751
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Ikeda Y, Taira K. Ligand-Targeted Delivery of Therapeutic siRNA. Pharm Res 2006; 23:1631-40. [PMID: 16850274 DOI: 10.1007/s11095-006-9001-x] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2005] [Accepted: 03/06/2006] [Indexed: 10/24/2022]
Abstract
RNA interference (RNAi) is a post-transcriptional gene-silencing phenomenon that is triggered by double-stranded RNA (dsRNA). Since many diseases are associated with the inappropriate production of specific proteins, attempts are being made to exploit RNAi in a clinical settings. However, before RNAi can be exploited as therapeutically, several obstacles must be overcome. For example, small interfering RNA (siRNA) is unstable in the blood stream so any effects of injected siRNA are only transient. Accordingly, methods must be developed to prolong its activity. Furthermore, the efficient and safe delivery of siRNA into target tissues and cells is critical for successful therapy. Any useful delivery method should be designed to target siRNA to specific cells and to promote gene-silencing activity once the siRNA is inside the cells. Recent chemical modifications of siRNA have overcome problems associated with the instability of siRNA, and various ligands, including glycosylated molecules, peptides, proteins, antibodies and engineered antibody fragments, appear to be very useful or have considerable potential for the targeted delivery of siRNA. The use of such ligands improves the efficiency, specificity and, as a consequence, the safety of the corresponding delivery systems.
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Affiliation(s)
- Yutaka Ikeda
- Gene Function Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Central 4, 1-1-1 Higashi, 305-8562 Tsukuba Science City, Japan
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752
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Ferl GZ, Kenanova V, Wu AM, DiStefano JJ. A two-tiered physiologically based model for dually labeled single-chain Fv-Fc antibody fragments. Mol Cancer Ther 2006; 5:1550-8. [PMID: 16818514 DOI: 10.1158/1535-7163.mct-06-0072] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Monoclonal antibodies (mAb) are being used at an increasing rate in the treatment of cancer, with current efforts focused on developing engineered antibodies that exhibit optimal biodistribution profiles for imaging and/or radioimmunotherapy. We recently developed the single-chain Fv-Fc (scFv-Fc) mAb, which consists of a single-chain antibody Fv fragment (light-chain and heavy-chain variable domains) coupled to the IgG1 Fc region. Point mutations that attenuate binding affinity to FcRn were introduced into the Fc region of the wild-type scFv-Fc mAb, resulting in several new antibodies, each with a different half-life. Here, we describe the construction of a two-tiered physiologically based pharmacokinetic model capable of simulating the apparent biodistribution of both (111)In- and (125)I-labeled scFv-Fc mAbs, where (111)In-labeled metabolites from degraded (111)In-labeled mAbs tend to become trapped within the lysosomal compartment, whereas free (125)I from degraded (125)I-labeled mAbs is quickly eliminated via the urinary pathway. The different concentration-time profiles of (111)In- and (125)I-labeled mAbs permits estimation of the degradation capacity of each organ and elucidates the dependence of cumulative degradation in liver, muscle, and skin on FcRn affinity and tumor mass. Liver is estimated to account for approximately 50% of all degraded mAb when tumor is small (approximately 0.1 g) and drops to about 35% when tumor mass is larger (approximately 0.3 g). mAb degradation in residual carcass (primarily skin and muscle) decreases from approximately 45% to 16% as FcRn affinity of the three mAb variants under consideration increases. In addition, elimination of a small amount of mAb in the kidneys is shown to be required for a successful fit of model to data.
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Affiliation(s)
- Gregory Z Ferl
- Department of Computer Science, University of California, Los Angeles, USA.
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753
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Chatterjee M, Chakraborty T, Tassone P. Multiple myeloma: monoclonal antibodies-based immunotherapeutic strategies and targeted radiotherapy. Eur J Cancer 2006; 42:1640-52. [PMID: 16797969 DOI: 10.1016/j.ejca.2006.02.016] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2006] [Accepted: 02/22/2006] [Indexed: 02/08/2023]
Abstract
Multiple myeloma (MM) is an incurable B-cell malignancy of terminally differentiated plasma cells. Besides conventional treatments, several targeted therapies are emerging for MM. We review recent developments in monoclonal antibodies (MoAbs) and (radio)immunoconjugates-based targeted immunotherapeutic (serotherapies) strategies, as well as skeletal targeted radiotherapy (STR) in MM. MoAbs-based strategies include the targeting of cytokines and their receptors as well as toxins, drugs or radionuclide delivery to MM cells. Both targeted radioimmunotherapy (RIT) and STR have proved efficient in the treatment of radiosensitive tumours. We conclude that there is a need for more mechanistic investigations of drug action to identify novel therapeutic targets in myeloma cells, as well as in the bone marrow microenvironment.
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Affiliation(s)
- Malay Chatterjee
- Department of Pharmaceutical Technology, Division of Biochemistry, Jadavpur University, Calcutta, West-Bengal 700 032, India.
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754
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Bakhtiar R, Guan Z. Electron Capture Dissociation Mass Spectrometry in Characterization of Peptides and Proteins. Biotechnol Lett 2006; 28:1047-59. [PMID: 16794768 DOI: 10.1007/s10529-006-9065-z] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2006] [Accepted: 03/29/2006] [Indexed: 10/24/2022]
Abstract
Electron capture dissociation (ECD) represents one of the most recent and significant advancements in tandem mass spectrometry (MS/MS) for the identification and characterization of polypeptides. In comparison with the conventional fragmentation techniques, such as collisionally activated dissociation (CAD), ECD provides more extensive sequence fragments, while allowing the labile modifications to remain intact during backbone fragmentation--an important attribute for characterizing post-translational modifications. Herein, we present a brief overview of the ECD technique as well as selected applications in characterization of peptides and proteins. Case studies including characterization and localization of amino acid glycosylation, methionine oxidation, acylation, and "top-down" protein mass spectrometry using ECD will be presented. A recent technique, coined as electron transfer dissociation (ETD), will be also discussed briefly.
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Affiliation(s)
- Ray Bakhtiar
- Merck Research Laboratories, Rahway, NJ 07065, USA.
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755
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Ashcroft JM, Tsyboulski DA, Hartman KB, Zakharian TY, Marks JW, Weisman RB, Rosenblum MG, Wilson LJ. Fullerene (C60) immunoconjugates: interaction of water-soluble C60 derivatives with the murine anti-gp240 melanoma antibody. Chem Commun (Camb) 2006:3004-6. [PMID: 16832518 DOI: 10.1039/b601717g] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The first fullerene (C60) immunoconjugates have been prepared and characterized as an initial step toward the development of fullerene immunotherapy (FIT).
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Affiliation(s)
- Jared M Ashcroft
- Department of Chemistry, Smalley Institute for Nanoscale Science and Technology, and the Center for Biological and Environmental Nanotechnology, MS 60, Rice University, Houston, Texas 77005, USA
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756
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Erickson HK, Park PU, Widdison WC, Kovtun YV, Garrett LM, Hoffman K, Lutz RJ, Goldmacher VS, Blättler WA. Antibody-maytansinoid conjugates are activated in targeted cancer cells by lysosomal degradation and linker-dependent intracellular processing. Cancer Res 2006; 66:4426-33. [PMID: 16618769 DOI: 10.1158/0008-5472.can-05-4489] [Citation(s) in RCA: 414] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Antibody-drug conjugates are targeted anticancer agents consisting of a cytotoxic drug covalently linked to a monoclonal antibody for tumor antigen-specific activity. Once bound to the target cell-surface antigen, the conjugate must be processed to release an active form of the drug, which can reach its intracellular target. Here, we used both biological and biochemical methods to better define this process for antibody-maytansinoid conjugates. In particular, we examined the metabolic fate in cells of huC242-maytansinoid conjugates containing either a disulfide linker (huC242-SPDB-DM4) or a thioether linker (huC242-SMCC-DM1). Using cell cycle analysis combined with lysosomal inhibitors, we showed that lysosomal processing is required for the activity of antibody-maytansinoid conjugates, irrespective of the linker. We also identified and characterized the released maytansinoid molecules from these conjugates, and measured their rate of release compared with the kinetics of cell cycle arrest. Both conjugates are efficiently degraded in lysosomes to yield metabolites consisting of the intact maytansinoid drug and linker attached to lysine. The lysine adduct is the sole metabolite from the thioether-linked conjugate. However, the lysine metabolite generated from the disulfide-linked conjugate is reduced and S-methylated to yield the lipophilic and potently cytotoxic metabolite, S-methyl-DM4. These findings provide insight into the mechanism of action of antibody-maytansinoid conjugates in general, and more specifically, identify a biochemical mechanism that may account for the significantly enhanced antitumor efficacy observed with disulfide-linked conjugates.
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757
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758
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Clynes R. Antitumor Antibodies in the Treatment of Cancer: Fc Receptors Link Opsonic Antibody with Cellular Immunity. Hematol Oncol Clin North Am 2006; 20:585-612. [PMID: 16762726 DOI: 10.1016/j.hoc.2006.02.010] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Engineered antibody therapeutics have provided new treatment options in cancer. Genetic evidence in man and in the mouse suggests that Fc receptor (FcR) engagement contributes mechanistically to the therapeutic activity of naked antibodies. Preferential activation of activating FcRs and limited engagement of inhibitory FcRs enhance tumor responses in mouse models. Thus, engineered Fc domains with favorable affinities for specific FcR types may prove to be clinically superior.
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Affiliation(s)
- Raphael Clynes
- Department of Medicine, Columbia University, College of Physicians and Surgeons, New York, NY 10032, USA.
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759
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Guo YC, Zhou YF, Zhang XE, Zhang ZP, Qiao YM, Bi LJ, Wen JK, Liang MF, Zhang JB. Phage display mediated immuno-PCR. Nucleic Acids Res 2006; 34:e62. [PMID: 16682441 PMCID: PMC1458518 DOI: 10.1093/nar/gkl260] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Immuno-PCR (IPCR) is a powerful detection technology in immunological study and clinical diagnosis due to its ultrasensitivity. Here we introduce a new strategy termed phage display mediated immuno-PCR (PD-IPCR). Instead of utilization of monoclonal antibody (mAb) and chemically bond DNA that required in the conventional IPCR, a recombinant phage particle is applied as a ready reagent for IPCR experiment. The surface displayed single chain variable fragment (scFv) and phage DNA themselves can directly serve as detection antibody and PCR template, respectively. The aim of the design is to overcome shortcoming of low detection sensitivity of scFv so as to largely facilitate the real application of scFv in immunoassay. The idea has been demonstrated by applying hantaan virus nucleocapsid protein (NP) and prion protein (PrP) as detection targets in three experimental protocols (indirect, sandwich and real-time PD-IPCR assays). The detection sensitivity was increased 1000- to 10 000-folds compared with conventional enzyme-linked immunosorbent assays (ELISAs). This proof-of-concept study may serve as a new model to develop an easy to operate, low cost and ultrasensitive immunoassay method for broad applications.
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Affiliation(s)
- Yong-Chao Guo
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of SciencesWuhan 430071, China
- Graduate School, Chinese Academy of SciencesBeijing 100039, China
| | - Ya-Feng Zhou
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of SciencesWuhan 430071, China
| | - Xian-En Zhang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of SciencesWuhan 430071, China
- To whom correspondence should be addressed. Tel: +86 10 58881508; Fax: +86 27 87199;
| | - Zhi-Ping Zhang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of SciencesWuhan 430071, China
| | - Yan-Mei Qiao
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of SciencesWuhan 430071, China
- Graduate School, Chinese Academy of SciencesBeijing 100039, China
| | - Li-Jun Bi
- State Key Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of SciencesBeijing 100101, China
| | - Ji-Kai Wen
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of SciencesWuhan 430071, China
| | - Mi-Fang Liang
- Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and PreventionBeijing 100052, China
| | - Ji-Bin Zhang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of SciencesWuhan 430071, China
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760
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Kovtun YV, Audette CA, Ye Y, Xie H, Ruberti MF, Phinney SJ, Leece BA, Chittenden T, Blättler WA, Goldmacher VS. Antibody-drug conjugates designed to eradicate tumors with homogeneous and heterogeneous expression of the target antigen. Cancer Res 2006; 66:3214-21. [PMID: 16540673 DOI: 10.1158/0008-5472.can-05-3973] [Citation(s) in RCA: 310] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Conjugates of the anti-CanAg humanized monoclonal antibody huC242 with the microtubule-formation inhibitor DM1 (a maytansinoid), or with the DNA alkylator DC1 (a CC1065 analogue), have been evaluated for their ability to eradicate mixed cell populations formed from CanAg-positive and CanAg-negative cells in culture and in xenograft tumors in mice. We found that in culture, conjugates of either drug killed not only the target antigen-positive cells but also the neighboring antigen-negative cells. Furthermore, we showed that, in vivo, these conjugates were effective in eradicating tumors containing both antigen-positive and antigen-negative cells. The presence of antigen-positive cells was required for this killing of bystander cells. This target cell-activated killing of bystander cells was dependent on the nature of the linker between the antibody and the drug. Conjugates linked via a reducible disulfide bond were capable of exerting the bystander effect whereas equally potent conjugates linked via a nonreducible thioether bond were not. Our data offer a rationale for developing optimally constructed antibody-drug conjugates for treating tumors that express the target antigen either in a homogeneous or heterogeneous manner.
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761
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Rossi EA, Goldenberg DM, Cardillo TM, McBride WJ, Sharkey RM, Chang CH. Stably tethered multifunctional structures of defined composition made by the dock and lock method for use in cancer targeting. Proc Natl Acad Sci U S A 2006; 103:6841-6. [PMID: 16636283 PMCID: PMC1447525 DOI: 10.1073/pnas.0600982103] [Citation(s) in RCA: 176] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We describe a platform technology, termed the dock and lock method, which uses a natural binding between the regulatory subunits of cAMP-dependent protein kinase and the anchoring domains of A kinase anchor proteins for general application in constructing bioactive conjugates of different protein and nonprotein molecules from modular subunits on demand. This approach could allow quantitative and site-specific coupling of many different biological substances for diverse medical applications. The dock and lock method is validated herein by producing bispecific, trivalent-binding complexes composed of three stably linked Fab fragments capable of selective delivery of radiotracers to human cancer xenografts, resulting in rapid, significantly improved cancer targeting and imaging, providing tumor/blood ratios from 66 +/- 5 at 1 h to 395 +/- 26 at 24 h.
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Affiliation(s)
| | - David M. Goldenberg
- *IBC Pharmaceuticals, Inc., and
- Immunomedics, Inc., 300 American Road, Morris Plains, NJ 07950; and
- Garden State Cancer Center, Center for Molecular Medicine and Immunology, 520 Belleville Avenue, Belleville, NJ 07109
- To whom correspondence should be addressed. E-mail:
| | | | | | - Robert M. Sharkey
- Garden State Cancer Center, Center for Molecular Medicine and Immunology, 520 Belleville Avenue, Belleville, NJ 07109
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762
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Abstract
Antibodies constitute the most rapidly growing class of human therapeutics and the second largest class of drugs after vaccines. The generation of potent antibody therapeutics, which I review here, is an iterative design process that involves the generation and optimization of antibodies to improve their clinical potential.
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Affiliation(s)
- Paul J Carter
- Department of Antibody Technologies, Seattle Genetics Incorporated, 21823 30th Drive South East, Bothell, Washington 98021, USA.
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763
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Targeted Therapy in Oncology. Med J Armed Forces India 2006; 62:169-73. [PMID: 27407885 DOI: 10.1016/s0377-1237(06)80063-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2006] [Accepted: 03/16/2006] [Indexed: 01/14/2023] Open
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764
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Schrama D, Reisfeld RA, Becker JC. Antibody targeted drugs as cancer therapeutics. Nat Rev Drug Discov 2006; 5:147-59. [PMID: 16424916 DOI: 10.1038/nrd1957] [Citation(s) in RCA: 545] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Treatment of cancer is a double-edged sword: it should be as aggressive as possible to completely destroy the tumour, but it is precisely this aggressiveness which often causes severe side effects - a reason why some promising therapeutics can not be applied systemically. In addition, therapeutics such as cytokines that physiologically function in a para- or autocrine fashion require a locally enhanced level to exert their effect appropriately. An elegant way to accumulate therapeutic agents at the tumour site is their conjugation/fusion to tumour-specific antibodies. Here, we discuss recent preclinical and clinical data for antibody-drug conjugates and fusion proteins with a special focus on drug components that exert their antitumour effects through normal biological processes.
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Affiliation(s)
- David Schrama
- University of Wuerzburg, Dermatology, 97080 Wuerzburg, Germany
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765
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Abstract
Therapeutic antibodies are well established as an important class of drugs in modern medicine. The exquisite specificity and affinity for a specific target offered by antibodies has also encouraged their development as delivery vehicles for agents such as radionuclides to target tissues, for radioimmunoimaging and radioimmunotherapy. Specifically, in nuclear medicine, radionuclide-conjugated antibody molecules make it possible to image diseased loci with greater sensitivity than other imaging modalities such as magnetic resonance imaging. Furthermore, two radionuclide-conjugated antibodies have recently been approved for the therapy of non-Hodgkin's lymphoma. However, optimal implementation of antibodies has been limited by the extended circulation persistence that is characteristic of native antibodies, which is responsible for increased background activity in radioimmunoimaging applications and dose-related normal organ toxicities in radioimmunotherapy. In this article the current status of radiolabelled intact antibodies is reviewed, focusing on strategies to improve their pharmacokinetic properties to suit a desired application. Examples from the literature that represent different approaches to accomplishing this task in terms of their successes as well as limitations, and perspectives for the future are discussed.
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Affiliation(s)
- Vania Kenanova
- Crump Institute for Molecular Imaging, Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, University of California-Los Angeles, 700 Westwood Plaza, Los Angeles, CA 90095, USA
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766
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Abstract
The most significant recent advances in the application of monoclonal antibodies (mAbs) to oncology have been the introduction and approval of bevacizumab (Avastin), an anti-vascular endothelial growth factor antibody, and of cetuximab (Erbitux), an anti-epidermal growth factor antibody. In combination with standard chemotherapy regimens, bevacizumab significantly prolongs the survival of patients with metastatic cancers of the colorectum, breast and lung. Cetuximab, used alone or with salvage chemotherapy, produces clinically meaningful anti-tumor responses in patients with chemotherapy-refractory cancers of the colon and rectum. In addition, the anti-HER2/neu antibody trastuzumab (Herceptin), in combination with standard adjuvant chemotherapy, has been shown to reduce relapses and prolong disease-free and overall survival in high-risk patients after definitive local therapy for breast cancer. These exciting recent results provide optimism for the development of mAbs that bind novel targets, exploit novel mechanisms of action or possess improved tumor targeting. Progress in the clinical use of radioimmunoconjugates remains hindered by complexity of administration, toxicity concerns and insufficiently selective tumor targeting.
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Affiliation(s)
- Gregory P Adams
- Department of Medical Oncology, Fox Chase Cancer Center, 333 Cottman Avenue, Philadelphia, Pennsylvania 19111, USA
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