Abstract
Characterization of pharmacokinetic (PK) properties and target tissue distribution of therapeutic fusion proteins (TFPs) are critical in supporting in vivo efficacy. We evaluated the pharmacokinetic profile of an investigational TFP consisting of human immunoglobulin G4 fused to the modified interferon alpha by orthogonal bioanalytical assays and applied minimal physiologically based pharmacokinetic (PBPK) modeling to characterize the TFP pharmacokinetics in mouse. The conventional ligand binding assay (LBA), immunocapture-liquid chromatography/tandem mass spectrometry (IC-LC/MS) detecting the human IgG4 peptide or the interferon alpha peptide were developed to measure the TFP concentrations in mouse plasma and tumor. The minimal PBPK model incorporated a tumor compartment model was used for data fitting. The plasma clearance measured by LBA and IC-LC/MS was comparable in the range of 0.5–0.6 mL/h/kg. However, the tumor exposure measured by the generic human IgG4 IC-LC/MS was significantly underestimated compared with the interferon alpha specific IC-LC/MS and LBA. Furthermore, the minimal PBPK model simultaneously captured the relationship between plasma and tissue exposure. We proposed the streamlined practical strategy to characterize the plasma exposure and tumor distribution of a TFP by both LBA and IC-LC/MS. The minimal PBPK modeling was established for better understanding of pharmacokinetic profile of investigational TFPs in the biotherapeutic discovery.
Highlights
The advancement of genetic translation and recombinant technologies have enabled to develop fusion proteins targeting multiple targets to achieve better efficacy, safety, and pharmacokinetic profile such as extended half-life, targeted distribution, and enhanced pharmacologic activity
We aimed to establish both generic/specific IC-LC/MS and Ligand binding assay (LBA)-based assays to elucidate the pharmacokinetic profile in plasma and tissue of the therapeutic fusion proteins (TFPs) comprising of human IgG4 targeting cell surface CD38 fused to a modified form of human interferon alpha
A generic human fragment crystallizable (Fc) assay may be used for the intact TFP, the assay cannot differentiate the intact molecule and any circulating variant forms, e.g., catabolites chipped off the therapeutic protein domain in the molecule
Summary
The advancement of genetic translation and recombinant technologies have enabled to develop fusion proteins targeting multiple targets to achieve better efficacy, safety, and pharmacokinetic profile such as extended half-life, targeted distribution, and enhanced pharmacologic activity. A common approach of therapeutic proteins is to fuse a human IgG fragment crystallizable (Fc) region, which is responsible for the neonatal Fc receptor (FcRn) binding by antibody recycling for a longer half-life [1]. The primary determinants of TFPs disposition are renal elimination, target mediated drug disposition, FcRn mediated recycling, anti-drug antibody clearance, catabolism and tissue distribution followed by catabolism within tissue. The exposure at the site of action, i.e., in the tumor tissue where the therapeutic target antigen expresses is one of the significant interests for evaluating anti-cancer biotherapeutics [2]. The quantification of TFPs in tissues has unique challenges such as efficient extraction from tissues and the requirement of high sensitivity for detection since tissue concentrations
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
