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.

PKPD Modeling and Simulations to Support Biosimilar Development of Biphasic Insulin Aspart 30.

This paper presents an analysis of data from a comparative study of biosimilarity in terms of pharmacokinetics and pharmacodynamics in healthy volunteers using a hyperinsulinemic euglycemic clamp for reference and test biphasic insulin aspart 30 (BIAsp 30). As a result of the study, one of the secondary pharmacodynamic (PD) endpoints did not satisfy the classical criterion of 80%-125% (the lower limit for PD parameter area under the glucose infusion rate-time curve [ AUC GIR 0 - t ${\rm{AUC}}_{{\rm{GIR}}_{0 - {\rm{t}}}}$ ] turned out to be 79.5%). The main hypothesis explaining this result is that the sample size is insufficient to conduct a PD test with 90% statistical power, since the sample size has been calculated based on the coefficient of variation (CV) of pharmacokinetic (PK) parameters. To test this hypothesis, population PKPD (popPKPD) modeling and subsequent simulations of the required number of PD profiles were used. Two popPKPD models were constructed (a one-compartment double simultaneous absorption model for PK and an effect compartment Emax model for PD) to describe the PKPD data of reference and test insulins. As a result, using real data along with model-based simulation data, a biosimilarity test for PD was performed, and the lower limit for AUC GIR 0 - t ${\rm{AUC}}_{{\rm{GIR}}_{0 - {\rm{t}}}}$ became 82.6%, while the CV decreased from 31.7% to 24.1%. Thus, popPKPD modeling and simulations have been shown to be effective in interpreting and supporting the results of clinical biosimilarity trials.

Clinical Pharmacology of Insulin Aspart Biosimilar GP40071: Pharmacokinetic/Pharmacodynamic Comparability in Hyperinsulinemic Euglycemic Clamp Procedure.

Insulin aspart is a short-acting insulin analogue that is used to control postprandial glycemia levels in diabetic patients. The aim of this clinical trial was to compare the pharmacokinetics and pharmacodynamics of GP40071 (GP-Asp) and NovoRapid Penfill (Novo-Asp) in a hyperinsulinemic euglycemic clamp (HEC). This trial was conducted as a part of a GP40071 biosimilar clinical development program. This was a phase I randomized, double-blind, two-period crossover study. Twenty-six healthy male volunteers aged 18 to 45 years who met the inclusion criteria underwent the procedure of an HEC following a single subcutaneous injection of 0.3 IU/kg of either GP-Asp or Novo-Asp into the abdomen. After doses, plasma glucose levels were monitored every 5 minutes for 8 hours. The adjustment of the glucose infusion rate (GIR) was based on the blood glucose measurements. The GIR values were used to evaluate the PD profiles of the studied drugs. Regular blood sampling was performed during the study to obtain sufficient pharmacokinetic data. The 90% confidence intervals for the geometric mean ratios of the pharmacokinetic (AUCins.0-t , Cins.max ) and pharmacodynamic (GIRmax , AUCGIR0-t ) parameters of GP-Asp were within the 80%-125% comparability limits. The safety profiles of the drugs were also comparable. Bioequivalence, similar PD, and safety of GP-Asp and Novo-Asp were demonstrated.

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.