MORRIS PLAINS, N.J., Jan. 29, 2009 (GLOBE NEWSWIRE) -- Immunomedics, Inc. (Nasdaq:IMMU), a biopharmaceutical company focused on developing monoclonal antibodies to treat cancer and other serious diseases, today reported that a single amino acid change in the binding region of veltuzumab improved its potency in preclinical lymphoma models. Results from this study were published by D.M. Goldenberg, E.A. Rossi, R. Stein, T.M. Cardillo, M.S. Czuczman, F.J. Hernandez-Ilizaliturri, H.J. Hansen and C-H. Chang in a paper entitled "Property and structure-function relationships of veltuzumab (hA20), a humanized anti-CD20 monoclonal antibody," in the January 29, 2009, issue of Blood. This study was supported in part by a grant from the National Cancer Institute.
Veltuzumab, a next generation anti-CD20 antibody, was constructed using the same donor frameworks as epratuzumab, the Company's humanized anti-CD22 antibody. Consequently, similar to epratuzumab, veltuzumab can be infused rapidly and has been well tolerated by patients. Veltuzumab's complementarity-determining regions (CDRs) are identical to rituximab, except for one amino acid residue at the 101st position (Kabat numbering) in CDR3 of the variable heavy chain (VH), having aspartic acid (Asp) instead of asparagine (Asn).
When compared to rituximab in 3 human lymphoma cell lines, veltuzumab has significantly reduced off-rates (increased residence time on lymphoma cells) in all cell lines tested, as well as increased complement-dependent cytotoxicity in 1 of 3 cell lines. Mutation studies confirmed that the differentiation of the off-rate between the two anti-CD20 antibodies is related to the single amino acid change in CDR3-VH. Antibody-dependent cell-mediated cytotoxicity, apoptosis and growth inhibition were similar between veltuzumab and rituximab.
Studies in cynomolgus monkeys demonstrated that a single low dose of veltuzumab, given intravenously or subcutaneously, induced peripheral blood and lymphatic organ B-cell depletion. Low doses of veltuzumab, regardless of route of administration, also enhanced survival and even cures in mice bearing human lymphoma. Moreover, in 3 mouse models of human lymphoma, low and high-dose veltuzumab were significantly more effective in vivo than rituximab.
Commenting on these results, Cynthia L. Sullivan, President and CEO, said: "These preclinical findings are consistent with our observations in patients with non-Hodgkin's lymphoma (NHL) or immune thrombocytopenic purpura (ITP) given low doses of veltuzumab, either intravenously or subcutaneously. We expect to conclude the NHL and ITP clinical Phase I/II studies during this current calendar year."
About Immunomedics
Immunomedics is a New Jersey-based biopharmaceutical company primarily focused on the development of monoclonal, antibody-based products for the targeted treatment of cancer, autoimmune and other serious diseases. We have developed a number of advanced proprietary technologies that allow us to create humanized antibodies that can be used either alone in unlabeled or "naked" form, or conjugated with radioactive isotopes, chemotherapeutics or toxins, in each case to create highly targeted agents. Using these technologies, we have built a pipeline of therapeutic product candidates that utilize several different mechanisms of action. We also have a majority ownership in IBC Pharmaceuticals, Inc., which is developing a novel Dock-and-Lock (DNL) methodology for making fusion proteins and multifunctional antibodies, and a new method of delivering imaging and therapeutic agents selectively to disease, especially different solid cancers (colorectal, lung, pancreas, etc.), by proprietary, antibody-based, pretargeting methods. We believe that our portfolio of intellectual property, which includes approximately 134 patents issued in the United States and more than 300 other patents issued worldwide, protects our product candidates and technologies. For additional information on us, please visit our website at www.immunomedics.com. The information on our website does not, however, form a part of this press release.
This release, in addition to historical information, may contain forward-looking statements made pursuant to the Private Securities Litigation Reform Act of 1995. Such statements, including statements regarding clinical trials, out-licensing arrangements (including the timing and amount of contingent payments), forecasts of future operating results, and capital raising activities, involve significant risks and uncertainties and actual results could differ materially from those expressed or implied herein. Factors that could cause such differences include, but are not limited to, risks associated with new product development (including clinical trials outcome and regulatory requirements/actions), our dependence on our licensing partners for the further development of epratuzumab for autoimmune indications and veltuzumab for non-cancer indications, competitive risks to marketed products and availability of required financing and other sources of funds on acceptable terms, if at all, as well as the risks discussed in the Company's filings with the Securities and Exchange Commission. The Company is not under any obligation, and the Company expressly disclaims any obligation, to update or alter any forward-looking statements, whether as a result of new information, future events or otherwise.