Immunomedics Reports Initial Clinical Results With Hpam4 For Pancreatic Cancer Therapy

Results presented at Society of Nuclear Medicine Annual Meeting

WASHINGTON, DC, USA | June 5, 2007 |
Immunomedics, Inc. (Nasdaq: IMMU), a biopharmaceutical company focused on developing monoclonal antibodies to treat cancer and other serious diseases, today announced that initial results from a Phase I study with the Company's humanized anti-MUC1 monoclonal antibody (hPAM4), labeled with the radioisotope, Yttrium-90 (Y-90), in patients with unresectable and metastatic pancreatic cancer reported at the 54th Annual Meeting of the Society of Nuclear Medicine in Washington, DC, by Seza Gulec, MD, Center for Cancer Care, Goshen, IN, were encouraging.

Stage III pancreatic cancer patients who have failed one line of chemotherapy and Stage IV patients with or without a history of systemic therapy were eligible for the open-label, multicenter dose-escalation study. Prior to therapy, all patients received a diagnostic dose of hPAM4 labeled with the radioisotope, Indium-111, to ensure an acceptable distribution within the body and radiation dose to the pancreas for intended therapy. Patients then received a single infusion of 90Y-hPAM4 with the Y-90 dose escalating in increments of 5mCi/m(2) in groups of 3-6 patients. CT based measurements were used to evaluate tumor response 4, 8, and 12-weeks after therapy.

Results from the Goshen study site were reported at the meeting. Eleven patients, of whom 9 had previously received systemic therapy predominantly with gemcitabine regimens, and 2 patients who were chemotherapy naïve were enrolled at this cancer center. In all patients, pre-therapy imaging with 111In-hPAM4 showed acceptable distribution within the body and radiation dosage to the pancreas. 90Y-hPAM4 was administrated at 15 mCi/m(2), 20 mCi/m(2) or 25 mCi/m(2). One patient, enrolled into the clinical trial at this site, showed shrinkage of a liver lesion.

Two patients, from other study sites, have also had reported tumor shrinkage. All patients, however, showed disease progression at or after week 8. The maximum tolerated dose was 20 mCi/m(2) with bone marrow being the dose-limiting organ.

"Because of the refractory nature of pancreatic cancer, single agent treatment is not expected to offer clinical benefit. Based on this Phase I experience, combined/sequential treatment with chemotherapy and fractionated radioimmunotherapy is being considered for future trials," commented Dr. Gulec.

"We have presented these preliminary results to the FDA and are in discussion with the regulatory authority for a new Phase I dose-escalation study for 90Y-hPAM4 in combination with gemcitabine using smaller Y-90 doses repeatedly," added Cynthia L. Sullivan, President and CEO of Immunomedics.

In addition, the Company presented two posters at today's meeting on the pretargeting of pancreatic cancer and B-cell lymphoma using new bispecific antibodies constructed from the Company's proprietary platform technology for protein engineering termed the dock-and-lock (DNL).

One poster was on TF10, which is a DNL construct with two binding sites for the same MUC1 antigen targeted by PAM4, and a single binding site for the histamine-succinyl-glycine (HSG) peptide. Initial therapy studies showed that pretargeting with TF10 and Y-90 labeled HSG peptide can effectively cause the complete regression of human pancreatic cancer in mice at doses well below the maximum tolerated level.

The other poster was on TF4 for the pretargeting of B-cell lymphoma. Constructed with two sites that target the CD20 antigen and one for the HSG peptide, TF4, when used in combination with radiolabeled HSG-peptide, is highly effective for imaging lymphoma implanted in mouse models either subcutaneously or intravenously. Early results indicate therapy of tumors can be achieved with 500 microCi of Y-90 or less.

About hPAM4
hPAM4 is a humanized monoclonal antibody targeting an epitope in the MUC1 antigen expressed in most pancreatic cancer, but not pancreatitis, normal pancreas or most other normal tissues. Preclinical studies with PAM4 labeled with the radioisotope, Yttrium-90, demonstrated favorable tumor responses, which could be further improved when given in combination with gemcitabine.

About Pancreatic Cancer
According to the National Cancer Institute, pancreatic cancer is the fourth leading cause of cancer death in the United States. In 2007, an estimated 37,000 Americans will be diagnosed with the disease, and about 33,000 patients will die from it. For patients with advanced cancers, the overall 5-year survival rate of all stages is less than 1%. For those patients with small and localized disease that can be completely resected surgically, 5-year survival rates improve to 18% to 24%. Currently, the standard therapy for pancreatic cancer is gemcitabine, alone or in combination with other chemotherapeutics.

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 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. The Company is conducting clinical trials with hA20 in patients with non-Hodgkin's lymphoma, epratuzumab as a potential therapeutic for patients with lymphoma and leukemia, 90Y-epratuzumab for the therapy of patients with lymphoma, 90Y-hPAM4 for pancreas cancer therapy and hCD74 as a therapy for patients with multiple myeloma. 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 (DNL) 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. For additional information on us, please visit our web site 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 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.

SOURCE: Immunomedics, Inc.

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