title: Conjugation of 10 kDa Linear PEG onto Trastuzumab Fab' Is Sufficient to Significantly Enhance Lymphatic Exposure while Preserving in Vitro Biological Activity.
abstract: The lymphatic system is a major conduit by which many diseases spread and proliferate. There is therefore increasing interest in promoting better lymphatic drug targeting. Further, antibody fragments such as Fabs have several advantages over full length monoclonal antibodies but are subject to rapid plasma clearance, which can limit the lymphatic exposure and activity of Fabs against lymph-resident diseases. This study therefore explored ideal PEGylation strategies to maximize biological activity and lymphatic exposure using trastuzumab Fab' as a model. Specifically, the Fab' was conjugated with single linear 10 or 40 kDa PEG chains at the hinge region. PEGylation led to a 3-4-fold reduction in binding affinity to HER2, but antiproliferative activity against HER2-expressing BT474 cells was preserved. Lymphatic pharmacokinetics were then examined in thoracic lymph duct cannulated rats after intravenous and subcutaneous dosing at 2 mg/kg, and the data were evaluated via population pharmacokinetic modeling. The Fab' displayed limited lymphatic exposure, but conjugation of 10 kDa PEG improved exposure by approximately 11- and 5-fold after intravenous (15% dose collected in thoracic lymph over 30 h) and subcutaneous (9%) administration, respectively. Increasing the molecular weight of the PEG to 40 kDa, however, had no significant impact on lymphatic exposure after intravenous (14%) administration and only doubled lymphatic exposure after subcutaneous administration (18%) when compared to 10 kDa PEG-Fab'. The data therefore suggests that minimal PEGylation has the potential to enhance the exposure and activity of Fab's against lymph-resident diseases, while no significant benefit is achieved with very large PEGs.
authors: Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University , 381 Royal Parade, Parkville, Victoria 3052, Australia.
authors: Linda J
authors: LJ
authors: Chan
authors: Department of Biochemistry, University of Cambridge , Sanger Building, Downing Site, Cambridge, CB2 1GA, U.K.
authors: David B
authors: DB
authors: Ascher
authors: Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University , 381 Royal Parade, Parkville, Victoria 3052, Australia.
authors: Rajbharan
authors: R
authors: Yadav
authors: Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University , 381 Royal Parade, Parkville, Victoria 3052, Australia.|Center for Pharmacometrics and Systems Pharmacology, College of Pharmacy, University of Florida , Orlando, Florida 32816, United States.
authors: Jürgen B
authors: JB
authors: Bulitta
authors: CSIRO Materials Science and Engineering , 343 Royal Parade, Parkville, Victoria 3052, Australia.
authors: Charlotte C
authors: CC
authors: Williams
authors: Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University , 381 Royal Parade, Parkville, Victoria 3052, Australia.
authors: Christopher J H
authors: CJ
authors: Porter
authors: Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University , 381 Royal Parade, Parkville, Victoria 3052, Australia.
authors: Cornelia B
authors: CB
authors: Landersdorfer
authors: Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University , 381 Royal Parade, Parkville, Victoria 3052, Australia.
authors: Lisa M
authors: LM
authors: Kaminskas
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry* / Q000276:immunology*; D045744:Cell Line, Tumor; D002850:Chromatography, Gel; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000737:chemistry* / Q000276:immunology*; D008297:Male; D011092:Polyethylene Glycols / Q000737:chemistry*; D051381:Rats; D017207:Rats, Sprague-Dawley; D000068878:Trastuzumab / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D007140:Immunoglobulin Fab Fragments; D011092:Polyethylene Glycols; D000068878:Trastuzumab
keywords: Fab; PEGylation; S-ADAPT; lymphatic; monoclonal antibody; pharmacokinetics; population modeling; trastuzumab