The need for an effective Respiratory Syncytial virus (RSV) vaccine for both young children and the
elderly has long been recognized. In individuals >65 years old, the CDC estimates that RSV accounts
for ~11,000 deaths and ~177,000 hospitalizations annually in the US. The large burden of RSV disease
in the expanding elderly population alone makes the development of an RSV vaccine extremely warranted.
The major protective immunogen for RSV is the F glycoprotein. Alphavaccine VRP vaccines expressing
the F glycoprotein have been shown in published studies to be highly immunogenic in mice, cotton rats
and non-human primates. F-VRP immunization also conferred complete protection against lower respiratory
tract infection in murine and cotton rat RSV-challenge models. Observational studies in humans have
indicated that higher serum neutralizing antibodies to RSV are beneficial.
Based on these positive pre-clinical studies using the alphavaccine system for the prevention of RSV,
we are advancing an RSV-F vaccine toward phase I clinical testing by the second quarter of 2010. The
initial Phase II testing of this candidate will be pursued in an elderly population.