The pharmacokinetics of an albumin-binding Fab (AB.Fab) can be modulated as a function of affinity for albumin

Background: Anthrax toxin is the primary cause of pathology from exposure to anthrax spores. Results: Two linked single domain antibodies (VHHs), each neutralizing anthrax toxicity by different mechanisms, potently protect mice from anthrax spore challenge. Conclusion: Linked, toxin-neutralizing VHHs (VNAs) are highly effective anthrax antitoxin agents. Significance: VNAs offer excellent versatility in developing novel therapeutics for many toxin-mediated diseases.

Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

A Heterodimer of a VHH (Variable Domains of Camelid Heavy Chain-only) Antibody That Inhibits Anthrax Toxin Cell Binding Linked to a VHH Antibody That Blocks Oligomer Formation Is Highly Protective in an Anthrax Spore Challenge Model

Moayeri

Leysath

Tremblay

et al. 2015

“…PEGylated interferon ␣-2a (PegIntron, PEGASYS) and PEGylated granulocyte-colony stimulating factor (Neulasta), or are under clinical development, e.g. a PEGylated anti-TNF Fab fragment (certolizumab pegol) (9, 12) Furthermore, direct fusion to albumin or an albumin binding moiety, such as albumin-binding peptides or bacterial albuminbinding domains, was applied to improve pharmacokinetics of therapeutic proteins including interferon-␣, interleukin-2, insulin, Fab fragments, and recombinant bispecific antibody molecules (4,8,(13)(14)(15). This strategy is based on the observation that albumin has a similar half-life as IgG and also utilizes FcRn-mediated recycling processes.…”

mentioning

confidence: 99%

N-Glycosylation as Novel Strategy to Improve Pharmacokinetic Properties of Bispecific Single-chain Diabodies

Stork

Zettlitz

Müller

et al. 2008

The therapeutic efficacy of recombinant antibodies such as single-chain Fv fragments and small bispecific or bifunctional molecules is often limited by rapid elimination from the circulation because of their small size. Here, we have investigated the effects of N-glycosylation on the activity and pharmacokinetics of a small bispecific single-chain diabody (scDb CEACD3) developed for the retargeting of cytotoxic T cells to CEA-expressing tumor cells. We could show that the introduction of N-glycosylation sequons into the flanking linker and a C-terminal extension results in the production of N-glycosylated molecules after expression in transfected HEK293 cells. N-Glycosylated scDb variants possessing 3, 6, or 9 N-glycosylation sites, respectively, retained antigen binding activity and bispecificity for target and effector cells as shown in a target cell-dependent IL-2 release assay, although activity was reduced ϳ3-5-fold compared with the unmodified scDb. All N-glycosylated scDb variants exhibited a prolonged circulation time compared with scDb, leading to a 2-3-fold increase of the area under curve (AUC). In comparison, conjugation of a branched 40-kDa PEG chain increased AUC by a factor of 10.6, while a chimeric anti-CEA IgG1 molecule had the longest circulation time with a 17-fold increase in AUC. Thus, N-glycosylation complements the repertoire of strategies to modulate pharmacokinetics of small recombinant antibody molecules by an approach that moderately prolongs circulation time.Whole antibodies, especially chimeric, humanized or fully human IgG molecules, exhibit a long circulation time in the human body that can reach a half-life of 27 days (1, 2). In contrast, antibody fragments, e.g. Fab fragments, or recombinant formats, such as single-chain Fv fragments (scFv) 3 or bispecific derivatives thereof (tandem scFv, diabodies, single-chain diabodies), are rapidly cleared from circulation (2-4). This is mainly due to the small size leading to rapid renal clearance and the lack of recycling processes mediated by the neonatal Fc receptor (FcRn). Thus, repeated injections or infusions are required to maintain a therapeutically effective dose in the body (5). Several strategies to improve pharmacokinetic properties and thus dosing and therapeutic efficacy of recombinant antibodies have been developed in recent years. These strategies can be divided into: 1) those based on reducing renal clearance by increasing the apparent size of the therapeutic molecule, and 2) those that in addition implement FcRn-mediated recycling processes (6 -8).PEGylation of proteins is a well-established strategy to improve pharmacokinetic properties by increasing the molecular mass and the hydrodynamic radius (9 -11). Several PEGylated proteins are in clinical use, e.g. PEGylated interferon ␣-2a (PegIntron, PEGASYS) and PEGylated granulocyte-colony stimulating factor (Neulasta), or are under clinical development, e.g. a PEGylated anti-TNF Fab fragment (certolizumab pegol) (9, 12) Furthermore, direct fusion to albumin or an albumin bin...

“…With the advent of recombinant protein expression and efficient in vitro selection technologies, this novel class of engineered protein scaffolds presents attractive opportunities for both diagnostic and therapeutic use. If longer serum half-lives are required, this could be achieved by site-specific PEGylation (15) or by hijacking an abundant serum protein with a long half-life, like albumin or immunoglobulin G through peptide tags that bind to them to escape glomerular filtration (46,47). Knowing the recent set backs of human anti-A␤ therapies, this study opens new avenues away from antibodies toward DARPins to fight brain amyloidosis effectively.…”

Section: Discussionmentioning

confidence: 99%

Amyloid-β Peptide-specific DARPins as a Novel Class of Potential Therapeutics for Alzheimer Disease

Hanenberg

McAfoose

Kulic

et al. 2014