Immunomedics Reports Interim Phase 2 Results With Sacituzumab Govitecan in Lung Cancers

DENVER, Sept. 8, 2015 (GLOBE NEWSWIRE) — Immunomedics, Inc., (Nasdaq: IMMU) today announced that sacituzumab govitecan, the Company’s lead investigational antibody-drug conjugate (ADC), continues to produce durable responses in patients with metastatic lung cancer who had relapsed or were refractory to their last cancer therapy. At the time of this analysis, a total of 57 patients with metastatic lung cancer (28 non-small-cell lung cancer (NSCLC) and 29 small-cell lung cancer (SCLC)) had been enrolled into this multicenter study at doses ranging from 8-18 mg/kg given on days 1 and 8 every 21 days. The median number of prior lines of therapy in the NSCLC and SCLC patients was 3 and 2.5, respectively. Across all tumor types, 12 mg/kg was declared the maximal tolerated dose and 10 mg/kg declared the recommended Phase 2 dose. Accrual at 10 mg/kg continues.

Treatment response in lung cancer patients administered doses of ≤12 mg/kg was assessed by computed tomography using the rules set by the Response Evaluation Criteria In Solid Tumors (RECIST 1.1). In NSCLC, the most common type of lung cancer, 6 of 19 patients achieved an objective response (objective response rate = 32%). In SCLC, 6 of 20 patients achieved an objective response (objective response rate = 30%). In the 10 mg/kg cohorts, the objective response (partial response) rates in NSCLC and SCLC were 3/10 (30%) and 3/5 (60%), respectively.

In NSCLC, the interim median progression-free survival (PFS), which is the length of time patients are living without their cancer progressing, was 5.4 months for those patients receiving sacituzumab govitecan at the dose level of 10 mg/kg. At the time of analysis, fifty-six percent of NSCLC patients in this dose group had experienced a PFS event. For patients with SCLC, interim median PFS was 4.6 months at the 10 mg/kg dose level. At the time of analysis, eighty-three percent of SCLC patients in this dose group had experienced a PFS event. Overall survival (OS) data were too early to report.

“These results, while still early, seem to show noticeable activity of this drug in a heavily pretreated lung cancer population,” commented Dr. D. Ross Camidge, Joyce Zeff Chair in Lung Cancer Research at the University of Colorado Cancer Center, who presented these data in an Oral Session at the 16th World Conference on Lung Cancer.

“Based on these compelling results, we consider both NSCLC and SCLC to be of primary interest, along with triple-negative breast, esophageal, urothelial, and colorectal cancers, for further study with sacituzumab govitecan,” remarked Cynthia L. Sullivan, President and Chief Executive Officer of Immunomedics. “Updated results in these other solid cancers are expected at future national and international cancer conferences,” Ms. Sullivan added.

According to the American Cancer Society, lung cancer accounts for more deaths than any other cancer in both men and women. An estimated 158,040 deaths are expected to occur in 2015, accounting for about 27% of all cancer deaths.

Sacituzumab govitecan is a first-in-class antibody-drug conjugate (ADC) developed by the Company by conjugating the moderately-toxic drug, SN-38, site-specifically and at a high ratio of drug to antibody, to a humanized antibody that targets the TROP-2 receptor expressed by many solid cancers. SN-38 is the active metabolite of irinotecan (Camptosar), which is used to treat certain solid cancers, particularly metastatic colorectal cancers, as a part of combination therapies, so its pharmacology and properties are well-known.

In addition, the ADC also continues to demonstrate a highly tolerable and easily managed toxicity profile, despite repeated dosing. In the 31 lung cancer patients receiving sacituzumab govitecan at the dose of 10 mg/kg, the major toxicity reported was 10% Grades 3 and 4 neutropenia. Remarkably, there was no reported incidence of Grade 3 or 4 diarrhea, which is a major side effect with irinotecan. At 10 mg/kg 13% of lung cancer patients required a dose reduction in sacituzumab govitecan.

Dr. Wells A. Messersmith, a colleague of Dr. Camidge at the University of Colorado Cancer Center, also participated in this multicenter study. Other Principal Investigators include Dr. Alexander N. Starodub, Indiana University Health Center for Cancer Care, Goshen, IN; Dr. Allyson J. Ocean, Weill Cornell Medical College, New York, NY; Drs. Aditya Bardia and Rebecca Heist, Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, MA; Dr. Sajeve S. Thomas, UF Health Cancer Center, Orlando, FL; and Drs. Gregory A. Masters and Michael J. Guarino, Helen F. Graham Cancer Center & Research Institute, Newark, DE.

About Immunomedics

Immunomedics is a clinical-stage biopharmaceutical company developing monoclonal antibody-based products for the targeted treatment of cancer, autoimmune disorders and other serious diseases. Immunomedics’ advanced proprietary technologies allow the Company to create humanized antibodies that can be used either alone in unlabeled or “naked” form, or conjugated with radioactive isotopes, chemotherapeutics, cytokines or toxins. Using these technologies, Immunomedics has built a pipeline of nine clinical-stage product candidates. Immunomedics’ most advanced candidate is 90Y-clivatuzumab tetraxetan. The radiolabeled antibody is in a Phase 3 registration trial in patients with advanced pancreatic cancer. Immunomedics expects patient enrollment to be completed in calendar year 2016. Immunomedics’ portfolio of investigational products also includes antibody-drug conjugates (ADCs) that are designed to deliver a specific payload of a chemotherapeutic directly to the tumor while reducing overall toxic effects that are usually found with conventional administration of these chemotherapeutic agents. Immunomedics’ most advanced ADCs are sacituzumab govitecan (IMMU-132) and labetuzumab govitecan (IMMU-130), which are in Phase 2 trials for a number of solid tumors and metastatic colorectal cancer, respectively. Immunomedics has licensed epratuzumab to UCB, S.A., (UCB) for the treatment of all autoimmune disease indications worldwide. In oncology, Immunomedics has a research collaboration with Bayer to study epratuzumab as a thorium-227-labeled antibody. Immunomedics has other ongoing collaborations in oncology with independent cancer study groups. The IntreALL Inter-European study group is conducting a large, randomized Phase 3 trial combining epratuzumab with chemotherapy in children with relapsed acute lymphoblastic leukemia at clinical sites in Australia, Europe, and Israel. Immunomedics also has a number of other product candidates that target solid tumors and hematologic malignancies, as well as other diseases, in various stages of clinical and pre-clinical development. These include bispecific antibodies targeting cancers and infectious diseases as T-cell redirecting immunotherapies, as well as bispecific antibodies for next-generation cancer and autoimmune disease therapies, created using its patented DOCK-AND-LOCK® protein conjugation technology. The Company believes that its portfolio of intellectual property, which includes approximately 268 active patents in the United States and more than 400 foreign patents, protects its product candidates and technologies. For additional information on the Company, please visit its website at www.immunomedics.com. The information on its 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 (including the funding therefor, outcomes, timing or associated costs), 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, new product development (including clinical trials outcome and regulatory requirements/actions), our dependence on UCB for the further development of epratuzumab for non-cancer indications, risks associated with the outcome of pending litigation and 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.

CONTACT: For More Information:
         Dr. Chau Cheng
         Senior Director, Investor Relations & Corporate Secretary
         (973) 605-8200, extension 123
         ccheng@immunomedics.com

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