ATLANTA, Dec. 11, 2012 (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 that subcutaneous administration of veltuzumab, as a single agent, demonstrated promising activity in patients with relapsed immune thrombocytopenia (ITP), even in more heavily treated patients with the chronic disease, and in patients with chronic lymphocytic leukemia (CLL). Veltuzumab is a second generation humanized anti-CD20 antibody constructed using the same human donor frameworks as epratuzumab, the Company's humanized anti-CD22 antibody. The complementarity-determining regions (CDRs) of veltuzumab are identical to rituximab, except for one amino acid residue, which appears to give veltuzumab some unique properties. In an animal model of human lymphoma, veltuzumab demonstrated higher efficacy than rituximab, and in cell culture experiments, this humanized antibody showed slower off-rates and increased complement-dependent cytotoxicity compared to rituximab. In a published study, veltuzumab reversed life threatening anemia and thrombocytopenia in a patient with systemic lupus erythematosus who was unresponsive to rituximab. In non-Hodgkin lymphoma (NHL) patients who had received prior therapies, 4 once-weekly infusions of veltuzumab produced a complete response rate of 25% in a study of 84 patients, even at the low dose of 80 mg/m 2 given intravenously. A subcutaneous formulation with a high concentration of veltuzumab was developed to avoid the need for lengthy intravenous administration and dedicated infusion suites. Published results show this formulation, which can be administered within a few seconds due to the low injection volume, to be active in patients with NHL. (For more information, please refer to the Company's 2011 publication by Negrea et al. in Haematologica, volume 96, pages 567-73). In the presentation given at this ASH meeting, two subcutaneous dosing cohorts were evaluated in a Phase I/II study in relapsed ITP. The first cohort of 34 patients received 2 veltuzumab doses at 80, 160 or 320 mg administered 2 weeks apart for a total dose of 160, 320 or 640 mg, respectively. The second cohort is enrolling patients to receive veltuzumab at 320 mg per dose given once-weekly for 4 weeks for a total dose of 1280 mg. Thus, four different doses are being evaluated.