Press Release Source: Immunomedics, Inc. On Friday January 21, 2011, 10:00 am EST

SAN FRANCISCO, Jan. 21, 2011 (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 announced that repeated therapy cycles of its proprietary antibody, clivatuzumab tetraxetan, labeled with yttrium-90 (Y-90) plus low-dose gemcitabine at 200 mg/m2, extended median overall survival (OS) to 11.8 months, more than double the 5.4 months OS in patients treated with a single cycle. Increased Y-90 doses also improved responses; patients receiving a dose of 12 mCi/m2 or higher once a week for 3 weeks reporting a median OS of 8.0 months versus 6.0 months at doses of 9 mCi/m2 or less, once a week for 3 weeks.

These encouraging results were updated at the 2011 Gastrointestinal Cancers Symposium, which is co-sponsored by the American Gastroenterological Association Institute, the American Society of Clinical Oncology, the American Society for Radiation Oncology, and the Society of Surgical Oncology.

At the Symposium, results from 50 evaluable patients were reported. The overall disease control rate for all dose groups, including those that received gemcitabine at greater than 200 mg/m2, was 60%, with 7 patients (14%) reporting a partial response by RECIST criteria (i.e., responses showing decreases in tumor size of more than 30% by CT and the absence of new lesions) and 23 patients (46%) with disease stabilization. Metabolic imaging with PET and the biomarker, CA19-9, both provided supportive evidence of anti-tumor activity.

Commenting on these encouraging results, Dr. Allyson Ocean of the new York Presbyterian Hospital, Weill Medical College of Cornell University, new York, NY, stated, “This is the first time we are reporting survival benefits with this antibody, which are significant in pancreatic cancer. Shrinkage of primary tumors in patients with advanced, inoperable pancreatic cancer is extremely rare. Equally important are improvements in quality-of-life, particularly in the reduction of pain, we have witnessed in our patients.”

to date, more than 70 patients with locally advanced or metastatic pancreatic cancer have been treated with the regimen involving Y-90-labeled clivatuzumab tetraxetan administered once a week for 3 weeks, in combination with gemcitabine. Treatments were well tolerated, including 16 patients retreated with 1-3 additional cycles, with few non-hematologic side effects. In spite of higher cumulative Y-90 doses, hematologic suppression was transient and occurred without major infections or bleeding events.

The open-label study is continuing with new patients enrolled to receive Y-90-labeled clivatuzumab tetraxetan at 12 mCi/m2 once a week for 3 weeks, and gemcitabine at higher doses, including the standard-of-care dose of 1000 mg/m2.

“We are pleased that clivatuzumab tetraxetan continues to produce encouraging results in this difficult-to-treat disease, and we look forward to evaluating this compound in randomized clinical trials,” remarked Cynthia L. Sullivan, President and CEO of Immunomedics. “We plan to complete this dose-escalation study shortly and to seek regulatory advice on protocols designed to determine response rates and overall survival for the future development of this agent,” added Ms. Sullivan.

The multicenter study includes physicians and staff from new York (New York Presbyterian Hospital, Weill Medical College of Cornell University), Delaware (Helen F. Graham Cancer Center at Christiana Care, Newark), Indiana (Goshen Center for Cancer Care), Florida (University of Miami Sylvester Comprehensive Cancer Center; Florida International University Herbert Wertheim College of Medicine, Miami), Ohio (Ohio State University College of Medicine, Columbus) and new Jersey (Garden State Cancer Center, Belleville; Immunomedics, Inc., Morris Plains).

About Clivatuzumab

Clivatuzumab or hPAM4 is a humanized monoclonal antibody targeting a mucin antigen expressed in most pancreatic cancers, but not pancreatitis, normal pancreas or most other normal tissues. Preclinical studies in mice with human pancreatic cancer xenografts given the murine version of Y-90 PAM4 demonstrated favorable tumor responses, which could be further improved when given in combination with gemcitabine. a prior Phase I single dose-escalation study of Y-90 clivatuzumab tetraxetan in treatment-relapsed pancreatic cancer patients has also produced encouraging results, with evidence of objective responses. The radiolabeled humanized antibody is currently in a Phase I/II fractionated dose-escalation study in combination with gemcitabine for the treatment of patients with newly diagnosed, untreated, stage III or stage IV cancer of the pancreas.

About Pancreatic Cancer

According to the American Cancer Society, pancreatic cancer is the fourth leading cause of cancer death in the United States. In 2010, an estimated 43,140 Americans were diagnosed with the disease, and about 36,800 patients died from it. it is often called a silent disease because it is difficult to detect and symptoms do not usually appear until the cancer has grown and often spread beyond the pancreas for quite some time. Pancreatic cancer is difficult to diagnose because there are no symptoms in the early stages and because, when symptoms appear, they can be confused with other diseases.

The treatment options depend on stage and location of the cancer, age, and general health of the patient. Potentially curative surgeries are performed when the cancer has started in the head of the pancreas (near the bile duct), which can allow earlier detection when bile duct blockage produces jaundice. Palliative surgery is a type of surgery chosen when the tumor is too widespread and is done to relieve the symptoms or complications caused by the cancer. if the cancer has not spread beyond the pancreas, therapy can be successful, but it is rare to find pancreatic cancer in the early stages. In later stages, various forms of chemotherapy or combinations of radiation and chemotherapy are given to try to control the disease, and ultimately therapy strives to comfort the patient and reduce pain.

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 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.