Court Grants Chiron Right to Enjoin Roche From Selling HCV Immunodiagnostic Products in Germany.

EMERYVILLE, Calif.--(BW HealthWire)--April 29, 1999--

Chiron Corporation (NASDAQ: CHIR) announced today that a German court has ruled that Chiron is entitled to an injunction prohibiting Hoffman La Roche AG (Roche) from selling its hepatitis C virus (HCV) immunoassays in Germany. The District Court of Dusseldorf determined that Chiron's European HCV patent No. 0 318 216 was infringed by Roche's immunoassays which are used for detecting the presence of HCV in blood.

The German court rejected the defenses offered by Roche, including its assertion that it was entitled to an ownership interest in Chiron's `216 patent by virtue of a purported assignment of rights to Roche by Daniel Bradley, a former employee of the U.S. Centers for Disease Control. Although the court did not find that Bradley ever had rights in Chiron's HCV patents, the court did rule that any rights he may have had were previously released and assigned to Chiron. Additionally, the court rejected Roche's defense based upon an assertion that Chiron abused a dominant position in the German HCV immuno market. The court's order is subject to appeal and is limited to infringing activity in Germany.

"The ruling of the German court is a significant development in Chiron's ongoing efforts to protect its HCV patent portfolio rights against infringers," commented William Green, Chiron senior vice president and general counsel. "Roche appears to have mounted an exhaustive defense, which the court has rejected, including issues that extend beyond the immunodiagnostic products found to be infringing in this case. The court's action further affirms the strength of our proprietary position in this important diagnostic area."

Chiron scientists cloned HCV in 1987 following five years of research. This discovery marked the first time a virus was cloned before it had been grown in tissue culture or otherwise isolated. Since the initial discovery, Chiron has been granted more than 100 HCV-related patents in over 20 countries. Chiron's `216 patent covers structural and non-structural antigenic HCV polypeptides produced by any method, HCV antibodies, and the use of such polypeptides and antibodies in immunoassays.

Chiron Corporation, headquartered in Emeryville, California, is a leading biotechnology company that participates in three global healthcare markets: biopharmaceuticals, blood testing, and vaccines. The company is applying a broad and integrated scientific approach to the development of innovative products for preventing and treating cancer, infectious diseases, and cardiovascular diseases. This approach is supported by research strengths in recombinant proteins, genomics, small molecules, gene therapy, and vaccines. For more information, visit the company's website at www.chiron.com.

This document contains forward-looking statements that are subject to risk and uncertainty. There are a number of factors that could cause the company's actual performance to differ materially from expectations. These and other factors investors should consider are more thoroughly described in the company's Securities and Exchange Commission filings, including the Form 10-Q and Form 10-K.