The Experts below are selected from a list of 12426 Experts worldwide ranked by ideXlab platform
David M. Goldenberg - One of the best experts on this subject based on the ideXlab platform.
-
improving the therapeutic index in cancer therapy by using Antibody drug conjugates designed with a moderately cytotoxic drug
Molecular Pharmaceutics, 2015Co-Authors: Serengulam V Govindan, Thomas M Cardillo, Edmund A Rossi, Preeti Trisal, William J Mcbride, Robert M Sharkey, David M. GoldenbergAbstract:The Antibody–drug conjugate (ADC), IMMU-130, of the moderately cytotoxic topoisomerase I inhibitor, SN-38, and the CEACAM5-targeted Humanized Antibody (mAb), labetuzumab, was evaluated in model systems of human colon carcinoma and in phase I clinical trials of heavily pretreated patients with metastatic colorectal cancer. The conjugate, designed with a near-homogeneous drug substitution of 7–8 SN-38/mAb and with a linker that released 50% of the drug in ∼20 h, showed significant antitumor effects compared to a nontargeted ADC in human tumor xenografts, which could be augmented in combination with bevacizumab. The advantage of fractionated dosing was demonstrated, with potential implications for the clinical dosing schedule. Biodistribution comparing IMMU-130 with labetuzumab showed that the conjugate cleared somewhat faster from the blood, but this did not affect tumor uptake and retention. The use of an ultrastable linker in the conjugate design abrogated antitumor effects. A tolerability study in rabbit...
-
abstract lb 34 targeted delivery of sirnas to diverse solid cancers by a novel immunoconjugate comprising tetrameric human protamine linked to an internalizing anti trop 2 Humanized Antibody
Cancer Research, 2010Co-Authors: Pankaj Gupta, David M. Goldenberg, Chienhsing ChangAbstract:Despite the potential of RNA interference (RNAi) to silence specific genes, the full therapeutic potential of RNAi remains to be realized due to the lack of an effective delivery system to target cells in vivo. To address this critical need and prompted by the promising results obtained with fusion proteins comprising the nucleic-acid-binding human protamine and a cell-targeting Fab or scFv, we have developed novel immunoconjugates having multiple copies of human protamine tethered to a tumor-targeting, internalizing Antibody for targeted delivery of siRNAs in vivo. The Dock-and-Lock (DNL) method developed by us provides the design and strategy for building such multifunctional agents. DNL enables site-specific, self-assembly of two modular components with each other, resulting in a stable covalent structure of defined composition with retained bioactivity. The basic strategy of DNL involves the generation of two types of modules, one containing the dimerization and docking domain (DDD) of cAMP-dependent protein kinase (PKA) and the other containing the anchoring domain (AD) of a related A-kinase anchoring protein (AKAP). Docking a DDD-containing module with an AD-containing module occurs spontaneously, and the resulting complex is locked with disulfide bonds to enhance in vivo stability. We generated DDD2-L-thP1, a DDD-module of truncated human protamine (thP1, residues 8 to 29 of full human protamine 1), in which the sequences of DDD2 and thP1 are fused to the light chain of a Humanized Antibody at the N- and C-termini, respectively. The reaction of DDD2-L-thP1 under mild redox conditions with hRS7-IgG-AD2, an AD-module derived from an anti-TROP-2, internalizing, Humanized Antibody, resulted in the facile formation of the desirable DNL complex, designated E1-L-thP1, which contains four copies of thP1 appended to the carboxyl termini of the heavy chains. The purity and molecular integrity of E1-L-thP1 following Protein A purification was shown by size-exclusion HPLC and SDS-PAGE. In addition, the ability of E1-L-thP1 to bind plasmid DNA or siRNAs was demonstrated by the gel shift assay. E1-L-thP1 was effective in protecting the bound DNA from digestion by nucleases added to the sample or present in serum, and its function to carry siRNAs into TROP-2 expressing cancer cells was confirmed by fluorescence microscopy using FITC-conjugated siRNAs and the human lung cancer cell line, Calu-3. Further evaluation of the in vitro and in vivo efficacy of E1-L-thP1 for delivery of CD74-specific siRNAs to treat TROP-2 expressing pancreatic cancer is ongoing. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-34.
-
epratuzumab a cd22 targeting recombinant Humanized Antibody with a different mode of action from rituximab
Molecular Immunology, 2007Co-Authors: Josette Carnahan, Kristen Hess, Zhengxing Qu, Hans J. Hansen, Rhona Stein, Alessandra Cesano, David M. GoldenbergAbstract:Abstract Epratuzumab is a Humanized anti-CD22 monoclonal Antibody currently in clinical trials for treatment of non-Hodgkin lymphoma (NHL) and certain autoimmune diseases. Here we report the results of investigations of epratuzumab's mode of action in comparison to and in combination with the anti-CD20 mAb, rituximab. In vitro cell growth inhibition, induction of apoptosis, and the ability of the mAbs to mediate complement-dependent cytotoxicity (CDC) and Antibody-dependent cellular cytotoxicity (ADCC) were evaluated. We also investigated the potential activity of epratuzumab in the regulation of B-cell antigen receptor (BCR) activation. Epratuzumab and rituximab displayed very distinct modes of action; epratuzumab acts as an immunomodulatory agent, while rituximab is an acutely cytotoxic therapeutic Antibody. Epratuzumab has distinct effects on cell growth from rituximab. For example, rituximab + anti-human IgG Fcγ yielded marked inhibition of proliferation in human NHL cell lines, while epratuzumab had little or no effect in this assay. However, when cells were immobilized and stimulated with anti-IgM, epratuzumab, but not rituximab, caused a significant antiproliferative effect. Unlike rituximab, no CDC could be detected, and ADCC was modest but significant with epratuzumab. Importantly, combining rituximab and epratuzumab did not decrease rituximab's ability to induce apoptosis, CDC, and ADCC. In fact, the combination is more effective than rituximab alone in inhibiting proliferation of Daudi Burkitt lymphoma cells in the presence of second Antibody, and at least equally effective to rituximab in the absence of crosslinking. These observations suggest that it may be possible to enhance clinical efficacy by combination therapy comprised of anti-CD20 and anti-CD22 mAbs.
Hyo Jeong Hong - One of the best experts on this subject based on the ideXlab platform.
-
enhanced humanization and affinity maturation of neutralizing anti hepatitis b virus pres1 Antibody based on antigen Antibody complex structure
FEBS Letters, 2015Co-Authors: Jin Hong Kim, Philippe Gripon, Fidaa Bouezzedine, Mun Sik Jeong, Seung-wook Chi, Seong-eon Ryu, Hyo Jeong HongAbstract:To improve a previously constructed broadly neutralizing hepatitis B virus (HBV)-specific preS1 Humanized Antibody (HzKR127), we further Humanized it through specificitydetermining residue (SDR) grafting. Moreover, we improved affinity by mutating two residues in heavy-chain complementarity-determining regions (CDR), on the basis of the crystal structure of the antigen–Antibody complex. HzKR127-3.2 exhibited 2.5-fold higher affinity and enhanced virus-neutralizing activity compared to the original KR127 Antibody and showed less immunogenic potential than HzKR127. Enhanced virus-neutralizing activity was achieved by the increased association rate, providing insights into engineering potent Antibody therapeutics for HBV immunoprophylaxis. HzKR127-3.2 may be a good candidate for HBV immunoprophylaxis.
-
affinity maturation of an anti hepatitis b virus pres1 Humanized Antibody by phage display
Journal of Microbiology, 2007Co-Authors: Gihyeok Yang, Sun Ok Yoon, Myung Hee Jang, Hyo Jeong HongAbstract:: In a previous study we generated an anti-Hepatitis B Virus (HBV) preS1 Humanized Antibody (HzKR127) that showed in vivo HBV-neutralizing activity in chimpanzees. However, the antigen-binding affinity of the Humanized Antibody may not be sufficient for clinical use and thus affinity maturation is required for better therapeutic efficacy. In this study, phage display technique was employed to increase the affinity of HzKR127. All six amino acid residues (Glu95-Tyr96-Asp97-Glu98-Ala99-Tyr100) in the heavy (H) chain complementarydetermining region 3 (HCDR3) of HzKR127 were randomized and phage-displayed single chain Fv (scFv) library was constructed. After three rounds of panning, 12 different clones exhibiting higher antigen-binding activity than the wild type ScFv were selected and their antigen-binding specificity for the preS1 confirmed. Subsequently, five ScFv clones were converted to whole IgG and subjected to affinity determination. The results showed that two clones (B3 and A19) exhibited an approximately 6 fold higher affinities than that of HzKR127. The affinity-matured Humanized antibodies may be useful in anti-HBV immunotherapy.
-
stability of murine chimeric and Humanized antibodies against pre s2 surface antigen of hepatitis b virus
Biologicals, 2003Co-Authors: Sung Sup Park, Jeongho Kim, John F Brandts, Hyo Jeong HongAbstract:We have constructed a Humanized Antibody with specificity for the pre-S2 surface antigen of hepatitis B virus (HBV) by grafting the complementarity determining regions (CDRs) of parental murine monoclonal Antibody (mAb) into human anti-Sm Antibody framework regions. The Humanized Antibody has a substitution at position 94 in a framework region of the heavy chain variable region, and exhibits the same antigen binding affinity as the parental murine monoclonal and chimeric antibodies. In order to assess the stability of these antibodies, thermal inactivation of the parental, chimeric and Humanized antibodies was analyzed. Fifty percent inactivation of the chimeric and Humanized antibodies was observed at 63.7 degrees C and 68.7 degrees C, respectively, compared to 55.0 degrees C for murine Antibody. The Humanized Antibody also exhibited increased stability against denaturant. Guanidine-induced unfolding monitored by the changes in fluorescence intensity at 360 nm showed that midpoints of the transition of the chimeric and Humanized antibodies were 2.47 M and 2.56 M, respectively, whereas that of the murine Antibody was 1.36 M.
Leonard G. Presta - One of the best experts on this subject based on the ideXlab platform.
-
simple quantitative live cell and anti idiotypic Antibody based elisa for Humanized Antibody directed to cell surface protein cd20
Journal of Immunological Methods, 2004Co-Authors: Kyu Hong, Leonard G. Presta, Wai Lee Wong, Ashley Penn, Camellia W Adams, Anan Chuntharapai, Jihong Yang, Gloria Y MengAbstract:Rituxan, a chimeric anti-CD20 Antibody, has been used for treating non-Hodgkin's lymphoma and some autoimmune diseases. However, a Humanized anti-CD20 Antibody is desirable for long-term treatment of autoimmune diseases. CD20 is an integral membrane protein with a small intervening extracellular loop. Lacking a native soluble CD20 protein, we developed a simple cell-based enzyme-linked immunosorbent assay (ELISA) using live WIL2 cells in a 96-well format to measure relative binding affinity to support the humanization process. Although WIL2 cells grow in suspension and require centrifugation during the wash steps, the assay was quantitative and reproducible. We also demonstrated that cloned adherent transfected Chinese hamster ovary (CHO) cells could be used to improve assay throughput. For clinical studies requiring quantification of the Humanized Antibody in serum, we used an alternate approach and developed a high throughput ELISA using an anti-idiotypic Antibody as a surrogate antigen for capture and an anti-idiotypic Antibody for detection to overcome serum effects. These assay strategies may be applied for characterization of other antibodies directed to multitransmembrane proteins.
-
generation of a Humanized high affinity anti tissue factor Antibody for use as a novel antithrombotic therapeutic
Thrombosis and Haemostasis, 2001Co-Authors: Leonard G. Presta, Gloria Y Meng, Paul Sims, Paul Moran, Sherron Bullens, Stuart Bunting, Jill Schoenfeld, David G Lowe, Patricia Rancatore, Mark IversonAbstract:Blocking the cofactor function of human tissue factor may be beneficial in various coagulation-mediated diseases. The murine Antibody D3 binds to the membrane proximal substrate interaction region of human tissue factor and blocks tissue factor function even in the presence of bound factor VIIa. The cloned murine D3 Antibody was Humanized and affinity matured by exchanging amino acids in the complementarity determining regions as well as in the Antibody framework. The Humanized Antibody, D3H44, bound to tissue factor with a 100-fold increased affinity (KD 0.1 nM) as compared to the original murine and chimeric versions. Depending on the particular disease, different pharmacokinetic properties of the Antibody may be required and, therefore, several Antibody variants – F(ab), F(ab’)2, IgG2, IgG4 and IgG4b – were generated. In vitro, the Humanized D3 antibodies displayed potent inhibition of plasma clotting and tissue factor: factor VIIa-mediated activation of factors IX and X (e. g. D3H44-F(ab’)2, IC50 (F.X) 47 pM). In addition, D3H44-F(ab’)2 completely prevented fibrin deposition in a human ex vivo thrombosis model under venous blood flow conditions (IC50 37 nM). The Humanized D3 antibodies may be utilized for treatment of cardiovascular diseases which involve tissue factor activity, e. g. acute coronary syndrome and venous thrombosis.
-
Antibody humanization using monovalent phage display
Journal of Biological Chemistry, 1997Co-Authors: Manuel Baca, Shane J. O'connor, Leonard G. Presta, James A WellsAbstract:Antibody humanization often requires the replacement of key residues in the framework regions with corresponding residues from the parent non-human Antibody. These changes are in addition to grafting of the antigen-binding loops. Although guided by molecular modeling, assessment of which framework changes are beneficial to antigen binding usually requires the analysis of many different Antibody mutants. Here we describe a phage display method for optimizing the framework of Humanized antibodies by random mutagenesis of important framework residues. We have applied this method to humanization of the anti-vascular endothelial growth factor murine monoclonal Antibody A4.6.1. Affinity panning of a library of Humanized A4.6.1 Antibody mutants led to the selection of one variant with greater than 125-fold enhanced affinity for antigen relative to the initial Humanized Antibody with no framework changes. A single additional mutation gave a further 6-fold improvement in binding. The affinity of this variant, 9.3 nM, was only 6-fold weaker than that of a murine/human chimera of A4.6.1. This method provides a general means of rapidly selecting framework mutations that improve the binding of Humanized antibodies to their cognate antigens and may prove an attractive alternative to current methods of framework optimization based on cycles of site-directed mutagenesis.
Vanessa Izquierdosanchez - One of the best experts on this subject based on the ideXlab platform.
-
biodistribution and tumor uptake of 67 ga nimotuzumab in a malignant pleural mesothelioma xenograft
Molecules, 2018Co-Authors: Oscar Arrieta, Vanessa Izquierdosanchez, Sae Munizhernandez, Hector Vazquezbecerra, Judith Pachecoyepez, Mario Romeropina, Luis Alberto MedinaAbstract:Malignant pleural mesothelioma (MPM) is the most common tumor of the pulmonary pleura. It is a rare and aggressive malignancy, generally associated with continuous occupational exposure to asbestos. Only a multimodal-approach to treatment, based on surgical resection, chemotherapy and/or radiation, has shown some benefits. However, the survival rate remains low. Nimotuzumab (h-R3), an anti-EGFR (epidermal growth factor receptor) Humanized Antibody, is proposed as a promising agent for the treatment of MPM. The aim of this research was to implement a procedure for nimotuzumab radiolabeling to evaluate its biodistribution and affinity for EGF (epidermal growth factor) receptors present in a mesothelioma xenograft. Nimotuzumab was radiolabeled with 67Ga; radiolabel efficiency, radiochemical purity, serum stability, and biodistribution were evaluated. Biodistribution and tumor uptake imaging studies by microSPECT/CT in mesothelioma xenografts revealed constant nimotuzumab uptake at the tumor site during the first 48 h after drug administration. In vivo studies using MPM xenografts showed a significant uptake of this radioimmunoconjugate, which illustrates its potential as a biomarker that could promote its theranostic use in patients with MPM.
Junji Furuse - One of the best experts on this subject based on the ideXlab platform.
-
japanese phase i study of gc33 a Humanized Antibody against glypican 3 for advanced hepatocellular carcinoma
Cancer Science, 2014Co-Authors: Masafumi Ikeda, Shinichi Ohkawa, Takuji Okusaka, Shuichi Mitsunaga, Satoshi Kobayashi, Chigusa Morizane, Ikue Suzuki, Shunsuke Yamamoto, Junji FuruseAbstract:GC33 is a Humanized mAb against human glypican-3 (GPC3). In the first-in-human study carried out in the USA, GC33 was well tolerated and showed preliminary antitumor activity in patients with advanced hepatocellular carcinoma. This study aimed to assess the safety, tolerability, and pharmacokinetic characteristics of GC33 in Japanese patients with advanced hepatocellular carcinoma. The study design was a conventional 3 + 3 dose-escalation design to determine the maximum tolerated dose of GC33 given i.v. at 5, 10, or 20 mg/kg weekly. Immunohistochemistry was carried out on tumor biopsies to evaluate GPC3 expression. Thirteen patients were enrolled across the three dose levels, and no patients observed any dose-limiting toxicity up to the highest planned dose of 20 mg/kg. The most common adverse events were decreased lymphocyte count, decreased natural killer cell count, increased C-reactive protein, and pyrexia. Grade 3 adverse events (increased blood pressure, decreased lymphocyte count, and decreased platelet count) were observed in two or more patients. The AUCinf showed a dose-proportional increase from the 5 mg/kg dose group to the 20 mg/kg dose group. The trough concentrations of GC33 appeared to reach a steady state after the fourth to the sixth dose. Seven of the 13 patients showed stable disease, the other six showed progressive disease. Furthermore, three patients showed long-term stable disease of more than 5 months. In conclusion, GC33 given at up to 20 mg/kg weekly was well tolerated in Japanese patients with advanced hepatocellular carcinoma.