Administration of IV Laronidase Post Bone Marrow Transplant in Hurler

The primary objective of this pilot study is to determine the feasibility of giving weekly
Laronidase for 2 years in patients with Hurler syndrome after allogeneic transplantation.
Specifically, i) the ability to enroll patients, ii) continued compliance throughout the
study with drug administration and testing, as well as iii) the relevance of various endpoint
determinations will be assessed. The findings of the pilot study will be used to assess
whether a subsequent larger study will be conducted.

Secondary Objectives: The secondary objectives of this study will focus on the toxicity
associated with weekly Laronidase in this patient population, and the evaluation of a variety
of testing and efficacy parameters that would be utilized to measure outcomes and determine
benefit in patients treated on a subsequent larger study.

Eligible patients will receive Laronidase as an infusion over several hours once a week at a
local site. The dosing of enzyme will be the standard doses recommended by Genzyme.

Inclusion Criteria:

- Mucopolysaccharidosis type IH (MPS I, Hurler syndrome) treated with a prior allogeneic
transplant >2 years previously

- Age <14 years old

- >10% engrafted based on recent testing (<4 months prior to enrollment)

- Willing to commit to traveling to the University of Minnesota every 6 months

- Written informed consent prior to the performance of any study related procedures

Exclusion Criteria:

- Previous administration of Laronidase enzyme > 3 months post transplantation

- Anticipated survival less than 2 years

- History of cardiac or pulmonary insufficiency, including an ejection fraction (EF) <
40% or those requiring continuous supplemental oxygen