Daily News: Disease

Study Finds Imprime PGG-bound Immune Cells Penetrate Tumor Microenvironment and Enhance Cancer Killing

Business Wire

10-03-13

EAGAN, Minn.--(BUSINESS WIRE)-- Imprime PGG(R), an immunomodulator, is able to enhance antitumor function of immune cells and direct a high percentage of these cells to the tumor microenvironment, according to in vivo data presented recently at the American Association for Cancer Research's (AACR) Third International Conference on Frontiers in Basic Cancer Research in National Harbor, MD. The data was presented by researchers at Biothera, in collaboration with the University of Minnesota.

Biothera recently completed a Phase 2b clinical study in non-small cell lung cancer (NSCLC) with Imprime PGG, cetuximab (Erbitux(R)) and two chemotherapeutic drugs. Additionally, Imprime PGG is in a metastatic colorectal cancer Phase 3 clinical study with cetuximab and a second NSCLC Phase 2b clinical study with bevacizumab (Avastin(R)) and two chemotherapeutic drugs. Imprime PGG is also being studied as a possible treatment in chronic lymphocytic leukemia and non-Hodgkins lymphoma.

Previous in vivo tumor model research has demonstrated the synergistic effect of Imprime PGG in combination with antitumor monoclonal antibodies against a wide range of cancers. The new research broadens the understanding of Imprime PGG's mechanism of action and its potential as an immunomodulator.

Immunotherapeutic-based approaches for the management of many cancer types is an area of increasing study worldwide, according to Myra Patchen, Ph.D., chief scientific officer at Biothera. "These observations further validate the potential benefit of combining Imprime PGG with antitumor monoclonal antibodies as a treatment strategy in cancer."

Imprime PGG targets different effector cell populations (neutrophils and macrophages) than most other immunotherapies: these "innate" immune cell populations represent approximately 60 percent of the immune cells in the body and are normally not involved in anti-tumor activity.

"Engaging the largest population of immune cells in the fight against cancer makes Imprime PGG an immunotherapeutic drug candidate with tremendous potential against multiple cancer types," said Dan Conners, president, Biothera Pharmaceutical Group. "This study enhances our understanding of the significant benefits we are seeing in clinical trials to date."

In the study, immunodeficient mice, with or without tumors, were administered a single dose of Imprime PGG. Three days later, immune cells in peripheral blood, spleen, and/or tumor were isolated and evaluated for Imprime PGG binding and function.

In tumor-bearing mice there was a significantly higher number of neutrophils and macrophages in the tumor microenvironment and tumor tissue of Imprime-treated mice vs the control group and the majority of those tumor-infiltrating leukocytes were shown to be binding Imprime PGG. Furthermore, Imprime PGG also enhanced the antitumor function of these cells, as measured by secretion of antitumor cytokines (TNFa, MIP- , IP-10) and cytotoxicity.

The presentation, "Immune cell priming and potentiation of anti-tumor effects by Imprime PGG(R)," was authored by Yumi Yokoyama, Mariana. I. Nelson, Nadine C. Ottoson, Richard Walsh, Kyle S. Michel, Michael E. Danielson and Mary A. Antonysamy of Biothera; and Mark N. Kirstein of the University of Minnesota.

About Imprime PGG(R) Imprime PGG is a novel immunomodulatory drug in development as a cancer therapy. Innate immune cells are the most abundant immune cells in the body and normally responsible for pathogen killing, but not anti-tumor activity. In preclinical cancer models, however, Imprime PGG has been shown to bind to neutrophils and monocytes and redirect their killing ability to reduce tumor growth and enhance long-term survival. This targeted mechanism is synergistic with multiple anti-tumor monoclonal antibodies, demonstrating the potential to improve patient outcomes in a wide range of cancer indications. Imprime PGG is currently being evaluated in a multiple clinical trials for colorectal cancer, non-small cell lung cancer and chronic lymphocytic leukemia. For more information, view the Biothera drug pipeline.

About Biothera, the Immune Health Company Biothera is a U.S. biotechnology company dedicated to improving immune health. The company is developing pharmaceuticals that engage the innate immune system to fight cancer.

Biothera, the Immune Health Company David Walsh, 651-256-4606 (direct) VP Communications dwalsh@biothera.com

Source: Biothera

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