Biothera Launches Clinical Trial In KRAS-Mutated Colorectal Cancer Patients

Main Category: Colorectal Cancer
Also Included In: Cancer / Oncology;  Respiratory / Asthma
Article Date: 12 Jun 2009 - 3:00 PDT

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Biothera has initiated a Phase II clinical trial in stage IV KRAS-mutated colorectal cancer patients with its investigational drug Imprime PGG® in combination with Erbitux® (cetuximab), the company announced today.

Published research demonstrates that colorectal cancers with mutated KRAS genes do not respond to anti-EGFR monoclonal antibodies such as Erbitux®. However, researchers believe that Imprime PGG® uses the body's own immune system by engaging a type of white blood cell called the neutrophil to fight cancer cells that are coated with antibodies like Erbitux. Such a strategy might be effective against tumors regardless of whether KRAS is mutated or not. Preclinical studies indicate that Imprime PGG® in combination with Erbitux® can reduce tumor growth.

"About 35-40 percent of all colorectal cancers have a mutation in the KRAS gene," said Leonard B. Saltz, M.D., medical oncologist and colorectal cancer expert at Memorial Sloan-Kettering Cancer Center, and principal investigator of the trial. "Erbitux and related antibodies are ineffective against these KRAS-mutated cells."

While Erbitux® doesn't kill cancer cells that have mutated KRAS, it can bind to the tumor cells and activate the binding of another protein in the immune system called complement to the tumor cell. When neutrophils primed with Imprime PGG® bind to the "fixed" complement on the tumor cell, the neutrophils attack the cancer cell. Imprime PGG® is being developed as combination treatment for a wide range of cancers, including colorectal and lung cancer.

"The beauty of this trial design is that since drugs like Erbitux® alone can't work in a KRAS-mutated tumor, if we see patients' tumors shrinking, we'll be pretty confident that it is the presence of the investigational drug that is making that happen," said Saltz.

The open-label, 56-patient KRAS-mutated colorectal cancer study is being conducted at three U.S. locations. Patient enrollment begins this week. All subjects will receive Imprime PGG® at 4 mg/kg weekly plus standard doses of Erbitux®. Tumor measurements and determination of tumor responses for this study will be performed according to Response Evaluation Criteria in Solid Tumors (RECIST).

"Based on the results of our first clinical trial in second- and third-line metastatic colorectal cancer patients, we are excited at the prospect that Imprime PGG® in combination with monoclonal anti-EGFR therapies might provide hope to patients with KRAS-mutated tumors," said Daniel K. Conners, Biothera chairman and Pharmaceutical Group president. "This KRAS-mutated colorectal trial has the potential to become a pivotal trial and may lead to a fast-track application to the FDA."

About Imprime PGG®

Imprime PGG® is a novel immunotherapy that works synergistically with anti-tumor monoclonal antibodies to activate a large population of the body's immune cells (neutrophils) to kill cancer cells. Unlike other drugs that trigger a broad innate immune response, Imprime PGG® selectively activates immune cells without inducing systemic pro-inflammatory cytokines, which reduces potential side effects. As a platform therapeutic in oncology, Imprime PGG® has the potential to improve patient response rates for existing monoclonal antibody therapies in approved indications, create new indications for these drugs and enhance the efficacy of development-stage monoclonal antibody drugs.

Source
Biothera, the Immune Health Company