Correlation of bone marrow response with hematological, biochemical, and visceral responses to enzyme replacement therapy of nonneuronopathic (type 1) Gaucher disease in 30 adult patients

Incremental biomarker and clinical outcomes after switch from enzyme therapy to eliglustat substrate reduction therapy in Gaucher disease

In Gaucher disease (GD), genetic deficiency of acid β-glucosidase leads to accumulation of its substrate glucosylceramide (GlcCer) and glucosylsphingosine (GlcSph). Lipid-laden cells, most prominently seen as macrophages engorged with GlcCer and GlcSph-laden lysosomes, trigger chronic metabolic inflammation and multisystemic phenotypes. Among the pleiotropic effects of inflammatory cascades, the induction of glucosylceramide synthase accentuates the primary metabolic defect. First-line therapies for adults with GD type 1 include Enzyme Replacement Therapy (ERT) and eliglustat Substrate Reduction Therapy (SRT). The ENCORE phase 3 clinical trial of eliglustat demonstrated non-inferiority compared to ERT. It is not known whether switching stable patients from long-term ERT to SRT results in the incremental reversal of the disease phenotype and its surrogate indicators. Herein, we report real-world experience from a single tertiary referral center of 38 adult GD type 1 patients, stable on long-term ERT (mean 13.3 years), who switched to eliglustat SRT (mean 3.1 years). After switch to SRT, there was significant reduction in spleen volume (P = 0.003) while liver volume, which was normal at baseline, remained unchanged. Platelet counts increased significantly (P = 0.026). Concomitantly, there was reduction of three validated biomarkers of Gaucher disease activity: plasma GlcSph decreased from 63.7 ng/ml (95% CI, 37.6-89.8) to 26.1 ng/ml (95% CI, 15.7-36.6) (P < 0.0001); chitotriosidase fell from 1136.6 nmol/ml/h (95% CI, 144.7-2128.6) to 466.9 nmol/ml/h (95% CI, 209.9-723.9) (P = 0.002); and glycoprotein non-metastatic melanoma B (gpNMB) decreased from 59.3 ng/ml (95% CI, 39.7-78.9) to 43.6 ng/ml (95% CI, 30.7-56.6) (P = 0.0006). There were no episodes of avascular necrosis or fractures in patients on SRT. Patients reported favorable experiences of switching from alternate week infusions to oral therapy. Collectively, these results demonstrate that the switch to eliglustat SRT from ERT leads to incremental response, even in stable patients after long-term ERT.

Imaging of non-neuronopathic Gaucher disease: recent advances in quantitative imaging and comprehensive assessment of disease involvement

Gaucher disease is an inherited metabolic disorder resulting in deficiency of lysosomal enzyme β-glucocerebrosidase causing the accumulation of abnormal macrophages (“Gaucher cells”) within multiple organs, most conspicuously affecting the liver, spleen, and bone marrow. As the most common glycolipid metabolism disorder, it is important for radiologists encountering these patients to be familiar with advances in imaging of organ and bone marrow involvement and understand the role of imaging in clinical decision-making. The recent advent of commercially available, reliable, and reproducible quantitative MRI acquisitions to measure fat fractions prompts revisiting the role of quantitative assessment of bone marrow involvement. This manuscript reviews the diverse imaging manifestations of Gaucher disease and discusses more optimal quantitative approaches to ascertain solid organ and bone marrow involvement with an emphasis on future applications of other quantitative methods including elastography.

Laboratory diagnosis and follow-up of Romanian Gaucher disease patients

Background: Gaucher disease (GD) is caused by a recessively inherited deficiency of glucocerebrosidase which is encoded by the GBA gene in which nearly 450 mutations have been described. However, only a few genotype- phenotype correlations have been clearly established. The aim of this study was to investigate molecular features of GD in Romanian patients and to evaluate their impact on treatment response. Material and methods: 69 patients, diagnosed between 1997 and 2014 at our national referral laboratory, were included in this study. Frequent point mutations (N370S, L444P, 84GG, R463C) were detected by amplification and restriction enzyme digestion. Recombinant alleles (recTL, recNciI, recA456P) were screened by DNA sequencing. Plasma chitotriosidase served as a biomarker of disease severity throughout the follow-up period. Results: 66 patients had the non-neuronopathic (type 1) form of GD and 3 had the chronic neuronopathic (type 3) phenotype. We identified 79% of the mutant alleles, among which the most frequent mutations were N370S (54%) and L444P (18%). We found a statistically significant (p<0.001) and moderate to good correlation between the total therapeutic dose and the residual chitotriosidase activity (R = 0.621). After two years of treatment, we noticed statistically significant variations in chitotriosidase activity corresponding to the most frequent genotypes (N370S/ unknown allele, N370S/L444P, N370S/N370S and N370S/R463Q). Conclusions: Allele distribution displayed specific features in Romanian GD patients, such as the high prevalence of the N370S allele. Chitotriosidase activity measurement allowed the investigation of genotype influence on treatment outcome.

Standardization of MRI and Scintigraphic Scores for Assessing the Severity of Bone Marrow Involvement in Adult Patients With Type 1 Gaucher Disease

OBJECTIVE

MRI and (99m)Tc-sestamibi scintigraphy are used to estimate bone marrow infiltration in patients with Gaucher disease (GD), but comparison of data obtained at different institutions is difficult because different scores are employed for semiquantitative assessment. We developed normalized scores for comparing data both within a single method (MRI) and between different methods (MRI versus scintigraphy).

MATERIALS AND METHODS

We evaluated 51 patients with type 1 GD (26 women, 25 men; mean age ± SD, 36.3 ± 10.9 years old). T1- and T2-weighted turbo spin-echo sequences at 1.5 T served to derive the bone marrow burden score (0-16), the vertebra-disk ratio (VDR), the Terk score (0-3), and the Spanish-MRI score (S-MRI, 0-24). Scintigraphy was scored between 0 and 8. Each score was normalized into four categories: 0 = normal, 1 = mild, 2 = intermediate, 3 = severe involvement. Interobserver and intraobserver agreements were evaluated by kappa statistics; nonparametric statistics with Bonferroni correction assessed correlations among the various original and normalized scores.

RESULTS

Interobserver agreement was excellent for the original scores (κ = 0.730-0.843) and even more so for the normalized scores (κ = 0.775-0.940). Intraobserver agreement kappa values ranged from 0.753 to 0.937 for the original scores and 0.851 to 1.000 for the normalized scores. Highly significant correlations were found among the various original scores (r = 0.42-0.86, p values between 0.0296 and < 0.0001), except for VDR versus S-MRI and Terk. Normalization generally induced marginal reductions in statistical significance, whereas S-MRI versus VDR reached statistical significance with the normalized scores.

CONCLUSION

Our data indicate no significant loss of statistical information is caused by the normalization we employed. Our approach therefore facilitates comparison of different scores obtained in different institutions with different imaging modalities.

The prognostic value of the serum ferritin in a southern Brazilian cohort of patients with Gaucher disease

The clinical utility of serum ferritin as a biomarker of disease severity and prognosis in Gaucher disease (GD) is still debated. Here, we aimed to evaluate ferritin and its relation to clinicolaboratory parameters of GD patients seen at the Reference Center for Gaucher Disease of Rio Grande do Sul, Brazil, so as to gather evidence on the utility of ferritin as a biomarker of this condition. A retrospective chart review was performed collecting pre-and posttreatment data from GD patients. Eighteen patients with ferritin levels available before and after treatment were included in the study. Nine of these participants were males, and seventeen had type I GD. All patients were given either enzyme replacement (n = 16) or substrate reduction therapy (n = 2), and ferritin was found to decrease from 756 [318-1441] ng/mL at baseline to 521 [227-626] ng/mL (p=0.025) after 28.8 month soft treatment. Serum ferritin levels did not correlate with measures of disease severity, but showed an association with age at onset of treatment (ρ= 0.880; n = 18; p < 0.001). In conclusion, although serum ferritin did not correlate with disease severity, after a median 28.8 months of treatment, clinical outcomes had clearly improved, and ferritin levels had decreased.

Pleural tuberculosis in a patient with untreated type 1 Gaucher disease

Gaucher disease (GD) is an autosomal recessive glycolipid storage disorder, due to deficiency of the lysosomal enzyme glucocerebrosidase, leading to accumulation of the substrate glucocerebroside in the cells of the macrophage-monocyte system. Patients with GD have alteration in their immune system and impaired microbicidal capacity of mononuclear phagocytes. It has also been demonstrated that monocyte dysfunction may correlate with the plasma glucocerebrosidase concentrations. Tuberculosis (TB) is a major public health problem in developing countries. Pleural TB is one of the most common forms of extra-pulmonary TB. Since immune system can be impaired due to the deficiency of glucocerebrosidase in various ways, TB can be observed in patients with GD especially when left untreated. Cytopenia(s) is also general finding in untreated Gaucher patients, and they may be observed most frequently due to the infiltration of the bone marrow with Gaucher cells together with the additional factor of splenomegaly. We herein present a case of an adult patient with heterozygous untreated GD1, who developed pleural TB complicated by ipsilateral pulmonary fibrosis. Before his admission to our clinic, pleurectomy operation was performed and 4-drug combination anti-TB therapy was initiated including isoniazid, rifampicin, ethambutol and pyrazinamide. Fever complaint was disappeared with anti-TB treatment but he also had fatigue and pain. After initiation of enzyme replacement therapy in addition to anti-TB treatment, clinical and hematological improvement was observed. To our knowledge, this is the first reported case of GD1 with pleural TB.

Value of plasma chitotriosidase to assess non-neuronopathic Gaucher disease severity and progression in the era of enzyme replacement therapy

Gaucher disease (GD) is caused by deficiency of the enzyme glucocerebrosidase catalysing the regular lysosomal degradation of glucosylceramide. In the common non-neuropathic variant of GD, glucosylceramide-laden macrophages (Gaucher cells) accumulate in various tissues. Gaucher cells secrete chitotriosidase, an active chitinase, resulting in increased plasma chitotriosidase levels, which can be sensitively monitored by an enzyme activity assay. Plasma chitotriosidase is a rough estimate of body burden of Gaucher cells. Non-neuronopathic GD is presently treated by enzyme replacement therapy (ERT) and substrate reduction therapy (SRT). We addressed the question whether plasma chitotriosidase acts as (predictive) marker of clinical manifestations in non-neuronopathic GD patients receiving treatment. Reductions in plasma chitotriosidase during therapy correlated with corrections in liver and spleen volumes and showed positive trends with improvements in haemoglobin and platelet count and bone marrow composition. The occurrence of long-term complications and associated conditions such as multiple myeloma, bone complications, Parkinson's disease, hepatocellular carcinoma and pulmonary hypertension positively correlated with the plasma chitotriosidase level pre-therapy, the average plasma chitotriosidase during 3 years of ERT and the residual plasma chitotriosidase after 2 years of ERT. In summary, plasma chitotriosidase is a valuable marker in the assessment and follow-up of GD patients.

Revised recommendations for the management of Gaucher disease in children

Gaucher disease is an inherited pan-ethnic disorder that commonly begins in childhood and is caused by deficient activity of the lysosomal enzyme glucocerebrosidase. Two major phenotypes are recognized: non-neuropathic (type 1) and neuropathic (types 2 and 3). Symptomatic children are severely affected and manifest growth retardation, delayed puberty, early-onset osteopenia, significant splenomegaly, hepatomegaly, thrombocytopenia, anemia, severe bone pain, acute bone crises, and fractures. Symptomatic children with types 1 or 3 should receive enzyme replacement therapy, which will prevent debilitating and often irreversible disease progression and allow those with non-neuropathic disease to lead normal healthy lives. Children should be monitored every 6 months (physical exam including growth, spleen and liver volume, neurologic exam, hematologic indices) and have one to two yearly skeletal assessments (bone density and imaging, preferably with magnetic resonance, of lumbar vertebrae and lower limbs), with specialized cardiovascular monitoring for some type 3 patients. Response to treatment will determine the frequency of monitoring and optimal dose of enzyme replacement. Treatment of children with type 2 (most severe) neuropathic Gaucher disease is supportive. Pre-symptomatic children, usually with type 1 Gaucher, increasingly are being detected because of affected siblings and screening in high-prevalence communities. In this group, annual examinations (including bone density) are recommended. However, monitoring of asymptomatic children with affected siblings should be guided by the age and severity of manifestations in the first affected sibling. Treatment is necessary only if signs and symptoms develop.

CONCLUSION

Early detection and treatment of symptomatic types 1 and 3 Gaucher disease with regular monitoring will optimize outcome. Pre-symptomatic children require regular monitoring. Genetic counseling is important.

Long-term bone mineral density response to enzyme replacement therapy in a retrospective pediatric cohort of Gaucher patients

Osteopenia is described as a relevant sign of bone involvement in Gaucher disease (GD) both in pediatric and adult patients. Furthermore, abnormal bone metabolism is considered to play a role in growth and pubertal delay. To analyze the long-term effect of enzyme replacement therapy (ERT) on bone mineral density (BMD), a retrospective observational study was conducted in a cohort of 18 GD pediatric patients (13 males, 5 females; median age 9.2 years). They received biweekly infusions of 20-60 IU/kg of alglucerase/imiglucerase. Clinical, laboratory and imaging parameters were evaluated every 2 years. According to the International Society of Clinical Densitometry guidelines, a Z-score ≤ -2.0 was considered pathological. Nine patients (group P0) began ERT during infancy and nine (group P1) during puberty. At baseline, in three patients (16.6 %; 1P0, 2P1) Z-score was ≤ -2.0 (range -2.47 to -2.25). In patient P0 it normalized after 2 years, while in the 2P1 patients (splenectomized siblings) it persisted abnormal. The remaining 15 patients (83.4 %) always presented a normal value. In group P0, Z-score improved in infancy but showed a significant decrease during puberty, on the contrary it constantly improved in group P1. Furthermore, at baseline group P0 showed a higher median Z-score than group P1: 0.79 (0.38; 1.50) and -1.61 (-2.25; -1.56) respectively. The use of correct BMD standards to interpret bone loss during pediatric age suggests a limited significance of bone loss in these patients. Moreover, the persistence of residual disease activity may affect normal bone growth during puberty in GD populations.

Minimal disease activity in Gaucher disease: criteria for definition

Gaucher disease type I is a metabolic disorder caused by a genetic deficiency of lysosomal β-glucocerebrosidase that leads to accumulation of glucocerebroside in macrophages, thus causing damage in different organ systems. Enzyme replacement therapy with imiglucerase improves organ impairment and clinical manifestations, but patients differ in response to treatment. While clinical remission is the most desirable therapeutic outcome, a more realistic goal in patients with high disease burden is reasonably good clinical status despite persistence of residual biochemical or imaging abnormalities. Therefore, the concept of minimal disease activity--used in certain haematological or rheumatologic conditions--needs to be introduced in Gaucher disease, with a level of disease activity that patients and physicians consider a useful treatment target. In this paper, we propose specific parameters and criteria for defining minimal disease activity in Gaucher disease and its stability over time, based on three major systemic domains typically involved: haematological, visceral, and skeletal. Biomarker parameters were not included as criteria, because currently they do not adequately reflect disease evolution in individual patients. Neurological and respiratory domains were also excluded, as their involvement per se indicates severe disease unlikely to respond to enzyme replacement therapy and achieve minimal disease status. Our goal in defining minimal disease activity and stability is to identify a tool to facilitate treatment decisions in clinical practice.

Therapeutic approaches to bone pathology in Gaucher disease: past, present and future

Enzyme replacement therapy (ERT) is effective for the treatment of the systemic manifestations of Gaucher disease (GD) and can have a significant impact on skeletal manifestations. Bone involvement is broad and can occur in otherwise clinically asymptomatic individuals. The heterogeneity in GD-related bone disease may implicate multiple pathological processes such as disruption of coordinated bone cell activity, in addition to the physical impact of Gaucher cells causing vascular occlusion. Accumulated data suggests that earlier treatment initiation decreases skeletal complications and that bone disease may require a longer duration of treatment and higher dose than is necessary for organ involvement and hematopoietic manifestations. However, in some patients, bone manifestations persist and even worsen despite ERT, regardless of dose or duration of treatment. Treating skeletal disease should be considered of equal importance as treating visceral and hematologic manifestations. When treatment decisions involve multiple enzyme preparations and other therapeutic modalities such small molecules, the choice should be tailored on an individual basis with continuing evaluation.

Biomarkers in the diagnosis of lysosomal storage disorders: proteins, lipids, and inhibodies

A biomarker is an analyte indicating the presence of a biological process linked to the clinical manifestations and outcome of a particular disease. In the case of lysosomal storage disorders (LSDs), primary and secondary accumulating metabolites or proteins specifically secreted by storage cells are good candidates for biomarkers. Clinical applications of biomarkers are found in improved diagnosis, monitoring disease progression, and assessing therapeutic correction. These are illustrated by reviewing the discovery and use of biomarkers for Gaucher disease and Fabry disease. In addition, recently developed chemical tools allowing specific visualization of enzymatically active lysosomal glucocerebrosidase are described. Such probes, coined inhibodies, offer entirely new possibilities for more sophisticated molecular diagnosis, enzyme replacement therapy monitoring, and fundamental research.

Impact of imiglucerase on the serum glycosylated-ferritin level in Gaucher disease

Gaucher disease (GD) is a lysosomal storage disorder, caused by deficient activity of the enzyme glucocerebrosidase, which can be treated by enzyme-replacement therapy (ERT). No prognostic marker can predict long-term complications of GD but several markers are used in therapeutic monitoring: chitotriosidase, total serum ferritin (TSF), angiotensin-converting enzyme (ACE) and tartrate-resistant acid phosphatase (TRAP). They all increase with disease progression and generally decrease under ERT. This study was undertaken to investigate ferritin glycoforms, i.e., glycosylated ferritin (GF) and non-glycosylated ferritin (NGF) concentrations, as potential markers for the follow-up of GD therapy. GF and NGF determinations for GD patients followed in a single center between 1996 and 2007 were analyzed using two approaches: (1) the serum levels of 12 untreated patients were compared with those of 10 patients after 48 months on ERT; (2) the evolution of serum levels under ERT in 15 patients were analyzed using linear/logarithmic mixed models. TSF and NGF levels did not differed significantly between untreated patients and those on ERT (TSF: 524.5 (range 221.0-2045.0) μg/L vs. 410.5 (range 115.0-1587.0) μg/L, respectively, p=0.72; NGF: 340.0 (range 182.8-1717.8) μg/L vs. 199.9 (range 77.1-649.8) μg/L, p=0.09). The percent GF was significantly lower in untreated patients than in those on ERT (27.0% (range 8.0-51.0) vs. 43.5% (range 22.0-80.0) respectively; p=0.02). The percent GF increased significantly during ERT (slope=0.156% [95% confidence interval (CI), 0.03; 0.29] per month, p=0.01) regardless of whether NGF and TSF significantly decreased during ERT (slope=-1.4% per month [95%CI, -1.9%; -1.0%], p<0.0001; slope=-1.1% [95%CI, -1.6%; -0.6%] per month, p<0.0007, respectively). Thus, GF is low in untreated GD patients. GF and NGF changed significantly under ERT and might be of clinical value for GD management under treatment.

Bone events and evolution of biologic markers in Gaucher disease before and during treatment

INTRODUCTION

Known biomarkers of Gaucher-disease activity are platelets, chitotriosidase, angiotensin-converting enzyme (ACE), tartrate-resistant acid phosphatase (TRAP) and ferritin. The aim of this study was to retrospectively evaluate the frequency of bone events (BE) and biomarker changes during two periods: diagnosis to first enzyme-replacement therapy (ERT) and the latter to the closing date.

METHODS

BE of 62 treated patients, among the 73-patient cohort followed at Beaujon Hospital, Clichy, France, were described with Kaplan-Meier curves, and linear-mixed models were used to analyze their biomarker changes and the influence of several covariates (splenectomy, diagnosis year, genotype, age at diagnosis and sex).

RESULTS

BE occurred before (54 events in 21 patients), but also during, ERT (12 events in 10 patients), with respective frequencies (95% confidence interval) at 10 years of 22.4% (13.3 to 36.3) and 20.0% (10.2 to 36.9). Biomarker slope changes before and during ERT differed significantly for platelets (+190/mm3/year and 7,035/mm3/year, respectively; P < 0.0001) and ferritin (+4% and -14%; P < 0.0001). High ferritin levels and low platelet counts at ERT onset were significantly associated with BE during ERT (P = 0.019 and 0.039, respectively). Covariates significantly influenced biomarker changes (baseline and/or slope): splenectomy affected platelets (baseline and changes), TRAP changes and chitotriosidase changes; diagnosis date influenced ACE and TRAP baseline values; and genotype influenced chitotriosidase baseline and changes.

CONCLUSIONS

Platelet counts and ferritin levels and their slope changes at ERT onset seem to predict BE during treatment. Biomarker baseline values and changes are dependent on several covariables.

Hyperferritinemia and iron overload in type 1 Gaucher disease

Hyperferritinemia occurs in Gaucher disease but its clinical spectrum or its association with systemic iron overload and HFE mutations are not known. In 114 patients with Type 1 Gaucher disease, we determined serum ferritin, transferrin saturation and HFE genotype. The results were correlated with the extent of hepatosplenomegaly, overall Gaucher disease severity score index, and response to enzyme replacement therapy. In a subset of patients with radiological and/or laboratory evidence of systemic iron overload, liver biopsy was performed. There was a mean 3.7-fold elevation of serum ferritin over the upper limit of normal (ULN). Prior splenectomy was associated with most severe hyperferritinemia compared to patients with intact spleen (6.53 x ULN vs. 2.69 x ULN, P = 0.003). HFE genotyping revealed two patients homozygous for H63D mutation and 30% of patients heterozygote carriers of H63D mutation; no patients harbored C282Y mutation; there was no correlation of ferritin with HFE genotype. Ferritin level correlated with liver volume (Pearson correlation coefficient = 0.254, P = 0.035) and it was negatively correlated with hemoglobin (r = -0.315, P = 0.004); there was no relationship with other indicators of Gaucher disease activity. Enzyme replacement therapy (ERT) resulted in amelioration of hyperferritinemia: 707 +/- 898 ng/ml vs. 301 +/- 310 ng/ml (P = 0.001), transferrin saturation remained normal. Three patients were suspected of clinical iron overload, confirmed on liver biopsy. Iron accumulation was variably noted in hepatocytes and Kupffer cells. There is a high prevalence of hyperferritinemia in Type 1 Gaucher disease that is associated with indicators of disease severity, reversed by ERT and is not related to HFE mutations.

Gaucher disease: a systematic review and meta-analysis of bone complications and their response to treatment

Type 1 Gaucher disease (GD1) is an inherited lysosomal storage disease, which is often managed by enzyme replacement therapy (ERT). The bone response to ERT is usually slower than visceral and hematological responses. There is uncertainty as to whether an increase in the dosage of ERT has a beneficial effect. The aim of our study was to determine whether or not there is sufficient evidence to make a definitive statement about the effects of ERT and substrate reduction therapy (SRT) on bone marrow infiltration and bone mineral density (BMD) in GD1. We conducted a systematic review of all studies examining the effects of ERT and SRT on bony complications of GD1 published before July 2008. The studies were identified by a computerized search with use of Medline, Embase, The Cochrane Database of Systematic Reviews, The Cochrane Central Register of Controlled Trials (CCTR), and bibliographies of papers subsequently retrieved from the search. Three hundred studies were grouped according to whether they deal with the natural history of GD1 or therapeutic issues, and 17 studies were included in the review. The results from our systematic review suggest that further investigations, such as better analysis of the Gaucher Registry, are needed on the effects of ERT and SRT on bony complications of GD1. Studies on the effects of the newly identified velaglucerase and the plant-derived glucocerebrosidase on bony complications of GD1 are also needed.

Effects of imiglucerase treatment on traumatic fracture and bone and blood abnormalities in a patient with previously untreated type 1 gaucher disease

OBJECTIVE

This letter reports on the effect of enzyme replacement therapy with imiglucerase on bone healing and bone and blood abnormalities in a woman with previously untreated type 1 Gaucher disease (GD).

METHODS

The 49-year-old patient had been diagnosed with GD at the age of 28 years and had previously undergone splenectomy. She presented with pseudarthrosis 14 months after sustaining a traumatic fracture of the tibia and fibula. Therapy was begun with imiglucerase 60 U/kg q2wk. The effects of treatment on bone healing were monitored radiographically, and effects on blood and bone marrow biology were monitored by hemograms, myelograms, and hematopoietic and mesenchymal clonogenic assays.

RESULTS

Objective bone healing was observed starting in the third month of imiglucerase treatment. Blood abnormalities normalized and bone marrow parameters improved over the first 9 months, including a decrease in Gaucher cells, an increase in bone marrow CD34+ cell cloning efficiency, and the appearance of mesenchymal progenitors.

CONCLUSION

This research letter reports the results of hematologic and bone evaluations during enzyme replacement therapy with imiglucerase in a woman with previously untreated type 1 GD who presented with a traumatic fracture.

The female Gaucher patient: the impact of enzyme replacement therapy around key reproductive events (menstruation, pregnancy and menopause)

BACKGROUND

The principal manifestations of type 1 Gaucher disease (GD) (increased risk of bleeding, anaemia, splenomegaly, hepatomegaly and bone disease) are likely to affect females during reproductive events such as menarche and menstruation; fertility, pregnancy, parity, delivery and lactation; and menopause. In order to determine the optimal management of female Gaucher patients based on available data, we examine reproductive events and GD in untreated and alglucerase and/or imiglucerase-treated females.

METHODS

A panel of international clinicians experienced in the management of GD reviewed and presented evidence from peer-reviewed literature, a pharmacovigilance database on imiglucerase, and their own clinical experience to support discussions and recommendations. Nine panel members completed a 130-item-questionnaire on the outcomes of the management of female patients in their clinical practice. Results, covering menarche (137 females), menstruation (261 reports), fertility (295 females), pregnancy (416 pregnancies in 247 women) and menopause (45 women) were analysed. Data from a recent Canadian survey on 50 patients with 39 pregnancies, the imiglucerase pharmacovigilance database (100 pregnancies), and relevant literature (56 items covering 398 pregnancies in 205 women) were also reviewed.

KEY RESULTS

Menarche: May be delayed in girls with GD. Menorrhagia: Appears to be more common in GD than in the non-Gaucher population and may be ameliorated by alglucerase and/or imiglucerase treatment (menorrhagia in 67/133 (50.4%) untreated females compared with 37/128 (28.9%) treated; Mann-Whitney U test: p=0.001). Fertility: There is no evidence of decreased fertility in GD. Pregnancy: Pregnancy in GD may be complicated by haematological disease, organomegaly and bone involvement. GD diagnosis occurs frequently during pregnancy. Questionnaire results demonstrate: a reduced risk of spontaneous abortion in women treated with alglucerase and/or imiglucerase (untreated: 26/189 (13.8%); treated 1/58 (1.7%) chi(2)p=0.010); reduced risk of Gaucher-related complications during delivery (untreated 43/109 (39.4%); treated 3/46 (6.5%) chi(2)p<0.0005): and a reduced risk of Gaucher-related complications during the post partum period (untreated 15/71 (21.1%); treated 3/43 (7%) chi(2)p=0.014). There is no evidence to date of any untoward effect of alglucerase and/or imiglucerase on the fetus, or on infants breast fed by mothers receiving alglucerase and/or imiglucerase. Menopause: The impact of GD on menopause requires further study especially in relation to bone pathology.

CONCLUSIONS

On the basis of this review, GD may have an impact on reproductive events in affected women. Enzyme therapy may have benefits in reducing menorrhagia, spontaneous abortions and complications associated with delivery and the postpartum period.

Atteintes ostéoarticulaires de la maladie de Gaucher chez l'adulte: de la physiopathologie au traitement

Gaucher disease frequently has severe osteoarticular manifestations that may be disabling. Ischemic phenomena cause the most serious complications and lead to irreversible lesions. Aseptic osteonecrosis of the hip is the most disabling complication; it causes intense early bone pain and often joint collapse and secondary osteoarthritis in young adults. Localized or systemic bone fragility explains osteopenia, osteoporosis, and fractures (vertebral collapse with irreversible kyphosis causing chronic morbidity). Although no double-blind randomized studies have assessed the bone effects of enzyme replacement therapy, it has been shown effective in reducing bone pain in about half of all treatment-naive patients within 1 to 2 years and in improving bone mineral density after 3 years. In open-label trials, substrate reduction therapy (miglustat) reduced both bone pain and bone marrow infiltration. Specific treatment for bone fragility, with bisphosphonates for example, should be considered after rigorous individualized evaluation and assessment of other risk factors.

Recommendations for the management of the haematological and onco-haematological aspects of Gaucher disease

Current knowledge of the haematological and onco-haematological complications of type 1 Gaucher disease has been reviewed with the aim of identifying best clinical practice for treatment and disease management. It was concluded that: (i) Awareness of typical patterns of cytopenia can help clinicians distinguish haematological co-morbidities. (ii) Red blood cell studies and complete iron metabolism evaluation at baseline are recommended. (iii) Haemoglobin levels defining anaemia should be raised and used in Gaucher disease treatment and monitoring. (iv) Surgeons should be aware of potential bleeding complications during surgery in Gaucher patients. The higher incidence of multiple myeloma in Gaucher disease suggests that Gaucher patients should have their immunoglobulin profile determined at diagnosis and monitored every 2 years (patients <50 years) or every year (patients >50 years). If monoclonal gammopathy of undetermined significance (MGUS) is found, general MGUS guidelines should be followed. Future studies should focus on the utility of early treatment to prevent immunoglobulin abnormalities and multiple myeloma.

Evidence-based recommendations for monitoring bone disease and the response to enzyme replacement therapy in Gaucher patients

BACKGROUND

Bone disease is a serious complication of Gaucher disease. Untreated, it can result in pain, permanent bone damage and disability. Enzyme replacement therapy reverses many of the clinical signs of Gaucher bone disease but early assessment and treatment, and regular monitoring, are essential in optimising outcomes.

SCOPE

In September 2005, a group of European experts met to review current knowledge and identify best practice and unmet needs in the monitoring of Gaucher bone disease and the response to enzyme replacement therapy.

METHODS

Medline searches of peer-reviewed literature (no date restrictions) were conducted and supplemented by additional information considered relevant by panellists to furthering discussions.

FINDINGS AND CONCLUSIONS

The group's recommendations included: currently used biochemical bone markers are not clinically practical or reliable; plain X-rays should not be the sole method of assessing bone disease; MRI is the most sensitive method for monitoring bone marrow infiltration by Gaucher cells; semi-quantitative methods for assessing bone marrow infiltration in routine clinical practice should use readily available technology, include an assessment of Gaucher cell infiltration in the lumbar spine and femur, and be validated for inter-rater reliability and in comparison to other methods; a multidisciplinary approach is required for the treatment of Gaucher patients; all Gaucher patients should receive a comprehensive initial radiologic evaluation for bone disease and ongoing radiological monitoring at least once every 2 years.

Enzyme replacement therapy and bony changes in Egyptian paediatric Gaucher disease patients

BACKGROUND

In Gaucher disease, the infiltration of the bone marrow by glucocerebroside-laden macrophages (Gaucher cells) triggers a diverse pattern of skeletal disease that results in crippling complications. Reliable ascertainment of the severity and pattern of skeletal disease is essential to determine disease status and the response to enzyme replacement therapy (ERT). Although there is ample documentation of reversal of haematological and visceral disease by ERT, there is a paucity of data on skeletal response to ERT in children.

AIM

To delineate the pattern of bone disease in children with Gaucher disease in Egypt and to evaluate its response to ERT.

METHOD

Twenty-two children with Gaucher disease were treated with ERT. Phenotyping by clinical, laboratory and radiological criteria was performed at baseline and following 11.2 +/- 4 months of ERT. Genotyping for glucocerebrosidase (GBA) mutations was performed by gene sequencing, and genotype-phenotype correlations were performed.Results. Two-thirds of the patients were from consanguineous pedigrees and 14/22 patients were homozygous or compound heterozygous for L444P and D409H mutations. Bone involvement was detected by plain radiology in 11 children (50%) and in 16 (73%) by magnetic resonance imaging (MRI). There was no correlation of severity of bone involvement and GBA genotype. ERT ameliorated bone disease: 10 of the 11 children with abnormal radiographic findings at baseline showed improvement in skeletal lesions; while 9/16 showed improvement of marrow disease by MRI. Radiographic sensitivity and specificity were 62% and 82% compared to MRI for detection of bone involvement in this patient population. At baseline, bone pain was present in 5 patients and ERT resulted in complete symptomatic remission in all of them. ERT was associated with significant improvement in growth parameters and amelioration of haematological and visceral involvement.

CONCLUSION

Symptomatic and radiological skeletal disease is common in children with Gaucher disease in Egypt. MRI is the most accurate technique for detecting early skeletal involvement. There was no correlation between severity of skeletal involvement and GBA genotype. ERT was effective in ameliorating radiological manifestations of skeletal disease and achieving complete remission of bone pain.

Improved intracellular delivery of glucocerebrosidase mediated by the HIV-1 TAT protein transduction domain

Enzyme replacement therapy (ERT) for Gaucher disease designed to target glucocerebrosidase (GC) to macrophages via mannose-specific endocytosis is very effective in reversing hepatosplenomegaly, and normalizing hematologic parameters but is less effective in improving bone and lung involvement and ineffective in brain. Recombinant GCs containing an in-frame fusion to the HIV-1 trans-activator protein transduction domain (TAT) were expressed in eukaryotic cells in order to obtain active, normally glycosylated GC fusion proteins for enzyme uptake studies. Despite the absence of mannose-specific endocytic receptors on the plasma membranes of various fibroblasts, the recombinant GCs with C-terminal TAT fusions were readily internalized by these cells. Immunofluorescent confocal microscopy demonstrated the recombinant TAT-fusion proteins with a mixed endosomal and lysosomal localization. Thus, TAT-modified GCs represent a novel strategy for a new generation of therapeutic enzymes for ERT for Gaucher disease.

Survey of hematological aspects of Gaucher disease

Hematologists have classically been the treating physicians of patients with Gaucher disease, and today, despite both specific and symptomatic therapeutic advances, they remain at the forefront of specialists to whom patients with Gaucher disease present. It is therefore appropriate to review that has changed and what has remained the same in hematological signs and symptoms of the disease in the decade and a half since therapy has become available.

Therapeutic goals in the treatment of Gaucher disease

Gaucher disease, the most common lysosomal storage disorder, is a heterogeneous multisystem condition. Patients with non-neuronopathic (type 1) Gaucher disease may suffer from hepatomegaly, splenomegaly, thrombocytopenia, bleeding tendencies, anemia, hypermetabolism, skeletal pathology, growth retardation, pulmonary disease, and decreased quality of life. Enzyme replacement therapy (ERT) with mannose-terminated glucocerebrosidase reverses or ameliorates many of the manifestations of type 1 Gaucher disease. However, the variable disease pattern and severity, and the uncertain manner of progression, render the decision to initiate ERT difficult. Thus, implementation of treatment and evaluation of the therapeutic response must be tailored to the individual patient. To obtain an evidence-based consensus on contemporary therapeutic goals, an international panel of physicians with extensive clinical experience in Gaucher disease met to review the extant literature on its treatment. The panel adopted an integrated system-based approach to arrive at a comprehensive guide to individualized management. Here we establish goals of treatment in Gaucher disease and propose a comprehensive schedule of monitoring of all relevant aspects to confirm the achievement, maintenance, and continuity of the therapeutic response.

Musculoskeletal complications associated with lysosomal storage disorders: Gaucher disease and Hurler-Scheie syndrome (mucopolysaccharidosis type I)

PURPOSE OF REVIEW

Enzyme therapy for lysosomal storage disorders directed at correcting the underlying cause of disease represents the most significant recent advance in patient management. This review focuses on two disease groups: glycosphingolipidoses and mucopolysaccharidoses. Specifically, Gaucher disease and Hurler-Scheie syndrome have been selected as the prototypical disorder for each respective class.

RECENT FINDINGS

Musculoskeletal complications are encountered in several of the lysosomal storage disorders and often represent a major source of extraneurologic morbidity, particularly in the subacute or chronic variants. Enzyme therapy has led to improvements in physical and functional well-being. However, bone involvement remains a recalcitrant feature, especially among patients with established disease before institution of therapy.

SUMMARY

Early diagnosis and appropriate timely intervention are critical in achieving the best therapeutic results. A better understanding of the fundamental mechanisms of bone pathology may enable the identification of complementary approaches (eg, the use of bisphosphonates for severe osteopenia) for optimized outcomes. Symptomatic care and rigorous physical and occupational therapy remain critical components of a comprehensive management approach.

Correlation of surrogate markers of Gaucher disease. Implications for long-term follow up of enzyme replacement therapy

BACKGROUND

The excessive storage of cellular debris in the lysosomal storage disorders triggers a variety of cellular responses. Some of these responses are maladaptative and result in the pathology of these diseases. To some extent, cellular responses are specific to the stored material, which influences the pathophysiology of the disease and results in some of its characteristic features.

METHODS

A large body of data has been collected for three biochemical (surrogate) markers of Gaucher Disease: angiotensin converting enzyme (ACE), tartrate-resistant acid phosphatase (TRAP) and chitotriosidase (CHITO) using currently available enzyme analysis. Follow up data was gathered in a group of 18 patients.

RESULTS

The three markers are correlated between each other and are useful indicators of the disease progress and its response to enzyme replacement therapy (ERT). Retrospective analysis of clinical records and comparison of chitotriosidase values with the baseline Severity Score Index (SSI) allowed prediction of the response patterns for this marker when long-term ERT (>24 months) was evaluated.

CONCLUSIONS

The less severely affected patients are more likely to normalize their chitotriosidase activities after long term ERT.

The role of the iminosugar N-butyldeoxynojirimycin (miglustat) in the management of type I (non-neuronopathic) Gaucher disease: a position statement

N-Butyldeoxynojirimycin (NB-DNJ, miglustat 'Zavesca') is an orally active iminosugar which inhibits the biosynthesis of macromolecular substrates that accumulate pathologically in glycosphingolipidoses. Clinical trials of NB-DNJ in patients with Gaucher's disease demonstrate the therapeutic potential of such substrate inhibitors in the glycolipid storage disorders. However, macrophage-targetted enzyme replacement using intravenous mannose-terminated human glucocerebrosidase (imiglucerase, Cerezyme) is highly effective in ameliorating many of the manifestations of Gaucher's disease and is a treatment in widespread use. Given that imiglucerase and miglustat are now both licensed for the treatment of Gaucher's disease, there is a need to review their therapeutic status. Here the treatment of type 1 (non-neuronopathic) Gaucher disease is evaluated with particular reference to the emerging role of oral N-butyldeoxynojirimycin (miglustat) as a substrate-reducing agent. This position statement represents the consensus viewpoint of an independent international advisory council to the European Working Group on Gaucher Disease.

Enzyme therapy of gaucher disease: clinical and biochemical changes during production of and tolerization for neutralizing antibodies

The clinical impact of neutralizing antibodies directed against the therapeutic enzyme was investigated in patients with Gaucher disease. Two patients with Gaucher disease type 1 were followed for their clinical progression during antibody development and clinical changes during tolerization. Patient 1 developed neutralizing antibodies to imiglucerase (GCase) at the 10th month of enzyme therapy. Tolerization was achieved within a 42-month period with a short course of cyclophosphamide and then higher dose enzyme (60 IU/kg/week) alone. Patient 1 continues to improve up to 100 months of enzyme therapy despite the presence of low level in vitro neutralizing antibodies. Patient 2 developed neutralizing antibodies to GCase at the 29th month of enzyme therapy that correlated with clinical deterioration. Clinical stabilization has been observed with increased enzyme therapy (60 IU/kg/week) even in the presence of the neutralizing antibodies. Patient 2 is the first to develop neutralizing antibodies after 12 months of enzyme therapy. Plasma chitotriosidase activities were not well correlated with the clinical course in either patient. The presence of neutralizing antibodies should be suspected in Gaucher disease patients on enzyme therapy who experience diminished response or deterioration. The persistence of minimal amounts of in vitro neutralizing antibodies does not interfere with the therapeutic effectiveness. Chitotriosidase is not a sensitive marker for the severity of disease or disease progression.