Dominick Amato

Pivotal trial with plant cell-expressed recombinant glucocerebrosidase, taliglucerase alfa, a novel enzyme replacement therapy for Gaucher disease

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.

Mutation analysis of patients with Hermansky-Pudlak syndrome: a frameshift hot spot in the HPS gene and apparent locus heterogeneity

Hermansky-Pudlak syndrome (HPS) is a rare, autosomal recessive disorder in which oculocutaneous albinism, bleeding, and lysosomal ceroid storage result from defects of multiple cytoplasmic organelles-melanosomes, platelet-dense granules, and lysosomes. As reported elsewhere, we mapped the human HPS gene to chromosome segment 10q23, positionally cloned the gene, and identified three pathologic mutations of the gene, in patients from Puerto Rico, Japan, and Europe. Here, we describe mutation analysis of 44 unrelated Puerto Rican and 24 unrelated non-Puerto Rican HPS patients. A 16-bp frameshift duplication, the result of an apparent founder effect, is nearly ubiquitous among Puerto Rican patients. A frameshift at codon 322 may be the most frequent HPS mutation in Europeans. We also describe six novel HPS mutations: a 5 splice-junction mutation of IVS5, three frameshifts, a nonsense mutation, and a one-codon in-frame deletion. These mutations define an apparent frameshift hot spot at codons 321-322. Overall, however, we detected mutations in the HPS gene in only about half of non-Puerto Rican patients, and we present evidence that suggests locus heterogeneity for HPS.

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

IMPORTANCEnGaucher disease type 1 is characterized by hepatosplenomegaly, anemia, thrombocytopenia, and skeletal disease. A safe, effective oral therapy is needed.nnnOBJECTIVEnTo determine whether eliglustat, a novel oral substrate reduction therapy, safely reverses clinical manifestations in untreated adults with Gaucher disease type 1.nnnDESIGN, SETTING, AND PARTICIPANTSnPhase 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.nnnINTERVENTIONSnPatients were stratified by spleen volume and randomized 1:1 to receive eliglustat (50 or 100 mg twice daily; nu2009=u200920) or placebo (nu2009=u200920) for 9 months.nnnMAIN OUTCOMES AND MEASURESnThe 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.nnnRESULTSnAll 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%; Pu2009<u2009.001). 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; Pu2009<u2009.001), 6.64% decrease in liver volume (95% CI, -11.37% to -1.91%; Pu2009=u2009.007), and 41.06% increase in platelet count (95% CI, 23.95%-58.17%; Pu2009<u2009.001). 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.nnnCONCLUSIONS AND RELEVANCEnAmong 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.nnnTRIAL REGISTRATIONnclinicaltrials.gov Identifier: NCT00891202.

A Phase 3, multicenter, open-label, switchover trial to assess the safety and efficacy of taliglucerase alfa, a plant cell-expressed recombinant human glucocerebrosidase, in adult and pediatric patients with Gaucher disease previously treated with imiglucerase

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 2years. Patients with stable disease were offered taliglucerase alfa treatment using the same dose (9-60U/kg body weight) and regimen of administration (every 2weeks) 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 9months 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 www.clinicaltrials.gov as # NCT00712348.

Overexpression of SOCS-2 and SOCS-3 genes reverses erythroid overgrowth and IGF-I hypersensitivity of primary polycythemia vera (PV) cells

Polycythemia vera (PV), an acquired, chronic, clonal disorder arising in a multipotential hematopoietic progenitor cell, is characterized by hyperplasia of three major myeloid lineages, with a pronounced increase in cells of the erythroid lineage. Erythroid progenitor cells in PV are strikingly hypersensitive to insulin-like growth factor-I (IGF-I); this effect is specific and is mediated through the IGF-I receptor. To investigate the possibility that in PV the increase in number of erythroid progenitors and their hypersensitivity to IGF-I result from a defect in negative regulation of cytokine activity, we examined the expression of members of the SOCS gene family. Circulating mononuclear cells, grown in serum-free methylcellulose medium in the presence of IGF-I, produced BFU-E-derived colonies whose cells revealed a reduction of SOCS-2 and SOCS-3 expression in PV only. Overexpression of these genes in transfected PV cells reduced their erythroid overgrowth and IGF-I hypersensitivity. We hypothesize that a defect in expression of SOCS-2 and SOCS-3 genes may be crucial for the IGF-I hypersensitivity and progressive increase in erythroid cell population size characteristic of PV.

Enzyme replacement therapy with taliglucerase alfa: 36‐month safety and efficacy results in adult patients with Gaucher disease previously treated with imiglucerase

Taliglucerase alfa is the first available plant cell‐expressed human recombinant therapeutic protein. It is indicated for treatment of patients with type 1 Gaucher disease (GD) in adult and pediatric patients in several countries. Study PB‐06‐002 examined the safety and efficacy of taliglucerase alfa for 9 months in patients who previously received imiglucerase. The results of adult patients from Study PB‐06‐002 who continued receiving taliglucerase alfa in extension Study PB‐06‐003 for up to 36 months are reported here. Eighteen patients received at least one dose of taliglucerase alfa in Study PB‐06‐003; 10 patients completed 36 total months of therapy, and four patients who transitioned to commercial drug completed 30–33 months of treatment. In patients who completed 36 total months of treatment, mean percent (±standard error) changes from baseline/time of switch to taliglucerase alfa to 36 months were as follows: hemoglobin concentration, −1.0% (±1.9%; nu2009=u200910); platelet count, +9.3% (±9.8%; nu2009=u200910); spleen volume measured in multiples of normal (MN), −19.8% (±9.9%; nu2009=u20097); liver volume measured in MN, +0.9% (±5.4%; nu2009=u20098); chitotriosidase activity, −51.5% (±8.1%; nu2009=u200910); and CCL18 concentration, −36.5 (±8.0%; nu2009=u200910). Four patients developed antidrug antibodies, including one with evidence of neutralizing activity in vitro. All treatment‐related adverse events were mild or moderate and transient. The 36‐month results of switching from imiglucerase to taliglucerase alfa treatment in adults with GD provide further data on the clinical safety and efficacy of taliglucerase alfa beyond the initial 9 months of the original study. www.clinicaltrials.gov identifier NCT00705939. Am. J. Hematol. 91:661–665, 2016.

Evaluation of disease burden and response to treatment in adults with type 1 gaucher disease using a validated disease severity scoring system (DS3)

BackgroundGD1-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.MethodsWe 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.ResultsPatient 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.ConclusionsDS3 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.

Long-term efficacy and safety results of taliglucerase alfa up to 36 months in adult treatment-naïve patients with Gaucher disease.

Taliglucerase alfa is an intravenous enzyme replacement therapy approved for treatment of type 1 Gaucher disease (GD), and is the first available plant cell–expressed recombinant therapeutic protein. Herein, we report long‐term safety and efficacy results of taliglucerase alfa in treatment‐naïve adult patients with GD. Patients were randomized to receive taliglucerase alfa 30 or 60 U/kg every other week, and 23 patients completed 36 months of treatment. Taliglucerase alfa (30 U/kg; 60 U/kg, respectively) resulted in mean decreases in spleen volume (50.1%; 64.6%) and liver volume (25.6%; 24.4%) with mean increases in hemoglobin concentration (16.0%; 35.8%) and platelet count (45.7%; 114.0%), and mean decreases in chitotriosidase activity (71.5%; 82.2%). All treatment‐related adverse events were mild to moderate in intensity and transient. The most common adverse events were nasopharyngitis, arthralgia, upper respiratory tract infection, headache, pain in extremity, and hypertension. These 36‐month results of taliglucerase alfa in treatment‐naïve adult patients with GD demonstrate continued improvement in disease parameters with no new safety concerns. These findings extend the taliglucerase alfa clinical safety and efficacy dataset. www.clinicaltrials.gov identifier NCT00705939. Am. J. Hematol. 91:656–660, 2016.

Long‐term safety and efficacy results of taliglucerase alfa up to 36 months in adult treatment‐naïve patients with Gaucher disease

Taliglucerase alfa is an intravenous enzyme replacement therapy approved for treatment of type 1 Gaucher disease (GD), and is the first available plant cell–expressed recombinant therapeutic protein. Herein, we report long‐term safety and efficacy results of taliglucerase alfa in treatment‐naïve adult patients with GD. Patients were randomized to receive taliglucerase alfa 30 or 60 U/kg every other week, and 23 patients completed 36 months of treatment. Taliglucerase alfa (30 U/kg; 60 U/kg, respectively) resulted in mean decreases in spleen volume (50.1%; 64.6%) and liver volume (25.6%; 24.4%) with mean increases in hemoglobin concentration (16.0%; 35.8%) and platelet count (45.7%; 114.0%), and mean decreases in chitotriosidase activity (71.5%; 82.2%). All treatment‐related adverse events were mild to moderate in intensity and transient. The most common adverse events were nasopharyngitis, arthralgia, upper respiratory tract infection, headache, pain in extremity, and hypertension. These 36‐month results of taliglucerase alfa in treatment‐naïve adult patients with GD demonstrate continued improvement in disease parameters with no new safety concerns. These findings extend the taliglucerase alfa clinical safety and efficacy dataset. www.clinicaltrials.gov identifier NCT00705939. Am. J. Hematol. 91:656–660, 2016.

A double-blind, randomized, placebo-controlled trial studying the effects of Saccharomyces boulardii on the gastrointestinal tolerability, safety, and pharmacokinetics of miglustat

BackgroundGastrointestinal (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.MethodsIn 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 100xa0mgxa0t.i.d. + placebo; treatment B - miglustat 100xa0mgxa0t.i.d. + S. boulardii [500xa0mg, 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.ResultsTwenty-one subjects received randomized therapy in each treatment sequence (total Nu2009=u200942), and overall, 37 (88xa0%) subjects completed the study. The total number of diarrhea days was <1.5 for both treatment sequences, and approximately 60xa0% of subjects did not experience diarrhea during either treatment period. The mean (SD) number of diarrhea days was lower with miglustatu2009+u2009S. boulardii (0.8 [2.4] days) than with miglustatu2009+u2009placebo (1.3 [2.4] days), but the paired treatment difference was not statistically significant (−0.5 [2.4] days; pu2009=u20090.159). However, a significant treatment difference (−0.7 [1.9]; pu2009<u20090.05) was identified after post hoc exclusion of a clear outlier who had a very high number of diarrhea days (nu2009=u200913) and inconsistent GI tolerability reporting. The incidence of the GI AEs was higher with miglustatu2009+u2009placebo (82xa0%) than with miglustatu2009+u2009S. boulardii (73xa0%). There were no between-treatment differences in miglustat pharmacokinetics.ConclusionsAlthough 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.