ELELYSO (Page 3 of 4)

12 CLINICAL PHARMACOLOGY

12.1 Mechanism of Action

Gaucher disease is an autosomal recessive disorder caused by mutations in the human glucocerebrosidase gene, which results in a reduced activity of the lysosomal enzyme glucocerebrosidase. Glucocerebrosidase catalyzes the conversion of the sphingolipid glucocerebroside into glucose and ceramide. The enzymatic deficiency results in accumulation of substrate glucocerebroside primarily in the lysosomal compartment of macrophages, giving rise to foam cells or “Gaucher cells,” which accumulate in the liver, spleen and bone marrow.

ELELYSO, a long term enzyme replacement therapy, is a recombinant analog of human lysosomal glucocerebrosidase that catalyzes the hydrolysis of glucocerebroside to glucose and ceramide, reducing the amount of accumulated glucocerebroside. ELELYSO uptake into cellular lysosomes is mediated by binding of ELELYSO mannose oligosaccharide chains to specific mannose receptors on the cell surface leading to internalization and subsequent transport to the lysosomes.

12.3 Pharmacokinetics

Pharmacokinetics of taliglucerase alfa were evaluated in 38 patients (29 adult and 9 pediatric patients) who received intravenous infusions of ELELYSO 30 units/kg or 60 units/kg every other week. ELELYSO 30 units/kg is not a recommended dose in treatment-naïve Gaucher disease patients [see Dosage and Administration (2.1)]. The pharmacokinetic parameters in adult and pediatric patients are summarized in Table 3.

In adult Type 1 Gaucher disease patients treated with ELELYSO 30 units/kg or 60 units/kg (N=29) every other week as initial therapy, pharmacokinetics were determined with the first dose and at Week 38 of treatment. The pharmacokinetics of taliglucerase alfa appeared to be nonlinear with a greater than dose-proportional increase in exposure at the doses studied.

No significant accumulation or change in taliglucerase alfa pharmacokinetics over time from Weeks 1 to 38 was observed with repeated dosages of 30 units/kg or 60 units/kg every other week. Based on the limited data, there were no significant pharmacokinetic differences between male and female patients in this study.

The pharmacokinetics of taliglucerase alfa were evaluated in 9 pediatric patients 4 to 17 years of age with Type 1 Gaucher disease who were treated with ELELYSO for 10 to 27 months. Six of the 9 patients were treatment-naïve, and 3 patients were switched from imiglucerase. In both the 30 units/kg and 60 units/kg dose groups, clearance values in pediatric patients were similar to those in adult patients. AUC values in pediatric patients were lower than AUC values in adult patients, due to weight-based dosing of taliglucerase alfa and lower body weights in pediatric patients.

Table 3: Taliglucerase Alfa Pharmacokinetic Parameters after Repeated Dosing in Adult and Pediatric Patients with Type 1 Gaucher Disease
Pediatric Patients (N=9)Median (Range) Adult Patients at Week 38 (N=29)Median (Range)
*
n = 14
Values were derived from concentration data expressed in ng/mL
30 units/kgn = 5 60 units/kgn = 4 30 units/kgn = 14 60 units/kgn = 15
Age (years) 15 (10, 17) 11 (4, 16) 35 (19, 74) 33 (19, 58)
Weight (kg) 44.3 (22.8, 71.0) 28.6 (16.5, 50.4) 72.5 (51.5, 99.5) 73.5 (58.5, 87.0)*
AUC0–∞ (ng*h/mL) 1416 (535, 1969) 2984 (1606, 4273) 2007 (1007, 10092) 6459 (2548, 21020)*
T1/2 (min) 37.1 (22.5, 56.8) 32.5 (18.0, 42.9) 18.9 (9.20, 57.9) 28.7 (11.3, 104)*
CL (L/h) 30.5 (17.4, 37.8) 15.8 (11.7, 24.9) 30.5 (6.79, 68.0) 18.5 (6.20, 37.9)*
Vss (L) 14.9 (10.1, 35.6) 8.80 (3.75, 21.4) 11.7 (2.3, 22.7) 10.7 (1.4, 18.5)*

13 NONCLINICAL TOXICOLOGY

13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility

Long-term studies in animals to evaluate carcinogenic potential or studies to evaluate mutagenic potential have not been performed with taliglucerase alfa. In a male and female fertility study in rats, taliglucerase alfa did not cause any significant adverse effect on male or female fertility parameters up to a maximum dose of 55 mg/kg/day (about 5 times the recommended human dose of 60 units/kg based on the body surface area).

14 CLINICAL STUDIES

14.1 Clinical Trials of ELELYSO as Initial Therapy

Clinical Trial in Patients 19 Years and Older

The safety and efficacy of ELELYSO were assessed in 31 adult patients with Type 1 Gaucher disease. The trial was a 9-month, multi-center, double-blind, randomized trial in patients with Gaucher disease-related enlarged spleens (>8 times normal) and thrombocytopenia (<120,000 /mm3). Sixteen patients had enlarged livers and ten patients had anemia at baseline. All patients were naïve to ERT. Patients with severe neurological symptoms were excluded from the trial. Patients were 19 to 74 years of age (mean age 36 years), and 48% were male. Patients were randomized to receive ELELYSO at a dosage of either 30 units/kg (n=15) or 60 units/kg (n=16) every other week. The recommended dosage in treatment-naïve adult patients is 60 units/kg every other week. ELELYSO 30 units/kg every other week is not a recommended dosage [see Dosage and Administration (2.1)].

Table 4 shows the baseline values and mean (SD) changes in clinical parameters (spleen volume, liver volume, platelet count, and hemoglobin) after 9 months of treatment with ELELYSO. For all clinical trials, liver and spleen volumes were measured by MRI and are reported as percentage of body weight (%BW) and multiples of normal (MN). The observed change from baseline in the primary endpoint, reduction in spleen volume, was considered to be clinically meaningful in light of the natural history of untreated Gaucher disease.

Table 4: Mean (SD *) Changes in Clinical Parameters from Baseline to 9 Months in Treatment-Naïve Adults with Type 1 Gaucher Disease Initiating Therapy with ELELYSO (N=31)
Clinical Parameter 30 units/kg (n=15)Mean (SD) 60 units/kg (n=16)Mean (SD)
*
SD = standard deviation
The recommended ELELYSO dosage in treatment-naïve adult patients is 60 units/kg every other week. ELELYSO 30 units/kg every other week is not a recommended dosage. [see Dosage and Administration (2.1)]
%BW = percentage of body weight
§
MN = multiples of normal
Spleen Volume (%BW ) Baseline 3.1 (1.5) 3.3 (2.7)
Month 9 2.2 (1.3) 2.1 (1.9)
Change -0.9 (0.4) -1.3 (1.1)
Spleen Volume (MN §) Baseline 15.4 (7.7) 16.7 (13.4)
Month 9 11.1 (6.3) 10.4 (9.4)
Change -4.5 (2.1) -6.6 (5.4)
Liver Volume (%BW) Baseline 4.2 (0.9) 3.8 (1.0)
Month 9 3.6 (0.7) 3.1 (0.7)
Change -0.6 (0.5) -0.6 (0.4)
Liver Volume (MN) Baseline 1.7 (0.4) 1.5 (0.4)
Month 9 1.4 (0.3) 1.2 (0.3)
Change -0.2 (0.2) -0.3 (0.2)
Platelet Count (mm3) Baseline 75,320 (40,861) 65,038 (28,668)
Month 9 86,747 (50,989) 106,531 (53,212)
Change 11,427 (20,214) 41,494 (47,063)
Hemoglobin (g/dl) Baseline 12.2 (1.7) 11.4 (2.6)
Month 9 14.0 (1.4) 13.6 (2.0)
Change 1.6 (1.4) 2.2 (1.4)

Twenty-six of the 31 patients in this 9-month clinical trial continued blinded treatment with ELELYSO in an extension trial for a total treatment duration of 24 months. The following data are the changes in clinical parameters from baseline to Month 24 for the 30 units/kg (n=12) and 60 units/kg (n=14) dose groups, respectively: mean (SD) spleen volume (%BW) decreased by 1.4 (0.6) and 2.0 (2.0), in MN by 6.8 (3.0) and 10.2 (9.8); hemoglobin increased by 1.3 (1.7) g/dL and 2.4 (2.3) g/dL; liver volume (%BW) decreased by 1.1 (0.5) and 1.0 (0.7), in MN by 0.4 (0.2) and 0.4 (0.3 and platelet count increased 28,433 (31,996) /mm3 and 72,029 (68,157) /mm3. Twenty-three of the 26 patients who continued open-label treatment with ELELYSO for additional 12 months demonstrated stability in these clinical parameters.

Clinical Trial in Patients 16 years and Younger

The safety and efficacy of ELELYSO were assessed in 9 pediatric patients with Type 1 Gaucher disease. The trial was a 12-month, multi-center, double-blind, randomized study in treatment-naïve patients. Patients were 2 to 13 years of age (mean age 8.1 years), and 67% were male. Patients were randomized to receive ELELYSO at a dosage of either 30 units/kg (n=4) or 60 units/kg (n=5) every other week. The recommended ELELYSO dosage in treatment-naïve pediatric patients is 60 units/kg every other week. ELELYSO 30 units/kg every other week is not a recommended dosage [see Dosage and Administration (2.1)].

The following data are the changes [median (Q1, Q3)] in clinical parameters from baseline to Month 12 for the 60 units/kg dose group (n=5): spleen volume decreased from 18.4 (14.2, 35.1) MN to 11.0 (8.3, 14.5) MN; hemoglobin increased from 11.1 (9.2, 11.3) g/dL to 11.7 (11.5, 12.9) g/dL; liver volume decreased from 2.1 (2.0, 2.3) MN to 1.6 (1.5, 1.9) MN; platelet count increased from 80,000 (79,000, 87,000)/mm3 to 131,000 (119,000, 215,000)/mm3.

Nine pediatric patients in the 12-month clinical trial continued blinded treatment with ELELYSO in an extension trial for a total treatment duration of 24 months. The following data are the changes [median (Q1, Q3)] in clinical parameters from baseline to Month 24 for the 60 units/kg dose group (n=5): spleen volume decreased by 19.0 (8.3, 41.2) MN; hemoglobin increased by 2.5 (1.9, 3.0) g/dL; liver volume decreased by 0.8 (0.6, 1.1) MN; and platelet count increased by 76,000 (67,000, 100,000)/mm3.

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