BOSTON, Nov. 9, 2015 (GLOBE NEWSWIRE) -- Immunomedics, Inc. (Nasdaq:IMMU) today announced that patients with metastatic triple-negative breast cancer (TNBC) lived for a median of seven months without tumor progression, after receiving at least 3 doses of sacituzumab govitecan, the Company's lead investigational antibody-drug conjugate (ADC) for solid cancer therapy, in a Phase 2 clinical study. The study also indicated that the responses were very durable, showing a median time-to-progression, based on computed tomography, of 9.4 months (range of 1.8+ to 13.2+ months), which included patients with stable disease, and partial and complete responses.
"Patients in this late-stage setting usually have a median PFS of three to four months when treated with other agents," stated Aditya Bardia, MD, MPH, Assistant Professor of Medicine at Harvard Medical School, Attending Physician at the Massachusetts General Hospital Cancer Center in Boston, and an investigator in this trial. "Sacituzumab govitecan is a promising agent that offers hope for these patients with poor prognosis," Dr. Bardia added.
Interim results from 54 assessable patients were presented by Steven Jay Isakoff, MD, PhD, Instructor of Medicine at Harvard Medical School, Attending Physician at the Massachusetts General Hospital Cancer Center. These patients had received a median of 5 (range, 2 – 12) prior lines of therapy, which must have included a taxane, a class of chemotherapy agents used to treat solid cancers, such as breast, gastric, head and neck, lung, ovarian, pancreatic, and prostate. All patients had received sacituzumab govitecan at the optimal dose of 10 mg/kg given on days 1 and 8 of a 3-week cycle, and in some patients the therapy continued for many months.
At the time of this analysis, the interim median PFS for the 54 TNBC patients was 7.0 months, with 55% of these patients having experienced a PFS event. Median overall survival data were too early to report, with 87% of patients still alive. The overall objective response rate was 31.5% (17 of 54 patients), including 2 patients with a confirmed complete response. An additional 24 patients had stable disease, resulting in a disease control rate of 76%. Treatment response was assessed by computed tomography based on the rules set by the Response Evaluation Criteria In Solid Tumors (RECIST 1.1).
"We are very encouraged by these efficacy results, particularly the PFS data," remarked Cynthia L. Sullivan, President and Chief Executive Officer of Immunomedics. "The FDA has agreed with us to use PFS as the primary endpoint for the Phase 3 trial in the same patient population," she added.
Sacituzumab govitecan, or IMMU-132, is a first-in-class 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. The ADC has received Fast Track designation from the FDA for the treatment of patients with TNBC, small-cell and non-small-cell lung cancers, and has also been designated an orphan drug for the treatment of patients with small-cell lung or pancreatic cancer in the U.S., and for the treatment of patients with pancreatic cancer in the European Union.
Sacituzumab govitecan has a highly tolerable safety profile. In the 119 patients receiving the ADC at the dose of 10 mg/kg, the major toxicity reported was Grades 3 or 4 neutropenia in 15% of patients, followed by anemia (6%), diarrhea (6%), and febrile neutropenia (4%), and no immune responses against the ADC or its components from patients' own immune system, despite repeated cycle of therapy.
Besides Drs. Bardia and Isakoff, other Principal Investigators who participated in this multicenter study include Dr. Ingrid A. Mayer, Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, TN; Dr. Jennifer R. Diamond, University of Colorado Cancer Center, Aurora, CO; Dr. Alexander N. Starodub, Indiana University Health Center for Cancer Care, Goshen, IN; Dr. Rebecca L. Moroose, UF Health Cancer Center, Orlando, FL; Drs. Allyson J. Ocean and Linda T. Vahdat, Weill Cornell Medical College, New York, NY; Dr. Michael J. Guarino, Helen F. Graham Cancer Center & Research Institute, Newark, DE; Dr. Kevin Kalinsky, Columbia University Medical Center, New York, NY; and Dr. Joyce A. O'Shaughnessy, Baylor Sammons Cancer Center, Texas Oncology, Dallas, TX.
About Triple-Negative Breast Cancer (TNBC)
TNBC is a serious disease, with an annual incidence estimated to be about 40,000 people, 20,000 for metastatic TNBC (mTNBC), in the United States. mTNBC is insensitive to most of the available targeted therapies for breast cancer treatment, including HER2-directed therapy (such as trastuzumab), and endocrine therapies (such as tamoxifen or the aromatase inhibitors). The median overall survival is 10-13 months and the median PFS is usually 3-4 months. There is currently no single standard chemotherapy to treat patients with relapsed/refractory mTNBC. Rapid relapse, with visceral and brain metastases are very common.
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 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 preclinical 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 273 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), the Company's dependence on business collaborations in order to further develop our products and finance our operations, the risk that we or any of our collaborators may be unable to secure regulatory approval of and market our drug candidates, 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.