A phase I double blind, placebo-controlled, randomized study of a multigenic HIV-1 adenovirus subtype 35 vector vaccine in healthy uninfected adults.

Publication Type
Journal Article
Year of Publication
Keefer, Michael C; Gilmour, Jill; Hayes, Peter; Gill, Dilbinder; Kopycinski, Jakub; Cheeseman, Hannah; Cashin-Cox, Michelle; Naarding, Marloes; Clark, Lorna; Fernandez, Natalia; Bunce, Catherine A; Hay, Christine M; Welsh, Sabrina; Komaroff, Wendy; Hachaambwa, Lottie; Tarragona-Fiol, Tony; Sayeed, Eddy; Zachariah, Devika; Ackland, James; Loughran, Kelley; Barin, Burc; Cormier, Emmanuel; Cox, Josephine H; Fast, Patricia; Excler, Jean-Louis
PLoS One
Date Published
Adenoviruses, Human; Adolescent; Adult; AIDS Vaccines; Antibodies, Viral; CD4-Positive T-Lymphocytes; CD8-Positive T-Lymphocytes; Dose-Response Relationship, Immunologic; Double-Blind Method; Female; HIV Infections; HIV-1; Humans; Immunity, Cellular; Immunity, Humoral; Male; Middle Aged; Retroviridae Proteins; Vaccination

BACKGROUND: We conducted a phase I, randomized, double-blind, placebo-controlled trial to assess the safety and immunogenicity of escalating doses of two recombinant replication defective adenovirus serotype 35 (Ad35) vectors containing gag, reverse transcriptase, integrase and nef (Ad35-GRIN) and env (Ad35-ENV), both derived from HIV-1 subtype A isolates. The trial enrolled 56 healthy HIV-uninfected adults.

METHODS: Ad35-GRIN/ENV (Ad35-GRIN and Ad35-ENV mixed in the same vial in equal proportions) or Ad35-GRIN was administered intramuscularly at 0 and 6 months. Participants were randomized to receive either vaccine or placebo (10/4 per group, respectively) within one of four dosage groups: Ad35-GRIN/ENV 2×10(9) (A), 2×10(10) (B), 2×10(11) (C), or Ad35-GRIN 1×10(10) (D) viral particles.

RESULTS: No vaccine-related serious adverse event was reported. Reactogenicity events reported were dose-dependent, mostly mild or moderate, some severe in Group C volunteers, all transient and resolving spontaneously. IFN-γ ELISPOT responses to any vaccine antigen were detected in 50, 56, 70 and 90% after the first vaccination, and in 75, 100, 88 and 86% of Groups A-D vaccine recipients after the second vaccination, respectively. The median spot forming cells (SFC) per 10(6) PBMC to any antigen was 78-139 across Groups A-C and 158-174 in Group D, after each of the vaccinations with a maximum of 2991 SFC. Four to five HIV proteins were commonly recognized across all the groups and over multiple timepoints. CD4+ and CD8+ T-cell responses were polyfunctional. Env antibodies were detected in all Group A-C vaccinees and Gag antibodies in most vaccinees after the second immunization. Ad35 neutralizing titers remained low after the second vaccination.

CONCLUSION/SIGNIFICANCE: Ad35-GRIN/ENV reactogenicity was dose-related. HIV-specific cellular and humoral responses were seen in the majority of volunteers immunized with Ad35-GRIN/ENV or Ad35-GRIN and increased after the second vaccination. T-cell responses were broad and polyfunctional.

TRIAL REGISTRATION: ClinicalTrials.gov NCT00851383.