Efficacy of a Combination Therapy with Laronidase and Genistein in Treating Mucopolysaccharidosis Type I in a Mouse Model

Mucopolysaccharidosis type I (MPS I) is a lysosomal storage disorder caused by α-L-iduronidase deficiency. The standard treatment, enzyme replacement therapy with laronidase, has limited effectiveness in treating neurological symptoms due to poor blood-brain barrier penetration. An alternative is substrate reduction therapy using molecules, such as genistein, which crosses this barrier. This study evaluated the effectiveness of a combination of laronidase and genistein in a mouse model of MPS I. Over 12 weeks, MPS I and wild-type mice received laronidase, genistein, or both. Glycosaminoglycan (GAG) storage in visceral organs and the brain, its excretion in urine, and the serum level of the heparin cofactor II-thrombin (HCII-T) complex, along with behavior, were assessed. The combination therapy resulted in reduced GAG storage in the heart and liver, whereas genistein alone reduced the brain GAG storage. Laronidase and combination therapy decreased liver and spleen weights and significantly reduced GAG excretion in the urine. However, this therapy negated some laronidase benefits in the HCII-T levels. Importantly, the combination therapy improved the behavior of female mice with MPS I. These findings offer valuable insights for future research to optimize MPS I treatments.

Phenotypic characterisation of the Mucopolysaccharidosis Type I (MPSI) Idua-W392X mouse model reveals increased anxiety-related traits in female mice

Mucopolysaccharidosis Type I (MPSI) is a rare inherited lysosomal storage disease that arises due to mutations in the IDUA gene. Defective alpha-L-iduronidase (IDUA) enzyme is unable to break down glucosaminoglycans (GAGs) within the lysosomes and, as a result, there is systemic accumulation of undegraded products in lysosomes throughout the body leading to multi-system disease. Here, we characterised the skeletal/craniofacial, neuromuscular and behavioural outcomes of the MPSI Idua-W392X mouse model. We demonstrate that Idua-W392X mice have gross craniofacial abnormalities, showed signs of kyphosis, and show signs of hypoactivity compared to wild-type mice. X-ray imaging analysis revealed significantly shorter and wider tibias and femurs, significantly wider snouts, increased skull width and significantly thicker zygomatic arch bones in Idua-W392X female mice compared to wild-type mice at 9 and 10.5 months of age. Idua-W392X mice display decreased muscle strength, especially in the forelimbs, which is already apparent from 3 months of age. Female Idua-W392X mice display hypoactivity in the open-field test from 9 months of age and anxiety-like behaviour at 10 months of age. As these behaviours have been identified in Hurler children, the MPSI Idua-W392X mouse model may be important for the investigation of new therapeutic approaches for MPSI-Hurler.

Clinical and pathological characterization of ophthalmic disease in a canine model of mucopolysaccharidosis type I

Mucopolysaccharidosis type I (MPS I) is a rare lysosomal storage disease caused by α-L-iduronidase enzyme deficiency, resulting in glycosaminoglycan (GAG) accumulation in various cell types, including ocular tissues. Ocular manifestations in humans are common with significant pathological changes including corneal opacification, retinopathy, optic nerve swelling and atrophy, and glaucoma. Available treatments for MPS I are suboptimal and there is limited to no effect in treating the ocular disease. The goal of this study was to characterize the clinical and pathological features of ocular disease in a line of MPS I affected dogs, including changes not previously reported. A total of 22 dogs were studied; 12 MPS I were affected and 10 were unaffected. A subset of each underwent complete ophthalmic examination including slit lamp biomicroscopy, indirect ophthalmoscopy, rebound tonometry, and ultrasonic pachymetry. Globes were evaluated microscopically for morphological changes and GAG accumulation. Clinical corneal abnormalities in affected dogs included edema, neovascularization, fibrosis, and marked stromal thickening. Intraocular pressures were within reference interval for affected and unaffected dogs. Microscopically, vacuolated cells containing alcian blue positive inclusions were detected within the corneal stroma, iris, ciliary body, sclera, and optic nerve meninges of affected dogs. Ganglioside accumulation was identified by luxol fast blue staining in rare retinal ganglion cells. Increased lysosomal integral membrane protein-2 expression was demonstrated within the retina of affected animals when compared to unaffected controls. Results of this study further characterize ocular pathology in the canine model of MPS I and provide foundational data for future therapeutic efficacy studies.

Evaluation of non-reducing end pathologic glycosaminoglycan detection method for monitoring therapeutic response to enzyme replacement therapy in human mucopolysaccharidosis I

Therapeutic development and monitoring require demonstration of effects on disease phenotype. However, due to the complexity of measuring clinically-relevant effects in rare multisystem diseases, robust biomarkers are essential. For the mucopolysaccharidoses (MPS), the measurement of glycosaminoglycan levels is relevant as glycosaminoglycan accumulation is the primary event that occurs due to reduced lysosomal enzyme activity. Traditional dye-based assays that measure total glycosaminoglycan levels have a high background, due to a normal, baseline glycosaminoglycan content in unaffected individuals. An assay that selectively detects the disease-specific non-reducing ends of heparan sulfate glycosaminoglycans that remain undegraded due to deficiency of a specific enzyme in the catabolic pathway avoids the normal background, increasing sensitivity and specificity. We evaluated glycosaminoglycan content by dye-based and non-reducing end methods using urine, serum, and cerebrospinal fluid from MPS I human samples before and after treatment with intravenous recombinant human alpha-l-iduronidase. We found that both urine total glycosaminoglycans and serum heparan sulfate derived non-reducing end levels were markedly decreased compared to baseline after 26 weeks and 52 weeks of therapy, with a significantly greater percentage reduction in serum non-reducing end (89.8% at 26 weeks and 81.3% at 52 weeks) compared to urine total glycosaminoglycans (68.3% at 26 weeks and 62.4% at 52 weeks, p < 0.001). Unexpectedly, we also observed a decrease in non-reducing end levels in cerebrospinal fluid in all five subjects for whom samples were collected (mean 41.8% reduction, p = 0.01). The non-reducing ends in cerebrospinal fluid showed a positive correlation with serum non-reducing end levels in the subjects (r² = 0.65, p = 0.005). Results suggest utility of the non-reducing end assay in evaluating a therapeutic response in MPS I.

Intrathecal enzyme replacement for cognitive decline in mucopolysaccharidosis type I, a randomized, open-label, controlled pilot study

Central nervous system manifestations of mucopolysaccharidosis type I (MPS I) such as cognitive impairment, hydrocephalus, and spinal cord compression are inadequately treated by intravenously-administered enzyme replacement therapy with laronidase (recombinant human alpha-L-iduronidase). While hematopoietic stem cell transplantation treats neurological symptoms, this therapy is not generally offered to attenuated MPS I patients. This study is a randomized, open-label, controlled pilot study of intrathecal laronidase in eight attenuated MPS I patients with cognitive impairment. Subjects ranged between 12 years and 50 years old with a median age of 18 years. All subjects had received intravenous laronidase prior to the study over a range of 4 to 10 years, with a mean of 7.75 years. Weekly intravenous laronidase was continued throughout the duration of the study. The randomization period was one year, during which control subjects attended all study visits and assessments, but did not receive any intrathecal laronidase. After the first year, all eight subjects received treatment for one additional year. There was no significant difference in neuropsychological assessment scores between control or treatment groups, either over the one-year randomized period or at 18 or 24 months. However, there was no significant decline in scores in the control group either. Adverse events included pain (injection site, back, groin), headache, neck spasm, and transient blurry vision. There were seven serious adverse events, one judged as possibly related (headache requiring hospitalization). There was no significant effect of intrathecal laronidase on cognitive impairment in older, attenuated MPS I patients over a two-year treatment period. A five-year open-label extension study is underway.

Limited data to evaluate real-world effectiveness of enzyme replacement therapy for mucopolysaccharidosis type I

Orphan medicinal products (OMPs) are often authorized based on pivotal phase II and III trials that do not always meet high quality criteria. Laronidase is an example of an OMP used for treatment of mucopolysaccharidosis I (MPS I). One randomized controlled trial demonstrated efficacy on several somatic symptoms. However, effectiveness in the real-world setting remains to be determined. We performed a systematic review to evaluate the effectiveness of enzyme replacement therapy (ERT) on clinically relevant outcomes in MPS I. A search in OVID MEDLINE and OVID EMBASE was performed. Postmarketing studies including MPS I patients treated with ERT and reporting data on any of 19 predefined clinical outcome measures obtained before the start of ERT and at follow-up were eligible. Three scenarios were used to define effectiveness of ERT. The first scenario (A) assumes that improvement is essential, while the second scenario (B) also includes stabilization of signs and symptoms. The third scenario (C) defines failure of therapy. Twenty case series were included. The criteria indicating effectiveness (A), were met for four of 19 outcome measures while the criteria, indicating unclear effectiveness (B) were met for five of 19. For one of 19 nonverifiable data were reported and for nine of 19 no overall conclusions could be drawn (ambiguous results). Real-world effectiveness of laronidase is extremely difficult to assess, 15 years after marketing authorization. This is partially due to insufficient natural history data. We recommend the conduct of rigorous and independent postmarketing studies including core outcome sets for OMPs, enforced by marketing and/or reimbursing authorities aiming to demonstrate real-world effectiveness within a reasonable time frame.

Enzyme replacement therapy with laronidase (Aldurazyme®) for treating mucopolysaccharidosis type I

BACKGROUND

Mucopolysaccharidosis type I can be classified as three clinical sub-types; Hurler syndrome, Hurler-Scheie syndrome and Scheie syndrome, with the scale of severity being such that Hurler syndrome is the most severe and Scheie syndrome the least severe. It is a rare, autosomal recessive disorder caused by a deficiency of alpha-L-iduronidase. Deficiency of this enzyme results in the accumulation of glycosaminoglycans within the tissues. The clinical manifestations are facial dysmorphism, hepatosplenomegaly, upper airway obstruction, skeletal deformity and cardiomyopathy. If Hurler syndrome is left untreated, death ensues by adolescence. There are more attenuated variants termed Hurler-Scheie or Scheie syndrome, with those affected potentially not presenting until adulthood. Enzyme replacement therapy has been used for a number of years in the treatment of Hurler syndrome, although the current gold standard would be a haemopoietic stem cell transplant in those diagnosed by 2.5 years of age. This is an updated version of the original Cochrane Review published in 2013 and previously updated in 2015.

OBJECTIVES

To evaluate the effectiveness and safety of treating mucopolysaccharidosis type I with laronidase enzyme replacement therapy as compared to placebo.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Inborn Errors of Metabolism Trials Register, MEDLINE via OVID and Embase.Date of most recent search: 30 January 2019.

SELECTION CRITERIA

Randomised and quasi-randomised controlled studies of laronidase enzyme replacement therapy compared to placebo.

DATA COLLECTION AND ANALYSIS

Two authors independently screened the identified studies. The authors then appraised and extracted data. The quality of the evidence was assessed using GRADE.

MAIN RESULTS

One study (45 participants) met the inclusion criteria. This double-blind, placebo-controlled, randomised, multinational study looked at laronidase at a dose of 0.58 mg/kg/week versus placebo in people with mucopolysaccharidosis type I. All primary outcomes listed in this review were studied in this study. The laronidase group achieved statistically significant improvements in per cent predicted forced vital capacity compared to placebo, MD 5.60 (95% confidence intervals 1.24 to 9.96) (low-quality evidence) and in the six-minute-walk test (mean improvement of 38.1 metres in the laronidase group; P = 0.039, when using a prospectively planned analysis of covariance) (low-quality evidence). The levels of urinary glycoaminoglycans were also significantly reduced (low-quality evidence). In addition, there were improvements in hepatomegaly, sleep apnoea and hypopnoea. Laronidase antibodies were detected in nearly all participants in the treatment group with no apparent clinical effect and titres were reducing by the end of the study (very low-quality evidence). Infusion-related adverse reactions occurred in both groups but all were mild and none necessitated medical intervention or infusion cessation (low-quality evidence). As assessed by questionnaires,changes in a 'Disability Index' after treatment were small and did not differ between groups (low-quality evidence). There were no deaths in either group (low-quality evidence).

AUTHORS' CONCLUSIONS

The current evidence demonstrates that laronidase is effective when compared to placebo in the treatment of mucopolysaccharidosis type I. The included study was comprehensive, with few participants and of low quality. The study included all of the key outcome measures we wished to look at. It demonstrated that laronidase is efficacious in relation to reducing biochemical parameters (reduced urine glycosaminoglycan excretion) and improved functional capacity as assessed by forced vital capacity and the six-minute-walk test. In addition glycosaminoglycan storage was reduced as ascertained by a reduction in liver volume. Laronidase appeared to be safe and, while antibodies were generated, these titres were reducing by the end of the study. More studies are required to determine long-term effectiveness and safety and to assess the impact upon quality of life. Enzyme replacement therapy with laronidase can be used pre- and peri-haemopoietic stem cell transplant, which is now the gold standard treatment in those individuals diagnosed under 2.5 years of age. We do not anticipate any further trials to be undertaken and therefore do not plan to update this review.

Agreement between the results of meta-analyses from case reports and from clinical studies regarding the efficacy of laronidase therapy in patients with mucopolysaccharidosis type I who initiated enzyme replacement therapy in adult age: An example of case reports meta-analyses as an useful tool for evidence-based medicine in rare diseases

BACKGROUND

Case reports might have a prominent role in the rare diseases field, due to the small number of patients affected by one such disease. A previous systematic review regarding the efficacy of laronidase therapy in patients with mucopolysaccharidosis type I (MPS-I) who initiated enzyme replacement therapy (ERT) in adult age has been published. The review included a meta-analysis of 19 clinical studies and the description of eleven case reports. It was of interest to perform a meta-analysis of those case reports to explore the role of such meta-analyses as a tool for evidence-based medicine in rare diseases.

METHODS

The study included all case reports with standard treatment regimen. Primary analysis was the percentage of case reports showing an improvement in a specific outcome. Only when that percentage was statistically higher than 5%, the improvement was confirmed as such. The outcomes that accomplished this criterion were ranked and compared to the GRADE criteria obtained by those same outcomes in the previous meta-analysis of clinical studies.

RESULTS

There were three outcomes that had a significant improvement: Urine glycosaminoglycans, liver volume and 6-minute walking test. Positive and negative predictive values, sensitivity and specificity for the results of the meta-analysis of case reports as compared to that of clinical studies were 100%, 88.9%, 75% and 100%, respectively. Accordingly, absolute (Rho=0.82, 95%CI: 0.47 to 0.95) and relative agreement (Kappa=0.79, 95%CI: 0.593 to 0.99) between the number of case reports with improvement in a specific outcome and the GRADE evidence score for that outcome were good. Sensitivity analysis showed that agreement between the meta-analysis of case reports and that of the clinical studies were good only when using a strong confirmatory strategy for outcome improvement in case reports.

CONCLUSIONS

We found an agreement between the results of meta-analyses from case reports and from clinical studies in the efficacy of laronidase therapy in patients with MPS-I who initiated ERT in adult age. This agreement suggests that combining case reports quantitatively, rather than analyzing them separately or qualitatively, may improve conclusions in the field of rare diseases.

Efficacy and safety of intravenous laronidase for mucopolysaccharidosis type I: A systematic review and meta-analysis

Mucopolysaccharidosis type I (MPS I) is an autosomal recessive disease caused by deficient activity of alpha-L-iduronidase. Intravenous (IV) enzyme replacement therapy (ERT) with laronidase is currently used for treating patients with MPS I.

Efficacy of laronidase therapy in patients with mucopolysaccharidosis type I who initiated enzyme replacement therapy in adult age. A systematic review and meta-analysis

BACKGROUND

The efficacy of starting enzyme replacement therapy (ERT) in adults with Muchopolysaccharidosis Type I (MPS-I) is controversial. Evaluating the benefits reported by patients initiating ERT with laronidase at adult age might help physicians decide whether the use of ERT in these patients is worthwhile from a clinical point of view.

OBJECTIVE

To assess every effectiveness variable modified in MPS-I patients who initiated laronidase at adult age.

METHODS

A systematic search of the literature, from inception to July 2016, was conducted using MEDLINE, EMBASE, CENTRAL and LILACS to identify randomized trials or observational studies including ≥1 MPS-I patients with ERT initiated in adult age (≥18years) and evaluating ERT efficacy. A meta-analysis of studies evaluating the same effectiveness outcome was performed and the evidence was rated according to GRADE criteria. Heterogeneity was assessed by the Chi-squared test and the I-squared statistic. Case reports were excluded from meta-analysis but their main outcomes were separately evaluated. The decrease in urine glycosaminoglycans (uGAGs) levels as patient percentage with reduction in uGAGs and with normalization was the primary outcome.

RESULTS

Nineteen clinical studies and 12 case reports were selected. ERT decreased uGAG levels (high evidence) and liver volume (high), improved 6-min walking test (6MWT) (moderate) and increased blood anti-ERT antibody levels (high). There was no conclusive results (low or very low evidence) regarding improvement/stabilization of respiratory function, change in shoulder flexion, cardiac improvement/stabilization, improvement in symptoms of nocturnal hypoventilation and sleep apnea, improvement in quality of life, visual acuity, otolaryngologic function, bone mineral density or effectiveness of intrathecal therapy.

LIMITATIONS

Excluding case reports, there was no study conducted specifically in the target population (ERT ≥18years). Data were from subgroup analyses of selected studies. There was a great heterogeneity between designs and clinical outcomes evaluated.

CONCLUSIONS

ERT improves uGAGs and liver volume in MPS-I patients initiating therapy as adults, although the putative clinical benefit associated to these improvements is unclear. Moderate evidence was shown for improvement in 6MWT. Systematic review registration number (PROSPERO): 42,016,041,306.

Neonatal tolerance induction enables accurate evaluation of gene therapy for MPS I in a canine model

High fidelity animal models of human disease are essential for preclinical evaluation of novel gene and protein therapeutics. However, these studies can be complicated by exaggerated immune responses against the human transgene. Here we demonstrate that dogs with a genetic deficiency of the enzyme α-l-iduronidase (IDUA), a model of the lysosomal storage disease mucopolysaccharidosis type I (MPS I), can be rendered immunologically tolerant to human IDUA through neonatal exposure to the enzyme. Using MPS I dogs tolerized to human IDUA as neonates, we evaluated intrathecal delivery of an adeno-associated virus serotype 9 vector expressing human IDUA as a therapy for the central nervous system manifestations of MPS I. These studies established the efficacy of the human vector in the canine model, and allowed for estimation of the minimum effective dose, providing key information for the design of first-in-human trials. This approach can facilitate evaluation of human therapeutics in relevant animal models, and may also have clinical applications for the prevention of immune responses to gene and protein replacement therapies.

Enzyme replacement therapy with laronidase (Aldurazyme(®)) for treating mucopolysaccharidosis type I

BACKGROUND

Mucopolysaccharidosis type I can be classified as three clinical sub-types; Hurler syndrome, Hurler-Scheie syndrome and Scheie syndrome, with the scale of severity being such that Hurler syndrome is the most severe and Scheie syndrome the least severe. It is a rare, autosomal recessive disorder caused by a deficiency of alpha-L-iduronidase. Deficiency of this enzyme results in the accumulation of glycosaminoglycans within the tissues. The clinical manifestations are facial dysmorphism, hepatosplenomegaly, upper airway obstruction, skeletal deformity and cardiomyopathy. If Hurler syndrome is left untreated, death ensues by adolescence. There are more attenuated variants termed Hurler-Scheie or Scheie syndrome, with those affected potentially not presenting until adulthood. Enzyme replacement therapy has been used for a number of years in the treatment of Hurler syndrome, although the current gold standard would be a haemopoietic stem cell transplant in those diagnosed by 2.5 years of age. This is an updated version of the original Cochrane review published in 2013.

OBJECTIVES

To evaluate the effectiveness and safety of treating mucopolysaccharidosis type I with laronidase enzyme replacement therapy as compared to placebo.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Inborn Errors of Metabolism Trials Register, MEDLINE via OVID and Embase.Date of most recent search: 05 October 2015.

SELECTION CRITERIA

Randomised and quasi-randomised controlled studies of laronidase enzyme replacement therapy compared to placebo.

DATA COLLECTION AND ANALYSIS

Two authors independently screened the identified studies. The authors then appraised and extracted data.

MAIN RESULTS

One study of 45 patients met the inclusion criteria. This double-blind, placebo-controlled, randomised, multinational study looked at laronidase at a dose of 0.58 mg/kg/week versus placebo in patients with mucopolysaccharidosis type I. All primary outcomes listed in this review were studied in this study. The laronidase group achieved statistically significant improvements in per cent predicted forced vital capacity compared to placebo, MD 5.60 (95% confidence intervals 1.24 to 9.96) and in the six-minute-walk test (mean improvement of 38.1 metres in the laronidase group; P = 0.039, when using a prospectively planned analysis of covariance). The levels of urinary glycoaminoglycans were also significantly reduced. In addition, there were improvements in hepatomegaly, sleep apnoea and hypopnoea. Laronidase antibodies were detected in nearly all patients in the treatment group with no apparent clinical effect and titres were reducing by the end of the study. Infusion-related adverse reactions occurred in both groups but all were mild and none necessitated medical intervention or infusion cessation.

AUTHORS' CONCLUSIONS

The current evidence demonstrates that laronidase is effective when compared to placebo in the treatment of mucopolysaccharidosis type I. The included study was comprehensive and of good quality, although there were few participants. The study included all of the key outcome measures we wished to look at. It demonstrated that laronidase is efficacious in relation to reducing biochemical parameters (reduced urine glycosaminoglycan excretion) and improved functional capacity as assessed by forced vital capacity and the six-minute-walk test. In addition glycosaminoglycan storage was reduced as ascertained by a reduction in liver volume. Laronidase appeared to be safe and, while antibodies were generated, these titres were reducing by the end of the study. More studies are required to determine long-term effectiveness and safety and to assess the impact upon quality of life. Enzyme replacement therapy with laronidase can be used pre- and peri-haemopoietic stem cell transplant, which is now the gold standard treatment in those patients diagnosed under 2.5 years of age.

Effect of anti-laronidase antibodies on efficacy and safety of laronidase enzyme replacement therapy for MPS I: A comprehensive meta-analysis of pooled data from multiple studies

Enzyme replacement therapy (ERT) with laronidase has an important role in the treatment of patients with mucopolysaccharidosis type I (MPS I). Laronidase is safe and has demonstrated effectiveness in terms of stabilizing or improving conventional clinical and laboratory markers of the disease. However, like most ERTs, laronidase produces an anti-drug IgG antibody response in more than 90% of patients during the first few months of treatment. Preclinical data from the MPS I canine model suggest that anti-drug antibodies (ADA) impair enzyme uptake in target tissues. In patients, the effects on tissue glycosaminoglycan (GAG) clearance are difficult to assess directly but data from clinical studies have suggested an association between ADA and both a reduced pharmacodynamic response and hypersensitivity reactions. This comprehensive meta-analysis of pooled data from patients in three clinical studies of laronidase (including one study with an extension) was undertaken to provide a more robust assessment of the relationship between the ADA response to laronidase, clinical and laboratory markers of MPS I, and hypersensitivity reactions. The meta-analysis demonstrated an inverse relationship between the ADA response and the percent reduction in urinary GAG (uGAG) levels. However, no relationships between the ADA response and changes in percent predicted forced vital capacity and six-minute walk test were seen. The study also re-assayed stored serum samples from the original trials with a novel method to determine the inhibitory effect of ADA. Patients with higher ADA exposure over time were found to have higher inhibition of enzyme uptake into cells. High ADA exposure can result in a commensurate level of enzyme uptake inhibition that decreases the pharmacodynamic effect of the exogenously administered therapeutic enzyme, but with no clear effect on clinical efficacy.

A method for measuring disease-specific iduronic acid from the non-reducing end of glycosaminoglycan in mucopolysaccharidosis type II mice

Mucopolysaccharidosis type II (MPS II) is an X-linked lysosomal storage disorder arising from deficiency of iduronate-2-sulfatase (IDS), which results in progressive accumulation of glycosaminoglycans (GAGs) in multiple tissues. Accumulated GAGs are generally measured as the amount of total GAGs. However, we recently demonstrated that GAG accumulation in the brain of MPS II model mice cannot be reliably detected by conventional dye-binding assay measuring total GAGs. Here we developed a novel quantitative method for measurement of disease-specific GAGs based on the analysis of 2-sulfoiduronic acid levels derived from the non-reducing terminal end of the polysaccharides by using recombinant human IDS (rhIDS) and recombinant human iduronidase (rhIDUA). This method was evaluated on GAGs obtained from the liver and brain of MPS II mice. The GAGs were purified from tissue homogenates and then digested with rhIDS and rhIDUA to generate a desulfated iduronic acid from their non-reducing terminal end. HPLC analysis revealed that the generated iduronic acid levels were markedly increased in the liver and cerebrum of the MPS II mice, whereas the uronic acid was not detected in wild-type mice. These results indicate that this assay clearly detects the disease-specific GAGs in tissues from MPS II mice.

Safety of laronidase delivered into the spinal canal for treatment of cervical stenosis in mucopolysaccharidosis I

Enzyme replacement therapy with laronidase (recombinant human alpha-l-iduronidase) is successfully used to treat patients with mucopolysaccharidosis type I (MPS I). However, the intravenously-administered enzyme is not expected to treat or prevent neurological deterioration. As MPS I patients suffer from spinal cord compression due in part to thickened spinal meninges, we undertook a phase I clinical trial of lumbar intrathecal laronidase in MPS I subjects age 8 years and older with symptomatic (primarily cervical) spinal cord compression. The study faced significant challenges, including a heterogeneous patient population, difficulty recruiting subjects despite an international collaborative effort, and an inability to include a placebo-controlled design due to ethical concerns. Nine serious adverse events occurred in the subjects. All subjects reported improvement in symptomatology and showed improved neurological examinations, but objective outcome measures did not demonstrate change. Despite limitations, we demonstrated the safety of this approach to treating neurological disease due to MPS I.

Activities of daily living in patients with Hunter syndrome: impact of enzyme replacement therapy and hematopoietic stem cell transplantation

The aim of this study was to assess the activities of daily living (ADL) in patients with Hunter syndrome (mucopolysaccharidosis II; MPS II) using a newly designed ADL questionnaire. We applied the questionnaire to evaluate clinical phenotypes and therapeutic efficacies of enzyme replacement therapy (ERT) and hematopoietic stem cell transplantation (HSCT). We also explored early signs and symptoms to make early diagnosis feasible. We devised a new ADL questionnaire with three domains: "movement," "movement with cognition," and "cognition." Each domain has four subcategories rated on a 5-point scale based on level of assistance. We also scored signs and symptoms unique to MPS by 12 subcategories (five points per category), providing 60 points in total. The questionnaire was first administered to 138 healthy Japanese controls (0.33-50 years), and successively, to 74 Japanese patients with Hunter syndrome (4-49 years). The patient cohort consisted of 51 severe and 23 attenuated phenotypes; 20 patients treated with HSCT, 23 patients treated early with ERT (≤8 years), 25 patients treated late with ERT (>8 years), and 4 untreated patients. Among 18 severe phenotypic patients treated by HSCT, 10 were designated as early HSCT (≤5years), while 8 were designated as late HSCT (>5years). Scores from patients with severe phenotypes were lower than controls and attenuated phenotypes in all categories. Among patients with severe phenotypes, there was a trend that HSCT provides a higher ADL score than early ERT, and there was a significant difference in ADL scores between late ERT and HSCT groups. Early ERT and early HSCT provided a higher score than late ERT and late HSCT, respectively. In conclusion, we have evaluated the feasibility of a new questionnaire in control population and patients with Hunter syndrome, leading to a novel evaluation method for clinical phenotypes and therapeutic efficacy. Early treatment with HSCT provides a better consequence in ADL of patients.

Biomarker responses correlate with antibody status in mucopolysaccharidosis type I patients on long-term enzyme replacement therapy

BACKGROUND

Antibody formation can interfere with effects of enzyme replacement therapy (ERT) in lysosomal storage diseases. Biomarkers are used as surrogate marker for disease burden in MPS I, but large systematic studies evaluating the response of biomarkers to ERT are lacking. We, for the first time, investigated the response of a large panel of biomarkers to long term ERT in MPS I patients and correlate these responses with antibody formation and antibody mediated cellular uptake inhibition.

METHODS

A total of 428 blood and urine samples were collected during long-term ERT in 24 MPS I patients and an extensive set of biomarkers was analyzed, including heparan sulfate (HS) and dermatan sulfate (DS) derived disaccharides; total urinary GAGs (DMBu); urinary DS:CS ratio and serum heparin co-factor II thrombin levels (HCII-T). IgG antibody titers and the effect of antibodies on cellular uptake of the enzyme were determined for 23 patients.

RESULTS

Median follow-up was 2.3 years. In blood, HS reached normal levels more frequently than DS (50% vs 12.5%, p=0.001), though normalization could take several years. DMBu normalized more rapidly than disaccharide levels in urine (p=0.02). Nineteen patients (83%) developed high antibody titers. Significant antibody-mediated inhibition of enzyme uptake was observed in 8 patients (35%), and this correlated strongly with a poorer biomarker response for HS and DS in blood and urine as well as for DMBu, DS:CS-ratio and HCII-T (all p<0.006).

CONCLUSIONS

This study shows that, despite a response of all studied biomarkers to initiation of ERT, some biomarkers were less responsive than others, suggesting residual disease activity. In addition, the correlation of cellular uptake inhibitory antibodies with a decreased biomarker response demonstrates a functional role of these antibodies which may have important clinical consequences.

Mucopolysaccharidosis type I

Mucopolysaccharidosis type I (MPS I) is caused by a deficiency of the lysosomal hydrolase a-L-Iduronidase leading to accumulation of the GAGs, dermatan sulfate, and heparan sulphate, The disease spectrum includes a disorder with severe involvement and CNS disease Hurler disease (HPS I H) a chronic disease without CNS disease Scheie disease (HPS I S5) and the intermediate Hurler/Scheie disease(HPS I HIS).The urine GAGs pattern. confirmed by Iduronidase enzyme assay is diagnostic. Over 200 mutations exist. Genotype / phenotype correlation is poor but two nonsense mutations results in Hurler disease.The skeletal disease dysostosis multiplex (DM) is seen in severe variants of MPS I. The hypoplastic odontoid putting these patients at high risk of cervical cord damage. MPS IH (Hurler Disease) affected infants develop a spinal 'gibbus' deformity, persistent nasal discharge, middle ear effusions and frequent upper respiratory infection. They have "coarse", facial features, and an enlarged tongue. . Progressive upper airway disease leads to obstructive sleep apnoea. Corneal clouding and cognitive impairment appears, growth ceases. Joint stiffness and contractures limit mobility. Cardiac disease is universal. Death occurs before 10 years. SCHEIE patients are diagnosed as teenagers with hepatomegaly, joint contractures, cardiac valve abnormalities and corneal clouding . Prolonged survival with considerable disability without cognitive impairment is usual. MPS IH/S Hurler/Scheie. is diagnosed by 6.5 years, with variable skeletal and visceral manifestations without cognitive involvement. Joint stiffness, corneal clouding, , umbilical hernia, abnormal facies, hepatomegaly, joint contractures, and cervical myelopathy occur. Patients die in their 20s .Haematopoietic stem cell transplantation (HSCT) the standard treatment of MPS IH for 30 years is unpredictable .When performed before 2 years it can stabilize cognitive impairment. Hepatosplenomegaly, urine GAGs excretion, upper airways obstruction and cardiomyopathy improve . The coarse hair and facial features soften and corneas partly clear,but dysostosis multiplex and cervical instability are not improved. Enzyme replacement therapy (ERT) in patients with MPS IH is associated with improved GAG excretion, left ventricular hypertrophy,sleep studies and liver size. The standard treatment of MPS IHIS and MIPS IS is ERT a-L-Iduronidase, laronidase, a life-long therapy. GAG excretion is reduced, respiratory function and physical endurance improve. Joint mobility improves but not dural thickening, cardiac valve lesions or eye changes. MPS I mice have been successfully treated with IDUA-expressing mesenchymaf stem cells . Gene therapy may be developed for MPS I, via an ex vivo approach demonstrated to improve even skeletal outcomes in animal models.

Intra-articular enzyme replacement therapy with rhIDUA is safe, well-tolerated, and reduces articular GAG storage in the canine model of mucopolysaccharidosis type I

BACKGROUND

Treatment with intravenous enzyme replacement therapy and hematopoietic stem cell transplantation for mucopolysaccharidosis (MPS) type I does not address joint disease, resulting in persistent orthopedic complications and impaired quality of life. A proof-of-concept study was conducted to determine the safety, tolerability, and efficacy of intra-articular recombinant human iduronidase (IA-rhIDUA) enzyme replacement therapy in the canine MPS I model.

METHODS

Four MPS I dogs underwent monthly rhIDUA injections (0.58 mg/joint) into the right elbow and knee for 6 months. Contralateral elbows and knees concurrently received normal saline. No intravenous rhIDUA therapy was administered. Monthly blood counts, chemistries, anti-rhIDUA antibody titers, and synovial fluid cell counts were measured. Lysosomal storage of synoviocytes and chondrocytes, synovial macrophages and plasma cells were scored at baseline and 1 month following the final injection.

RESULTS

All injections were well-tolerated without adverse reactions. One animal required prednisone for spinal cord compression. There were no clinically significant abnormalities in blood counts or chemistries. Circulating anti-rhIDUA antibody titers gradually increased in all dogs except the prednisone-treated dog; plasma cells, which were absent in all baseline synovial specimens, were predominantly found in synovium of rhIDUA-treated joints at study-end. Lysosomal storage in synoviocytes and chondrocytes following 6 months of IA-rhIDUA demonstrated significant reduction compared to tissues at baseline, and saline-treated tissues at study-end. Mean joint synovial GAG levels in IA-rhIDUA joints were 8.62 ± 5.86 μg/mg dry weight and 21.6 ± 10.4 μg/mg dry weight in control joints (60% reduction). Cartilage heparan sulfate was also reduced in the IA-rhIDUA joints (113 ± 39.5 ng/g wet weight) compared to saline-treated joints (142 ± 56.4 ng/g wet weight). Synovial macrophage infiltration, which was present in all joints at baseline, was abolished in rhIDUA-treated joints only.

CONCLUSIONS

Intra-articular rhIDUA is well-tolerated and safe in the canine MPS I animal model. Qualitative and quantitative assessments indicate that IA-rhIDUA successfully reduces tissue and cellular GAG storage in synovium and articular cartilage, including cartilage deep to the articular surface, and eliminates inflammatory macrophages from synovial tissue.

CLINICAL RELEVANCE

The MPS I canine IA-rhIDUA results suggest that clinical studies should be performed to determine if IA-rhIDUA is a viable approach to ameliorating refractory orthopedic disease in human MPS I.

Does early use of enzyme replacement therapy alter the natural history of mucopolysaccharidosis I? Experience in three siblings

Enzyme replacement therapy is widely used as treatment for mucopolysaccharidosis I (MPS I), and there is evidence that this produces improvement in certain clinical domains. There does appear to be variation in the response of clinical features to treatment once these are established. In a reported sibling pair, when enzyme replacement therapy was commenced pre-symptomatically in the younger child, the natural history of the condition appeared to be affected. We present data from three siblings treated with enzyme replacement therapy at different ages which supports this finding.

Features of brain MRI in dogs with treated and untreated mucopolysaccharidosis type I

The mucopolysaccharidosis type I (MPS I) dog model has been important in the development of therapies for human patients. We treated dogs with enzyme replacement therapy (ERT) by various approaches. Dogs assessed included untreated MPS I dogs, heterozygous carrier dogs, and MPS I dogs treated with intravenous ERT as adults (beginning at age 13 to 16 mo), intrathecal and intravenous ERT as adults (beginning at age 13 to 16 mo), or intrathecal ERT as juveniles (beginning at age 4 mo). We then characterized the neuroimaging findings of 32 of these dogs (age, 12 to 30 mo). Whole and midsagittal volumes of the corpus callosum, measured from brain MRI, were significantly smaller in affected dogs compared with unaffected heterozygotes. Corpus callosum volumes in dogs that were treated with intrathecal ERT from 4 mo until 21 mo of age were indistinguishable from those of age-matched carrier controls. Dogs with MPS I showed cerebral ventricular enlargement and cortical atrophy as early as 12 mo of age. Ventricular enlargement was greater in untreated MPS I dogs than in age-matched dogs treated with intrathecal ERT as juveniles or adults. However, treated dogs still showed some ventricular enlargement or cortical atrophy (or both). Understanding the progression of neuroimaging findings in dogs with MPS I and their response to brain-directed therapy may improve preclinical studies for new human-directed therapies. In particular, corpus callosum volumes may be useful quantitative neuroimaging markers for MPS-related brain disease and its response to therapy.

Long-term efficacy of hematopoietic stem cell transplantation on brain involvement in patients with mucopolysaccharidosis type II: a nationwide survey in Japan

Hematopoietic stem cell transplantation (HSCT) has not been indicated for patients with mucopolysaccharidosis II (MPS II, Hunter syndrome), while it is indicated for mucopolysaccharidosis I (MPS I) patients <2 years of age and an intelligence quotient (IQ) of ≥ 70. Even after the approval of enzyme replacement therapy for both of MPS I and II, HSCT is still indicated for patients with MPS I severe form (Hurler syndrome). To evaluate the efficacy and benefit of HSCT in MPS II patients, we carried out a nationwide retrospective study in Japan. Activities of daily living (ADL), IQ, brain magnetic resonance image (MRI) lesions, cardiac valvular regurgitation, and urinary glycosaminoglycan (GAG) were analyzed at baseline and at the most recent visit. We also performed a questionnaire analysis about ADL for an HSCT-treated cohort and an untreated cohort (natural history). Records of 21 patients were collected from eight hospitals. The follow-up period in the retrospective study was 9.6 ± 3.5 years. ADL was maintained around baseline levels. Cribriform changes and ventricular dilatation on brain MRI were improved in 9/17 and 4/17 patients, respectively. Stabilization of brain atrophy was shown in 11/17 patients. Cardiac valvular regurgitation was diminished in 20/63 valves. Urinary GAG concentration was remarkably lower in HSCT-treated patients than age-matched untreated patients. In the questionnaire analysis, speech deterioration was observed in 12/19 patients in the untreated cohort and 1/7 patient in HSCT-treated cohort. HSCT showed effectiveness towards brain or heart involvement, when performed before signs of brain atrophy or valvular regurgitation appear. We consider HSCT is worthwhile in early stages of the disease for patients with MPS II.

[Mucopolysaccharidosis I: management and follow up of three patients]

Mucopolysaccharidosis type I or mucopolisacaridosis type I is a rare genetic disease, with a severe and fast multiorganic damage profile and fatal prognosis in the early years of age. It belongs to the lysosomal storage diseases (LSD) group pathologies. As an LSD, mucopolisacaridosis type I is due to the lack of the α-L-iduronidase enzyme. Enzyme replacement therapy (ERT) with laronidase is an effective treatment choice. It is available in Mexico since 2005. In the Hospital UMAE 25 of the Mexican Institute of Social Security (IMSS) in Monterrey, Nuevo Leon, Mexico, three patients have been treated and followed since 2006, with a close surveillance on their clinical evolution. The ERT with laronidase is expensive, relatively new and with little experience in Mexico, so there is a real need of knowing clinical evolution as well as overall treatment efficacy from baseline pre-treatment stage to date. Data on physical, functional and biochemical changes in these patients is presented.

[Mental retardation revealing mucopolysaccharidosis type I in a child treated for cystic fibrosis: a case report]

Mucopolysaccharidosis I (MPS I) is a lysosomal storage disease due to an α-L-iduronidase deficiency, which leads to an accumulation of glycosaminoglycans in the lysosomes of most cells, resulting in tissue and organ dysfunction. MPS I is inherited in an autosomal-recessive manner. This disorder has a chronic, progressive course and is characterized by mental retardation, dysmorphy, organomegaly, multisystem involvement, and multiple dysostosis. Early disease recognition is important for a prompt start of specific treatment, which improves many aspects of MPS I, and for the patient's overall management.

Clinical manifestations and treatment of mucopolysaccharidosis type I patients in Latin America as compared with the rest of the world

BACKGROUND

Mucopolysaccharidosis I (MPS I) comprises a spectrum of clinical manifestations and is divided into three phenotypes reflecting clinical severity: Hurler, Hurler-Scheie, and Scheie syndromes. There may be important variations in clinical manifestations of this genetic disease in patients residing in different regions of the world.

METHODS

Using data from the MPS I Registry (as of September 2009), we evaluated patients from Latin America (n = 118) compared with patients from the rest of the world [ROW (n = 727)].

RESULTS

Phenotype distribution differed among patients in Latin America compared to ROW (Hurler 31 vs. 62%, Hurler-Scheie 36 vs. 21%, Scheie 10 vs. 11%, and unknown 22 vs. 6%). The frequency of certain symptoms, such as cardiac valve abnormalities, sleep impairment, and joint contractures, also differed between Latin America and ROW for some phenotypes. Median age at MPS I diagnosis was earlier in the ROW than Latin America for all phenotypes, and age at first treatment for Hurler and Hurler-Scheie patients was also earlier in the ROW. Hurler patients in Latin America showed a gap of 3.1 years between median ages of diagnosis and first treatment compared to only 0.5 years in the ROW. Treatment allocation in Latin America compared to ROW was as follows: enzyme replacement therapy (ERT) only, 80 vs. 45%; hematopoietic stem cell transplantation (HSCT) only, 0.9 vs. 27%; both ERT and HSCT, 0 vs. 16%; and neither treatment, 19 vs. 13%.

CONCLUSION

These data highlight important differences in MPS I patients between Latin America and ROW in terms of phenotypic distribution, clinical manifestations, and treatment practices.

Laronidase replacement therapy improves myocardial function in mucopolysaccharidosis I

We assessed whether laronidase (recombinant human α-L-iduronidase) replacement therapy could improve left ventricular (LV) myocardial function in a 49-year-old woman with mucopolysaccharidosis I (MPS I) and valvular heart disease. After 6 months of laronidase treatment, the concentration of urinary uron acid decreased by 78.8%. Hepatosplenomegaly improved and LV weight decreased by 19.6%. LV ejection fraction assessed by two-dimensional echocardiogram did not change after laronidase treatment. However, in two-dimensional ultrasound speckle tracking imaging method, LV myocardial longitudinal strain (shortening ratio) increased from -13.2 to -17.4%. LV myocardial radial strain (thickening ratio) increased from 26.6 to 83.4%. LV myocardial torsion increased from +6 to +18°. These indexes of myocardial function were normalized after laronidase treatment. Thus, our findings were a first report that laronidase treatment had a beneficial effect on LV myocardial function in an adult patient with MPS I.

Combined Hurler and Sanfilippo syndrome in a sibling pair

The mucopolysaccharidoses (MPS) are lysosomal storage disorders caused by defects in the enzymes involved in the degradation of glycosaminoglycans. Hurler syndrome (MPS I) and Sanfilippo syndrome (MPS III) are among the more common diseases in the group, each occurring with an incidence of approximately 1 in 100,000. We present a case of siblings, born of a consanguineous union, affected with both MPS I and MPS IIIa. The diagnoses were confirmed with fibroblast enzyme assays and sequence analysis of the genes, which identified homozygous mutations in IDUA and SGSH. We discuss their clinical features and course and examine the psychosocial aspects of their case, specifically, the decision-making process that the medical team and family faced regarding treatment with enzyme replacement therapy.

Ethical issues related to the access to orphan drugs in Brazil: the case of mucopolysaccharidosis type I

BACKGROUND/AIMS

Mucopolysaccharidosis type I (MPS I) is a rare lysosomal storage disorder treated with bone marrow transplantation or enzyme replacement therapy with laronidase, a high-cost orphan drug. Laronidase was approved by the US Food and Drug Administration and the European Medicines Agency in 2003 and by the Brazilian National Health Surveillance Agency in 2005. Many Brazilian MPS I patients have been receiving laronidase despite the absence of a governmental policy regulating access to the drug. Epidemiological and treatment data concerning MPS I are scarce. This study aims to present a demographic profile of Brazilian patients with MPS I, describe the routes of access to laronidase in Brazil, and discuss associated ethical issues relating to public funding of orphan drugs.

METHODS

In this cross-sectional observational study, data were collected nationwide between January and September 2008 from physicians, public institutions and non-governmental organisations involved with diagnosis and treatment of MPS I, using two data collection instruments specifically designed for this purpose.

RESULTS

The minimum prevalence of MPS I in Brazil was estimated at 1/2,700,000. Most patients (69.8%) were younger than 15 years; 60 (88.2%) received laronidase. The most common route of access to the drug was through lawsuits (86.6%).

CONCLUSIONS

In Brazil, MPS I is predominantly a paediatric illness. Even though the cost of laronidase treatment is not officially covered by the Brazilian government, most MPS I patients receive the drug, usually through litigation. This gives rise to major ethical conflicts concerning drug access in a low-resource context. The Brazilian health policy framework lacks evidence-based clinical protocols for the distribution of orphan drugs.

Sudden vision loss in a mucopolysaccharidosis I patient receiving enzyme replacement therapy

A 25-year-old female was referred for short stature and joint deformities. Except for previous corneal transplantation, her medical history was unremarkable. Initial physical examination revealed the presence of a coarse facies, short neck, kyphosis, restricted joint movements and deformities, and cardiac murmur besides a normal intellect. Urine glycosaminoglycan levels were high, and blood enzyme assay indicated significantly low alpha-L-iduronidase levels. Mucopolysaccharidosis I (MPS I) was diagnosed and prompted the onset of enzyme replacement therapy (ERT), which significantly improved articular complaints, while cardiac pathology remained stable. At the eighteenth month of ERT, sudden vision loss developed. She spontaneously recovered her vision in a month. MPS I is a progressive disease, in which tissue accummulation of heparan and dermatan sulphate result from defective activity or lack of alpha-L-iduronidase. ERT in MPS I usually presents favourable outcomes or at least stabilization of symptoms. This present case qualifies as the first report ofa MPS I patient developing sudden vision loss under ERT. We suggest that further research studies are warranted for defining the efficiency and possible limitations of ERT.

Early versus late treatment of spinal cord compression with long-term intrathecal enzyme replacement therapy in canine mucopolysaccharidosis type I

Enzyme replacement therapy (ERT) with intravenous recombinant human alpha-l-iduronidase (IV rhIDU) is a treatment for patients with mucopolysaccharidosis I (MPS I). Spinal cord compression develops in MPS I patients due in part to dural and leptomeningeal thickening from accumulated glycosaminoglycans (GAG). We tested long-term and every 3-month intrathecal (IT) and weekly IV rhIDU in MPS I dogs age 12-15months (Adult) and MPS I pups age 2-23days (Early) to determine whether spinal cord compression could be reversed, stabilized, or prevented. Five treatment groups of MPS I dogs were evaluated (n=4 per group): IT+IV Adult, IV Adult, IT + IV Early, 0.58mg/kg IV Early and 1.57mg/kg IV Early. IT + IV rhIDU (Adult and Early) led to very high iduronidase levels in cervical, thoracic, and lumber spinal meninges (3600-29,000% of normal), while IV rhIDU alone (Adult and Early) led to levels that were 8.2-176% of normal. GAG storage was significantly reduced from untreated levels in spinal meninges of IT + IV Early (p<.001), IT+IV Adult (p=.001), 0.58mg/kg IV Early (p=.002) and 1.57mg/kg IV Early (p<.001) treatment groups. Treatment of dogs shortly after birth with IT+IV rhIDU (IT + IV Early) led to normal to near-normal GAG levels in the meninges and histologic absence of storage vacuoles. Lysosomal storage was reduced in spinal anterior horn cells in 1.57mg/kg IV Early and IT + IV Early animals. All dogs in IT + IV Adult and IV Adult groups had compression of their spinal cord at 12-15months of age determined by magnetic resonance imaging and was due to protrusion of spinal disks into the canal. Cord compression developed in 3 of 4 dogs in the 0.58mg/kg IV Early group; 2 of 3 dogs in the IT + IV Early group; and 0 of 4 dogs in the 1.57mg/kg IV Early group by 12-18months of age. IT + IV rhIDU was more effective than IV rhIDU alone for treatment of meningeal storage, and it prevented meningeal GAG accumulation when begun early. High-dose IV rhIDU from birth (1.57mg/kg weekly) appeared to prevent cord compression due to protrusion of spinal disks.

Cognitive and neuroradiological improvement in three patients with attenuated MPS I treated by laronidase

Stem cell transplantation is not appropriate first-line treatment for attenuated phenotypes of mucopolysaccharidosis type I (MPS I). In three patients with attenuated MPSA I treated by laronidase, Patients 2 and 3 displayed significant cognitive improvement within 2years; Patients 1 and 3 displayed improvement on MRI scans of the brain.

Efficacy of recombinant human alpha-L-iduronidase (laronidase) on restricted range of motion of upper extremities in mucopolysaccharidosis type I patients

The aims of the study were to assess the effectiveness of enzyme replacement therapy (ERT) with laronidase on the range of motion (ROM) of upper extremities and influence on activities of daily living (ADLs) of patients with mucopolysaccharidosis type I (MPS I). The ROM of 17 patients with MPS I was followed from the first year of life until the introduction of ERT and after 52-208 weeks of treatment. In all patients (group 1, n = 10), passive ROM was assessed. In patients with Hurler/Scheie or Scheie phenotype (group 2, n = 7) both passive and active ROM, as well as daily life activities, were evaluated. Passive and active ROM was measured by a goniometer, while a health assessment questionnaire was used to assess activities of daily living. The data since the first months of life until the beginning of treatment were obtained by retrospective review of patients' charts. Restriction in ROM of the upper extremities of patients with MPS I was observed from the first year of life. These limitations intensified and became more severe with the patients' age, making patients' self-care more difficult or even impossible. Introduction of ERT led to slower progression of symptoms, especially in the passive range of motion in all patients. Additionally, patients with normal mental development, or only slightly delayed (group 2), who underwent active physical rehabilitation (including mobilisation of nerve system, passive techniques for joint mobility, active gymnastics for muscle power, as well as massage and the training of families for therapy at home) showed improvement in active movement followed by enhanced self-care.

Anthropometric data of 14 patients with mucopolysaccharidosis I: retrospective analysis and efficacy of recombinant human alpha-L-iduronidase (laronidase)

OBJECTIVES

Our goal was to evaluate growth patterns in terms of body height, weight, head and chest circumference in patients with mucopolysaccharidosis type I (MPS I) without treatment and after enzyme replacement therapy (ERT) with alpha-l-iduronidase (laronidase).

PATIENTS AND METHODS

Anthropometric features of 14 patients with MPS I were followed from birth until the introduction of ERT (group 1-1st year of life, group 2 3rd year of life), after 52-260 weeks of ERT and periodically during treatment. The data since birth until beginning of treatment was obtained by retrospective review of patients' charts. Patients received intravenous laronidase at 100 U/kg (0.58 mg/kg) weekly for 52-260 weeks.

RESULTS

Patients from group 1 (n=7) and group 2 (n=7) had similar characteristics at the time of birth but showed significant difference when compared with healthy population. Growth patterns were associated significantly with the MPS I at birth. After 96-260 weeks of ERT, patients receiving laronidase (group 1) compared with group 2 did not show statistically significant improvement.

CONCLUSIONS

Anthropometric features of patients with MPS I significantly differ from the healthy population. Children with MPS I grew considerably slower, and differences between healthy and affected children increased with age. In studied patients with MPS I, laronidase did not appear to alter the growth patterns.

[The development of cognitive functions in children with Hurler phenotype mucopolysaccharidosis type I on enzyme replacement therapy with laronidase]

INTRODUCTION

Mucopolysaccharidosis type I (MPS I) Hurler syndrome, Hurler/Scheie i Scheie is a metabolic disorder manifesting in early childhood, and characterized by the accumulation of mucopolysaccharides (glycosaminoglycans - GAG) in the cells, blood, and connective tissues. Eventually, this causes damage to cells and organs, leading to progressive impairment of the child's physical abilities, organ function, and mental development. Treatment with enzyme replacement therapy (ERT) alleviates many symptoms of the disease, however, there is no evidence indicating that ERT is effective in the prevention of nervous system degradation.

THE AIM OF THE STUDY

The current study seeks to assess the development of cognitive functions in ERT-treated children with Hurler syndrome.

MATERIAL AND METHODS

The analysis covers 8 children suffering from MPS type I (7 boys and 1 girl), aged from 9.8 months to 12.7 months at the beginning of the study. All were on enzymatic treatment for the first year of life. The level of intellectual development was measured using the Psyche Cattell Infant's Intelligence Scale.

RESULTS

Children with MPS type I achieved significantly lower IQ scores compared to the reference group of healthy children. Qualitative analyses revealed that the acquisition of skills and new cognitive functions is very slow in children with MPS type I.

CONCLUSIONS

1. Among children with MPS type I, there was a measurable decrease in IQ associated with advancing age. 2. In spite of lower IQ, the acquisition of new abilities does occur, but the pace of that development is slower than that expected for the child's age. 3. The study reveals the need for functional diagnosis of development, in order to assess the progress made by the child.

Scheie syndrome: enzyme replacement therapy does not prevent progression of cervical myelopathy due to spinal cord compression

Hurler-Scheie syndrome is caused by alpha-l-iduronidase deficiency. Enzyme replacement therapy (ERT) can improve physical capacity and reduces organomegaly. However, the effect on bradytrophic connective tissue is limited. As intravenously administered enzyme cannot cross the blood-brain barrier, the therapy of choice for the more severe Hurler syndrome is haematopoietic stem cell transplantation (HCT). In the more attenuated Scheie syndrome, neurological impairment is less severe; therefore, ERT may be appropriate to treat these patients. Information on long-term outcome in Scheie patients undergoing ERT is scarce. We report a 38-year-old female Scheie patient who has been on ERT for 8 years. While non-neurological symptoms improved, she developed paresthesias in her hands and feet and progressive pain in her legs. Somatosensory evoked potentials were abnormal, suggesting dysfunction of the dorsal funiculus and lemniscus medialis. After 6 years of ERT, a spinal MRI showed dural thickening at the upper cervical spine. These soft-tissue deposits are presumably due to the accumulation of mucopolysaccharides. Intramedullary hyperintensities at the level of C1/2 revealed cervical myelopathy. An MRI before the start of ERT had shown milder spinal lesions. Cystic lesions in the white matter of the centrum semiovale due to dilated Virchow-Robin spaces were essentially unchanged compared with the MRI scan before ERT. Decompression of the spinal cord resulted in clinical improvement. In an adult patient with Scheie syndrome, ERT failed to prevent progression of cervical myelopathy. Clinical significance of cerebral changes is unclear. Whether early HCT or intrathecal ERT could have prevented these lesions remains speculative.

Postmortem studies on a patient with mucopolysaccharidosis type I: histopathological findings after one year of enzyme replacement therapy

Deficiency of lysosomal α-L-iduronidase results in systemic accumulation of glycosaminoglycans (GAGs). Cardiac lesions due to accumulation of GAGs include hypertrophic cardiomyopathy, valvular insufficiency/stenosis, and coronary artery stenosis due to intimal proliferation. Cardiac dysfunction is one of the most common causes of death in patients with mucopolysaccharidosis type I (MPS I). Enzyme replacement therapy (ERT) with laronidase has shown clear effects in reduction of hepatomegaly and it has been unclear whether ERT could improve or prevent the cardiac lesions. Postmortem findings in a 3 1/2-year-old boy diagnosed with MPS I at age 2 years are described. He received ERT with laronidase at 100 U/kg/week for one year. He suddenly developed cardiorespiratory failure and died the next day after C2-3 spinal surgery for instability. Postmortem examination showed hypertrophic cardiomyopathy, severe aortic valve and mitral valve thickening with shortened chordae, and endocardial fibroelastosis. Histology of the cardiac tissue revealed increased perivascular and interstitial connective tissue in the myocardium and intimal thickening causing stenosis in the cardiac vessels. Electron-microscopic (EM) studies of the thickened endocardium revealed numerous histiocytes with enlarged lysosomes. EM examination of the liver and the cardiac muscle revealed no accumulation of GAGs. ERT with laronidase showed clear effects in removing GAGs from the liver and the cardiac muscle. However, it did not show a clear effect on the thickened endocardium, myocardial perivascular and interstitial connective tissue or intimal thickening in the epicardial vessels.

Enzyme replacement therapy in 12 patients with MPS I-H/S with homozygous p.Leu490Pro mutation

We describe a cohort of 14 Hurler-Scheie patients homozygous for the p.Leu490Pro missense mutation in the alpha-L-iduronidase gene. Now based in the UK, they are all of Pakistani/Kashmiri descent; 64% were female; 11/14 (79%) had a sibling or cousin with MPS I and the parents are consanguineous in all cases. The median age at diagnosis was 1.8 years (range from antenatal diagnosis to 16.5 years). Twelve were on ERT with recombinant human alpha-L-iduronidase (IDUA; Laronidase, Genzyme) for a median duration of 22.5 months (range 2-71 months) and median age at commencement of ERT was 8.6 years (range 0.4-23.1 years). There was clear improvement in the size of liver and spleen as well as reduction in urine glycosaminoglycans (GAGs). The mean (range) urine GAG levels in mg/mmol creatinine were 63.4 (28.9-105.6), 28.3 (10.9-41.4), 22.8 (12.1-43.1), 15.7 (9.2-24.8) and 16.3 (10.1-21.0) at commencement, 3 months post ERT, 6 months post ERT, 12 months post ERT and 24 months post ERT, respectively. Effects on growth were not clear as there does not seem to be an obvious trend of increase or decrease in height after commencement of ERT and this seems to be the case regardless of the age at which ERT was started.

Successful treatment of severe heart failure in an infant with Hurler syndrome

Hurler syndrome (MPS IH) is the most severe form of mucopolysaccharidosis type I. It is caused by deficiency or absence of the enzyme alpha-L-iduronidase. Cardiac involvement includes cardiomyopathy and valve and coronary pathology. Cardiomyopathy causing symptoms in an infant with MPS IH carries a very poor prognosis. We describe a previously healthy 10-week-old boy who was admitted to hospital critically ill with severe heart failure. Echocardiography on admission showed severe dilatation of the left ventricle and moderate insufficiency of the left-sided cardiac valves. Accumulation of heparan sulfate and dermatan sulfate substrates in the urine and leukocyte analysis confirmed the diagnosis of MPS IH. Enzyme replacement therapy (ERT) with intravenous laronidase at a standard dosage of 100 U/kg weekly was started soon after. This improved the child's general clinical wellbeing dramatically. His cardiac function improved steadily over a period of months. Stem cell transplantation from cord blood is not available in Norway and he underwent successful transplantation from an unrelated bone marrow donor at the age of 11 months. ERT was stopped four months later. At the age of 26 months his heart function is close to normal and he is currently on no medication. This report highlights three important clinical issues: (1) MPS IH must be considered in infants with cardiomyopathy; (2) early ERT may have a significant impact on short-term outcome in children less than 18 months old with severe cardiomyopathy; (3) our report confirms that patients in poor condition benefit from ERT before stem cell transplantation.

Pre-stem cell transplantation enzyme replacement therapy in Hurler syndrome does not lead to significant antibody formation or delayed recovery of the endogenous enzyme post-transplant: a case report

Combined enzyme replacement therapy (ERT) and stem cell transplant (SCT) were done for a two year old boy with severe Hurler syndrome(HS) with the aim to decrease transplant related complications. He tolerated both the procedures well without any major complications. Urine glycosaminoglycans (GAGs) decreased post-transplant and child has improved clinically and neurologically. Insignificant titers of the anti-iduronidase antibodies which developed post-transplant did not affect the transplant outcome or the endogenous recovery of the alpha-L-iduronidase enzyme.

Enzyme replacement therapy in two patients with an advanced severe (Hurler) phenotype of mucopolysaccharidosis I

Although offered, two of our Hurler patients (OMIM 607014) had not undergone bone marrow transplantation at an early stage of their disease. Rapid disease progression had resulted in a range of signs and symptoms representative of advanced neurodegeneration and debilitating somatic Hurler disease. As general palliative care had only little impact on the burden of disease, laronidase (Aldurazyme) treatment was introduced in an attempt to alleviate somatic symptoms and to improve the quality of their lives. Therapeutic benefits from enzyme replacement therapy included improvements in general physical condition and mood, as well as normalisation of the sleep patterns, disappearance of sleep apnoea syndrome and reduction of hepatosplenomegaly. Improvements in the joint mobility were mainly limited to the wrists and hips. In addition, improvements in cardiac function, stool habits, visual acuity, corneal clouding and hearing were observed in one or both patients. Irreversible skeletal changes did not deteriorate. The neurological outcome of these patients is likely not influenced as laronidase is believed not to pass the blood-brain barrier. Therefore, the decision to initiate this therapy in transplant-naïve Hurler patients with an advanced stage of the disease should be taken after careful consideration.

CONCLUSION

We are of the opinion that the option of enzyme therapy should not be excluded in severely affected Hurler patients who cannot undergo bone marrow transplantation. Stabilization or amelioration of somatic disease and improvement of the quality of their lives should be embraced as therapeutic goals.

Intrathecal enzyme replacement therapy: successful treatment of brain disease via the cerebrospinal fluid

Treatment of brain disease with recombinant proteins is difficult due to the blood-brain barrier. As an alternative to direct injections into the brain, we studied whether application of high concentrations of therapeutic enzymes via intrathecal (IT) injections could successfully drive uptake across the ependyma to treat brain disease. We studied IT enzyme replacement therapy with recombinant human iduronidase (rhIDU) in canine mucopolysaccharidosis I (MPS I, Hurler syndrome), a lysosomal storage disorder with brain and meningeal involvement. Monthly or quarterly IT treatment regimens with rhIDU achieved supranormal iduronidase enzyme levels in the brain, spinal cord, and spinal meninges. All regimens normalized total brain glycosaminoglycan (GAG) storage and reduced spinal meningeal GAG storage by 58-70%. The improvement in GAG storage levels persisted three months after the final IT dose. The successful use of enzyme therapy via the CSF represents a potentially useful approach for lysosomal storage disorders.

[Overview of enzyme replacement therapy in mucopolysaccharidosis]

Mucopolysaccharidosis are rare, multisystemic and progressive diseases with an extremely various clinical spectrum. For the type I, II and VI mucopolysaccharidosis, enzyme replacement therapy is available. In these three diseases, enzyme replacement therapy induces a reduction in urinary glycosaminoglycanes excretion and on improvement in functional tests, 6 minutes walk test, pulmonary function test and range of motion.

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.

Outcome after three years of laronidase enzyme replacement therapy in a patient with Hurler syndrome

Enzyme replacement therapy (ERT) with laronidase, recombinant alpha-L-iduronidase, for mucopolysaccharidosis type I (MPS I) has been clinically available since April 2003. Pre-approval studies were performed on patients with the more attenuated forms of MPS I, Hurler-Scheie and Scheie syndromes. The clinical efficacy of laronidase on the severe form of MPS I, Hurler syndrome, is not well known. We present a patient with Hurler syndrome who has been treated with laronidase for 3 years. Clinically, the patient demonstrated improvement in urinary glycosaminoglycan (GAG) levels and hepatomegaly, but continued to experience decline in respiratory status, musculoskeletal and spinal involvement, and developmental skills. Overall, the benefit of ERT with laronidase in advanced Hurler syndrome appeared to be minimal in this patient.

A systematic review of the clinical effectiveness and cost-effectiveness of enzyme replacement therapies for Fabry's disease and mucopolysaccharidosis type 1

OBJECTIVES

To determine the clinical effectiveness and cost-effectiveness of the administration of intravenous enzyme replacement therapy (ERT) to symptomatic patients for the prevention of long-term damage and symptoms in Fabry's disease and in mucopolysaccharidosis type 1 (MPS1).

DATA SOURCES

Electronic databases from inception up to mid-2004. Contact with clinical experts.

REVIEW METHODS

Relevant studies were identified and assessed using recommended quality criteria.

RESULTS

The results suggested beneficial effects of ERT for Fabry's disease on measures of pain, cardiovascular function and some end-points reflecting neurosensory function. Renal function appeared to be stabilised by ERT. At present there are no utility-related health-related quality of life data on which to assess the relative health gain of ERT in MPS1. In order to be able to demonstrate the full extent of health gain from treatment, it was necessary to review the natural history of untreated patients in each disease in order to try to estimate the health loss prevented. The published information for Fabry's disease tallied with descriptions of a multi-system, life-threatening disorder particularly involving kidney, heart and brain with individual patients exhibiting many manifestations. The fragmentary information reviewed in 16 studies relevant to the natural history of MPS1 did not generate a coherent picture of disease progression and could provide little added value to published narrative reviews. For Fabry's disease, the mean cost per patient (50 kg) treated is around pounds sterling 85,000 per annum in England and Wales. The cost per patient varies considerably by dose. No published evidence reporting an economic evaluation of ERT for Fabry's disease was identified by this review. A dynamic decision model was constructed based on a birth cohort of male patients who are followed up until death. Owing to lack of information reported in the literature, many assumptions had to be applied. The key assumptions were that ERT returns patients to full health and a normal life expectancy. As far as possible, all assumptions favoured rather than detracted from the value of ERT. ERT was assumed to restore patients to full health in the base case. The estimated incremental cost-effectiveness ratio (ICER) in the base case was pounds sterling 252,000 per QALY (agalsidase beta). Univariate sensitivity analysis around the key assumptions produced ICERs ranging from pounds sterling 602,000 to pounds sterling 241,000. The base case unit cost of ERT was taken as pounds sterling 65.1/mg based on the cost of agalsidase beta. The unit cost would have had to be reduced to pounds sterling 9 to obtain an ICER of pounds sterling 30,000 per QALY. For MPS1, the mean cost per child patient (20 kg) treated is approximately pounds sterling 95,000 and an adult (70 kg) around pounds sterling 335,000 per annum in England and Wales. The cost per patient varies considerably by dose. There is no published evidence reporting an economic evaluation of ERT for MPS1 and no study was identified that reported the quality of life of MPS1 patients within a utility format. Furthermore, no or minimal information of the severity and rate of change of clinical manifestations of disease or the impact of ERT on these factors was identified. Information on the effect of ERT on mortality is also lacking owing to the relatively short time that the treatment has been available. Given this lack of data, it was not possible to develop a cost-effectiveness model of ERT treatment for MPS1 as the model would consist almost completely of assumptions based on no published evidence, leading to an incremental cost per QALY result that would be meaningless.

CONCLUSIONS

Although ERT for treating the 'average' patient with Fabry's disease exceeds the normal upper threshold for cost-effectiveness seen in NHS policy decisions by over sixfold, and the value for MPS1 is likely to be of a similar order of magnitude, clinicians and the manufacturers argue that, as the disease is classified as an orphan disease under European Union legislation, it has special status, and the NHS has no option but to provide ERT. More information is required before the generalisability of the findings can be determined. Although data from the UK have been used wherever possible, this was very thin indeed. Nonetheless, even large errors in assumptions made will not reduce the ICER to anywhere near the upper level of treatments usually considered cost-effective. In order to overcome limited evidence on the natural history of the disease and the clinical effectiveness of the intervention, the establishment of disease-specific data registries is suggested to facilitate the process of technology assessment and improving patient care. These registries should attempt to include all affected patients in the UK, and collect longitudinal patient level data on clinically relevant problems, interventions received and quality of life in a utility format.

Cardiac findings after enzyme replacement therapy for mucopolysaccharidosis type I

Mucopolysaccharidosis type I is a lethal autosomal recessive storage disease caused by a deficiency of lysosomal alpha-L-iduronidase and the consequent systemic accumulation of glycosaminoglycan. Cardiomyopathy and valvar insufficiency occur as glycosaminoglycan accumulates in the myocardium, expands the spongiosa of cardiac valves, and proliferates within the myointima of the epicardial coronary arteries. Congestive heart failure and death occur within the first decade of life in the most severe cases. Allogeneic hematopoietic stem cell transplantation, used in severe forms of the disease, markedly prolongs survival, alleviates ventricular hypertrophy, and preserves cardiac function, but cardiac valves continue to thicken and valvular insufficiency progresses. Enzyme replacement therapy with human recombinant alpha-L-iduronidase has been proposed as an alternativee therapy for patients with mucopolysaccharidosis type I in whom the risk/benefit ratio of hematopoietic stem cell transplantation seems unfavorable. The investigators report the cardiac findings in a small series of 5 children with mucopolysaccharidosis type I who received enzyme replacement therapy for as long as 7 years. No deaths occurred during treatment. Left ventricular hypertrophy, which was present before therapy, resolved in all cases, and myocardial function remained normal. In contrast, the mitral and aortic valves remained thickened and, in some instances, developed progressive thickening and regurgitation. In conclusion, long-term enzyme replacement therapy has some clear benefits for the myocardium, but the cardiac valves appear unresponsive, and the ultimate effect on the coronary vasculature is unknown.

Impact of 144 weeks of laronidase therapy on body functions, endurance and general well-being in a Hurler-Scheie patient

The quality of life of a Hurler-Scheie patient who experienced improvement in several organ functions and regained mobility after 144 weeks of laronidase enzyme replacement therapy is described.

Haematopoietic cell transplantation (HCT) in combination with enzyme replacement therapy (ERT) in patients with Hurler syndrome

Hurler syndrome (MPS 1H) is the severe form of mucopolysaccharidosis type 1 (MPS 1). Haematopoietic cell transplantation (HCT) is the treatment of choice, but carries a high incidence of graft failure and morbidity. The use of enzyme replacement therapy (ERT) might improve the clinical signs and symptoms before HCT, resulting in less transplantation-related complications. Moreover, clearance of glycosaminoglycans (GAG's) from the bone marrow might improve engraftment. Twenty-two patients with MPS 1H received one or more HCT procedures in combination with ERT. One patient with severe cardiomyopathy improved significantly after ERT. All children were in a relatively good clinical condition before HCT. Of patients 59, 82 and 86% were alive and engrafted after one, two and three HCT procedures, respectively. Two patients died after repetitive HCT. No serious ERT-infusion-related toxicity occurred. ERT with HCT was well tolerated. Neither a positive nor a negative effect on the number of patients who are alive and engrafted after receiving ERT before HCT as compared to a historic cohort was noted. However, patients in a poor clinical condition before HCT might benefit from ERT.