Immunomedics Announces U.S. Patent for Antibody-SN-38 Conjugates

New Patent on F-18 Labeling of Peptides and Proteins Also Issued

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| Source: Immunomedics, Inc.

MORRIS PLAINS, N.J., Dec. 31, 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 announced the issuance of U.S. patent no. 8,617,558 for additional claims under the patent family "Camptothecin-binding moiety conjugates," and U.S. patent no. 8,617,518 with additional claims for the patent family "Methods and compositions for improved F-18 labeling of proteins, peptides and other molecules."

Patent 8,617,558 relates to our proprietary linker technology for conjugating SN-38 to the Company's humanized antibodies for targeted delivery of the potent drug to the tumor. The patent will expire in December 2023. Additional patents covering the Company's antibody-drug conjugates are being prosecuted in major countries worldwide.

"This is a key patent for the protection of our antibody-drug conjugates patent family, of which IMMU-132, an anti-TROP-2-SN-38 conjugate, and IMMU-130, an anti-CEACAM5-SN-38 conjugate, constitute two of our most exciting new agents for solid cancer therapy," commented Cynthia L. Sullivan, President and Chief Executive Officer. "Both IMMU-132 and 130 are in Phase II clinical development and we plan to report results from these studies in the second quarter of 2014 at upcoming scientific and medical conferences."

In early dose-escalation studies, the two antibody-SN-38 conjugates have shown evidence of tumor shrinkage in patients with difficult-to-treat solid tumors who had failed multiple prior therapies, including irinotecan.

SN-38 is the active metabolite of irinotecan, a camptothecin analogue approved for the treatment of metastatic colorectal cancer. While SN-38 is 2 to 3 orders of magnitude more potent than its parent molecule, it does not dissolve in water and cannot be administered directly to patients. Our unique linker allows us to produce antibody-SN-38 conjugates that are soluble in water with excellent yields, as well as preservation of antibody binding and drug activity, even after attaching about 7 drug molecules per antibody.

The second patent, 8,617,518, which will expire in December 2027, concerns the methods and compositions of labeling peptides and other molecules with the diagnostic radioisotope, fluorine-18 (F-18) or the magnetic resonance imaging (MRI) label, fluorine-19 (F-19).

The Company has invented a simple-to-use kit for the rapid labeling of peptides and proteins, including antibodies, to be used as imaging agents for positron-emission tomography (PET) and MRI of diseases. In particular, antibody-based targeting agents, an area of our strength, for immunoPET imaging can become a companion diagnostic to our therapeutic products, including the antibody-drug conjugates currently in clinical trials.

"This is an important technology for us," Ms. Sullivan stated, "and is of interest to major pharmaceutical companies wanting an imaging companion to their therapeutics."

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, clivatuzumab tetraxetan labeled with a radioisotope is in a Phase III pivotal trial in advanced pancreatic cancer patients. Other solid tumor therapeutics in Phase II clinical development include 2 antibody-drug conjugates, IMMU-132 (anti-TROP-2-SN-38) and IMMU-130 (anti-CEACAM5-SN-38). 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 241 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 UCB for the further development of epratuzumab 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.

For More Information:
Dr. Chau Cheng
Senior Director, Investor Relations & Grant Management
(973) 605-8200, extension 123