Immunogenicity & Safety of GSK's Influenza Vaccine 1557484A Given to Adults Aged ≥18 Years

• HI antibody titer for younger adults age 18 to 64 years and older adults age >64 years [ Time Frame: At 21 days after the second dose of GSK 1557484A vaccine ] [ Designated as safety issue: No ]
• The occurrence of specifically-solicited local and general signs and symptoms, and overall per subject considering both post-immunization periods [ Time Frame: During a 7-day follow-up period (i.e., day of vaccination and 6 subsequent days) after each vaccine administration ] [ Designated as safety issue: No ]
• The occurrence of all unsolicited adverse events [ Time Frame: During a 21-day follow-up period for each vaccine administration, as well as overall (Day 0 through Day 84) ] [ Designated as safety issue: No ]
• The occurrence of serious adverse events and medically-attended events [ Time Frame: Day 0 through Day 182. ] [ Designated as safety issue: No ]

• HI antibody titer for younger adults age 18 to 64 years and older adults age >64 years [ Time Frame: At 21 days after the second dose of GSK 1557484A vaccine ]
• The occurrence of specifically-solicited local and general signs and symptoms, and overall per subject considering both post-immunization periods [ Time Frame: During a 7-day follow-up period (i.e., day of vaccination and 6 subsequent days) after each vaccine administration ]
• The occurrence of all unsolicited adverse events [ Time Frame: During a 21-day follow-up period for each vaccine administration, as well as overall (Day 0 through Day 84) ]
• The occurrence of serious adverse events and medically-attended events [ Time Frame: Day 0 through Day 182. ]

• HI antibody titer for younger adults age 18 to 60 years and older adults age >60 years [ Time Frame: At 21 days after the second dose of GSK 1557484A vaccine ] [ Designated as safety issue: No ]
• HI antibody titer for younger adults age 18 to 64 years and older adults age >64 years. [ Time Frame: At 6 months after the first dose of GSK 1557484A vaccine ] [ Designated as safety issue: No ]
• Vaccine-homologous virus and drift variant H5N1 virus antibody responses, as assessed by microneutralization assays, in subjects receiving 2 doses of study vaccine. [ Designated as safety issue: No ]

• HI antibody titer for younger adults age 18 to 60 years and older adults age >60 years [ Time Frame: At 21 days after the second dose of GSK 1557484A vaccine ]
• HI antibody titer for younger adults age 18 to 64 years and older adults age >64 years. [ Time Frame: At 6 months after the first dose of GSK 1557484A vaccine ]
• Vaccine-homologous virus and drift variant H5N1 virus antibody responses, as assessed by microneutralization assays, in subjects receiving 2 doses of study vaccine.

The purpose of this Phase 3, observer-blind, placebo-controlled, multi-center study is to characterize the immunogenicity & safety of the investigation vaccination regimen of GSK 1557484A vaccine given to adults aged ≥18 years.

• Influenza Disease Caused by an Influenza A Virus
• Influenza Vaccines

• Biological: GSK 1557484A
  Two intramuscular injections.
• Biological: Placebo
  Two intramuscular injections.

• Experimental: Group A
  Subjects aged 18-49 years will receive the investigational GSK 1557484A vaccine formulation A.
  Intervention: Biological: GSK 1557484A
• Experimental: Group B
  Subjects aged 18-49 years will receive the investigational GSK 1557484A vaccine formulation B.
  Intervention: Biological: GSK 1557484A
• Experimental: Group C
  Subjects aged 18-49 years will receive the investigational GSK 1557484A vaccine formulation C.
  Intervention: Biological: GSK 1557484A
• Placebo Comparator: Group D
  Subjects aged 18-49 years will receive a placebo.
  Intervention: Biological: Placebo
• Experimental: Group E
  Subjects aged 50-64 years will receive the investigational GSK 1557484A vaccine formulations A. B, or C in approximately equal proportions.
  Intervention: Biological: GSK 1557484A
• Placebo Comparator: Group F
  Subjects aged 50-64 years will receive a placebo.
  Intervention: Biological: Placebo
• Experimental: Group G
  Subjects aged > 64 years will receive the investigational GSK 1557484A vaccine formulations A. B, or C in approximately equal proportions.
  Intervention: Biological: GSK 1557484A
• Placebo Comparator: Group H
  Subjects aged > 64 years will receive a placebo.
  Intervention: Biological: Placebo

Inclusion Criteria:

• A male or female 18 years of age or greater at the time of the first vaccination.
• Written informed consent obtained from the subject.
• Among 18 to 49 year old subjects, good general health as established by medical history and clinical examination before entering into the study.
• Among subjects > 49 years of age, stable health status within 1 month prior to enrollment.
• Access to a consistent means of telephone contact.
• Comprehension of the study requirements, ability to comprehend and comply with procedures for collection of short- and long-term safety data, expressed availability for the required study period, and ability and willingness to attend scheduled visits.

Exclusion Criteria:

• Evidence of substance abuse or of neurological or psychiatric diagnoses which, even if clinically stable, are deemed by the investigator to render the potential subjectunable/unlikely to provide accurate safety reports.
• Diagnosed with cancer, or treatment for cancer, within 3 years.
• An oral temperature ≥37.8º C, or acute symptoms greater than "mild" severity on the scheduled date of first vaccination.
• Any confirmed or suspected immunosuppressive or immunodeficient condition including history of human immunodeficiency virus infection.
• Receipt of systemic glucocorticoids within 1 month of study enrollment, or any other cytotoxic or immunosuppressive drug within 6 months of study enrollment.
• Any significant disorder of coagulation or treatment with Coumadin derivatives or heparin.
• Administration of any vaccines within 30 days before study enrollment.
• Previous administration of any H5N1 vaccine.
• Use of any investigational or non-registered product or planned participation in another investigational study within 30 days prior to study enrollment, or during the 364 days following the first test article dose. Use of any investigational or non-registered product with immunosuppressive properties is exclusionary at any time during the trial.
• Receipt of any immunoglobulins and/or any blood products within 3 months of study enrollment or planned administration of any of these products during the study period.
• Any known or suspected allergy to any constituent of influenza vaccines; a history of anaphylactic-type reaction to consumption of eggs; or a history of severe adverse reaction to a previous influenza vaccine.
• Known pregnancy or a positive urine beta-human chorionic gonadotropin test result prior to either vaccination.
• Lactating or nursing.
• Women of child bearing potential who lack a history of reliable contraceptive practices. The provision of this history does NOT replace the requirement to perform, and obtain negative results in pregnancy urine tests prior to treatments.
• Known use of an analgesic or antipyretic medication within 12 hours prior to first treatment.