Quality, bioactivity study, and preclinical acute toxicity, safety pharmacology evaluation of PEGylated recombinant human endostatin (M 2 ES).

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 M2 ES was evaluated by silver stain and reversed-phase high-performance liquid chromatography. Ultraviolet spectrum was used to examine the structural of M2 ES and endostar. The bioactivity and antitumor efficacy of M2 ES 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 M2 ES was more than 98%; PEG modification has no effect on endostatin structure. Compared with the control group, M2 ES dramatically retards endothelial cell migration and tumor growth. After intravenous (IV) infusions of M2 ES 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 M2 ES and the absence of serious side effect in rhesus monkeys, M2 ES was authorized to initiate a phase I clinical trial.