Comparative Safety and Immunogenicity of VAX128A, VAC128B and VAX128C Novel H1N1 Influenza Vaccine in Healthy Adults

VAX128-01 is a first in human study of three inactivated recombinant novel H1N1 influenza
vaccines, designated VAX128 A, B and C. The purpose of the study is to compare the safety
and immunogenicity of the three vaccines through a range of doses and to select one of the
vaccines for further testing in phase II studies. We plan to assess the safety and
immunogenicity in a dose escalating study. The study will enroll up to 100 healthy young
adults (18-49 years) and 100 healthy adults than age 65 years. We are including the older
adults in this phase 1 study because we have found that the elderly tolerated a vaccine
similar to one of the candidates, VAX128A, better than young adults, but required a higher
vaccine dose to achieve a similar antibody response. Nevertheless, because we are testing
two other constructs (VAX128B and C), we will be making the conservative assumptions that
the safety and immunogenicity data coming from the young adults will not predict the results
in the elderly. Therefore, we will begin the study in the young adults and after the first
three dose levels have been tested we will begin testing in the older adults. In this study
we plan to enroll up to 100 young adults and up to 100 adults 65 years and older. The young
adults will be most likely enrolled at one clinical site and the older adults will be
enrolled at another clinical site. We plan to enroll a cohort of 10 young adults and 10
older adults every week. Each cohort will consist of 3 subjects to receive one of the three
vaccines (9 subjects total) and one subject in each cohort will receive placebo. Dosing for
the next cohort will be based on a two day assessment period after vaccination. The main
part of the study will be conducted over 28 days and there will be two follow up phone calls
at 6 months and one year.