Eight-year clinical outcomes of long-term enzyme replacement therapy for 884 children with Gaucher disease type 1

Long-Term Outcomes of Disease Modifying Therapies in Gaucher Disease

OBJECTIVES

To study clinical response to treatment with enzyme replacement therapy (ERT) and substrate reduction therapy (SRT) in a cohort of Gaucher disease.

METHODS

Retrospective data of 8 patients of Gaucher disease was compiled. The treatment included all three currently available enzyme replacement therapies as well as substrate reduction therapy with Eliglustat. The relevant blood investigations were done in follow-up visits. The assessment of the effects of long-term treatment over varying periods up to 13 y was done with various issues related to the course of therapy documented.

RESULTS

Improvement in hematological parameters was seen in all patients. Reduction of spleen size occurred in 7 of 8 patients (87.5%). One patient had 2 successful pregnancies while on therapy. A distinct patient with type 3 Gaucher disease developed complication in the form of Gaucheroma within the spleen.

CONCLUSIONS

Awareness about the disease and the efficacy of the therapies amongst pediatricians will help in early diagnosis and better outcomes. The available therapies have changed the outcome of the patients and improved the quality of life in patients with Gaucher disease. The data of Indian patients is important at this juncture when under Rare Disease Policy, government funding has become available for ERT for Gaucher disease patients in India.

Pediatric Gaucher Disease Presenting with Massive Splenomegaly and Hepatic Gaucheroma

Gaucher Disease (GD) is a condition resulting from an autosomal recessive inheritance pattern, characterized by a deficiency of the lysosomal enzyme beta-glucocerebrosidase. This leads to the accumulation of glucocerebroside and other glycolipids in multiple tissues, causing damage to various organ systems. The diagnosis of GD can be challenging due to its heterogeneity, non-specific symptoms, and variability across different geographic regions and age groups. Although GD is suspected based on symptoms or signs, the diagnosis is confirmed through the measurement of deficient b-glucocerebrosidase activity and the identification of biallelic pathogenic variants in the GBA gene. Intravenous enzyme replacement therapy (ERT) is recommended for GD patients. In this paper, we report a case of a 2-year and 8-month-old girl with massive splenomegaly and radiological finding of hepatic gaucheroma, in whom a genetic study showed homozygous mutation on the GBA gene at c.1448T>C (p.Leu483Pro) and certified the diagnosis of GD. This patient represents the youngest child reported to have gaucheroma and also the first one presenting with gaucheroma at the diagnosis and not during the follow up, highlighting that GD should be routinely included in the differential diagnosis of children presenting with splenomegaly and hepatomegaly, taking into account that the early start of ERT can change the natural history of the disease-preventing serious complications.

Preclinical studies in Krabbe disease: A model for the investigation of novel combination therapies for lysosomal storage diseases

Krabbe disease (KD) is a lysosomal storage disease (LSD) caused by mutations in the galc gene. There are over 50 monogenetic LSDs, which largely impede the normal development of children and often lead to premature death. At present, there are no cures for LSDs and the available treatments are generally insufficient, short acting, and not without co-morbidities or long-term side effects. The last 30 years have seen significant advances in our understanding of LSD pathology as well as treatment options. Two gene therapy-based clinical trials, NCT04693598 and NCT04771416, for KD were recently started based on those advances. This review will discuss how our knowledge of KD got to where it is today, focusing on preclinical investigations, and how what was discovered may prove beneficial for the treatment of other LSDs.

Rare lysosomal disease registries: lessons learned over three decades of real-world evidence

Lysosomal storage disorders (LSD) are rare diseases, caused by inherited deficiencies of lysosomal enzymes/transporters, that affect 1 in 7000 to 1 in 8000 newborns. Individuals with LSDs face long diagnostic journeys during which debilitating and life-threatening events can occur. Clinical trials and classical descriptions of LSDs typically focus on common manifestations, which are not representative of the vast phenotypic heterogeneity encountered in real-world experience. Additionally, recognizing that there was a limited understanding of the natural history, disease progression, and real-world clinical outcomes of rare LSDs, a collaborative partnership was pioneered 30 years ago to address these gaps. The Rare Disease Registries (RDR) (for Gaucher, Fabry, Mucopolysaccharidosis type I, and Pompe), represent the largest observational database for these LSDs. Over the past thirty years, data from the RDRs have helped to inform scientific understanding and the development of comprehensive monitoring and treatment guidelines by creating a framework for data collection and establishing a standard of care, with an overarching goal to improve the quality of life of affected patients. Here, we highlight the history, process, and impact of the RDRs, and discuss the lessons learned and future directions.

The diagnosis and management of Gaucher disease in pediatric patients: Where do we go from here?

Gaucher disease (GD) is an autosomal recessive inherited lysosomal storage disease that often presents in early childhood and is associated with damage to multiple organ systems. Many challenges associated with GD diagnosis and management arise from the considerable heterogeneity of disease presentations and natural history. Phenotypic classification has traditionally been based on the absence (in type 1 GD) or presence (in types 2 and 3 GD) of neurological involvement of varying severity. However, patient management and prediction of prognosis may be best served by a dynamic, evolving definition of individual phenotype rather than by a rigid system of classification. Patients may experience considerable delays in diagnosis, which can potentially be reduced by effective screening programs; however, program implementation can involve ethical and practical challenges. Variation in the clinical course of GD and an uncertain prognosis also complicate decisions concerning treatment initiation, with differing stakeholder perspectives around efficacy and acceptable cost/benefit ratio. We review the challenges faced by physicians in the diagnosis and management of GD in pediatric patients. We also consider future directions and goals, including acceleration of accurate diagnosis, improvements in the understanding of disease heterogeneity (natural history, response to treatment, and prognosis), the need for new treatments to address unmet needs for all forms of GD, and refinement of the tools for monitoring disease progression and treatment efficacy, such as specific biomarkers.

Use of Identical INN "Imiglucerase" for Different Drug Products: Impact Analysis of Adverse Events in a Proprietary Global Safety Database

INTRODUCTION

Approved in 1994 and assigned the International Nonproprietary Name (INN) imiglucerase by the World Health Organization, Cerezyme® (Sanofi Genzyme) is an enzyme replacement therapy used to treat Gaucher disease in > 90 countries. At least two therapies approved outside the USA and the European Union, Abcertin® and Asbroder®, have adopted the identical INN imiglucerase. Both drugs were approved via regulatory pathways not aligned with World Health Organization Similar Biotherapeutic Product guidelines.

OBJECTIVE

We analyzed whether the use of the identical INN "imiglucerase" for these drugs impacts adverse event (AE) reporting in the Sanofi Global Safety Database.

METHODS

First, we reviewed all imiglucerase individual case safety reports (referred to as cases) including AE data reported between January 2012 and March 2018 that contained Abcertin or Asbroder in the narrative. In a second analysis, we examined cases from Mexico reported between May 2013 and March 2018 to assess changes in imiglucerase reporting following the 2015 approval of Asbroder in Mexico.

RESULTS

Fifty-six cases mentioning Asbroder and none mentioning Abcertin were retrieved in the first analysis. Upon close review, the AEs of 45 cases (80.4%) were attributed to Asbroder, one (1.8%) to Cerezyme; the specific drug attribution for the AEs of ten cases (17.9%) could not be determined. In the second analysis, a substantial increase in cases and AEs was observed in the period after Asbroder approval (73 cases with 150 AEs pre-approval vs 132 cases with 333 AEs post-approval). Twenty-three of 132 (17.4%) post-approval cases reported discontinuation of treatment (19 related to Asbroder AEs, and four related to Cerezyme AEs). Infusion-associated reactions occurred in 25/132 cases (17 Asbroder related, six Cerezyme related, two indeterminate).

CONCLUSIONS

This analysis demonstrates two potential consequences of identical INN use between Cerezyme and Asbroder: (1) an aggregate safety profile for Cerezyme that includes other products using the identical INN leading to inaccurate pharmacovigilance data and (2) healthcare providers switching, substituting, or potentially assuming interchangeability between the products. Identical INN use without the brand name differentiator may compromise pharmacovigilance data, potentially masking differences in safety profiles between products.

Clinical-genetic characteristics and treatment outcomes of Turkish children with Gaucher disease type 1 and type 3: A sixteen year single-center experience

Data from 38 children were retrospectively analyzed to determine the patient characteristics of Turkish children with Gaucher disease (GD) and evaluate the impact of enzyme replacement therapy (ERT) in a pediatric cohort consisting of two different sub-types of the disease, Gaucher disease type 1 (GD1) and type 3 (GD3). Both types were represented equally (GD1/GD3 = 20/18). L444P (35.5%) was the most common mutant allele while L444P/L444P (34.2%) was the most common genotype overall. Compound heterozygosity of N370S and L444P homozygosity were the dominant genotypes in Turkish children with GD1 and GD3, respectively. None of the patients had moderate to severe thrombocytopenia at last follow-up while the percent of patients with anemia decreased from 60% to 5.7% (p < 0.001). Significant improvements in mean liver (from 2.2 to 1.6 MN, p < 0.001) and spleen (from 15.5 to 7.6 MN, p < 0.001) volumes were observed in the first year of ERT. Linear growth was ameliorated as shown by the decrease in the percent of patients having short stature from 34.3% to 13.3% (p < 0.01) at year 5. Erlenmeyer flask deformity, osteopenia and scoliosis were common skeletal findings. Although none of the patients had lung disease at diagnosis, 20% developed radiological findings suggestive of pulmonary involvement. This single center experience is the first comprehensive study from Turkey not only reporting clinical and genetic characteristics of GD patients but also providing information on the outcomes of ERT in two different sub-types of GD. Genotypic background of Turkish children with GD is similar to western populations. Although visceral and hematological therapeutic goals are reached as early as one year of ERT in both sub-types, achieving normal growth takes several more years than suggested in significant number of children with GD.

Gaucher disease type 1 patients from the ICGG Gaucher Registry sustain initial clinical improvements during twenty years of imiglucerase treatment

BACKGROUND

Alglucerase enzyme replacement therapy was approved for Gaucher disease (GD) in the United States in 1991; imiglucerase in 1994. We report hematologic, visceral, bone pain, bone crisis, height, weight, and Body Mass Index (BMI) outcomes in patients treated for 20 (±3) years with subset analyses based on pre-treatment severity, genotype, and age at treatment initiation.

METHODS

GD type 1 (GD1) patients in the ICGG Gaucher Registry with complete sets of baseline, 10-year, and 20-year data are included (N = 475). Ten-year and 20-year data are compared to pre-treatment baseline, stratified by splenectomy status.

RESULTS

Non-splenectomized patients: Improvements observed at 10 years were maintained at 20 years for most outcomes. Mean changes from baseline at 10 and 20 years, respectively, were: spleen volume: 18.2 multiples of normal (MN) to 5.1 MN and 4.2 MN; liver volume: 1.8 MN to 1.0 MN and 1.0 MN; hemoglobin: 11.4 g/dL to 13.7 g/dL and 13.8 g/dL; platelet count: 91.6 × 10⁹/L to 168.0 × 10⁹/L and 169.1 × 10⁹/L; without bone crisis: 85.0% to 98.2% and 96.5%; without bone pain: 52.5% to 72.0% at 10 years, no significant change at 20 years (58.5%). Splenectomized patients: significant changes were observed in liver volume: 2.3 MN to 1.1 MN and 1.0 MN; hemoglobin: 11.7 g/dL to 13.3 g/dL and 13.4 g/dL; platelet count: 229.1 × 10⁹/L to 288.1 × 10⁹/L and 257.0 × 10⁹/L; without bone crisis: 52.2% to 91.3% and 100%; without bone pain: 16.3% to 30.6% (not significant) and 46.9%. Similar results were found in each of the subset analyses. Patients who start treatment during childhood have normal weight and height in young adulthood. Many treated adult patients are overweight or obese; however, this is consistent with BMI trends observed in the general population. After 1-2 years, the average biweekly imiglucerase dose is ~40 units/kg body weight.

CONCLUSION

Imiglucerase is an effective, long-term treatment for GD1. In a long-term observational setting, improvements seen during early treatment years are sustained by continuing treatment for 20 years, except for bone pain in non-splenectomized patients. These results are consistent when analyzed by different patient subsets, including by disease severity.

Successful treatment of Gaucher disease type 1 by enzyme replacement therapy over a 10-year duration in a Japanese pediatric patient: A case report

The prevalence of Gaucher disease (GD) in Japan is much lower than that in Western countries; therefore, data on Japanese pediatric patients with GD type 1 are currently limited. The present study reports on the case of a Japanese pediatric patient with GD type 1 who was diagnosed when she presented with hepatosplenomegaly, thrombocytopenia and slight anemia at the age of 2 years. Serology tests revealed high levels of acid phosphatase (ACP) and angiotensin-converting enzyme (ACE). A bone marrow biopsy revealed the presence of Gaucher cells. Abdominal MRI indicated huge hepatosplenomegaly. Erlenmeyer flask deformity was observed on X-ray examination. MRI of the femora featured a high-intensity area within the diaphysis region. The enzymatic activity of leukocyte β-glucosidase, the measurement of which is necessary for a definitive diagnosis of GD, had decreased to 186.7 nmol/h/mg (reference range, 1,424.0-2,338.0 nmol/h/mg). Based on these results, the patient was clinically diagnosed with GD. Glucocerebrosidase gene analysis identified the compound heterozygote mutation of F213I (c.754T>A) on exon 7 and L444P (c.1448T>C) on exon 11. Enzyme replacement therapy (ERT) along with an intravenous infusion of 60 U/kg of imiglucerase every other week was initiated following diagnosis. Hemoglobin levels and the platelet count gradually improved and normalized after two years. ACP and ACE levels, biomarkers of the progression of GD, also improved. Abdominal MRI at six months after the initiation of ERT revealed a decrease in the size of the liver and spleen, which normalized after 1 year. Conversely, MRI of the femora indicated no improvement in the high-intensity area within the diaphysis region for 10 years.

Symmetric, bilateral upper and lower extremity lucent lesions in a patient with Gaucher's disease on enzyme replacement therapy

We report a case of a 6-year old girl with known type 3 Gaucher's Disease on enzyme replacement therapy who developed bilateral, symmetric osteolytic lesions in her humeri and femurs. While this manifestation of Gaucher's disease has been previously documented, it is an exceedingly rare variation. We observe that this patient shares 2 commonalities with 3 other patients reported in the literature to present with this phenotype. First, the patient's L444P/L444P genotype, present in approximately 11% of all Gaucher's patients, was also seen in these other patients. Second, like the other patients, this patient was treated with enzyme replacement therapy. It is unknown whether there is a correlation between these 2 independent variables and this rare phenotype, and further investigation may be warranted.

A Quantitative Systems Pharmacology Model of Gaucher Disease Type 1 Provides Mechanistic Insight Into the Response to Substrate Reduction Therapy With Eliglustat

Gaucher’s disease type 1 (GD1) leads to significant morbidity and mortality through clinical manifestations, such as splenomegaly, hematological complications, and bone disease. Two types of therapies are currently approved for GD1: enzyme replacement therapy (ERT), and substrate reduction therapy (SRT). In this study, we have developed a quantitative systems pharmacology (QSP) model, which recapitulates the effects of eliglustat, the only first‐line SRT approved for GD1, on treatment‐naïve or patients with ERT‐stabilized adult GD1. This multiscale model represents the mechanism of action of eliglustat that leads toward reduction of spleen volume. Model capabilities were illustrated through the application of the model to predict ERT and eliglustat responses in virtual populations of adult patients with GD1, representing patients across a spectrum of disease severity as defined by genotype‐phenotype relationships. In summary, the QSP model provides a mechanistic computational platform for predicting treatment response via different modalities within the heterogeneous GD1 patient population.

Acoustic radiation force impulse point shear wave elastography of the liver and spleen in patients with Gaucher disease type 1: Correlations with clinical data and markers of disease severity

PURPOSE

To evaluate the feasibility of acoustic radiation force impulse point shear wave elastography (ARFI-pSWE) of the liver and spleen in patients with Gaucher disease type 1 (GD1), and to assess correlations between organ stiffness and clinico-radiologic data, particularly the GD1 Severity Scoring System (GD-DS3).

MATERIALS AND METHODS

We retrospectively evaluated the results of ARFI-pSWE as measures of liver and spleen stiffness in 57 patients with GD1. The feasibility of the method was assessed. Correlations between elastography data and clinical data related to the metabolic syndrome, laboratory tests, and GD1-related clinico-radiologic data (bone marrow burden score, GD-DS3) were assessed.

RESULTS

ARFI-pSWE provided reliable results (i.e. standard deviation <30% of the mean value between the measurements) in 50/57 patients. Significant liver fibrosis was present in 35/50 patients (70%). Liver stiffness significantly correlated with GD-DS3 score (p = .03), and number of fulfilled criteria of metabolic syndrome (p = .03). Spleen stiffness significantly correlated with age (p = .021), body mass index (p = .002), number of fulfilled criteria of metabolic syndrome (p = .02), and several laboratory parameters (alanine aminotransferase, gamma glutamyltranspeptidase, triglycerides, cholesterol), and nearly significantly with GD-DS3 score (p = .059).

CONCLUSION

ARFI-pSWE is a useful tool for a more detailed assessment of disease severity in patients with GD1, which adds relevant information to the standard clinical scores. Thus, elastography might allow for extended therapy monitoring, especially in patients with significant liver fibrosis. Spleen elastography showed promising results; thus, its role should be further investigated.

Evaluation of the efficacy and safety of the biosimilar drug Glurazyme (imiglucerase) in patients with Gaucher disease type 1

Background. Gaucher disease (GD) is a rare hereditary condition, which represents the most common form of lysosomal storage diseases. Enzyme replacement therapy (ERT) with recombinant glucocerebrosidase is used for the treatment of type 1 and type 3 GD. Imiglucerase (recombinant glucocerebrosidase) is the first biotechnological ERT medication possessing confirmed clinical efficacy and safety.

Aim. To compare the efficacy and safety of the biosimilar drug Glurazyme and the reference drug Cerezyme during ERT therapy in patients with type 1 GD.

Materials and methods. Thirty patients aged from 19 to 63 years (33 ± 9.7 years) with a stable course of type 1 GD were enrolled in the study. The patients were randomly divided into two equal treatment groups, one of which received Glurazyme and the other received the reference drug Cerezyme. In both groups, the drugs were used in doses of 15–40 U/kg intravenously once every 14 days for 52 weeks.

Results. At the end of the study, at week 52 (primary endpoint of efficacy), both groups demonstrated a similar increase in hemoglobin concentration compared to the baseline data. In both groups, the average increase in hemoglobin concentration was 4.8 g/l, with this parameter varying between the groups by 0.1 g/l. At week 52, the calculated 95% confidence interval for the difference in hemoglobin concentration did not cross the non-inferiority margin of 18 g/l, which had been specified as the lower level of drug efficacy. This led to the conclusion that the studied drug Glurazyme is not inferior to Cerezyme in terms of efficacy. A comparison of the treatment groups by secondary endpoints of efficacy revealed: no decrease in hemoglobin concentration by more than 20 % in both groups; no differences between the groups by the number of patients with a change in platelet concentration relative to the baseline values; no increase in the spleen and liver volume by more than 20 and 10 %, respectively, in both groups. The doses of the drug under study and the reference drug remained unchanged during the research. The concentration of chemokine CCL-18 decreased slightly in 10 patients (64.3 %) and 6 patients (40 %) in the Glurazyme group and the Cerezyme group, respectively. The proportion of patients with improved physical and mental health components was 57.1 and 57.1 %, respectively, in the Glurazyme group compared to 73.3 and 60 %, respectively, in the Cerezyme group. Changes in the state of the bone tissue and the reserves of accumulated metabolites in the bone marrow showed a similar decrease in the severity of bone marrow infiltration in both groups.

Conclusions. Glurazyme and Cerezyme showed comparable parameters of efficacy and safety in patients with GD type 1 during long-term enzyme replacement therapy.

Glucosylsphingosine (lyso-Gb1) as a Biomarker for Monitoring Treated and Untreated Children with Gaucher Disease

The role of glucosylsphingosine (lyso-Gb1), a downstream metabolic product of glucosylceramide, for monitoring treated and untreated children with Gaucher disease (GD) has not yet been studied. We reviewed the clinical charts of 81 children (<18 years), 35 with mild type 1 GD (GD1), 34 with severe GD1 and 12 with type 3 GD (GD3), followed at Shaare Zedek Medical Center between 2014-2018. Disease severity for GD1 was based on genotypes. Forty children (87%) with severe GD1 and GD3 received enzyme replacement therapy (ERT) compared to two children (6%) with mild GD1. Lyso-Gb1 measurements were conducted on dried blood spot samples taken at each clinic visit. Lyso-Gb1 levels were significantly lower in children with mild compared to severe GD1 (p = 0.009). In untreated children, lyso-Gb1 levels were inversely correlated with platelet counts. During follow-up, lyso-Gb1 increased in almost 50% of untreated children, more commonly in younger children. In treated children, lyso-Gb1 levels were inversely correlated with hemoglobin levels. The increase of lyso-Gb1 while receiving ERT, seen in eight children, was partly associated with compliance and weight gain. Lyso-Gb1 seems to be a useful biomarker for monitoring children with GD and should be included in the routine follow-up. Progressive increase in lyso-Gb1 levels in untreated children suggests ERT initiation.

Gaucher Disease in Bone: From Pathophysiology to Practice

Gaucher disease (GD) is a rare, genetic lysosomal disorder leading to lipid accumulation and dysfunction in multiple organs. Involvement of the skeleton is one of the most prevalent aspects of GD and a major cause of pain, disability, and reduced quality of life. Uniform recommendations for contemporary evaluation and management are needed. To develop practical clinical recommendations, an international group of experienced physicians conducted a comprehensive review of 20 years' of the literature, defining terms according to pathophysiological understanding and pointing out best practice and unmet needs related to the skeletal features of this disorder. Abnormalities of bone modeling, reduced bone density, bone infarction, and plasma cell dyscrasias accompany the displacement of healthy adipocytes in adult marrow. Exposure to excess bioactive glycosphingolipids appears to affect hematopoiesis and the balance of osteoblast and osteoclast numbers and activity. Imbalance between bone formation and breakdown induces disordered trabecular and cortical bone modeling, cortical bone thinning, fragility fractures, and osteolytic lesions. Regular assessment of bone mineral density, marrow infiltration, the axial skeleton and searching for potential malignancy are recommended. MRI is valuable for monitoring skeletal involvement: It provides semiquantitative assessment of marrow infiltration and the degree of bone infarction. When MRI is not available, monitoring of painful acute bone crises and osteonecrosis by plain X-ray has limited value. In adult patients, we recommend DXA of the lumbar spine and left and right hips, with careful protocols designed to exclude focal disease; serial follow-up should be done using the same standardized instrument. Skeletal health may be improved by common measures, including adequate calcium and vitamin D and management of pain and orthopedic complications. Prompt initiation of specific therapy for GD is crucial to optimizing outcomes and preventing irreversible skeletal complications. Investing in safe, clinically useful, and better predictive methods for determining bone integrity and fracture risk remains a need. © 2019 The Authors. Journal of Bone and Mineral Research Published by Wiley Periodicals Inc.

GBA, Gaucher Disease, and Parkinson's Disease: From Genetic to Clinic to New Therapeutic Approaches

Parkinson’s disease (PD) is the second most common degenerative disorder. Although the disease was described more than 200 years ago, its pathogenetic mechanisms have not yet been fully described. In recent years, the discovery of the association between mutations of the GBA gene (encoding for the lysosomal enzyme glucocerebrosidase) and PD facilitated a better understating of this disorder. GBA mutations are the most common genetic risk factor of the disease. However, mutations of this gene can be found in different phenotypes, such as Gaucher’s disease (GD), PD, dementia with Lewy bodies (DLB) and rapid eye movements (REM) sleep behavior disorders (RBDs). Understanding the pathogenic role of this mutation and its different manifestations is crucial for geneticists and scientists to guide their research and to select proper cohorts of patients. Moreover, knowing the implications of the GBA mutation in the context of PD and the other associated phenotypes is also important for clinicians to properly counsel their patients and to implement their care. With the present review we aim to describe the genetic, clinical, and therapeutic features related to the mutation of the GBA gene.

Bone manifestations in neuronopathic Gaucher disease while receiving high-dose enzyme replacement therapy

Avascular necrosis (AVN), one type of bone infarction, is a major irreversible complication of Gaucher disease (GD). In this report, two pediatric patients with GD type 3, homozygous for the L483P pathogenic variant (formerly L444P), developed AVN despite treatment on long-term, high-dose enzyme replacement therapy (ERT). ERT was initiated in both patients, who had intact spleens, shortly after diagnosis with an initial dramatic response. However, both patients exhibited AVN after 5.5 and 11 years on high-dose ERT, respectively, despite good compliance and normalized hematological findings and visceral symptoms. This report demonstrates the importance of careful, regular surveillance of the musculoskeletal system in addition to monitoring the neurological symptoms associated with neuronopathic GD. Additionally, it highlights the limitations of ERT in terms of targeting certain sanctuary sites such as bone marrow and suggests the need for new treatment modalities other than ERT monotherapy to address these limitations.

Pharmacological treatment of pediatric Gaucher disease

INTRODUCTION

Gaucher disease (GD) is an autosomal recessive disorder resulting from the deficiency of the lysosomal enzyme glucocerebrosidase (b-glucosidase), associated with varying degrees of visceral, bone and central nervous system pathology, leading to wide phenotypic diversity. Response to therapy and clinical outcomes are very different between the three clinical subtypes - non-neuronopathic, acute neuronopathic, and chronic neuronopathic forms; hence a definitive clinical diagnosis is essential. The availability of two therapeutic options, i.e. enzyme replacement and substrate reduction, has transformed the natural course of the disease. As pre-treatment disease severity clearly impacts results of therapy, early diagnosis and initiation of treatment especially in the pediatric population are keys to achieving an optimal outcome. Areas covered: We reviewed the literature concerning the treatment of GD focusing on pediatric presentations, various pharmacological treatment options and recommendations for management goals. A PubMed literature search was performed for relevant publications between 1991 and September 2018. Expert commentary: The approval of enzyme replacement therapy (ERT) for GD in the pediatric age group has significantly altered the course of the disease, especially for non-neuronopathic and chronic neuronopathic forms, as ERT does not cross the blood-brain barrier. Early diagnosis, regular follow-up and early initiation of treatment can thus prevent some irreversible complications and improve patient quality of life.

How we manage Gaucher Disease in the era of choices

Treatment of Gaucher Disease (GD) is now beset with the abundance of therapeutic options for an individual patient, making the choice of therapy complex for both expert and non-expert clinicians. The pathogenesis of all disease manifestations is a gene mutation-driven deficiency of glucocerebrosidase, but the clinical expression and response of each of the clinical manifestations to different therapies can be difficult to predict. Enzyme replacement therapy has been available since 1991 and is well-established, with known efficacy and minimal toxicity. Of interest, the three available enzymes are distinct molecules and were registered as new products, not biosimilars. Oral substrate reduction therapy has undergone a revitalisation with a newly approved agent in this class for which some efficacy and toxicity questions have been raised. Herein we present our approach to the management of GD in the era of choices, including a new algorithm for how to manage a newly diagnosed patient.

Recent advances in the diagnosis and management of Gaucher disease

INTRODUCTION

Gaucher disease, the autosomal recessive deficiency of the lysosomal enzyme glucocerebrosidase, is associated with wide phenotypic diversity including non-neuronopathic, acute neuronopathic, and chronic neuronopathic forms. Overlap between types can render definitive diagnoses difficult. However, differentiating between the different phenotypes is essential due to the vast differences in clinical outcomes and response to therapy. Genotypic information is helpful, but cannot always be used to make clinical predictions. Current treatments for Gaucher disease, including enzyme replacement therapy and substrate reduction therapy, can reverse many of the non-neurological manifestations, but these therapies must be administered continually and are extremely costly.

AREAS COVERED

We reviewed the literature concerning the varied clinical presentations of Gaucher disease throughout the lifetime, along with treatment options, management goals, and current and future research challenges. A PubMed literature search was performed for relevant publications between 1991 to January 2018.

EXPERT COMMENTARY

Interest and research in the field of Gaucher disease is rapidly expanding. However, significant barriers remain in our ability to predict phenotype, assess disease progression using objective biomarkers, and determine optimal treatment strategy on an individual basis. As the field grows, we anticipate identification of genetic modifiers, new biomarkers, and small-molecule chaperone therapies, which may improve patient quality of life.

In vitro osteoclastogenesis from Gaucher patients' cells correlates with bone mineral density but not with Chitotriosidase

Gaucher disease (GD) is caused by mutations on the gene encoding for the lysosomal enzyme glucocerebrosidase. Type I GD (GD1) patients present anemia, hepatosplenomegaly and bone alterations. In spite of treatment, bone alterations in GD patients persist, including poor bone mineral density (BMD). Mechanisms leading to bone damage are not completely understood, but previous reports suggest that osteoclasts are involved. Chitotriosidase (CHIT) is the most reliable biomarker used in the follow up of patients, although its correlation with bone status is unknown. The aim of this work was to study the pro-osteoclastogenic potential in patients and to evaluate its correlation with CHIT activity levels and clinical parameters. PBMCs from treated patients and healthy controls were cultured in the presence of M-CSF, and mature osteoclasts were counted. BMD, blood CHIT activity and serum levels of CTX, BAP, and cytokines were evaluated in patients. We found that blood CHIT activity and osteoclast differentiation were significantly increased in patients, but no correlation between them was observed. Interestingly, osteoclast numbers but not CHIT, presented a negative correlation with BMD expressed as Z-score. CTX, BAP and serum cytokines involved in bone remodeling were found altered in GD1 patients. These results show for the first time a correlation between osteoclast differentiation and BMD in GD1 patients, supporting the involvement of osteoclasts in the bone pathology of GD1. Our results also suggest that an altered immune response may play an important role in bone damage.

Transformation in pretreatment manifestations of Gaucher disease type 1 during two decades of alglucerase/imiglucerase enzyme replacement therapy in the International Collaborative Gaucher Group (ICGG) Gaucher Registry

This study tests the hypothesis that the prevalence of severe clinical manifestations in Gaucher disease type 1 (GD1) patients at the time of treatment initiation has changed since alglucerase/imiglucerase enzyme replacement therapy (ERT) was approved in the United States (US) in 1991. US alglucerase/imiglucerase‐treated GD1 patients from the International Collaborative Gaucher Group Gaucher Registry clinicaltrials.gov NCT00358943 were stratified by age at ERT initiation (<18, 18 to <50, ≥50 years), era of ERT initiation (1991‐1995, 1996‐2000, 2001‐2005, 2006‐2009), and splenectomy status pre‐ERT. Prevalence of splenectomy decreased dramatically across the eras among all age groups. Bone manifestations were more prevalent in splenectomized patients than non‐splenectomized patients in all age groups. Prevalence of bone manifestations differed across eras in certain age groups: non‐splenectomized patients had a lower prevalence of ischemic bone events (pediatric patients) and bone crisis (pediatric patients and adults 18 to <50 years) in later eras; splenectomized adult (18 to <50 years) patients had a lower prevalence of ischemic bone events and bone crisis in later eras. Over two decades after the introduction of ERT, the prevalence of splenectomy and associated skeletal complications has declined dramatically. Concomitantly, the interval between diagnosis and initiation of ERT has decreased, most strikingly in pediatric patients who have the most severe disease. Together, these findings suggest that since the introduction of alglucerase/imiglucerase ERT, optimal standard of care has become established in the US to prevent destructive complications of GD1.

Skeletal involvement in type 1 Gaucher disease: Not just bone mineral density

Gaucher disease is characterized by multi-organ infiltration of phospholipid-laden macrophages. Bone involvement is characterized by typical deformities, osteopenia/osteoporosis, pathological fractures, and bone marrow infiltration (avascular osteonecrosis, infarction). Estimation of skeletal disease includes bone quality that contributes substantially to bone strength. We studied 23 type 1 Gaucher patients (median age 22years, range 3-73) on Enzyme Replacement Therapy from 2months to 26years (median 7years); 4 patients had pathological fractures, 10 bone infarctions, 6 avascular osteonecrosis. We noninvasively assessed bone quality by trabecular microarchitecture and macroscopic geometry, using two innovative dual-energy X-ray absorptiometry tools: Trabecular Bone Score (TBS) and Hip Structural Analysis (HSA). Bone quality parameters distinguished the patients with skeletal complications. TBS was significantly lower in patients with avascular osteonecrosis (p=0.049) and pathological fractures (p=0.024), while it could not identify those with bone infarctions. Among HSA parameters, the Cross Sectional Area of the intertrochanteric region and the Buckling Ratio of the narrow neck allowed the distinction of patients with avascular osteonecrosis. BMD was low in 11 patients (50%); neither BMD nor HSA were associated with pathological fractures. The combined evaluation of bone quality and bone quantity is useful to identify GD patients with more severe skeletal involvement.

Spotlight on taliglucerase alfa in the treatment of pediatric patients with type 1 Gaucher disease

Gaucher disease (GD) is a heritable storage disorder caused by functional defects of the lysosomal acid β-glucosidase and the accumulation of glucosylceramide within macrophages, resulting in multiple organ dysfunction. There are three commercially available enzyme replacement therapy (ERT) products for the treatment of GD type 1 (GD1): imiglucerase, velaglucerase alfa, and taliglucerase alfa. Imiglucerase and velaglucerase alfa are produced in different mammalian cell systems; imiglucerase requires postproduction deglycosylation to expose terminal α-mannose residues, which are required for mannose receptor-mediated uptake by target macrophages. These steps are critical to the success of ERT for the treatment of visceral and hematologic manifestations of GD. Taliglucerase alfa is the first US Food and Drug Administration-approved plant-cell-expressed recombinant human protein, using carrot root cell cultures. Furthermore, it does not require postproduction glycosidic modifications. It is indicated for treatment of adults with GD1 in the US, Israel, Australia, Canada, Chile, Brazil, and other countries, and it is additionally approved for the treatment of pediatric patients in the US, Australia, and Canada and for the treatment of hematologic manifestations in pediatric patients with Type 3 GD in Canada and other countries. Our review focuses on the role of taliglucerase alfa in the pediatric population. A literature search through PubMed (from 1995 up till November 2016) of English language articles was performed with the following terms: Gaucher disease, lysosomal storage disease, taliglucerase. Secondary and tertiary references were obtained by reviewing related articles as well as the website www.Clinicaltrials.gov. It has been demonstrated that taliglucerase alfa is efficacious, with a well-established safety profile in pediatric, ERT-naïve patients with symptomatic GD1, as well as for those patients previously treated with imiglucerase.

Diagnosis features of pediatric Gaucher disease patients in the era of enzymatic therapy, a national-base study from the Spanish Registry of Gaucher Disease

BACKGROUND

The enzymatic replacement therapy (ERT) availability for Gaucher disease (GD) has changed the landscape of the disease, several countries have screening programs. These actions have promoted the early diagnosis and avoided many complications in pediatric patients. In Spain ERT has been available since 1993 and 386 patients have been included in the Spanish Registry of Gaucher Disease (SpRGD). The aim of this study is to analyze the impact of ERT on the characteristics at time of diagnosis and initial complications in pediatric Gaucher disease patients.

AIM

To analyze the impact of ERT on the characteristics at time of diagnosis and initial complications in pediatric Gaucher disease patients.

METHODS

A review of data in SpRGD from patients' diagnosed before 18 years old was performed. The cohort was split according the year of diagnosis (≤1994, cohort A; ≥1995, cohort B).

RESULTS

A total of 98 pediatric patients were included, GD1: 80, GD3: 18; mean age: 7.2 (0.17-16.5) years, 58 (59.2%) males and 40 (40.8%) females. Forty-five were diagnosed ≤ 1994 and 53 ≥ 1995. Genotype: N370S/N370S: 2 (2.0%), N370S/L444P: 27 (27.5%), N370S/other: 47 (48%), L444P/L444P: 7 (7.1%), L444P/D409H: 2 (2.0%), L444P/other: 3 (6.2%), other/other: 10 (10.2%). The mean age at diagnosis was earlier in patients diagnosed after 1995 (p < 0.001) and different between the subtypes, GD1: 8.2 (0.2-16.5) years and GD3: 2.8 (0.17-10.2) years (p < 0.001). There were more severe patients in the group diagnosed before 1994 (p = 0.045) carrying L444P (2), D409H (2), G377S (1), G195W (1) or the recombinant mutation. The patients' diagnosed ≤1994 showed worse cytopenias, higher chance of bone vascular complications at diagnosis and previous spleen removal. The patients started ERT at a median time after diagnosis of 5.2 years [cohort A] and 1.6 years [cohort B] (p < 0.001).

CONCLUSIONS

The early diagnosis of Gaucher disease in the era of ERT availability has permitted to reduce the incidence of severe and irreversible initial complication in pediatric patients, and this has permitted better development of these patients. This is the largest pediatric cohort from a national registry.

Ten plus one challenges in diseases of the lysosomal system

The advent of the first effective specific therapy for a lysosomal storage disease (LSDs), Gaucher disease type 1, by Roscoe O. Brady was foundational for development of additional treatments for this group of rare diseases. The past 26years, since the approval of enzyme therapy for Gaucher disease type 1, have witnessed a burgeoning understanding of LSDs at genetic, molecular, biochemical, cell biologic, and clinical levels. Simultaneously, this expansion of knowledge has exposed our incomplete understanding of the individual pathophysiologies of LSDs as well as difficult challenges for improvement in therapy and therapeutic outcomes for afflicted individuals. Here, 10 such challenges/problems representing major impediments, which need to be overcome, to move forward toward the goals of more effective and complete therapies for these devastating diseases.

Long-term hematological, visceral, and growth outcomes in children with Gaucher disease type 3 treated with imiglucerase in the International Collaborative Gaucher Group Gaucher Registry

In Gaucher disease (GD), deficiency of lysosomal acid β-glucosidase results in a broad phenotypic spectrum that is classified into three types based on the absence (type 1 [GD1]) or presence and severity of primary central nervous system involvement (type 2 [GD2], the fulminant neuronopathic form, and type 3 [GD3], the milder chronic neuronopathic form). Enzyme replacement therapy (ERT) with imiglucerase ameliorates and prevents hematological and visceral manifestations in GD1, but data in GD3 are limited to small, single-center series. The effects of imiglucerase ERT on hematological, visceral and growth outcomes (note: ERT is not expected to directly impact neurologic outcomes) were evaluated during the first 5years of treatment in 253 children and adolescents (<18years of age) with GD3 enrolled in the International Collaborative Gaucher Group (ICGG) Gaucher Registry. The vast majority of GBA mutations in this diverse global population consisted of only 2 mutations: L444P (77%) and D409H (7%). At baseline, GD3 patients exhibited early onset of severe hematological and visceral disease and growth failure. During the first year of imiglucerase treatment, hemoglobin levels and platelet counts increased and liver and spleen volumes decreased, leading to marked decreases in the number of patients with moderate or severe anemia, thrombocytopenia, and hepatosplenomegaly. These improvements were maintained through Year 5. There was also acceleration in linear growth as evidenced by increasing height Z-scores. Despite devastating disease at baseline, the probability of surviving for at least 5years after starting imiglucerase was 92%. In this large, multinational cohort of pediatric GD3 patients, imiglucerase ERT provided a life-saving and life-prolonging benefit for patients with GD3, suggesting that, with proper treatment, many such severely affected patients can lead productive lives and contribute to society.

DOENÇA DE GAUCHER TIPO 1 NO ESQUELETO: REVISÃO DA AMÉRICA LATINA

RESUMO A doença de Gaucher (DG) é a doença de depósito lisossômico mais prevalente, que se caracteriza pelo acúmulo de glicosilceramida e glucosilesfingosina em todos os tecidos do corpo. Com o advento da terapia de reposição de enzimas, o prognóstico dos pacientes com DG melhorou acentuadamente. Ainda assim, as manifestações esqueléticas associadas à DG respondem lentamente à terapia de reposição de enzimas e são as que contribuem de forma mais significativa para a morbidade do paciente. Esta revisão das manifestações ósseas da DG apresenta as mais recentes teorias sobre a sua fisiopatologia e uma revisão sistemática de estudos com pacientes latino-americanos que relataram a frequência das manifestações ósseas e os efeitos da terapia de reposição de enzimas sobre seu tratamento. Concluímos, destacando a importância da identificação precoce e do manejo adequado das doses apropriadas da terapia de reposição de enzimas para reduzir a morbidade causada pela DG.

Demographic, Clinical and Genetic Characteristics of Child Gaucher Disease Patients in Russia: Pediatric Register Data

Background: Registers are an effective tool for tracing the dynamics of patients with rare pathologies.

Objective: Our aim was to examine the demographic, clinical and genetic features of child Gaucher disease patients in Russia.

Methods: We held a retrospective survey of the pediatric register data with regard to children suffering from Gaucher disease. The period of data accounting was from 2006 to 2016.

Results: 115 children with Gaucher disease aged from 3 months to 17 years (the median age of diagnosis is 5 years) were registered; 62 them (53.9%) are girls. The prevalence of the disease was 0.32 cases for 100,000 children. 95 (82.6%) children had 1st type of Gaucher disease, 6 (5.2%) — 2nd, and 1 (12.2%) — 3rd. Maximum morbidity was in Central (27; 23.5%) and Volga (27; 23.5%) Federal Districts; minimal — in the Far East (3; 2.6%). By the time of diagnosis all the patients were suffering from splengomegaly. The genotype and phenotype correlations in 90 children with Gaucher disease were as follows: in case of 1st type (n = 77), in 21 (27.3%) cases, the p.N370S/р.L444P genotype was set, in 12 (15.6%) — the р.N370S/other mutation; in case of 2nd and 3rd types, in 13 children with neuropathic forms, in 9 (62.9%) cases — the p.L444P/p.L444P, in 3 (231%) — the p.L444P/p. D409H. The rest of genotypes were presented by other mutations, 13 of which were revealed for the first time. The p.W223R (p.W184R) mutation is specific for Russian patients. Enzyme replacement therapy was carried out for 109 patients (94.8%): in 105 (96.3%) children (1st and 3rd types of Gaucher disease) with imiglucerase, in 4 (3.7%) children with 1st type — with velaglucerase alfa. Pathogenetic treatment stops the main symptoms in most patients.

Conclusion: The pediatric Gaucher disease register allows to systemize the data concerning the disease course in children and optimizing the approaches to its monitoring in Russia.

Imiglucerase in the management of Gaucher disease type 1: an evidence-based review of its place in therapy

Introduction

Gaucher disease is the first lysosomal disease to benefit from enzyme replacement therapy, thus serving as model for numerous other lysosomal diseases. Alglucerase was the first glucocerebrosidase purified from placental extracts, and this was then replaced by imiglucerase – a Chinese hamster ovary cell-derived glucocerebrosidase.

Aim

The aim was to review the evidence underlying the use of imiglucerase in Gaucher disease type 1

Evidence review

Data from clinical trials and Gaucher Registries were analyzed.

Conclusion

Imiglucerase has been prescribed and found to have an excellent efficacy and safety profile. We report herein the evidence-based data published for 26 years justifying the use of imiglucerase.

Skeletal involvement in Gaucher disease: An observational multicenter study of prognostic factors in the Argentine Gaucher disease patients

Patients with Gaucher type 1 (GD1) throughout Argentina were enrolled in the Argentine bone project to evaluate bone disease and its determinants. We focused on presence and predictors of bone lesions (BL) and their relationship to therapeutic goals (TG) with timing and dose of enzyme replacement therapy (ERT). A total of 124 patients on ERT were enrolled in a multi-center study. All six TG were achieved by 82% of patients: 70.1% for bone pain and 91.1% for bone crisis. However, despite the fact that bone TGs were achieved, residual bone disease was present in 108 patients on ERT (87%) at time 0. 16% of patients showed new irreversible BL (bone infarcts and avascular osteonecrosis) despite ERT, suggesting that they appeared during ERT or were not detected at the moment of diagnosis. We observed 5 prognostic factors that predicted a higher probability of being free of bone disease: optimal ERT compliance; early diagnosis; timely initiation of therapy; ERT initiation dose ≥45 UI/kg/EOW; and the absence of history of splenectomy. Skeletal involvement was classified into 4 major phenotypic groups according to BL: group 1 (12.9%) without BL; group 2 (28.2%) with reversible BL; group 3 (41.9%) with reversible BL and irreversible chronic BL; and group 4 (16.9%) with acute irreversible BL. Our study identifies prognostic factors for achieving best therapeutic outcomes, introduces new risk stratification for patients and suggests the need for a redefinition of bone TG. Am. J. Hematol. 91:E448-E453, 2016. © 2016 Wiley Periodicals, Inc.

Outcome of Gaucher Disease in India: Lessons from Prevalent Diagnostic and Therapeutic Practices

OBJECTIVE

To study disease severity and response to enzyme replacement therapy in Gaucher disease.

METHODS

Updated data was captured from records of 37 patients (35 reported previously) with confirmed diagnosis of Gaucher disease from January 1995 through December 2011 (31, 83.8 %) and prospectively from January 2012 through June 2013 (6, 16.2 %). Severity of manifestations was determined by Gaucher disease Severity Score Index. Response to enzyme replacement therapy was assessed in terms of attainment of therapeutic goals.

RESULTS

Moderate to severe manifestations (domain score of > 2) were observed in treated patients at baseline (83%, 58%, 66% and 25% for anemia, thrombocytopenia, hepatomegaly and leucopenia, respectively and 100% for splenomegaly and elevated plasma chitotriosidase). None of the 11 patients treated with synthetic enzyme (average annual dose 23 to 53 units/kg) attained all therapeutic goals in the recommended time frame, particularly the visceral, skeletal and growth domains.

CONCLUSION

Early onset of moderate to severe disease in Indian patients mandates early therapy with optimum doses to ensure attainment of all recommended therapeutic goals.

Gaucher disease in Iraqi children (Clinical, diagnostic & therapeutic aspects)

Background and Objective:

Gaucher disease is the most common inherited lysosomal storage disorder. It is a multi organ disease affecting bone marrow, liver, spleen, lungs, and other organs contributes to pancytopenia and massive hepatosplenomegaly. This study aimed to spotlight on clinical and laboratory characteristics of children with Gaucher disease to raise awareness among physicians about the disease and to evaluate the outcome of enzyme replacement therapy (ERT).

Methods:

Clinical courses were reviewed in 30 patients with age (2-22 years) with Gaucher disease. After starting (ERT), assessment of response included serial measurements of hematological parameters, spleen and liver sizes, symptoms and signs of bone disease, growth and severity scores were also evaluated.

Results:

The most presenting age group was (1 – 5) years (60%). Abdominal distension was the most common presenting symptom, Splenomegaly presented in all of the patients. A significant response to ERT was observed, weight and height increased, both liver and spleen sizes decreased. Hemoglobin level normalizedin (67%) of the anemic patients, platelet count normalized in (53.8%)after 6 months from (ERT), the mean of severity scoring index decreased with ERT from (10.2±5.8) to (7.8±5.7) after one year of treatment.

Conclusion:

Using ERT was safe and effective in the reversal of hematological complications and organomegaly in most of the patients.

Recommendations for the use of eliglustat in the treatment of adults with Gaucher disease type 1 in the United States

In Gaucher disease, deficient activity of acid β-glucosidase results in accumulation of its substrates, glucosylceramide and glucosylsphingosine, within the lysosomes of cells primarily in the spleen, liver, bone marrow, and occasionally the lung. The multisystem disease is predominantly characterized by hepatosplenomegaly, anemia, thrombocytopenia, and skeletal disease. Enzyme replacement therapy with recombinant human acid β-glucosidase has been the first-line therapy for Gaucher disease type 1 for more than two decades. Eliglustat, a novel oral substrate reduction therapy, was recently approved in the United States and the European Union as a first-line treatment for adults with Gaucher disease type 1. Eliglustat inhibits glucosylceramide synthase, thereby decreasing production of the substrate glucosylceramide and reducing its accumulation. Although existing recommendations for the care of patients with Gaucher disease remain in effect, unique characteristics of eliglustat require additional investigation and monitoring. A panel of physicians with expertise in Gaucher disease and experience with eliglustat in the clinical trials provide guidance regarding the use of eliglustat, including considerations before starting therapy and monitoring of patients on eliglustat therapy.

Long-term velaglucerase alfa treatment in children with Gaucher disease type 1 naïve to enzyme replacement therapy or previously treated with imiglucerase

BACKGROUND

Gaucher Disease type 1 (GD1) often manifests in childhood. Early treatment with enzyme replacement therapy (ERT) may prevent disease complications. We report the assessment of velaglucerase alfa ERT in pediatric GD1 patients who participated in a long-term extension study (HGT-GCB-044, ClinicalTrials.gov Identifier NCT00635427).

METHODS

Safety and efficacy were evaluated in pediatric patients receiving velaglucerase alfa 30-60U/kg by intravenous infusion every other week. In addition to key hematological and visceral efficacy assessments, exploratory assessments conducted specifically in pediatric patients included evaluation of height, bone age, bone marrow burden, and Tanner stage of puberty.

RESULTS

The study included 24 pediatric patients. Fifteen patients were naïve to ERT on entry into the preceding trials TKT032 (12-month trial) or HGT-GCB-039 (9-month trial): in the preceding trials, ten of these 15 patients received velaglucerase alfa and five patients received imiglucerase ERT. Nine patients in the study were previously treated with imiglucerase for >30months and were switched to velaglucerase alfa in the preceding trial TKT034 (12-month trial). Cumulative ERT exposure in the clinical studies ranged from 2.0 to 5.8years. Three serious adverse events, including a fatal convulsion, were reported; none were deemed related to velaglucerase alfa. One patient tested positive for anti-velaglucerase alfa antibodies. An efficacy assessment at 24months showed that velaglucerase alfa had positive effects on primary hematological and visceral parameters in treatment-naïve patients, which were maintained with longer-term treatment. Disease parameters were stable in patients switched from long-term imiglucerase ERT. Exploratory results may suggest benefits of early treatment to enable normal growth in pediatric patients.

CONCLUSION

The safety profile and clinical response seen in pediatric patients are consistent with results reported in adults.

A multicenter, open-label extension study of velaglucerase alfa in Japanese patients with Gaucher disease: Results after a cumulative treatment period of 24months

Enzyme replacement therapy (ERT) with exogenous glucocerebrosidase is indicated to treat symptomatic Gaucher disease (GD), a rare, inherited metabolic disorder. ERT with velaglucerase alfa, which is produced in a human cell line using gene activation technology, was studied in a 12-month phase III trial in Japanese patients with type 1 or 3 GD who were switched from imiglucerase ERT (n=6); the current, open-label, 12-month extension study was designed to assess longer-term safety and efficacy. Two adult and three pediatric patients (aged <18years) were enrolled into the extension study. Every-other-week intravenous infusions were administered for 63-78weeks at average doses between 51.5 and 60.7units/kg. Three non-serious adverse events were considered related to velaglucerase alfa treatment, but no patient discontinued from the study. Six serious but non-drug-related adverse events were reported. No patient tested positive for anti-velaglucerase alfa antibodies. Hemoglobin concentrations, platelet counts, and liver and spleen volumes (normalized to body weight) in these patients were generally stable over a cumulative 24-month period from the baseline of the parent trial. The data suggest that velaglucerase alfa was well tolerated and maintained clinical stability in Japanese GD patients over 2years after switching from imiglucerase. ClinicalTrials.gov identifier NCT01842841.

Quantification of Bone Marrow Involvement in Treated Gaucher Disease With Proton MR Spectroscopy: Correlation With Bone Marrow MRI Scores and Clinical Status

OBJECTIVE

The objective of our study was to use proton MR spectroscopy (MRS) to quantitatively evaluate bone marrow infiltration by measuring the fat fraction (FF) and to compare the FF with semiquantitative bone marrow MRI scores and clinical status in children treated for type 1 Gaucher disease (GD).

SUBJECTS AND METHODS

Over a 2-year period, we prospectively evaluated 10 treated GD patients (six males, four females; median age, 15.1 years) and 10 healthy age-matched control subjects (five males, five females; median age, 15.3 years) using 3-T proton MRS of L5 and the femoral neck. Water and lipid AUCs were measured to calculate the FF. Two blinded pediatric musculoskeletal radiologists performed a semiquantitative analysis of the conventional MR images using the bone marrow burden score and modified Spanish MRI score. We evaluated symptoms, spleen and liver volumes, platelet levels, hemoglobin levels, and bone complications.

RESULTS

In the femur, the FF was higher in the control subjects (median, 0.71) than the GD patients (0.54) (p = 0.02). In L5, the difference in FF--higher FF in control subjects (0.37) than in GD patients (0.26)--was not significant (p = 0.16). In both groups and both regions, the FF increased with patient age (p < 0.02). Semiquantitative scores showed no differences between control subjects and treated GD patients (p > 0.11). Eight of 10 GD patients were asymptomatic and two had chronic bone pain. The median age of patients at symptom onset was 4.0 years, the median age of patients at the initiation of enzyme replacement therapy was 4.3 years, and the median treatment duration was 10.2 years. Hemoglobin level, platelet count, and liver volume at MRI were normal. Mean pretreatment spleen volume (15.4-fold above normal) decreased to 2.8-fold above normal at the time of MRI (p = 0.01).

CONCLUSION

Proton MRS detected FF differences that were undetectable using conventional MRI; for that reason, proton MRS can be used to optimize treatment of GD patients.

Long-term treatment outcomes in Gaucher disease

Following the treatment of the first Gaucher disease patient with enzyme replacement therapy (ERT), it was clear that ERT had the potential to be transformative with dramatic improvements in systemic manifestations of the disease within 2 years. Following over 20 years existence of the International Collaborative Gaucher Group Gaucher Registry and evidence from ∼6000 patients, the long-term effects of therapy have been documented. It has been shown that ERT can result in improvements in all clinical and laboratory parameters of nonneuronopathic disease. However, different aspects of the disease, such as hematologic parameters, organ volumes and bone disease do not necessarily respond to therapy at the same rate or to the same extent, and this has had major implications for disease monitoring and for the establishment of therapeutic goals for ERT. Response may be affected by factors such as the timing of therapy initiation, the presence of irreversible complications such as osteonecrosis, and by enzyme dose. It is also apparent that ERT has no impact on neurological aspects of disease and highlights the need for additional or alternative treatment strategies able to meet the needs of patients with neuronopathic disease.

Velaglucerase alfa (VPRIV) enzyme replacement therapy in patients with Gaucher disease: Long-term data from phase III clinical trials

Type 1 Gaucher disease is an inherited lysosomal enzyme deficiency with variable age of symptom onset. Common presenting signs include thrombocytopenia, anemia, hepatosplenomegaly, bone abnormalities, and, additionally in children, growth failure. Fifty-seven patients aged 3–62 years at the baseline of two phase III trials for velaglucerase alfa treatment were enrolled in the single extension study. In the extension, they received every-other-week velaglucerase alfa intravenous infusions for 1.2–4.8 years at 60 U/kg, although 10 patients experienced dose reduction. No patient experienced a drug-related serious adverse event or withdrew due to an adverse event. One patient died following a convulsion that was reported as unrelated to the study drug. Only one patient tested positive for anti-velaglucerase alfa antibodies. Combining the experience of the initial phase III trials and the extension study, significant improvements were observed in the first 24 months from baseline in hematology variables, organ volumes, plasma biomarkers, and, in adults, the lumbar spine bone mineral density Z-score. Improvements were maintained over longer-term treatment. Velaglucerase alfa had a good long-term safety and tolerability profile, and patients continued to respond clinically, which is consistent with the results of the extension study to the phase I/II trial of velaglucerase alfa. EudraCT number 2008-001965-27; http://www.clinicaltrials.gov identifier NCT00635427. Am. J. Hematol. 90:584–591, 2015. © 2015 Wiley Periodicals, Inc.

Gaucher disease types 1 and 3: Phenotypic characterization of large populations from the ICGG Gaucher Registry

Study of the natural history of Gaucher disease has revealed marked phenotypic variation. Correlations to genotypes could provide insight into individual susceptibility to varying disease severity, which may impact whole-life medical care, reproductive decisions, and therapeutic choices for affected families. Importantly, pre-symptomatic or prospective interventions or the use of therapies with significant risk require accurate risk-benefit analyses based on the prognosis for individual patients. The body of international data held within the International Collaborative Gaucher Group (ICGG) Gaucher Registry provides an unprecedented opportunity to characterize the phenotypes of Gaucher disease types 1 and 3 and to appreciate demographic and ethnic factors that may influence phenotypes. The diversity of GBA gene mutations from patients with Gaucher disease represented in the ICGG Gaucher Registry database and in the literature provides the basis for initial genotype/phenotype correlations, the outcomes of which are summarized here.