Relative Bioavailability of a Single 4-mg Dose of Somatropin Administered by Subcutaneous Injection or by Needle-free Device and Coadministered With the Growth Hormone Inhibitor Octreotide Acetate in Healthy Adult Subjects.

This study evaluated the relative bioavailability of somatropin delivered with a needle-free device compared with traditional SC injection. METHODS: In this randomized, single-dose, crossover study, healthy adults aged 18 to 35 years received single 4-mg doses of somatropin via a needle-free device or SC injection, along with octreotide to suppress endogenous growth hormone production. Blood samples were analyzed for serum somatropin and insulin-like growth factor-1 (IGF-1) concentrations over 24 hours after somatropin dosing. Pharmacokinetic and pharmacodynamic parameters were evaluated by using noncompartmental methods, and bioequivalence was determined based on ln transformation of the AUC0-24, AUC0-∞, Cmax, area under the effect-time curve from time 0 to 24 hours (AUEC0-24), and maximum effect concentration (Emax). Bioequivalence was concluded if the 90% CIs of the needle-free device compared with the SC injection, constructed by using the two 1-sided hypotheses at the α = 0.05 level, for these pharmacokinetic/pharmacodynamic parameters fell within the 80.00% to125.00% regulatory acceptance range. FINDINGS: A total of 57 subjects completed both study periods and were included in the pharmacokinetic analyses. Point estimates (90% CIs) of the geometric mean ratio (needle-free device/SC injection) based on serum somatropin were 1.013 (0.987-1.040) for AUC0-24, 1.012 (0.986-1.038) for AUC0-∞, and 1.200 (1.137-1.267) for Cmax. For IGF-1, baseline-corrected...
Source: Clinical Therapeutics - Category: Drugs & Pharmacology Authors: Tags: Clin Ther Source Type: research