Chiron to Release More Sensitive Quantiplex HIV-1 Viral Load Test to Research Laboratories and Chiron Reference Testing Laboratory.

EMERYVILLE, Calif.--(BUSINESS WIRE)--June 30, 1998--Chiron Diagnostics, a business of Chiron Corporation (NASDAQ:CHIR), announced it will begin releasing the branched DNA (bDNA) Quantiplex(R) HIV-1 RNA 3.0 assay to research laboratories and Chiron's Reference Testing Laboratory (CRTL) this summer. This assay is for research use only.

The Quantiplex HIV-1 RNA 3.0 assay offers improved sensitivity, quantifying as little as 50 copies/mL and a broad dynamic range (50 to 500,000 copies/mL) that eliminates the need for reflex testing. With other unique features including system automation and accurate quantification across HIV-1 subtypes A-F, the Quantiplex HIV-1 RNA 3.0 assay combines a high level of sensitivity with traditional performance benefits associated with bDNA technology.

"With the advent of more effective antiretroviral therapies, there is a demand for even more sensitive assays capable of quantifying very low levels of HIV-1," said Dr. Mickey Urdea, senior vice president, Nucleic Acid Diagnostics. "We've improved the probe design, increased the number of probes, and integrated a new method for reducing assay background. This has resulted in an assay with an amazing level of sensitivity."

The Quantiplex HIV-1 RNA 3.0 assay runs on the Chiron Quantiplex 340 Automated bDNA System. This new automated system represents a significant advance in the quantification of viral load measurements. By automating previously labor intensive steps in assay processing, the system reduces labor requirements, improves assay performance, and increases laboratory efficiencies. With a throughput up to 168 samples per run, the Quantiplex 340 Automated bDNA System meets the needs of both high- and low-volume laboratories.

Chiron's bDNA technology utilizes unique, DNA synthetic probes to directly measure viral RNA and DNA from individuals infected with HIV, Hepatitis C, and Hepatitis B. Viral load measurement enables researchers to evaluate disease progression and assess candidate therapies for disease treatment. bDNA technology provides a direct measurement of virus at physiological levels eliminating the need for dedicated testing areas required by target amplification methods.

Chiron Diagnostics Corporation combines biotechnology, chemistry and advanced systems to empower physicians with information to better manage therapies and help patients understand their disease. Chiron Diagnostics has operations in 20 countries, sells its products in more than 90 countries and employs approximately 3,000 people. Its products include automated instrumentation, reagents, controls, and nucleic acid systems to quantify viral load. Chiron Diagnostics focuses its advanced diagnostics technologies in Critical Blood Analysis, Clinical Chemistry, Endocrinology, Infectious Disease, Allergy, and Oncology.

Chiron Corporation, headquartered in Emeryville, California, is a leading biotechnology company that participates in three global healthcare markets: diagnostics, therapeutics and vaccines. Chiron also conducts research and development in the fields of biological proteins, gene therapy and combinatorial chemistry.

This news release contains forward-looking statements that involve risks and uncertainties which might affect the initiation and completion of clinical trials and the launch of products. A full discussion of the companies' operations and financial condition, including factors that may affect their business and future prospects, is contained in documents the companies file with the SEC, such as form 10-Q and 10-K and 40F reports. These documents identify important factors that could cause the companies' actual performance to differ from current expectations, including the outcome of clinical trials, regulatory review, manufacturing capabilities and marketing effectiveness.

    CONTACT: Chiron Corporation
              Victoria DeMoranville, 508-660-4581