ReviewPharmacokinetics and biodistribution of genetically engineered antibodies
Introduction
Monoclonal antibodies (mAbs) are providing an insight into the biology of several malignancies. Some tumor antigens, identified by mAbs, are being used as reliable markers of disease activity. mAbs against tumor-associated antigens (TAAs) are also being used for therapy, either alone as immunologic mediators of cytotoxicity, by blocking receptors or conjugated to a drug, toxin or radionuclide. The efficacy of these conjugated antibodies is limited by their ability to reach their target tumor in adequate quantities without delivering a toxic dose to other tissues. In addition, most of the mAbs are murine in nature and systemic administration of these intact antibodies can lead to the development of a human anti-mouse immunoglobulin antibody (HAMA) response. The HAMA response is usually directed against the constant regions of the immunoglobulin (Ig), but anti-idiotypic responses have also been detected. The HAMA response can reduce the efficacy of subsequent treatment by removing the circulating IgG molecules or antibody fragments, and possibly by altering the pharmacokinetic properties of Fvs.
In the past decade, a new wave of humanized antibodies and antibody fragments has emerged called ‘genetically engineered antibodies’ 1., 2•.. Molecular cloning and the expression of the variable region genes of Ig have greatly facilitated the generation of engineered antibodies. Efforts to minimize the size of proteins capable of recognizing antigens with high-affinity binding have led to the development of Fv fragments of Ig. Their smaller size (25 kDa) makes them potentially more useful than a whole antibody for clinical applications. A single-chain variable antibody fragment (scFv) recombinant protein for a given mAb can be prepared by connecting the genes encoding the heavy chain and light chain variable regions at the DNA level with an appropriate oligonucleotide. The resulting translation product forms a single polypeptide chain with a linker bridging the two variable domains.
This review describes how innovative technology has enabled researchers to engineer intact and small-fragment antibodies with the desired pharmacokinetics and biodistribution properties. Engineered antibodies currently represent over 30% of biological proteins under various clinical trials for cancer diagnosis and therapy [3••].
Section snippets
Engineering of intact antibodies
Several novel strategies have been employed to generate antibody constructs (Fig. 1) with altered pharmacology. Igs have long blood clearance half-lives (T1/2) of up to 3 weeks for major IgG subclasses in human and 5 days in mice. Slow blood clearance greatly reduces the objective of obtaining a high tumor/normal tissue localization ratio as it increases the background in normal tissue (resulting in toxicity) due to its presence in the blood. If clearance is too fast, however, mAbs will not
Small size antibody fragments
When scFv molecules are compared with intact mAbs or more conventional enzymatically derived F(ab′)2 and Fab′ fragments, they offer several advantages as carriers for the selective delivery of radionuclides to tumors. First, the rate of clearance of scFv from the blood pool and normal tissues has been shown to be much more rapid than that seen with intact IgG, F(ab′)2 or Fab′ fragments. This offers the possibility of earlier imaging times and a reduction of the radiation dose to normal tissues
Conclusions
Based on the desired pharmacokinetics, biodistribution and immunogenicity, it seems that genetically engineered antibodies provide new promises for targeted therapy and diagnosis. Multivalent scFvs exhibit a gain in avidity over monovalent scFvs with an improved biological half-life. For RIT applications, these engineered constructs are presenting a therapeutic advantage over parent antibodies. By contrast, due to faster clearance, the monovalent scFvs may be important for clinical imaging
Acknowledgements
Authors on this review article are being supported by grants from the United States Department of Energy (DE-FG02-95ER62024) and the National Institutes of Health (RO1 CA78590 and P50 CA72712). Ellen Graham, administrative assistant, Eppley Institute, University of Nebraska Medical Center, is greatly acknowledged for her editorial assistance.
References and recommended reading
Papers of particular interest, published within the annual period of review, have been highlighted as:
• of special interest
•• of outstanding interest
References (36)
- et al.
Development of a minimally immunogenic variant of humanized anti-carcinoma monoclonal antibody CC49
Crit Rev Oncol Hematol
(2001) - et al.
FcRn: the MHC class I-related receptor that is more than an IgG transporter
Immunol Today
(1997) - et al.
Charge-modified single chain antibody constructs of monoclonal antibody CC49: generation, characterization, pharmacokinetics, and biodistribution analysis
Nucl Med Biol
(1999) - et al.
Tumor targeting of mono-, di-, and tetravalent anti-p185(HER-2) miniantibodies multimerized by self-associating peptides
J Biol Chem
(2001) - et al.
High avidity scFv multimers; diabodies and triabodies
J Immunol Methods
(1999) - et al.
Effects of genetic engineering on the pharmacokinetics of antibodies
Q J Nucl Med
(1999) - et al.
Engineered antibodies take center stage
Hum Antibodies
(2001) Recombinant antibodies: a novel approach to cancer diagnosis and therapy
Expert Opin Investig Drugs
(2000)- et al.
Pharmacokinetics and biodistribution of genetically-engineered antibodies
Q J Nucl Med
(1998) - et al.
Monoclonal antibodies to target epidermal growth factor receptor-positive tumors: a new paradigm for cancer therapy
Cancer
(2002)
IMC-C225, an anti-epidermal growth factor receptor monoclonal antibody, for treatment of head and neck cancer
Expert Opin Biol Ther
Generation, characterization, and in vivo studies of humanized anticarcinoma antibody CC49
Hybridoma
Generation and characterization of a single gene-encoded single-chain-tetravalent antitumor antibody
Clin Cancer Res
Differences in promiscuity for antibody–FcRn interactions across species: implications for therapeutic antibodies
Int Immunol
The effects of domain deletion, glycosylation, and long IgG3 hinge on the biodistribution and serum stability properties of a humanized IgG1 immunoglobulin, hLL2, and its fragments
Clin Cancer Res
Serum half-life and tumor localization of a chimeric antibody deleted of the CH2 domain and directed against the disialoganglioside GD2
Proc Natl Acad Sci USA
A CDR-grafted (humanized) domain-deleted antitumor antibody
Cancer Biother Radiopharm
Single amino acid substitution in the Fc region of chimeric TNT-3 antibody accelerates clearance and improves immunoscintigraphy of solid tumors
J Nucl Med
Cited by (170)
Production of novel recombinant anti-EpCAM antibody as targeted therapy for breast cancer
2023, International ImmunopharmacologyBiosynthesis and Genetic Incorporation of 3,4-Dihydroxy-L-Phenylalanine into Proteins in Escherichia coli
2022, Journal of Molecular BiologyCitation Excerpt :Trastuzumab targets the human epidermal growth factor 2 (HER2) receptor that is highly expressed on a variety of cancer cells, and has been approved by the FDA for treatment of cancer.65 The ScFv fragment of Trastuzumab is of special interest because of its enhanced tissue and tumor penetration and its ease of preparation from bacterial cells.66,67 To determine if DOPA-containing ScFv can be prepared using DOPA autonomous cells, the ScFv sequence with an amber stop codon at position 113 was substituted in place of the sfGFP gene sequence within pET22b-T5-sfGFP*-MmH-MH4R, yielding pET22b-T5-ScFv*-MmH-MH4R.30
Engineering of single-domain antibodies for next-generation snakebite antivenoms
2021, International Journal of Biological MacromoleculesPharmacokinetic and pharmacodynamic considerations in the development of biotechnology products and large molecules
2021, Atkinson's Principles of Clinical PharmacologyAnti-tumor effect of single-chain antibody to Reg3a in colorectal cancer
2020, Experimental Cell ResearchDesign and assessment of an active anti-epidermal growth factor receptor (EGFR) single chain variable fragment (ScFv) with improved solubility
2019, Biochemical and Biophysical Research CommunicationsCitation Excerpt :Mutations in the EGFR gene have been associated with several types of tumors [1], and therapeutic Anti-EGFR monoclonal antibodies (mAbs) such as Panitumumab and Cetuximab have been developed [2,3]. Current mAbs have limitations such as their low tumor penetration, slow blood clearance rate and especially, and their high production cost [4,5]. Recombinant antibody fragments such as ScFv [4] and VHH [6] are much smaller than the full-length mAbs and are expected to address these issues, and additionally to have a rapid tumor penetration rate [7].