The Search for a Safer Smallpox Vaccine Reveals New Data on a Promising Candidate

ST. LOUIS -- When used as an aerosolized weapon, smallpox could be controlled by a new vaccine under study at Saint Louis University School of Medicine, according to new data.

Detailed results from studies by Dr. Mark Buller of Saint Louis University School of Medicine were presented at the Seventh Annual Conference on Vaccine Research, sponsored by the National Foundation for Infectious Diseases, in Arlington, Va. The research tested the efficacy of a smallpox vaccine candidate known as LC16m8.

The research conducted at Saint Louis University by Buller and his colleagues has demonstrated that the vaccine, given to mice, protects against a virus related to smallpox that has been aerosolized. According to Buller, this closely models how smallpox could be delivered during a bioterrorist attack.

Buller and his colleagues, working in accordance with VaxGen and the National Institutes of Health, are working to make sure that the U.S. develops safer smallpox vaccines. The National Institute of Allergy and Infectious Diseases, a part of the National Institutes of Health, funded the study.

Buller said that although smallpox was eradicated from human populations in 1977 by vaccination, the vaccine had a poor safety profile and caused life-threatening diseases in a small, but significant proportion of the US population.

"The threat of bioterrorism necessitates the development of new and safer vaccines and treatments against likely threat agents," Buller said.

The smallpox vaccine candidate, LC16m8, has been licensed for use in Japan since 1980. The live vaccine is produced in a cell culture from vaccinia virus that has been attenuated, or modified, so that it can initiate an immune response without causing serious adverse side effects. LC16m8 is designed to have a better safety profile, yet be equally effective, compared to conventional smallpox vaccines.

Buller's research is one of two research studies conducted to support the efficacy of the smallpox vaccine. VaxGen, Inc., a biopharmaceutical company engaged in the development, manufacturing and commercialization of biologic products for the prevention and treatment of human infectious diseases, funded the other research study.

"The positive results of both studies suggest that additional studies are warranted to further evaluate the efficacy of the vaccine candidate," Buller said.

VaxGen plans to begin a Phase I/II trial in humans later this year to study LC16m8's safety and ability to induce an immune response. VaxGen also intends to initiate a large-scale safety trial in the second half of 2004. Additional pre-clinical studies are also planned.

Source: Saint Louis University Health Sciences Center