Chiron Corp. is planning to begin a Phase III registration trial in the U.S. to study its Menjugate conjugated vaccine for the prevention of meningococcal C disease.

The company expects to begin the trial during the first half of this year, though protocol details are not being disclosed as discussions continue with the FDA. Chiron said the study would end the following year.

The Emeryville, Calif.-based company is working to reduce meningococcal infection through development of vaccines for five key serogroups that cause it - A, B, C, Y and W-135. Chiron said an estimated 150 million people worldwide would benefit from a catch-up campaign for preventive vaccines against meningococcal disease.

"We would anticipate that the vaccine would be used for outbreaks, and there have been several in the U.S.," Alison Marquiss, Chiron's associate manager of corporate communications and investor relations, told BioWorld Today. "In that sense it's an important, unmet medical need. But recommendations for vaccines are certainly the territory of groups such as the Advisory Committee on Immunization Practices [a unit of the Centers for Disease Control and Prevention in Atlanta]."

The bacterium Neisseria meningitidis is the leading cause of meningococcus worldwide, resulting in an estimated 120,000 cases of bacterial meningitis and sepsis annually. Chiron said that figure includes 3,000 U.S. cases each year, which result in a fatality rate that ranges between 10 percent and 15 percent. Among survivors, an additional 11 percent to 19 percent develop significant sequelae, including neurologic disability, limb loss or hearing loss.

Menjugate already is approved for use in infants through adults in 24 countries. In vaccination campaigns in the UK and Quebec, Chiron said the vaccine has helped reduce deaths from meningococcal C disease by 80 percent.

In Canada, the Quebec Ministry of Health paid C$75 million (US$48.8 million) to Chiron and its distributor, Kirkland, Quebec-based Merck Frost Canada Ltd., for about 1.7 million doses. (See BioWorld Today, July 19, 2001.)

A little more than a year before, Chiron received a license to market the product in the UK, which sought to implement a national immunization program against meningococcal disease.

"The vaccine confers an immunological memory against the bacteria," Marquiss said. "Most current vaccines are polysaccharides, a sugar response to the serogroups. But with our conjugate, we link that sugar to a diphtheria protein in order to create the immune response. It's a nontoxic mutant of the diphtheria protein."

Results of a U.S.-based Phase I trial of a recombinant meningococcal B vaccine are under evaluation and could be released by the end of the year, Marquiss said. The study is designed to assess the vaccine's effectiveness against a broad strain of meningococcus B.

Clinical trials in New Zealand also are under way to test a vaccine specific to the strain of meningococcus B endemic in that country. According to the company, no broad-coverage vaccine exists to prevent meningococcal B infection.

In addition, Chiron has a combination vaccine against serogroups A, C, Y and W-135 in development. The company continues to evaluate data from a completed Phase I trial of the vaccine, but would release no further details.

Outside of Menjugate, Chiron markets more than 30 vaccines for adults and children. Among its offerings are Fluad, an adjuvanted flu vaccine; Begrivac, a preservative-free flu vaccine; and Encepur, a vaccine against tick-borne encephalitis. Marquiss said Chiron has in preclinical development HIV and hepatitis C vaccines, both being advanced in partnership with the National Institutes of Health in Bethesda, Md.

Beyond its vaccine business, Chiron focuses on biopharmaceuticals and blood testing.

Its therapeutic product lineup includes TOBI (tobramycin solution for inhalation) for lung infections in cystic fibrosis patients, Proleukin (aldesleukin) for kidney and skin cancer and Betaseron (interferon beta-1b) for multiple sclerosis, which is marketed by Berlex Laboratories Inc., the U.S. subsidiary of Berlin-based Schering AG.

Tifacogin, a recombinant human tissue growth factor pathway inhibitor, is in Phase III development with Peapack, N.J.-based Pharmacia Corp. for sepsis. In Phase II programs, Chiron is developing tezacitabine for gastroesophageal cancers and Angiozyme (anti-angiogenic ribozyme) for colorectal cancer, the latter in partnership with Boulder, Colo.-based with Ribozyme Pharmaceuticals Inc. Its Proleukin product is in a number of Phase I and II studies for other types of cancer, while tezacitabine also is in a Phase I study for colorectal cancer.

Its blood testing business has produced NAT (nucleic acid testing) blood screening assays in conjunction with its partner, San Diego-based Gen-Probe Inc., including the Procleix HIV-1/HCV assay. Through a joint business with Ortho-Clinical Diagnostics, a unit of New Brunswick, N.J.-based Johnson & Johnson, Chiron develops and markets a line of immunoassay screening and supplemental tests for infectious disease.

Chiron's stock (NASDAQ:CHIR) rose 88 cents Thursday to close at $36.24.