Researchers Gain New Insights into Cancer-Killing Mechanism of Biothera Compound

EAGAN, MN – June 13, 2005 – Researchers have expanded their understanding of how Biothera’s beta glucans enhance the effectiveness of monoclonal antibody therapy to kill cancer. In the June 2005 Journal of Immunology, they report on the key role of complement blood protein C5a in directing beta glucan-primed immune cells to the site of a tumor.

The researchers demonstrate complement protein C5a directs neutrophils primed with Biothera’s beta glucans (Imprime PGG or Imprime WGP) to the site of a tumor.

In the preclinical study, tumor regression did not occur when C5a was blocked, reflecting its role in neutrophil movement. When C5a was present, neutrophils primed with Biothera’s Imprime PGG or Imprime WGP significantly reduced the size of the tumors in the lymphoma model.

“C5a works like a traffic cop directing the primed neutrophils to the site of a tumor,” said Jun Yan, MD, PhD, corresponding author on this paper and a researcher in the Tumor Immunobiology program at the James Graham Brown Cancer Center, University of Louisville. “Determining the role of C5a further increases our understanding of how we can use this technology to develop more effective cancer therapies.”

New Finding Advances Previous Research
The new research results extend the findings of a series of previous papers by the authors.

Previous research demonstrated how Biothera’s beta glucans engage neutrophils, the most abundant immune cell in the body, to fight cancer. These cells normally do not recognize cancer as “non-self” and therefore do not attack it. To initiate killing, researchers discovered that neutrophils have receptors with two binding sites that must be occupied.

One of the binding sites is often occupied with a blood protein called complement (iC3b) that coats the tumor once it is targeted with antibodies, either the patient’s natural antibodies or monoclonal antibody therapy. The other site usually remains vacant. It is designed for beta glucan, which is found on yeast or fungal cell walls but not present on cancer cells.

Researchers determined that administration of Biothera’s beta glucan compounds bind to the second neutrophil receptor and trigger killing. In essence, the neutrophils now “see” the cancer as foreign and attack.

Researchers believe that Biothera’s compounds may greatly increase the effectiveness of monoclonal antibody therapies for cancer, including Herceptin and Rituxan (Genentech) and Erbitux (ImClone Systems).

Biothera is scheduled to begin a Phase I clinical trial later this year with its lead compound, Imprime PGG. A Phase II clinical trial in breast cancer patients using combination therapy of Imprime PGG and Herceptin is being planned for 2006.

About Biothera, the Immune Health Company
Biothera is a biotechnology company dedicated to improving immune health. The company's primary focus is developing pharmaceuticals whose unique mechanism of action engages immune cells not normally involved in the fight against cancer. In addition, Biothera’s healthcare group manufactures and markets food-grade immune-enhancing ingredients for the nutritional supplement, functional food, cosmetic and the animal feed and nutrition markets.

David Walsh
VP, Communications
Biothera, the Immune Health Company
[email protected]

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