Quality, bioactivity study, and preclinical acute toxicity, safety pharmacology evaluation of PEGylated recombinant human endostatin (M₂ES)

Abstract

Endostar, a potent endogenous antiangiogenic factor, is wildly used in clinics. However, it was easily degraded by enzymes and rapidly cleared by the kidneys. To overcome these shortcomings, PEGylated recombinant human endostatin was developed. In this study, the purity of M2ES was evaluated by silver stain and reversed‐phase high‐performance liquid chromatography. Ultraviolet spectrum was used to examine the structural of M2ES and endostar. The bioactivity and antitumor efficacy of M2ES were evaluated using an in vitro endothelial cell migration model and athymic nude mouse xenograft model of a heterogeneous lung adenocarcinoma, respectively. A preclinical study was performed to evaluate the acute toxicity and safety pharmacology in rhesus monkeys. The purity of M2ES was more than 98%; PEG modification has no effect on endostatin structure. Compared with the control group, M2ES dramatically retards endothelial cell migration and tumor growth. After intravenous (IV) infusions of M2ES at a dose level of three and 75 mg/kg in rhesus monkeys, there was no observable serious adverse event in both acute toxicity and safety pharmacology study. On the basis of the quality and bioactivity study data of M2ES and the absence of serious side effect in rhesus monkeys, M2ES was authorized to initiate a phase I clinical trial.

Biophysical and biological characterization of PEGylated recombinant human endostatin

“…However, our results demonstrated that M 2 ES is as good as MES in terms of anti‐migration and anti‐tumour activities (Figure ), indicating that mPEG‐ALD molecule on MES protein does not influence the interaction between MES and its receptors on the membrane of endothelial cells. Besides, PEG modification substantially prolonged the circulation time of MES and effectively improved its pharmacokinetic behaviour, and no observable side‐effects were seen in both toxicity and safety pharmacology studies …”

“…Li et al reported that PEG modification substantially prolongs the circulation time of MES; the half‐life of MES (3 mg/kg) and M 2 ES (3 mg/kg) were 3.9 and 60.1 hours, respectively. In addition, M 2 ES can significantly reduce dosing frequency compared with other similar products in the market . However, there are no reports on the evaluation of physicochemical characters, bioactivity and anti‐tumour efficacy studies of M 2 ES.…”

Recent advances in the bioanalytical methods of polyethylene glycols and PEGylated pharmaceuticals

“…In fact, only the accumulation of free drugs at the target site can exert their curative effects. Excessive exposure or accumulation in healthy tissues would rather lead to toxic and side effects [51–54]. Acquiring comprehensive knowledge about the pharmacokinetics of modified drugs is vitally important to design more efficient PEGylated pharmaceuticals with good targeting property and have better control of undesired side effects [55–58].…”