M. Judith Peterschmitt

A phase 2 study of eliglustat tartrate (Genz-112638), an oral substrate reduction therapy for Gaucher disease type 1

Eliglustat tartrate (Genz-112638), a specific inhibitor of glucosylceramide synthase, is under development as an oral substrate reduction therapy for Gaucher disease type 1 (GD1). A multinational, open-label, single-arm phase 2 study of 26 GD1 patients (16 female, 10 male; mean age, 34 years) evaluated the efficacy, safety, and pharmacokinetics of eliglustat tartrate administered twice daily by mouth at 50- or 100-mg doses based on plasma drug concentrations. Entry criteria required splenomegaly with thrombocytopenia and/or anemia. The composite primary efficacy end point required improvement after 52 weeks in at least 2 of these 3 disease manifestations and was met by 77% (95% confidence interval [CI] = 58%-89%) of all patients and 91% (95% CI = 72%-98%) of the 22 patients completing 52 weeks. Statistically significant improvements occurred in mean hemoglobin level (1.62 g/dL; 95% CI =1.05-2.18 g/dL), platelet count (40.3%; 95% CI = 23.7-57.0 g/dL), spleen volume (-38.5%; 95% CI = -43.5%--33.5%), liver volume (-17.0%; 95% CI = -21.6%-12.3%), and lumbar spine bone mineral density (0.31 Z-score; 95% CI = 0.09-0.53). Elevated biomarkers (chitotriosidase; chemokine CCL18; angiotensin-converting enzyme; tartrate-resistant acid phosphatase) decreased by 35% to 50%. Plasma glucosylceramide and ganglioside GM3 normalized. Eliglustat tartrate was well tolerated: 7 mild, transient adverse events in 6 patients were considered treatment-related. Individual pharmacokinetics varied; mean time to maximal observed concentration was 2.3 hours and mean half-life was 6.8 hours. Eliglustat tartrate appears to be a promising oral treatment for GD1.

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.

Safety, tolerability, and pharmacokinetics of eliglustat tartrate (Genz-112638) after single doses, multiple doses, and food in healthy volunteers.

Three phase 1 studies of eliglustat tartrate (Genz‐112638), an oral inhibitor of glucosylceramide synthase under development for treating Gaucher disease type 1 (GD1), evaluated the safety, tolerability, and pharmacokinetics in healthy volunteers after escalating single doses (n = 99), escalating multiple doses (n = 36), and food (n = 24). Eliglustat tartrate was well tolerated at single doses ≤20 mg/kg and multiple doses ≤200 mg bid, with 50 mg bid producing plasma concentrations in the predicted therapeutic range. No serious adverse events occurred. Mild to moderate events of nausea, dizziness, and vomiting increased in frequency with escalating single and multiple doses. Single doses ≥10 mg/kg caused mild increases in electrocardiogram PR, QRS, and QT/QTc intervals. Single‐dose pharmacokinetics showed dose linearity but not proportionality. Maximum plasma concentrations occurred at ∼2 hours, followed by a monophasic decline with a ∼6‐hour terminal half‐life. Unchanged drug in 8‐hour urine collections was <1.5% of administered doses. Food did not significantly affect the rate or extent of absorption. Multiple‐dose pharmacokinetics was nonlinear, showing higher than expected plasma drug concentrations. Steady state was reached ∼60 hours after bid dosing. Higher drug exposure occurred in slower CYP2D6 metabolizers. Based on favorable results in healthy participants, a phase 2 trial of eliglustat tartrate was initiated in GD1 patients.

A pooled analysis of adverse events in 393 adults with Gaucher disease type 1 from four clinical trials of oral eliglustat: Evaluation of frequency, timing, and duration

Eliglustat, an oral substrate reduction therapy, is a first-line therapy for adults with Gaucher disease type 1 and a compatible CYP2D6 metabolizer phenotype. Clinicians have requested more information about frequency, timing, and duration of adverse events associated with eliglustat. Adverse event data as of January 31, 2013 for all patients who received at least one dose of eliglustat were pooled from four eliglustat clinical trials (393 patients representing 535 patient-years of exposure). The following 10 adverse events noted in the eliglustat US Prescribing Information (USPI) and EU Summary of Product Characteristics (SmPC) were evaluated with regard to frequency, drug-relatedness, severity, seriousness, duration, and timing of onset: headache, arthralgia, diarrhea, nausea, fatigue, flatulence, abdominal pain, upper abdominal pain, back pain, and extremity pain. Of 393 patients, 334 experienced one or more adverse events. Most patients (92%) continued taking eliglustat; 3% withdrew from a trial due to an adverse event. Among the 10 adverse events evaluated, none was reported as serious and none resulted in discontinuing treatment; most were mild or moderate, reported only once, and not considered eliglustat-related. The majority of adverse events noted in the eliglustat USPI and SmPC were non-serious, occasional, non-severe, and did not lead to drug discontinuation.

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.

Clinical response to eliglustat in treatment-naïve patients with Gaucher disease type 1: Post-hoc comparison to imiglucerase-treated patients enrolled in the International Collaborative Gaucher Group Gaucher Registry

Eliglustat is a recently approved oral therapy in the United States and Europe for adults with Gaucher disease type 1 who are CYP2D6 extensive, intermediate, or poor metabolizers (> 90% of patients) that has been shown to decrease spleen and liver volume and increase hemoglobin concentrations and platelet counts in untreated adults with Gaucher disease type 1 and maintain these parameters in patients previously stabilized on enzyme replacement therapy. In a post-hoc analysis, we compared the results of eliglustat treatment in treatment-naïve patients in two clinical studies with the results of imiglucerase treatment among a cohort of treatment-naïve patients with comparable baseline hematologic and visceral parameters in the International Collaborative Gaucher Group Gaucher Registry. Organ volumes and hematologic parameters improved from baseline in both treatment groups, with a time course and degree of improvement in eliglustat-treated patients similar to imiglucerase-treated patients.

Stability is maintained in adults with Gaucher disease type 1 switched from velaglucerase alfa to eliglustat or imiglucerase: A sub-analysis of the eliglustat ENCORE trial

Gaucher disease type 1 is an autosomal recessive disorder caused by deficient activity of the lysosomal enzyme acid β-glucosidase resulting in accumulation of glucosylceramide and clinical manifestations of anemia, thrombocytopenia, hepatosplenomegaly, and skeletal disease. The historic standard of care is intravenous recombinant enzyme therapy with imiglucerase. Eliglustat, an oral substrate reduction therapy, is a first-line treatment for adults with Gaucher disease type 1 who have a compatible CYP2D6-metabolizer phenotype (≈ 95% of patients). The 12-month ENCORE trial (NCT00943111) found eliglustat non-inferior to imiglucerase in maintaining stability in adult Gaucher patients previously stabilized after ≥ 3 years of enzyme therapy (imiglucerase or velaglucerase alfa). This post-hoc analysis examined safety and efficacy in the 30 ENCORE patients who were receiving velaglucerase alfa at study entry and were randomized to eliglustat (n = 22) or imiglucerase (n = 8). Efficacy and safety in velaglucerase alfa-transitioned patients were consistent with the full ENCORE trial population; 90% of patients switched to eliglustat and 88% of patients switched to imiglucerase met the composite endpoint (stable hemoglobin concentration, platelet count, spleen volume, and liver volume). Clinical stability was maintained for 12 months in Gaucher disease type 1 patients in the ENCORE trial who switched from velaglucerase alfa to either eliglustat or imiglucerase.

Once- versus twice-daily dosing of eliglustat in adults with Gaucher disease type 1: The Phase 3, randomized, double-blind EDGE trial

Eliglustat is a first-line oral therapy for adults with Gaucher disease type 1 (GD1) with compatible CYP2D6-metabolizer phenotypes (>90% of patients). The randomized, double-blind EDGE trial (NCT01074944, Sanofi Genzyme) evaluated once-daily eliglustat dosing compared with the approved twice-daily regimen at the same total daily dose in adults with GD1. Subjects received twice-daily dosing during a 6- to 18-month lead-in period. Only subjects who attained prespecified treatment goals for hemoglobin, platelet count, spleen and liver volumes, and bone symptoms during the lead-in period were randomized to once- or twice-daily dosing. Of 170 enrolled patients, 156 completed the lead-in period and 131 met all requirements to enter the double-blind treatment period. To achieve the composite primary endpoint in the double-blind period, patients had to maintain clinical stability relative to baseline on all five endpoints (hemoglobin, platelet count, spleen and liver volumes, and bone symptoms) and meet pharmacokinetic and other tolerability requirements as determined by the investigator after 1year of eliglustat treatment. After 1year, 80.4% (95% CI: 67.6, 89.8) of once-daily patients were stable compared with 83.1% (95% CI: 71.0, 91.6) of twice-daily patients. The 95% CI for the mean difference of -2.7% between groups was -17.7, 11.9. Because the lower bound of the CI exceeded the pre-defined non-inferiority margin of -15%, once-daily dosing could not be declared non-inferior to twice-daily dosing. Both once-daily and twice-daily patients maintained mean values for hematologic and visceral measures within established therapeutic goals during the double-blind treatment and long-term extension periods. Eliglustat was generally well-tolerated during this long-term trial (mean treatment duration: 3.3years), with just four withdrawals (2%) for related adverse events (AE), and similar AE profiles for both dosing regimens. Patients on twice-daily eliglustat showed more stability overall, and this dose regimen was better tolerated, confirming the dosing regimen for most patients specified in the drug label.

Outcomes after 8 years of eliglustat therapy for Gaucher disease type 1: Final results from the Phase 2 trial

Eliglustat is a first‐line oral therapy for adults with Gaucher disease type 1 (GD1) and poor, intermediate or extensive CYP2D6‐metabolizer phenotypes (>90% of patients). We report the final results of a Phase 2 trial and extension (NCT00358150) in previously untreated adult GD1 patients who had splenomegaly with thrombocytopenia and/or anemia and received 50 or 100 mg eliglustat tartrate (equivalent to 42 or 84 mg eliglustat) twice daily for 8 years. In total, 19 of 26 patients completed the trial. After 8 years of eliglustat, mean spleen and liver volumes decreased by 69% and 34%, respectively. Mean hemoglobin concentration and platelet count increased by 2.2 g/dL and 113%, respectively. All patients met at least 3 of 4 therapeutic goals established for patients on long‐term enzyme replacement therapy. Mean final values for patients with severe splenomegaly (n = 6), moderate‐to‐severe anemia (n = 6), or severe thrombocytopenia (n = 8) were similar to patients with milder disease at baseline and within long‐term therapeutic goal thresholds. Biomarker median percent changes from baseline were ‐91% for chitotriosidase, ‐87% for CCL18, ‐92% for glucosylsphingosine, and ‐80% for plasma glucosylceramide. Mean lumbar spine T‐score increased by 0.96, moving from the osteopenic to the normal range. Mean quality‐of‐life scores, mostly below normal at baseline, moved into ranges seen in healthy adults. Eliglustat was well‐tolerated; 98% of adverse events were mild or moderate and 94% were considered unrelated to treatment. Clinically meaningful improvements in all parameters continued or were maintained over 8 years, with the largest margins of improvement seen in the most severely affected patients.