Chiron and Canadian Collaborators Announce Publication of Promising Phase II Results for Novel Meningoccus C Vaccine.

EMERYVILLE, Calif.--(BW HealthWire)--Nov. 17, 1998--

Clinical Trial Results Demonstrate Well-Tolerated, Effective and

Long-Lasting Immune Response in Children to Novel Vaccine for

Prevention of Meningitis; Article in JAMA 

Chiron Corporation (Nasdaq:CHIR) today announced the publication of the Phase II clinical trial data for its conjugate vaccine against Meningoccus C (MenC).

The results from the trial, conducted at the University of Ottawa (Ottawa, Canada), Dalhousie University (Halifax, Canada) and the University of Manitoba (Winnipeg, Canada), were reported in the Nov. 18, 1998, issue of the Journal of the American Medical Association.

Meningoccus meningitis is a serious bacterial disease that causes severe morbidity and mortality in children who contract it. The MenC strain, which accounts for approximately forty-five percent of the cases in North America, predominantly affects toddlers and infants and is considered a serious health issue worldwide. Though currently available, MenC polysaccharide vaccines are not used routinely for infants and toddlers. This is due to concerns about low immune responses and the lack of efficacy of these polysaccharide vaccines in young children, as well as the possibility of decreasing the recipient's ability to respond to a subsequent vaccination.

Promising Conjugate Vaccine Candidate

The results of the Phase II study indicate that Chiron's MenC conjugate vaccine is safe, highly immunogenic and creates long-lasting immunity. The trial was a blinded, controlled, randomized, multi-center study involving over 200 toddlers. Participants were administered two injections, two months apart of either Chiron's MenC vaccine or a meningococcal polysaccharide vaccine licensed in the U.S. and Canada. The control group received a hepatitis B vaccine. All toddlers received a 12-month follow-up dose of the polysaccharide vaccine. Antibody levels were evaluated before the first vaccination and at two, three, fourteen and fifteen months after the initial inoculation.

After the first dose, antibody levels were four-times higher with the Chiron vaccine than with the conventional meningococcal vaccine. The levels were 10-times higher with the Chiron vaccine after the second dose. This performance difference persisted over time as measured at the 12-month follow-up point. No vaccine-related serious adverse side effects were observed during the study and all three vaccines were well tolerated.

"Meningococcal C is a deadly disease that physicians would clearly prefer to prevent rather than treat since the morbidity and mortality rates are high," said Noni E. MacDonald, M.D., principal investigator and chief of the division of infectious diseases at Children's Hospital of Eastern Ontario. "The excellent antibody responses to the Chiron vaccine in this clinical study hold promise that this vaccine will allow control and prevention of this dreaded disease in young children."

Chiron is currently conducting a pivotal Phase III trial for its MenC vaccine in the United Kingdom. The trial is expected to be complete next year.

"We are encouraged by the efficacy and safety demonstrated by our conjugate MenC vaccine in the Phase II study," said Magnus Lundberg, president of Chiron Vaccines and Chiron Therapeutics. "Meningococcal meningitis is a deadly disease and we are committed to developing an effective and safe vaccine. Our next steps involve completing a Phase III study and pursuing necessary regulatory action with the goal of bringing the vaccine to market."

About Meningococcal Meningitis

According to the World Health Organization, meningococcal meningitis is the only form of bacterial meningitis that causes epidemics. Meningococcal disease is characterized by a sudden onset of headache, fever, nausea, vomiting and stiff neck. Even with antibiotic therapy, mortality rates average ten percent in the U.S. and Europe, and even higher in developing countries. Recognizing the need for an effective vaccine, the United Kingdom is proposing to mandate universal immunization of infants, and subsequently wants to have all individuals under age twenty-one inoculated.

About the Company

Chiron uses its expertise in recombinant technology, gene delivery and adjuvants, which enhance a vaccine's effectiveness, to develop innovative vaccines for adults and children. The company, which sells a variety of novel and conventional vaccines products worldwide, is a market leader in Germany and Italy. Chiron also sells its products to multinational healthcare organizations and to local distributors internationally.

Headquartered in Emeryville, California, Chiron is a leading biotechnology company that participates in three global healthcare markets: therapeutics, vaccines and blood testing. Chiron also conducts research and development in the fields of recombinant technology, gene therapy, vaccines, small molecule discovery, and genomics.

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