MORRIS PLAINS, N.J., May 13, 2014 (GLOBE NEWSWIRE) -- Immunomedics, Inc., (Nasdaq:IMMU) today announced the issuance of U.S. patent no. 8,722,047 for the Company's patent application "Humanized anti-HLA-DR antibodies," with an expiration date of May 26, 2026. The new patent concerns compositions of humanized anti-HLA-DR antibodies of use for disease therapy. The allowed claims protect IMMU-114, which is being investigated as a monotherapy in a newly-opened Phase I dose-escalation trial in patients with relapsed or refractory non-Hodgkin lymphoma or chronic lymphocytic leukemia. HLA-DR is a receptor located on the cell surface whose role is to present foreign objects to the immune system for the purpose of eliciting an immune response. Increased presence of HLA-DR in hematologic cancers has made it a prime target for antibody therapy. Although other anti-HLA-DR antibodies have been developed, IMMU-114 is distinguished by having a different immunoglobulin class, IgG4, which does not function by the usual effector-cell activities of antibodies, such as complement-dependent cytotoxicity (CDC) and antibody-dependent cellular cytotoxicity (ADCC). As a result, IMMU-114 does not rely on an intact immune system in the patient to kill tumor cells. Furthermore, because ADCC and CDC are believed to play a major role in causing the side effects of antibody therapy, IMMU-114 is expected to be less toxic to patients. IMMU-114 has exhibited in vitro and in vivo cytotoxicity on a number of human lymphoma cell lines, as well as a panel of leukemia cell lines. Moreover, in one animal model of human NHL, treatment with the anti-HLA-DR antibody was more effective than rituximab in yielding 100% long-term survival. "IMMU-114 is another innovative product candidate our research scientists have developed," remarked Cynthia L. Sullivan, President and Chief Executive Officer. "Our recent work on its mechanism of action demonstrated that the anti-HLA-DR antibody exerts its exceptional anti-tumor activity through disruption of 2 cellular signaling pathways, ERK and JNK, that are critical for cell growth. This mechanism of action clearly differentiates IMMU-114 from other antibody-based therapies of B-cell cancers, which may allow for combination therapies with other antibodies to be developed. We are pleased to receive this patent protection," Ms. Sullivan concluded.