Company’s First Antibody-Drug Conjugate to Enter Human Testing
Conjugate to be Evaluated in Multiple Myeloma

MORRIS PLAINS, NJ, USA | August 14, 2009| Immunomedics, Inc. (Nasdaq:IMMU – News), a biopharmaceutical company focused on developing monoclonal antibodies to treat cancer and other serious diseases, today announced the allowance of an investigational new drug (IND) application filed with the U.S. Food and Drug Administration (FDA) to initiate a Phase I/II clinical trial of the doxorubicin conjugate of milatuzumab for the treatment of patients with multiple myeloma. This product candidate is the Company’s first antibody-drug conjugate to enter human studies.

The primary objective of the open-label, multi-center study is to evaluate the safety and tolerability of the antibody-drug conjugate in patients with recurrent or refractory multiple myeloma. Preliminary information on efficacy, pharmacokinetics, and immunogenicity will also be obtained.

"Due to its rapidly internalizing nature when bound to the CD74 receptor, milatuzumab is an ideal antibody for the targeted delivery of chemotherapeutic agents, such as doxorubicin, to tumors expressing CD74, as indicated in several articles published by our scientists," commented Cynthia L. Sullivan, President and CEO. "We are pleased with the allowance and are eager to begin the clinical assessment of the antibody-drug conjugate, which has demonstrated very potent anti-tumor activities in preclinical studies," she added. Ms. Sullivan elaborated further: "Our chemists have developed some unique drug conjugation methods that have been applied to doxorubicin, as well as to SN-38, the active principle of irinotecan (CPT-11), a potent drug used in the treatment of metastatic colorectal cancer. Thus, we intend this to be the first in a series of clinical studies to evaluate the therapeutic opportunities for our antibody-drug conjugates."

About Milatuzumab

Milatuzumab is a humanized anti-CD74 antibody constructed using the same constant regions of the heavy and light chains as epratuzumab, whose safety has been demonstrated in clinical trials of patients with B-cell malignancies and autoimmune disorders. Milatuzumab is being studied clinically for the treatment of multiple myeloma, non-Hodgkin’s lymphoma, and chronic lymphocytic leukemia. CD74, also known as invariant chain, has been implicated in antigen processing, particularly by dendritic and other immune cells, but recently has also been disclosed as a survival factor for rapidly proliferating malignant cells. Milatuzumab is the first anti-CD74 antagonistic antibody to enter clinical trials.

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 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 137 patents issued in the United States and more than 300 other patents issued worldwide, protects our product candidates and technologies. 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.

SOURCE: Immunomedics, Inc.