Therapeutic immunization with a human immunodeficiency virus (HIV) type 1-recombinant canarypox vaccine in chronically HIV-infected patients: The Vacciter Study (ANRS 094)

This open single-arm study evaluated whether the administration of an HIV-recombinant canarypox vaccine (vCP1433) in highly active antiretroviral therapy (HAART)-treated patients chronically infected with HIV was safe, immunogenic and associated with prolongation of treatment discontinuation: 48 patients received four monthly vCP1433 injections and stopped HAART. Immunization was safe. HIV-p24-specific lymphoproliferative responses (LPR), significantly increased in the whole group after two injections but decreased thereafter, HIV-gag-specific CD8 T cells were boosted in 55% patients tested. Altogether, 11% patients with at least one HIV-specific LPR during immunization remained off therapy after 44 weeks of interruption. Detection of such LPR response at the time of treatment interruption was significantly associated with the probability of remaining off therapy. These results provide rationale for future randomized trials exploring this strategy.