UT-Baptist Research Park

Drugs in Development from RxBio Gaining International Attention as Japan's Radiation Exposure Issues Continue

April 6, 2011

MEMPHIS, Tennessee, April 4, 2011 – As recent events in Japan have caused the world to focus on unintended radiation exposure, attention on a drug from RxBio, one of the incubation companies in the Memphis Bioworks® Foundation’s Incubation Center in Memphis, is gaining considerable national and international attention. Rx100, a radiomitigant that can be administered after exposure to forestall the cascade of events leading to radiation‐induced damage to the body, is currently in the testing and presentation stages within the US government.

There are only a small number of agents presently under development as radiomitigants. Rx100 shows significant promise because of its ability to be administered up to 72 hours after exposure to high levels of radiation – making it arguably the most potent such compound under development. Rx100 protects against damage to both the bone marrow as well as the critical cells of the small intestine.

Testing of Rx100 has demonstrated its unique properties in comparison to other drug candidates in the pipeline. Of significance is the fact that Rx100: a) is a small molecule, b) is essentially nontoxic at therapeutic doses, c) has a long shelf life, d) is nonimmunogenic, e) and provides effective treatment of ARS when administered up to 72 hours after exposure to lethal, whole‐body radiation.

“Rx100 is unique among radioprotectants /radiomitigators in that it boosts natural mechanisms that promote and sustain cell survival in almost every cell type and at the same time inhibits the cascade leading to programmed cell death (apoptosis),” said Dr. W. Shannon McCool, RxBio’s CEO. “Thus, Rx100 augments the good and shuts down the bad. While other products shut down essential cellular signaling mechanisms involved in radiation‐induced cellular injury and tend to lack specificity and/or may be toxic, Rx100 is a specific activator of natural, nontoxic, protective mechanisms of cell survival and antiapoptosis. Among its actions, Rx100 protects critical stem cells. Rx100 can be formulated for a wide range of patient types—from infants to the elderly – and can be administered either orally or subcutaneously.”

In addition, according to RxBio’s CSO Dr. Gabor Tigyi, one of the inventors of the technology and a professor at the University of Tennessee Health Science Center, “Rx100 is a potent protector of the GI tract. This drug provides significant protection to the gut from radiation as well as other toxic substances such as cholera toxin. Among its actions, Rx100 maintains the mucosal barrier of the GI tract. It prevents severe diarrhea and the entry of bacterial toxins into the blood stream – both potentially severe side effects.”

RxBio has recently presented its initial NHP data at the Biomedical Advanced Research and Development Authority (BARDA) meeting that took place in January, 2011, in Washington. BARDA is within the Office of the Assistant Secretary for Preparedness and Response in the U.S. Department of Health and Human Services. The data presented demonstrated significant protection of the all‐important GI tract.

Representatives of both BARDA and the National Institute of Allergy and Infectious Diseases (NIAID) have requested meetings with representatives of RxBio to accelerate development of Rx100. NIAID has additionally expressed interest in follow‐on compounds from RxBio: Rx101 and EDL2000. While Rx101 is related to Rx100, EDL2000 is completely unique, is also a small molecule, is extremely safe, and can be given orally, parenterally, and/or topically.

About Radiation Exposure:
Exposure to radiation can be a cause for concern – especially if radiation levels reach or exceed 1 Gy. Radiation targets rapidly proliferating cells of the body. Cells of the hematopoietic system (bone marrow) and the gastrointestinal (GI) tract are two such cell types. Damage to these cells initiates programmed cell death (apoptosis).

First responders, healthcare professionals, and citizens lack sufficient medications to prevent cellular damage and death due to exposure to significant levels of whole‐body irradiation. Agents that protect from radiation exposure are divided into three categories: 1) Agents that must be administered before cellular exposure to ionizing radiation or “radioprotectants;” 2) Agents that can be administered after exposure and which will forestall the cascade of events leading to radiation‐induced damage or “radiomitigants;” and 3) Agents that can facilitate or promote endogenous recovery from radiation induced damage or “regenerators.”

To date, the FDA has approved a few radioprotectants. These include:
• Prophylactic potassium iodide to protect the thyroid from exposure to excess.
• Laxatives and chelating agents (i.e. diethylene triamine pentaacetic acid (“DTPA”), etc., to decrease exposure by binding and promoting urinary excretion.
• Absorbing agents such as Prussian Blue to limit GI absorption or high oral doses of calcium to compete with intestinal absorption of milk contaminated with strontium.

About RxBio: www.rxbio.com
RxBio is an early stage company formed around novel and proprietary small-molecule technology developed at the University of Tennessee Health Science Center (UTHSC) in Memphis and licensed from the University of Tennessee Research Foundation (UTRF). The company’s near-term focus is the development of novel and proprietary products that protect: a) against lethal whole-body radiation, and b) against damage to the GI tract due to radiation, chemotherapy, and various toxins. Longer term, the company is focused on the development of novel cancer agents as well as agents that block plaque build-up in blood vessels.

About the Memphis Bioworks Foundation: www.memphisbioworks.org
The Memphis Bioworks Foundation, a not-for-profit organization, was formed to lead the collaboration among public, private, academic, and government entities to accelerate the growth of the bioscience industry in the region. Memphis Bioworks strives to leverage and expand the regional strengths in the biosciences through education, research, job training, and commercialization. Memphis Bioworks is leading the development of the UT-Baptist Research Park, which serves as the focal point of the city's biomedical economic development.

For further information on Rx100 or RxBio, contact: W. Shannon McCool, D.Ph., RxBio, Inc., 423-928‐3330; smccool@rxbio.com.

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