Immunomedics announced the dosing of the first patient in a Phase I/II clinical trial of the doxorubicin conjugate of milatuzumab for the treatment of patients with relapsed multiple myeloma

MORRIS PLAINS, NJ, USA | June 15, 2010 | Immunomedics, Inc. (Nasdaq:IMMU – News), a biopharmaceutical company focused on developing monoclonal antibodies to treat cancer and other serious diseases, today announced the dosing of the first patient in a Phase I/II clinical trial of the doxorubicin conjugate of milatuzumab for the treatment of patients with relapsed multiple myeloma.

Milatuzumab is a new humanized antibody developed by the Company for the treatment of cancer. It is the first antibody to have entered human testing that binds to a marker called CD74. CD74 is an attractive target for antibody therapy because it is present in limited amounts in normal tissues but widely found in leukemias, lymphomas and the vast majority of multiple myeloma cases. It is involved in a cell-to-cell communication pathway that is critical for survival. When CD74 is blocked by milatuzumab, it can lead to cell death. More importantly, CD74 internalizes rapidly once it is bound by milatuzumab, making it an ideal target for the delivery of chemotherapeutic agent against CD74-expressed tumors. Indeed, milatuzumab conjugated with doxorubicin has demonstrated very potent anti-tumor activities in preclinical studies with human lymphomas and myelomas. This product candidate is the Company’s first antibody-drug conjugate (ADC) to be tested clinically.

The open-label, multi-center Phase I/II study aims to evaluate the safety and tolerability of milatuzumab-doxorubicin conjugate in patients with recurrent or refractory multiple myeloma, and to obtain preliminary information on efficacy, pharmacokinetics, and immunogenicity. The ADC will be administered intravenously on days 1, 4, 8, & 11 every 21 days for up to 8 treatment cycles. Four different dose levels of the doxorubicin conjugate of milatuzumab will be studied in groups of 3-6 patients. Once an optimal dose has been found, up to an additional 30 patients will be studied at that dose level.

"We are pleased to have initiated the patient dosing of our first ADC," commented Cynthia L. Sullivan, President and CEO. "Our next ADC candidates will be based on SN-38, the active metabolite of irinotecan (CPT-11) that has been approved for the treatment of metastatic colorectal cancer. We plan to link it with our proprietary humanized antibodies that target solid cancers such as breast, colorectal, lung and ovarian," she added.

About Multiple Myeloma

Multiple myeloma is a plasma cell cancer with occurrence at multiple bone marrow sites. In multiple myeloma, plasma cells constitute 10-80% of the bone marrow cells compared to 1% in normal bone marrow cells. Consequently, abundance of one type of antibody is produced by the B cells, thereby severely limiting the body’s ability to fight infections, leading to localized bone fractures, weakening of muscles, and stress on kidney function. The 5-year survival in newly diagnosed cases of multiple myeloma is ~30%, since resistance to existing therapies develops eventually in almost all patients and 50-75% of patients relapse. In 2009, an estimated 20,580 new cases and 10,580 deaths will be attributable to multiple myeloma in the USA

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 149 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 www.immunomedics.com. The information on our website does not, however, form a part of this press release.

SOURCE: Immunomedics, Inc.