syndrome (MPS IH)

The investigators hypothesize that weekly infusions of Laronidase ERT for 10-12 weeks prior to transplant and 8 weeks following transplant will result in a reduction of glycosaminoglycans (GAG) burden that is associated with decreased complications following transplant.

Subjects will receive laronidase once a week intravenously for 10-12 weeks prior to transplant and for approximately 8 weeks after transplant. Laronidase will be given by intravenous infusion (IV) through a catheter and from there to your child's body's cells and organs to break down the glycosaminoglycans (GAG) buildup.

Prior to starting ERT, subjects will have a complete physical examination, which includes a complete assessment of your child's airway and lungs. In addition to standard treatment evaluations and tests, which are done prior to hematopoietic stem cell transplant (HSCT), subjects will have the following tests: an additional teaspoon of blood for a baseline test for serum antibodies against laronidase, before and after the fourth dose of laronidase, the investigators will collect 2 teaspoons of blood for an alpha-L-iduronidase enzyme level; to watch for side effects to laronidase and the development of antibodies to laronidase, approximately 2 teaspoons of blood will be collected every 3 weeks while the subject is receiving laronidase ERT.

Inclusion Criteria:

• Patients with the diagnosis of mucopolysaccharidosis type IH (MPS I, Hurler syndrome) who are candidates for first hematopoietic stem cell transplant (HSCT) according to a University of Minnesota myeloablative HSCT protocol.

Exclusion Criteria:

• Not being considered for University of Minnesota myeloablative HSCT protocol.
• Previous administration of laronidase enzyme
• Second or subsequent HSCT.