Hadhami Ben Turkia

Effect of Oral Eliglustat on Splenomegaly in Patients With Gaucher Disease Type 1 The ENGAGE Randomized Clinical Trial

IMPORTANCE Gaucher disease type 1 is characterized by hepatosplenomegaly, anemia, thrombocytopenia, and skeletal disease. A safe, effective oral therapy is needed. OBJECTIVE To determine whether eliglustat, a novel oral substrate reduction therapy, safely reverses clinical manifestations in untreated adults with Gaucher disease type 1. DESIGN, SETTING, AND PARTICIPANTS Phase 3, randomized, double-blind, placebo-controlled trial conducted at 18 sites in 12 countries from November 2009 to July 2012 among eligible patients with splenomegaly plus thrombocytopenia and/or anemia. Of 72 patients screened, 40 were enrolled. INTERVENTIONS Patients were stratified by spleen volume and randomized 1:1 to receive eliglustat (50 or 100 mg twice daily; n = 20) or placebo (n = 20) for 9 months. MAIN OUTCOMES AND MEASURES The primary efficacy end point was percentage change in spleen volume in multiples of normal from baseline to 9 months; secondary efficacy end points were change in hemoglobin level and percentage changes in liver volume and platelet count. RESULTS All patients had baseline splenomegaly and thrombocytopenia (mostly moderate or severe), most had mild or moderate hepatomegaly, and 20% had mild anemia. Least-square mean spleen volume decreased by 27.77% (95% CI, -32.57% to -22.97%) in the eliglustat group (from 13.89 to 10.17 multiples of normal) vs an increase of 2.26% (95% CI, -2.54% to 7.06%) in the placebo group (from 12.50 to 12.84 multiples of normal) for an absolute treatment difference of -30.03% (95% CI, -36.82% to -23.24%; P < .001). For the secondary end points, the least-square mean absolute differences between groups all favored eliglustat, with a 1.22-g/dL increase in hemoglobin level (95% CI, 0.57-1.88 g/dL; P < .001), 6.64% decrease in liver volume (95% CI, -11.37% to -1.91%; P = .007), and 41.06% increase in platelet count (95% CI, 23.95%-58.17%; P < .001). No serious adverse events occurred. One patient in the eliglustat group withdrew (non-treatment related); 39 of the 40 patients transitioned to an open-label extension study. CONCLUSIONS AND RELEVANCE Among previously untreated adults with Gaucher disease type 1, treatment with eliglustat compared with placebo for 9 months resulted in significant improvements in spleen volume, hemoglobin level, liver volume, and platelet count. The clinical significance of these findings is uncertain, and more definitive conclusions about clinical efficacy and utility will require comparison with the standard treatment of enzyme replacement therapy as well as longer-term follow-up. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00891202.

Enzyme replacement therapy with velaglucerase alfa in Gaucher disease: Results from a randomized, double‐blind, multinational, Phase 3 study

Type 1 Gaucher disease (GD1), resulting from glucocerebrosidase deficiency, leads to splenomegaly, hepatomegaly, anemia, thrombocytopenia, and bone involvement. Current standard treatment is enzyme replacement therapy. Velaglucerase alfa is an enzyme replacement product for GD1, with the same amino acid sequence as naturally occurring human glucocerebrosidase. This multinational, Phase 3 trial evaluated the efficacy and safety of two doses of velaglucerase alfa in 25 treatment‐naïve, anemic patients with GD1 (4–62 years of age), randomized to intravenous velaglucerase alfa 60 U/kg (n=12) or 45 U/kg body weight (n=13) every other week for 12 months. The primary endpoint was change from baseline in hemoglobin concentration in the 60 U/kg arm. At 12 months, mean hemoglobin concentrations increased from baseline [60 U/kg: +23.3%; +2.43 g/dL (P<0.001); 45 U/kg: +23.8%; +2.44 g/dL (P<0.001)], as did mean platelet counts [60 U/kg: +65.9%; +50.9 × 109/L (P=0.002); 45 U/kg: +66.4%; +40.9 × 109/L(P=0.01)]. Mean splenic volume decreased from baseline [60 U/kg: −50.4%, from 14.0 to 5.8 multiples of normal (MN) (P=0.003); 45 U/kg: −39.9%, from 14.5 to 9.5 MN (P=0.009)]. No drug‐related serious adverse events or withdrawals were observed. One patient developed antibodies. Velaglucerase alfa was generally well tolerated and effective for adults and children with GD1 in this study. All disease‐specific parameters measured demonstrated clinically meaningful improvements after 12 months. Am. J. Hematol. 88:166–171, 2013.

Velaglucerase alfa enzyme replacement therapy compared with imiglucerase in patients with Gaucher disease

Enzyme replacement therapy for Gaucher disease (GD) has been available since 1991. This study compared the efficacy and safety of velaglucerase alfa with imiglucerase, the previous standard of care. A 9‐month, global, randomized, double‐blind, non‐inferiority study compared velaglucerase alfa with imiglucerase (60 U/kg every other week) in treatment‐naïve patients aged 3–73 years with anemia and either thrombocytopenia or organomegaly. The primary endpoint was the difference between groups in mean change from baseline to 9 months in hemoglobin concentration. 35 patients were randomized: 34 received study drug (intent‐to‐treat: 17 per arm), 20 were splenectomized. Baseline characteristics were similar in the two groups. The per‐protocol population included 15 patients per arm. The mean treatment difference for hemoglobin concentration from baseline to 9 months (velaglucerase alfa minus imiglucerase) was 0.14 and 0.16 g/dL in the intent‐to‐treat and per‐protocol populations, respectively. The lower bound of the 97.5% one‐sided confidence interval in both populations lay within the pre‐defined non‐inferiority margin of −1.0 g/dL, confirming that velaglucerase alfa is non‐inferior to imiglucerase. There were no statistically significant differences in the secondary endpoints. Most adverse events were mild to moderate. No patient receiving velaglucerase alfa developed antibodies to either drug, whereas four patients (23.5%) receiving imiglucerase developed IgG antibodies to imiglucerase, which were cross‐reactive with velaglucerase alfa in one patient. This study demonstrates the efficacy and safety of velaglucerase alfa compared with imiglucerase in adult and pediatric patients with GD clinically characterized as Type 1. Differences in immunogenicity were also observed. Am. J. Hematol. 88:179–184, 2013.

Mucopolysaccharidosis type I: molecular characteristics of two novel alpha-L-iduronidase mutations in Tunisian patients.

BackgroundMucopolysaccharidosis type I (MPS I) is an autosomal storage disease resulting from defective activity of the enzyme α-L-iduronidase (IDUA). This glycosidase is involved in the degradation of heparan sulfate and dermatan sulfate. MPS I has severe and milder phenotypic subtypes.Aim of study: This study was carried out on six newly collected MPS I patients recruited from many regions of Tunisia.Patients and methods: Mutational analysis of the IDUA gene in unrelated MPS I families was performed by sequencing the exons and intron-exon junctions of IDUA gene.ResultsTwo novel IDUA mutations, p.L530fs (1587_1588 insGC) in exon 11 and p.F177S in exon 5 and two previously reported mutations p.P533R and p.Y581X were detected. The patient in family 1 who has the Hurler phenotype was homozygous for the previously described nonsense mutation p.Y581X.The patient in family 2 who also has the Hurler phenotype was homozygous for the novel missense mutation p.F177S. The three patients in families 3, 5 and 6 were homozygous for the p.P533R mutation. The patient in family 4 was homozygous for the novel small insertion 1587_1588 insGC. In addition, eighteen known and one unknown IDUA polymorphisms were identified.ConclusionThe identification of these mutations should facilitate prenatal diagnosis and counseling for MPS I in Tunisia.BackgroundMucopolysaccharidosis type I (MPS I) is an autosomal recessive lysosomal storage disorder caused by the deficient activity of the enzyme of α-L-iduronidase (IDUA, EC 3.2.1.76). This glycosidase is involved in the degradation of heparan sulfate and dermatan sulfate. The clinical phenotype of MPS I ranges from the very severe in Hurler syndrome (MPS IH) to the relatively benign in Scheie syndrome (MPS IS), with an intermediate phenotype designated Hurler/Scheie (MPS IH/S) [1]. Isolation of complementary and genomic DNAs encoding human α -L- iduronidase [2, 3] have enable the identification of mutations underlying the enzyme defect and resulting in MPS I clinical phenotype. More than 100 mutations have been reported in patients with the MPS I subtypes (Human Gene Mutation Database; http://www.hgmd.org). High prevalence of the common mutations p.W402X and p.Q70X has been described; both of them in the severe clinical forms [4, 5]. A high prevalence of common mutation p.P533R has also been described in MPS I patients with various phenotypes [5, 6]. In addition, rare mutations including single base substitution, deletion, insertion and splicing site mutation have been identified [7], indicating a high degree of allelic heterogeneity in IDUA gene.Here, we described two novel IDUA mutations in MPS I Tunisian patients. These lesions were homoallelic in all the patients of the six families investigated as consanguineous marriages are still frequent in Tunisia [8].

Outcomes after 18 months of eliglustat therapy in treatment-naïve adults with Gaucher disease type 1: The phase 3 ENGAGE trial

Eliglustat, an oral substrate reduction therapy, is a first‐line treatment for adults with Gaucher disease type 1 (GD1) who are poor, intermediate, or extensive CYP2D6 metabolizers (>90% of patients). In the primary analysis of the Phase 3 ENGAGE trial (NCT00891202), eliglustat treatment for 9 months resulted in significant reductions in spleen and liver volumes and increases in hemoglobin concentration and platelet count compared with placebo. We report 18‐month outcomes of patients who entered the trial extension period, in which all patients received eliglustat. Of 40 trial patients, 39 entered the extension period, and 38 completed 18 months. Absolute values and percent change over time were determined for spleen and liver volume, hemoglobin concentration, platelet count, bone mineral density, bone marrow burden, and Gaucher disease biomarkers. For patients randomized to eliglustat in the double‐blind period, continuing treatment with eliglustat for 9 more months resulted in incremental improvement of all disease parameters. For patients randomized to placebo in the double‐blind period, eliglustat treatment during the 9‐month, open‐label period resulted in significant decrease of spleen and liver volumes and significant increase of hemoglobin and platelets, with a similar rate of change to patients who had received eliglustat in the double‐blind period. Eliglustat treatment was also associated with improvement in bone marrow burden score, bone mineral density, and established biomarkers of Gaucher disease, including reduction of the bioactive lipid, glucosylsphingosine. These findings underscore the efficacy of eliglustat in treatment‐naïve patients. Eliglustat was well‐tolerated, and there were no new safety concerns with longer‐term exposure.

Cause of death in patients with chronic visceral and chronic neurovisceral acid sphingomyelinase deficiency (Niemann-Pick disease type B and B variant): Literature review and report of new cases.

BACKGROUND Acid sphingomyelinase deficiency (ASMD), [Niemann-Pick Disease Types A and B (NPD A and B)], is an inherited metabolic disorder resulting from deficiency of the lysosomal enzyme acid sphingomyelinase. Accumulation of sphingomyelin in hepatocytes, reticuloendothelial cells, and in some cases neurons, results in a progressive multisystem disease that encompasses a broad clinical spectrum of neurological and visceral involvement, including: infantile neurovisceral ASMD (NPD A) that is uniformly fatal by 3years of age; chronic neurovisceral ASMD (intermediate NPD A/B; NPD B variant) that has later symptom onset and slower neurological and visceral disease progression; and chronic visceral ASMD (NPD B) that lacks neurological symptoms but has significant disease-related morbidities in multiple organ systems. The purpose of this study was to characterize disease-related morbidities and causes of death in patients with the chronic visceral and chronic neurovisceral forms of ASMD. METHODS Data for 85 patients who had died or received liver transplant were collected by treating physicians (n=27), or abstracted from previously published case studies (n=58). Ages at symptom onset, diagnosis, and death; cause of death; organ involvement, and morbidity were analyzed. RESULTS Common disease-related morbidities included splenomegaly (96.6%), hepatomegaly (91.4%), liver dysfunction (82.6%), and pulmonary disease (75.0%). The overall leading causes of death were respiratory failure and liver failure (27.7% each) irrespective of age. For patients with chronic neurovisceral ASMD (31.8%), progression of neurodegenerative disease was a leading cause of death along with respiratory disease (both 23.1%) and liver disease (19.2%). Patients with chronic neurovisceral disease died at younger ages than those with chronic visceral disease (median age at death 8 vs. 23.5years). CONCLUSIONS The analysis emphasizes that treatment goals for patients with chronic visceral and chronic neurovisceral ASMD should include reducing splenomegaly and improving liver function and respiratory status, with the ultimate goal of decreasing serious morbidity and mortality.

Hurler disease (mucopolysaccharidosis type IH): clinical features and consanguinity in Tunisian population.

Mucopolysaccharidosis type I (MPS I) was a group of rare autosomal recessive disorder caused by the deficiency of the lysosomal enzyme, alpha -L -iduronidase, and the resulting accumulation of undergraded dematan sulfate and heparan sulfate. MPS I patients have a wide range of clinical presentations, that makes it difficult to predict patient phenotype which is needed for genetic counseling and also impedes the selection and evaluation of patients undergoing therapy bone marrow transplantation.Aim of the studyconsanguinity rates have been determined among 14 families with mucopolysaccharidosis type I, seen in the pediatric departments of different geographic areas of Tunisia (Central and Southern areas) for the period August 2004 - August 2011 in order to investigate the relation between consanguinity and this disorder.Patients and methodsClinical and molecular analyses confirmed the diagnosis for MPS type I in the studied families.ResultsMost of the Tunisian MPS I patients have been identified at the homozygous status: p.P533R mutation (7 homozygous and one double heterozygous p.L578Q/p.P533R patients; 41.66% of all the investigated MPSI patients), p.F177S (1 homozygous patient; 5.55%), p.L530fs (1 patient; 5.55%), p.Y581X (2 patients; 11.11%), p.F602X (3 patients; 16.66%), p.R628X (1 patient; 5.55%). Another mutation: p.L578Q has been identified at the heterozygous status in the only double heterozygous p.L578Q/p.P533R case. Part of the mutations was the result of a founder effect. These described points are the consequences of the high rate of consanguinity.ConclusionThe high frequency of p.P533R mutation could be explained by the high degree of inbreeding. This is due to the richness of the genetic background of the studied population.A multidisciplinary approach is essential to develop adequate preventive program adapted to the social, cultural, and economic context.Virtual SlidesThe virtual slides for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1863141266606652

Gaucher disease in Tunisia: High frequency of the most common mutations

a Molecular Investigation of Genetic Orphan Diseases Research Unit, Institut Pasteur de Tunis, Tunisia b Inherited Metabolic Diseases Unit, Pediatric Department, La Rabta Hospital, Tunis, Tunisia c Child Neurological Diseases Unit; Faculty of Medicine, Tunis, Tunisia d Pediatric Department, Sahloul Hospital, Sousse, Tunisia e Neurobiology Genetic Department, Biology Molecular and Cellular Institute, Porto University, Portugal f Metabolic Genetic Laboratory, Medicine Faculty, Cochin, France

Treatment-naïve Gaucher disease patients achieve therapeutic goals and normalization with velaglucerase alfa by 4 years in phase 3 trials

Gaucher disease is an inherited metabolic disease characterized by β-glucocerebrosidase deficiency and commonly treated with enzyme replacement therapy (ERT). The efficacy of ERT with velaglucerase alfa was assessed based on the achievement of published therapeutic goals and the normalization of disease parameters in 39 treatment-naïve patients with type 1 Gaucher disease, 6 to 62years of age, enrolled in phase 3 clinical trials. After 4years of ERT, therapeutic goals for thrombocytopenia and splenomegaly had been achieved in 100% of patients; goals for anemia and hepatomegaly had been achieved in 95% and 94% of patients, respectively. Consistent with the goal for bone mineral density, lumbar spine bone density improved in 87% of patients ≥18years of age. At year 4, compared with clinical ranges for healthy individuals, 86% of patients with a low baseline hemoglobin concentration had normalized, 60% with a low baseline platelet count had normalized, 67% with baseline splenomegaly had normalized, 58% with hepatomegaly had normalized, and lumbar spine bone density had normalized in 53% of adults. The decade-old therapeutic goals do not reflect the potential for normalization of clinical parameters in ERT-treated patients. Goals consistent with normalization or near-normalization should be considered. ClinicalTrials.gov identifiers: NCT00430625, NCT00553631, NCT00635427.

Splicing defects in ABCD1 gene leading to both exon skipping and partial intron retention in X-linked adrenoleukodystrophy Tunisian patient

X-linked adrenoleukodystrophy (X-ALD) affects the nervous system white matter and adrenal cortex secondary to mutations in the ABCD1 gene that encodes a peroxisomal membrane protein: the adrenoleukodystrophy protein. The disease is characterized by high concentrations of very long-chain fatty acids in plasma, adrenal, testicular and nervous tissues. Various types of mutations have been identified in the ABCD1 gene: point mutations, insertions, and deletions. To date, more than 40 point mutations have been reported at the splice junctions of the ABCD1 gene; only few functional studies have been performed to explore these types of mutations. In this study, we have identified de novo splice site mutation c.1780+2T>G in ABCD1 gene in an X-ALD Tunisian patient. Sequencing analysis of cDNA showed a minor transcript lacking exon 7 and a major transcript with a partial intron 7 retention due to activation of a new intronic cryptic splice site. Both outcomes lead to frameshifts with premature stop codon generation in exon 8 and intron 7 respectively. To the best of our knowledge, the current study demonstrates that a single splicing mutation affects the ABCD1 transcripts and the ALDP protein function.