SANTA MONICA, CA, USA I February 19, 2015 I Immunomedics, Inc., (IMMU) today announced that 33% of patients with small cell lung cancer (SCLC) and 31% with non-small cell lung cancer (NSCLC) had their tumor reduced in size by 30% or more, after being treated with sacituzumab govitecan, the Company’s lead investigational antibody-drug conjugate (ADC). Including patients that reported stable disease as their best response, the ADC controls the progression of the cancer in 75% and 56% of NSCLC and SCLC patients, respectively. These patients had either failed to respond to their last lung cancer therapies or their cancer had returned or progressed.

Dr. Francois Wilhelm, Chief Medical Officer, presented the updated results at the 15th Annual Targeted Therapies of Lung Cancer Meeting, an invitation-only meeting sponsored by The International Association for the Study of Lung Cancer (IASLC).

Sacituzumab govitecan is a next generation ADC designed for targeted therapy of solid cancers. The agent was created by site-specifically conjugating a TROP-2-targeting antibody with a high ratio of a moderately toxic drug, SN-38, using a pH sensitive linker. TROP-2 is a receptor found on many human cancer cells, such as cancers of the breast, cervix, colon and rectum, kidney, liver, lung, ovary, pancreas, and prostate, but with only limited expression in normal human tissues. In an animal model of human pancreatic cancer, the ADC delivered up to 135-times the amount of SN-38 to the tumor than when irinotecan, the parent drug of SN-38, was given.

A total of 44 heavily-pretreated patients with relapsed or refractory lung cancer have been enrolled into this multicenter study. At the time of analysis, 16 patients with SCLC and 18 with NSCLC were evaluated by computed tomography for response and time-to-progression (TTP). Despite the late-stage setting, TTP for most patients was longer with sacituzumab govitecan than the duration of their previous lung cancer therapy.

NSCLC is the most common type of lung cancer, accounting for more than 85% of new diagnoses. There are three main subtypes of NSCLC, including adenocarcinoma, squamous cell carcinoma, and large cell carcinoma. Patients with advanced-stage NSCLC are usually treated with chemotherapy, targeted drugs, or some combination of the two. In the current Phase 2 study with sacituzumab govitecan, tumor shrinkage was observed in both adenocarcinoma and squamous cell carcinoma.

SCLC, which accounts for 13% of new cases, is the more aggressive form. Treatment options for SCLC are more limited, usually involve chemotherapy alone or combined with radiation. The 5-year survival rate for patients with SCLC is 6%, which is lower than that for NSCLC patients (21%).

“Advanced lung cancer is difficult to treat. We are, therefore, very encouraged by these early efficacy results,” commented Cynthia L. Sullivan, President and Chief Executive Officer. “We are going to meet with regulatory authorities to formulate a registration pathway for sacituzumab govitecan first in metastatic triple-negative breast cancer, another disease with unmet needs. Meanwhile, discussions with potential partners for the out-licensing of this valuable asset are continuing,” added Ms. Sullivan.

Sacituzumab govitecan continues to produce acceptable safety profile in heavily-pretreated patients, with neutropenia (24% Grades 3 and 4 combined) as the major toxicity. Diarrhea, the typical side effect of irinotecan treatment, was minimal at 3% Grade 3. More importantly, repeated efficacious doses of the ADC can be given to patients over months without evoking any interfering immune response.

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

According to the American Cancer Society, an estimated 221,200 new cases of lung cancer are expected in 2015 in the United States, accounting for about 13% of all cancer diagnoses. The disease 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. Worldwide, the International Agency for Research on Cancer (IARC) estimated a cancer incidence and mortality for lung cancer of 1.825 million new cases and 1.590 million deaths, respectively, in 2012.

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 indicationsis 90Y-clivatuzumab tetraxetan. The Company initiated a Phase 3 registration trial in January 2014 in patients with advanced pancreatic cancer and expects topline data in mid-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(R) protein conjugation technology. The Company believes that its portfolio of intellectual property, which includes approximately 263 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.

SOURCE: Immunomedics