###### ![](media/image1.png){width="1.0930555555555554in" height="0.9083333333333333in"} {#section .Style2}

**DEPARTMENT OF HEALTH & HUMAN SERVICES** Public Health Service

Food and Drug Administration

**Memorandum** Center for Biologics Evaluation and Research

> 1401 Rockville Pike

Rockville, MD 20852

Division of Clinical Trial Design and Analysis

HFM-576

> Date: December 13, 2002
>
> Subject: Advisory Committee Briefing Document
>
> BLA STN 125058/0
>
> Original Submission

**BioMarin Pharmaceuticals, Incorporated**

ALDURAZYME™

Laronidase

For the Treatment of Mucopolysaccharidosis I

Clinical Review

[]{#__RefHeading___Toc27725122 .anchor}Table of Contents

[Table of Contents 2](#__RefHeading___Toc27725122)

[Introduction 5](#__RefHeading___Toc27725123)

[Proposed indication and dose 5](#__RefHeading___Toc27725124)

[Biochemical and Clinical Background 5](#__RefHeading___Toc27725125)

[Product Background 8](#__RefHeading___Toc27725126)

[Regulatory History 9](#__RefHeading___Toc27725127)

[Pre-clinical studies 9](#__RefHeading___Toc27725128)

[Toxicology studies 9](#toxicology-studies)

[Pharmacodynamic studies 9](#pharmacodynamic-studies)

[Safety 10](#preclinical-safety)

[Overview of Clinical Studies 10](#__RefHeading___Toc27725132)

[Study BIO7500 12](#__RefHeading___Toc27725133)

[Overview 12](#overview)

[Protocol 12](#protocol)

[Design 12](#__RefHeading___Toc27725136)

[Objectives 13](#__RefHeading___Toc27725137)

[Eligibility Criteria 13](#__RefHeading___Toc27725138)

[Treatment assignment / randomization 13](#__RefHeading___Toc27725139)

[Product information and administration 13](#__RefHeading___Toc27725140)

[Evaluations 14](#__RefHeading___Toc27725141)

[Safety Monitoring 15](#__RefHeading___Toc27725142)

[Endpoints 15](#__RefHeading___Toc27725143)

[Statistical analysis 16](#__RefHeading___Toc27725144)

[Study Conduct 16](#study-conduct)

[Protocol Violations 16](#__RefHeading___Toc27725146)

[FDA site inspection findings 17](#__RefHeading___Toc27725147)

[Results 17](#results)

[Subject disposition 17](#__RefHeading___Toc27725149)

[Baseline characteristics 17](#__RefHeading___Toc27725150)

[Study drug exposure 18](#__RefHeading___Toc27725151)

[Primary endpoints 18](#__RefHeading___Toc27725152)

[Hepatomegaly 18](#hepatomegaly)

[Splenomegaly 18](#splenomegaly)

[Urinary Glycosaminoglycans 19](#urinary-glycosaminoglycans)

[Secondary endpoints 20](#__RefHeading___Toc27725156)

[Safety 23](#__RefHeading___Toc27725166)

[Summary 25](#summary)

[Study ALID-003 26](#__RefHeading___Toc27725172)

[Overview 26](#overview-1)

[Protocol 26](#protocol-1)

[Design 26](#__RefHeading___Toc27725175)

[Objectives 26](#__RefHeading___Toc27725176)

[Eligibility Criteria 26](#__RefHeading___Toc27725177)

[Treatment assignment / Randomization 27](#__RefHeading___Toc27725178)

[Product information and administration 27](#__RefHeading___Toc27725179)

[Evaluations 28](#__RefHeading___Toc27725180)

[Safety Monitoring 29](#__RefHeading___Toc27725181)

[Endpoints 29](#__RefHeading___Toc27725182)

[Statistical Analysis 30](#__RefHeading___Toc27725183)

[Study Conduct 31](#study-conduct-1)

[Database Integrity 32](#__RefHeading___Toc27725185)

[Protocol violations 32](#__RefHeading___Toc27725186)

[FDA site inspection findings 32](#__RefHeading___Toc27725187)

[Results 33](#results-1)

[Subject disposition 33](#__RefHeading___Toc27725189)

[Baseline characteristics 33](#__RefHeading___Toc27725190)

[Study drug exposure 34](#__RefHeading___Toc27725191)

[Primary endpoints 35](#__RefHeading___Toc27725192)

[Percent Predicted Forced Vital Capacity (% FVC)
35](#percent-predicted-forced-vital-capacity-fvc)

[Six minute walk distance (meters) 42](#six-minute-walk-distance-meters)

[Secondary endpoints 49](#__RefHeading___Toc27725195)

[Apnea / Hypopnea Index (AHI) of the sleep study
49](#apnea-hypopnea-index-ahi-of-the-sleep-study)

[Liver volume 51](#liver-volume)

[Disability Index from the CHAQ or HAQ
52](#disability-index-from-the-chaq-or-haq)

[Shoulder Flexion 52](#shoulder-flexion)

[Tertiary Endpoints 53](#__RefHeading___Toc27725200)

[Pharmacokinetic Studies 53](#__RefHeading___Toc27725203)

[Safety 55](#__RefHeading___Toc27725204)

[Summary 58](#summary-1)

[Study ALID-006 60](#__RefHeading___Toc27725211)

[Overview 60](#overview-2)

[Protocol 60](#protocol-2)

[Design 60](#__RefHeading___Toc27725214)

[Objectives 60](#__RefHeading___Toc27725215)

[Eligibility Criteria 60](#__RefHeading___Toc27725216)

[Treatment assignment / Randomization 61](#__RefHeading___Toc27725217)

[Product Information and Administration 61](#__RefHeading___Toc27725218)

[Evaluations 61](#__RefHeading___Toc27725219)

[Safety Monitoring 62](#__RefHeading___Toc27725220)

[Endpoints 62](#__RefHeading___Toc27725221)

[Statistical Analysis 62](#__RefHeading___Toc27725222)

[Study Conduct 63](#study-conduct-2)

[Database Integrity 63](#__RefHeading___Toc27725224)

[Protocol Violations 63](#__RefHeading___Toc27725225)

[FDA site inspection findings 63](#__RefHeading___Toc27725226)

[Results 63](#results-2)

[Subject disposition 63](#__RefHeading___Toc27725228)

[Study entry characteristics 64](#__RefHeading___Toc27725229)

[Study drug exposure 64](#__RefHeading___Toc27725230)

[Primary endpoints 64](#__RefHeading___Toc27725231)

[Percent Predicted Forced Vital Capacity (% FVC)
64](#percent-predicted-forced-vital-capacity-fvc-1)

[6 Minute Walk Distance 69](#minute-walk-distance)

[Secondary endpoints 75](#__RefHeading___Toc27725234)

[Tertiary endpoints 78](#__RefHeading___Toc27725239)

[Safety 79](#__RefHeading___Toc27725242)

[Summary 83](#study-006-summary)

[Summary of Efficacy 84](#__RefHeading___Toc27725250)

[Summary of Safety 85](#__RefHeading___Toc27725251)

[Conclusions and Recommendations 86](#__RefHeading___Toc27725252)

[Appendix A: Tertiary Endpoints of Study ALID-003
88](#__RefHeading___Toc27725253)

[Appendix B: Tertiary Endpoints of Study ALID-006
92](#__RefHeading___Toc27725254)

[]{#__RefHeading___Toc27725123 .anchor}Introduction

This document is the medical officer's review of the clinical data
submitted with the Biologics License Application (BLA) Submission
Tracking Number 125058. This application is for Laronidase (ALDURAZYME),
a recombinant enzyme product which is proposed for usage as enzyme
replacement therapy for patients with Mucopolysaccharidosis I.

[]{#__RefHeading___Toc27725124 .anchor}Proposed indication and dose

Biomarin proposes that Laronidase is indicated as long term enzyme
replacement therapy in patients with Mucopolysaccharidosis I (MPS I) to
treat the non- central nervous system manifestations of the disease. The
proposed dosage regimen of Laronidase is 100 U / kg (0.58 mg / kg)
administered once weekly intravenously.

Reviewer's comment: This disorder, as for all forms of lysosomal storage
diseases, has complex and multiple organ and tissue manifestations.
There are variable phenotypes and a broad spectrum of severity.
Evidence-based determination of a treatment effect on specific endpoints
should be required to support a claim of benefit for these endpoints. A
claim of general benefit in the management of the disease as a whole may
be inappropriate.

[]{#__RefHeading___Toc27725125 .anchor}Biochemical and Clinical
Background

Lysosomal storage disorders result from a genetic defect that causes
deficient production or function of one or more of the lysosomal
enzymes. The enzymatic deficiency results in an abnormal accumulation of
metabolites within a lysosome and ultimately disruption of the normal
cell function and cell death. Lysosomal storage disorders are usually
classified according to the nature of the macromolecule that is
abnormally catabolized and consequently accumulates within the lysosome.
Sphyngolipidoses (including gangliosidoses) are associated with the
accumulation of complex lipids, the basic structure of which is a
sphingosine, a long chain amino-alcohol. Oligosaccharidoses or
mucolipidoses are associated with the storage of complex glycoproteins.
Mucopolysaccharidosis are caused by deficiencies of enzymes needed to
degrade glycosaminoglycans (also known as mucopolysaccharides).
Glycosaminoglycans themselves are lysosomal degradation products derived
by proteolytic removal of the protein core of proteoglycans
(macromolecules occurring in the cell membrane and extracellular
matrix). Mucopolysaccharidosis I is the subject of this license
application, and will be described here briefly.

**Mucopolysaccharidosis I** (MPS I) is characterized biochemically by
the deficiency of the lysosomal enzyme α-L-iduronidase (IDU). This
enzyme cleaves the terminal iduronic acid residues of dermatan sulfate
and heparan sulfate (Figure 1).

Figure 1. Catabolism of glycosaminoglycans highlighting role of IDU

![](media/image2.wmf){width="5.993055555555555in"
height="7.440277777777778in"}

Source:
[www.genome.ad.jp/dbget-bin/get_pathway?org_name=hsa&mapno=00531](http://www.genome.ad.jp/dbget-bin/get_pathway?org_name=hsa&mapno=00531)
assessed on October 16, 2002

Experiments in cultured fibroblasts show that the enzyme is made in a
precursor form, cleaved intracellularly to a 628 amino acid protein and
incorporated with mannose 6-phosphate markers for targeting to
lysosomes. The gene encoding IDU is located in the short arm of
chromosome 4 (locus 4p16.3) and MPS I is inherited with autosomal
recessive transmission. Homozygosity or compound heterozygosity for the
W402X (stop codon) and Q70X mutations are the common causes of MPS I
with a severe form in affected Caucasian individuals. Japanese patients
with MPS-I have other predominant IDU gene mutations.

Historically, MPS I patients have been broadly categorized into three
clinical syndromes: Hurler, Hurler-Scheie, and Scheie, representing
severe, intermediate, and mild clinical phenotypes, respectively. These
classifications are arbitrary categorizations of points on a continuous
spectrum of patient phenotypes. Biochemically, patients with the milder
disease form retain trace residual amounts of IDU that are sufficient to
ameliorate the phenotype to varying degrees. However there is
considerable heterogeneity in the severity and symptoms within each
phenotype and substantial overlap of the three syndromes. The true
incidence of MPS I is unknown, with estimates in the range of 1/76,000
for MPSIH, 1/280,000 for MPS IH-S, and less than 1 in 840,000 live
births for MPS IS in Northern Ireland. Semi quantitative analysis of
spot urinary glycosaminoglycans can be used for screening, but is
subject to both false negative and false positive results. Definitive
diagnosis is established by lysosomal enzymes assays in leukocytes,
cultured skin fibroblasts or serum. Pre-natal diagnosis is established
by IDU assays in cultured cells from amniotic fluid or chorionic villus
biopsies. Carrier testing is currently performed with analysis of enzyme
activity in family members, but may be superseded by molecular analysis
of specific family mutations in the enzyme gene.

Hurler syndrome (MPS IH) is a progressive disorder that affects multiple
organs and tissues and leads to death during childhood. The symptoms of
MPS IH present between 6 months and 2 years of age. They include
inguinal or umbilical hernias, hepatosplenomegaly, coarse facies,
deafness, recurrent ear and sinus infections, macroglossia, noisy
breathing, obstructive airway disease and sleep apnea, communicating
hydrocephalus with increased intracranial pressure, prominent forehead,
developmental delay, skeletal deformities (dysostosis multiplex),
corneal clouding, joint stiffness, acute cardiomyopathy associated with
endocardial fibroelastosis, valvular heart disease and pulmonary
hypertension. The most frequent causes of death are related to
obstructive airway disease, respiratory infections and cardiac
complications.

Symptoms of Hurler-Scheie Syndrome (MPS IH-S) include dysostosis
multiplex, corneal clouding, joint stiffness, short stature, deafness,
and obstructive airway disease with little or no intellectual
dysfunction. The onset of these symptoms is observed between ages 3 and
8 years of age, and death usually occurs in the second or third decade
of life, usually from the same complications described in the Hurler
patients.

Patients with Scheie Syndrome (MPS IS) have variable amounts of joint
stiffness, aortic valve disease, mild hepatosplenomegaly, and corneal
clouding, usually without neurologic involvement. Symptoms start in
children older than 5 years and the diagnosis is usually made between 10
and 20 years of age. Patients achieve normal stature and normal
lifespan.

Current management of patients with MPS I is restricted to supportive
care and treatment of specific complications. Ventriculoperitoneal
shunting in moderate to severe hydrocephalus, ventilating tubes and
hearing aids, range of motion exercises, tracheostomy and high pressure
nasal continuous positive airway pressure, mitral or aortic valve
replacement can improve symptoms.

A treatment that can replace the defective enzyme by supplying either
cells capable of normal IDU secretion or functional IDU can potentially
improve the clinical manifestations of MPS I. Cell culture and animal
model experiments have demonstrated feasibility and raised optimism.
Despite numerous trials using different enzyme sources, the only
significant advance has been transplantation of allogeneic bone marrow
in patients with MPS IH, particularly if instituted before the age of 2
years. With stable bone marrow engraftment the biochemical and somatic
features revert, and long-term survival is possible. Neuropsychological
function and some skeletal abnormalities are not reversed in patients
that undergo bone marrow transplantation after age 2. However,
limitations in the appropriate donor pool, and the high risks of
significant morbidity and mortality make this therapeutic option
restricted to a few affected individuals.

With the cloning of complementary DNA for IDU, large scale production of
the recombinant human α - L -- IDU became possible, with the mannose 6
phosphate sites necessary for targeting lysosomes.

[]{#__RefHeading___Toc27725126 .anchor}

Product Background

Recombinant human α -L-iduronidase (rhIDU) is a 628 amino acid lysosomal
hydrolase. The enzyme is a single polypeptide chain of molecular mass
70.1 kilodaltons (from translated cDNA sequence). rhIDU contains six
N-linked glycosylation sites, two of which carry the bis
mannose-6-phosphate oligomannose7 7 oligosaccharide that binds the
target cell surface receptor. The apparent molecular mass of full-length
rhIDU is approximately 83 kilodaltons, suggesting that posttranslational
modifications of rhIDU contribute approximately 13 kilodaltons to the
molecular mass.

\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\--
. The \-\-\-\-\-\-\-\-\-\-\-\-- formulated drug product is supplied as a
sterile solution at a concentration of 0.58 mg/mL (100 U/mL) in a sodium
chloride and sodium phosphate buffer. Each vial of drug product contains
2.90 mg of Aldurazyme™ and is intended for single use.

The product used in the pre-clinical studies and the Phase 1 clinical
study was originally defined with an activity of 125,000 U/mL and a
protein concentration of 0.5 mg/mL. These characteristics of laronidase
were subsequently redefined (due to changes in assay procedures) as 100
U /mL activity and 0.58 mg/mL protein concentration. These redefinitions
do not represent any changes in actual enzyme activity or concentration,
rather reflecting changes in assay methodology. However, terminology
used in the Phase 1 study and in preclinical study reports are based
upon the prior assay process.

[]{#__RefHeading___Toc27725127 .anchor}Regulatory History

Development of laronidase was conducted under IND 7334, initially
submitted September 19, 1997 proposing a Phase 1 clinical study.
Subsequently, a single Phase 3 study was conducted.

[]{#__RefHeading___Toc27725128 .anchor}Pre-clinical studies

*Reviewer's comment: It is important to note that the assay for
α-L--iduronidase activity was changed during the drug development to
make it more reproducible and robust. A change in the definition of
activity unit to be more conventional occurred as a consequence. The
dose used in the Phase 1 study was reported as 125,000 U, which was
determined to be equivalent to 100 U under the revised activity
definition. The method for determination of protein concentration was
also changed, resulting in a small apparent mass increase, such that the
0.5 mg / ml formulation of rhIDU now measured 0.58 mg / ml in the new
assay.*

*Dosing in all the pharmacodynamic studies was reported on an enzymatic
activity basis (U / kg) using the old activity unit and protein assay.
Dosing in the toxicity studies was reported only on a weight basis using
the older protein assay. Most of the pre-clinical study reports present
the dose used in a mg / kg basis, except for the pharmacodynamic
studies, which also present data in the original activity units for
comparison to the published literature.*

###### Toxicology studies {#toxicology-studies .Style2}

Placebo and dose-controlled acute toxicity studies using single doses of
laronidase were conducted in rats and dogs with a dose range of 0.29 to
5.8 mg kg in rats and 0.116 to 11.6 mg/kg in dogs. No treatment related
toxicities were found, although dogs had low incidence of emesis and
mucoid liquid stools following treatment with laronidase, unrelated to
dose. Female rats developed small foci of hepatocellular necrosis of
unclear relationship to the treatment and unclear significance.

An intravenous laronidase study in cynomolgus monkeys showed a slight
increase in lymphocytes and eosinophils when the highest dose (16.6
mg/kg) was infused weekly for 26 weeks.

###### Pharmacodynamic studies {#pharmacodynamic-studies .Style2}

In vitro studies were carried out to explore the uptake of laronidase by
MPS I patient fibroblasts, its effect on GAG storage and its cell
half-life. These studies demonstrated effective laronidase endocytosis
by the fibroblasts via a mannose-6-phosphate dependent receptor with a
half-maximal uptake at approximately 0.7 nM enzyme. Laronidase reduced
GAG storage in MPS I patient fibroblasts with half-maximal reduction at
approximately 0.7 pM. The half-life of the enzyme in the fibroblasts was
estimated at 5 days.

*Reviewer's comment: The sponsor claims this result supports a once
weekly dosing regimen, but no in-vivo studies were performed to examine
the tissue half-life of the enzyme.*

Subsequent studies in the canine model using laronidase at 125,000
versus 500,000 U/kg/week (0.5 or 2.0 mg/kg/week) showed superiority of
9-hour weekly infusions over continuous infusions in raising tissue
enzyme levels and decreasing tissue GAG accumulation. More importantly,
this study also demonstrated that at the 2.0 mg/kg/week dose, the 9-hour
infusion was more effective than continuous infusion at lowering GAG
levels in cornea, kidney cortex, liver, myocardium, pancreas, synovium,
cerebral cortex, and medulla. There were no significant differences in
GAG accumulation within denser connective tissues (i.e. ligaments,
cartilage, cornea, atrioventricular valve leaflets).

###### Preclinical Safety {#preclinical-safety .Style2}

Infusion related anaphylactoid reactions were observed in dogs and cats
and managed by stopping the infusion, intravenous fluid administration
and, if necessary, oxygen supplementation. The most likely cause of
these reactions is IgG-mediated complement activation. Anti-histamines
treatment prior to the infusions was effective in eliminating or
decreasing these reactions. Lowering the infusion rate and the addition
of canine serum albumin also mitigated these reactions in long term
laronidase administration. BioMarin notes that the clinical grade
product is more pure than the one used in the pre-clinical studies, and
polysorbate 80 added as a detergent in the clinical grade product can
potentially decrease microaggregation. Anaphylactoid reactions were not
seen in monkeys or dogs treated with the clinical grade product, even
without pre-treatment with antihistamines.

[]{#__RefHeading___Toc27725132 .anchor}Overview of Clinical Studies

This application contains data from a total of 59 patients with various
forms of MPS I. The initial open label study of laronidase has been
extended as a single arm, uncontrolled trial. Study ALID-003 enrolled 45
subjects into the single randomized, placebo controlled, double blind
trial reported with this application. At the end of the study all
subjects were offered participation in an open label single arm
laronidase protocol. Subjects previously randomized to placebo were
converted to laronidase treatment.

There is also a small ongoing Open Label Study that provides treatment
for patients with late-stage MPS I who are seriously ill and do not meet
the selection criteria for participation in ongoing clinical studies. As
of 29 April 2002, 4 patients had received laronidase treatment in this
program.

The sponsor has conducted 3 clinical studies during the clinical
development of laronidase (Table 1)

Table 1. Clinical Studies Included in this Submission

+--------------+------------------+-----------+----------+--------+---+
| **Protocol** | **Study Design** | **C       | **L      | **Du   | * |
|              |                  | ompletion | ocation/ | ration | * |
|              |                  | Status /  | Number   | of     | n |
|              |                  | Study     | of       | tre    | * |
|              |                  | Dates**   | C        | atment | * |
|              |                  |           | enters** | (we    |   |
|              |                  |           |          | eks)** |   |
+--------------+------------------+-----------+----------+--------+---+
| **ALID-003** | Phase 3 Double   | Completed | USA:2    | 26     | 4 |
|              | Blind, Placebo   |           |          |        | 5 |
|              | Controlled       | 12/28/00  | Canada:  |        |   |
|              | Randomized       | to 9/6/01 | 1        |        |   |
|              |                  |           |          |        |   |
|              |                  |           | UK: 1    |        |   |
|              |                  |           |          |        |   |
|              |                  |           | Germany: |        |   |
|              |                  |           | 1        |        |   |
+--------------+------------------+-----------+----------+--------+---+
| **ALID-006** | Phase 3 Open     | Ongoing   | USA: 13  | 24     | 4 |
|              | Label ,          |           |          |        | 5 |
|              | non-randomized   |           | Canada:  |        |   |
|              | Extension        |           | 2        |        |   |
|              |                  |           |          |        |   |
|              |                  |           | UK: 1    |        |   |
|              |                  |           |          |        |   |
|              |                  |           | Germany: |        |   |
|              |                  |           | 2        |        |   |
+--------------+------------------+-----------+----------+--------+---+
| **BIO7500**  | Phase 1 / 2 Open | Ongoing   | USA: 13  | 171    | 1 |
|              | Label,           |           |          | (s     | 0 |
|              | non-randomized   | Started   |          | afety) |   |
|              |                  | 11/28/97  |          |        |   |
+--------------+------------------+-----------+----------+--------+---+
| **Special    | Uncontrolled     | Ongoing   | Au       | 35     | 3 |
| Access &     | administration   |           | stralia: |        |   |
| ALID-007**   |                  |           | 3        |        |   |
+--------------+------------------+-----------+----------+--------+---+
|              | Single patient   | Completed | USA: 1   | 28     | 1 |
|              |                  | (subject  |          |        |   |
|              |                  | died)     |          |        |   |
+--------------+------------------+-----------+----------+--------+---+

A multicenter observational study (ALID-004) was also conducted in 2000
to collect normative data in patients with MPS I. The single session
survey included 5 centers in the USA and Europe and enrolled 45
patients. The objective was to determine median values for the six
minute walk distance test (6MWD) and the forced vital capacity (FVC) in
patients with MPS I intended to participate in the Phase 3 clinical
trial. Information from this study was used to partly guide design of
Study ALID-003. A notable finding was the higher than expected distances
on the six minute walk test. This relatively mild degree of impairment
might have suggested that there would be difficulty in demonstrating a
clinically meaningful difference in a randomized study.

[]{#__RefHeading___Toc27725133 .anchor}Study BIO7500

"Phase 1 / 2, Open-Label Study of Recombinant Human α - L -- Iduronidase
as Enzyme Replacement Treatment for Mucopolysaccharidosis I (MPS I)".

###### Overview {#overview .Style2}

This study was conducted under IND 7334 according to Protocol
BIO7500-001. The study started on November 28, 1997 and is still
ongoing.

The submitted study report contains safety and clinical outcome data
derived from a 152 week period. The original protocol submitted proposed
a 26 week study and was subsequently modified to extend the treatment
duration. A change in product manufacture method and formulation
occurred during the study. Crossover comparisons of pharmacokinetic and
pharmacodynamic parameters were done.

The reported results demonstrate that the newer product had a comparable
safety profile to the older product in the seven subjects that
participated in the crossover study. An apparent increase in plasma
enzyme activity 20 minutes after completion of infusion was observed
with newer as compared to the older product.

###### Protocol {#protocol .Style2}

**Title**: "Phase 1 / 2, Open-Label Study of Recombinant Human α - L --
Iduronidase as Enzyme Replacement Treatment for Mucopolysaccharidosis I
(MPS I)". Protocol BIO7500-001.

The study was initiated on November 28, 1997 and the reporting period
included in the corresponding study report included in this submission
ended on March 30, 2001. Six protocol amendments occurred after
initiation of the study. These served largely to clarify certain study
criteria or procedures, or to extend the study duration, and are
incorporated in the following description.

[]{#__RefHeading___Toc27725136 .anchor}Design

Open label non-randomized, single dose, multicenter, phase 1 study in 10
subjects with MPS I. Effect of laronidase treatment was compared to
pre-treatment levels. The study drug was to be administered
intravenously on a weekly basis initially for a period of 26 weeks.
Subsequent amendments to the protocol extended the study period to 152
weeks.

*Reviewer's comment: the sponsor classified this design as "patients
serving as their own control" but this is in reality an uncontrolled
study.*

*Reviewer's comment: this study is classified as a multicenter study,
but the design is such that all eligible subjects receive the first 6
weeks of product administration at one site (Harbor-UCLA Clinical
Research Center) and would have to return to this site for efficacy
assessments at 12, 26, 52 and 104 weeks of treatment.*

[]{#__RefHeading___Toc27725137 .anchor}Objectives

-   Assess the safety of repeated infusions of laronidase

-   Assess the effect of repeated infusions of laronidase in the
    reduction of lysosomal storage as assessed by liver and spleen size
    and urinary GAG excretion and in clinical conditions caused by MPS
    I, including joint disease, cardiac disease, sleep apnea/airway
    obstruction, and eye disease

[]{#__RefHeading___Toc27725138 .anchor}Eligibility Criteria

**Inclusion criteria:**

-   Male and female patients with a clinical and enzymatic diagnosis of
    MPS I, as confirmed by clinical and enzymatic assessments by the
    Study Investigators.

-   Patients at least 5 years of age.

-   Patients with significant physical disease indicative of MPS I,
    including enlarged liver or spleen size (≥ 1.5 times normal for age)
    and elevated urinary GAG (≥ 5 times normal for age).

**Exclusion Criteria:**

-   Patients who were critically ill. Critical health conditions
    included congestive heart failure, serious respiratory compromise
    with chronic hypoxia or pulmonary hypertension, serious spinal cord
    compression with evidence of substantial neurologic compromise, or
    any other conditions which could have prevented the child from
    cooperating and tolerating the experimental protocol or might be
    expected to lead to death or incapacitation within the study period.

-   Patients who had previously undergone bone marrow transplant.

-   Patients who received an investigational drug or procedure within 30
    days of study enrollment.

[]{#__RefHeading___Toc27725139 .anchor}Treatment assignment /
randomization

In this non-randomized study all subjects were assigned to active
treatment.

[]{#__RefHeading___Toc27725140 .anchor}Product information and
administration

Laronidase was diluted in normal saline with 0.1% (1.0 mg/mL) human
serum albumin. The total laronidase dose was 125,000 U/kg (100 U/kg by
redefined units), infused over a 3-4 hour period. Intravenous
diphenidramine pre-medication was given 10-30 minutes prior to enzyme
infusion. During the first hour, the enzyme was infused at a rate of 50
U/kg/min equivalent to 3,000 U/kg/hr. During the second and third hours,
the rest of the dose was administered at a maximum rate of 61,000
U/kg/hr.

[]{#__RefHeading___Toc27725141 .anchor}Evaluations

> (except as noted, at baseline, weeks 6, 12, 26, 52, 104)

a.  [Liver and spleen volume]{.underline} were assessed by MRI. Organ
    density assumed 1g/ml to enable calculation of organ weight as a
    percentage of body weight. An unblinded radiologist evaluated the
    MRI in real time. At study end a second radiologist blinded to
    subject identity and MRI timepoint analyzed organ volumes in a
    randomized fashion. These data were compared to healthy children and
    adolescents liver and spleen weights in proportion to the average
    weight for their age. Liver and spleen volume data is reported
    through week 104 in the unblinded extension study.

b.  [Urinary GAG]{.underline} was collected at pre-treatment and weekly
    for the first 6 weeks, and at decreasing frequency thereafter. All
    determinations were made at Harbor-UCLA by a validated method using
    Alcyan blue dye and quantification by spectrophotometer. The values
    were corrected by urine creatinine concentration and expressed as
    micrograms of GAG per mg of creatinine.

c.  [Joint range of motion (ROM)]{.underline} of shoulder, knee and
    elbow. Measurements obtained by a single physical therapist using a
    goniometer. 5 independent measurements for each joint and for each
    visit were obtained and averaged.

d.  [Cardiac function]{.underline} was assessed in a prospectively
    defined but unvalidated "cardiac scoring system" which is a
    composite score of EKG (weight 3), echocardiogram (weight 5),
    history (weight 4), physical examination (weight 4), and
    radiological findings (weight 4). The subject was also assessed
    according to the New York Heart Association functional
    classification.

e.  [Airway obstruction]{.underline} was assessed by a variety of
    parameters measured during polysomnography to investigate the
    frequency of apnea (cessation of airflow for 10 or more seconds),
    hypopnea (50% decrease in airflow per breath accompanied by arousal
    or desaturation), as well as minutes of hypoxia (oxygen saturation
    below 90%). Sleep studies were performed at pre-treatment, week 26,
    and if previously abnormal, at weeks 52 and 104. MRI assessments of
    the tongue and measurement of the airway index (ratio of
    mid-sagittal anterior-posterior width of the pharyngeal and tracheal
    airway to total width of the pharynx) were performed by an unblinded
    radiologist at pre-treatment and at weeks 6, 12, 26, 52 and 104.

f.  [Eye disease]{.underline} was assessed by a combination of visual
    acuity testing, complete ophthalmologic exam, intraocular pressure
    measurements, corneal photographs.

g.  [Central nervous system abnormalities]{.underline} were assessed by
    brain and cervical cord MRI, by lumbar puncture if there were no
    contraindications for the procedure, and by a pediatric neurologist
    examination. In addition the Wechsler Intelligence Scale was
    administered

h.  [Genetic skeletal surveys]{.underline} .

i.  [Height and weight]{.underline} were assessed from health records
    obtained from the 2 years prior to study to establish baseline
    growth rates, and every 4 weeks to week 52, and every 12 weeks to
    week 152 during treatment with rhIDU in pre-pubertal subjects (age 5
    to 12). Only those assessments performed at Harbor-UCLA were used in
    the analysis of the results.

j.  [Clinical Laboratory Safety assessments]{.underline} were performed
    periodically during the study. 24 hour creatinine clearance was
    performed at pre-treatment and weeks 12, 26, 52 and 104. Complement
    testing (CH50, C3 and C4) was done pre- and post-infusion, at
    pre-treatment and weeks 4, 6, 12, 26, 52, and 104. ELISA assessments
    for IgG serum antibodies against rhIDU with Western blot specificity
    confirmation were performed at pre-treatment and weeks 1, every
    other week to week 26, every 4 weeks to week 52, and every 12 weeks
    to week 152.

k.  [Enzyme activity]{.underline} was assessed in buccal brushings.
    Enzyme activity was also assessed in leukocytes.

l.  [Pharmacokinetic studies]{.underline} were performed at
    pre-treatment, and weeks 1, 2, 12 and 26. Pharmacokinetic studies
    were also performed on Week 6 for subjects 001 and 002, in addition
    to the other timepoints.

[]{#__RefHeading___Toc27725142 .anchor}

Safety Monitoring

A study monitor designated by BioMarin would monitor both safety and
study conduct at the study sites.

[]{#__RefHeading___Toc27725143 .anchor}

Endpoints

Primary endpoints: The primary endpoints cited in the original protocol
were:

1.  Proportion of subjects with 20 % reduction of the
    [excess]{.underline} size of either liver or spleen or both. In
    order to calculate the excess organ size the sponsor proposed to
    subtract the normal organ size, which in the original protocol was
    estimated as 2.5 % of body weight for the liver and 0.2 % of body
    weight for the spleen.

*Reviewer's comment: This endpoint has changed substantially in
subsequent amendments of the protocol. Amendment 1 of 3/3/98 revised the
definition of a significant reduction in organomegaly to a 20 %
reduction in the [total]{.underline} size of either the liver or the
spleen or both. The 20% criterion was selected by reference to
experience in Gaucher's disease. However, it is unclear how to
extrapolate the clinical meaning of hepatomegaly in one disorder to a
different disorder.*

2.  Percentage reduction in urinary GAG excretion as calculated by
    taking the average of the pretreatment samples compared with the
    average of samples from the last 6 weeks of therapy.

*Reviewer's comment: The definition of endpoint for analysis was very
vague in the original protocol. Amendment 2 (9/13/98) revised the
definition in the statistical analytical plan as "the four pre-treatment
values will be averaged and compared with the last six specimens taken
through week 26". As the study duration was extended, the timepoint for
endpoint comparison has been modified.*

*A general comment related to the analysis of "efficacy" endpoints is
that this study is uncontrolled, and variations in these endpoints would
demonstrate, at best, bioactivity to guide more definitive studies.*

Secondary endpoints:

1.  Cardiac ejection fraction, valvular regurgitation, pulmonary
    hypertension as assessed by the cardiac scoring system, and NYHA
    classification

2.  Corneal clouding, and visual acuity

3.  Joint stiffness / range of motion, based on goniometer, subjective
    reports of stiffness or pain, as well as video examinations of
    standard motions.

[]{#__RefHeading___Toc27725144 .anchor}Statistical analysis

The revised analytic plan provided for specific analysis procedures
which were not detailed in the original protocol.

*Reviewer's comments: In this uncontrolled study, pre- and
post-treatment comparisons are not meaningful in support of laronidase
efficacy.*

###### Study Conduct {#study-conduct .Style2}

Study Conduct was monitored by 2 contract research organizations (CRO's)
during the study period: from 11/28/97 until 6/12/2000 Inveresk Research
was charged with study monitoring and from 6/12/00 until the end of the
study period Abt Associates Clinical Trials monitored study conduct.

This study report includes data collected through March 30, 2001. As of
this date, the first patient enrolled had completed Week 171 and the
last patient enrolled had completed Week 152.

[]{#__RefHeading___Toc27725146 .anchor}Protocol Violations

The most common deviations involved variations from protocol-specified
collection times for safety and efficacy assessments, particularly
laboratory evaluations (urinalysis, urinalysis with microscopy, CBC, and
blood chemistries) and urinary GAG measurements. Most variations
resulted from missed study visits. Together the 10 subjects missed a
mean of 19.8 infusions due to frequent unavailability of study drug from
December 1998 through December 1999.

*Reviewer's comment: The sponsor does not explain the unavailability of
laronidase during the study period. The sponsor states that 66% of
missed infusions are due to laronidase unavailability, but this figure
is inconsistent with the Appendix that lists protocol violations.*

[]{#__RefHeading___Toc27725147 .anchor}FDA site inspection findings

No site inspections have been performed for this study.

###### Results {#results .Style2}

[]{#__RefHeading___Toc27725149 .anchor}Subject disposition

Ten subjects were enrolled into this study. The first subject signed the
consent form and was enrolled on November 28, 1997, the first study dose
was given on December 19, 1997, and the last subject completed the
152-week timepoint on March 29, 2001. All 10 subjects successfully
completed the first 52 weeks of the study, and 8 subjects were active at
Week 152. Subject 008 died between Weeks 103 and Week 104 of a viral
illness. Subject 002 died 19 days after the patient's last study drug
infusion at Week 137 of complications following spinal fusion surgery
for worsening of scoliosis.

[]{#__RefHeading___Toc27725150 .anchor}Baseline characteristics

Table 2 shows the demographic and relevant baseline characteristics of
the subjects enrolled in this study.

Table 2. Demographic and baseline characteristics

  ------------- --------- ----------- ----------- ------------ ---------- ------------
  **Subject**   **Age     **Height    **Weight    **Gender**   **Race**   **Clinical
                (yrs)**   (cm)**      (kg)**                              Status**

  **001**       17        132.5       38.1        M            White      MPS IH-S

  **002**       10        121         22.6        F            White      MPS IH-S

  **003**       9         122.5       27          M            White      MPS IH-S

  **004**       8         125         34.6        M            White      MPS IH-S

  **005**       12        127         24.4        M            White      MPS IH-S

  **006**       22        152.7       64.5        M            White      MPS IH-S

  **007**       17        160         57.2        F            White      MPS IS

  **008**       5         87          14.8        F            White      MPS IH

  **009**       9         118.5       24.2        F            White      MPS IH-S

  **010**       14        160         54.6        M            White      MPS IH-S
  ------------- --------- ----------- ----------- ------------ ---------- ------------

There were 6 pre-pubertal subjects in the study. These subjects covered
a broad spectrum of clinical presentation. The Principal Investigator /
Medical Monitor used a protocol classification of MPS I phenotypes to
describe the subjects disorder severity at the time of enrollment. Under
this classification one subject had mild disease (MPS IS, Scheie), 8
subjects had moderate disease (MPS IH-S, Hurler-Scheie) and one subject
had severe disease (MPS IH, Hurler). All subjects had in common the wide
spectrum of MPS I impairments, with unknown and variable intensity in
each affected organ, tissue or functional system. Most of the
concomitant medications used by these subjects at the time of entry were
analgesics or anti-inflammatory agents for relief of headaches or other
pains.

*Reviewer's comment: It is important to note that the phenotype
classification is based on a subjective impression of the overall degree
of organ or tissue impairment seen at a specific age range.*

[]{#__RefHeading___Toc27725151 .anchor}Study drug exposure

Ten subjects participated in this uncontrolled, open label study and
have received by the time of the study report weekly intravenous
infusions of rhIDU for an average 151 weeks (range 103 -- 171).

The mean (± SD) number of administered infusions per subject was 115.0
(± 17.5, range 82 to 135). As mentioned under Protocol Violations, the
majority of missed infusions were due to unavailability of the study
drug. Most of the other infusions were missed because of patient
illnesses or surgeries, parents' illnesses, logistical problems in
getting to the clinic, vacations, or decisions on the part of the
subject or parents to receive infusions less frequently than once a
week.

[]{#__RefHeading___Toc27725152 .anchor}Primary endpoints

#### **[Hepatomegaly]{.underline}**

######## Results of the blinded review of liver volumes are reported in Table 3. Due to the wide variation in liver volumes at baseline, these results were normalized as percent reduction from baseline for each subject and averaged.

Table 3. Mean normalized liver volume as a percentage of pre-treatment

  ------------------- ------------- ---------- -------------------------------
  **Time**            **Mean**      **SD**     **\# Subjects with ≥ 20 %
                                               decrease**

  **Pre-treatment**   100           0          N/A

  **Week 6**          79.9          6.5        5

  **Week 12**         78.2          6.1        6

  **Week 26**         76.6          10.2       8

  **Week 52**         75.0          9.2        7
  ------------------- ------------- ---------- -------------------------------

The 3 subjects that did not achieve the stated endpoint of 20 %
reduction had liver volumes in the normal range for their ages by week
52, and achieved the 20% or greater reduction in liver volume in the
unblinded readings at week 104.

#### **[Splenomegaly]{.underline}**

Results of MRI blinded review of the spleen volumes paralleled those
obtained for liver volumes. 7 of the 10 subjects demonstrated a ≥ 20%
reduction at week 6. Subject 009 developed clarithromycin-induced
hepatitis just prior to the Week 26 imaging timepoint, with a sharp
increase in liver and particularly spleen size to twice her baseline
volume. As her serum liver enzymes normalized by week 46, both the liver
and spleen volumes returned to normal.

In conclusion, using blinded MRI readings, 7 of 10 subjects had a
greater than 20% reduction in liver volumes at Week 52, and 5 of the 10
subjects had a 20% reduction in spleen volume at Weeks 26 and 52. Using
unblinded MRI readings, 9 of the 10 subjects had normalized liver size
by week 52 (8 / 9 by week 104) and 2 of the ten subjects had normalized
spleen volumes by weeks 52 (1 / 9 by week 104).

BioMarin believes
(\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\--)
that the reduction in liver and spleen sizes caused improvements in
comfort and edurance and the ability to eat and breathe.

*Reviewer's comment: It is important to note that even though the
reduction in liver and spleen volumes was clearly demonstrated, its
impact on general well being of the subjects may have been overstated by
other factors, including the fact that this is an open label,
uncontrolled study.*

#### **[Urinary Glycosaminoglycans]{.underline}**

All subjects had elevated urinary GAG levels prior to treatment that
were generally proportional to the severity of disease in this limited
sample of MPS I subjects. For example, the most severely affected
subject (008) had urinary GAG exceeding 500 µg GAG/mg creatinine,
whereas the subjects with the mildest disease (003 and 007) had levels
of 63.25--112.8 µg GAG/mg creatinine. **Table 4** shows the mean
normalized urinary GAG level reported as percentage of baseline from
pre-treatment to week 152. By week 152 mean GAG levels were within the
normal range.

Table 4. Mean normalized urinary GAG as a percentage of pre-treatment

  ------------------- ------------ --------- ------- ----------------------------
  **Time**            **Mean**     **SD**    **n**   **\# Subjects with ≥ 50 %
                                                     decrease**

  **Pre-treatment**   100          0         10      N/A

  **Week 6**          31.8         5.9       10      10

  **Week 12**         33.6         9.0       10      10

  **Week 26**         31.3         8.2       10      10

  **Week 52**         37.2         11.3      10      8

  **Week 104**        26.4         6.7       9\*     9

  **Week 152**        21.5         9.3       7\*\*   7
  ------------------- ------------ --------- ------- ----------------------------

\* Subject 008 died before week 104

\*\* Subject 002 died before week 152

For comparison, mean (± SD) urinary GAG in 68 healthy subjects is as
follows: 32.4 ± 6.9 μg GAG/ mg creatinine for ages 3 -- 12 (n=42), 14.9
± 3.4 μg GAG/mg creatinine for ages 13-18 (n=12), and 8.5 ± 1.8 μg
GAG/mg creatinine for ages 19-52.

*Reviewer's comment: This study provides indication of laronidase
activity through the substantial but incomplete reduction in urinary GAG
levels. The sites of enzyme action and the extent of tissue and organ
function recovery cannot be inferred from these data. Similarly, the
clinical significance of this finding remains unclear.*

[]{#__RefHeading___Toc27725156 .anchor}Secondary endpoints

#### **[Joint ROM]{.underline}**

Subjects were evaluated for shoulder flexion and extension, knee flexion
and extension, and elbow extension. Results were analyzed for changes in
ROM (the angle of a limb relative to the body at maximal flexion or
extension) and changes in degrees of restriction of ROM (mean degrees of
movement in an age-adjusted normal population minus the degrees of
movement in the MPS I subjects).

By Week 26, the majority of subjects showed some improvement in ROM in
one or more joints, although inter-subject variability was large. The
movements that showed the most improvements at Week 52 were shoulder
flexion, knee extension, and elbow extension (Table 5)

Table 5. Mean (± SD) Joint ROM and changes from pre-treatment

  ------------------- ------------------- ----------- ------------------------
  **Joint**           **Time**            **Mean ± SD **Mean (± SD) change
                                          (angle)**   from pre-treatment**

  **R Shoulder        **Pre-treatment**   100.6 ±     28.1 ± 21.5
  flexion**                               17.5        

                      **Week 52**         128.7 ±     
                                          16.2        

  **L Shoulder        **Pre-treatment**   101.2 ±     26.1 ± 26.8
  flexion**                               18.5        

                      **Week 52**         127.4 ±     
                                          17.6        

  **R Shoulder        **Pre-treatment**   32.1 ± 14.0 5.1 ± 19.1
  extension**                                         

                      **Week 52**         37.2 ± 7.1  

  **L Shoulder        **Pre-treatment**   26.8 ± 6.9  7.6 ± 12.8
  extension**                                         

                      **Week 52**         34.4 ± 7.5  

  **R Elbow           **Pre-treatment**   156.7 ±     7.0 ± 6.3
  extension**                             13.4        

                      **Week 52**         163.7 ±     
                                          13.6        

  **L Elbow           **Pre-treatment**   156.1 ±     7.1 ± 9.0
  extension**                             19.1        

                      **Week 52**         163.2 ±     
                                          16.7        

  **R Knee flexion**  **Pre-treatment**   126.6 ±     4.7 ± 5.0
                                          14.1        

                      **Week 52**         131.3 ±     
                                          14.4        

  **L Knee flexion**  **Pre-treatment**   126.6 ±     3.6 ± 8.8
                                          19.7        

                      **Week 52**         130.1 ±     
                                          13.7        

  **R Knee            **Pre-treatment**   172.0 ±     3.5 ± 10.4
  extension**                             11.0        

                      **Week 52**         175.5 ± 5.6 

  **L Knee            **Pre-treatment**   171.3 ±     2.8 ± 6.4
  extension**                             11.0        

                      **Week 52**         174.1 ± 6.3 
  ------------------- ------------------- ----------- ------------------------

*Reviewer's comment: The increase in ROM for some joints was modest,
although the mean changes seem to be favorable to the laronidase
treatment. Caution should be exercised in the interpretation of this
unblinded uncontrolled study in correlating the modest ROM changes to
improvements seen in daily activities.*

#### **[Cardiac Function]{.underline}**

The subjects in this study exhibited typical MPS I cardiac disease,
including valvular insufficiency, pulmonary hypertension, and congestive
heart failure, although only Subject 006 was in serious heart failure at
the start of the study.

At Week 26, 3 of 10 subjects had improvements in NYHA scores. After 52
and 104 weeks of treatment, NYHA scores improved in 10 of 10 and 9 of 9
subjects, respectively, with 6 subjects achieving normal scores of Class
I. No subject was in Class I at pretreatment.

Tricuspid regurgitation also modestly improved some subjects.

*Reviewer's comment: The data suggest inconsistent echocardiographic
improvement in a few subjects with underlying cardiac disorders in this
small uncontrolled study. In contrast the improvement seen using the
NYHA scores is more open to the bias inherent in open label studies.
These findings may not be surprising in view of the lack of effect of
laronidase on GAG accumulation in heart valve and myocardium in the
canine model of MPS I.*

#### **[Polysomnography and airway evaluations]{.underline}**

Six subjects who had sleep apnea at pre-treatment demonstrated
improvement in the number of apnea episodes by week 26. Five of the 9
subjects with pre-treatment hypopneas showed improvement in the number
of hypopneas per night by week 26. The apnea hypopnea index (AHI)
improved in 7 out of 10 subjects, and the mean AHI decreased from 2.08
to 0.97 (53% reduction) at week 26. However, some subjects had worsening
of some parameters.

Other measures of airway function (airway index and tongue diameter)
showed inconclusive results, in part due to technical difficulties

#### **[Eye disease]{.underline}**

Three subjects had improvement in visual acuity by week 52, and with
additional favorable changes noted at week 104. No changes were observed
in intra-ocular pressure or in corneal clouding.

#### **[CNS abnormalities]{.underline}**

MRI studies of the brain and cervical cord pretreatment demonstrated the
substantial pathology expected in MPS I patients. This included
perivascular storage, meningeal thickening and spinal cord compression
or restriction, and miscellaneous other findings.

There were no substantial changes seen on MRI during the 104-week course
of laronidase treatment.

*Reviewer's comment: These findings are consistent with the lack of
enzyme activity in the central nervous system. They are also similar to
those pre-clinical studies showing absence of CNS effects in dogs
affected by MPS I.*

#### **[Bone evaluations]{.underline}**

No significant changes were observed in the genetic skeletal surveys
performed during the study. All subjects had radiologic evidence of
odontoid dysplasia and dysostosis multiplex, commonly seen in patients
with MPS I.

#### **[Height and weight]{.underline}**

In 6 pre-pubertal subjects, height increased by a mean of 6.0 cm at Week
52 and a mean of 10.0 cm at Week 104. Weight increased by a mean of 4.2
kg at Week 52 and a mean of 7.9 kg at Week 104 in these subjects.

Height growth rate normalized for 3 of 6 pre-pubertal subjects at Week
52. Weight growth rate normalized for 2 of the 6 pre-pubertal subjects
at Week 52.

#### **[Pharmacokinetics]{.underline}**

Intravenous administration of laronidase (125,000 U/kg) resulted in
significant circulating plasma IDU activity levels of IDU for periods of
3 hours or more.

The circulating levels of IDU achieved peak at 100-200 U/ml for the
majority of infusions, which was approximately 10 times the half-maximal
uptake of the enzyme in vitro.

The mean circulating half-life (t½) of IDU was approximately 1.8 to 1.9
hours at Weeks 1 and 2 and decreased to 1.2 to 1.4 hours at Weeks 12 and
26 in 7 of the 10 subjects.

Differences in pharmacokinetic parameters did not correspond to
differences in urinary GAG excretion.

In examining the question of factors responsible for variations in
pharmacokinetic parameters, the sponsor found that presence of
antibodies to laronidase did not correlate with a decrease in terminal
half-lives by linear regression analysis. The 3 subjects with consistent
IDU-specific antibodies did not have consistent and clear
changes---either increased or decreased half-life---compared to patients
without IDU-specific antibodies.

In addition, no relationship was found between urinary GAG levels,
enzyme activity in buccal mucosa brushings and pharmacokinetic
parameters.

#### **[Enzyme uptake into buccal mucosa and leukocytes]{.underline}**

Prior to treatment all subjects had very little or undetectable α - L
--iduronidase in their buccal mucosa or peripheral leukocytes.

By the Week 2 pre-infusion assessment, enzyme was detectable in the
buccal mucosa, reaching an average of about 1% of normal in all
patients. Leukocyte enzyme levels have also shown persistently higher
levels during treatment (mean of 18%, 12% and 35% of normal at weeks 26,
52 and 104 respectively.

[]{#__RefHeading___Toc27725166 .anchor}Safety

#### **[Adverse events]{.underline}** 

All 10 subjects had at least 1 adverse event, and at least one deemed to
be study drug-related. There were a total of 960 adverse events
reported. Eight subjects experienced 32 serious adverse events,
including 2 that resulted in death. Seven subjects had 33 adverse events
reported as severe.

The most common adverse events reported during the study were: rhinitis
(10 subjects), pain, asthenia and fever (9 subjects each), and increased
cough, abdominal pain, vascular disorder, and rash (8 subjects each).

The most common of the 33 severe adverse events reported during the
study were: bone disorder (including cervical cord compression and
spinal deformities), apnea and vascular disorders, allergic reactions
and headaches. Ten of these 33 severe events were judged to be
definitely or possibly related to the study drug. Fourteen of these 33
severe adverse events were also serious adverse events.

Adverse events were also classified by having occurred on an infusion
date after the start of the infusion or as having occurred in
non-infusion days. The infusion day adverse events reported by most
subjects were: rash, urticaria, allergic reactions and headaches and
adverse events with the greatest occurrences were: urticaria (97
events), rash, and angioedema.

All subjects were pre-medicated with diphenidramine intravenously before
the laronidase infusion, and some subjects also received corticosteroids
and nonsteroidal anti-inflammatory drugs. If a reaction occurred during
an infusion, the rate of infusion was slowed or temporarily stopped, the
dosage could temporarily be reduced, additional doses of diphenidramine
or corticosteroids could be administered or other interventions could be
performed.

*Reviewer's comment: Approaches to prevent or treat an infusion reaction
were so varied that guidelines for a label would be problematic.*

#### **[Deaths]{.underline}**

There were 2 deaths that occurred during the 152-week portion of the
study.

Subject 008, age 7, died 4 days after the Week 103 infusion, of apnea
(respiratory arrest). Respiratory distress occurred during a flight for
the Week 104 assessment, followed by respiratory arrest, without
response to intubation and full CPR efforts.. Autopsy findings indicated
an apparent systemic viral illness with histologic evidence of an active
lymphocytic myocarditis and patchy bronchiolitis. Subject 008 had a high
antibody titer, including IgG specifically to laronidase, which
persisted until the last assessment at week 100. Complement activation
was seen at weeks 6 and 12, but not subsequently. Autopsy findings
included mild immune complex deposits in glomerular basement membranes,
and mild focal deposition of IgM in lung capillaries with minimal C3,
but without any pathologic change by light or electron microscopy in
either organ to suggest a functional effect. The subject's residual
underlying MPS I disease and/or viral illness may have contributed to
death. This subject had received weekly infusion premedication with
methylprednisolone starting at Week 8 and continuing throughout the
study due to hypersensitivity-type reactions. Study drug did not appear
to be directly implicated based on history and autopsy findings.

*Reviewer's comment: This death is likely related to acute complications
of a viral illness in a subject with severe manifestations of the
disorder. The use of systemic steroids as pretreatment for the enzyme
infusions may have also contributed.*

Subject 002, age 13, died 19 days after the subject's last study
infusion at Week 137, of cardiac and respiratory arrest. This subject
had a significant medical history of musculoskeletal disease at study
enrollment, including scoliosis. The subject was admitted to the
hospital for posterior spinal fusion for worsening of her scoliosis from
T5 to L4. Postoperatively, the subject was unable to move the lower
extremities, and through additional testing and procedures, was
diagnosed with spinal cord injury and ascending quadriparesis which
progressed to respiratory failure. The subject and family requested
discontinuation of the ventilation leading to the subjects death.

#### **[Laboratory Abnormalities]{.underline}**

[Serum Chemistries]{.underline}: Most subjects had elevated serum levels
of alkaline phosphatase at screening and pre-treatment. These levels
generally decreased by week 8, although for some subjects levels
declined and remained above normal for the study period. One subject had
an elevated serum LDH level at week 8, which returned to normal by week
10. One subject had an episode of presumed macrolide hepatotoxicity from
week 26 until week 30.

[Hematology]{.underline}: Several subjects had chronic anemia at
pre-treatment and the indices related to red blood cell remained stable
throughout the study period.

#### **[Antibody development]{.underline}**

All subjects developed IgG antibodies to the laronidase product as
detected by ELISA by week 6 or 12 of treatment. Serum antibody levels
generally declined over time. Using a Western blot technique, the
sponsor determined that the initial antibodies detected were directed
against a 60 KD protein impurity. Specific immune responses to rhIDU
were seen in 4 subjects by Western Blot which were either transient or
declined with time.

IgG titer did not correlate with hypersensitivity-type reactions in
these patients.

There was no apparent correlation between IgG antibody titer to
laronidase product and reductions in excess urinary GAG levels, liver or
spleen size. These antibodies did not neutralize enzyme activity.

Complement activation, as measured by the difference between the pre-and
postdose levels of CH50 and either C3 or C4, was highest at Week 6 or 12
in 4 subjects, but was greatly reduced or resolved by Week 26 and absent
at Week 52. There was no correlation between complement activation and
need to receive glucocorticoids as pre-medications for infusion or to
manage hypersensitivity-type reactions during infusions. There were no
apparent effects of the immune responses on development of immune
complex disease or on glomerulonephritis based on urinalysis and GFR
results.

###### Summary {#summary .Style2}

This uncontrolled Phase 1 study of laronidase in 10 subjects with MPS I
was able to demonstrate bioactivity in clinical areas that correspond to
large accumulation of GAG's such as the reticulo-endothelial system and
the kidneys, resulting in substantial reductions of hepatosplenomegaly
and excretion of urinary GAG's. An effect on other endpoints,
particularly of clinical significance, was not demonstrated in this
study. Some data suggested a favorable trend, but it is imperative to
note that these data obtained from an open label uncontrolled study
cannot provide support for laronidase efficacy in MPS I.

All subjects had infusion associated reactions, which were mild or
moderate. All subjects had antibodies to laronidase as assessed by
ELISA, but specific anti-IDU antibodies were confirmed in 4 subjects. 2
deaths occurred during this study, but these seem to be unrelated to the
study drug, and consistent with the natural history of the severe
presentation of MPS I.

[]{#__RefHeading___Toc27725172 .anchor}Study ALID-003

###### Overview {#overview-1 .Style2}

This is the only Phase 3, double blind, placebo-controlled, randomized
clinical trial conducted for this product to support a claim of efficacy
and safety in the treatment of patients with MPS I. The study started on
December 28, 2000 and was completed on September 6, 2001.

At the end of the 26-week study period, all subjects were offered
participation in an open label extension study (ALID-006).

###### Protocol {#protocol-1 .Style2}

**Title:** "A Randomized, Double-Blind, Placebo-Controlled, Multicenter,
Multinational, Clinical Study of Recombinant Human Alpha-L-Iduronidase
in Patients with Mucopolysaccharidosis Type I". Protocol ALID-003-99.

[]{#__RefHeading___Toc27725175 .anchor}Design

This was a randomized, double-blind, placebo-controlled, multicenter,
multinational study. The study was divided into 2 consecutive phases: a
2-week period to assess eligibility and obtain baseline parameters, and
a 26-week treatment phase in which subjects are randomized to receive
weekly laronidase or placebo.

[]{#__RefHeading___Toc27725176 .anchor}Objectives

-   [Primary]{.underline}: assess treatment-related changes in
    parameters of physiological and functional importance to subjects
    with MPS I to support a claim of efficacy of laronidase in the
    treatment of these various conditions.

-   [Additional objective]{.underline}: pharmacokinetic assessment in a
    subset of study subjects and exploring changes in pharmacokinetic
    parameters over time.

-   [Safety]{.underline}: assess the incidence of adverse events,
    including laboratory parameters, vital signs, physical examination,
    cardiac parameters and immunogenicity.

[]{#__RefHeading___Toc27725177 .anchor}Eligibility Criteria

**Inclusion criteria:**

-   Male or female, and aged five years or older.

-   Documented diagnosis of MPS I, confirmed by measurable clinical
    signs and symptoms of MPS I, and a documented fibroblast or
    leukocyte α-L-iduronidase enzyme activity level of less than 10% of
    the lower limit of the normal range of the measuring laboratory.

-   Negative pregnancy test (urine β-hCG) for female subjects of
    childbearing potential at baseline and use effective contraception
    throughout the study. Sexually mature males also must use effective
    contraception.

-   Capable of standing independently a minimum of six minutes and
    walking a minimum of five meters within six minutes.

-   Capable of performing a reproducible FVC maneuver.

-   Baseline FVC value that is less than or equal to 80% of his/her
    predicted normal FVC value based on Polgar predicted values for
    standing height for children five through seven years of age and the
    Hankinson predicted values for patients aged 8 and above.

**Exclusion criteria:**

-   Prior tracheostomy.

-   Prior bone marrow transplantation.

-   Pregnant or lactating.

-   Use of an investigational drug within 30 days prior to study
    enrollment.

-   Medical condition, serious intercurrent illness, or extenuating
    circumstance that may significantly interfere with study compliance.

-   Known hypersensitivity to laronidase or to components of the active
    or placebo test solutions.

[]{#__RefHeading___Toc27725178 .anchor}Treatment assignment /
Randomization

Eligible subjects were randomized to the laronidase or placebo group
according to a central randomization scheme blocked by site. All
subjects, investigators, site personnel, and members of the sponsor's
staff were masked to the treatment assignment. The computer-generated
randomization codes were held by Genzyme Corporation.

[]{#__RefHeading___Toc27725179 .anchor}Product information and
administration

Subjects randomized to the treatment group received laronidase at a dose
of 100 U / kg intravenously weekly during the treatment phase for 26
weeks. Placebo subjects received a pH-adjusted, phosphate-buffered
solution. Study solutions were infused weekly, with a minimum interval
between consecutive infusions being 4 days.

For administration to subjects, the laronidase or placebo were diluted
with between 100 mL to 250 mL (depending on the subject's weight) of
0.1% human serum albumin in saline.

All subjects were pretreated 30 minutes to one hour prior to infusion
with an antipyretic regimen (acetaminophen or ibuprofen) and an
antihistamine regimen (diphenhydramine, hydroxyzine, chlorpheniramine,
cetirizine, fexofenadine or loratadine).

The initial infusion rate of 0.01 mg/kg (2 U/kg) of body weight per hour
for 15 minutes was incrementally increased if well tolerated to a
maximum of 0.25 mg/kg (43 U/kg) of body weight per hour to deliver the
total volume of the infusion over approximately 4 hours. The total
infusion volume for subjects weighing between 5 and 20 kg was 100 mL and
for subjects weighing between 21 and 100 kg was 250 mL

If a patient was unable to receive a scheduled treatment infusion within
the 10-day maximum period allowed following the last scheduled infusion,
that patient received a treatment infusion at the earliest possible
date. After such an out-of-schedule treatment infusion, the next
infusion was given within 7 ± 3 days. Subsequent treatment infusions
were given according to the original weekly treatment infusion schedule.

[]{#__RefHeading___Toc27725180 .anchor}Evaluations

(baseline and Weeks 4, 8, 12, 16, 20, 26 except as noted)

a\. Forced Vital Capacity (FVC)

b.  Six-minute walk distance, reported in meters walked. Baseline exam
    repeated 3 times for training, and third trial used as baseline.

c.  Children's Health Assessment Questionnaire (CHAQ) for subjects 5
    --18 years of age or Health Assessment Questionnaire (HAQ) for
    subjects 19 years of age or older. (assessed at baseline, weeks 4,
    12, and 26)

d.  Sleep study (to measure apnea/ hypopnea events and oxygen
    desaturation) are assessed at baseline, and weeks 4, 12, and 26

e.  Liver volume by MRI at baseline and week 26

f.  Urinary Glycosaminoglycans (GAG)

g.  Joint Range of Motion at baseline and weeks 12 and 26

h.  Child Health Questionnaire or SF-36 at baseline and weeks 12 and 26

i.  Resource utilization

j.  Standing heights for measurement of growth velocity

k.  Investigator global assessment at week 26

l.  Visual acuity by standard eye chart testing, ocular pressure,
    corneal clouding, and retina / optic nerve exam at baseline and week
    26

m.  EKG and echocardiogram at baseline and week 26

n.  FEV~1~, total lung capacity and diffusing capacity at baseline and
    week 26

o.  Parent/caregiver quality of life at baseline and week 26

p.  Pharmacokinetic assessments at 2 selected sites for all enrolled
    subjects at those sites at week 1, 12 and 26, with samples collected
    at pre-dose, 15, 45, 90 minutes of infusion, 3 and 4 hours of
    infusion, 10, 30, 45, 60 minutes post-infusion, 2, 3, 4 and 6 hours
    post-infusion.

q.  Medical history, VS, and physical examination

r.  Brain / cranio-cervical junction MRI at baseline (all subjects) and
    at the investigator's discretion at week 26

s.  Laboratory evaluations at baseline and weeks 4, 12 and 26, including
    clinical chemistry, hematology and urinalysis. Urine pregnancy test
    for females of childbearing potential at baseline and every 4 weeks.

t.  Antibody testing at baseline and every 4 weeks. Complement
    activation (CH100 or CH50 and C3 or C4 components) was measured if
    symptoms of a hypersensitivity reaction are noted.

u.  Adverse events

[]{#__RefHeading___Toc27725181 .anchor}Safety Monitoring

An independent Allergic Reaction Review Board (ARRB) was created to
review signs of moderate or severe hypersensitivity and provide guidance
on management of these reactions. The ARRB interacted with the Genzyme
Pharmacovigilance group and infrequently directly with investigators.

[]{#__RefHeading___Toc27725182 .anchor}Endpoints

-   Primary efficacy (co-primary endpoints):

    a.  Mean change from baseline to week 26 in the percent predicted
        FVC value based on standing height

    b.  Mean absolute change from baseline to week 26 in the 6 minute
        walk (in meters)

-   Secondary efficacy:

    a.  Apnea / Hypopnea Index

    b.  Hepatomegaly

    c.  Children's Health Assessment Questionnaire (CHAQ) / Health
        Assessment Questionnaire (HAQ)

    d.  Urinary GAG's

-   Tertiary Efficacy:

    a.  Global status Child Health Questionnaire given to children 5 to
        18 years old or the Short Form -- 36 given to adult subjects

    b.  Growth Velocity for pre-pubertal subjects

    c.  Visual Acuity

    d.  Cardiac Function Testing by electrocardiogram and echocardiogram
        parameters

    e.  Investigator Global Assessment

    f.  Forced Expiratory Volume in One second (FEV1)

    g.  Total Lung Capacity

    h.  Diffusing Capacity

    i.  Parent / Primary Caregiver QoL

    j.  Resource Utilization

*Reviewer's comment: The primary efficacy endpoint of percent predicted
FVC was modified to include different formulas to calculate the variable
according to age categories (Polgar for ages 5 -- 7 years and Hankinson
for subjects 8 years of age or older at baseline). The percent predicted
FVC was again revised at the study conclusion to be calculated with
reference to baseline height, instead of the current height at the time
of spirometry assessment at week 26. Secondary and tertiary endpoints
were modified as follows:*

*The sleep study endpoint was clarified further to include measures of
electroencephalogram, electromyogram, nasal and oral airflow, chest and
abdominal movement, oxygen saturation, and rapid eye movement. The data
would be transferred to a core laboratory at New York University and
interpreted in a blinded fashion. During the course of the blinded
reading, the independent expert noted a substantial proportion of
subjects with normal AHI scores at baseline and recommended a subset
analysis of the most severely affected subjects (AHI scores ≥ 10 for
children younger then 15 years and AHI scores ≥ 15 for subjects older
than 15 years) and for all subjects with AHI ≥ 20, in whom clinical
intervention may be warranted.*

*Active shoulder flexion was added as a secondary endpoint, whereas
shoulder extension, knee flexion and extension were added as tertiary
endpoints.*

*The secondary endpoint of CHAQ / HAQ was further defined as the
Disability Index derived from the questionnaires, as a summary score of
activities of daily living. Another component of the CHAQ / HAQ was made
into a tertiary efficacy endpoint as an assessment of the subject's
pain, plotted in a visual analog scale.*

*Urinary GAG's measurements became tertiary endpoints.*

*Visual Acuity was further expanded to included assessments of
tonometry, fundoscopy and slit lamp examinations.*

[]{#__RefHeading___Toc27725183 .anchor}Statistical Analysis

[Sample size]{.underline} was estimated based on the cross-sectional,
non-interventional survey study ALID-004 data in MPS I subjects. A total
sample of 42 subjects (21 per treatment group) provided 80% power to
detect an absolute difference of 15% from a value of 55% in mean percent
predicted FVC from baseline to week 26, assuming a standard deviation of
15% and a dropout rate of 20% and maintaining a Type I error at 5%. The
same total sample size provided 80% power to detect a difference of 125
meters in the mean distance walked comparing baseline to week 26,
assuming a standard deviation of 15% and a dropout rate of 20% and
maintaining a Type I error at 5%.

The final statistical analysis plan was submitted on 9/19/01, 13 days
after conclusion of the study. Genzyme was responsible for data entry
and editing, review of information in the CRF's, statistical analysis
and generation of the clinical study reports.

[Primary efficacy endpoints]{.underline} are analyzed for both the
Intent to Treat (ITT) population and the Per Protocol (PP) population.
ITT population includes all randomized subjects and is the basis for the
efficacy determination. Per Protocol population is defined as all
subjects who received at least one infusion and had no major protocol
violations, e. g. missing more than 5 of the 26 total infusions.
Hypothesis testing is done using Wilcoxon rank-sum test on the change
from baseline to week 26 in the 2 treatment groups for both primary
endpoints. Baseline is defined as the third or final evaluation during
the baseline phase just prior to randomization. This is due to a
potential training effect of performing 3 assessments for FVC and 6
minutes walk distance in a 2-week period.

The study used co-primary endpoints and was to be considered
statistically significant only if [both]{.underline} primary endpoints
meet or exceed the critical p-value of 0.05.

[Secondary and tertiary endpoints]{.underline} are tested for the ITT
population using ANOVA, with treatment group and study site as
independent variables and mean change from baseline for each continuous
secondary and tertiary endpoint as the dependent variable, except for
the Investigator Global Assessment, which is intrinsically a categorical
comparison to baseline. In addition, descriptive statistics are used for
the ITT population to present changes from baseline to all timepoints in
the study, by treatment group. Categorical tertiary endpoints are
analyzed with Fisher's Exact test.

[Missing data]{.underline} for subjects who missed study visits or
terminated the study early are imputed by the last observation carried
forward method, except for safety data or resource utilization data,
which are not imputed.

###### Study Conduct {#study-conduct-1 .Style2}

The study was conducted under IND 7334. Study sites were audited by
representatives of Genzyme Corporation or Genzyme Europe for North
America or European sites, respectively.

Study conduct changes:

-   Antibody confirmation after screening ELISA was changed to a
    radioimmunoprecipitation assay.

```{=html}
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```
-   Amendment 3 submitted on 3/27/01 (3 months into the study) revises
    and expands on the allowed antihistamines and antipyretics to be
    used prior to infusion.

-   Amendment 3 also revises the method to determine the predicted FVC
    values according to the age of the affected subject: Polgar
    predicted values for children 5 to 7 years old and Hankinson
    predicted values for subjects 8 years and older.

*Reviewer's comment: This last change has no effect in the data
collection of FVC, as the calculation of the predicted FVC value for the
purpose of the analysis is not performed at the time of the assessment.*

-   The 6-minute walk test has been developed and validated based on a
    30m long walking path, with subjects making turns each time the full
    length is reached. However, not all centers in this study were able
    to employ a 30m length, and a 15 m length was necessary. In order to
    ensure consistency, all centers were instructed to use the 15m
    length.

*Reviewer's comment: This change ensured that the results would be fair
for comparisons between centers and pooling of the centers. However,
this is not exactly the validated testing tool. Comparison to prior uses
of this evaluation tool, and to standardized normal values may not be
valid. This modification was retained through the extension study as
well.*

[]{#__RefHeading___Toc27725185 .anchor}Database Integrity

Representatives of BioMarin/ Genzyme LLC monitored the study progress in
all sites according to ICH-GCP guidelines.

After completing the final study report for ALID-003 on February 17,
2002, it was ascertained that the joint range of motion data had been
incorrectly recorded at several sites. To maintain the integrity of the
database, the joint range of motion measurements were corrected in the
database. A revised study report was reissued.

[]{#__RefHeading___Toc27725186 .anchor}Protocol violations

Protocol violations were prospectively defined prior to locking the
database as follows:

a.  subject missing more than 5 of the 26 infusions

b.  occurrence of a treatment dispensing error with the subject
    receiving the incorrect drug assignment

c.  tracheostomy performed in a subject during the study

d.  bone marrow transplantation performed in a subject during the study

e.  occurrence of infusion associated reaction classified as severe by
    the investigator

There were numerous protocol deviations in all clinical sites. However,
these deviations did not impact the overall study interpretation. The
majority of the deviations were related to small divergences in timing
of infusion or assessments, or incomplete performance of the required
assessments at a given timepoint. Deviations occurring in 2 subjects
were considered major protocol violations that could impact in the
efficacy analyses; these subjects were excluded from the PP analysis.
The violations were: presence of a significant medical condition (prior
heart transplant and pacemaker implant) in a subject randomized to
placebo and missing 7 of the 26 infusions in a subject randomized to
laronidase. These subjects were included in the ITT analyses, but do not
impair forming conclusions based upon these analyses.

[]{#__RefHeading___Toc27725187 .anchor}FDA site inspection findings

The FDA inspector for the Canadian and United Kingdom sites noted that
either the Polgar normative method (irrespective of the subject's age)
or a non-specified method were used in on-site calculations of the
percent of predicted Forced Vital Capacity (FVC). Since the only % FVC
values generated at the clinical sites were those used in the
determination of eligibility to the study, this does not impact outcome
evaluation.

In addition, the FDA site inspector for the University of North Carolina
uncovered discrepant information for 5 subjects related to assessment of
FVC (in liters) in the pediatric pulmonary lab and the data recorded in
the CRF for the week 26 visit. The sponsor explained that all values for
the pulmonary testing to be recorded in the CRF were supposed to
originate from the testing performed at the pediatric pulmonary lab. In
the North Carolina site, however, the diffusing capacity and total lung
capacity data had to be obtained in the adult pulmonary laboratory,
which also generated redundant data related to FVC and FEV1. The five
subjects had the FEV1 and FVC data obtained in the adult pulmonary
laboratory entered in the CRF erroneously and unknown to study monitors.
These data were used in the sponsor's analyses.

The sponsor will generate an Erratum containing the FEV1 and FVC values
from the pediatric pulmonary laboratory and will re-analyze the FVC
endpoints in the study. Corrected analyses and data files have not been
submitted to FDA as of the date of this document. All analyses in this
document are based on the datasets with the erroneous data included.
However, the preliminary assessment is that these changes are minor, and
will not change any study conclusions

###### Results {#results-1 .Style2}

[]{#__RefHeading___Toc27725189 .anchor}Subject disposition

The study started on December 28, 2000 and completed September 6, 2001.
47 subjects with MPS I enrolled into the study for screening, of whom 2
failed to have reproducible FVC measurements and were excluded. The 45
subjects were randomized, 22 to laronidase and 23 to placebo. All 45
subjects completed the study. The 45 subjects were enrolled in 5 centers
in North America and Europe, with 6 to 12 subjects at each center.

[]{#__RefHeading___Toc27725190 .anchor}Baseline characteristics

Table 6. Study subject baseline characteristics for selected parameters

+-----------------------+-----------------+-------------+-------------+
| **Baseline            | **Category**    | **Placebo** | **L         |
| Characteristic**      |                 |             | aronidase** |
|                       |                 | **n = 23**  |             |
|                       |                 |             | **n = 22**  |
+-----------------------+-----------------+-------------+-------------+
| Gender                | Male            | 11          | 11          |
+-----------------------+-----------------+-------------+-------------+
|                       | Female          | 12          | 11          |
+-----------------------+-----------------+-------------+-------------+
| Race                  | Caucasian       | 21          | 16          |
+-----------------------+-----------------+-------------+-------------+
|                       | Black           | 0           | 0           |
+-----------------------+-----------------+-------------+-------------+
|                       | Hispanic        | 0           | 4           |
+-----------------------+-----------------+-------------+-------------+
|                       | Asian           | 1           | 1           |
+-----------------------+-----------------+-------------+-------------+
|                       | Other           | 1           | 1           |
+-----------------------+-----------------+-------------+-------------+
| Age Group             | ≤ 12 years      | 10          | 12          |
+-----------------------+-----------------+-------------+-------------+
|                       | 13 to ≤ 18      | 8           | 3           |
|                       | years           |             |             |
+-----------------------+-----------------+-------------+-------------+
|                       | 19 to ≤ 65      | 5           | 7           |
|                       | years           |             |             |
+-----------------------+-----------------+-------------+-------------+
| Syndrome              | Hurler          | 1           | 0           |
+-----------------------+-----------------+-------------+-------------+
|                       | Hurler-Scheie   | 19          | 18          |
+-----------------------+-----------------+-------------+-------------+
|                       | Scheie          | 3           | 4           |
+-----------------------+-----------------+-------------+-------------+
| Years since onset of  | Mean ± SD       | 12.7 ± 7.7  | 12.7 ± 8.5  |
| symptoms              |                 |             |             |
+-----------------------+-----------------+-------------+-------------+
| Years since initial   | Mean ± SD       | 8.7 ± 6.1   | 9.4 ± 6.6   |
| diagnosis             |                 |             |             |
+-----------------------+-----------------+-------------+-------------+
| Enzyme activity (%    | Mean ± SD       | 1.9 ± 3.2   | 1.2 ± 2.1   |
| lower normal range)\* |                 |             |             |
+-----------------------+-----------------+-------------+-------------+
| Weight (kg)           | Mean ± SD       | 40.3 ± 13.0 | 35.3 ± 12.4 |
+-----------------------+-----------------+-------------+-------------+
| Height (cm)           | Mean ± SD       | 137.2 ±     | 133.5 ±     |
|                       |                 | 12.1        | 16.1        |
+-----------------------+-----------------+-------------+-------------+

\* Enzyme activity as assessed in skin fibroblasts or leukocytes

Table 7 shows the baseline characteristics for the 2 % FVC and 6 minute
walk distance.

+--------------------------------+---------------+---------------------+
| **Baseline Characteristics**   | **Placebo**   | **Laronidase**      |
|                                |               |                     |
|                                | **n = 23**    | **N = 22**          |
+--------------------------------+---------------+---------------------+
| Mean % Predicted FVC           | 54.2 ± 16.0   | 48.4 ± 14.8         |
+--------------------------------+---------------+---------------------+
| Mean 6 min. walk distance (m)  | 366.7 ± 113.7 | 319.0 ± 131.4       |
+--------------------------------+---------------+---------------------+

[]{#__RefHeading___Toc27725191 .anchor}Study drug exposure

All 45 randomized subjects completed 26 weeks of the study. The mean (±
SD) number of study drug infusions for the placebo group was 25.4 ± 0.9
whereas for the laronidase-treated group was 25.3 ± 1.6 infusions. One
subject in the laronidase group missed 7 infusions, but 6 of these were
due to a hospitalization for aortic stenosis. The most common reasons
for missing infusions were similar for placebo and laronidase and
related to problems in travel arrangements or illness.

[]{#__RefHeading___Toc27725192 .anchor}Primary endpoints

#### **[Percent Predicted Forced Vital Capacity (% FVC)]{.underline}** 

**Primary analysis**

Lung volumes (measured in Liters) vary greatly among individuals due to
extra-pulmonary factors, such as age, height, race and gender. In order
to account for these variations and increase interpretability of the
data, the sponsor proposed the use of % FVC. % FVC is usually calculated
based on the subject's height at the time of assessment of the pulmonary
function.

After the breaking of the blind, the issue of appropriateness of
adjustment of respiratory volume by the current height was reconsidered.
Factors in favor of using baseline height in the calculation of % FVC
were:

-   Height is difficult to measure in subjects with MPS I due to
    skeletal and joint disease leading to abnormal posture, with
    intra-subject variability

-   If true changes in joint stiffness and posture were to occur, there
    would be a change in %FVC even without any change in respiratory
    function. If this were a systematic change in posture, such as a
    lessening of postural abnormalities in the laronidase group, there
    would be a systematic effect to decrease % FVC.

-   Conversely, it was seen that the placebo-treated subjects had an
    apparent 2.7 % decrease in the % FVC without any actual change in
    lung volumes. The actual change in respiratory function (i.e., none
    on average) is better reflected in the % FVC as calculated using
    baseline height.

Assessments for all subjects at baseline and week 26 were completed.
Therefore no imputation for missing data was necessary. Table 8 shows
the changes from baseline to week 26 in median and mean % FVC, as
calculated using both the current height at the time of assessment or
using the baseline height, for both treatment groups.

Table 8. Changes from Baseline (± SD) to Week 26 in median and mean %
FVC

  ----------------------------------- ---------------- ------------- ----------
  **% FVC**                           **Laronidase**   **Placebo**   **p
                                                                     value**

  Mean Baseline                       48.4 ± 14.8      54.2 ± 16.0   

  Mean Week 26 (Baseline Height)      53.7 ± 18.6      53.3 ± 14.2   

  Mean Change (Baseline Height)       5.3              \- 0.6        

  Mean Difference between groups      5.9                            

  Median Change (Baseline Height)     3.0              0.0           0.016 \*

  Mean Week 26 (Current Height)       50.2 ± 17.1      51.5 ± 13.1   

  Mean Change (Current Height)        1.8              \- 2.7        

  Mean Difference between groups      4.5                            

  Median Change (Current Height)      1.0              \- 1.1        0.028 \*
  ----------------------------------- ---------------- ------------- ----------

\*Wilcoxon test

*Reviewer's comment: As discussed above regarding the use of current
height at week 26 or baseline height in the computation of % FVC, the
data on height for the placebo-treated group shows only a modest
increase from a mean (± SD) of 137.2 (± 12.5) cm to 139.0 ± 11.6, a mean
change of 1.8 cm in 26 weeks of study. In contrast, the mean
laronidase-treated group increased the mean height from 133.5 ± 16.1 to
136.5 ± 15.4 cm, a mean change of 3 cm in the 26 weeks of the study.*

In addition to the statistical significance for the treatment effect
between the 2 groups, the sponsor also notes this is an 11% relative
improvement from baseline for the laronidase group (5.3 % / 48.4 %). The
sponsor proposes that this is a clinically significant improvement
according to the American Thoracic Society.

*Reviewer's comment:* *Even as the analysis shows a statistically
significant treatment effect for laronidase, the clinical significance
of the effect size is unclear. Forced Vital capacity has been chosen as
a surrogate for the restrictive component of the pulmonary impairment,
but may not reflect the entire spectrum of impairment seen in other
areas of lung and upper airway function. The fact that eligibility for
this trial was restricted to subjects with impaired lung function (less
than 80% of predicted normal FVC) would be expected to improve the
chances of demonstrating a larger clinical effect, as compared to a
lessened treatment effect that might be seen if subjects with healthier
FVC's were also enrolled.*

**Exploratory Analysis**

**Prospectively Defined Exploratory Analysis**

Analysis of covariance was performed and has shown the retention of the
treatment effect when covariates such as clinical site, baseline FVC,
baseline Apnea Hypopnea Index, baseline Total Lung Capacity, baseline
liver volume, and baseline GAG level are taken into account (p= 0.04).
The ANCOVA was performed using the % FVC as calculated using the current
height.

**Post-hoc Exploratory Analysis**

[Analysis of Forced Vital Capacity, in absolute volume]{.underline}

The laronidase-treated group had a mean (± SD) increase in forced vital
capacity of 0.11 (± 0.14) L, whereas the placebo-treated group had no
change in the mean forced vital capacity (- 0.02 ± 0.13 L; p \< 0.01,
Wilcoxon test). When analyzing the relative change in liters of forced
vital capacity from baseline to week 26, the laronidase-treated group
had a mean (± SD) increase of 12.2 (± 21.9) % increase, whereas the
placebo-treated group had a mean increase of 1.8 (± 18.4) % in forced
vital capacity (p = 0.02, by Wilcoxon test). (Note: Data include the
described incorrect data for the 5 subjects at Site 4. Preliminary
revised analyses do not appear to alter any conclusions)

[Analysis by Study Visit]{.underline}:

Figure 2 demonstrates the effect of laronidase treatment on the % FVC
(calculated with current heights) across the study period, as compared
to control.

![](media/image3.wmf){width="6.05in" height="4.18125in"}

Note: 4 missing values for Week 4 were imputed by LOCF.

Mean % FVC was lower in the laronidase-treated group than the placebo
group at baseline. From baseline to week 4 a tendency to converge the
lines for the 2 treatment groups is seen. This is due to a small
increase in %FVC in the laronidase group, but a larger acute decline in
%FVC in the placebo group. While the placebo-treated subjects had a
relatively constant mean % FVC for the remainder of the study,
laronidase-treated subjects had a small decline in mean % FVC from week
8 to week 20. There was a tendency for the 2 curves to converge by the
end of the 26 week study period, primarily because of a rise of % FVC in
the laronidase-treated group between weeks 20 and 26.

*Reviewer's comment: The sponsor explains the drop in % FVC seen between
weeks 8 and 20 in the laronidase-treated group as possibly related to a
combination of various factors, including intercurrent illness,
assessment following an infusion, seasonal effects or subject fatigue
from repeat study visits. However, given the size of the sample and the
homogeneous distribution of disease severity in the 2 treatment groups,
one would expect to observe the same factors playing a role in the
control arm, which did not show a decline in FVC. Two subjects in the
laronidase-treated group had significant worsening in the %FVC between
weeks 12 and 20, not explained by a correlation with AE's or use of
concomitant medications.*

*The rise in % FVC between week 20 and week 26 in the laronidase-treated
group is notable. Three laronidase-treated subjects had a substantial
rise in % FVC in that time period. Subject 30608 manifested an increase
from 59.4 % to 80.6 % of the normal predicted FVC, without an obvious
explanation; Subject 30806 increased % FVC from 40 % to 53.7 %, which
could be explained on the basis of recovery from a series of SAE's,
starting with severe CHF diagnosed at week 12, secondary to severe
aortic stenosis, complications of aortic valvuloplasty, with cardiac
arrest, pneumonia and sepsis; and Subject 61010 also had an unexplained
significant rise in % FVC from 17 to 30.9 %.*

*On the other hand, the placebo-treated group had a remarkable but
unexplained drop in the % FVC from Baseline to week 4, with subsequent
stabilization of %FVC's until week 26. The drop cannot be attributed to
a training effect during the 3 baseline assessments made because it was
not observed in the laronidase group. Placebo-treated Subject 60603 had
a substantial drop from baseline to week 4 in the order of 23 points in
the %FVC (clearly an outlier for both groups in the magnitude of drop).
A sensitivity analysis excluding this subject maintains the treatment
effect seen (6.4 %) with a p = 0.04.*

*However, the importance of this initial, but not continuing, decline in
%FVC to the analysis is illustrated by the sensitivity analysis of
comparing the change from baseline to week 26 in the laronidase-treated
group and the change from week 4 to week 26 in the placebo-treated group
(in other words, considering week 4 as the "baseline" for the
placebo-treated group) would eliminate the treatment effect observed in
the ITT population, with a difference from placebo of 2.5 % (p=0.22).*

[Analysis by Study Center]{.underline}: There was general consistency in
study outcomes for this endpoint. In 4 of the 5 clinical sites,
placebo-treated subjects experienced worsening of the % FVC and
rhIDU-treated subjects showed improvement in this primary endpoint. In
one center (Canada), the laronidase-treated subjects did not show
improvement of % FVC, whereas placebo-treated subjects did.

[Analysis by Gender]{.underline}: Table 9 shows the mean (± SD) baseline
and changes from baseline to week 26 in % FVC (as calculated from
current heights) by gender.

Table 9. Mean % FVC baseline and changes from baseline to week 26
according to gender

  ------------ ------------- ---------- --------- -------- ---------------- ---------- --------- --------
  **Gender**   **Placebo**                                 **Laronidase**                        

               n             Baseline   Week 26   Change   n                Baseline   Week 26   Change

  Female       12            54.1 ±     53.1 ±    \- 1.0   11               55.9 ± 9.9 59.2 ±    3.3
                             13.1       11.8                                           15.4      

  Male         11            54.4 ±     49.8 ±    \- 4.6   11               40.9 ±     41.2 ±    0.3
                             19.4       14.8                                15.5       14.1      
  ------------ ------------- ---------- --------- -------- ---------------- ---------- --------- --------

(Note: Data include the described incorrect data for the 5 subjects at
Site 4.

Preliminary revised analyses do not appear to alter any conclusions)

*Reviewer's comment: The treatment-associated difference in change from
baseline was similar for both males and females, but males fared worse
than females within each treatment groups. Most of the overall between
groups difference in the %FVC comes from FVC increase in
laronidase-treated females with FVC decline in placebo-treated males. It
is also notable from data shown in Table 9 that laronidase-treated males
had substantially worse mean % FVC at baseline and at week 26 compared
to females or placebo treated males. Both of these observations are
illustrated in Figure 3.*

Figure 3. Mean % FVC (calculated using current heights) across the study
visits plotted by gender and treatment groups

![](media/image4.wmf){width="6.25in" height="4.663888888888889in"}

[Analysis by Age Category]{.underline}: Table 10 shows the mean % FVC at
baseline and change from baseline to week 26 in the 2 treatment groups
subdivided by age category tertiles.

Table 10. Mean % FVC baseline and changes from baseline to week 26
according to age category.

  ------------ ------------- -------------- --------- ------------ ---------------- -------------- --------- ------------
  **Age        **Placebo**                                         **Laronidase**                            
  category**                                                                                                 

               **n**         **Baseline**   **Week    **Change**   **n**            **Baseline**   **Week    **Change**
                                            26**                                                   26**      

  **≤ 12**     10            62.1 ± 11.6    56.1 ±    -6.0         12               51.5 ± 14.9    53.5 ±    +2.0
                                            10.3                                                   18.8      

  **13 -- 18** 8             44.1 ± 17.1    45.6 ±    +1.5         3                44.5 ± 8.4     44.3 ±    -0.2
                                            15.0                                                   5.8       

  **19 -- 65** 5             54.8 ± 15.3    51.9 ±    -2.9         7                44.8 ± 17.4    47.1 ±    +2.3
                                            14.0                                                   17.7      
  ------------ ------------- -------------- --------- ------------ ---------------- -------------- --------- ------------

(Note: Data include the described incorrect data for the 5 subjects at
Site 4.

Preliminary revised analyses do not appear to alter any conclusions)

*Reviewer's comment: Approximately half of the subjects were younger
than 12 years, limiting the ability to form comparisons between age
subset. No clear pattern of differential in between group differences
was apparent.*

[Analysis by Race / Ethnicity]{.underline}: The great majority of
subjects were Caucasian, and no meaningful comparisons were possible
among the races to examine the treatment effect.

[Analysis by severity of FVC impairment at baseline]{.underline}:
Biomarin performed an analysis dividing the treatment groups roughly in
half based on the study-aggregate median baseline %FVC. Biomarin
observed that subjects with milder pulmonary disease at baseline did
better than subjects with lower FVC at baseline (p=0.04) with an 8.6 %
difference between groups in the milder pulmonary severity subset
compared to -- 0.3 % difference in the more severely affected
individuals at baseline.

*Reviewer's comment: This observation suggests that the laronidase
effects may be more easily distinguished from that of the control arm
when irreversible structural changes did not take place yet.*

*One needs to keep in mind that % FVC is mostly an index of pulmonary
function, but other parameters, such as liver volume could possibly have
impact on the amount of restriction being assessed. Hepatosplenomegaly,
as seen in both the Phase 1 study as well as in the present study (see
below) is reduced in the laronidase-treated group.*

*Table 11* shows the mean changes from baseline to week 26 in the %
predicted FVC among the 4 quartiles of baseline severity in % FVC.

Table 11. Mean changes (± SD) from baseline to week 26 in % FVC by the
quartiles of severity at baseline

+-----------+-------------+-------------+----+-----------------+----+
| *         | **range %   | **L         | *  | **Placebo**     | *  |
| *Severity | FVC**       | aronidase** | *N |                 | *n |
| level**   |             |             | ** |                 | ** |
+-----------+-------------+-------------+----+-----------------+----+
| **least** | 77.4 --     | 10.3 ± 8.6  | 4  | -2.5 ± 3.9      | 7  |
|           | 65.4        |             |    |                 |    |
| **most**  |             |             |    |                 |    |
+-----------+-------------+-------------+----+-----------------+----+
|           | 65.4 --     | 6.1 ± 8.6   | 6  | -3.2 ± 8.9      | 6  |
|           | 51.9        |             |    |                 |    |
+-----------+-------------+-------------+----+-----------------+----+
|           | 51\. 9 --   | 2.2 ± 12.3  | 6  | 0.9 ± 6.0       | 5  |
|           | 41.6        |             |    |                 |    |
+-----------+-------------+-------------+----+-----------------+----+
|           | 41.6 --     | 4.2 ± 6.5   | 6  | 3.9 ± 5.3       | 5  |
|           | 15.5        |             |    |                 |    |
+-----------+-------------+-------------+----+-----------------+----+

(Note: Data include the described incorrect data for the 5 subjects at
Site 4.

Preliminary revised analyses do not appear to alter any conclusions)

*Reviewer's comment: In the laronidase-treated group, there is a
suggestion of greater improvement in % FVC among the less severely
affected subjects, However the placebo group suggests a trend towards
less decline of FVC with increasing severity. The consistent gradual
lessening of the treatment associated difference as severity increases
suggests the possibility that laronidase has less benefit in subjects
with more advanced pulmonary restriction.*

[Analysis of subject distribution according to gender, age category,
treatment assignment and severity of % FVC at baseline]{.underline}

As seen from the exploratory analyses of the FVC data changes in the two
treatment groups by subsets in gender and severity, these demographic
factors may have influenced the observed treatment effect. The total
subject number is highly limited in this study, and there is potential
that imbalances of subject distribution in one of these factors could
have an effect on a subset analysis intended to examine a different
factor.

The gender and baseline severity factors appear to have a potential
interaction with treatment effect. While within the placebo group there
is a uniform distribution of each gender across the severity categories,
the laronidase group is problematic. Somewhat more female laronidase
subjects are in the lower two severity categories (7:4) while somewhat
more male laronidase subjects are in the two more severe categories
(3:8). This inverse imbalance leads to the problem that within the
laronidase group, it is difficult to distinguish between a gender
related factor (i.e., female patients did better on laronidase than
male) versus a severity related factor (i.e., less severe patients on
laronidase did better than more severe). Thus, conclusions regarding the
previous subset explorations may be difficult.

[Immunogenicity]{.underline}: The ELISA assay provided was somewhat
non-specific to laronidase, probably because of cross reactivity with a
60 kD protein impurity present in the final product. By the ELISA assay,
all laronidase-treated subjects became seropositive while 5
placebo-treated subjects were also ELISA positive. The anti-laronidase
antibody became detectable early in the study, between weeks 4 and 8.
There was no correlation between the ELISA determined antibody levels
and the % FVC change from baseline at week 26.

Radioimmunoprecipitation (RIP) was used as a confirmatory assay for the
ELISA. While highly specific to laronidase as a substrate, RIP is a
qualitative assay only. 20 of 22 laronidase-treated subjects developed
RIP-based anti-laronidase antibodies.

*Reviewer's comment: Nearly all laronidase subjects became antibody
positive. Comparisons between seropositive and seronegative
laronidase-treated subjects are not informative.*

[Analysis by baseline enzyme level]{.underline}: There was no
correlation between the baseline enzyme levels and the baseline %FVC or
the change in % FVC at week 26 from baseline in the group as a whole or
the 2 treatment groups.

[Analysis by change in height]{.underline}: No discernible trends were
seen in comparing the change in subjects heights during the 26 weeks of
study with their change in FVC.

#### **[Six minute walk distance (meters)]{.underline}**

**Primary analysis**

After 26 weeks of the study, subjects in the laronidase group had a
median increase of 27.5 meters in the 6 minute walk distance, while
subjects in the placebo group showed a median decrease of 11.0 meters
walked in the 6 minute interval. The overall difference, as analyzed by
the Wilcoxon rank sum test, did not reach statistical significance
between the treatment groups (Table 14). Assessments for all subjects at
baseline and week 26 were completed and no missing values were present.

Table 12. Changes from Baseline to Week 26 in 6 minute walk distance (in
meters)

+--------------------------------+-------------+-------------+--------+
|                                | *           | **Placebo** | **p    |
|                                | *Laronidase |             | v      |
|                                | (n=22)**    | **(n=23)**  | alue** |
+--------------------------------+-------------+-------------+--------+
| **Mean Baseline (m)**          | 319.1 ±     | 366.7 ±     |        |
|                                | 131.4       | 113.7       |        |
+--------------------------------+-------------+-------------+--------+
| **Mean Week 26 (m)**           | 338.8 ±     | 348.3 ±     |        |
|                                | 127.1       | 128.8       |        |
+--------------------------------+-------------+-------------+--------+
| **Mean Change (m)**            | 19.7        | \- 18.4     |        |
+--------------------------------+-------------+-------------+--------+
| **Difference between groups**  | 38.1        |             |        |
+--------------------------------+-------------+-------------+--------+
| **Median Change**              | 27.5        | -11.0       | 0.07   |
|                                |             |             | \*     |
+--------------------------------+-------------+-------------+--------+

\*Wilcoxon test

*Reviewer's comment: The trend was favorable to laronidase effect, but
statistical significance was not reached. The clinical significance of
this difference is also unclear. This endpoint was selected because the
distance walked in the 6 minute walk test is an assessment of overall
function and has the opportunity to demonstrate a clinically meaningful
effect. Walk distance probably indicates a measure of heart function,
lung function, joint and neuromuscular function, all of these affected
in subjects with MPS I, to a greater or smaller extent.*

*Unlike %FVC, there was no effort to limit enrollment to subjects
substantially affected in their capacity to walk, which may have limited
the ability to observe a clinical effect and contributed to lack of
statistical significance. However, a sensitivity analysis conducted
post-hoc comparing the effect of laronidase treatment to placebo in
subjects above and below the median failed to demonstrate an effect of
the test drug in the more severely affected subjects. Please refer to
this and other sensitivity analyses described below.*

**Exploratory Analysis**

**Prospectively Defined Exploratory Analysis**

Analysis of covariance was performed with center, baseline 6 minute walk
distance, gender, baseline standing height, and baseline liver volume
used as covariates. In this model, the treatment effect p-value achieved
statistical significance (p=0.04). This treatment effect was seen in the
ANCOVA after controlling for the significant covariates of gender
(p=0.02) and baseline 6 minute walk distance (p \< 0.001).

[Analysis by Study Visit]{.underline}: Figure 4 and Figure 5 demonstrate
the effect of laronidase treatment on the 6 minute walk distance across
the study period, as compared to control.

Figure 4. Mean (± SD) distances during Study 003 by treatment group

![](media/image5.wmf){width="6.763194444444444in"
height="4.166666666666667in"}

*Reviewer's comment: Because the 2 lines seem almost superimposed, the
following figure amplifies the range 250 to 450 meters where the subtle
changes in distance walked were observed*

Figure 5. Mean (± SD) distances walked across the 26 weeks of Study 003
by treatment group, plotted in the range where the changes occurred

![](media/image6.wmf){width="6.05625in" height="4.215277777777778in"}

*Reviewer's comments: The drop observed for both treatment groups
between baseline and Week 4 is attributed to the training effect
obtained by selecting the third measurement of this test in a period of
approximately 7 days for determination of baseline. There is a small but
consistent increment in distance between the first and the third of
these assessments. The effect of training is likely lost after a 4 week
interval. Three trials were not used for the subsequent assessments. The
same training effect was not observed in the analysis among the 3
baseline measures of % FVC for determination of the baseline value for
that endpoint.*

*The two groups were not identical in walking capacity at baseline, with
the laronidase group walking lesser distances. However, unlike the data
shown for the % FVC, here there is small but consistent improvement in
the distance walked in 6 minutes in the laronidase-treated group, even
if with unclear clinical significance. Unlike the graphic shown for the
% FVC by study visit, the laronidase-treated group does not show a
difficult to interpret mean increase in the Week 20 to Week 26
interval.*

[Analysis by Gender]{.underline}

*Reviewer's comment: Further analysis into the covariates that drove the
statistical significance in this ANCOVA has demonstrated that the trend
to favorable treatment --associated difference is largely from female
subjects, as shown in Table 13 and Figure 6. These findings are similar
to those related to laronidase effects on % FVC by gender; where only
laronidase-treated females showed improvement. Unlike the % FVC data,
there was no difference between groups in the change from baseline for
males.*

Table 13. Baseline, Week 26 mean (± SD) distances walked and mean
changes in the 6 minute walk distance from baseline to Week 26 by Gender

  ------------ ----------------- ---------------- ------- -------------- -------
               **Timepoint**     **Laronidase**   **n**   **Placebo**    **n**

  **Female**   **Baseline**      327.6 ± 107.7    11      378.1 ± 104.4  12

               **Week 26**       395.2 ± 82.8             368.1 ± 121.1  

               **Change**        67.5                     \- 10.0        

  **Male**     **Baseline**      310.5 ± 157.0    11      354.2 ± 126.9  11

               **Week 26**       282.4 ± 141.6            326.7 ± 139.3  

               **Change**        \- 28.1                  -27.5          
  ------------ ----------------- ---------------- ------- -------------- -------

Figure 6. Mean distance walked in 6 minutes across the study visits
plotted by gender and treatment groups

![](media/image7.wmf){width="4.872916666666667in"
height="4.245833333333334in"}

*Reviewer's comment: Similar to %FVC examined by study visit and gender,
the laronidase-treated males had a lower baseline distance compared to
the other 3 groups. Both the figure and the table clearly show only the
laronidase-treated females contribute to the marginal treatment effect
seen.*

[Analysis by Severity:]{.underline} BioMarin performed the prospectively
planned analysis by severity at baseline of dividing the treatment
groups into a mild subset and more impaired subsets by subdividing based
on baseline walking distance and baseline aggregate median (358 m). This
analysis did not yield any significant differences in the pattern
compared to the study overall.

*Reviewer's comment: A more informative analysis of the mean changes in
the 6 minute walk distance by severity, as seen in Table 14, divides the
45 participating subjects into 4 quartiles by severity at baseline.*

*Table 14* . Mean changes from baseline to week 26 in the 6 minute walk
distance by the quartiles of severity at baseline

+-----------+-------------+----------+------+------------------+----+
| **        | ***Baseline | ***Laron | ***  | ***Placebo***    | *  |
| *Severity | Distance    | idase*** | n*** |                  | ** |
| level***  | range***    |          |      |                  | n* |
|           |             |          |      |                  | ** |
+-----------+-------------+----------+------+------------------+----+
| *least*   | *411 --     | *-5.3 ±  | *3*  | *-19.6 ± 61.4*   | *  |
|           | 591*        | 74.0*    |      |                  | 8* |
| *most*    |             |          |      |                  |    |
+-----------+-------------+----------+------+------------------+----+
|           | *358 --     | *31.1 ±  | *7*  | *-7.7 ± 95.1*    | *  |
|           | 411*        | 64.7*    |      |                  | 4* |
+-----------+-------------+----------+------+------------------+----+
|           | *276.5 --   | *-8.4 ±  | *5*  | *-28.1 ± 83.6*   | *  |
|           | 358*        | 60.9*    |      |                  | 7* |
+-----------+-------------+----------+------+------------------+----+
|           | *14 --      | *39.1 ±  | *7*  | *-9.2 ± 33.1*    | *  |
|           | 276.5*      | 80.1*    |      |                  | 4* |
+-----------+-------------+----------+------+------------------+----+

*No trend related to severity at baseline can be distinguished. This is
unlike the comparable exploratory analysis for FVC.*

*Unlike the examination of distribution of subjects in cross categories
of gender and FVC severity, the distribution of subjects by dual
categorization of gender and Walk distance severity shows less imbalance
in the distribution of numbers of subjects. Thus factors of gender and
severity could be better distinguished on this endpoint. Thus, it is
interesting to note that for this endpoint, gender is still suggested to
have an impact on treatment associated difference, but baseline severity
is not.*

**Post-hoc Exploratory Analysis**

Some effect of the age categories contributed to differences between the
treatment groups, as shown in Table 15.

Table 15. Baseline and Week 26 mean (± SD) 6 minute walk distances and
difference between placebo and laronidase changes by Age Category

  ------------ ------------- -------------- ------------- ---------------- -------------- -------------
  **Age        **Placebo**                                **Laronidase**                  
  category**                                                                              

               **n**         **Baseline**   **Week 26**   **n**            **Baseline**   **Week 26**

  **≤ 12**     10            410.4 ± 119.3  382.9 ± 120.6 12               321.8 ± 121.0  353.6 ± 127.7

                             Difference                                                   
                             between                                                      
                             groups: **59.3                                               
                             meters**                                                     

  **13 -- ≤    8             308.8 ± 112.9  274.6 ± 142.6 3                482.3 ± 111.6  480.7 ± 33.2
  18**                                                                                    

                             Difference                                                   
                             between                                                      
                             groups: **32.5                                               
                             meters**                                                     

  **19 -- ≤    5             371.8 ± 72.3   397.0 ± 78.2  7                244.3 ± 97.8   252.6 ± 84.0
  65**                                                                                    

                             Difference                                                   
                             between                                                      
                             groups: **-                                                  
                             16.9 meters**                                                
  ------------ ------------- -------------- ------------- ---------------- -------------- -------------

*Reviewer's comment: A comparison of the baseline data among the 2
treatment groups in the different age categories reveals more imbalances
between treatment groups within age category than overall for the study.
Although there are few subjects in the older age categories, these data
suggest the possibility that intervention at an earlier age may be more
favorable than at an older age. It is possible, but not proven, that
reduction of accumulated GAG's in heart, lungs and joints be less
resistant to therapy. These data do not suggest even a trend to benefit
in older patients.*

*However, the baseline imbalances for these subsets may preclude drawing
any firm conclusions from this post-hoc exploratory analysis.*

[Analysis by Study Center]{.underline}: Study outcomes were examined by
center. Overall, placebo treated subjects improved in 2 / 5 centers,
whereas laronidase-treated subjects improved in 4 / 5 centers. However,
the numbers are too small to permit drawing any conclusions regarding
center related interactions.

[Analysis of effect of anti-laronidase antibodies]{.underline}: The
anti-laronidase antibody became detectable, using the ELISA assay,
between weeks 4 and 8 for most laronidase-treated subjects (20/22).
Therefore, comparisons between seropositive and seronegative subjects
regarding the change in the 6 minute walk distance were not informative.
There was no correlation between anti-laronidase IgG antibody levels, as
determined by ELISA and the 6 minute walk distance change from baseline
at week 26.

[Analysis by baseline enzyme level]{.underline}: There was no
correlation between the baseline enzyme levels and the baseline 6 minute
walk distance or the change in 6 minute walk distance at week 26 from
baseline in the study as a whole or the 2 treatment groups.

[Analysis by treatment effect in the change of % FVC from
baseline]{.underline}: There is no correlation between the direction and
magnitude of change from baseline to week 26 in % FVC and the 6 minute
walk distance, as seen in figure 7. Subjects who demonstrated
improvement in one of the endpoints cannot be predicted to have
demonstrated improvement in the other. This can be interpreted as
indicating the observed changes in % FVC in the study are not large
enough to have notable impact upon the distance walked in 6 minutes for
these subjects, thus raising uncertainty as to the clinical meaning of
%FVC changes of the size observed in the study.

Figure 7. Baseline to week 26 changes in the % FVC plotted against the
changes in the 6 minute walk distance in individual subjects

![](media/image8.wmf){width="6.6090277777777775in"
height="5.065972222222222in"}

![](media/image9.wmf){width="1.0416666666666666e-2in"
height="1.0416666666666666e-2in"}

Legend: Points shown as filled circles represent laronidase-treated
subjects and points represented as empty circles represent
placebo-treated subjects.

[]{#__RefHeading___Toc27725195 .anchor}Secondary endpoints

#### **[Apnea / Hypopnea Index (AHI) of the sleep study]{.underline}**

**Primary Analysis**

The endpoint used for the analysis of efficacy was the mean AHI change
from baseline to week 26 comparison between the treatment groups by
ANOVA. The AHI is defined as the number of apnea (cessation of airflow
for 10 or more seconds) and hypopnea (50% decrease in airflow per breath
accompanied by arousal or desaturation) events divided by the hours of
sleep, reported as events per hour. Therefore a decrease in the index is
a favorable event. The laronidase-treated subjects experienced an AHI
decrease of 2.9, whereas the placebo-treated subjects had a 0.4 increase
in the AHI. The difference between groups of --3.6 events per hour was
favorable to laronidase but did not reach statistical significance
(p=0.14). The clinical significance of this finding is questionable.

**Exploratory Analysis**

The independent expert who performed the blinded readings of the sleep
studies had noted that a significant number of subjects (18 / 21
placebo-treated and 11 / 20 rhIDU-treated) had normal AHI at baseline
(\< 20), which could have obscured the treatment effect in those with
sleep apnea. He recommended an analysis of the results from subjects
younger than 15 years with AHI scores ≥ 10 and adults with AHI scores ≥
15, based on recently published guidelines (American Academy of Sleep
Medicine Report: Sleep-Related Breathing Disorders in Adults:
Recommendations for Syndrome Definition and Measurement Techniques in
Clinical Research. *Sleep 1999, 22(5):667-689*. [and]{.underline}
American Academy of Pediatrics, Clinical Practice Guideline: Diagnosis
and Management of Childhood Obstructive Sleep Apnea Syndrome.
*Pediatrics 2002 Vol. 109(4):704-714*).

Table 16 shows the data and comparative analysis in the subjects with
clinical sleep apnea/hypopnea at baseline.

Table 16. Baseline and Week 26 mean (± SD) changes in Apnea/Hypopnea
Index (AHI) in Pediatric Subjects with baseline AHI ≥ 10 and Adult
Subjects with baseline AHI ≥ 15

  --------------------- --------------------- --------------- -------------
                        **Statistic**         **Laronidase    **Placebo
                                              (n=11)**        (n=8)**

  **More severe AHI**   **Mean Baseline**     32.1 ± 18.7     26.8 ± 17.6

                        **Mean Week 26**      25.8 ± 18.6     25.8 ± 17.2

                        **Mean Change**       \- 6.3          \- 1.1

                        **Mean Difference**   \- 5.2          

  **Less severe AHI**   **Statistic**         **Laronidase    **Placebo
                                              (n=9)**         (n=11)**

                        **Mean Baseline**     6.2 ± 2.7       6.5 ± 3.6

                        **Mean Week 26**      7.6 ± 5.1       8.0 ± 6.8

                        **Mean Change**       1.3             1.5

                        **Mean Difference**   0.2             
  --------------------- --------------------- --------------- -------------

*Reviewer comment: There is a favorable trend in the decrease of the
number of events during sleep studies among those subjects more severely
affected by sleep apnea / hypopnea that were treated with laronidase
during Study 003. However, this is a small exploratory subset analysis
which does not permit reaching conclusions on the clinical or the
statistical significance of these data. No difference was observed
between treatment groups in the AHI for the subjects with few apnea /
hypopnea events.*

*BioMarin analyzed these subset data with adjusted mean changes using
ANOVA with a change from baseline to week 26 in the placebo-treated
group of 0.3 (n=9) and a change in the laronidase-treated group (n=11)
of -- 6.3, and a difference between groups of -- 9.1 (p= 0.04)*

The expert also recommended analyzing results from all subjects with AHI
≥ 20, a criterion that may warrant nasal CPAP intervention when
apnea-related symptoms are present. The fact that only 3 subjects
allocated to placebo had an AHI ≥ 20 did not allow a meaningful
between-groups subset analysis. However, the 9 laronidase-treated
subjects who had AHI ≥ 20 at baseline demonstrated a decrease of 7.4
events / hour. Among these laronidase-treated subjects 4 reduced the AHI
from ≥ 20 to \< 20.

*Reviewer's comment: It is clinically meaningful to make a comparison
among the subjects that are more severely affected, particularly the
subjects considered for medical intervention. However, due to too few
subjects, no between groups analysis is possible so that no conclusions
can be drawn regarding this subset comparison.*

#### **[Liver volume]{.underline}**

**Primary analysis**

The endpoint used for the analysis of efficacy was the mean liver volume
change from baseline to week 26 ANOVA comparison between the treatment
groups. A statistically significant change occurred favoring the
laronidase-treated group, with a mean 18.9 % decrease (n=22) as compared
to a 1.3 % liver volume increase in the placebo-treated subjects (n=22)
(p=0.001).

**Prospectively Defined Exploratory Analysis**

Of the 14 placebo-treated subjects with hepatomegaly at baseline, 3
subjects (21%) were considered to have reached normal liver volume at
week 26. Of the 18 subjects with hepatomegaly at baseline in the
laronidase-treated group, 13 (72%) had liver volume normalized by week
26.

All clinical sites had shown substantial reductions in liver volume for
their laronidase-treated subjects, and only the University of North
Carolina site had shown a reduction in liver volume among
placebo-treated subjects.

*Reviewer's comment: These results replicate the findings of the Phase 1
study, now in a randomized controlled trial. The findings provide strong
evidence of bioactivity of the enzyme in that it facilitates the
clearance of liver-accumulated heparan and dermatan sulfate. This could
be considered a marker of the activity in MPS I, but the role as a
surrogate for clinically meaningful endpoints is not established. It is
important to notice that liver function is normal in these individuals
with hepatomegaly, and the main negative effect of hepatomegaly, if any,
might relate to the volume burden in respiratory restriction and
discomfort. On the other hand, GAG-related hepatomegaly in MPS I may
carry no clinical implications. There is no correlation between the
laronidase-treated subjects liver volume at baseline and the magnitude
of reduction achieved during the 26 weeks of laronidase treatment.*

#### **[Disability Index from the CHAQ or HAQ]{.underline}**

**Primary Analysis**

The Disability Index was derived from the Children's Health Assessment
Questionnaire (subjects aged 5 --18 years) and the Health Assessment
Questionnaire (subjects aged 19 years and older) and is an overall
summary score from 8 different categories that address dressing and
grooming, arising, eating, walking, hygiene, reach, grip, and common
daily activities. The extent of disability is evaluated using a scale of
0 to 3, with 3 being the worst score. However, these assessment tools
have not been validated in this disease.

The endpoint used for the analysis of efficacy was the mean change from
baseline to week 26 ANOVA comparison of the Disability Index between the
treatment groups. The mean Index for placebo subjects was 1.9 at
baseline and 1.8 at week 26, whereas the mean score for
laronidase-treated subjects was 2.0 at baseline and 1.9 at week 26.
Neither group showed any changes from baseline using these tools.

**Prospectively Defined Exploratory Analysis**

Comparisons of subsets based on severity (above and below the baseline
median value) were inconclusive. There were no significant variations on
these findings among different study centers.

#### **[Shoulder Flexion]{.underline}**

**Primary analysis**

The shoulder flexion variable for this analysis was defined as the mean
of right and left shoulder flexion. The endpoint for the statistical
comparison using ANOVA was the change in flexion degrees from baseline
to week 26 between treatment groups.

The difference between the groups was not statistically significant
(p=0.99), with a mean decrease of 4.6 degrees in the placebo-treated
subjects and a mean decrease of 1.2 degrees in laronidase-treated
subjects.

**Prospectively Defined Exploratory Analysis**

Exclusion of 2 subjects with baseline cervical cord compression did not
change the overall between-groups difference. Analysis subdivided by
baseline joint severity also did not yield any informative results.

*Reviewer's comment: The choice of shoulder flexion as a secondary
endpoint is based on the empiric findings from the Phase 1 study where a
larger change from baseline for this joint than others was observed.
There is no particular medical basis for favoring the shoulder joint. No
conclusion can be drawn from these data on the effect of laronidase
treatment in the shoulder flexion ROM.*

[]{#__RefHeading___Toc27725200 .anchor}Tertiary Endpoints

#### **[Urinary GAG levels]{.underline}**

The endpoint for the statistical comparison using ANOVA was the mean
%change in urinary GAG levels (expressed as µg / mg creatinine) from
baseline to week 26 between the treatment groups. The mean (± SD)
urinary GAG levels increased from 183.3 ± 72.0 at baseline to 250.2 ±
105.1 at week 26 among the placebo-treated subjects, whereas the mean
urinary GAG levels decreased from 188.9 ± 60.9 at baseline to 81.3 ±
26.4 at week 26 among the laronidase-treated subjects. The difference
from placebo in mean % change from baseline to week 26 urinary GAG was
101% (p\<0.001). All laronidase-treated subjects had reductions of their
urinary GAG levels, with substantial decreases seen as early as at week
4 and maintained through week 26. Despite the substantial reduction in
the laronidase group, no subjects in that group reached the normal range
for urinary GAG levels. These results were consistent across study
centers.

*Reviewer's comments: Studies in the canine model of MPS I revealed
decreased vacuolation in glomerular mesangial cells and distal cortical
tubules following treatment with laronidase as a histologic evidence of
GAG clearance. However, patients with MPS I have no demonstrable
impairment in renal function, and therapy with laronidase would
therefore not be expected to affect the kidney function. Therefore,
reduction of urinary GAG levels is a marker of bioactivity, rather that
demonstration of direct clinical benefit, similar to the interpretation
of the reduction in liver volume.*

#### **[Other Tertiary Endpoints]{.underline}**

Other tertiary endpoints of this study provided largely inconclusive
results. No support for a finding of efficacy associated with laronidase
can be drawn from these endpoints. These endpoints are described in
detail in Appendix A.

[]{#__RefHeading___Toc27725203 .anchor}Pharmacokinetic Studies

All subjects randomized at the United Kingdom and the Canadian clinical
sites participated in the pharmacokinetic studies. A total of 23
subjects (12 randomized to laronidase and 11 to placebo) took part and
completed the study. Infusions at weeks 1, 12 and 26 were selected for
the pharmacokinetic studies. Due to the short t~1/2~ observed in the
study relative to the weekly dosing frequency, each infusion was treated
as a single dose for the purpose of pharmacokinetic analysis.

Table 17 shows selected pharmacokinetic parameters assessed in the 12
laronidase-treated subjects for Infusions 1, 12, and 26 representing the
beginning, the middle and the end of the double blind period.

Table 17. Selected pharmacokinetic parameters associated with rhIDU
infusions

  ----------------- ------------ ------------ ------------ ------------ ------------ -------------
  **Parameter**     **Infusion                **Infusion                **Infusion   
                    1**                       12**                      26**         

                    **n**                     **n**                     **N**        

  **Dose (U/Kg)**   12           105 ± 5      12           104 ± 3.3    12           103 ± 3.2

  **Infusion time   12           3.98         12           4.00         12           3.96
  (h)**                                                                              

  **C~max~ (U/mL)** 12           0.197 ± 0.05 11           0.210 ± 0.08 12           0.302 ± 0.09

  **T~max~ (h)**    12           3.93         11           3.83         12           3.92

  **AUC~∞~          10           0.93 ± 0.21  6            0.91 ± 0.44  10           1.19 ± 0.45
  (h·U/mL)**                                                                         

  **CL              10           1.96 ± 0.49  6            2.31 ± 1.13  10           1.68 ± 0.76
  (ml/min/kg)**                                                                      

  **Vz (L/Kg)**     10           0.60 ± 0.17  6            0.31 ± 0.14  10           0.24 ± 0.13

  **Vss (L/Kg)**    10           0.44 ± 0.12  6            0.25 ± 0.08  10           0.22 ± 0.08

  **λ~z~ (h^-1^)**  10           0.20 ± 0.05  6            0.77 ± 1.01  10           0.60 ± 0.52

  **t~1/2~ (h)**    10           3.61 ± 0.89  6            2.02 ± 1.26  10           1.94 ± 1.09

  **MRT (h)**       10           3.84 ± 1.04  6            2.23 ± 1.21  10           2.36 ± 0.83
  ----------------- ------------ ------------ ------------ ------------ ------------ -------------

C~max~=maximum plasma concentration; T~max~= time to maximum plasma
concentration; AUC~∞~=area under the plasma concentration -- time curve
to infinity; CL= total plasma clearance; Vz= mean volume of
distribution; Vss= mean volume of distribution at steady state;
λ~z~=terminal elimination rate constant; t~1/2~=mean elimination half
life; MRT=mean residence time.

Observations and conclusions derived from these studies:

-   differences among the 3 infusions for C~max~, Vz and Vss were
    statistically significant, using Friedman's test (p ≤ 0.015)

-   there was a trend toward an increase in C~max~ over the 26 week
    study

-   CL does not appear to be affected by administration of rhIDU for 26
    weeks

-   there was a 50 % decrease in the Vz and Vss between Infusions 1 and
    12 which remained constant until week 26

-   therefore, increases in C~max~ were related to decreases in Vz

-   decrease in Vz without changes in CL resulted in decrease in t~1/2~
    between Infusions 1 and 12, not statistically significant

-   decrease in Vz may be related to antibody formation between Infusion
    1 and subsequent pharmacokinetic studies. An inverse relationship
    between Vz and antibody levels was seen, causing the speculation
    that antibody-bound laronidase differs from unbound enzyme in its
    distribution, increasing the total body load in plasma and reducing
    the Vz

-   following the infusion the plasma concentration of laronidase
    remained above the concentration for half-maximal saturation of
    uptake into cells, 0.7 nM (0.01 U /mL) for approximately 3 -- 4
    hours.

*Reviewer's comment: These findings were similar to those observed in
canine studies, in which anti-laronidase antibodies resulted in
decreased clearance and decreased tissue uptake of the enzyme. With a
somewhat shorter half life after the first infusions, and a decrease of
enzyme transfer to lysosomes in affected tissues, a concentration to
achieve half maximal saturation of uptake may be sufficient to result in
biologic effects in certain organs and tissues, as seen in liver and
kidney in this study, but not at other organs or tissues, such as
central nervous system, heart, airways and joints. Antibody formation
may alter the uptake distribution of enzyme. Even if the enzyme is not
directly neutralizing, it may still limit activity in some tissues if
antibody-bound enzyme is not distributed into certain tissues. Note that
the data on concentration for half maximal saturation of uptake into
cells is derived not from binding studies in histologic specimens but
from fibroblasts in culture, possibly with different binding
affinities.*

[]{#__RefHeading___Toc27725204 .anchor}Safety

#### **[AE's]{.underline}**

The Safety population consists of the 45 subjects randomized to
treatment, of which 22 received laronidase. AE's were recorded from the
time of signing the consent form until 2 weeks after completion of the
final study procedures. None of the subjects were discontinued from the
study. 6 / 23 subjects in the placebo group and 10 / 22 subjects in the
laronidase group had mild or moderate AE's during the baseline
(pre-randomization) period. During the double blind period all placebo
subjects and 21 / 22 laronidase subjects had ≥ 1 AE's. Drug-related AE's
were reported in 16 / 23 placebo subjects and in 12 / 22 laronidase
subjects. Among the latter, infusion associated reactions (IAR's)
occurred in 11 / 23 placebo subjects and in 7 of 22 laronidase-treated
subjects. IAR's were defined as all drug-related AE's occurring on the
day of infusion, except for those identified by protocol required
assessments prior to the infusion.

All AE's with incidence higher than 30 % in either treatment group
during the double-bind period were summarized as organized by the World
Health Organization Adverse Reaction terminology (WHO-ART) and
identified by the Preferred Term. Headaches, fever and rhinitis were the
most common AE's reported, and these were all more common in the
placebo-treated group (Table 18).

Table 18. Summary of AE's with frequency ≥ 30% during the double blind
period

  ---------------------------------- ------------- ------------- ------- ---------------- -------
  **WHO-ART Body System**            **Preferred   **Placebo**           **Laronidase**   
                                     Term**                                               

                                                   **n**         **%**   **n**            **%**

  Central/Peripheral CNS Disorders   Headache      16            70      11               50

  Body as Whole General Disorders    Fever         14            61      10               45

                                     Pain          7             30      5                23

  Respiratory System Disorders       Rhinitis      10            43      8                36

                                     Coughing      6             26      7                32

                                     URTI          4             17      7                32

  Skin and Appendages Disorders      Rash          5             22      8                36

  Gastro-Intestinal System Disorders Diarrhea      8             35      7                32

                                     Vomiting      9             39      5                23

  Hearing and Vestibular Disorders   Earache       8             35      1                5
  ---------------------------------- ------------- ------------- ------- ---------------- -------

Of the less common AE's (those occurring in ≥ 1 subject), arthropathy
was present in 4 placebo- and 2 laronidase-treated subjects, back pain
in 1 placebo- and 2 laronidase-treated subjects, and fever was reported
in 3 placebo- and one laronidase subject. Two placebo subjects had
diarrhea and abnormal gait, which none of the laronidase-treated
subjects had.

AE's that were possibly, probably or definitely related to study
treatment were reported more often in the placebo-treated group (16 /
23) than in the laronidase-treated group (12 / 22). From these, the most
common were in the laronidase-treated group were flushing (5 / 22) and
rash (3/ 22) whereas headache (6/ 23), flushing (4 / 23), arthropathy (4
/ 23) and fever (3 / 23) were the most commonly reported study treatment
-- related AE's in the placebo group. The number of these study
treatment related AE's was small, and the data showed no trend for any
cluster of AE's in any body system associated with a specific treatment
group.

Two placebo-treated subjects had severe AE's. Subject 50605 had
worsening of the ankle flexion deformity, and subject 60809 had
worsening of psoriatic lesions and increased hepatosplenomegaly. Six
laronidase-treated subjects had severe AE's. Subject 30608 had worsening
of otitis media, subject 60404 had worsening of arthropathy, subject
60908 had increased hepatosplenomegaly, and subjects 61010 and 61111
both had hepatomegaly. Laronidase-treated subjects 30806 and 40606 had
severe AE's that are described below under SAE's.

Eleven of 23 placebo-treated subjects experienced 82 IAR's, whereas 7 /
22 laronidase-treated subjects had 66 IAR's. The most frequently
reported IAR's in the placebo and laronidase treated groups were:
flushing (4 / 23 and 5 / 22), fever (3 / 23 and 1 / 22), headache (2 /
23 and 2 / 22) and rash (2 / 23 and 1/ 22) respectively. The majority of
these IAR's were reported as mild. 5 / 23 placebo-treated subjects and 3
/ 22 laronidase-treated subjects with IAR's required study drug infusion
rate decrease or interruption, or medication with antipyretics and / or
antihistamines.

The protocol called for IgE testing in subjects experiencing moderate or
severe IAR's. 3 subjects with moderate IAR's were tested, being 2 in the
laronidase group and one in the placebo group. The 3 tested negative for
laronidase-specific IgE antibodies.

Data from AE's related to study drug occurring in non-infusion days was
inconclusive.

#### **[Deaths and SAE's]{.underline}**

There were no deaths during the study. One subject had a SAE during the
baseline period of admission to the hospital due to worsening otitis
media. She was later randomized to the laronidase-treated group.

During the double blind period, 3 laronidase-treated subjects had SAE's,
as follows:

-   Subject 10101, a 7 year old female with MPS I H-S, was admitted to
    the hospital with mild abdominal pain after the fourth infusion due
    to constipation that resolved with treatment.

-   Subject 30806, a 43 year old male with MPS I S, had a past medical
    history significant for coronary artery disease with a prior
    myocardial infarction and had cardiac valvular disease at baseline.
    His valvular disease worsened, requiring surgical repair after the
    12^th^ infusion. Post operative course included a cardiac arrest due
    and subsequent pneumonia with sepsis and renal failure. The subject
    was treated with and fully recovered, being discharged from the
    hospital 76 days after his admission.

-   Subject 40606, a 7 year old female with MPS I H-S was hospitalized
    for dehydration after completing 8 infusions. She was diagnosed with
    a partial obstruction of a ventricular shunt, and underwent a shunt
    revision.

#### **[Clinical Laboratory Evaluations]{.underline}**

There were no notable abnormalities in clinical chemistries.

One subject randomized to laronidase had a baseline platelet count of
210,000 / µl and at week 4 108,000 / µl. The platelet count normalized
at Visits 12 and 26.

No other subjects had significant platelet decreases. For the groups
overall, the mean platelet counts in the laronidase group increased from
a baseline of 218 X 10^3^/µL to 253 10^3^/µL (n=22) on study, whereas in
the placebo-treated group the platelet count decreased from a baseline
of 236 X 10^3^/µL to 212 X 10^3^/µL (n=21) at week 26.

No relevant changes in urinalysis were noted in either treatment group.

#### **[Vitals signs and physical findings]{.underline}**

The vital signs assessed at baseline and just prior to the start and
immediately after every infusion were systolic and diastolic blood
pressure, heart rate, respiratory rate, and temperature. No clinically
significant changes were observed.

Data available on changes in physical examinations compared to the
baseline exam do not demonstrate any trends.

#### **[Other findings]{.underline}**

No clinically significant electro- or echocardiographic changes from
baseline were seen in either treatment group.

All subjects underwent brain and cranio-cervical junction MRI at
baseline. All subjects were found to have abnormal findings in the MRI.
The protocol called for a repeat MRI at the end of the study at the
investigator's discretion. 9 placebo-treated subjects and 6
laronidase-treated subjects had a repeat MRI at week 26. From these, the
MRI evaluations of the placebo-treated subjects remained unchanged,
while the 1 /6 laronidase-treated subjects had a shift to a normal MRI
at Week 26.

Given the near universal antibody formation in the laronidase-treated
group, any correlation between serum anti-laronidase IgG antibodies and
adverse events cannot be evaluated in a meaningful way. The effect of
these antibodies on the 2 primary efficacy endpoints, in a qualitative
analysis (i.e. presence or absence of antibodies) was equally
inconclusive.

*Reviewer's comment: An attempt to analyze levels of IgG antibodies as
measured in OD units from the RIP assay with the primary efficacy
outcomes across the 26 weeks of the study among laronidase-treated
subjects failed to demonstrate a significant correlation.*

Complement testing was performed in 3 subjects with moderate IAR's (1
placebo-treated and 2 laronidase-treated subjects) within one hour of
the onset of the IAR. All 3 subjects had negative complement activation
testing.

###### Summary {#summary-1 .Style2}

Study ALID-003 was able to demonstrate a statistically significant
change in the % FVC for the overall laronidase-treated group compared to
placebo, over the 26 weeks of the study. The data, however, does not
demonstrate a progressive improvement in this %FVC over the course of
the study. Rather, the benefit is related to an abrupt improvement from
week 20 to week 26 in the laronidase group, and an abrupt early decrease
in % FVC in the placebo group. The effect is also not uniform across the
enrolled patient population. The treatment effect is driven by an
improvement seen in laronidase-treated females and is more prominent in
the younger subjects. The clinical significance of the observed increase
in %FVC over the study period (5.9%) is marginal, with an absolute
volume mean increase in FVC of 110 mL in the laronidase-treated group,
compared to a 20 mL decrease in the placebo group.

The study has not shown a statistically significant difference in the
other primary endpoint, the 6 minute walk test. Similar to the findings
of subset analyses for the %FVC, a favorable trend is seen, mostly in
females and the younger subjects in the laronidase-treated group.

The clinical significance of these findings is unclear, and
interpretation of these data to support to a claim of efficacy for a
broad range of patients is further confounded by the subset analyses
suggesting non-uniform treatment-associated effects.

This study suggests the possibility that younger and / or patients with
less advanced disease may have some benefits from laronidase treatment,
but this is not conclusively proven. Furthermore, older patients or
subjects with more advanced disease have little evidence of benefit. The
differential effects in the two genders, with the observed better
outcome for both co-primary endpoints in females, cannot be explained on
the basis of known pathophysiology. Females in some clinical trials show
a greater degree of compliance with the treatment and adherence to study
visits, but these potential gender-related effects were not a factor in
this study.

Safety results do not reveal any specific serious or severe adverse
events clearly associated with laronidase. Infusion reactions are
frequent, but were more frequent with the placebo infusion. Infusion
reactions were largely mild and did not pose a difficulty to receiving
laronidase.

Antibody formation against laronidase is nearly universal, whenassessed
both by the quantitative but less specific ELISA assay or the specific
but qualitative RIP assay. Antibody response appears within the first 2
months of treatment. Pharmacokinetic parameters were altered by antibody
formation. The longer term consequences of antibody formation could not
be evaluated in this 6 month study.

[]{#__RefHeading___Toc27725211 .anchor}Study ALID-006

"A Multicenter, Multinational, Open-Label Extension Study of the Safety
and efficacy of recombinant Human Alpha- L-Iduronidase in Patients with
Mucopolysaccharidosis I".

###### Overview {#overview-2 .Style2}

This ongoing study is being conducted under IND 7334. This is an open
label extension of the double blind study ALID-003 reported above solely
for subjects who participated in study ALID-003, and is intended to
provide additional longer term safety and clinical outcome information.
The study period is planned to span 72 weeks or until market approval of
laronidase. The study report included in this review includes 24 weeks
of data on this open label extension study.

###### Protocol {#protocol-2 .Style2}

**Title:** "A Multicenter, Multinational, Open-Label Extension Study of
the Safety and efficacy of recombinant Human Alpha- L-Iduronidase in
Patients with Mucopolysaccharidosis I". Protocol ALID-006-01.

The original protocol was submitted on April 6, 2001

[]{#__RefHeading___Toc27725214 .anchor}Design

This was a multicenter, multinational open label extension study of
subjects with MPS I who had previously participated in the Study
ALID-003 (double-blind 26 week study), for either 72 weeks or until
laronidase obtains marketing approval.

All subjects previously allocated to placebo treatment under ALID-003
were treated with laronidase for this study. The 5 Centers that
participated in Study ALID 003 continued to treat and follow subjects
for all clinical evaluations. However the weekly infusions of laronidase
and safety evaluations could be performed at one of 13 regional
investigational sites closer to the subjects' homes. The principal
investigator for the 5 major sites would still be responsible for the
full evaluation of the subject's medical condition and for all relevant
safety issues, along with the Sponsor Medical Monitor.

[]{#__RefHeading___Toc27725215 .anchor}Objectives

The objective is collection of additional long-term safety data and
clinical status of subjects with laronidase treatment. The interim study
report described here includes safety and clinical status data for the
first 24 weeks of this ongoing study.

[]{#__RefHeading___Toc27725216 .anchor}Eligibility Criteria

**Inclusion criteria:**

-   Must have completed Study ALID-003 and have received at least 21 of
    the 26 consecutive weekly infusions under that study

-   No safety issues that contraindicate participating in this study

-   Females of childbearing potential must have a negative pregnancy
    test at study entry and use adequate contraception during the study.

-   Sexually mature male subjects are advised to use a medically
    acceptable method of contraception during the study

**Exclusion criteria:**

-   Pregnancy or lactation

-   Use of investigational drugs other than those used in Study ALID-003
    within 30 days prior to study enrollment

-   Medical condition, serious intercurrent illness or other
    circumstances affecting compliance with laronidase treatment and
    study evaluations and follow ups.

[]{#__RefHeading___Toc27725217 .anchor}Treatment assignment /
Randomization

In this non-randomized study all eligible subjects were assigned to
active treatment (laronidase).

[]{#__RefHeading___Toc27725218 .anchor}Product Information and
Administration

All subjects received laronidase at a dose of 100 U / kg intravenously
weekly. As in Study 003, laronidase was diluted with between 100 mL to
250 mL of 0.1% human serum albumin in saline through week 24. Infusions
of laronidase after week 24 were prepared without human serum albumin.

Details of the infusion regimen, including pre-treatment, were as done
in Study ALID-003 (see prior study review for details).

Amendment 1 was submitted on February 25, 2002 to remove the 0.1 % human
serum albumin from the product formulation after week 24 of each
subjects participation, due to potential safety concerns related to use
of a human derived product.

[]{#__RefHeading___Toc27725219 .anchor}Evaluations

In general, evaluations were of a similar type as performed in ALID-003.
Evaluations were at study entry (which was also the final study visit of
Study ALID-003) and except as noted, every 12 weeks during this study.

-   Forced Vital Capacity (FVC)

    -   Six-minute walk distance (in meters)

    -   Children's Health Assessment Questionnaire (CHAQ) / Health
        Assessment

Questionnaire (HAQ) (age appropriate tool used)

-   Sleep study (apnea/ hypopnea events and oxygen desaturation) \[Wk
    24, 72\]

-   Liver volume by MRI at Weeks 24 and 72.

-   Urinary Glycosaminoglycans (GAG) .

-   Joint Range of Motion

-   Child Health Questionnaire or SF-36 at Weeks 24, 48 and 72.

-   Resource utilization

-   Standing heights for measurement of growth velocity

-   Visual acuity by standard eye chart testing, ocular pressure,
    corneal clouding, and retina / optic nerve exam at Weeks 24 and 72.

-   EKG and echocardiogram at Weeks 24, 48, and 72.

-   FEV~1~, total lung capacity and diffusing capacity

-   Medical history, VS, and physical examination

-   Clinical Laboratory evaluations

-   Antibody testing at Weeks 4, 8, 12, 16, 20, 24, 36, 48, 60 and 72.
    IgE and complement activation (CH100 or CH50 and C3 or C4
    components) were measured if symptoms of a moderate or severe
    infusion associated reaction are noted.

-   Adverse events

[]{#__RefHeading___Toc27725220 .anchor}Safety Monitoring

An independent Allergic Reaction Review Board (ARRB) was created to
review signs of moderate or severe hypersensitivity and provide guidance
on management of these reactions. The ARRB interacted with the Genzyme
Pharmacovigilance group and infrequently directly with investigators.

[]{#__RefHeading___Toc27725221 .anchor}Endpoints

-   Primary:

    a.  [Percent predicted FVC]{.underline}:

    b.  [6 minute walk]{.underline}:

-   Secondary:

    a.  [Sleep study -- Apnea Hypopnea Index]{.underline}:

    b.  [Liver volume]{.underline}:

    c.  [Shoulder flexion]{.underline}:

    d.  [Disability Index:]{.underline}

-   Tertiary:

    a.  Urinary GAG's

    b.  Total respiratory event index and total sleep time O~2~
        saturation less than 90 % and less than 80 % (derived from the
        sleep study)

    c.  Pain scale (derived from the Children's Health Assessment
        Questionnaire \[CHAQ\] / Health Assessment Questionnaire
        \[HAQ\])

    d.  Joint Range of Motion

    e.  Global assessment based on Child Health Questionnaire or SF-- 36

    f.  Growth Velocity for pre-pubertal subjects

    g.  Visual Acuity, Ophthalmologic exam, tonometry, fundoscopy and
        slit lamp exam

    h.  Cardiac Function Testing by electrocardiogram and echocardiogram
        parameters

    i.  Forced Expiratory Volume in One second (FEV1)

    j.  Total Lung Capacity

    k.  Diffusing Capacity

    l.  Heart rate, respiratory rate and O~2~ saturation

[]{#__RefHeading___Toc27725222 .anchor}Statistical Analysis

The ITT population was used for data analysis. The 2 treatment groups
represented in the report are:

-   laronidase / laronidase group which received laronidase infusions
    for 26 weeks in Study ALID-003 followed by laronidase infusions for
    24 weeks in the present study

-   placebo / laronidase group which received placebo infusions for 26
    weeks in Study ALID-003 followed by laronidase infusions for 24
    weeks in the present study

Missing data from missed study visits or early study dropouts were
imputed with the LOCF method in the primary analysis, except for safety
data, which were not imputed.

[Primary efficacy endpoints]{.underline} (% FVC and 6 minute walk
distance) were analyzed by descriptive statistics and within group t
test. Secondary analyses include the descriptive changes stratified by
center, age, gender, seroconversion status and baseline severity.

[Secondary endpoints]{.underline} were analyzed by the descriptive
changes, without hypothesis testing. Additional analysis of the sleep
study -- AHI endpoint was performed in those subjects with AHI ≥ 20 at
baseline and for pediatric subjects with AHI ≥ 10 or adult subjects with
AHI ≥ 15 at baseline. Liver volume changes were also reported in terms
of shifts in normal / abnormal rates. The disability index and shoulder
flexion were also reported on the basis of baseline severity.

[Tertiary endpoints]{.underline} were analyzed by descriptive changes.

###### Study Conduct {#study-conduct-2 .Style2}

[]{#__RefHeading___Toc27725224 .anchor}Database Integrity

Genzyme Corporation had responsibility as clinical monitor and as CRO
for data collection, completeness and accuracy verification, and
analysis. All data editing was complete and data-related decisions
finalized made prior to locking the study-interim database.

[]{#__RefHeading___Toc27725225 .anchor}Protocol Violations

Subject 30309 in the placebo/laronidase group had a heart transplant,
violating exclusion criteria; Subject 30806 in the laronidase/laronidase
group violated inclusion criteria by failing to receive at least 21 of
the 26 infusions in the double blind study. These violations do not
impair interpreting the data resulting from this study.

[]{#__RefHeading___Toc27725226 .anchor}FDA site inspection findings

The findings of site inspections are pending at the time of writing this
review.

###### Results {#results-2 .Style2}

[]{#__RefHeading___Toc27725228 .anchor}Subject disposition

The study started on May 29, 2001 and is still ongoing. The same 23
subjects allocated to the placebo treatment arm and the 22 subjects
allocated to laronidase treatment are participating in Study ALID-006.
The only treatment all subjects received was laronidase at a dose of 100
U / kg IV weekly. The 2 groups referred to in this study report are:
laronidase / laronidase and placebo / laronidase, for the subjects
continuing to receive weekly infusions of laronidase and for those
switched to laronidase, respectively.

[]{#__RefHeading___Toc27725229 .anchor}Study entry characteristics

The term "study entry" is used to mean the time of the last infusion in
ALID-003. At study entry, the primary clinical characteristics were as
shown in the Table 19.

Table 19. Entry characteristics of primary endpoints in the treatment
groups

+----------------------------+--------------------+--------------------+
| **Entry Characteristics**  | **Pl               | **Laron            |
|                            | acebo/laronidase** | idase/laronidase** |
|                            |                    |                    |
|                            | **n = 23**         | **n = 22**         |
+----------------------------+--------------------+--------------------+
| \% Predicted FVC (mean ±   | 53.6 ± 14.2        | 53.7 ± 18.6        |
| SD)                        |                    |                    |
+----------------------------+--------------------+--------------------+
| 6 min. walk distance (m)   | 348.3 ± 128.9      | 338.8 ± 127.1      |
| (mean ± SD)                |                    |                    |
+----------------------------+--------------------+--------------------+

[]{#__RefHeading___Toc27725230 .anchor}Study drug exposure

The mean number of infusions in the placebo/laronidase treatment group
was 21.6 and in the laronidase/laronidase group was 21.8, out of a
maximum of 24 infusions. The mean number of days in the study was 157.5
days in the placebo/laronidase group and 158.9 days in the
laronidase/laronidase group. Subjects 10303, 60809, 30705 and 30806
missed 7, 9, 7 and 8 infusions, respectively.

[]{#__RefHeading___Toc27725231 .anchor}Primary endpoints

Note: For the purpose of the review of this study report and to keep
nomenclature consistent with the sponsor's designations,
[baseline]{.underline} is defined as the last measurement prior to
randomization in the Study ALID-003 and [study entry]{.underline} is
defined as the last measurement obtained in study ALID-003.

#### **[Percent Predicted Forced Vital Capacity (% FVC)]{.underline}**

**Primary Analysis**

From entry to week 24 the mean change in % FVC for the
laronidase/laronidase group was a 0.6 % increase. The placebo/laronidase
group had a 0.6 % decrease in % FVC from study entry to week 24.

Table 20 shows the mean (± SD) changes in % FVC from baseline to week
24.

Table 20. Mean (± SD) changes in % FVC from baseline to week 24

  ----------------------------- ------------------------- ----------------------
                                **Laronidase/laronidase   **Placebo/laronidase
                                (n=22)**                  (n=23)**

  **Baseline**                  48.4 ± 14.8               54.2 ± 16.0

  **Entry**                     53.7 ± 18.6               53.6 ± 14.2

  **Week 24**                   54.3 ± 19.6               53.1 ± 16.2

  **Change from baseline to     5.3                       \- 0.6
  week 26 of Study 003**                                  

  **Change from entry into      0.6                       \- 0.6
  Study 006 to week 24**                                  
  ----------------------------- ------------------------- ----------------------

*Reviewer's comment: The response in both treatment groups is notable
given the relatively favorable results observed for this endpoint in the
double blind controlled study. After an initial improvement in the mean
% FVC for the laronidase-treated group in 26 weeks of study ALID-003, no
additional improvement was obtained after another 24 weeks with the same
treatment.*

*Even more significant is the fact that after receiving 24 weeks of
laronidase treatment the prior-placebo subjects had their % FVC
unchanged. The sponsor proposed to interpret these data as not creating
uncertainty regarding the efficacy of laronidase based on the fact that
the placebo group had less severe restriction at baseline, or that
missed infusions and seasonal changes contributed to these findings.
However Study 003 suggests that subjects with less severe lung
restrictions were the ones that had a better chance of improvement under
treatment with laronidase, contrary to the sponsor's interpretation of
Study 006 data. Furthermore, there are no data to support the proposal
that seasonal changes or missed infusions in the placebo-laronidase
group contributed to the lack of change of %FVC over the 24 weeks of
laronidase treatment in the placebo-laronidase group.*

*Reviewer's note: The FVC data include results obtained at study entry
from 5 subjects in Clinical Site 4 who had incorrect data entered as
described for Study ALID-003 (adult pulmonary laboratory assessments
instead of the pediatric pulmonary lab). Preliminary assessment of the
corrected data are reported to not substantially change the results.
This note applies to all FVC analyses for this study.*

**Exploratory Analysis**

[Analysis by Study Visit]{.underline}: Figure 8 shows changes in % FVC
from baseline (calculated based on current height at the time of the
study visits when the endpoint was assessed) through week 26 in the
double blind study ALID-003 and through week 24 of the extension study
ALID-006.

Figure 8. % FVC in Study ALID-006.

![](media/image10.wmf){width="6.834027777777778in"
height="5.279861111111111in"}

*Reviewer's comment: The figure was amplified in the range 40 to 60 %
where the subtle changes in predicted FVC were observed (Figure 9)*

Figure 9. Mean % FVC (calculated using baseline height) Study 006

![](media/image11.wmf){width="6.834027777777778in"
height="5.290972222222222in"}

*Reviewer's comment: This figure illustrates the absence of % FVC change
in the groups during Study 006. The analysis of FVC based as pulmonary
volumes (see below) shows no change during ALID-006 as well.*

[Analysis by Study Center]{.underline}: Mean %FVC change to week 24
within each center ranged from -2.6 to 3.0 in the laronidase/laronidase
group, and -4.0 to 1.4 in the placebo/laronidase group. With these small
numbers of subjects per site, no conclusions regarding any site-related
differences are possible.

[Analysis by Gender]{.underline}: Table 21 shows the mean changes for
males and females in both treatment groups

Table 21. Mean changes (± SD) from entry to week 24 in % FVC in Study
ALID-006 by Gender

  ----------------- --------------------------- ------- ------------------------ -------
  **Gender**        **Laronidase/laronidase**   **n**   **Placebo/laronidase**   **n**

  **Females**       1.7 ± 9.45                  11      -1.6 ± 3.7               12

  **Males**         \- 0.5 ± 7.2                11      0.5 ± 6.0                11
  ----------------- --------------------------- ------- ------------------------ -------

*Reviewer's comment: These changes are relatively small. It is
interesting to note that the laronidase-treated females in the double
blind study exhibited the largest improvement, there was still a
suggestion of a small additional improvement during the additional 24
weeks of laronidase treatment in these same females. On the other hand,
placebo-treated females in the double blind study did not realize the
same apparent benefit in % FVC when they converted to laronidase
treatment in the extension study, and in fact a further, small decline
is suggested. Males were largely unchanged in their % FVC during Study
006. Therefore, again the evidence for an improvement following
treatment with laronidase in % FVC derives entirely from the 11 females
initially assigned to laronidase. Neither the 12 females subsequently
treated with laronidase nor either set of males has demonstrated
improvement with laronidase.*

*The stability of % FVC over the Study 006 period is impossible to
interpret due to the absence of a control group.*

[Analysis by Age group]{.underline}: Table 22 shows the changes by age
category in the % FVC

Table 22. Mean changes (± SD) from entry to week 24 in % FVC in Study
ALID-006 by Age Category

  ----------------- --------------------------- ------- ------------------------ -------
  **Age category**  **Laronidase/laronidase**   **n**   **Placebo/laronidase**   **n**

  **≤ 12**          2.8 ± 10.5                  12      0.5 ± 5.1                10

  **13 -- 18**      0.5 ± 4.5                   3       \- 2.0 ± 6.1             8

  **19 -- 65**      -3.1 ± 2.9                  7       \- 0.3 ± 2.2             5
  ----------------- --------------------------- ------- ------------------------ -------

*Reviewer's comment: The effect of laronidase in children younger than
12 years during the double blind study was clearly greater (8%) than
that seen in other subset analysis performed on these % FVC data.
However, the same finding could not be reproduced in the 10 children
initially treated with placebo who were converted to laronidase for a 24
week period (0.5 % increase in mean % FVC). The reasons for this are not
apparent. No conclusions regarding any favorable effects can be formed
from these data.*

[Analysis by severity]{.underline}. Table 23 shows the change in % FVC
from baseline in Study ALID-003 to week 24 of Study ALID-006 based on
quartiles of severity at baseline.

Table 23. Change in % FVC from baseline to week 24 by severity of % FVC
at baseline

+----------+------------+------------------+---+----------------+---+
| **       | **range %  | **Laronid        | * | **Placeb       | * |
| Severity | FVC**      | ase/laronidase** | * | o/laronidase** | * |
| level**  |            |                  | n |                | n |
|          |            |                  | * |                | * |
|          |            |                  | * |                | * |
+----------+------------+------------------+---+----------------+---+
| least    | 65.4 --    | 0.6 ± 2.9        | 4 | 0.4 ± 4.4      | 7 |
|          | 77.4       |                  |   |                |   |
| most     |            |                  |   |                |   |
+----------+------------+------------------+---+----------------+---+
|          | 51.9 --    | 2.9 ± 6.0        | 6 | 1.3 ± 3.9      | 6 |
|          | 65.4       |                  |   |                |   |
+----------+------------+------------------+---+----------------+---+
|          | 41.6 --    | 0.7 ± 12.3       | 6 | -3.0 ± 4.1     | 5 |
|          | 51.9       |                  |   |                |   |
+----------+------------+------------------+---+----------------+---+
|          | 15.5 --    | -1.7 ± 9.1       | 6 | -1.7 ± 7.4     | 5 |
|          | 41.6       |                  |   |                |   |
+----------+------------+------------------+---+----------------+---+

*Reviewer's comment: No conclusion can be formed from the % FVC change
according to quartiles of severity at baseline.*

[Analysis of effect of anti-laronidase antibodies]{.underline}

20 of the 22 laronidase-treated subjects in the double blind study
seroconverted as assessed by the RIP assay. An additional
laronidase-treated subject seroconverted during the open label extension
study. However, 2 of the laronidase-treated subjects became seronegative
at different timepoints during the open label study. The vast majority
of laronidase-treated subjects that developed anti-laronidase antibodies
remained seropositive for the duration of the study. From the 23
placebo-treated subjects in the double blind study, 21 seroconverted
during the open label extension study, typically between 4 and 8 weeks
of laronidase treatment and remained seropositive for the 24 weeks of
Study 006. In view of the high prevalence of anti-laronidase antibody
positive subjects in both treatment groups, no meaningful comparisons
can be made for the changes in % FVC during the extension study
regarding the effects of antibody formation.

[Analysis by Forced Vital Capacity as absolute volume:]{.underline} The
placebo-laronidase group had a mean (± SD) of 1.31 (± 0.52) L at Study
006 entry and 1.30 (± 0.54) L by week 24. The laronidase-laronidase
group had a mean (± SD) of 1.26 (± 0.59) L at Study 006 entry and 1.25
(± 0.57) L by week 24. No change from baseline within each group and no
difference between groups could be appreciated.

*Reviewer's comment: These data parallel the observed effect of
laronidase on the primary endpoint of % predicted FVC for the two
treatment groups during the open label extension study (if calculated
relative to baseline height). The results reveal the raw pulmonary
volume data uninfluenced by factors age and height factors used to
calculate the predicted FVC. The absence of improvement with laronidase
stand in contrast with the small gains in pulmonary volumes observed
during the double blind study 003 by the laronidase-treated group.*

#### **[6 Minute Walk Distance]{.underline}**

**Primary Analysis**

From entry to week 24 the mean change in the 6 minute walk distance for
the laronidase/laronidase group was an increase of 23.2 meters (Table
24), approximately the same distance gained during the 26 weeks of the
double blind study (19.7 meters). The placebo/laronidase group
demonstrated a similar change of an increase of 23.8 meters from study
entry to week 24. This represents a reversal of the 18.4 meters decrease
observed in this group from baseline to week 26 of the double blind
study.

Table 24. Mean (± SD) changes in the 6 minute walk distance (meters)
from baseline to week 24

  ----------------------------- ------------------------- ----------------------
                                **Laronidase/laronidase   **Placebo/laronidase
                                (n=22)**                  (n=23)**

  **Baseline**                  319.0 ± 131.4             367.6 ± 116.2

  **Entry**                     338.8 ± 127.1             352.7 ± 130.1

  **Week 24**                   362.0 ± 124.4             376.5 ± 116.8

  **Change from baseline to     19.7                      \- 18.4
  week 26 of Study 003**                                  

  **Change from entry into      23.1                      23.8
  Study 006 to week 24**                                  
  ----------------------------- ------------------------- ----------------------

**Prospectively defined exploratory analysis**

[Analysis by Study Visit]{.underline}: Both treatment groups increased
their mean distance walked approximately to the same degree, although
the placebo/laronidase group appeared to have most of the increase in
the first 12 weeks of the extension study and the laronidase/laronidase
group had a more substantial increase between weeks 12 and 24 of the
extension study (Figure 10)

Figure 10 shows the mean changes (± SEM) in the 6 minute walk distance
across all timepoints in Study ALID-003 and ALID-006

![](media/image12.wmf){width="5.501388888888889in"
height="4.039583333333334in"}

[Analysis by Study Center]{.underline}: Variations among the within
center means within treatment group were substantial, ranging from a
decline in mean distance by 18 m to an increase in distance by 64 m. No
conclusions can be drawn due to the small sample sizes. Most centers
observed some increase in distance walked in each group.

Table 25. Mean changes (± SD) from entry to week 24 in 6 minute walk
distance in Study ALID-006 by Clinical Site

  ----------------- --------------------------- ------- ------------------------ -------
                    **Laronidase/laronidase**   **n**   **Placebo/laronidase**   **n**

  **1. United       17.7 ± 19.0                 6       58.0 ± 84.5              5
  Kingdom**                                                                      

  **3. Germany**    5.3 ± 11.7                  4       18.2 ± 28.8              5

  **4. North        17.7 ± 44.1                 3       -10.0 ± 34.4             3
  Carolina**                                                                     

  **5. New York**   -17.7 ± 32.0                3       -14.0 ± 66.1             4

  **6. Canada**     63.8 ± 46.0                 6       45.6 ± 46.7              5
  ----------------- --------------------------- ------- ------------------------ -------

*Reviewer's comment: It is interesting to note that the 6 subjects
originally randomized to Laronidase in the Canadian site had a mean
change --17 m in ALID-003 and showed the greatest gain in distance in
ALID-006, +64 m. The degree to which this illustrates the intra-subject
variability over time for this test, the bias related to open label
treatment in ALID-006, or a true 6 month delay in benefit cannot be
determined. Of similar note, the apparent decline in walk distance of
-18m overall in Study ALID-003 was related to the two large
by-site-declines of -54 and -45 m observed in the UK and Canada sites
respectively. These declines were almost exactly reversed during
ALID-006, by the two largest by-site-improvements in the
placebo/laronidase group, so that the placebo/laronidase subjects in
these two sites completed ALID-006 with the same walking capacity of 1
year earlier, at the start of ALID-003. Again, there is no ability to
distinguish between an illustration of intra-subject variability, bias
related to open label treatment, and true treatment effect.*

[Analysis by Gender]{.underline}: Table 26 shows the mean changes in
each site for males and females in both treatment groups

Table 26. Mean changes (± SD) from entry to week 24 in the distance
walked in 6 minutes in Study ALID-006 by Gender

  ----------------- --------------------------- ------- ------------------------ -------
  **Gender**        **Laronidase/laronidase**   **n**   **Placebo/laronidase**   **n**

  **Females**       9.2 ± 25.9                  11      29.3 ± 64.2              12

  **Males**         37.2 ± 49.2                 11      17.1 ± 55.1              10
  ----------------- --------------------------- ------- ------------------------ -------

*Reviewer's comment: The result here is different than that of Study
003, in which males in both treatment groups experienced a decrease of
approximately 28 meters, whereas laronidase-treated females had a
remarkable mean increase of 67.5 meters. Here there are relatively small
increases in distance walked for all groups. The meaning of this
observation cannot be determined in the absence of a control group.*

[Analysis by gender and study visit]{.underline}: Figure 11 shows the
variation of the 6 minute walk distance by gender and treatment groups
across the study visits.

![](media/image13.wmf){width="5.338888888888889in"
height="3.5388888888888888in"}

*Reviewer's comment: Unlike the data obtained in the double blind study,
in which females treated with laronidase drove the treatment effect, the
open label extension study shows no major changes for a particular
gender in a particular group.*

[Analysis by age group]{.underline}

[Table 27]{.underline} shows the effect of 24 weeks of laronidase in the
2 treatment groups of Study ALID-006 by age category.

Table 27. Mean changes (± SD) from entry to week 24 in 6 minute walk
distance in Study ALID-006 by Age Category

  ----------------- --------------------------- ------- ------------------------ -------
  **Age category**  **Laronidase/laronidase**   **n**   **Placebo/laronidase**   **n**

  **≤ 12**          28.3 ± 37.8                 12      24.3 ± 54.9              10

  **13 -- ≤ 18**    8.0 ± 22.3                  3       25.7 ± 83.7              7

  **19 -- ≤ 65**    21.0 ± 53.9                 7       20.0 ± 32.8              5
  ----------------- --------------------------- ------- ------------------------ -------

No conclusion can be drawn from the 6 minute walk distance changes
according to age group in Study 006. These results are unlike Study 003,
in which a greater effect was seen in the younger subset.

[Analysis by severity]{.underline}

[Table 28]{.underline} shows the mean changes in the 6 minute walk
distance for the 2 treatment groups by quartiles of severity at
baseline.

Table 28. Mean changes (± SD) from entry in Study ALID-006 in the 6
minute walk distance at week 24 by the quartiles of severity at Study
ALID-003 baseline

+----------+------------+------------------+---+----------------+---+
| **       | **Distance | **Laronid        | * | **Placeb       | * |
| Severity | range**    | ase/laronidase** | * | o/laronidase** | * |
| level**  |            |                  | n |                | n |
|          |            |                  | * |                | * |
|          |            |                  | * |                | * |
+----------+------------+------------------+---+----------------+---+
| least    | 411 -- 591 | 5.3 ± 26.8       | 3 | 14.5 ± 40.4    | 8 |
|          |            |                  |   |                |   |
| most     |            |                  |   |                |   |
+----------+------------+------------------+---+----------------+---+
|          | 358 -- 411 | 35.0 ± 47.4      | 7 | 35.2 ± 78.0    | 4 |
+----------+------------+------------------+---+----------------+---+
|          | 276.5 --   | 29.4 ± 52.8      | 5 | 35.0 ± 89.8    | 6 |
|          | 358        |                  |   |                |   |
+----------+------------+------------------+---+----------------+---+
|          | 14 --      | 18.9 ± 34.0      | 7 | 27.1 ± 44.9    | 4 |
|          | 276.5      |                  |   |                |   |
+----------+------------+------------------+---+----------------+---+

*Reviewer's comments: No trends are apparent in any category of severity
at baseline.*

[Analysis by treatment effect in the change of % FVC from
baseline]{.underline}: There is no correlation between the direction and
magnitude of change from baseline to the end of Study ALID-006 between
the data observed for % FVC and for the 6 minute walk distance (Figure
12). This again suggests that the changes observed in FVC in these
studies are not large enough to be a dominant influence on the walking
capacity as tested in the 6 minute walk test.

![](media/image14.wmf){width="5.625in" height="4.322916666666667in"}

![](media/image9.wmf){width="1.0416666666666666e-2in"
height="1.0416666666666666e-2in"}

Legend: Points shown as filled circles represent laronidase-treated
subjects and points represented as empty circles represent
placebo-treated subjects.

[Analysis of effect of anti-laronidase antibodies]{.underline}

Table 29 shows the mean changes from entry into study ALID-006 to week
24 in the 6 minute walk distance for the 2 treatment groups in the
anti-laronidase antibody positive groups, and individual values of 6
minute walk distance change in those few subjects that remained or
became seronegative by week 24.

  ---------------- --------------------------- ------- ------------------------ -------
  **Antibody       **Laronidase/laronidase**   **n**   **Placebo/laronidase**   **n**
  status**                                                                      

  **Positive**     26.6 ± 43.1                 19      22.7 ± 62.1              20

  **Negative**     -5, -2 , 11                 3       31, 39                   2
  ---------------- --------------------------- ------- ------------------------ -------

Duration of anti-laronidase antibodies as measured by RIP in subjects
who seroconverted during the double blind study or during the open label
extension did not correlate with changes in 6 minute walk distance in
those timepoints corresponding to periods of seropositivity or
seronegativity. Because most subjects were antibody positive and
remained so there is little ability to discern whether or not antibody
formation is limiting clinical changes associated with laronidase.

[]{#__RefHeading___Toc27725234 .anchor}Secondary endpoints

#### **[Apnea Hypopnea Index]{.underline}**

**Primary analysis**

Only small changes were observed during ALID-006. During study 006 the
placebo/laronidase group experienced a change similar as the laronidase
group had experienced in ALID-003. However, the laronidase treated group
did not experience any further decline in AHI (Table 30). No statistical
or clinical conclusions can be drawn from these data.

Table 30. Mean changes (± SD) in the Apnea/hypopnea Index from baseline
of Study 003 through Week 24 of Study 006

  ----------------------- --------------------------- ------- ---------------------- -------
                          **Laronidase/laronidase**   **n**   **Placebo/laronidase   **N**
                                                              (n=23)**               

  **Baseline**            21.4 ± 19.1                 19      12.8 ± 11.2            19

  **Entry**               18.2 ± 17.0                 19      14.3 ± 13.8            17

  **Week 24**             19.4 ± 21.6                 19      10.6 ± 7.6             19

  **Change from baseline  \- 2.9                              0.4                    
  to entry**                                                                         

  **Change from entry to  1.2                                 \- 3.5                 
  week 24**                                                                          
  ----------------------- --------------------------- ------- ---------------------- -------

**Exploratory Analysis**

[Sleep apnea at baseline]{.underline}: The sponsor prospectively defined
an analysis of the subjects who had sleep apnea at baseline, pre-defined
as AHI scores ≥ 10 for children under 15 years of age and AHI scores ≥
15 for adult (older then 15 years of age) subjects. For this analysis,
11 subjects were identified in the laronidase/laronidase group and 9
subjects were identified in the placebo/laronidase group. In addition,
the sponsor excluded subject 30806 from this analysis, with the
rationale that he had severe sleep apnea with scores ranging from 60 to
100, and variations of the AHI scores within this range are not
clinically meaningful, as they likely represent an artifact in the
recording of these events.

The data analysis in these subsets showed that subjects in the
placebo/laronidase group had a mean reduction of 9.2 events per hour
from entry into study 006 to week 24, after the mean increase of 2.5
events / hour during study 003. Subjects in the laronidase/laronidase
group had an increase in the mean AHI score of 0.5 from study 006 entry
to week 24, generally maintaining the improvement in AHI during study
003 (decrease of 6.3 events per hour). Among the subjects with few
apnea/hypopnea events at baseline, no changes from baseline and no
differences between the 2 groups were seen.

*Reviewer's comment: The rationale of studying the effect of laronidase
on the AHI scores of subjects with sleep apnea at baseline is
reasonable, and potentially has clinical meaning. However, exclusion of
subject 30806 from the 11 subjects in the laronidase/laronidase group
may not be as appropriate. While subject 30806 is clearly an outlier,
with a baseline index of 78.9, he was included and contributed to the
initial drop in the mean AHI score during the double blind study 003
(-9.1 from baseline to week 26 for this subject) and he was not excluded
then. His AHI score increased from 69.8 at study 006 entry to 97.2 (a
score increase of 27.4, the highest in the group) and is being excluded
only for this analysis. Had he been included in the analysis, the
laronidase/laronidase group with sleep apnea at baseline would have a
mean increase of 2.9, rather than 0.5, events per hour. This would
entirely eliminate the group decline in events seen in ALID-003.
Consequently, it is further difficult to draw any conclusions regarding
effects on AHI based on the results in Study 006.*

*A separate analysis was conducted to study the effect of laronidase in
subjects with baseline AHI ≥ 20. In the laronidase/laronidase subset
with baseline AHI score ≥ 20, the mean AHI (n=9) increased from 28.8 to
31.2 ( or a decrease from 23.6 to 23.0 if subject 30806 is excluded).
Only 2 subjects in the placebo / laronidase group had AHI ≥ 20 at
baseline, and these 2 subjects had decreases in AHI scores of 18.9 and
18.4 events per hour.*

[Analysis by gender]{.underline}: Table 31 shows the effect of
laronidase (mean ± SD) on the Apnea / Hypopnea Index in the 2 treatment
groups by gender

  --------------------------- ------------ -------------- ------- ----------- ------- ---------- -------
  **Treatment Group**         **Gender**   **Baseline**   **n**   **Entry**   **n**   **Week     **n**
                                                                                      24**       

  **Laronidase/laronidase**   Male         28.8 ± 22.2    10      26.3 ± 19.9 10      25.5 ±     11
                                                                                      26.4       

                              Female       12.1 ± 10.6    10      8.9 ± 5.4   10      12.9 ±     10
                                                                                      11.6       

  **Placebo/laronidase**      Male         22.7 ± 20.4    9       23.1 ± 19.3 8       13.0 ±     8
                                                                                      10.4       

                              Female       8.7 ± 4.9      12      9.9 ± 7.7   11      8.8 ± 4.6  11
  --------------------------- ------------ -------------- ------- ----------- ------- ---------- -------

*Reviewer's comment: Males in both treatment groups had worse AHI scores
at baseline as compared to females in both groups. The difference
between the genders is greater than the suggested possible treatment
effect of laronidase. Nonetheless, in study 003, both male and female
subjects in the laronidase-treated groups had similar small improvement
in AHI scores. In the same study, males and females receiving placebo
had similar small degrees of worsening of AHI scores. In the open label
extension study 006 most of the improvement seen in the overall
placebo/laronidase group is driven by the males in the group with a
large decline in AHI out of line with any other subgroup changes seen.
These data are difficult to interpret regarding a treatment effect in
the absence of a control group.*

#### **[Liver volume]{.underline}**

**Primary analysis**

During Study 006 the laronidase/laronidase group was essentially
unchanged in liver volume, while the placebo/laronidase group had a
decline that was not as large that had been observed with the laronidase
group of Study 003 (Table 32).

Table 32. Mean (± SD) liver volumes (cc) and mean percentage changes (%)
in liver volumes during Study 003 and Study 006 by treatment group

  --------------- --------------- --------------------------- ------- ------------------------ -------
  **Parameter**   **Timepoint**   **Laronidase/laronidase**   **n**   **Placebo/laronidase**   **n**

  **Liver Volume  **Baseline**    1211.2 ± 297.6              20      1358.0 ± 301.4           18
  (cc)**                                                                                       

                  **Entry**       998.8 ± 331.5               20      1300.6 ± 278.3           18

                  **Week 24**     945.9 ± 286.4               20      1114.1 ± 256.5           18

  **% Change**    **Baseline to   \- 18.9 ± 19.4              22      1.3 ± 19.2               22
                  Entry**                                                                      

                  **Entry to week \- 3.6 ± 16.4               20      -12.6 ± 19.7             18
                  24**                                                                         
  --------------- --------------- --------------------------- ------- ------------------------ -------

*Reviewer's comment: In Study 003, of the 18 laronidase-treated subjects
with hepatomegaly at baseline, 13 achieved liver volumes in the normal
range during Study 003 (versus 3 of 14 in the placebo group). During
study 006, 2 more subjects with hepatomegaly continuing laronidase
treatment had normalization of liver volumes. In Study 006, only 5 of
the 11 placebo/laronidase subjects with hepatomegaly at study entry had
their liver volume normalized.*

*Similar to the findings of liver volume reduction seen for the Phase 1
study, most of the reduction in volume for the laronidase-treated group
took place during the first 6 months of therapy.*

#### **[Shoulder flexion]{.underline}**

**Primary analysis**

Both treatment groups experienced similar degrees of very mild
improvements during the open label extension study 006 (Table 33),
although larger than that seen in ALID-003.

Table 33. Mean (± SD) shoulder flexion range of motion (degrees) and
changes during Study 003 and Study 006 by treatment group

  ------------------- --------------------------- ------- ------------------------ -------
  **Timepoint**       **Laronidase/laronidase**   **n**   **Placebo/laronidase**   **n**

  **Baseline**        96.1 ± 30.2                 19      89.8 ± 24.0              23

  **Entry**           88.9 ± 37.7                 22      85.2 ± 32.7              23

  **Week 24**         94.7 ± 26.1                 22      91.5 ± 24.1              23

  **Baseline to       \- 1.5 ± 30.4                       -4.9 ± 27.6              
  Entry**                                                                          

  **Entry to week     5.8 ± 21.2                          6.3 ± 20.8               
  24**                                                                             
  ------------------- --------------------------- ------- ------------------------ -------

*Reviewer's comment: These data do not support a clinically meaningful
treatment effect on shoulder flexion range of motion. The impact of
unblinding during study 006 may have contributed to the 6 degrees
improvement seen in both treatment groups.*

Analysis by severity (shoulder flexion range of motion above and below
the median for the overall group at baseline of study 003) was also
inconclusive.

#### **[Disability Index]{.underline}**

**Primary Analysis**

The CHAQ/ HAQ Disability Index evaluates the extent of disability on a
scale of 0 to 3, with 3 being the worst score.

Table 34 shows the mean (± SD) shoulder flexion range of motion
(degrees) and changes during Study 003 and Study 006 by treatment group

  ------------------- --------------------------- ------- ------------------------ -------
  **Timepoint**       **Laronidase/laronidase**   **n**   **Placebo/laronidase**   **N**

  **Baseline**        2.0 ± 0.49                  21      1.9 ± 0.6                22

  **Entry**           1.9 ± 0.58                  21      1.8 ± 0.73               22

  **Week 24**         1.7 ± 0.54                  21      1.6 ± 0.8                22

  **Baseline to       \- 0.1                              \- 0.1                   
  Entry**                                                                          

  **Entry to week     -0.2                                \- 0.2                   
  24**                                                                             
  ------------------- --------------------------- ------- ------------------------ -------

These changes through 50 weeks of study (combined Studies 003 and 006)
were very small, similar for both treatment groups, and do not support a
conclusion of a beneficial treatment effect.

[]{#__RefHeading___Toc27725239 .anchor}Tertiary endpoints

#### **[Urinary GAG's]{.underline}**

After the 54 % reduction in urinary GAG concentration noted in the
laronidase-treated group during Study 003, an additional 20 % reduction
occurred in this group during the open label Study 006. The
placebo-treated group had a mean 47 % increase in urinary GAG
concentration during Study 003, and had a 68.9% mean reduction when
switched to laronidase treatment during the open label extension 006.

At baseline in Study 003 and at entry into Study 006 all subjects in
both treatment groups had abnormal urinary GAG concentrations. At week
24 of Study 006 most subjects still had abnormal urinary GAG excretion
although, 6 of the 22 subjects in the laronidase/laronidase group had
normal GAG levels, and 3 of the 23 subjects in the placebo/laronidase
group had normal GAG levels.

#### **[Other Tertiary Endpoints]{.underline}**

Analyses of other tertiary clinical endpoints do not support any clear
conclusions regarding the activity of laronidase treatment in these
subjects. Details of these analyses are included in Appendix B.

[]{#__RefHeading___Toc27725242 .anchor}Safety

#### **[AE's]{.underline}**

This study report covers the first 24 weeks of the ongoing Study 006.
AE's in study 006 are defined as having begun at the time of enrollment
in the Open Label Study through Week 24, or that began during the Double
Blind Study (003) and worsened during the 24 weeks of Open Label
Extension.

All subjects in both treatment groups experienced at least 1 AE during
the study. One subject in the placebo/laronidase discontinued treatment
due to a SAE, and one subject chose to discontinue treatment at week 24.

Three subjects among the placebo/laronidase group reported severe AE's
(one of respiratory distress, one of chronic bronchitis, tracheitis, and
myocarditis seen at autopsy and one with chocking), and 1
laronidase/laronidase subject reported a severe AE (abnormal vision).

Possibly, probably or definitely drug-related AE's were reported in 11
(48%) placebo/laronidase subjects, and in 10 (45%) laronidase/laronidase
subjects. Among these, infusion associated reactions (IAR's) occurred in
7 (30%) placebo/laronidase subjects and in 8 (36%) laronidase/laronidase
subjects. IAR's were defined as all drug-related AE's occurring on the
day of infusion, except for those identified by protocol required
assessments prior to the infusion.

The most frequently reported IAR in both treated groups was flushing (1
/ 23 placebo/laronidase subject and 3 / 22 laronidase/laronidase
subjects). The majority of these IAR's (flushing, rash) were reported as
mild. There were 3 / 23 placebo/laronidase subjects and 2 / 22
laronidase/laronidase subjects with IAR's that required medication with
antipyretics and / or antihistamines. None required drug infusion rate
decrease or interruption, or use of steroids.

Among other drug-related AE the most common (defined by the sponsor as 2
or more subjects) in the laronidase/laronidase group were arthropathy
(14 %) and flushing (14 %), and in the placebo/laronidase group were
arthralgia (9 %) and leg pain (9 %).

All AE's with incidence higher than 30 % in either treatment group
during the open label extension Study 006 were reported according to
WHO-ART terminology and identified by the Preferred Term. Headache was
the most commonly reported AE, with 57% and 45% incidence in the
placebo/laronidase and the laronidase/laronidase groups, respectively,
followed by rhinitis (43% and 41% in placebo/laronidase and
laronidase/laronidase groups, respectively). Coughing and pharyngitis
followed with approximately 30 % of subjects reporting these events,
with similar frequencies among the 2 treatment groups. Gastrointestinal
AE's were more prevalent in the placebo/laronidase group, with 16
subjects (70%) reporting events, contrasted with 10 (45%) reporting in
the laronidase/laronidase group. The specific events ≥ 30 % were nausea,
diarrhea and vomiting.

In comparing the incidence of the AE's with incidence ≥ 30% within each
treatment group between Studies 003 and 006, the 23 placebo-treated
subjects experienced a reduction in these AE's as they were treated with
laronidase during the 24 weeks of the open label study. The incidence of
these most frequent AE's in the laronidase group during the double blind
study remained the same during the open label study.

The protocol called for IgE and complement testing in subjects
experiencing moderate or severe IAR's. 3 subjects in the
placebo/laronidase group with moderate IAR's were not tested (protocol
deviation).

Data from AE's related to study drug occurring in non-infusion days was
inconclusive, as most AE's under specific preferred terms were observed
in single subjects. GI system symptoms were more common in the
placebo/laronidase subjects.

#### **[Deaths and SAE's]{.underline}**

There was one death on Study 006. Subject (30502) in the
placebo/laronidase group died at Week 16 of Study 006 of complications
from upper respiratory tract infection and bronchitis. This 7 year old
male had a history of central and obstructive sleep apnea. The
investigator suggested tracheostomy be considered, and was still under
consideration at the time of the event. Six days after infusion 16, the
subject was found dead in his bed at home. Autopsy findings revealed
marked chronic tracheo-bronchitis with possible acute exacerbation with
sepsis. This SAE is classified as unrelated to study drug.

The most notable SAE was:

Subject 60607 (placebo/laronidase) experienced a life-threatening
infusion reaction. This is a 15 year old male with history of severe
lung restriction, cardiac involvement and anxiety who reported nausea
and lightheadedness after the 11^th^ infusion of laronidase, resolving
spontaneously. At the 12^th^ infusion, the subject had respiratory
distress with hyperventilation and decreased oxygen saturation. The
investigator treated the subject for possible atelectasis and anxiety,
with improvement. This initial SAE was reported as remotely associated
with the study drug. From April 8, 2002 until October 16, 2002 the same
subject developed intermittent but progressively worse episodes of
urticarial rash and hypoxemia, despite higher doses of anti-histamines
and the use of intravenous corticosteroids. His April 2002 plasma
complement activation results and IgE were positive, but with a negative
skin testing with the enzyme.

On October 16, 2002 (extension week 62), three hours after starting the
infusion, the subject developed a rash with \"facial flushing\" and
hypoxemia necessitating biPAP and then oxygen. The infusion was
apparently stopped and Solu-Medrol administered. Soon thereafter,
intermittent apnea developed and the subjects was transported to an ER
where he was noted to be cyanotic with \"urticarial lesions extending
from the face to the groin area.\" The subject\'s airway could not be
maintained, attempts at oral intubation were unsuccessful and an
emergency cricothyroidomoty was performed. During this time, the subject
was bradycardic and epinephrine was administered. Following
tracheostomy, initial blood gases showed hypoventilation and hypoxemia.
The subject was transported to the ICU where he is reported to be
stabilizing. The neurological status is unknown to the sponsor. The
investigator reported the events as \"definitely related to study
medication.\"

Notably, during the open label extension, obstructive sleep apnea was
diagnosed and CPAP was prescribed but the subject was intolerant of it
and intermittent nocturnal oxygen was prescribed instead along with
periodic use of biPAP.

There were 7 other SAE that do not raise clear concerns regarding
drug-relatedness:

Subject 30101 (placebo/laronidase) had repair of a recurrent umbilical
hernia, where initial occurrence and repair were several years prior to
entry into this study.

Subject 30309 (placebo/laronidase) is a 17 year old male status post
heart transplantation where chronic rejection was detected through a
heart biopsy, and treated with revised immunosuppressive regimen.

Subject 50807 (placebo/laronidase) is a 14 year old female who
experienced a chocking episode due to food obstruction of larynx, which
resolved with prompt treatment.

Subject 30608 (laronidase/laronidase) is a 7 year old female who was
hospitalized for otitis media during the baseline period of Study 003,
underwent a tympanoplasty after week 7 on Study 006.

Study 30806 (laronidase/laronidase) is a 44 year old male with a SAE
described in Study 003. In summary, patient had complications of aortic
valvuloplasty, including cardiac arrest and sepsis, but made full
recovery during Study 003. He was hospitalized due to worsening of
palpitations after week 21 into the Open Label Extension study. No
abnormalities were uncovered despite extensive assessments and the
subject was discharged without specific treatment. This SAE is unrelated
to study drug.

There were also two subjects with one day hopitalizations for placement
of vascular access devices.

#### **[Clinical Laboratory Evaluations]{.underline}**

No clinically relevant changes were observed for any mean serum
chemistry values over the 24 weeks of Study 006.

From the hematologic parameters, platelet counts showed a trend to
increase with laronidase treatment. This had been suggested by Study 003
experience as well (Table 35).

Table 35. Mean ± SD changes in platelet counts from baseline into Study
003 to week 24 of Study 006.

  ------------------- --------------------------- ------- ------------------------ -------
  **Timepoint**       **Laronidase/laronidase**   **n**   **Placebo/laronidase**   **n**

  **Baseline**        218 ± 52                    22      236 ± 66                 21

  **Entry**           253 ± 72                    22      212 ± 47                 21

  **Week 24**         284 ± 83                    22      271 ± 44                 21
  ------------------- --------------------------- ------- ------------------------ -------

*Reviewer comment: These changes occurred within the normal range of
platelet counts. However, there is a suggestion that laronidase
treatment resulted in the increments in platelets. The
placebo/laronidase group had a decrease in platelet counts during Study
003, but upon treatment with laronidase had a mean increase of 58.7 X
10^3^/µL. The laronidase/laronidase group had shown an increase in
platelet count during study 003 and this was further slightly increased
during study 006. A possible interpretation of these data is that
decreases in spleen size (such as those observed during the Phase 1
study) would cause a parallel reduction in platelet removal and
destruction. This hypothesis is physiologically plausible, but unproven,
particularly given the lack of spleen volume changes in both Studies 003
and 006.*

No clinically relevant changes were observed for any mean parameters
assessed by urinalysis over the 24 weeks of Study 006.

#### **[Vital signs and physical findings]{.underline}**

No clinically relevant changes were observed for vital signs and
physical examination findings over the 24 weeks of Study 006.

#### **[ECG and Echocardiogram findings]{.underline}**

Two subjects in the placebo/laronidase group had echocardiographic
changes summarized in this review under tertiary endpoints.

#### **[Other findings]{.underline}**

Forty of the 45 subjects participating in the Open label Extension Study
006 had developed IgG antibodies confirmed by RIP. Nearly all (21 / 23)
placebo/laronidase subjects seroconverted during study 006. Twenty of
the 22 laronidase-treated subjects were IgG (+) at study 006 entry. One
laronidase-treated subject developed IgG antibodies during the Open
label extension. Two laronidase / laronidase subjects became IgG
negative after a relatively long period of IgG seropositivity, during
study 006. By week 24, 19 laronidase/laronidase treated subjects were
IgG (+). No correlation between AE's or IAR's could be established with
the IgG antibody status, given the few numbers of IgG (-) subjects in
both treatment groups.

###### Study 006 Summary {#study-006-summary .Style2}

Study 006 was conducted as an uncontrolled open label extension trial of
laronidase in the 45 subjects that participated in the double blind
randomized, placebo-controlled Study 003. The 22 subjects assigned to
laronidase and the 23 subjects assigned to placebo weekly intravenous
infusions during Study 003 all received the same weekly dose of
laronidase (100 U / kg) for a period of 24 weeks, with data included in
this BLA submission. This study remains ongoing, with longer term safety
data still being collected.

The % FVC showed no changes for both the laronidase/laronidase group and
the placebo/laronidase group. This observation is unsupportive of the
apparent small but statistically significant improvement in % FVC seen
in the laronidase-treated group during Study 003.

The 6MWD test, showed some marginal increments (approximately 20 meters)
in the distance walked in 6 minutes, with a similar magnitude for both
treatment groups (laronidase/laronidase and placebo/laronidase).

The trend seen during Study 003 of more marked increments in these
endpoints in the young, female subset with less severe disease at
baseline is not reproduced here. Data from secondary and tertiary
endpoints was equally inconclusive and unsupportive, with the exception
of the reduction noted in urinary GAG concentrations and in the liver
volume.

No conclusions regarding efficacy may be drawn from these data.

Safety events were notable for the life-threatening infusion reaction
experienced in one subject in the placebo/laronidase group.

Antibody formation was again seen to occur in nearly all subjects, by
both the less specific ELISA and the non-quantitative but more specific
RIP assay.

[]{#__RefHeading___Toc27725250 .anchor}Summary of Efficacy

MPS I is a complex disorder characterized by progressive accumulation of
glycosaminoglycans in multiple tissues and organs, at different rates
for different individuals. There are multiple clinical aspects of the
disease warranting evaluation and for which efficacious treatment would
be worthwhile. Based on in vitro binding studies in human MPS I
fibroblasts and pre-clinical experience with appropriate canine and
feline models of MPS I, a dose of 100 U / kg of laronidase to be given
intravenously on a weekly basis was selected for all the clinical
development of this product.

An open label, uncontrolled Phase 1 trial of laronidase was conducted in
a group of 10 subjects with MPS I, 8 of whom had the Hurler- Scheie form
(intermediate severity and progression to death). In this group of
subjects, laronidase treatment reduced liver and spleen volumes and
significantly reduced urinary GAG's in a matter of a few weeks. The
study-observed changes in other endpoints of clinical importance to
patients with MPS I were variable and of uncertain clinical
significance. Specifically, assessments related to cardiac function,
muscle-skeletal, airway and central nervous system function suggested an
overall favorable trend. However, these data obtained from an open label
uncontrolled study cannot provide strong support for laronidase efficacy
in MPS I.

The main support for a Biomarin claim of efficacy comes from a single
randomized, placebo-controlled, multicenter trial of laronidase at 100 U
/ kg weekly vs. placebo in a group of 45 subjects with MPS I for 26
weeks. The two primary endpoints selected were the difference in percent
of predicted FVC (% FVC) as change from baseline to week 26 and the
difference in the 6 minute walk distance (6MWD) as change from baseline
to week 26. In order to explore the effect of laronidase in other
important clinical areas affected in MPS I secondary and tertiary
endpoints were chosen. Parameters assessing sleep apnea, joint range of
motion, liver volume, pain scores, heart function, degree of disability
and urinary GAG's were assessed and the data analyzed to provide
additional support for the effect in the primary endpoints. Similar to
the distribution of subjects in the Phase 1, most were patients with
classified as the Hurler-Scheie syndrome.

Twenty two subjects were randomized to laronidase and 23 subjects to
placebo. The 2 groups complied with study agent administration and study
visits. After 26 weeks the laronidase group had a 5.3 % increase from
baseline in the % FVC, whereas the placebo group had a 0.6 % decrease in
% FVC, with the % FVC calculated on the basis of the baseline height of
the subjects. The difference was statistically significant, but was only
marginally meaningful.

In the 6 MWD, the laronidase group walked a mean 19.7 meters more at
week 26 than at baseline, whereas the placebo group walked a mean of
18.4 meters less than at baseline. The difference between groups did not
reach statistical significance. Subset analysis in both co-primary
endpoints revealed a more favorable trend in female subjects, younger
subjects, and those with less severe disease. However a firm conclusion
regarding the effect of these factors cannot be drawn from the limited
data obtained in this trial.

No general conclusions supportive of efficacy can be drawn from results
on the secondary or tertiary endpoints. The data support an active
effect to produce reductions in liver volume and urinary GAG's, as seen
in the Phase 1 study.

The Phase 3 trial was followed by an Open Label Extension study 006. All
45 subjects that took part in the Phase 3 trial are currently receiving
the same laronidase dose used for the laronidase group in the controlled
trial, and the study is currently ongoing. Data from the first 24 weeks
was collected, analyzed and submitted with this submission. By week 24
of the Open Label Extension study, the mean % FVC has not changed for
the 22 subjects continuing on the same laronidase treatment or for the
23 subjects who were switched to laronidase. These data cannot be
explained on the basis of individual variations or "seasonal" changes.

In the 6 MWD, the 22 subjects originally assigned to laronidase
treatment were able to walk an additional mean of 23.2 meters at week 24
of the extension study, and the placebo/laronidase group was able to
walk a mean of 23.8 meters further at week 24. Again, no conclusion can
be drawn from these uncontrolled and unblinded data with a small
clinical effect.

Secondary and tertiary clinical endpoints were again unsupportive of any
conclusion regarding efficacy. Liver volume was reduced by a mean of
12.6 % and urinary GAG levels by a mean of 69 % in the
placebo/laronidase subjects.

Antibodies against laronidase formed in most subjects, and no conclusion
regarding the impact of these antibodies on efficacy can be formed.

[]{#__RefHeading___Toc27725251 .anchor}Summary of Safety

Any safety analysis of a product studied in MPS I must be performed in
light of the background of significant morbidity that is associated with
the enzyme deficiency. Almost all subjects that participated in the
Phase 1 or the Phase 3 studies had experienced at least one adverse
event (AE). The safety database is 59 subjects exposed to laronidase for
variable periods of time, with a minimum of 24 weeks for the placebo
subjects switched to laronidase in the Open Label Extension to more than
3 years for the subjects that are still being treated with laronidase
infusions under the Phase 1 protocol.

The safety of laronidase treatment can be best assessed by looking at
the study 003 controlled data. In that study the overall rate of AE's
was very similar between the 2 treatment groups. Infusion associated
reactions (mostly flushing and rash) were equally similar in the 2
groups, despite the fact that almost all laronidase-treated subjects
developed antibodies against the enzyme. Anti-laronidase antibodies did
not generally appear to be associated with specific adverse events. Two
notable exceptions to the lack of correlation are subject 008 that
participated in the Phase 1 study and subject 60607 in the Phase 3
study. The former died from a possible viral illness that led to
respiratory distress and respiratory arrest. In that subject
anti-laronidase IgG antibody titers were high, and there was evidence of
immune complex deposition in glomerular capillaries without any
histopathological changes. A link between this finding and the worsening
of the subject's severe pulmonary involvement cannot be ruled out. The
latter subject (60067) developed progressively worse episodes of
hypoxemia and rash a few weeks after being switched from placebo to
laronidase treatment during the Open Label Extension study. These events
occurred in the face of positive anti-laronidase IgE levels and plasma
complement activation, and 5 months after the initiation of laronidase
culminated with an anaphylactic reaction necessitating an emergency
cricothyroidomoty. This particular subject also had a response lower
than the group mean in both primary endpoints, as well as 9 % reduction
in liver volume and an 11 % reduction in urinary GAG. The event also
raises for consideration the value of developing a reproducible and
reliable anti-laronidase IgE test to be used in conjunction with
laronidase treatment.

Another death in the Phase 1 study and a death occurring in the Open
Label Extension are regarded as unrelated to laronidase treatment.
Subject 002 died as a result of spinal cord injury after spinal fusion
surgery after more than 2 years in the study. Subject 30502 in the
placebo/laronidase group died at Week 16 of Study 006 of complications
from upper respiratory tract infection, bronchitis and sepsis. All other
SAE's reported were related to the morbidity of MPS I and not to
laronidase treatment.

[]{#__RefHeading___Toc27725252 .anchor}Conclusions and Recommendations

The studies presented in the submission provide a suggestion of efficacy
of laronidase in the treatment of patients with MPS I. However these
data are limited in both statistical strength and in clinical
significance. The weight of this conclusion derives from the Phase 3
double blind study 003, which shows a statistically, but not clinically,
significant change in % FVC in the laronidase group as compared to
placebo control. The other co-primary endpoint, the 6 minute walk test
did not reach statistical significance for a treatment-associated
difference.

Exploratory analyses of the data suggest that the benefit of the
treatment, if any, may not be homogeneous across the MPS I subjects. A
subset of females and/or younger subjects and/or those with less severe
disease may be more prone to benefit. However in addition to being
post-hoc exploratory analyses, there are few subjects in these studies,
and these factors cannot be readily isolated for examination.
Consequently, firm conclusions regarding subsets more or less
appropriate for treatment with this dose and regimen may be infeasible.

Two markers of in vivo enzyme activity were associated with significant
reductions during the 26 weeks of Study 003: liver size reductions and
urinary GAG concentration. The response of these markers to laronidase
has been consistently shown also in the pre-clinical experiments and in
the Phase 1 clinical trial, as well as in the placebo-treated subjects
switched to laronidase treatment during the Open label Extension.
However, these markers cannot be viewed as surrogates for improving
clinical endpoints that contribute to the morbidity and untimely
mortality of MPS I.

Possible reasons for non-robust indications of clinical benefit (besides
the possibility that the treatment is ineffective) may include
inadequate knowledge regarding dose-regimen-response so that an optimal
dose and regimen was not evaluated in these studies, insufficient
duration of the controlled study to permit robust demonstration of
efficacy, and possibly selection of a patient population less
susceptible to benefits on the parameters examined than a different
portion of the disease patient population.

[]{#__RefHeading___Toc27725253 .anchor}Appendix A: Tertiary Endpoints of
Study ALID-003

**Total Respiratory Events Index of the Sleep Study**

The total respiratory event index is calculated from data generated in
the baseline and week 26 sleep studies, as follows: number of apneas +
number of hypopneas + respiratory effort-related arousals / hours of
sleep. Mean changes from baseline to week 26 were compared in the
treatment groups by ANOVA. Biomarin also assessed the total amount of
sleep time spent with oxygen saturation below 90 % and below 80 % during
the sleep studies. This index of hypoxemia was only descriptively
summarized in the 2 treatment groups, and was not subject to hypothesis
testing.

The laronidase-treated group showed a mean reduction of 3.1 events /
hour, whereas the placebo-treated group had an increase of 0.3 events /
hour at week 26. The difference from placebo did not reach statistical
significance (p=0.118). These results were consistent across study
centers. No clinical significance can be attributed to these data.

**Pain Scales from the CHAQ / HAQ**

The range of the pain scale is 0 to 3 with lower scores indicating less
pain. The endpoint for the statistical comparison using ANOVA was the
mean change in pain scores from baseline to week 26 between the
treatment groups. The mean (± SD) baseline scores for the
placebo-treated and laronidase-treated subjects were low and similar, at
1.0 (± 0.6) and 1.1 (± 0.89), respectively. Changes at week 26 for both
groups were small, with scores of 0.8 ± 0.79 for placebo and 0.7 ± 0.87,
and the difference in the adjusted mean changes from placebo was not
statistically significant, using ANOVA (p=0.51).

**Joint Range of Motion (ROM) Variables**

Table 36 shows mean changes in joint ROM (angles) from baseline to week
26.

  -------------------- -------------- ---------------- -------------- ---------
  **Joint**                           **Laronidase**   **Placebo**    **p
                                                                      value**

  **R Shoulder         **Baseline**   22.9 ± 13.3      28.9 ± 14.1    
  extension**                                                         

                       **Week 26**    27.7 ± 10.7      27.0 ± 8.6     

                       **Change**     5.1              \- 1.9         0.05

  **L Shoulder         **Baseline**   25.6 ± 10.6      28.0 ± 12.2    
  extension**                                                         

                       **Week 26**    27.7 ± 9.6       27.1 ± 6.9     

                       **Change**     2.3              \- 0.8         0.46

  **R Knee extension** **Baseline**   \- 12.1 ± 13.4   \- 14.3 ± 16.3 

                       **Week 26**    \- 9.0 ± 11.5    \- 15.6 ± 16.7 

                       **Change**     \- 1.9           \- 1.3         0.88

  **L Knee extension** **Baseline**   \- 12.3 ± 13.8   \- 15.4 ± 17.1 

                       **Week 26**    \- 9.6 ± 11.9    \- 14.9 ± 16.6 

                       **Change**     \- 4.0           0.5            0.48

  **R knee flexion**   **Baseline**   106.7 ± 19.9     114.4 ± 11.3   

                       **Week 26**    115.1 ± 18.0     118.6 ± 12.3   

                       **Change**     8.0              4.2            0.40

  **L knee flexion**   **Baseline**   107.4 ± 20.3     117.0 ± 11.4   

                       **Week 26**    116.6 ± 17.0     118.5 ± 15.7   

                       **Change**     8.9              1.5            0.09
  -------------------- -------------- ---------------- -------------- ---------

Higher values (in angles of flexion or extension) reflect less severe
disease. For knee extension, the measures represent degrees of
hyperflexion, and a more negative value reflects more severe disease. In
the laronidase-treated subjects, modest improvements were observed after
26 weeks of study in the range of motion of all 6 joints. These
differences were slightly more pronounced in the comparisons among the
more severely affected subjects (below the median aggregate value for
each joint assessed). The findings were consistent across clinical
sites, except for worsening of bilateral knee extension and flexion in
the laronidase-treated subjects in the United Kingdom.

*Reviewer comment: Biomarin did not present the range of motion for the
joints studied in the subset of less affected individuals, so an
impression on the absolute level of impairment at baseline cannot be
formed. A conclusion on the clinical significance of the changes shown
cannot be drawn. Furthermore, the high degree of multiplicity of tests
on this tertiary endpoint impairs the ability to form and definitive
conclusions.*

**Global Components of the Child Health Questionnaire (parent /
caregiver and child subject components) or from the Short-Form 36
(SF-36)**

There were multiple analyses performed on components of these tools.
Most did not show statistically significant differences between groups.
These analyses provide no support for efficacy of laronidase.

**Height in pre-pubertal subjects**

Only pre-pubertal subjects who had not reached Tanner Stage 2 by the end
of week 26 were included in the analysis (7 subjects in each treatment
group). Based on mean changes over the 26 week study period, the 7
laronidase-treated subjects grew 4.7 cm compared to 2.7 cm for the
placebo-treated subset. The normal pre-pubertal height increase is
approximately 5 cm per year. Many subjects had joint contractures at
baseline, particularly at the knee. During the course of the study a
slightly favorable trend in improved ROM of the knee in the
laronidase-treated group was observed. The consequent release of these
contractures may have accounted for some of the gains in height, more so
in the laronidase group than in the placebo group. Therefore these data
may not reflect linear growth, and no conclusions can be formed.

There were even fewer subjects with more than one historical standing
height to be able to calculate pre-study slope values of growth
velocity; therefore a clinically meaningful comparison of growth
velocity was not possible between the treatment groups.

**Shifts in Ophthalmology Measures, Visual Acuity and Tonometry**

No conclusive data is derived from these assessments in the 2 treatment
groups.

**Cardiac Function based on EKG and echocardiography**

Using standard EKG tracings, no clinically relevant changes in any
parameters (heart rate, intervals, sinus rhythm, left or right
ventricular hypertrophy, evidence of prior MI, non-specific ST wave
abnormalities) were present in either treatment group.

No clinically relevant changes were seen in any of the echocardiographic
parameters in either treatment group. Hypothesis testing failed to
reveal any statistically significant changes in these parameters.

**Investigator Global Assessment**

This assessment is the investigator's global perception at week 26 as
compared to baseline for each subject. Six of 22 laronidase subjects
were considered as having marked or moderate improvement, whereas 2 of
23 placebo-treated subjects were considered by the investigators to have
had the same improvement magnitude. 19 / 22 placebo-treated subjects and
13 / 22 laronidase-treated subjects were considered to have mild
improvement or no change at week 26. Only one subject was designated as
having marked worsening, laronidase-treated subject 30806, who had
complications following heart valve surgery unrelated to the treatment
group allocation. No benefits were apparent from these data.

**Forced Expiratory Volume (FEV), Total Lung Capacity (TLC), and
Diffusing Capacity (D~L~)**

Baseline values for the 3 parameters were similar. Changes from baseline
to week 26 were small and similar for both treatment groups.

**Resource Utilization**

Data on this endpoint was not included in the study report. The sponsor
states: "Analyses of these data will be documented in a separate
report."

**Heart Rate, Respiratory Rate and Oxygen Saturation**

Heart and respiratory rates, as well as O~2~ saturation were determined
before, immediately after and 2 minutes after the 6 minute walk distance
test. No statistically or clinically meaningful differences were
presented in these measurements between the treatment groups at baseline
or at any of the timepoints for assessment, including week 26.

**Composite endpoint**

Biomarin created a post-hoc composite endpoint for a post-hoc
exploratory analysis. The composite endpoint is based on changes in %
FVC, 6MWD, AHI, shoulder flexion and liver volume. A responder to this
composite endpoint is a subject who shows net improvements across the 5
domains. Using these exploratory criteria, 77 % of laronidase-treated
subjects were responders and 17 % of placebo-treated subjects were
responders. Even when the domain of hepatomegaly (which is not
interpretable in terms of clinical meaningfulness) is removed from the
composition of the endpoint the resulting analysis still shows 13 of 22
laronidase-treated subjects as responders, and 5 / 23 placebo-treated
subjects as responders.

*Reviewer comment: This post hoc analysis has several flaws that
undermine a suggestion of clinical significance for the laronidase based
on the data analyzed. It is an analysis conducted only after the data
was unblinded. Bias in selection of which endpoints are included cannot
be ruled out. The nature of the composite may also make it difficult to
interpret, combining potentially clinically meaningful evaluations with
one that is not readily interpretable. By categorizing each domain into
improved and not improved, it also implies that any degree of
improvement in a specific domain is clinically significant (to be
consider it a response), which is unsubstantiated.*

*Other composites of similar or other endpoints can also be formulated,
and the multiplicity problem will confound drawing any conclusions based
on such analyses.*

[]{#__RefHeading___Toc27725254 .anchor}Appendix B: Tertiary Endpoints of
Study ALID-006

#### **[Total respiratory event index and total sleep time with hypoxemia]{.underline}**

The placebo/laronidase group had a small improvement in this index (16.6
± 14.0 at study 006 entry to 13.0 ± 7.8 at week 24) compared with the
laronidase/laronidase group, with a small degree of worsening during
Study 006 (from 19.7 ± 16.8 at study entry to 21.9 ± 21.4 at week 24).
No significant changes were also noted for either treatment group for
the time spent with oxygen saturation below 90 % during sleep.

#### **[Pain scale]{.underline}**

The pain scale component of the CHAQ / HAQ reflects partially the
functional status of the subjects, with a lower score indicating less
pain. The scale range is 0 to 3. The mean change from entry to week 24
for the placebo/laronidase group was -- 0.3 and the mean change for the
laronidase/laronidase group during the same period was 0.1. Over the
course of the 50 weeks of Study 003 and 006 combined small improvement
in the degree of pain was noted for both groups.

*Reviewer's comments: Assessment of pain in a scale, even with
appropriate methodology, validated scales and measures to prevent bias,
is difficult to accomplish without taking into account the concomitant
use of drugs or physical measures to relieve pain. In addition, the pain
here relates to a variety of causes, ranging from arthritic pains to
headaches related to sinusitis or increased intra-cranial pressure. In
this context, evaluation of changes in perception of pain of a
multifactorial nature is difficult.*

#### **[Joint Range of Motion]{.underline}**

For shoulder extension and for knee flexion higher values of ROM reflect
less severe disease. For knee extension, more negative values reflect
more severe disease. Table 37 shows only modest improvements or no
change for the joint range of motion in the 3 joint groups assessed for
both treatment groups.

Table 37. Mean ± SD during Studies 003 and 006 for Joint ROM for the 2
treatment groups

  ------------- ---------- --------------------------- ------- ------------------------ -------
  **Joint**                **Laronidase/laronidase**   **n**   **Placebo/laronidase**   **n**

  **R Shoulder  Baseline   22.9 ± 13.3                 18      28.9 ± 14.1              23
  extension**                                                                           

                Entry      27.7 ± 10.7                 20      27.0 ± 8.6               23

                Week 24    29.8 ± 14.0                 20      32.2 ± 11.2              23

  **L Shoulder  Baseline   25.6 ± 10.6                 18      28.0 ± 12.2              23
  extension**                                                                           

                Entry      27.7 ± 9.6                  20      27.1 ± 6.9               23

                Week 24    29.4 ± 13.1                 20      30.3 ± 11.9              23

  **R Knee      Baseline   \- 12.1 ± 13.4              19      \- 14.3 ± 16.3           23
  extension**                                                                           

                Entry      \- 9.0 ± 11.5               22      \- 15.6 ± 16.7           23

                Week 24    \- 6.2 ± 9.8                22      \- 12.4 ± 16.3           23

  **L Knee      Baseline   \- 12.3 ± 13.8              19      \- 15.3 ± 17.1           23
  extension**                                                                           

                Entry      \- 9.5 ± 11.9               22      \- 14.9 ± 16.6           23

                Week 24    \- 6.3 ± 12.1               22      -12.6 ± 15.4             23

  **R knee      Baseline   106.7 ± 19.9                20      114.4 ± 11.3             23
  flexion**                                                                             

                Entry      115.1 ± 18.0                22      118.6 ± 12.3             23

                Week 24    116.1 ± 17.1                22      118.3 ± 15.1             23

  **L knee      Baseline   107.4 ± 20.3                20      117.0 ± 11.4             23
  flexion**                                                                             

                Entry      116.6 ± 17.0                22      118.5 ± 15.7             23

                Week 24    117.7 ± 16.6                22      119.9 ± 15.6             23
  ------------- ---------- --------------------------- ------- ------------------------ -------

#### **[Global Components of CHQ or SF-36]{.underline}**

The CHQ was used to assess global components for each subject. A parent
or caregiver completed one section of the questionnaire (CHQ-PF50), and
the child completed another part (CHQ-CF-87). Higher scores reflect
better responses. In addition, parents evaluated their own QoL by using
SF-36. In the latter instrument, higher scores also reflect better
responses. No conclusion can be drawn from the data and there were no
differences between the 2 treatment groups.

#### **[Growth Velocity]{.underline}**

Changes in height were assessed in pre-pubertal children through Studies
003 and 006. Subjects who have not reached Tanner Stage 2 by Week 24 of
the open label study were included. Normal pre-pubertal height increase
is approximately 5 cm per year. As mentioned in the report for Study
003, too few pre-pubertal subjects had more than one historical standing
height for calculation of pre-study growth slope values. After
completion of Study 003, some of the pre-pubertal subjects entered
puberty during the 24 weeks of the open label extension. Some of the
growth in height can also be attributed to release of joint
contractures, particularly in the knees, rather than a true effect on
linear growth.

[Laronidase/laronidase group]{.underline}: Seven subjects randomized to
laronidase during Study 003 had a mean growth of 4.7 cm. Two of these
subjects entered puberty during Study 006. The remainder 5 pre-pubertal
children had grown a mean of 4.6 cm from baseline in Study 003 to week
24 of Study 006. The mean growth from entry into Study 006 until Week 24
for these 5 children was 0.4 cm.

[Placebo/laronidase group]{.underline}: Seven subjects randomized to
placebo during Study 003 had a mean growth of 2.7 cm. Three of these
subjects entered puberty during Study 006. The remainder 4 pre-pubertal
children had grown a mean of 4.9 cm from baseline in Study 003 to week
24 of Study 006. The mean growth from entry into Study 006 until week 24
for these 4 children was 1.7 cm.

#### **[Visual acuity, ophthalmologic and slit lamp exam, tonometry, fundoscopy]{.underline}**

[Fundoscopic examination]{.underline}: From the subjects that had
baseline and/or study 006 entry abnormal fundoscopic findings, the
proportion of shifts to a normal fundoscopy were identical in the 2
treatment groups: 1 left eye and 1 right eye shifted from abnormal to
normal in each of the treatment groups.

[Slit lamp measurements]{.underline}: No shifts were observed from
abnormal to normal during study 006 in either treatment group. In each
group, 1 subject (one eye) shifted from normal to abnormal slit lamp
findings.

[Visual acuity]{.underline}: No conclusion on the laronidase effect can
be formed from the visual acuity data assessed with the Snellen chart.

[Tonometry]{.underline}: Most subjects in both treatment groups had
normal eye pressures at Study 003 baseline and at Study 006 entry.
Shifts from abnormal to normal or vice versa were too few and no
conclusive effect of treatment can be assessed from the data.

#### **[Cardiac Function]{.underline}**

No clinically significant changes were observed in the
electrocardiographic tracings in subjects of both treatment groups
during the 24 weeks of Study 006.

There were only 2 clinically significant echocardiographic changes
during Study 006: one subject in the placebo/laronidase group had mild
pericardial thickening at week 24 which was not present at study entry,
and one subject on the laronidase/laronidase group had moderately
enlarged left atrium, a finding also not present at study entry.

#### **[Forced expiratory volume in one second]{.underline}**

No mean changes were seen in either treatment group in the FEV1 from
baseline to study 006 entry or from study entry to week 24.

#### **[Total Lung Capacity]{.underline}**

No mean changes were seen in either treatment group in the TLC from
baseline to study 006 entry or from study entry to week 24.

#### **[Diffusing Capacity]{.underline}**

No mean changes of clinical significance were seen in either treatment
group in the diffusing capacity from baseline to study 006 entry or from
study entry to week 24.

#### **[Heart rate, respiratory rate and O2 saturation]{.underline}**

No mean changes of clinical significance were seen in either treatment
group in the heart rate, respiratory rate or in O~2~ saturation from
baseline to study 006 entry or from study entry to week 24.