Comparability of biosimilar romiplostim with originator: Protein characterization, animal pharmacodynamics and pharmacokinetics.

The results of preclinical studies of romiplostim analogue GP40141 are presented. The effect of a cell proliferation, phosphorylation of the TPO receptor and JAK2 phosphorylation were studied in the presence of romiplostim and in the presence of GP40141 in a cell line of mice (Mus musculus) lymphoblasts with stable expression of human TPO receptor 32D-hTPOR clone 63. Binding to the TPO receptor and to the neonatal Fc receptor (FcRn) was examined for both romiplostim and the developed analogue. In Sprague-Dawley rats, the dynamics of platelet count after the administration of romiplostim or GP40141 were determined. The pharmacokinetics of romiplostim and GP40141, as well as the dynamics of platelet count, were studied in cynomolgus monkeys. The serum concentrations of romiplostim were determined using a modified colorimetric enzyme-linked immunosorbent assay (ELISA). The data obtained allow us to assert the similarity of the biological action of Nplate® and GP40141.

Neuroprotective action of Cortexin, Cerebrolysin and Actovegin in acute or chronic brain ischemia in rats.

This study was the first to compare the neuroprotective activity of Cerebrolysin®, Actovegin® and Cortexin® in rodent models of acute and chronic brain ischemia. The neuroprotective action was evaluated in animals with acute (middle cerebral artery occlusion) or chronic (common carotid artery stenosis) brain ischemia models in male rats. Cortexin® (1 or 3 mg/kg/day), Cerebrolysin® (538 or 1614 mg/kg/day) and Actovegin® (200 mg/kg/day) were administered for 10 days. To assess the neurological and motor impairments, open field test, adhesive removal test, rotarod performance test and Morris water maze test were performed. Brain damage was assessed macro- and microscopically, and antioxidant system activity was measured in brain homogenates. In separate experiments in vitro binding of Cortexin® to a wide panel of receptors was assessed, and blood-brain barrier permeability of Cortexin® was assessed in mice in vivo. Cortexin® or Cerebrolysin® and, to a lesser extent, Actovegin® improved the recovery of neurological functions, reduced the severity of sensorimotor and cognitive impairments in rats. Cortexin® reduced the size of necrosis of brain tissue in acute ischemia, improved functioning of the antioxidant system and prevented the development of severe neurodegenerative changes in chronic ischemia model. Radioactively labeled Cortexin® crossed the blood-brain barrier in mice in vivo with concentrations equal to 6-8% of concentrations found in whole blood. During in vitro binding assay Cortexin® (10 µg/ml) demonstrated high or moderate binding to AMPA-receptors (80.1%), kainate receptors (73.5%), mGluR1 (49.0%), GABAA1 (44.0%) and mGluR5 (39.7%), which means that effects observed in vivo could be related on the glutamatergic and GABAergic actions of Cortexin®. Thus, Cortexin, 1 or 3 mg/kg, or Cerebrolysin®, 538 or 1614 mg/kg, were effective in models acute and chronic brain ischemia in rats. Cortexin® contains compounds acting on AMPA, kainate, mGluR1, GABAA1 and mGluR5 receptors in vitro, and readily crosses the blood-brain barrier in mice.