Dominick Amato

Mount Sinai Hospital, Toronto, Toronto, Ontario, Canada

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Publications (37)178.53 Total impact

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    ABSTRACT: Gastrointestinal (GI) disturbances such as diarrhea and flatulence are the most frequent adverse effects associated with miglustat therapy in type 1 Gaucher disease (GD1) and Niemann-Pick disease type C (NP-C), and the most common recorded reason for stopping treatment during clinical trials and in clinical practice settings. Miglustat-related GI disturbances are thought to arise from the inhibition of intestinal disaccharidases, mainly sucrase isomaltase. We report the effects of a co-administered dietary probiotic, S. boulardii, on the GI tolerability of miglustat in healthy adult subjects. In a double-blind, placebo-controlled, two-period, two-treatment cross-over trial, healthy adult male and female subjects were randomly allocated to treatment sequences, A-B and B-A (treatment A - miglustat 100 mg t.i.d. + placebo; treatment B - miglustat 100 mg t.i.d. + S. boulardii [500 mg, b.i.d.]). GI tolerability data were collected in patient diaries. The primary endpoint was the total number of 'diarrhea days' (≥3 loose stools within a 24-h period meeting Bristol Stool Scores [BSS] 6-7) based on WHO criteria. Secondary endpoints comprised numerous other diarrhea and GI tolerability indices. Twenty-one subjects received randomized therapy in each treatment sequence (total N = 42), and overall, 37 (88 %) subjects completed the study. The total number of diarrhea days was <1.5 for both treatment sequences, and approximately 60 % of subjects did not experience diarrhea during either treatment period. The mean (SD) number of diarrhea days was lower with miglustat + S. boulardii (0.8 [2.4] days) than with miglustat + placebo (1.3 [2.4] days), but the paired treatment difference was not statistically significant (-0.5 [2.4] days; p = 0.159). However, a significant treatment difference (-0.7 [1.9]; p < 0.05) was identified after post hoc exclusion of a clear outlier who had a very high number of diarrhea days (n = 13) and inconsistent GI tolerability reporting. The incidence of the GI AEs was higher with miglustat + placebo (82 %) than with miglustat + S. boulardii (73 %). There were no between-treatment differences in miglustat pharmacokinetics. Although the primary endpoint was not met, the results of the post-hoc analysis suggest that co-administration of miglustat with S. boulardii might improve GI tolerability.
    Orphanet Journal of Rare Diseases 06/2015; 10(1):81. DOI:10.1186/s13023-015-0297-7 · 3.96 Impact Factor
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    ABSTRACT: GD1-DS3 is an integrated assessment of type 1 Gaucher disease (GD1) burden based on bone, hematologic and visceral domains. We investigated this disease severity scoring system (DS3) methodology for initial assessment, long-term follow-up and evaluation of treatment responses. We enrolled 133 treated adult GD1 patients. Baseline DS3 scores were calculated near the initial treatment date and patients stratified by severity as marked (DS3 6.00-19.00), moderate (DS3 3.00-5.99), mild (DS3 < 3.00). Follow-up scores were calculated annually. Minimal clinically important improvement (MCII), is defined as ΔDS3 of -3.1. Patient characteristics: N370S was the most common allele (118 patients had at least one), 52 were N370S/N370S (48/52 were Ashkenazi Jews), N370S/L444P was the most common genotype among non-Jews. Median age of treatment: 45 years; median follow-up: 14 years. Baseline DS3 scores: Patients with marked disease (N = 58; median 7.84) were least likely to be N370S homozygous (19%) and most likely to have had splenectomy (53%), early age at diagnosis (median 18 years) and major pre-treatment bone pathology (76%). Among patients with moderate disease (N = 53; median 4.33), 49% were N370S/N370S, 15.1% had splenectomy and 17% had major bone disease. Median age at diagnosis: 32 years. No patient with mild disease (N = 22; median 2.4) had splenectomy or major skeletal disease. Median age at diagnosis: 40 years. 68% were N370S homozygous. Response to treatment: Health-state transitions occurred primarily during the early treatment years. At Year 5, among 48 evaluable patients with marked baseline disease, eight were unchanged in severity status whereas 40 had MCII of varying degrees with 11 scored as mild. Among 42 evaluable moderate patients, none worsened, 16 remained moderate and 26 improved to mild. Among 16 evaluable mild patients, 14 remained so and 2 had DS3 scores in the low moderate range. DS3 is effective for assessing disease burden in GD1 and for monitoring response. ERT was associated with MCII in DS3 scores in patients with high severity. Nevertheless, despite better DS3 scores with treatment, GD1 patients especially those with splenectomy and pre-treatment bone pathology, continued to have bone complications.
    Orphanet Journal of Rare Diseases 05/2015; 10(1):64. DOI:10.1186/s13023-015-0280-3 · 3.96 Impact Factor
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    ABSTRACT: Gaucher disease type 1 is characterized by hepatosplenomegaly, anemia, thrombocytopenia, and skeletal disease. A safe, effective oral therapy is needed. To determine whether eliglustat, a novel oral substrate reduction therapy, safely reverses clinical manifestations in untreated adults with Gaucher disease type 1. 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. 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. 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. 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. 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. Identifier: NCT00891202.
    JAMA The Journal of the American Medical Association 02/2015; 313(7):695-706. DOI:10.1001/jama.2015.459 · 30.39 Impact Factor
  • Molecular Genetics and Metabolism 02/2015; 114(2):S81-S82. DOI:10.1016/j.ymgme.2014.12.179 · 2.83 Impact Factor
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    ABSTRACT: Taliglucerase alfa is a β-glucosidase enzyme replacement therapy (ERT) approved in the US and other countries for the treatment of Gaucher disease (GD) in adults and is approved in pediatric and adult patients in Australia and Canada. It is the first approved plant cell-expressed recombinant human protein. A Phase 3, multicenter, open-label, 9-month study assessed safety and efficacy of switching to taliglucerase alfa in adult and pediatric patients with GD treated with imiglucerase for at least the previous 2 years. Patients with stable disease were offered taliglucerase alfa treatment using the same dose (9–60 U/kg body weight) and regimen of administration (every 2 weeks) as imiglucerase. This report summarizes results from 26 adult and 5 pediatric patients who participated in the trial. Disease parameters (spleen and liver volumes, hemoglobin concentration, platelet count, and biomarker levels) remained stable through 9 months of treatment in adults and children following the switch from imiglucerase. All treatment-related adverse events were mild or moderate in severity and transient in nature. Exploratory parameters of linear growth and development showed positive outcomes in pediatric patients. These findings provide evidence of the efficacy and safety profile of taliglucerase alfa as an ERT for GD in patients previously treated with imiglucerase. This trial was registered at as # NCT00712348.
    Blood Cells Molecules and Diseases 12/2014; 53(4). DOI:10.1016/j.bcmd.2014.05.004 · 2.33 Impact Factor
  • Molecular Genetics and Metabolism 02/2014; 111(2):S30. DOI:10.1016/j.ymgme.2013.12.053 · 2.83 Impact Factor
  • Molecular Genetics and Metabolism 02/2014; 111(2):S112-S113. DOI:10.1016/j.ymgme.2013.12.281 · 2.83 Impact Factor
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    ABSTRACT: Gaucher disease is an autosomal recessive lysosomal storage disorder resulting from deficient glucocerebrosidase activity. There have been nearly 300 mutations described to date. Novel mutations can potentially provide insight into the biochemical basis of the disease. Two novel mutations are described in two Type 1 Gaucher patients with N370S compound heterozygosity; a point mutation that causes an amino acid substitution at cysteine residue 23 for tryptophan, and a second point mutation within the splicing element at the 3' end of intron 7. Both mutations were identified by PCR amplification and sequence analysis of patient glucocerebrosidase genomic DNA. Restriction fragment length polymorphism analysis was established for both novel mutations for efficient identification in future patients. Past literature suggests that mutations affecting cysteine residues involved in disulfide bridges, as well as mutations affecting splicing patterns of the glucocerebrosidase transcript, are detrimental to enzyme activity. However, compound heterozygosity with N370S, a mild mutation, will lead to a mild phenotype. The cases reported here support these past findings.
    Gene 01/2014; DOI:10.1016/j.gene.2014.01.015 · 2.08 Impact Factor
  • American Journal of Hematology 11/2013; 88(11). DOI:10.1002/ajh.23542 · 3.48 Impact Factor
  • Molecular Genetics and Metabolism 02/2013; 108(2):S66-S67. DOI:10.1016/j.ymgme.2012.11.171 · 2.83 Impact Factor
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    ABSTRACT: Previous studies have provided equivocal data on the use of miglustat as maintenance therapy in Gaucher disease type 1. We report findings from a clinical trial evaluating the effects of miglustat treatment in patients with stable type 1 Gaucher disease after enzyme therapy. Adult type 1 Gaucher disease patients stabilized during at least 3 years of previous enzyme therapy were included in this 2-year, prospective, open-label non-inferiority study. The primary endpoint was percent change from baseline in liver volume. Secondary endpoints included changes in spleen volume, hemoglobin concentration and platelet count. Forty-two patients were enrolled (mean±SD age, 45.1±12.7 years; previous enzyme therapy duration 9.5±4.0 years). Median (range) exposure to miglustat 100 mg t.i.d. was 658 (3–765) days. Twenty-one patients discontinued treatment prematurely; 13 due to adverse events, principally gastrointestinal. The upper 95% confidence limit of mean percent change in liver volume from baseline to end of treatment was below the non-inferiority margin of 10% (–1.1%; 95%CI −6.0, 3.9%). Mean (95%CI) changes in spleen volume, hemoglobin concentration and platelet count were 102 (24,180) mL, –0.95 (−1.38, –0.53) g/dL and −44.1 (–57.6, –30.7) ×109/L, respectively. The primary efficacy endpoint was met; overall there was no change in liver volume during 24 months of miglustat therapy. Several patients showed a gradual deterioration in some disease manifestations, suggesting that miglustat could maintain clinical stability, but not in all patients. Miglustat demonstrated a predictable profile of safety and tolerability that was consistent with that reported in previous clinical trials and experience in clinical practice. Trial registration identifier NCT00319046
    Orphanet Journal of Rare Diseases 12/2012; 7(1):102. DOI:10.1186/1750-1172-7-102 · 3.96 Impact Factor
  • Blood 05/2012; 119(19):4577-4577. DOI:10.1182/blood-2012-01-408054 · 10.43 Impact Factor
  • Molecular Genetics and Metabolism 02/2012; 105(2):S68. DOI:10.1016/j.ymgme.2011.11.186 · 2.83 Impact Factor
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    ABSTRACT: Taliglucerase alfa (Protalix Biotherapeutics, Carmiel, Israel) is a novel plant cell-derived recombinant human β-glucocerebrosidase for Gaucher disease. A phase 3, double-blind, randomized, parallel-group, comparison-dose (30 vs 60 U/kg body weight/infusion) multinational clinical trial was undertaken. Institutional review board approvals were received. A 9-month, 20-infusion trial used inclusion/exclusion criteria in treatment-naive adult patients with splenomegaly and thrombocytopenia. Safety end points were drug-related adverse events: Ab formation and hypersensitivity reactions. Primary efficacy end point was reduction in splenic volume measured by magnetic resonance imaging. Secondary end points were: changes in hemoglobin, hepatic volume, and platelet counts. Exploratory parameters included biomarkers and bone imaging. Twenty-nine patients (11 centers) completed the protocol. There were no serious adverse events; drug-related adverse events were mild/moderate and transient. Two patients (6%) developed non-neutralizing IgG Abs; 2 other patients (6%) developed hypersensitivity reactions. Statistically significant spleen reduction was achieved at 9 months: 26.9% (95% confidence interval [CI]: -31.9, -21.8) in the 30-unit dose group and 38.0% (95% CI: -43.4, -32.8) in the 60-unit dose group (both P < .0001); and in all secondary efficacy end point measures, except platelet counts at the lower dose. These results support safety and efficacy of taliglucerase alfa for Gaucher disease.
    Blood 09/2011; 118(22):5767-73. DOI:10.1182/blood-2011-07-366955 · 10.43 Impact Factor
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    Fenglin Cao · Dominick Amato · Chen Wang
    American Journal of Hematology 09/2011; 86(9):782. DOI:10.1002/ajh.21970 · 3.48 Impact Factor
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    Samantha Kimball · Francis Choy · Agnes Zay · Dominick Amato
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    ABSTRACT: Gaucher disease (GD) is characterized by reduced activity of glucocerebrosidase leading to complications in the reticuloendothelial system. N396T, a rarer mutation of the glucocerebrosidase gene, has been encountered in Portuguese populations and has generally been associated with milder phenotypes. This report presents brief histories of two Portuguese sisters, both with homozygous N396T mutations. These patients are phenotypically very different despite the fact that in both patients residual enzyme activity is very low. The case of patient 1 is complicated by comorbid diabetes mellitus and human immunodeficiency virus (HIV) infection. Enzyme replacement therapy (ERT) improved this patient's clinical picture sufficiently to enable antiretroviral treatment to proceed for the HIV. This report demonstrates the poor correlation of clinical GD with genotype as well as with residual enzyme activity. It further illustrates how treatment of the underlying GD with ERT improved symptoms allowing for antiretroviral therapy thereby improving both the GD and HIV.
    International Medical Case Reports Journal 03/2011; 4:17-20. DOI:10.2147/IMCRJ.S17144
  • Molecular Genetics and Metabolism 02/2011; 102(2). DOI:10.1016/j.ymgme.2010.11.113 · 2.83 Impact Factor
  • Siavash Piran · Dominick Amato
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    ABSTRACT: 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.
    Journal of Inherited Metabolic Disease 03/2010; 33(3):271-9. DOI:10.1007/s10545-010-9071-0 · 4.14 Impact Factor
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    ABSTRACT: Total hip replacement in patients with Gaucher's disease with symptomatic osteonecrosis of the femoral head is controversial because of the high early failure rates. We describe four patients who had an uncemented total hip replacement following enzyme replacement therapy for a median of two years and one month (1 to 9.8 years) prior to surgery, and who remained on treatment. At operation, the bone had a normal appearance and consistency. Histopathological examination showed that, compared with previous biopsies of untreated Gaucher's disease, the Gaucher cell infiltrate had decreased progressively with therapy, being replaced by normal adipose tissue. The surfaces of viable bone beyond the osteonecrotic areas showed osteoblasts, indicating remodelling. In one case acetabular revision was carried out after 11 years and eight months. The three remaining patients had a mean follow-up of six years and four months (3.3 to 12 years). We recommend initiating enzyme replacement therapy at least one to two years prior to total hip replacement to facilitate bone remodelling and to allow implantation of uncemented components in these young patients.
    The Bone & Joint Journal 12/2009; 91(12):1623-7. DOI:10.1302/0301-620X.91B12.22515 · 2.80 Impact Factor
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    ABSTRACT: Gaucher disease (GD) is a lysosomal storage disorder characterized by anemia and thrombocytopenia, hepatosplenomegaly, and skeletal involvement. The management of Gaucher disease was improved by the development of enzyme replacement therapy (ERT). However, the bone response to ERT is generally slower compared to other clinical manifestations. Some have recommended the early use of ERT to prevent the development of severe skeletal complications. Because we have access to over 30 untreated patients in Ontario, we questioned the extent to which complications progress in severity over a long period of time. We examined retrospectively the natural history of GD and the extent of skeletal manifestations in 22 untreated type 1 GD adult patients (mean age, 49+/-3.3; range, 20-81 years). The patients were followed for a median of 9.5 years (range, 3-16 years). Hemoglobin (Hb) concentration did not significantly change over time (mean baseline concentration of 12.8+/-0.27 g/dL vs. mean recent concentration of 12.6+/-0.37 g/dL, p=0.65). Mean platelet count also remained relatively stable over time (mean baseline count of 138+/-13x10(9)/L vs. mean recent count of 138.5+/-18x10(9)/L, p=0.98). Mean ferritin and ACE concentrations were elevated and were stable over time. Liver volumes decreased over time (mean baseline liver volume of 1.2xnormal (N) vs. mean recent volume of 1.06xN, p=0.27) and 6 of 22 (27%) patients had moderate hepatomegaly (liver volume, 1.25-2.5xN). Spleen volumes remained stable over time (mean baseline spleen volume of 6.6xN vs. mean recent volume of 5.2xN, p=0.5). None of the changes was statistically significant. Four of 20 (20%) patients had moderate splenomegaly (spleen volume, 5-15xN), 2 of 20 (10%) had marked splenomegaly (spleen volume, >or=15xN), and 2 of 22 (9%) had had splenectomy. The most common skeletal manifestations were infiltration of the bone marrow in 16 of 22 (73%) patients followed by osteopenia in 15 of 22 (68%), Erlenmeyer flask deformity in 13 of 22 (59%), and infarctions in 6 of 22 (27%) patients. We observed that bone disease remained relatively stable over time in most patients, although three patients developed new infarcts over time, one developed an avascular necrosis (AVN), and four had an increase in the degree of osteopenia. Although GD and its skeletal complications progress in severity in some patients, our results suggest that GD complications, including bony disease, may stabilize over time. Therefore, early use of ERT may not be necessary in all type 1 GD patients.
    Blood Cells Molecules and Diseases 09/2009; 43(3):289-93. DOI:10.1016/j.bcmd.2009.08.002 · 2.33 Impact Factor

Publication Stats

354 Citations
178.53 Total Impact Points


  • 2007–2015
    • Mount Sinai Hospital, Toronto
      • Department of Pathology and Laboratory Medicine
      Toronto, Ontario, Canada
  • 2013–2014
    • Sinai Hospital
      Mount Sinai, New York, United States
  • 2001–2013
    • University of Toronto
      • • Mount Sinai Hospital
      • • Department of Medicine
      • • Hospital for Sick Children
      • • Department of Laboratory Medicine and Pathobiology
      Toronto, Ontario, Canada
  • 2000
    • The King's College
      Charlotte, North Carolina, United States