Background and objective: At present, the deficiency of β-cell function is progressive in patients with type 2 diabetes mellitus. Exenatide cannot only control blood glucose well, but also promotes the regeneration and proliferation of islet β-cells and improves the function of β cells. However, it needs to be given twice a day, and there are many adverse reactions such as nausea. PEGylated exenatide (study code: PB-119) needs to be administered only once a week. The purpose of this experiment was to evaluate the safety, pharmacokinetics and pharmacodynamics of an escalating dose regimen of subcutaneous PEGylated exenatide injections in healthy subjects.
Methods: Twelve healthy young adult subjects in each group received once-weekly subcutaneous injections of 165 μg, 330 μg, and 660 μg PEGylated exenatide for 6 weeks. Plasma drug concentration was determined in venous blood collected across selected time points. Safety and tolerability were evaluated by monitoring adverse events, laboratory parameters, and electrocardiogram. Blood glucose, insulin, glucagon and C peptide were monitored at different time points to evaluate the pharmacodynamics of PEGylated exenatide.
Results: A total of 11, 10, and 12 subjects completed the study in 165 µg, 330 µg, and 660 µg dose groups, respectively. After 6 consecutive weeks of administration, the t1/2 in the 165 μg, 330 μg, and 660 µg dose groups was 55.67 ± 11.03 h, 56.99 ± 21.37 h, and 54.81 ± 13.87 h, respectively. The Cavg was 4.22 ± 0.78 ng/ml, 6.03 ± 1.43 ng/ml, and 10.50 ± 3.06 ng/ml, respectively. AUCss was 708.59 ± 131.87 h•ng/ml, 1012.63 ± 240.79 h•ng/ml, and 1763.81 ± 514.50 h•ng/ml, respectively. The accumulation index was 1.15 ± 0.07, 1.17 ± 0.11, and 1.14 ± 0.07. The CLss/F was 241.25 ± 51.13 ml/h, 341.53 ± 73.62 ml/h, and 450.06 ± 313.76 ml/h, respectively. A total of 10 of 36 (27.78%) subjects in the three dose groups developed specific antibodies after consecutive subcutaneous injections of PEGylated exenatide. The Cavg and Cmax were higher than those of antibody-negative subjects. Furthermore, in antibody-positive subjects, CLss/F, t1/2, AUCτ, accumulation index, MRT(0-inf) and other parameters were lower than those of antibody-negative subjects. In the 165 μg dose group, two subjects (16.67%) experienced 4 adverse events. In the 330 μg dose group, no subjects reported adverse events. In the 660 μg dose group, 8 subjects (66.67%) reported 16 adverse events, which were mostly gastrointestinal. There were no significant changes in the pharmacodynamic parameters except the glucagon level at day 36 in the 660 µg dose group, the 2h postprandial insulin and C peptide levels at day 36 and day 50 in the 165 μg dose group compared with baseline (- 1 day).
Conclusion: A once-weekly subcutaneous injection of 165 µg and 330 µg PEGylated exenatide is safe. No significant effects on blood glucose or pancreatic hormone levels were observed in the subjects within these dose groups. The pharmacokinetic parameters of PEGylated exenatide may be affected by immunogenicity.
Clinical trials registration: The study is registered at clinicaltrials.gov (No. NCT03062774).