— Repeated Cycles of 90Y-Clivatuzumab Treatments Extended Survival When Compared to Single Cycle —
— Low-Dose Gemcitabine in Combination with 90Y-Clivatuzumab Significantly Improved Efficacy of Treatment Regimen —
Company Planning Phase III Registration Trial —

BARCELONA, Spain I July 3, 2013Immunomedics, Inc. (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 encouraging results from the Phase Ib study with clivatuzumab labeled with the radioisotope, yttrium-90 (90Y), in patients with metastatic pancreatic cancer who had received at least 2 prior treatments. Results from this trial were reported by Edith Mitchell, MD, from the Kimmel Cancer Center of Thomas Jefferson University in Philadelphia, PA, in an oral presentation at the European Society for Medical Oncology (ESMO) 15th World Congress on Gastrointestinal Cancer.

 Clivatuzumab is a humanized antibody developed by the Company for the treatment of pancreatic cancer. It targets a specific tumor marker produced by almost all pancreatic cancers that is not usually present in pancreatitis, normal pancreas or most other normal tissues. The Company has previously reported a median overall survival (OS) of 11.8 months in patients with newly diagnosed, untreated, advanced pancreatic cancer after receiving repeated cycles of the 90Y-labeled antibody in combination with low-dose gemcitabine.1

The current Phase Ib study of clivatuzumab was undertaken in pancreatic cancer patients with two or more prior therapies. For these relapsed patients, there is no agreed standard-of-care, and options for further therapy are limited. Clivatuzumab may offer an attractive alternative, especially for those patients with adequate performance status who are unable or unwilling to accept the side effects of additional chemotherapy. The objective of this multicenter trial was to evaluate the safety, tolerability, and evidence of efficacy of the 90Y-labeled-clivatuzumab treatment regimen in previously-treated patients with metastatic pancreatic cancer, and to determine the contribution of low-dose gemcitabine to the treatment regimen.

A total of 58 patients were randomized to receive either 90Y-labeled-clivatuzumab once-a-week for 3 weeks at 6.5 mCi/m2 with gemcitabine 200 mg/m2 given weekly x 4 weeks (Arm A) or 90Y-labeled-clivatuzumab alone (Arm B). This treatment cycle was repeated every 4 weeks until unacceptable toxicity, patient deterioration or patient withdrawal. Patients were followed for one year or until death. The median age of these patients was 65, with a median of 1.6 years from initial diagnosis, and a median of 3 (2-6) prior treatments.

Results from 53 patients who completed at least one treatment cycle were presented. The median overall survival (OS) for Arm A (90Y-labeled-clivatuzumab with low-dose gemcitabine, N=27) was 119 days, a significant improvement over Arm B (90Y-labeled-clivatuzumab alone, N=26), with a median OS of 80 days (P=0.04). Furthermore, for the 23 patients who received multiple cycles of therapy, the median OS increased to 157 days in Arm A compared with 103 days in Arm B.

Survival was also related to patients’ Karnofsky Performance Status (KPS) scores at study entry, increasing from a median of 79 days for patients with 80% KPS to 119 days for patients with 90-100% KPS. In contrast, increased number of prior treatments is a negative prognostic indicator for survival. The median OS decreased from 90 to 82 to 73 days for patients who received 2, 3, or 4-5 prior treatments, respectively.

 “We are very encouraged with these results, and we believe this study demonstrated the feasibility of conducting clinical trials in pancreatic cancer patients relapsed to 2 or more prior treatments. We have made the strategic decision to move forward with a Phase III clinical trial, positioning clivatuzumab in this setting as a therapy for patients with advanced pancreatic cancer who have few to no treatment options,” remarked Cynthia L. Sullivan, President and Chief Executive Officer. “We have designed and vetted our protocol with key opinion leaders and FDA, selected our clinical research organization, and plan to enroll the first patient into the Phase III clinical trial by the end of this calendar year, or the beginning of 2014. Most of our clinical trial sites will be in the US, with some additional sites in the EU,” Ms. Sullivan added. “For future clinical trials, KPS and number of prior treatments will be considered as important survival prognosticators,” concluded Ms. Sullivan.

 Based on the 2013 Cancer Facts and Figures report by the American Cancer Society, an estimated 45,220 Americans will be diagnosed with pancreatic cancer in 2013, making it the 10th most common cancer diagnosis among men and the 9th most common among women in the U.S. It is, however, the fourth leading cause of cancer death among both men and women nationwide, with approximately 38,460 deaths expected, or about 7% of all cancer deaths.

 The outlook for pancreatic cancer patients is bleak, with median survival ranges from 4.5 months for the most advanced stage to 24.1 months for the earliest stage. For patients with the advanced disease, treatment options are limited to gemcitabine alone or in combination with other agents. Although FOLFIRINOX, the drug combination of leucovorin, fluorouracil, irinotecan, and oxaliplatin, has recently been shown to prolong survival in patients with newly-diagnosed advanced disease, many patients could not tolerate this treatment regimen.

Reference

1. Ocean A.J., Pennington K.L., Guarino M.J., Sheikh A., Bekaii-Saab T., Serafini A.N., Lee D., Sung M.W., Gulec S.A., Goldsmith S.J., Manzone T., Holt M., O’Neil B.H., Hall N., Montero A.J., Kauh J., Gold D.V., Horne H., Wegener W.A., Goldenberg D.M. Fractionated radioimmunotherapy with (90) Y-clivatuzumab tetraxetan and low-dose gemcitabine is active in advanced pancreatic cancer: A phase 1 trial. Cancer. 2012 Nov 15;118(22):5497-506. doi: 10.1002/cncr.27592. Epub 2012 May 8.

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. We also have a majority ownership in IBC Pharmaceuticals, Inc., which is developing a novel DOCK-AND-LOCK(TM) (DNL(TM)) method with us for making fusion proteins and multifunctional antibodies, and a new method of delivering imaging and therapeutic agents selectively to disease, especially different solid cancers (colorectal, lung, pancreas, etc.), by proprietary, antibody-based, pretargeting methods. We believe that our portfolio of intellectual property, which includes approximately 223 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.

SOURCE: Immunomedics