Pharmacokinetics, Pharmacodynamics, and Safety of a Long-Acting Human Growth Hormone (MOD-4023) in Healthy Japanese and Caucasian Adults

Daily injections of growth hormone (GH) as replacement therapy in GH-deficient (GHD) patients may cause poor compliance and inconvenience. C-terminal peptide–modified human GH (MOD­4023) has been developed for once­weekly administration in GHD adults and children. In the present study, the pharmacokinetics (PK) and pharmacodynamics (PD) of a single subcutaneous dose of MOD­4023 were evaluated in healthy Caucasian and Japanese adults, using a phase 1 double-blind, vehicle-controlled, randomized study design. The study was conducted in 42 healthy Japanese (n = 21) and Caucasian (n = 21) men receiving either MOD-4023 at a dose of 2.5, 7.5, or 15 mg or vehicle. In the 2.5- and 7.5-mg cohorts, no differences in mean MOD-4023 serum concentration were found between Japanese and Caucasian subjects. A comparison of PK parameters in the 15-mg group suggests a slower absorption rate of MOD-4023 in Japanese subjects. PD analysis showed no apparent differences in IGF-1 and IGFBP-3 plasma concentrations between the Japanese and Caucasian subjects and indicated that a dose of 15 mg achieved the maximal effect in both ethnic groups. MOD-4023 demonstrated a favorable safety profile and local tolerance following single-dose subcutaneous administration. This study provides additional support for the development of MOD-4023 as a long-acting human growth hormone formulation for once-weekly administration.