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

Modern Approaches to the Management of Children with Mucopolysaccharidosis Type I

This article presents modern data on epidemiology, etiology, and clinical manifestations of mucopolysaccharidosis (MPS) type I in children. MPS develops due to deficiency of particular lysosomal enzyme which determines the disease type. The article considers in details disease's pathogenesis and classification. Evidence-based approaches to diagnosis (differential diagnosis included) are covered, moreover, special attention is paid to pathogenetic, symptomatic, and surgical treatment of MPS.

Enzyme replacement combinational therapy: effective treatments for mucopolysaccharidoses

INTRODUCTION

Mucopolysaccharidoses (MPS), as a group of inherited lysosomal storage disorders (LSDs), are clinically heterogeneous and characterized by multi-systemic manifestations, such as skeletal abnormalities and neurological dysfunctions. The currently used enzyme replacement therapy (ERT) might be associated with several limitations including the low biodistribution of the enzymes into the main targets, immunological responses against foreign enzymes, and the high cost of the treatment procedure. Therefore, a suitable combination approach can be considered for the successful treatment of each type of MPS.

AREAS COVERED

In this review, we provide comprehensive insights into the ERT-based combination therapies of MPS by reviewing the published literature on PubMed and Scopus. We also discuss the recent advancements in the treatment of MPS and bring up the hopes and hurdles in the futuristic treatment strategies.

EXPERT OPINION

Given the complex pathophysiology of MPS and its involvement in different tissues, the ERT of MPS in combination with stem cell therapy or gene therapy is deemed to provide a personalized precision treatment modality with the highest therapeutic responses and minimal side effects. By the same token, new combinational approaches need to be evaluated by using drugs that target alternative and secondary pathological pathways.

A deletion of IDUA exon 10 in a family of Golden Retriever dogs with an attenuated form of mucopolysaccharidosis type I

Background

Mucopolysaccharidosis type I (MPS‐I) is a lysosomal storage disorder caused by a deficiency of the enzyme α‐l‐iduronidase, leading to accumulation of undegraded dermatan and heparan sulfates in the cells and secondary multiorgan dysfunction. In humans, depending upon the nature of the underlying mutation(s) in the IDUA gene, the condition presents with a spectrum of clinical severity.

Objectives

To characterize the clinical and biochemical phenotypes, and the genotype of a family of Golden Retriever dogs.

Animals

Two affected siblings and 11 related dogs.

Methods

Family study. Urine metabolic screening and leucocyte lysosomal enzyme activity assays were performed for biochemical characterization. Whole genome sequencing was used to identify the causal mutation.

Results

The clinical signs shown by the proband resemble the human attenuated form of the disease, with a dysmorphic appearance, musculoskeletal, ocular and cardiac defects, and survival to adulthood. Urinary metabolic studies identified high levels of dermatan sulfate, heparan sulfate, and heparin. Lysosomal enzyme activities demonstrated deficiency in α‐l‐iduronidase activity in leucocytes. Genome sequencing revealed a novel homozygous deletion of 287 bp resulting in full deletion of exon 10 of the IDUA gene (NC_006585.3(NM_001313883.1):c.1400‐76_1521+89del). Treatment with pentosan polyphosphate improved the clinical signs until euthanasia at 4.5 years.

Conclusion and Clinical Importance

Analysis of the genotype/phenotype correlation in this dog family suggests that dogs with MPS‐I could have a less severe phenotype than humans, even in the presence of severe mutations. Treatment with pentosan polyphosphate should be considered in dogs with MPS‐I.

Critical clinical situations in adult patients with Mucopolysaccharidoses (MPS)

Background

Mucopolysaccharidoses (MPS) are rare, inherited disorders associated with enzyme deficiencies that result in glycosaminoglycan (GAG) accumulation in multiple organ systems. Management of MPS is evolving as patients increasingly survive to adulthood and undergo multiple surgeries throughout their lives. As surgeries in these patients are considered to be high risk, this can result in a range of critical clinical situations in adult patients.

Results

We discuss strategies to prepare for and manage critical clinical situations in adult patients with MPS, including supporting the multidisciplinary team, preoperative and airway assessments, surgical preparations, and postoperative care. We also present eight critical clinical cases (age range: 21–38 years) from four leading inherited metabolic disease centres in Europe to highlight challenges and practical solutions to optimise the care of adult patients with MPS. Critical clinical situations included surgical procedures, pregnancy and a thrombus in a port-a-cath.

Conclusions

Individualised strategies to manage critical clinical situations need to be developed for each patient to compensate for the heterogeneous symptoms that may be present and the potential complications that may occur. These strategies should include input from the wider MDT, and be coordinated by metabolic specialists with expertise in the management of MPS disorders and surgery in adult patients with MPS.

Therapeutic Options for Mucopolysaccharidoses: Current and Emerging Treatments

Mucopolysaccharidoses (MPS) are inborn errors of metabolism produced by a deficiency of one of the enzymes involved in the degradation of glycosaminoglycans (GAGs). Although taken separately, each type is rare. As a group, MPS are relatively frequent, with an overall estimated incidence of around 1 in 20,000-25,000 births. Development of therapeutic options for MPS, including hematopoietic stem cell transplantation (HSCT) and enzyme replacement therapy (ERT), has modified the natural history of many MPS types. In spite of the improvement in some tissues and organs, significant challenges remain unsolved, including blood-brain barrier (BBB) penetration and treatment of lesions in avascular cartilage, heart valves, and corneas. Newer approaches, such as intrathecal ERT, ERT with fusion proteins to cross the BBB, gene therapy, substrate reduction therapy (SRT), chaperone therapy, and some combination of these strategies may provide better outcomes for MPS patients in the near future. As early diagnosis and early treatment are imperative to improve therapeutic efficacy, the inclusion of MPS in newborn screening programs should enhance the potential impact of treatment in reducing the morbidity associated with MPS diseases. In this review, we evaluate available treatments, including ERT and HSCT, and future treatments, such as gene therapy, SRT, and chaperone therapy, and describe the advantages and disadvantages. We also assess the current clinical endpoints and biomarkers used in clinical trials.

Mutation analysis and clinical characterization of Iranian patients with mucopolysaccharidosis type I

Background

Mucopolysaccharidosis type I (MPSI) is a rare autosomal recessive disorder caused by a deficiency of α‐l‐iduronidase (IDUA) encoded by the IDUA gene. We examined the mutation spectrum of the IDUA gene to explain the clinical, biochemical, and molecular features in 21 Iranian patients with MPSI.

Methods

Sanger sequencing was used to measure the IDUA gene sequence in the coding region and exon‐intron boundaries. We recorded the clinical findings of studied patients at the first diagnosis of disease and then during the treatment and follow‐up.

Results

Five different missense disease‐causing mutations were determined in our patient groups, indicating 90.48% of detection rate. The most widespread mutation was the p.Y109H, occurring in 15.625% of all alleles, which was reported for the first time in our study. Other frequent mutations were as follows: p.Ser157Pro (12.5%), p.Gly84Arg (12.5%), p.Asp257His (9.375%), and p.Asp301Glu (9.375%). Three ones of them were new missense mutations: p.Ser157Pro, p.Asp257His, and p.Asp301Glu.

Discussion

The results of this study explain the different spectrum of IDUA gene mutations in our patients with MPSI. We introduced here 32 different variants including four new variants: p.Y109H (15.625%), p.S157P (12.5%), p.D257H (9.375%), and p.D301E (9.375%). In this series, there was no relationship between the happening of clinical features and genotype variations and biochemical findings.

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.

Biochemical, machine learning and molecular approaches for the differential diagnosis of Mucopolysaccharidoses

This study was aimed to construct classification and regression tree (CART) model of glycosaminoglycans (GAGs) for the differential diagnosis of Mucopolysaccharidoses (MPS). Two-dimensional electrophoresis and liquid chromatography-tandem mass spectrometry (LC-MS/MS) were used for the qualitative and quantitative analysis of GAGs. Specific enzyme assays and targeted gene sequencing were performed to confirm the diagnosis. Machine learning tools were used to develop CART model based on GAG profile. Qualitative and quantitative CART models showed 96.3% and 98.3% accuracy, respectively, in the differential diagnosis of MPS. The thresholds of different GAGs diagnostic of specific MPS types were established. In 60 MPS positive cases, 46 different mutations were identified in six specific genes. Among 31 different mutations identified in IDUA, nine were nonsense mutations and two were gross deletions while the remaining were missense mutations. In IDS gene, four missense, two frameshift, and one deletion were identified. In NAGLU gene, c.1693C > T and c.1914_1914insT were the most common mutations. Two ARSB, one case each of SGSH and GALNS mutations were observed. LC-MS/MS-based GAG pattern showed higher accuracy in the differential diagnosis of MPS. The mutation spectrum of MPS, specifically in IDUA and IDS genes, is highly heterogeneous among the cases studied.

Bull's eye maculopathy and subfoveal deposition in two mucopolysaccharidosis type I patients on long-term enzyme replacement therapy

Purpose

To report retinal findings in two patients with mucopolysaccharidosis type I (MPS I) receiving human recombinant alpha-l-iduronidase (Laronidase) as enzyme replacement therapy.

Observations

Patient 1 had visual acuity 20/20 right eye, 20/25 left eye and unremarkable anterior segment and retinal examination. Optical coherence tomography (OCT) scanning demonstrated parafoveal thinning and subfoveal hyperreflectant material. Patient 2 had visual acuity 20/20 both eyes, with dense nuclear cataract both eyes. Retinal examination demonstrated bull's eye maculopathy both eyes. OCT scanning confirmed parafoveal atrophy and demonstrated similar appearing subfoveal hyperreflectant material, more prominent than in case 1.

Conclusions and importance

These two patients with MPS I receiving Laronidase treatment have developed bull's eye maculopathy changes and subfoveal deposition of hyperreflectant material despite excellent compliance and good tolerance of the standard dose of enzyme therapy for this disorder. Further studies are required to determine the nature of the material, the incidence and the effect of enzyme replacement therapy on these findings in patients with MPS I.

Genomic approaches to diagnose rare bone disorders

Skeletal dysplasias are Mendelian disorders with a prevalence of approximatively 1 in every 5000 individuals and can usually be diagnosed based on clinical and radiological findings. However, given that some diseases can be caused by several different genes, and that some genes can cause a variety of different phenotypes, achieving a molecular diagnosis can be challenging. We review here different approaches, from single gene sequencing to genomic approaches using next-generation sequencing, to reach a molecular diagnosis for skeletal dysplasias. We will further describe the overall advantages and limitations of first, second and third-generation sequencing, including single gene sequencing, whole-exome and genome sequencing (WES and WGS), multiple gene panel sequencing and single molecule sequencing. We also provide a brief overview of potential future applications of emerging technologies.

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.

Mucopolysaccharidosis type I, II and VI and response to enzyme replacement therapy: Results from a single-center case series study

Mucopolysaccharidoses (MPS) types I, II and VI are associated with deficiencies in alpha-L-iduronidase, iduronate-2-sulfatase and N-acetylgalactosamine-4-sulfatase, respectively, and generally involve progressive and multi-systemic clinical manifestations. Enzyme replacement therapy (ERT) appears to be reasonably well tolerated. The aim of this study was to examine clinical and diagnostic findings of a series of pediatric and adult MPS patients, and assess the safety and efficacy of ERT in children and adults with MPS type I, II and VI. Pediatric and adult patients were treated weekly with 1 mg/kg recombinant human N-acetylgalactosamine-4-sulphatase (rhASB), 0.45 mg/kg alpha-L-iduronidase, or 0.5 mg/kg iduronate-2-sulfatase. Clinical and biochemical parameters with ERT were evaluated for a mean duration of 5 years. Mantel-Haenszel risk ratios and associated 95% confidence intervals (CIs) were calculated for rates of death among different types of enzyme replacement therapies (ERTs). Twenty-seven patients (mean ages ‒ pediatric: 6.8 years; adult: 29 years) were included. ERT was found to be consistently well tolerated and effective in attenuating symptoms, but did not prevent the progression of the disease or reduce mortality rates. Our findings demonstrated that early diagnosis and initiation of ERT are critical for improvements in patient-important outcomes and quality of life, although disease progression and mortality rates remain high.

Open issues in Mucopolysaccharidosis type I-Hurler

Mucopolysaccharidosis I-Hurler (MPS I-H) is the most severe form of a metabolic genetic disease caused by mutations of IDUA gene encoding the lysosomal α-L-iduronidase enzyme. MPS I-H is a rare, life-threatening disease, evolving in multisystem morbidity including progressive neurological disease, upper airway obstruction, skeletal deformity and cardiomyopathy. Allogeneic hematopoietic stem cell transplantation (HSCT) is currently the gold standard for the treatment of MPS I-H in patients diagnosed and treated before 2–2.5 years of age, having a high rate of success. Beyond the child’s age, other factors influence the probability of treatment success, including the selection of patients, of graft source and the donor type employed. Enzyme replacement therapy (ERT) with human recombinant laronidase has also been demonstrated to be effective in ameliorating the clinical conditions of pre-transplant MPS I-H patients and in improving HSCT outcome, by peri-transplant co-administration. Nevertheless the long-term clinical outcome even after successful HSCT varies considerably, with a persisting residual disease burden. Other strategies must then be considered to improve the outcome of these patients: one is to pursue early pre-symptomatic diagnosis through newborn screening and another one is the identification of novel treatments. In this perspective, even though newborn screening can be envisaged as a future attractive perspective, presently the best path to be pursued embraces an improved awareness of signs and symptoms of the disorder by primary care providers and pediatricians, in order for the patients’ timely referral to a qualified reference center. Furthermore, sensitive new biochemical markers must be identified to better define the clinical severity of the disease at birth, to support clinical judgement during the follow-up and to compare the effects of the different therapies. A prolonged neuropsychological follow-up of post-transplant cognitive development of children and residual disease burden is needed. In this perspective, the reference center must guarantee a multidisciplinary follow-up with an expert team. Diagnostic and interventional protocols of reference centers should be standardized whenever possible to allow comparison of clinical data and evaluation of results. This review will focus on all these critical issues related to the management of MPS I-H.

Transcranial pulsed ultrasound facilitates brain uptake of laronidase in enzyme replacement therapy for Mucopolysaccharidosis type I disease

Background

Mucopolysaccharidosis type I (MPS I) is a debilitating hereditary disease characterized by alpha-L-iduronidase (IDUA) deficiency and consequent inability to degrade glycosaminoglycans. The pathological accumulation of glycosaminoglycans systemically results in severe mental retardation and multiple organ dysfunction. Enzyme replacement therapy with recombinant human alpha-L-iduronidase (rhIDU) improves the function of some organs but not neurological deficits owing to its exclusion from the brain by the blood-brain barrier (BBB).

Methods

We divided MPS I mice into control group, enzyme replacement group with rhIDU 2.9 mg/kg injection, enzyme replacement with one-spot ultrasound treatment group, and enzyme replacement with two-spot ultrasound treatment group, and compare treatment effectiveness between groups. All ultrasound treatments were applied on left side brain. Evans blue was used to simulate the distribution of rhIDU in the brain.

Results

Transcranial pulsed weakly focused ultrasound combined with microbubbles facilitates brain rhIDU delivery in MPS I mice receiving systemic enzyme replacement therapy. With intravenously injected rhIDU 2.9 mg/kg, the IDUA enzyme activity on the ultrasound treated side of the cerebral hemisphere raised to 7.81-fold that on the untreated side and to 75.84% of its normal value. Evans blue simulation showed the distribution of the delivered drug was extensive, involving a large volume of the treated cerebral hemisphere. Two-spot ultrasound treatment scheme is more efficient for brain rhIDU delivery than one-spot ultrasound treatment scheme.

Conclusions

Transcranial pulsed weakly focused ultrasound can open BBB extensively and facilitates brain rhIDU delivery. This novel technology may provide a new MPS I treatment strategy.

Immune tolerance induction for laronidase treatment in mucopolysaccharidosis I

Enzyme replacement therapy (ERT) can produce anti-drug antibody (ADA) responses that reduce efficacy or lead to hypersensitivity reactions. Six patients with severe mucopolysaccharidosis type I (MPS I/Hurler syndrome) who did not receive hematopoietic stem cell transplantation underwent an immunosuppression regimen prior to initiating ERT with laronidase. The primary endpoint for immune tolerance induction was the number of patients with an ADA titer ≤ 3200 after 24 weeks of laronidase at the labeled dose. Cyclosporine levels were measured weekly and doses adjusted to maintain trough levels above 400 mg/mL. A 6-week (Cohort 1) or 12-week (Cohort 2) immune tolerance induction period with cyclosporine (initial dose: 15 or 20 mg/kg/day), azathioprine (initial dose: 2.5 or 5 mg/kg/day) and low-dose laronidase infusions (0.058–0.29 mg/kg/week) was followed by an immune-challenge period with laronidase infusions at the labeled dose (0.58 mg/kg/week) for 24 weeks. Anti-laronidase IgG titers were determined following treatment. There were 147 treatment-emergent adverse events reported, most of which were mild and not related to the study treatment. While there was no evidence of immune tolerance in 3 of 3 patients in Cohort 1, there were some indications of immune tolerance induction in 2 of 3 patients in Cohort 2. Patients with lower ADA titers showed greater reductions in urinary glycosaminoglycan excretion. Routine monitoring of plasma cyclosporine parent-compound levels by high pressure liquid chromatography proved difficult for clinical practice. The evolving clinical management of MPS I and a better understanding of the clinical impact of laronidase-related immunogenicity require reassessment of immune modulation strategies in patients with MPS I receiving laronidase treatment. Clinical Trial Registration: NCT00741338.