-1 is bound to six IGF binding proteins, with > 80% bound as a complex with IGFBP-3 and an acid-labile subunit. IGFBP-3 is greatly reduced in subjects with severe Primary IGFD, resulting in increased clearance of IGF-1 in these subjects relative to healthy subjects. The total IGF-1 volume of distribution after subcutaneous administration in subjects with severe Primary IGFD is estimated to be 0.257 (± 0.073) L/kg at an INCRELEX® dose of 0.045 mg/kg, and is estimated to increase as the dose of INCRELEX® increases.
Elimination – IGF-1 is metabolized by both liver and kidney. The mean terminal t1/2 after single subcutaneous administration of 0.12 mg/kg INCRELEX® in pediatric subjects with severe Primary IGFD is estimated to be 5.8 hours. Clearance of INCRELEX® is inversely proportional to IGF binding protein-3 (IGFBP-3) levels. CL/F is estimated to be 0.04 L/hr/kg at 0.5 micrograms/mL of IGFBP-3, and 0.01 L/hr/kg at 3 micrograms/mL IGFBP-3; the latter is the median IGFBP-3 in subjects with normal IGF-1 serum levels.
Gender – In children with Primary IGFD there were no apparent differences between males and females in the pharmacokinetics of INCRELEX®.
Race –The effect of race on pharmacokinetics of INCRELEX® has not been studied.
Summary of INCRELEX® Single-Dose Pharmacokinetic Parameters in Children with Severe Primary IGFD (0.12 mg/kg, SC) Cmax
(ng/mL) Tmax
(hr) AUC0-8
(hr*ng/mL) t1/2
(hr) Vd/F
(L/kg) CL/F
(L/hr/kg)
n 3 3 3 3 12* 12*
Cmax = maximum concentration; Tmax = time of maximum concentration; AUC0-8 = area under the curve; t1/2 = half-life; Vd/F = apparent volume of distribution; CL/F = apparent systemic clearance; SC = subcutaneous injection; CV% = coefficient of variation in %.
Male/female data combined, ages 12 to 22 years.
PK parameters based on baseline adjusted plasma concentrations.
* Data represents 3 subjects each at doses 0.015, 0.03, 0.06, and 0.12 mg/kg SC.
Mean 234 2 2932 5.8 0.257 0.0424
CV% 23 0 50 64 28 38
Mean Total IGF-1 Concentration after a Single Subcutaneous Dose of INCRELEX® in Children with Severe Primary IGFD (0.06 mg/kg and 0.12 mg/kg, n = 3 per group)
Renal impairment– No studies have been conducted in Primary IGFD children with renal impairment.
Hepatic impairment– No studies have been conducted to determine the effect of hepatic impairment on the pharmacokinetics of rhIGF-1 in Primary IGFD children with hepatic impairment.
13 NONCLINICAL TOXICOLOGY
13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility
Carcinogenesis: INCRELEX® was tumorigenic in rats in a study using doses of 0, 0.25, 1, 4, and 10 mg/kg/day by subcutaneous injection for up to 2 years. The incidence of adrenal medullary hyperplasia and pheochromocytoma increased in male rats given ≥1 mg/kg/day (≥ 1 times the clinical exposure with the maximum recommended human dose [MRHD] based on AUC) and in female rats at all dose levels (≥ 30% of the clinical exposure with the MRHD based on AUC). The incidence of keratoacanthoma in the skin increased in male rats given 4 and 10 mg/kg/day (≥ 4 times the MRHD). The incidence of mammary gland carcinoma in male rats increased in animals treated with 10 mg/kg/day (7 times the MRHD based on AUC). Only doses that exceeded the maximum tolerated dose (MTD) (based on excess mortality secondary to IGF-1 induced hypoglycemia) caused skin and mammary tumors.
Mutagenesis: I |
