A randomized, double-blind, dose-finding Phase II study to evaluate immunogenicity and safety of the third generation smallpox vaccine candidate IMVAMUNE.

IMVAMUNE is a Modified Vaccinia Ankara (MVA)-based virus that is being developed as a safer 3rd generation smallpox vaccine. In order to determine the optimal dose for further development, a double-blind, randomized Phase II trial was performed testing three different doses of IMVAMUNE in 164 healthy volunteers. All three IMVAMUNE doses displayed a favourable safety profile, with local reactions as the most frequent observation. The 1 x 10(8)TCID(50) IMVAMUNE dose induced a total antibody response in 94% of the subjects following the first vaccination and the highest peak seroconversion rates by ELISA (100%) and PRNT (71%). This IMVAMUNE dose was considered to be optimal for the further clinical development of this highly attenuated poxvirus as a safer smallpox vaccine.