AMSTERDAM, Netherlands, Sept. 30, 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 presented encouraging results from a Phase I dose-escalation trial of its proprietary antibody-drug conjugate (ADC), labetuzumab-SN-38, or IMMU-130, in patients with metastatic colorectal cancer. Dr. Neil H. Segal at the Memorial Sloan-Kettering Cancer Center, New York, NY, reported the updated results at The European Cancer Congress 2013 in Amsterdam, The Netherlands. Results from 15 very advanced patients who were progressing after prior therapies, including irinotecan, were presented at the Congress. Only 5 patients to-date have been evaluated after completing therapy with 4 or more doses of the ADC, administered once every 2 weeks, with the rest having advancing disease that precluded further therapy. Even at this early stage of clinical development, IMMU-130 has produced a partial response in 1 patient with a duration of response of 4.7 months, or 140 days. This patient had failed multiple prior therapies, including irinotecan. "We are encouraged by these early results, which appear to show that IMMU-130 is well tolerated within a clinically effective dosage range, and may be active even after its parent molecule, irinotecan, proved to be ineffective," commented Cynthia L. Sullivan, President and Chief Executive Officer of Immunomedics. "A concurrent trial of IMMU-130 with twice-weekly dosing has shown, in the first two patients evaluated by CT, shrinkage of index lesions by 27% and 29%, suggesting that more frequent dosing of IMMU-130 may be more efficacious," Ms. Sullivan added. The maximum tolerated dose for the once-every-2-weeks dosing schedule has been confirmed to be below 24 mg/kg. This study has moved to a dose expansion stage to evaluate lower doses given once or twice weekly. About 10 clinical sites may participate in this new study. No human anti-humanized antibodies have yet been detected. Serum analysis revealed a quicker removal of the intact conjugate compared with the parent antibody, due in part to the intended release of SN-38 from the ADC.