H5 Adult - Chiron Study of Bird Flu Vaccine

Overview

This study is will gather critical information on the safety, tolerability, and the immunogenicity (capability of causing an immune response) of A/H5N1 (Bird flu) virus vaccine in healthy adults. Up to 400 healthy adults, aged 18 to 64, will participate. Each subject will participate for about 7 months and will be randomly placed in one of several different study groups receiving a different dose of vaccine or placebo. All subjects will receive two injections of their assigned study product, about 28 days apart, in the muscle. Subjects will keep a journal of their temperature and any adverse effects between study visits. A small amount of blood will also be drawn before the first injection, 7 days after each injection, 1 month after the first injection, and 1 and 6 months after the second injection.

The emergence of novel influenza A virus strains in humans (including subtype A/H5N1, H7N7 H9N2 viruses) has added urgency to ongoing efforts to develop plans for responding to potential pandemic situations. This study compares the safety, reactogenicity, and immunogenicity of increasing doses of monovalent subvirion influenza A/H5N1 virus vaccine administered by intramuscular (IM) injection to healthy adults alone or combined with the adjuvants aluminum hydroxide or MF59. The primary objectives are to determine: the dose-related safety of subvirion inactivated H5N1vaccine with and without adjuvants in healthy adults; the dose-related immunogenicity of subvirion inactivated H5N1vaccine with and without adjuvants in healthy adults approximately 1 month following receipt of 2 vaccine doses; to provide information for the selection of the best dosage level for further studies. The secondary objectives are to evaluate dose-related immunogenicity and the percent of subjects responding about 1 and 7 months after the first vaccination. The primary endpoints are: adverse event (AE) or serious adverse event (SAE) information; proportion of subjects in each dose group achieving a serum neutralizing antibody titer of 1:40 against the influenza A/H5N1 virus 28 days after receipt of the second dose of vaccine; proportion of subjects in each dose group achieving a serum hemagglutination (HAI) antibody titer of 1:40 against the influenza A/H5N1 virus 28 days after receipt of the second dose of vaccine; geometric mean titer (GMT) and frequency of 4-fold or greater increases in neutralizing antibody titers in each group 28 days after receipt of the second dose of vaccine; geometric mean titer and frequency of 4-fold or greater increases in serum HAI antibody titers in each group 28 days after receipt of the second dose of vaccine. The secondary endpoints are: GMT and frequency of 4-fold or greater increases in neutralizing antibody titers in each group 1 month and 7 months after receipt of the first dose of vaccine; geometric mean titer and frequency of 4-fold or greater increases in serum HAI antibody titers in each group 1 month and 7 months after receipt of the first dose of vaccine; development of serum antibody responses against antigenically drifted variants of H5N1 influenza virus. The primary outcome measures will be the frequencies and severities of AEs in each group and the proportions of subjects who achieve a serum neutralizing antibody titer of 1:40 against the influenza A/H5N1 virus on Day 56. About 390 healthy adults, 18 to 64 years old, inclusive, will be enrolled into this multicenter, randomized, placebo-controlled, dose-ranging clinical trial. Nine groups of randomized subjects will receive two doses of saline placebo or influenza A/H5N1 vaccine at 45, 30, or 15 micrograms; or influenza A/H5N1 vaccine at 15 or 7.5 micrograms with MF59; or influenza A/H5N1 vaccine with aluminum hydroxide at 30, 15, or 7.5 micrograms (N=30, 60 or 90/vaccine dose group total 390). Laboratory safety profile blood will be drawn prior to the first immunization. Subjects will receive 2 doses approximately 28 days apart. Subjects will be observed after inoculation and maintain a memory aid for 7 days afterwards. Subjects will be telephoned 1 to 3 days after vaccination for AE assessment, and they will return to the clinic on Day 7 for AE and concomitant medication assessment, targeted physical examination, safety laboratory tests and a review of the memory aid. Telephone calls assessing AEs will be performed after each vaccination. Serum for safety laboratory tests will be obtained prior to and approximately 7 days after first and second immunizations. I