Bi-specific T-cell engager
Bi-specific T-cell engagers (BiTEs) are a class of artificial bispecific monoclonal antibodies that are investigated for the use as anti-cancer drugs. They direct a host's immune system, more specifically the T cells' cytotoxic activity, against cancer cells. BiTE is a registered trademark of Micromet AG.
BiTEs are fusion proteins consisting of two single-chain variable fragments (scFvs) of different antibodies, or amino acid sequences from four different genes, on a single peptide chain of about 55 kilodaltons. One of the scFvs binds to T cells via the CD3 receptor, and the other to a tumor cell via a tumor specific molecule.[1][2]
Mechanism of action
Like other bispecific antibodies, and unlike ordinary monoclonal antibodies, BiTEs form a link between T cells and tumor cells. This causes T cells to exert cytotoxic activity on tumor cells by producing proteins like perforin and granzymes, independently of the presence of MHC I or co-stimulatory molecules. These proteins enter tumor cells and initiate the cell's apoptosis.[1][3]
This action mimics physiological processes observed during T cell attacks against tumor cells.[3]
Examples
Clinical trials
The following BiTEs are in clinical trials as of July 2010[update]:
Further research
Utilizing the same technology, melanoma (with MCSP specific BiTEs) and acute myeloid leukemia (with CD33 specific BiTEs) can be targeted.[7] Research in this area is currently ongoing. Another avenue for novel anti-cancer therapies is re-engineering some of the currently used conventional antibodies like trastuzumab (targeting HER2/neu), cetuximab and panitumumab (both targeting the EGF receptor), using the BiTE approach.[8] BiTEs against CD66e and EphA2 are being developed as well.[9]
References
- ^ a b c Helwick, Caroline (1 June 2008). "Novel BiTE antibody mediates contact between T cells and cancer cells". Oncology NEWS International 17 (6). http://www.cancernetwork.com/display/article/10165/1165525.
- ^ Rüttinger, D.; Zugmaier, G.; Nagorsen, D.; Reinhardt, C.; Baeuerle, P. A. (2008). "BiTE-Antikörper: Durch Bispezifität T-Lymphozyten gegen Tumorzellen richten [BiTE antibodies: Directing T lymphocytes against tumor cells by bispecifity]" (in German). Journal Onkologie (4). http://www.journalonko.de/aktuellview.php?id=1656.
- ^ a b "BiTE Antibody Platform". Micromet Inc. http://www.micromet.de/index.php?id=67.
- ^ Nagorsen, D.; Bargou, R.; Rüttinger, D.; Kufer, P.; Baeuerle, P. A.; Zugmaier, G. (2009). "Immunotherapy of lymphoma and leukemia with T-cell engaging BiTE antibody blinatumomab". Leukemia & Lymphoma 50 (6): 886–891. doi:10.1080/10428190902943077. PMID 19455460. edit
- ^ ClinicalTrials.gov NCT00635596 Phase I Study of MT110 in Colorectal Cancer (CRC), Gastrointestinal (GI) and Lung Cancer (MT110-101)
- ^ Amann, M.; DÁrgouges, S.; Lorenczewski, G.; Brischwein, K.; Kischel, R.; Lutterbuese, R.; Mangold, S.; Rau, D. et al. (2009). "Antitumor Activity of an EpCAM/CD3-bispecific BiTE Antibody During Long-term Treatment of Mice in the Absence of T-cell Anergy and Sustained Cytokine Release". Journal of Immunotherapy 32 (5): 452–464. doi:10.1097/CJI.0b013e3181a1c097. PMID 19609237. edit
- ^ Kischel, R; et al. (2008). "Characterization in primates of MCSP- and CD33-specific human BiTE antibodies for treatment of Melanoma and AML". Proc Am Assoc Cancer Res 99: Abs 2404. http://www.micromet.de/fileadmin/template/main/pdf/download/AACR_2008_MCSP_CD33_BiTE_Poster.pdf.
- ^ Lutterbuese, R; et al. (2008). "Conversion of cetuximab, panitumumab, trastuzumab and omalizumab into T-cell-engaging BiTE antibodies creates novel drug candidates of high potency". Proc Am Assoc Cancer Res 99: Abs 2402. http://www.micromet.de/fileadmin/template/main/pdf/download/AACR_2008_Herceptin_BiTE_Poster.pdf.
- ^ Baeuerle, PA; Reinhardt, C (2009). "Bispecific T-cell engaging antibodies for cancer therapy.". Cancer research 69 (12): 4941–4. doi:10.1158/0008-5472.CAN-09-0547. PMID 19509221.
Further reading