Immunomedics Reports Promising Results With Sacituzumab Govitecan in Patients With Metastatic Gastrointestinal Cancers

CHICAGO, June 1, 2015 (GLOBE NEWSWIRE) -- Immunomedics, Inc., (Nasdaq:IMMU) today announced that a majority of patients with heavily-pretreated, metastatic gastrointestinal cancers responded to sacituzumab govitecan, the Company's first-in-class antibody-drug conjugate (ADC), with partial responses and durable stable disease in a mid-stage clinical study.

A total of 65 patients with various types of gastrointestinal cancers had been enrolled into this multicenter study to receive sacituzumab govitecan weekly for the first 2 weeks of a 3-week cycle. At the time of analysis, 60 patients had at least one post-treatment evaluation for response by computed tomography according to rules set by the Response Evaluation Criteria In Solid Tumors (RECIST 1.1).

Best responses, which include partial response and stable disease, from assessable patients who received 8 or 10 mg/kg doses of sacituzumab govitecan are summarized below:

Colorectal Esophageal Gastric Pancreatic*
Number of Patients Enrolled (Assessed) 29 (26) 16 (16) 5 (3) 15 (15)
Partial Response 1 (4%) 2 (13%) 0 0
Stable Disease 14 (54%) 7 (44%) 3 (100%) 7 (47%)

* Included 3 patients who received doses of 12 mg/kg.

Despite the late-stage setting, the overall disease control rate (partial response + stable disease) for all 60 assessable patients was 57%, including 2 esophageal cancer patients and 1 colorectal cancer patient with a partial response.

While patient follow-up is continuing, interim analysis of survival data revealed a favorable outcome in both progression-free survival (PFS) and overall survival (OS).

Colorectal Esophageal* Pancreatic
Number of Patients 29 17 15
Median No. Prior Treatments (Range) 4 (1-8) 3 (1-6) 2 (1-5)
Median PFS in months (Maturity) 3.9 (100%) 4.1 (65%) 1.9 (100%)
Median OS in months (Maturity) 18.0 (38%) 10.8 (29%) 4.2 (87%)

* Included 1 patient who received starting dose of 18 mg/kg and 15 doses at 13.5 mg/kg. This patient had stable disease for 6.9 months.

Sacituzumab govitecan continues to show an acceptable safety profile in these patients with diverse, advanced, heavily-pretreated solid cancers. Grades 3 and 4 adverse events at the doses of 8 and 10 mg/kg include dose-limiting neutropenia (30%), followed by febrile neutropenia (8%), and diarrhea (6%).

"We believe these results with sacituzumab govitecan, as a single agent, in advanced gastrointestinal cancers are promising, especially in patients with metastatic esophageal and colorectal cancers," remarked Cynthia L. Sullivan, President and Chief Executive Officer.

According to the American Cancer Society, the prognosis for patients with metastatic esophageal cancer is poor. With few treatment options, the 5-year relative survival rate for these patients is 4%.

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.

The U.S. Food and Drug Administration has designated sacituzumab govitecan a Fast Track development program for the treatment of patients with metastatic small-cell or non-small cell lung cancers and patients with metastatic triple-negative breast cancer.

Dr. Alexander N. Starodub of Indiana University Health Center for Cancer Care, Goshen, IN, presented the Phase 1/2 study at the 2015 Annual Meeting of the American Society of Clinical Oncology. In addition to Dr. Starodub, the multicenter study also involved Drs. Allyson J. Ocean and Manish A. Shah, Weill Cornell Medical College, New York, NY; Dr. Wells A. Messersmith, University of Colorado Cancer Center, Aurora, CO; Dr. Vincent J. Picozzi, Virginia Mason Cancer Center, Seattle, WA; Dr. Michael J. Guarino, Helen F. Graham Cancer Center & Research Institute, Newark, DE; Dr. Sajeve S. Thomas, UF Health Cancer Center-Orlando Health, Orlando, FL; and Dr. Aditya Bardia, Massachusetts General Hospital Cancer Center, Termeer Center for Targeted Therapies, Boston, MA.

The study in pancreatic cancer patients was supported in part by Award Number R43CA171388 from the National Cancer Institute. The content is solely the responsibility of the Company and does not necessarily represent the official views of the National Cancer Institute or the National Institutes of Health.

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 has an ongoing collaboration with UCB, S.A. (UCB), to whom the Company licensed epratuzumab for the treatment of all non-cancer indications worldwide. UCB expects Phase 3 data in systemic lupus erythematosus in the first half of 2015. Immunomedics is exploring epratuzumab in oncology in collaboration with independent cancer study groups. Immunomedics' most advanced candidate to which it retains worldwide rights for all indications is 90Y-clivatuzumab tetraxetan.

The Company initiated a Phase 3 registration trial in January 2014 in patients with advanced pancreatic cancer and expects patient enrollment to be completed in calendar year 2016. Immunomedics' portfolio of wholly owned product candidates 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 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 267 active patents in the United States and more than 400 foreign patents, protects its product candidates and technologies. Immunomedics' strength in intellectual property has resulted in a top-8 ranking in the Biotechnology industry by the Patent Board for the 2014 fiscal year. For additional information on the Company, please visit its website at 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.comSource:Immunomedics, Inc.