Immunomedics Develops New Antibody-Drug Conjugate for Hematologic Cancer Therapy

Immunomedics Develops New Antibody-Drug Conjugate for Hematologic Cancer Therapy

ORLANDO, Fla., Dec. 7, 2010 (GLOBE NEWSWIRE) -- Immunomedics, Inc. (Nasdaq:IMMU - News), a biopharmaceutical company primarily focused on the development of monoclonal antibody-based products for the targeted treatment of cancer, autoimmune and other serious diseases, today reported that epratuzumab, the Company's humanized anti-CD22 antibody, conjugated with SN-38, the active component of irinotecan, produced significant anti-tumor responses in a mouse model of human lymphoma. Furthermore, combining the antibody-drug conjugate (ADC) with veltuzumab, a second-generation humanized anti-CD20 antibody, enhanced its therapeutic activity without additional toxicity. Results from these preclinical studies were presented at the 52nd annual meeting of the American Society of Hematology.


While monoclonal antibody therapy has had a significant impact on the management of B-cell malignancies, it is most often used in combination with chemotherapy. An improved approach could be to attach the agent directly onto an antibody for targeted delivery of the drug to the tumor. Epratuzumab is an ideal candidate for ADC development because it is an internalizing antibody and clinical studies have shown it to be potentially safe and efficacious as a naked antibody. The potential therapeutic activity of epratuzumab-SN-38 is the combined effect of both the antibody and the drug.


The activity of the ADC was assessed in several hematopoietic tumor cell lines and in mice, inoculated subcutaneously or intravenously with the cell lines. In vivo studies also examined combination therapy using the ADC and veltuzumab.


Studies in 4 B-cell lymphoma cell lines and 4 acute lymphoblastic leukemia cell lines confirmed the potent in vitro activity of epratuzumab-SN-38 in the nanomolar range. Significant anti-tumor activity was also observed in mice bearing human lymphoma cells. Treatments of animals 5 days after tumor cell implantation with 300 micrograms of the conjugate given twice-weekly for 4 weeks increased median survival from 42 days in untreated animals to 63 days.


Substantial improvement in therapeutic activity was observed when veltuzumab was included. The addition of 35 micrograms of veltuzumab prolonged median survival to more than 160 days with 6 of 10 animals surviving. These results indicate that the epratuzumab-SN-38 conjugate is a potentially potent therapeutic, which can be significantly enhanced when combined with anti-CD20 immunotherapy, representing a new ADC treatment regimen.


"Targeted delivery of drug by an antibody is an exciting approach in cancer treatment. We plan to continue to develop ADCs looking specifically for agents that have a wide therapeutic window with minimal side effects," remarked Cynthia L. Sullivan, President and Chief Executive Officer. "The SN-38 conjugate of epratuzumab is one of several agents created by our ADC program. We are pleased to report these encouraging results and look forward to bringing it into the clinic in the future," Ms. Sullivan added.


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, cytokines 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 with us 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 154 patents issued in the United States and more than 375 other patents issued worldwide, protects our product candidates and technologies. For additional information on us, please visit our website at 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.



Immunomedics, Inc.Dr. Chau Cheng, Director, Investor Relations & Grant Management(973) 605-8200, extension [email protected]