Immunomedics, Inc. Reports Humanized Anti-CD20 Antibody Appears Safe And Active In Non-Hodgkin’s Lymphoma

ATLANTA, Dec. 12 /PRNewswire-FirstCall/ -- Immunomedics, Inc. , a leading biopharmaceutical company focused on developing monoclonal antibodies, today reported initial response and safety results with the Company’s humanized anti-CD20 (hA20) monoclonal antibody in patients with non-Hodgkin’s lymphoma (NHL) at the 47th Annual Meeting of ASH. The results were presented by Franck Morschhauser, MD, Centre Hospitalier Regional Universitaire de Lille, Lille, France, lead investigator of the open-label, multi-center, Phase I/II, dose-escalation study.

Thirty-four adult patients with documented CD20-positive B-cell NHL were enrolled and were infused once weekly for four weeks consecutively with 120, 200, 375, or 750 mg/m(2) of hA20. Treatment responses from twenty-three assessable patients with at least one post-treatment evaluation were reported at the meeting. The overall objective response rate was 61% (14/23) with 26% (6/23) of patients having a complete response (CR/CRu). Moreover, complete responses were observed at all dose levels, including 43% (3/7) patients receiving 120 mg/m(2) of hA20, with 28% (2/7) having a partial response. Median infusion times for 375 mg/m(2) of hA20 were 3.3 hours for the first infusion, 2.0 hours for subsequent infusions. At lower initial doses of 120 and 200 mg/m(2) of hA20, infusion times of 2 hours for the first and 1 hour for subsequent infusions were reported.

“We are very encouraged by these preliminary results and are particularly enthused by the high proportion of complete responses in patients who received 120 mg/m2 of hA20, the lowest dose used in the trial. More importantly, a complete response rate of 43% (3/7) was observed in a small group of patients who had 2-4 prior treatments with rituximab,” remarked Cynthia L. Sullivan, President and Chief Executive Officer. “We are in the process of formulating the optimal dose to bring the study to the next phase,” Ms. Sullivan added.

Thirty-three patients received all four infusions with one rituximab- sensitive patient discontinuing treatment after developing allergic reactions at first infusion. Other than mild to moderate transient infusion reactions, predominantly with the first infusion, no significant toxicity was reported. No immunogenicity was seen in twenty-four patients tested at least once. As expected, peripheral blood B-cell depletion occurred after the first infusion and persisted for samples obtained up to 12 weeks following fourth infusion, with analysis ongoing. Pharmacokinetic results after first and fourth infusions demonstrate a mean antibody serum half-life of 5.3 plus or minus 5.3 and 12.0 plus or minus 8.7 days, respectively.

About hA20

hA20 is a humanized monoclonal antibody that binds to the CD20 antigen on B-cells. It contains over 90% of human amino acid sequences and the human framework regions are identical to epratuzumab, the Company’s CD22 humanized antibody that has been studied in over 300 NHL patients. hA20 displays similar binding avidity, specificity, and mechanisms of action, including antibody-dependent cellular cytotoxicity, complement-dependent cytotoxicity, and apoptosis, as rituximab. It has comparable in vitro and in vivo CD20 binding and efficacy against lymphoma as rituximab.

About Immunomedics

Immunomedics is a New Jersey-based biopharmaceutical company 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. Our lead product candidate, epratuzumab, is currently in two pivotal Phase III trials for the treatment of patients with moderate and severe lupus (ALLEVIATE A and B). At present, there is no cure for lupus and no new lupus drug has been approved in the U.S. in the last 40 years. We believe that our portfolio of intellectual property, which includes approximately 90 patents issued in the United States, and more than 250 other issued patents worldwide, protects our product candidates and technologies. Visit our web site at http://www.immunomedics.com.

This release, in addition to historical information, may contain forward- looking statements made pursuant to the Private Securities Litigation Reform Act of 1995. Such statements, including statements regarding clinical trials, out-licensing arrangements, and capital raising activities, involve significant risks and uncertainties and actual results could differ materially from those expressed or implied herein. Factors that could cause such differences include, but are not limited to, risks associated with new product development (including clinical trials outcome and regulatory requirements/actions), competitive risks to marketed products and availability of required financing and other sources of funds on acceptable terms, if at all, as well as the risks discussed in the Company’s filings with the Securities and Exchange Commission. The Company is not under any obligation, and the Company expressly disclaims any obligation, to update or alter any forward-looking statements, whether as a result of new information, future events or otherwise.

For More Information: Dr. Chau Cheng Associate Director, Investor Relations & Business Analysis (973) 605-8200, extension 123 ccheng@immunomedics.com

Immunomedics, Inc.

CONTACT: Dr. Chau Cheng, Associate Director, Investor Relations & BusinessAnalysis of Immunomedics, Inc., +1-973-605-8200, extension 123,ccheng@immunomedics.com

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