Capturing phenotypic heterogeneity in MPS I: results of an international consensus procedure

<p>Abstract</p> <p>Background</p> <p>Mucopolysaccharidosis type I (MPS I) is traditionally divided into three phenotypes: the severe Hurler (MPS I-H) phenotype, the intermediate Hurler-Scheie (MPS I-H/S) phenotype and the attenuated Scheie (MPS I-S) phenotype. However, there are no clear criteria for delineating the different phenotypes. Because decisions about optimal treatment (enzyme replacement therapy or hematopoietic stem cell transplantation) need to be made quickly and depend on the presumed phenotype, an assessment of phenotypic severity should be performed soon after diagnosis. Therefore, a numerical severity scale for classifying different MPS I phenotypes at diagnosis based on clinical signs and symptoms was developed.</p> <p>Methods</p> <p>A consensus procedure based on a combined modified Delphi method and a nominal group technique was undertaken. It consisted of two written rounds and a face-to-face meeting. Sixteen MPS I experts participated in the process. The main goal was to identify the most important indicators of phenotypic severity and include these in a numerical severity scale. The correlation between the median subjective expert MPS I rating and the scores derived from this severity scale was used as an indicator of validity.</p> <p>Results</p> <p>Full consensus was reached on six key clinical items for assessing severity: age of onset of signs and symptoms, developmental delay, joint stiffness/arthropathy/contractures, kyphosis, cardiomyopathy and large head/frontal bossing. Due to the remarkably large variability in the expert MPS I assessments, however, a reliable numerical scale could not be constructed. Because of this variability, such a scale would always result in patients whose calculated severity score differed unacceptably from the median expert severity score, which was considered to be the 'gold standard'.</p> <p>Conclusions</p> <p>Although consensus was reached on the six key items for assessing phenotypic severity in MPS I, expert opinion on phenotypic severity at diagnosis proved to be highly variable. This subjectivity emphasizes the need for validated biomarkers and improved genotype-phenotype correlations that can be incorporated into phenotypic severity assessments at diagnosis.</p

Rapid progression and mortality of lysosomal acid lipase deficiency presenting in infants

PurposeThe purpose of this study was to enhance understanding of lysosomal acid lipase deficiency (LALD) in infancy.MethodsInvestigators reviewed medical records of infants with LALD and summarized data for the overall population and for patients with and without early growth failure (GF). Kaplan-Meier survival analyses were conducted for the overall population and for treated and untreated patients.ResultsRecords for 35 patients, 26 with early GF, were analyzed. Prominent symptom manifestations included vomiting, diarrhea, and steatorrhea. Median age at death was 3.7 months; estimated probability of survival past age 12 months was 0.114 (95% confidence interval (CI): 0.009-0.220). Among patients with early GF, median age at death was 3.5 months; estimated probability of survival past age 12 months was 0.038 (95% CI: 0.000-0.112). Treated patients (hematopoietic stem cell transplant (HSCT), n = 9; HSCT and liver transplant, n = 1) in the overall population and the early GF subset survived longer than untreated patients, but survival was still poor (median age at death, 8.6 months).ConclusionsThese data confirm and expand earlier insights on the progression and course of LALD presenting in infancy. Despite variations in the nature, onset, and severity of clinical manifestations, and treatment attempts, clinical outcome was poor.Genet Med 18 5, 452-458

Impact of long-term elosulfase alfa on activities of daily living in patients with Morquio a syndrome in an open-label, multi-center, phase 3 extension study

BACKGROUND : Long-term safety and efficacy of elosulfase alfa enzyme replacement therapy (ERT) were assessed in 173 patients with Morquio A syndrome (mucopolysaccharidosis IVA) in a 96-week, open-label, multi-center, phase 3 extension study (MOR-005) of the pivotal 24-week, placebo-controlled study (MOR-004). Changes in efficacy endpoints were evaluated over 120 weeks, from MOR-004 baseline to MOR-005 week 96. We report the impact of ERT on activities of daily living (ADL) across three domains (mobility, self-care, and caregiver-assistance), as assessed by the Mucopolysaccharidosis Health Assessment Questionnaire (MPS-HAQ) after 72 and 120 weeks or approximately 1 and 2 years. RESULTS : Mean baseline MPS-HAQ domain scores showed impairments in mobility, self-care, and independence. The MOR-005 intent-to-treat population (ITT; N =169, including 158 with 2 years follow-up) showed sustained significant reductions (representing improvements) in mobility and self-care domain least square (LS) mean scores vs. baseline at 1 and 2 years and a non-significant decrease in the caregiver-assistance domain at 2 years. At week 120, LS mean (SE) changes from baseline were−0.5 (0.1) for mobility (P =0.002),−0.4 (0.1) for selfcare (P =0.001), and −1.0 (0.5) for caregiver-assistance (P= 0.06) (ITT population). Improvements in MPSHAQ domain scores vs. baseline at 1 and 2 years were greater in patients continuously treated with the weekly dosing regimen than in the total MOR-005 population and statistically significant across domains. A comparable untreated cohort of patients from the Morquio A Clinical Assessment Program (MorCAP) natural history study (ITT population, N =94, including 37 with 2 years follow-up) showed no improvement over 2 years, with two of the three domains worsening (LS mean (SE) changes from baseline: 0.3 (0.3) for mobility, 0.4 (0.2) for self-care, −0.5 (0.8) for caregiver-assistance). Changes in LS mean scores vs. baseline were statistically significantly different between MOR-005 and MorCAP for the mobility domain (−0.7 (SE 0.4), P=0.0490) and the self-care domain (−0.7 (SE 0.3), P=0.0146) at 2 years.Supplementary file 1. Items in the MPS Health Assessment Questionnaire (MPS-HAQ).Supplementary file 2. Items in the MPS Health Assessment Questionnaire (MPS-HAQ) (A) showing impairment in the self-care and mobility domains (score ≥ 1) and the caregiver-assistance domain (score > 1) in ≥ 70% of patients and (B) scored “unable to complete” or “complete assistance required” in ≥ 15% of patients in the MOR-005 ITT population.Supplementary file 3. Baseline demographics of patients from the MOR-005 intent-to-treat (ITT) and modified per-protocol (MPP) population and comparable patients from the MorCAP natural history study included in the 2-year analysis.This study and support in the process of manuscript development were funded by BioMarin Pharmaceutical Inc. The site in Monza (Dr. Parini) received continuous economical support for the clinical work of the Center from Fondazione Pierfranco and Luisa Mariani. Dr. Mitchell receives research support from Dr. Eleanor Mackenzie Harpur Pediatric Endowment Fund. This publication was supported in part (Dr. Harmatz) by the National Center for Advancing Translational Sciences, National Institutes of Health (NIH), through UCSF-CTSI Grant Number UL1 TR000004.http://www.elsevier.com/locate/ymgmeam2018Paediatrics and Child Healt

Multi-domain impact of elosufase alfa in Morquio A syndrome in the pivotal phase III trial

Objective: To report and discuss the multi-domain impact of elosulfase alfa, with focus on tertiary and composite endpoints, in the 24-week, randomized, double-blind, placebo-controlled phase 3 trial in patients with Morquio A syndrome (mucopolysaccharidosis IVA). Methods: Patients with Morquio A syndrome >= 5 aged years were randomized 1:1:1 to elosulfase alfa 2.0 mg/kg/week (qw; N = 58), elosulfase alfa 2.0 mg/kg/every other week (qow; N = 59), or placebo (N = 59) for 24 weeks. Primary and secondary efficacy measures were 6-minute walk test (6MWT; primary), 3-minute stair climb test (3-MSCT) and urinary keratan sulfate (KS). Safety was also evaluated. Tertiary efficacy measures included respiratory function measures, activities of daily living (MPS Health Assessment Questionnaire [MPS-HAQ]), anthropometric, echocardiographic and radiographic measures, hearing and corneal clouding assessment. In order to fully characterize treatment impact in this heterogeneous disorder, the effect of elosulfase alfa on composite efficacy measures was evaluated as well. Results: The study was not designed to have sufficient power for any of the tertiary outcomes. For most tertiary endpoints, subjects treated with the weekly dose of elosulfase alfa improved more than those receiving placebo. The largest treatment effects were seen in maximal voluntary ventilation (MVV), MPS-HAQ height, and growth rate. The qow group appeared similar to placebo. The analysis of a pre-specified composite endpoint (combining changes from baseline in 6MWT, 3MSCT and MW z-scores equally weighted) showed a modest positive impact of elosulfase alfa qw versus placebo group (P = 0.053). As a pre-specified supportive analysis, the O'Brien Rank Sum composite endpoint (changes from baseline in 6MWT, 3MSC, and MW), analysis also showed that the qw group performed better than the placebo group (P = 0.011). In post-hoc analyses, combinations of other endpoints were also explored using the O'Brien Rank Sum test and showed statistically significant differences between elosulfase alfa qw and placebo favoring elosulfase alfa qw. Differences between elosulfase alfa qow and placebo were not statistically significant. Positive changes were observed in most tertiary variables, demonstrating the efficacy of weekly treatment with elosulfase alfa. Conclusions: Treatment with weekly elosulfase alfa led to improvements across most efficacy measures, resulting in clinically meaningful benefits in a heterogeneous study population. (C) 2014 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/

Impact of long-term elosulfase alfa treatment on respiratory function in patients with Morquio A syndrome.

ObjectiveTo present long-term respiratory function outcomes from an open-label, multi-center, phase 3 extension study (MOR-005) of elosulfase alfa enzyme replacement therapy (ERT) in patients with Morquio A syndrome.MethodsIn part 1 of MOR-005, patients initially randomized to ERT in the 24-week pivotal study (MOR-004) remained on their regimen (2.0&nbsp;mg/kg/week or every other week); placebo patients were re-randomized to one of the two regimens. During part 2, all patients received elosulfase alfa 2.0&nbsp;mg/kg/week. Respiratory function was one of the efficacy endpoints evaluated in MOR-005. Change from MOR-004 baseline to 120&nbsp;weeks of treatment for the combined population was determined and compared with results from untreated patients from a Morquio A natural history study (MorCAP).ResultsMaximum voluntary ventilation (MVV) improved up to week 72 and then stabilized; forced vital capacity (FVC) and forced expiratory volume in 1&nbsp;s (FEV1) increased continuously over 120&nbsp;weeks. Mean increases in the modified per-protocol population was 9.2&nbsp;% for FVC, 8.8&nbsp;% for FEV1, and 6.1&nbsp;% for MVV after 120&nbsp;weeks. All patients ≤14&nbsp;years showed respiratory improvements, presumably in part related to growth; however, these were greater in treated patients. For those &gt;14&nbsp;years, treated patients showed improvements, while deterioration occurred in untreated. Altogether, the improvements were significantly greater (P &lt; 0.05) in treated patients.ConclusionsLong-term ERT is associated with sustained improvements in respiratory function in Morquio A. In younger patients (≤14&nbsp;years), some improvement may be ascribed to growth. In older patients, other mechanisms, e.g., decreased glycosaminoglycan storage, are likely involved

Attention and corpus callosum volumes in individuals with mucopolysaccharidosis type I.

ObjectivePrevious research suggests attention and white matter (WM) abnormalities in individuals with mucopolysaccharidosis type I (MPS I); this cross-sectional comparison is one of the first to examine the relationship of WM structural abnormalities as measured by corpus callosum (CC) volumes with attention scores to evaluate this relationship in a larger sample of patients with MPS I.MethodsVolumetric MRI data and performance on a computerized measure of sustained attention were compared for 18 participants with the severe form of MPS I (MPS IH), 18 participants with the attenuated form of MPS I (MPS IATT), and 60 typically developing age-matched controls.ResultsThe MPS I groups showed below-average mean attention scores (p &lt; 0.001) and smaller CC volumes (p &lt; 0.001) than controls. No significant associations were found between attention performance and CC volume for controls. Attention was associated with posterior CC volumes in the participants with MPS IH (p = 0.053) and total (p = 0.007) and anterior (p &lt; 0.001) CC volumes in participants with MPS IATT.ConclusionsWe found that attention and CC volumes were reduced in participants with MPS I compared to typically developing controls. Smaller CC volumes in participants with MPS I were associated with decreased attention; such an association was not seen in controls. While hematopoietic cell transplantation used to treat MPS IH may compound these effects, attention difficulties were also seen in the MPS IATT group, suggesting that disease effects contribute substantially to the clinical attentional difficulties seen in this population

Algorithm for the early diagnosis and treatment of patients with cross reactive immunologic material-negative classic infantile pompe disease: a step towards improving the efficacy of ERT.

OBJECTIVE: Although enzyme replacement therapy (ERT) is a highly effective therapy, CRIM-negative (CN) infantile Pompe disease (IPD) patients typically mount a strong immune response which abrogates the efficacy of ERT, resulting in clinical decline and death. This study was designed to demonstrate that immune tolerance induction (ITI) prevents or diminishes the development of antibody titers, resulting in a better clinical outcome compared to CN IPD patients treated with ERT monotherapy. METHODS: We evaluated the safety, efficacy and feasibility of a clinical algorithm designed to accurately identify CN IPD patients and minimize delays between CRIM status determination and initiation of an ITI regimen (combination of rituximab, methotrexate and IVIG) concurrent with ERT. Clinical and laboratory data including measures of efficacy analysis for response to ERT were analyzed and compared to CN IPD patients treated with ERT monotherapy. RESULTS: Seven CN IPD patients were identified and started on the ITI regimen concurrent with ERT. Median time from diagnosis of CN status to commencement of ERT and ITI was 0.5 months (range: 0.1-1.6 months). At baseline, all patients had significant cardiomyopathy and all but one required respiratory support. The ITI regimen was safely tolerated in all seven cases. Four patients never seroconverted and remained antibody-free. One patient died from respiratory failure. Two patients required another course of the ITI regimen. In addition to their clinical improvement, the antibody titers observed in these patients were much lower than those seen in ERT monotherapy treated CN patients. CONCLUSIONS: The ITI regimen appears safe and efficacious and holds promise in altering the natural history of CN IPD by increasing ERT efficacy. An algorithm such as this substantiates the benefits of accelerated diagnosis and management of CN IPD patients, thus, further supporting the importance of early identification and treatment initiation with newborn screening for IPD

Algorithm for the early diagnosis and treatment of patients with cross reactive immunologic material-negative classic infantile pompe disease: a step towards improving the efficacy of ERT.

ObjectiveAlthough enzyme replacement therapy (ERT) is a highly effective therapy, CRIM-negative (CN) infantile Pompe disease (IPD) patients typically mount a strong immune response which abrogates the efficacy of ERT, resulting in clinical decline and death. This study was designed to demonstrate that immune tolerance induction (ITI) prevents or diminishes the development of antibody titers, resulting in a better clinical outcome compared to CN IPD patients treated with ERT monotherapy.MethodsWe evaluated the safety, efficacy and feasibility of a clinical algorithm designed to accurately identify CN IPD patients and minimize delays between CRIM status determination and initiation of an ITI regimen (combination of rituximab, methotrexate and IVIG) concurrent with ERT. Clinical and laboratory data including measures of efficacy analysis for response to ERT were analyzed and compared to CN IPD patients treated with ERT monotherapy.ResultsSeven CN IPD patients were identified and started on the ITI regimen concurrent with ERT. Median time from diagnosis of CN status to commencement of ERT and ITI was 0.5 months (range: 0.1-1.6 months). At baseline, all patients had significant cardiomyopathy and all but one required respiratory support. The ITI regimen was safely tolerated in all seven cases. Four patients never seroconverted and remained antibody-free. One patient died from respiratory failure. Two patients required another course of the ITI regimen. In addition to their clinical improvement, the antibody titers observed in these patients were much lower than those seen in ERT monotherapy treated CN patients.ConclusionsThe ITI regimen appears safe and efficacious and holds promise in altering the natural history of CN IPD by increasing ERT efficacy. An algorithm such as this substantiates the benefits of accelerated diagnosis and management of CN IPD patients, thus, further supporting the importance of early identification and treatment initiation with newborn screening for IPD

PMPCA mutations cause abnormal mitochondrial protein processing in patients with non-progressive cerebellar ataxia

Non-progressive cerebellar ataxias are a rare group of disorders that comprise approximately 10% of static infantile encephalopathies. We report the identification of mutations in PMPCA in 17 patients from four families affected with cerebellar ataxia, including the large Lebanese family previously described with autosomal recessive cerebellar ataxia and short stature of Norman type and localized to chromosome 9q34 (OMIM #213200). All patients present with non-progressive cerebellar ataxia, and the majority have intellectual disability of variable severity. PMPCA encodes α-MPP, the alpha subunit of mitochondrial processing peptidase, the primary enzyme responsible for the maturation of the vast majority of nuclear-encoded mitochondrial proteins, which is necessary for life at the cellular level. Analysis of lymphoblastoid cells and fibroblasts from patients homozygous for the PMPCA p.Ala377Thr mutation and carriers demonstrate that the mutation impacts both the level of the alpha subunit encoded by PMPCA and the function of mitochondrial processing peptidase. In particular, this mutation impacts the maturation process of frataxin, the protein which is depleted in Friedreich ataxia. This study represents the first time that defects in PMPCA and mitochondrial processing peptidase have been described in association with a disease phenotype in humans