Immunomedics Announces Potent Anti-Tumor Activities with IMMU-114 in Preclinical Study in Acute and Chronic Leukemia

-- Preclinical Study Presented at the 2016 American Association for Cancer Research (AACR) Annual Meeting --
-- Results of Combination Therapies with Sacituzumab Govitecan Also Presented --

NEW ORLEANS, April 18, 2016 (GLOBE NEWSWIRE) -- Immunomedics, Inc. (Nasdaq:IMMU) today reported that, in a preclinical model of human chronic lymphocytic leukemia (CLL), IMMU-114, the Company’s proprietary humanized anti-HLA-DR IgG4 antibody, was superior to anti-CD20 therapy using rituximab, and had an additive effect when combined with kinase inhibitors. Furthermore, IMMU-114 also achieved a significant survival benefit in an animal model of human acute lymphoblastic leukemia (ALL) that is refractory to doxorubicin.

In a Phase 1, first-in-man dose-escalation study, the anti-HLA-DR antibody, as a subcutaneous monotherapy, has produced encouraging clinical responses in patients with relapsed/refractory non-Hodgkin lymphoma (NHL) and CLL, including one NHL patient with a complete response.

The current preclinical study was undertaken to further evaluate the activity of IMMU-114 in CLL and ALL, as compared to anti-CD20 or doxorubicin therapy, respectively, as well as in combination with kinase inhibitors in CLL.

In a mouse model of human CLL that has similar HLA-DR and CD20 expression, IMMU-114 significantly improved median survival time (MST) of 19 days for the rituximab group to more than 42 days, even at doses as low as 50 µg (P<0.0001) (Table 1).

Table 1. Significant survival improvement in mice bearing human CLL tumors treated with IMMU-114 as compared with rituximab.

TreatmentDosageMedian Survival TimeP-Value
IMMU-114200 µg46 days<0.0001
Rituximab18 days
IMMU-114100 µg54 days0.0107
Rituximab18 days
IMMU-11450 µg42 days<0.0001
Rituximab19 days
Saline Control 14 days

In cell culture experiments with a CLL line, IMMU-114 and ibrutinib, the Bruton’s kinase-inhibitor, were found to provide a synergistic growth inhibitory interaction, whereas the combination with idelalisib, a PI3K-inhibitor, produced an additive effect. These results suggest that IMMU-114 could potentially improve the results of other agents used in the therapy of patients with CLL.

For ALL, in a doxorubicin-refractory animal model, IMMU-114 therapy provided a significant survival benefit (MST>39 days) at doses as low as 25 µg, compared to both doxorubicin-treated and saline control animals (MST=23 and 21 days, respectively, P<0.0001) (Table 2).

Table 2. Therapeutic efficacy of IMMU-114 in mice carrying doxorubicin-refractory human ALL tumors

TreatmentMedian Survival TimeP-Value
IMMU-114 (50 µg)42.5 days<0.0001
IMMU-114 (25 µg)39 days<0.0001
Doxorubicin23 days
Saline Control21 days

“These data demonstrate IMMU-114’s overall activity in diverse hematopoietic cancers and provide the rationale for continued clinical and preclinical evaluation alone and combined with current chemotherapeutic agents that are active in their respective indications,” commented Cynthia L. Sullivan, President and Chief Executive Officer.

In a separate poster presentation at this year’s AACR conference, the Company also provided preclinical data for sacituzumab govitecan, the Company’s lead antibody-drug conjugate (ADC) for solid cancer therapy, that demonstrated a synergistic effect when combined with olaparib, a poly (adenosine diphosphoribose) polymerase (PARP) inhibitor, as well as additive therapeutic results with microtubule inhibitors, such as paclitaxel or eribulin mesylate, in various animal models of human triple-negative breast cancer (TNBC).

This ADC has been designated a Breakthrough Therapy by the FDA for the treatment of patients with TNBC who have failed at least 2 prior therapies for metastatic disease. Clinical updates in patients with metastatic urothelial cancer will be presented in an oral session later at the same AACR conference.

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 eight clinical-stage product candidates. Immunomedics’ portfolio of investigational products 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. IMMU-132 has received Breakthrough Therapy Designation from FDA for the treatment of patients with triple-negative breast cancer who have failed at least 2 prior therapies for metastatic disease. 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 combination therapies involving its antibody-drug conjugates, 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 286 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 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.

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