Epratuzumab and Rituximab Produce High Rate and Durable

-- 88.2% Overall Response Rate, Including 42.4% Complete Responses --

-- 60% of Patients Remain in Remission at 3 Years Follow-Up --

MORRIS PLAINS, N.J., Aug. 14, 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 announced that the combination of epratuzumab and rituximab, as a front-line therapy of patients with newly diagnosed follicular lymphoma (FL), produced a high complete response rate and prolonged time to disease progression. Final results from the Phase II CALGB 50701 study sponsored by the National Cancer Institute Study Group, Cancer and Leukemia Group B (CALGB), was published online in the journal Cancer. ¹

The study reported an overall response rate (ORR) of 88.2% in 59 evaluable patients who had completed all courses of treatment. Of these, 25 patients (42.4%) achieved a complete response, 27 patients (45.8%) reported a partial response, and 6 patients (10.2%) had stable disease as their best response. The estimated median progression-free survival is 3.5 years. At 3 years, 60% of patients remain in remission.

Epratuzumab is the Company's proprietary humanized anti-CD22 antibody with strong efficacy as a monotherapy in relapsed FL. ² Although rituximab combined with chemotherapy has improved the survival of previously untreated patients with FL, many patients are unable or unwilling to tolerate chemotherapy. This has led the CALGB to evaluate the combination of epratuzumab and rituximab as initial treatment of patients with FL, with ORR within 12 months of study enrollment as the primary objective of the multi-institution study.

Sixty patients were enrolled by 17 CALGB institutions to receive epratuzumab 360 mg/m ² with rituximab 375 mg/m ² weekly for 4 induction doses. This combination was continued as extended induction in weeks 12, 20, 28, and 36 for a total of 8 doses over 9 months. Therapy was well-tolerated, with toxicities similar to those expected with rituximab alone.

One patient completed all courses of treatment but was not evaluable for response because of death due to bacterial infection before the time of response assessment. Response was assessed by computed tomography imaging.

"We are very encouraged with these high efficacy results of epratuzumab when combined with rituximab in patients with NHL who are naive to therapy," remarked Cynthia L. Sullivan, President and Chief Executive Officer of Immunomedics, Inc. "Further development of this humanized anti-CD22 antibody will be an international Phase III study conducted by the Resistant Disease Committee of the International BFM Study Group to improve the outcome of children and adolescents with acute lymphoblastic leukemia," added Ms. Sullivan.

Reference

1. Grant BW, Jung SH, Johnson JL, Kostakoglu L, Hsi E, Byrd JC, Jones J, Leonard JP, Martin SE, Cheson BD. A phase 2 trial of extended induction epratuzumab and rituximab for previously untreated follicular lymphoma: CALGB 50701. Cancer. 2013 Aug 6. doi: 10.1002/cncr.28299. Epub ahead of print. PMID: 23922187.
2. Leonard JP, Coleman M, Ketas JC, Chadburn A, Ely S, Furman RR, Wegener WA, Hansen HJ, Ziccardi H, Eschenberg M, Gayko U, Cesano A, Goldenberg DM. Phase I/II trial of epratuzumab (humanized anti-CD22 antibody) in indolent non-Hodgkin's lymphoma. J Clin Oncol. 2003 Aug 15;21(16):3051-9. Epub 2003 Jul 1. PMID: 12837807.

About Immunomedics

Immunomedics is a New Jersey-based biopharmaceutical company primarily 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, cytokines 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 2 Phase III clinical trials in lupus. In oncology, we are planning to launch a Phase III pivotal trial for clivatuzumab labeled with a radioisotope in pancreatic cancer. Other solid tumor therapeutics in late-stage clinical development include 2 antibody-drug conjugates, labetuzumab-SN-38 and hRS7-SN-38. We also have a majority ownership in IBC Pharmaceuticals, Inc., which is developing a novel DOCK-AND-LOCK™ (DNL™) method with us for making fusion proteins and multifunctional antibodies. We believe that our portfolio of intellectual property, which includes approximately 227 active patents in the United States and more than 400 foreign patents, protects our product candidates and technologies. Our strength in intellectual property has resulted in the top-10 ranking in the 2012 IEEE Spectrum Patent Power Scorecards in the Biotechnology and Pharmaceuticals category. For additional information on us, please visit our website at www.immunomedics.com . The information on our website does not, however, form a part of this press release.

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 (including the timing and amount of contingent payments), forecasts of future operating results, potential collaborations, 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 any cash payment that the Company might receive in connection with a sublicense involving a third party and UCB, which is not within the Company's control, new product development (including clinical trials outcome and regulatory requirements/actions), our dependence on our licensing partners for the further development of epratuzumab and veltuzumab for non-cancer indications, 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 Senior Director, Investor Relations & Grant Management (973) 605-8200, extension 123