Immunomedics Reports Updated Results of Labetuzumab-SN-38 in Metastatic Colorectal Cancer

AMSTERDAM, Netherlands, Sept. 30, 2013 (GLOBE NEWSWIRE) -- Immunomedics, Inc. (Nasdaq:IMMU), 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 presented encouraging results from a Phase I dose-escalation trial of its proprietary antibody-drug conjugate (ADC), labetuzumab-SN-38, or IMMU-130, in patients with metastatic colorectal cancer. Dr. Neil H. Segal at the Memorial Sloan-Kettering Cancer Center, New York, NY, reported the updated results at The European Cancer Congress 2013 in Amsterdam, The Netherlands.

Results from 15 very advanced patients who were progressing after prior therapies, including irinotecan, were presented at the Congress. Only 5 patients to-date have been evaluated after completing therapy with 4 or more doses of the ADC, administered once every 2 weeks, with the rest having advancing disease that precluded further therapy. Even at this early stage of clinical development, IMMU-130 has produced a partial response in 1 patient with a duration of response of 4.7 months, or 140 days. This patient had failed multiple prior therapies, including irinotecan.

"We are encouraged by these early results, which appear to show that IMMU-130 is well tolerated within a clinically effective dosage range, and may be active even after its parent molecule, irinotecan, proved to be ineffective," commented Cynthia L. Sullivan, President and Chief Executive Officer of Immunomedics. "A concurrent trial of IMMU-130 with twice-weekly dosing has shown, in the first two patients evaluated by CT, shrinkage of index lesions by 27% and 29%, suggesting that more frequent dosing of IMMU-130 may be more efficacious," Ms. Sullivan added.

The maximum tolerated dose for the once-every-2-weeks dosing schedule has been confirmed to be below 24 mg/kg. This study has moved to a dose expansion stage to evaluate lower doses given once or twice weekly. About 10 clinical sites may participate in this new study. No human anti-humanized antibodies have yet been detected. Serum analysis revealed a quicker removal of the intact conjugate compared with the parent antibody, due in part to the intended release of SN-38 from the ADC.

About Labetuzumab-SN-38 (IMMU-130)

Labetuzumab-SN-38 is one of three agents from the Company's robust ADC program that are in clinical development. Labetuzumab is a slowly-internalizing antibody that recognizes the carcinoembryonic antigen (CEA; CEACAM5 or CD66e), which is expressed in many solid cancers, including more than 80% of colorectal cancer. In prior clinical trials, the antibody was shown to be safe when administered unconjugated or bound to the radioisotope, iodine-131, for radioimmunotherapy.

SN-38 is the active metabolite of irinotecan, which is a standard therapy for patients with metastatic colorectal cancer, but has major gastrointestinal and hematologic toxicity. By targeting SN-38 directly to CEA-expressing tumors, delivery of SN-38 may be increased while mitigating systemic toxicity. Preclinical studies have shown that the antibody-drug linkage was susceptible to cleavage in serum, with 50% of SN-38 released in ~1.0 day, leading to a locally enhanced concentration within the tumor site. In animal models of human colorectal cancer, the ADC exhibited high anti-tumor activity.

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. Our lead product candidate, epratuzumab, is currently in two Phase III clinical trials in lupus. In oncology, we are planning to launch a Phase III pivotal trial for clivatuzumab labeled with a radioisotope in advanced pancreatic cancer patients. Other solid tumor therapeutics in Phase II clinical development include 2 antibody-drug conjugates, labetuzumab-SN-38 (IMMU-130) and hRS7-SN-38 (IMMU-132). We also have a majority ownership in IBC Pharmaceuticals, Inc., which is developing a novel DOCK-AND-LOCK™ (DNL™) method with us for making fusion proteins and multifunctional antibodies. DNL™ is being used particularly to make bispecific antibodies targeting cancers and infectious diseases as a T-cell redirecting immunotherapy, as well as bispecific antibodies for next-generation cancer and autoimmune disease therapies. We believe that our portfolio of intellectual property, which includes approximately 228 active patents in the United States and more than 400 foreign patents, protects our product candidates and technologies. Our strength in intellectual property has resulted in the top-10 ranking in the 2012 IEEE Spectrum Patent Power Scorecards in the Biotechnology and Pharmaceuticals category. 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, potential collaborations, 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 any cash payment that the Company might receive in connection with a sublicense involving a third party and UCB, which is not within the Company's control, new product development (including clinical trials outcome and regulatory requirements/actions), our dependence on our licensing partners for the further development of epratuzumab 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.

CONTACT: For More Information: Dr. Chau Cheng Senior Director, Investor Relations & Grant Management (973) 605-8200, extension 123 ccheng@immunomedics.comSource:Immunomedics, Inc.