Healthcare Industry News: rituximab
News Release - November 13, 2006
Epratuzumab and Rituximab Have Different Modes of ActionWASHINGTON, Nov. 13 (HSMN NewsFeed) -- Immunomedics, Inc. (Nasdaq: IMMU ), a biopharmaceutical company focused on developing monoclonal antibodies, today reported that studies have shown that epratuzumab and rituximab have distinct mechanisms of action - epratuzumab acts as an immunomodulatory agent while rituximab is an acutely cytotoxic therapeutic antibody with different modes of action. Results from these studies were presented at the 70th annual meeting of the American College of Rheumatology and the 41st annual meeting of the Association of Rheumatology Health Professionals in Washington, DC.
"Epratuzumab's ability to modulate B-cell activities complements rituximab's cell killing property. These two antibodies may be complementary when used in combination for the therapy of non-Hodgkin's lymphoma (NHL) or other B-cell diseases," commented Cynthia L. Sullivan, President and Chief Executive Officer of the Company. "In particular, the immunomodulatory effect of epratuzumab could be important in the treatment of autoimmune diseases. In autoimmune disease, a patient's immune system is already compromised, so physicians have indicated to us that they prefer not to have their patient's peripheral B-cells completely depleted," she further remarked.
Combination therapy of epratuzumab and hA20, an anti-CD20 antibody developed by Immunomedics and in clinical trials in patients with NHL, in mice bearing a transplanted human lymphoma cell line, demonstrated that the addition of epratuzumab to hA20 improved survival over that of hA20 alone. Consistent with this finding was the observation that epratuzumab and rituximab was more effective than rituximab alone in inhibiting the proliferation of B-lymphoma cell lines in vitro. Individually, rituximab, alone or cross-linked with a second antibody, was more effective than epratuzumab in these cell culture systems.
rituximab was also more effective in inducing cell death than epratuzumab, especially in the presence of a cross-linking agent. Combining epratuzumab with cross-linked rituximab did not significantly alter the levels of apoptosis obtained with cross-linked rituximab alone. Likewise, adding epratuzumab to rituximab did not alter rituximab's ability to induce complement-dependent cytotoxicity (CDC), and antibody-dependent cellular cytotoxicity (ADCC). Alone, epratuzumab had a modest but significant effect on ADCC, but did not induce CDC.
In contrast, when the B-cell antigen receptor (BCR) was amplified, immobilized epratuzumab, but not immobilized rituximab, yielded a significant reduction in viable cell count in two NHL cell lines. Independent of BCR activation, immobilized epratuzumab inhibited the growth of lymphoma cells stressed by lack of nutrients, whereas immobilized rituximab had no significant effect.
Results of these studies have previously been published in an on-line article entitled "Epratuzumab, a CD22-targeting recombinant humanized antibody with a different mode of action from rituximab," and authored by J. Carnahan, R. Stein, Z. Qu, K. Hess, A. Cesano, H.J. Hansen and D.M. Goldenberg. The print report will appear in the February 2007 issue of Molecular Immunology.
Immunomedics is a New Jersey-based biopharmaceutical company 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 have recently licensed our lead product candidate, epratuzumab, to UCB, S.A. for the treatment of all autoimmune disease indications worldwide. We have retained the rights for epratuzumab in oncology indications for which UCB has been granted a buy-in option. UCB has development, manufacture and commercialization rights, and is responsible for all clinical trials evaluating epratuzumab for the treatment of patients with moderate and severe lupus. At present, there is no cure for lupus and no new lupus drug has been approved in the U.S. in the last 40 years. We believe that our portfolio of intellectual property, which includes approximately 108 patents issued in the United States, and more than 250 other issued patents worldwide, protects our product candidates and technologies. We also have a majority ownership in IBC Pharmaceuticals, Inc., which is developing a novel dock and lock methodology, 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. Visit our web site at http://www.immunomedics.com.
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), 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), 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.
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