NEW ORLEANS, June 18, 2008 (PRIME NEWSWIRE) -- Immunomedics, Inc. (Nasdaq:IMMU), a biopharmaceutical company focused on developing monoclonal antibodies to treat cancer and other serious diseases, today presented promising preclinical results on pretargeted therapy of pancreatic cancer that can be further improved when given in small fractions repeatedly, and in combination with gemcitabine.
The pretargeted therapy involved TF10, a humanized bispecific antibody that binds to the same pancreatic cancer mucin as the antibody PAM4. TF10 was created by the Company's protein engineering platform technology known as Dock-and-Lock (DNL), developed with scientists of IBC Pharmaceuticals, Inc., a majority-owned subsidiary of Immunomedics. Mice bearing human pancreatic cancer cells were first given the DNL-derived antibody. Sixteen hours later, yttrium-90 (Y-90) labeled histamine-succinyl-glycine (HSG) peptide was injected, and then became bound by the bispecific antibody on the tumor, thus achieving selective targeting of the therapeutic.
This pretargeted system arrested the growth of established tumors without appreciable hematologic toxicity, and extended median survival time (MST) to 4.9 weeks compared to 3.7 weeks from the untreated group. MST improved to 18.9 weeks when the pretargeted therapy was administered in 3 fractions, 1 fraction every 4 weeks in combination with gemcitabine. Gemcitabine alone had no significant effect on inhibiting tumor growth, extending MST to only 4.4 weeks.
"These results suggested that fractionated radioimmunotherapy potentially can be applied to pretargeting," said Cynthia L. Sullivan, President and CEO. "We have previously reported that adding a small amount of Y-90-labeled PAM4 to a full dose regimen of gemcitabine in a fractionated manner greatly enhanced anti-tumor activity in animal studies, and we are pleased to report that patient dosing has begun in our Phase Ib dose escalation study of fractionated Y-90-labeled hPAM4 plus gemcitabine in patients with pancreatic cancer," Ms. Sullivan added.
Results from a biodistribution and nuclear imaging study of TF10 in pancreatic cancer xenografts were recently published in the June 15, 2008, issue of Cancer Research. Preclinical results on fractionated radioimmunotherapy with Y-90 labeled PAM4 and gemcitabine for pancreatic cancer were published in the September, 2003, issue of Clinical Cancer Research.
This study was supported in part by a grant from the National Cancer Institute.
In a separate poster presentation, results from a pretargeted tumor imaging study in colorectal cancer patients were reported.
Twelve patients with primary colorectal cancer were enrolled in this open-label, single-arm, trial to optimize a pretargeting system that utilizes an indium-111-(In-111)-labeled peptide in combination with a bispecific antibody (bsMAb) that binds to the carcinoembryonic antigen expressed in excess by colorectal cancers. In pretargeting, a bsMAb is given as the first injection. When non-tumor-bound bsMAb has substantially cleared non-target tissues and bsMAb has reached a maximum level in the tumor, the bsMAb-recognizable peptide is administered. The latter agent either targets the bsMAb localized at the tumor, or it is rapidly removed in the urine. In this study, best imaging results were obtained 24 hours after peptide administration, with a three- or four-day interval between bsMAb and peptide injection.
Immunomedics' president and CEO, Cynthia Sullivan, again remarked: "We are encouraged that our pretargeting method is showing the anticipated improved targeting and imaging in cancer patients, giving us confidence that eventual therapy studies in patients are worthy of pursuit as a potential advance over prior methods of radioimmunotherapy."
About Immunomedics
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 exclusively licensed our lead product candidate, epratuzumab, to UCB for the treatment of all autoimmune disease indications worldwide. Epratuzumab's most advanced clinical testing is for the treatment of systemic lupus erythematosus (SLE) and in non-Hodgkin's lymphoma (NHL). 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 have retained the rights for epratuzumab in oncology indications, and are advancing trials in lymphoma and in childhood acute lymphoblastic leukemia in cooperation with National Cancer Institute Study Groups. In addition, the Company is conducting clinical trials with intravenous veltuzumab in patients with NHL and immune thrombocytopenic purpura, subcutaneous veltuzumab in NHL and chronic lymphocytic leukemia (CLL), (90)Y-epratuzumab for the therapy of patients with lymphoma, (90)Y-hPAM4 combined with gemcitabine for pancreatic cancer therapy, and milatuzumab (anti-CD74 humanized antibody) as a therapy for patients with multiple myeloma, NHL, and CLL. 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. The Company is working to advance this new technology into clinical testing, advancing the prospects of a personalized cancer therapy strategy. We believe that our portfolio of intellectual property, which includes approximately 116 patents issued in the United States and more than 295 other patents issued worldwide, protects our product candidates and technologies. For additional information on us, please visit our website at http://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, patent protection, 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 partner for the further development of epratuzumab for autoimmune 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.