ACAMBIS RELEASES RESULTS PHASE II STUDY OF SMALLPOX VACCINE

Acambis has announced preliminary results from a Phase II trial of its modified vaccinia ankara smallpox vaccine, MVA3000. Acambis is co-developing MVA3000 with Baxter Healthcare, which is providing process development and manufacturing services.

MVA3000 is an attenuated smallpox vaccine that is being developed for use in people for whom the traditional smallpox vaccine is contraindicated, such as patients with disorders of the immune system or skin conditions such as eczema. Acambis was awarded contracts by the National Institute of Allergy and Infectious Disease for the manufacture of MVA3000 and a series of Phase I and II trials.

In total, 590 healthy adult subjects were enrolled in this randomized, double-blind, placebo-controlled trial, which tested multiple dose levels of MVA3000 against placebo. Of the enrolled subjects 361 had never received a smallpox vaccine, and 229 had previously been vaccinated against smallpox.

In vaccine-naive subjects vaccinated at the highest dose level, immunogenicity results were consistent with the findings from the Phase I trial with 75 percent of subjects seroconverting after two doses. In previously vaccinated subjects, 88 percent of subjects vaccinated at the highest dose level seroconverted after two doses. The neutralizing antibody levels necessary to protect against smallpox are unknown.