SAN DIEGO, April 7, 2014 (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 5 patients reported a partial response as their best response, based on RECIST 1.1 criteria, in the Company's ongoing Phase I/II clinical trial of its investigational antibody-drug conjugate (ADC), IMMU-132, in patients with solid cancers. IMMU-132 is an anti-TROP-2 antibody with SN-38, the active metabolite of irinotecan, linked to the antibody.
Results from this multicenter study, as well as initial data from the expansion phase of the trial, were presented by Dr. Alexander Starodub of Indiana University Health Goshen Center for Cancer Care, Goshen, IN, at the 2014 Annual Meeting of the American Association for Cancer Research (AACR) in San Diego, CA.
Two of the 3 patients with small-cell lung cancer (SCLC), 2 of the seven patients with triple- negative breast cancer, and 1 of the 11 patients with colorectal cancer were partial responders by at least one computer tomography (CT) assessment. In addition to these 5 partial responses, among the 35 patients who had at least one response assessment by CT, 22 patients had stable disease as their best response, giving an overall disease control rate of 77%. Besides colorectal, triple-negative breast, and SCLC, the 35 CT-assessable patients include 14 other types of solid cancer. These patients had failed a median of 4 prior treatments, some including topoisomerase-I and -II inhibiting drugs, and in some cases are showing durable responses up to almost one year.Grade 3 or 4 adverse events (AE) ≥ 8 % were neutropenia (31%), fatigue (10%), and diarrhea (8%), while mild AE ( > 20%) were reported for nausea, fatigue, alopecia, diarrhea and vomiting. IMMU-132 was administered once weekly for two weeks followed by one week of rest in a 3-week cycle. Despite repeated dosing, no antibodies against the ADC, either to the antibody or to the SN-38, have been detected. The conjugate clears completely within 7 days, which is consistent with our preclinical studies showing 50% of the SN-38 is released in the serum every day.