April 7, 2008

Avant released positive results from a phase II trial of Ty800, a vaccine for the treatment of Typhoid Fever. This randomized, placebo-controlled, double-blind, dose-ranging trial enrolled one hundred and eighty three healthy, adult subjects in the United States. The subjects received Ty800 1x10(8) or 1x10(9) colony-forming units (CFUs) or placebo and were followed for six months post-vaccination. The primary endpoints were to determine the optimal dose of Ty800 for further development based on safety, reactogenicity, and immunogenicity. Immunogenic response was dose-dependent. Positive immune response or seroconversion (prospectively defined as a 4-fold increase in anti-LPS titers over pre-dose level) rates were 65.5% and 80% in the low and high dose groups, respectively, and was significantly higher than placebo (p less than 0.001). Ty800 was well tolerated, with the incidence of reactogenicity symptoms and adverse events post-vaccination similar to placebo. Based on the results, Avant plans to move the development of the vaccine forward.

May 28, 2007

Avant released positive preliminary results from a phase I/II trial of Ty800, a vaccine for the prevention of Typhoid Fever. This double-blind, placebo-controlled, dose escalating trial enrolled 47 healthy subjects who were randomized to receive one of three doses of Ty800: 8x10(7), 6x10(8) and 1x10(10) colony-forming units (CFU) or placebo. Subjects were than followed for six months. The dose of 6x10(8) CFU appeared to be immunogenic with similar reactogenicity as placebo. In addition, over 90% of subjects receiving the vaccine showed positive immune responses for both systemic (IgG) and mucosal (IgA) antibodies to typhoid based on an ELISPOT assay. Based on the results, Avant plans to initiate a phase II trial by mid-2007.