Quantitative determination of pegylated consensus interferon in rhesus monkey serum using a competitive enzyme-linked immunosorbent assay

From Synthesis to Characterization of Site-Selective PEGylated Proteins

Covalent attachment of therapeutic proteins to polyethylene glycol (PEG) is widely used for the improvement of its pharmacokinetic and pharmacological properties, as well as the reduction in reactogenicity and related side effects. This technique named PEGylation has been successfully employed in several approved drugs to treat various diseases, even cancer. Some methods have been developed to obtain PEGylated proteins, both in multiple protein sites or in a selected amino acid residue. This review focuses mainly on traditional and novel examples of chemical and enzymatic methods for site-selective PEGylation, emphasizing in N-terminal PEGylation, that make it possible to obtain products with a high degree of homogeneity and preserve bioactivity. In addition, the main assay methods that can be applied for the characterization of PEGylated molecules in complex biological samples are also summarized in this paper.

A pharmacokinetic and pharmacodynamic comparison of a novel pegylated recombinant consensus interferon-α variant with peginterferon-α-2a in healthy subjects

AIMS

The aims of the study were to assess the pharmacokinetics, pharmacodynamics, safety and tolerability of a novel, pegylated recombinant human consensus interferon-α variant (PEG-IFN-SA) in healthy volunteers. A pharmacokinetic and pharmacodynamic comparison of PEG-IFN-SA and peginterferon-α-2a in healthy subjects was evaluated.

METHODS

A randomized, dose-escalating, single administration dose phase I clinical study was conducted. Thirty healthy subjects received PEG-IFN-SA as a single dose of 0.5-2.0 μg kg(-1) by subcutaneous (s.c.) injection in four parallel groups. Eight subjects received peginterferon-α-2a as a single dose of 180 μg s.c.

RESULTS

The incidence rates of adverse events for PEG-IFN-SA and peginterferon-α-2a were 29 of 30 and 7 of 8, respectively. The adverse events for PEG-IFN-SA were mild to moderate and similar to those of peginterferon-α-2a. Within 168 h after injection, the mean values of maximal concentration and area under the plasma concentration-time curve from time of dosing to 168 h [AUC(0-168h) ] for 2',5'-oligoadenylate, neopterin and β2 -microglobulin for PEG-IFN-SA at 1.5 μg kg(-1 ) s.c. were similar to or higher than those for peginterferon-α-2a at a dose of 180 μg s.c. After s.c. injection of PEG-IFN-SA at 1.5 μg kg(-1) , the mean geometric mean values of plasma half-life, time to maximal concentration, maximal concentration and AUC(0-168h) were 55.3 h, 26.9 h, 0.53 μg l(-1) and 44.0 μg l(-1)  h, respectively.

CONCLUSIONS

The tolerance, pharmacokinetic and pharmacodynamic characteristics of PEG-IFN-SA support its administration by s.c. injection as a single dose of 1.5 μg kg(-1) or at 2.0 μg kg(-1) per week.

Method for characterization of PEGylated bioproducts in biological matrixes

PEGylation of peptides and proteins has been widely used to enhance stability and reduce immunogenicity of biotherapeutics. Characterizing the degradation of these PEGylated products in biological fluids can yield essential information to support pharmacokinetic evaluations and provide clues about their in vivo properties useful for further molecular optimization. In this paper, we describe a novel and uncomplicated approach to characterize PEGylated peptides or proteins and their related degradation products in biological matrixes. The method involves direct liquid chromatography/mass spectrometry (LC/MS) analysis of animal sera containing low nanograms to low micrograms per milliliter of PEGylated product with or without an acetonitrile precipitation sample treatment. Applying the methodology to analyze the model PEGylated peptides, 20K PEGylated-Pancreatic Polypeptide analogue (PPA) and 20K PEGylated-glucagon, we elucidated the decomposition pathways occurring in animal sera. The data provided direct evidence of cleavages within the peptide backbone. The identified degradation products were unambiguously confirmed by tandem mass spectrometry with high-energy C-trap dissociation (HCD) analysis, followed with in-source fragmentation. Additional spiking studies demonstrated nearly full recovery of PEGylated products, linear detection when the spiked concentration of PEGylated product was ≤1000 ng/mL, and a low ng/mL limit of quantitation (LOQ).

Pharmacokinetics, tissue distribution, excretion, and antiviral activity of pegylated recombinant human consensus interferon-α variant in monkeys, rats and guinea pigs

The study aims to characterize the pharmacokinetic, tissue distribution, excretion, and antiviral activity properties of a novel pegylated recombinant human consensus interferon-α variant (PEG-IFN-SA) following a single subcutaneous administration to monkeys, rats and guinea pigs. Studies included: (1) pharmacokinetic properties of PEG-IFN-SA and comparison with those of non-pegylated IFN-SA in rhesus monkeys and rats; (2) tissue distribution and urinary, fecal, and biliary excretion patterns of (125)I-PEG-IFN-SA in guinea pigs; and (3) antiviral activity assessment of PEG-IFN-SA in cynomolgus monkeys. The pegylated protein exhibited improved pharmacokinetic properties compared to IFN-SA in both monkeys and rats, with a 12-fold and 15-fold increase in elimination half-life, and a 100-fold and 10-fold decrease in serum clearance, as well as a 2.5-fold and 10-fold increase in the time to reach peak serum concentration, respectively. (125)I-PEG-IFN-SA was found to be distributed to most of the tissues examined and has character of targeting special distribution, and urinary appeared to be a major route for the excretion of PEG-IFN-SA in guinea pigs. Serum sample analysis from PEG-IFN-SA-treated monkeys showed dose-dependent antiviral activity for one week. These findings demonstrate that pegylation of IFN-SA results in more desirable pharmacokinetic properties, enhanced drug exposure and sustained-efficacy of in vivo antiviral action.

Direct quantitative analysis of a 20 kDa PEGylated human calcitonin gene peptide antagonist in cynomolgus monkey serum using in-source CID and UPLC-MS/MS

PEGylation is a successful strategy to improve the pharmacokinetic and pharmaceutical properties of therapeutic peptides. However, quantitative analysis of PEGylated peptides in biomatrix by LC-MS/MS poses significant analytical challenge due to the polydispersity of the polyethylene glycol (PEG), and the multiple charge states observed for both the peptide and PEG moieties. In this report, a novel LC-MS/MS method for direct quantitative analysis of 20 kDa PEGylated CGRP[Cit, Cit] in cynomolgus monkey serum is presented. CGRP[Cit, Cit] is an investigational human calcitonin gene peptide receptor antagonist with amino acid sequence Ac -WVTH[Cit]LAGLLS[Cit]SGGVVRKNFVPT DVGPFAF-NH(2). In-source collision-induced dissociation (in-source CID) of 20 kDa PEGylated peptide was used to generate CGRP[Cit, Cit] fragment ions, among which the most abundant b(8)(+) ion was selected and measured as a surrogate for the 20 kDa PEGylated peptide. A solid phase extraction (SPE) method was used to extract the PEGylated peptides from the biomatrix prior to the UPLC-MS/MS analysis. This method achieved a lower limit of quantitation (LLOQ) of 5.00 ng/mL with a serum sample volume of 100 μL, and was linear over the calibration range of 5.00 to 500 ng/mL in cynomolgus monkey serum. Intraday and interday accuracy and precision from QC samples were within ±15%. This method was successfully applied to a pharmacokinetic study of the 20 kDa PEGylated CGRP[Cit, Cit] in cynomolgus monkeys.