Enzyme replacement therapy for mucopolysaccharidosis VI: Growth and pubertal development in patients treated with recombinant human N-acetylgalactosamine 4-sulfatase.

BACKGROUND AND METHODS: Growth failure is characteristic of untreated mucopolysaccharidosis type VI (MPS VI: Maroteaux-Lamy syndrome). Growth was studied in fifty-six MPS VI patients (5 to 29 years old) prior to and for up to 240 weeks of weekly infusions of recombinant human arylsulfatase B (rhASB) at 1 mg/kg during Phase 1/2, Phase 2, Phase 3 or Phase 3 Extension clinical trials. Height, weight, and Tanner stage data were collected. Pooled data were analyzed to determine mean height increase by treatment week, growth impacts of pubertal status, baseline urinary GAG, and age at treatment initiation. Growth rate for approximately 2 years prior to and following treatment initiation was analyzed using longitudinal modeling. RESULTS: Mean height increased by 2.9 cm after 48 weeks and 4.3 cm after 96 weeks on enzyme replacement therapy (ERT). Growth on ERT was not correlated with baseline urinary GAG. Patients under 16 years of age showed greatest increases in height on treatment. Model results based on pooled data showed significant improvement in growth rate during 96 weeks of ERT when compared to the equivalent pretreatment time period. Delayed pubertal onset or progression was noted in 10 patients entering the clinical trials; all of whom showed progression of at least one Tanner stage during 2 years on ERT, and 6 of whom (60%) completed puberty. CONCLUSION: Analysis of mean height by treatment week and longitudinal modeling demonstrate significant increase in height and growth rate in MPS VI patients receiving long-term ERT. This impact was greatest in patients aged below 16 years. Height increase may result from bone growth and/or reduction in joint contractures. Bone growth and resolution of delayed puberty may be related to improvements in general health, bone cell health, nutrition, endocrine gland function and reduced inflammation.

Enzyme replacement therapy for mucopolysaccharidosis VI: evaluation of long-term pulmonary function in patients treated with recombinant human N-acetylgalactosamine 4-sulfatase.

Pulmonary function is impaired in untreated mucopolysaccharidosis type VI (MPS VI). Pulmonary function was studied in patients during long-term enzyme replacement therapy (ERT) with recombinant human arylsulfatase B (rhASB; rhN-acetylgalactosamine 4-sulfatase). Pulmonary function tests prior to and for up to 240 weeks of weekly infusions of rhASB at 1 mg/kg were completed in 56 patients during Phase 1/2, Phase 2, Phase 3 and Phase 3 Extension trials of rhASB and the Survey Study. Forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1) and, in a subset of patients, maximum voluntary ventilation (MVV), were analyzed as absolute volume in liters. FEV1 and FVC showed little change from baseline during the first 24 weeks of ERT, but after 96 weeks, these parameters increased over baseline by 11% and 17%, respectively. This positive trend compared with baseline continued beyond 96 weeks of treatment. Improvements from baseline in pulmonary function occurred along with gains in height in the younger group (5.5% change) and in the older patient group (2.4% change) at 96 weeks. Changes in MVV occurred earlier within 24 weeks of treatment to approximately 15% over baseline. Model results based on data from all trials showed significant improvements in the rate of change in pulmonary function during 96 weeks on ERT, whereas little or no improvement was observed for the same time period prior to ERT. Thus, analysis of mean percent change data and longitudinal modeling both indicate that long-term ERT resulted in improvement in pulmonary function in MPS VI patients.

Long-term follow-up of endurance and safety outcomes during enzyme replacement therapy for mucopolysaccharidosis VI: Final results of three clinical studies of recombinant human N-acetylgalactosamine 4-sulfatase.

UNLABELLED: The objective of this study was to evaluate the long-term clinical benefits and safety of recombinant human arylsulfatase B (rhASB) treatment of mucopolysaccharidosis type VI (MPS VI: Maroteaux-Lamy syndrome), a lysosomal storage disease. Fifty-six patients derived from 3 clinical studies were followed in open-label extension studies for a total period of 97-260 Weeks. All patients received weekly infusions of rhASB at 1 mg/kg. Efficacy was evaluated by (1) distance walked in a 12-minute walk test (12MWT) or 6-minute walk test (6MWT), (2) stairs climbed in the 3-minute stair climb (3MSC), and (3) reduction in urinary glycosaminoglycans (GAG). Safety was evaluated by compliance, adverse event (AE) reporting and adherence to treatment. RESULTS: A significant reduction in urinary GAG (71-79%) was sustained. For the 12MWT, subjects in Phase 2 showed improvement of 255+/-191 m (mean+/-SD) at Week 144; those in Phase 3 Extension demonstrated improvement from study baseline of 183+/-26 m (mean+/- SE) in the rhASB/rhASB group at Week 96 and from treatment baseline (Week 24) of 117+/-25 m in the placebo/rhASB group. The Phase 1/2 6MWT and the 3MSC from Phase 2 and 3 also showed sustained improvements through the final study measurements. Compliance was 98% overall. Only 560 of 4121 reported AEs (14%) were related to treatment with only 10 of 560 (2%) described as severe. CONCLUSION: rhASB treatment up to 5 years results in sustained improvements in endurance and has an acceptable safety profile.

Mutational analysis of 105 mucopolysaccharidosis type VI patients.

Mucopolysaccharidosis type VI (MPS VI; Maroteaux-Lamy syndrome) is a lysosomal storage disorder caused by mutations in the N-acetylgalactosamine-4-sulfatase (arylsulfatase B, ARSB) gene. ARSB is a lysosomal enzyme involved in the degradation of the glycosaminoglycans (GAG) dermatan and chondroitin sulfate. ARSB mutations reduce enzyme function and GAG degradation, causing lysosomal storage and urinary excretion of these partially degraded substrates. Disease onset and rate of progression is variable, producing a spectrum of clinical presentation. In this study, 105 MPS VI patients-representing about 10% of the world MPS VI population-were studied for molecular genetic and biochemical parameters. Direct sequencing of patient genomic DNA was used to identify ARSB mutations. In total, 83 different disease-causing mutations were found, 62 of which were previously unknown. The novel sequence changes included: 38 missense mutations, five nonsense mutations, 11 deletions, one insertion, seven splice-site mutations, and four polymorphisms. ARSB mutant protein and residual activity were determined on fibroblast extracts for each patient. The identification of many novel mutations unique to individuals/their families highlighted the genetic heterogeneity of the disorder and provided an appropriate cohort to study the MPS VI phenotypic spectrum. This mutation analysis has identified a clear correlation between genotype and urinary GAG that can be used to predict clinical outcome.

A follow-up study of MPS I patients treated with laronidase enzyme replacement therapy for 6 years.

Recombinant human alpha-L-iduronidase (Aldurazyme, laronidase) was approved as an enzyme replacement therapy for patients with the lysosomal storage disorder, mucopolysaccharidosis I (MPS I). In order to assess the long-term safety and efficacy of laronidase therapy, 5 of 10 patients in the original laronidase Phase 1/2 clinical trial were re-evaluated after 6 years of treatment. Lysosomal storage was further improved at 6 years (urinary glycosaminoglycans (GAG) excretion decreased 76%; mean liver size at 1.84% of body weight). Shoulder maximum range of motion was maintained or further increased and reached a mean 33.2 (R) and 25.0 (L) degrees gained in flexion and 34.0 (R) and 27.3 (L) degrees gained in extension. Sleep apnea was decreased in four of five patients and the airway size index improved. Cardiac disease evaluations showed no progression to heart failure or cor pulmonale but pre-existing significant valve disease did progress in some patients. Substantial growth was observed for the pre-pubertal patients, with a gain of 33 cm (27%) in height and a gain of 31 kg in weight (105%). In general, the evaluated patients reported an improved ability to perform normal activities of daily living. Overall these data represent the first evidence that laronidase can stabilize or reverse many aspects of MPS I disease during long-term therapy and that early treatment prior to the development of substantial cardiac and skeletal disease may lead to better outcomes.

Enzyme replacement therapy for mucopolysaccharidosis VI: a phase 3, randomized, double-blind, placebo-controlled, multinational study of recombinant human N-acetylgalactosamine 4-sulfatase (recombinant human arylsulfatase B or rhASB) and follow-on, open-label extension study.

OBJECTIVE: The objective of this Phase 3 study was to confirm the efficacy and safety of recombinant human arylsulfatase B (rhASB) treatment of mucopolysaccharidosis type VI (MPS VI; Maroteaux-Lamy syndrome), a rare, fatal lysosomal storage disease with no effective treatment. STUDY DESIGN: Thirty-nine patients with MPS VI were evaluated in a randomized, double-blind, placebo-controlled, multicenter, multinational study for 24 weeks. The primary efficacy variable was the distance walked in a 12-minute walk test (12MWT), whereas the secondary efficacy variables were the number of stairs climbed in a 3-minute stair climb (3MSC) and the level of urinary glycosaminoglycan (GAG) excretion. All patients received drug in an open-label extension period for an additional 24 weeks. RESULTS: After 24 weeks, patients receiving rhASB walked on average 92 meters (m) more in the 12MWT (p=.025) and 5.7 stairs per minute more 3MSC (p=.053) than patients receiving placebo. Continued improvement was observed during the extension study. Urinary GAG declined by -227+/-18 microg/mg more with rhASB than placebo (p<.001). Infusions were generally safe and well tolerated. Patients exposed to drug experienced positive clinical benefit despite the presence of antibody to the protein. CONCLUSION: rhASB significantly improves endurance, reduces GAG, and has an acceptable safety profile.

Direct comparison of measures of endurance, mobility, and joint function during enzyme-replacement therapy of mucopolysaccharidosis VI (Maroteaux-Lamy syndrome): results after 48 weeks in a phase 2 open-label clinical study of recombinant human N-acetylgalactosamine 4-sulfatase.

OBJECTIVE: Mucopolysaccharidosis VI (MPS VI; Maroteaux-Lamy syndrome) is a lysosomal storage disease caused by a deficiency of the enzyme N-acetylgalactosamine 4-sulfatase (ASB). This enzyme deficiency leads to a progressive disorder with multiple tissue and organ involvement. The disease is rare and is heterogeneous in its clinical presentation and progression. A potential treatment for this disease exists in the form of enzyme-replacement therapy (ERT) with recombinant human ASB (rhASB), and a phase 1/2 randomized, double-blind, 2-dose (0.2 and 1 mg/kg) study in 6 patients showed the treatment at 48 weeks to be well tolerated. Greater biochemical efficacy based on a urine glycosaminoglycan occurred in the high-dose (1 mg/kg) group, and functional improvement seemed greater in patients in the high-dose group with rapidly advancing disease. On the basis of the phase 1/2 results, a phase 2, open-label study in patients with rapidly advancing disease was initiated primarily to evaluate efficacy variables that measure endurance, mobility, and joint function in a larger group of patients. METHODS: This was an open-label, multinational study of 10 MPS VI patients who received 48 weekly intravenous treatments with 1.0 mg/kg rhASB and had assessments of biochemical and clinical responses at regular intervals. RESULTS: After 24 weeks of treatment, each patient on average experienced a 155-m (98%) improvement in the 12-minute walk, a 64-m (62%) improvement at the 6-minute time point of the 12-minute walk, and a 48-stair (110%) gain in the 3-minute stair climb versus the baseline mean values. Additional improvements after 48 weeks of treatment were observed, including mean values of 211 m (138%) in the 12-minute walk, 75 m (80%) at the 6-minute time point of the 12-minute walk, and 61-stair (147%) gain in the 3-minute stair climb versus the baseline mean values. Joint Pain and Stiffness Questionnaire scores improved by at least 50% by week 24 and were maintained at week 48, whereas there were only small improvements in active shoulder range of motion (<10 degrees ) and in the time taken to stand, walk, and turn starting from a seated position (Expanded Timed Get-Up and Go test). Improvement in pulmonary function based on forced vital capacity and forced expiratory volume at 1 minute in the absence of growth was observed in 3 of 6 patients, and the observed gains occurred in the 24- to 48-week treatment interval. A mean decrease of 76% in urinary excretion of glycosaminoglycans indicated that a satisfactory biochemical response was achieved and the ERT was well tolerated. CONCLUSIONS: The results suggest that a 12-minute walk extends the dynamic range of the conventional 6-minute walk and, along with the 3-minute stair climb, provide a robust approach to documenting the improvement in endurance in MPS VI patients who undergo ERT with rhASB.

Threshold effect of urinary glycosaminoglycans and the walk test as indicators of disease progression in a survey of subjects with Mucopolysaccharidosis VI (Maroteaux-Lamy syndrome).

A cross-sectional survey in individuals affected with the lysosomal storage disease Mucopolysaccharidosis VI (MPS VI) was conducted to establish demographics, urinary glycosaminoglycan (GAG) levels, and clinical progression of the disease. The survey evaluated 121 bona fide MPS VI-affected individuals over the age of 4 years from 15 countries across the Americas, Europe, and Australasia representing greater than 10% of the estimated world prevalence of the disease. A medical history, complete physical exam, urinary GAG determination, and assessment of several clinical measures related to physical endurance, pulmonary function, joint range of motion, strength, and quality of life were completed for each participant. Although a wide variation in clinical presentation was observed, several general findings were obtained reflecting progression of the disease. Impaired physical endurance, as measured by the distance achieved in a 6-min walk, could be demonstrated across all age groups of MPS VI-affected individuals. High urinary GAG values (>200 mug/mg creatinine) were associated with an accelerated clinical course comprised of age-adjusted short stature and low body weight, impaired endurance, compromised pulmonary function, and reduced joint range of motion. An unexpected result was the predominance of urinary GAG values <100 mug/mg creatinine for those participants over the age of 20 years. Pending the collection of longitudinal data, these results suggest that urinary GAG levels predict clinical morbidity, and longer-term survival is associated with urinary GAG levels below a threshold of 100 mug/mg creatinine.

Enzyme replacement therapy for mucopolysaccharidosis I: a randomized, double-blinded, placebo-controlled, multinational study of recombinant human alpha-L-iduronidase (laronidase).

OBJECTIVE: To confirm the efficacy and safety of recombinant human alpha-L-iduronidase (laronidase) in patients with mucopolysaccharidosis I (MPS I). STUDY DESIGN: This was a randomized, double-blinded, multinational study of 45 patients with MPS I administered 100 U/kg (0.58 mg/kg) laronidase, or placebo intravenously weekly for 26 weeks. The coprimary efficacy end points compared the median change from baseline to week 26 between groups in percentage of predicted normal forced vital capacity (FVC) and in 6-minute walk test (6MWT) distance through the use of the Wilcoxon rank sum test. RESULTS: The laronidase (n=22) and placebo (n=23) groups had similar baseline characteristics. After 26 weeks, patients receiving laronidase compared with placebo showed mean improvements of 5.6 percentage points in percent of predicted normal FVC (median, 3.0; P=.009) and 38.1 meters in 6MWT distance (median, 38.5; P=.066; P=.039, analysis of covariance). Laronidase also significantly reduced hepatomegaly and urinary glycosaminoglycans, and, in more severely affected patients, improved sleep apnea/hypopnea and shoulder flexion. Laronidase was well-tolerated. Nearly all patients receiving enzyme had development of IgG antibodies, without apparent clinical effects. CONCLUSIONS: In patients with MPS I, laronidase significantly improves respiratory function and physical capacity, reduces glycosaminoglycan storage, and has a favorable safety profile.