Chiron and Gen-Probe Announce Agreement With America's Blood Centers; Agreement Expands Efforts to Protect U.S. Blood Supply.

EMERYVILLE, Calif.--(BW HealthWire)--March 22, 1999--Chiron Corporation (Nasdaq:CHIR) and Gen-Probe Incorporated announced today that the two companies have entered into an agreement with America's Blood Centers (ABC) to evaluate a new blood screening system that may enhance significantly the safety of the blood supply.

This agreement and a similar agreement with the American Red Cross announced earlier this year establish Chiron, through its alliance with Gen-Probe, as the leading supplier of investigational nucleic acid amplification technology to U.S. blood banks.

This investigational new system utilizes Transcription-Mediated Amplification (TMA), a state-of-the-art technology for nucleic acid testing (NAT) developed by Gen-Probe, and marketed by Chiron. Starting April 1, multiple ABC member laboratories will begin using the TMA system to test blood donor samples for infectious viruses, specifically the hepatitis C virus (HCV) and human immunodeficiency virus (HIV-1).

"We hope that through this agreement with America's Blood Centers, we can help make the U.S. blood supply even safer," said Rajen Dalal, president of Chiron's blood testing business. "The TMA system from Chiron and Gen-Probe allows blood centers to test for HCV and HIV simultaneously. Adoption of TMA may permit blood centers to move away from pooling of donor samples and initiate single donor nucleic acid screening. This important advance will have a significant impact on blood centers' ability to utilize nucleic acid testing to improve the efficiency and speed of current blood testing protocols," he added.

Researchers have demonstrated that TMA technology efficiently amplifies the nucleic acids of virus particles to allow direct detection before the body has developed antibodies to the virus. This provides earlier and more sensitive identification of potential virus particles in the blood stream than do current tests, which rely on antibody or viral protein detection. Antibodies to these viruses are formed in response to the infectious agents and take time to develop -- as long as 22 days for HIV and up to 80 days or more for HCV -- according to the New England Journal of Medicine (1996;334(26). TMA technology has the potential to reduce the time to detection, or the "window period," by about 50 percent for HIV and by 70 percent or more for HCV.

"We are very pleased to work with Chiron and Gen-Probe in this important research endeavor. In the 60-year history of blood banking, I am not aware of a task more sophisticated and complex than introducing NAT to blood screening. NAT is the most powerful testing technology available and holds the promise of allowing blood banks to virtually prevent transmission of any known virus and to detect any new potential threat to the blood supply," said Jim MacPherson, ABC executive director.

Chiron, Gen-Probe, and ABC are co-sponsors of FDA-regulated studies designed to evaluate the performance of TMA technology, and to demonstrate the effectiveness of nucleic acid testing for improving the safety of donated blood and blood products. Under the agreement, Chiron and Gen-Probe will supply instrumentation and reagent kits to ABC, which will conduct this testing at multiple centers nationwide. This testing is currently being performed under investigational protocols, and therefore the ultimate cost to blood centers and hospitals is not yet established. Additional terms of the agreement were not disclosed.

"We are very proud and enthusiastic about our partnership with America's Blood Centers," said Henry Nordhoff, president and chief executive officer of Gen-Probe, Incorporated. "The Gen-Probe amplified nucleic acid test, which directly detects the AIDS and hepatitis C viruses, will usher in a new era of blood testing worldwide!"

About America's Blood Centers

America's Blood Centers (ABC) is a national network of non-profit, independent community blood centers that provide almost half (47%) of the U.S. blood supply. ABC members serve about 125 million people in 45 states at more than 450 blood donation-sites. ABC members also provide more diagnostic and therapeutic services than any other U.S. blood organization. For more information, please see www.americasblood.org.

About Chiron Corporation

Chiron Corporation, headquartered in Emeryville, California, is a leading biotechnology company that participates in three global healthcare markets: therapeutics, blood testing and vaccines. Chiron also conducts research and development in the fields of recombinant technology, vaccines, gene therapy, small molecule discovery and genomics. Chiron's blood testing division also manufactures RIBA confirmatory tests, as well as hepatitis and retroviral antigens. For more information, visit the company's website at www.chiron.com.

About Gen-Probe Incorporated

Gen-Probe, Incorporated, a San Diego-based company, is a recognized world leader in the development, manufacture and commercialization of diagnostic products based on its patented genetic probe technologies. The company has received 40 FDA clearances for genetic probe tests to detect a wide range of microorganisms, including those causing sexually transmitted disease, tuberculosis, strep throat, pneumonia and fungal infections. The company is a wholly owned subsidiary of Chugai Pharmaceutical Co., Ltd., a major pharmaceutical company in Japan. For more information, visit the company's web-site at www.gen-probe.com.