A therapeutic HIV-1 vaccine enhances anti-HIV-1 immune responses in patients under highly active antiretroviral therapy

Vaccine. 2016 Apr 27;34(19):2225-32. doi: 10.1016/j.vaccine.2016.03.021. Epub 2016 Mar 19.


Background: HIV-1 specific cellular immunity plays an important role in controlling viral replication. In this first-in-human therapeutic vaccination study, a replication-defective HIV-1 vaccine (HIVAX) was tested in HIV-1 infected participants undergoing highly active antiretroviral therapy (HAART) to enhance anti-HIV immunity (Clinicaltrials.gov, identifier NCT01428596).

Methods: A010 was a randomized, placebo-controlled trial to evaluate the safety and the immunogenicity of a replication defective HIV-1 vaccine (HIVAX) given as a subcutaneous injection to HIV-1 infected participants who were receiving HAART with HIV-1 viral load <50 copies/ml and CD4 cell count >500 cells/mm(3). HIV-1 specific immune responses were monitored by INF-γ enzyme linked immunospot (Elispot) and intracellular cytokine staining (ICS) assay after vaccination. Following the randomized placebo-controlled vaccination phase, subjects who received HIVAX vaccine and who met eligibility underwent a 12-week analytical antiretroviral treatment interruption (ATI). Viral load was monitored throughout the study.

Results: HIVAX was well tolerated in trial participants. Transient grade 1 to 2 (mild to moderate) injection site reactions occurred in 8 of 10 vaccinated participants. HIVAX was immunogenic in all vaccinated participants. The functionality of T cells was significantly enhanced after vaccination. Median viral load (3.45 log10 copies/ml, range of 96-12,830 copies/ml) at the end of the 12-week treatment interruption in HIVAX vaccinated group was significantly lower than the pre-treatment levels. Three vaccinated participants extended ATI for up to 2 years with stable CD4 cells and low viral loads.

Conclusions: HIVAX vaccine is generally safe, elicits strong anti-HIV-1 immune responses, and may play an important role in controlling viral load during treatment interruption in HIV-1 infected participants.

Keywords: Analytical treatment interruption; HIV-1; Immune responses; Therapeutic vaccine; Vaccine; Viral load.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • AIDS Vaccines / immunology
  • AIDS Vaccines / therapeutic use*
  • Adult
  • Antiretroviral Therapy, Highly Active*
  • CD4 Lymphocyte Count
  • CD4-Positive T-Lymphocytes / immunology
  • CD8-Positive T-Lymphocytes / immunology
  • Cytokines / immunology
  • Double-Blind Method
  • Female
  • HIV Infections / drug therapy*
  • HIV Infections / therapy*
  • HIV-1
  • Humans
  • Immunity, Cellular*
  • Interferon-gamma / immunology
  • Male
  • Middle Aged
  • Viral Load


  • AIDS Vaccines
  • Cytokines
  • IFNG protein, human
  • Interferon-gamma

Associated data

  • ClinicalTrials.gov/NCT01428596