Re-boosting of HIV-1 Infected Subjects With Vacc-4x
Condition: HIV-1 Infection
MeSH terms: Infections
Study type: Interventional
Phase: Phase 2

Summary: 
      During the course of HIV infection the number of CD4 cells decreases, resulting in a reduced
      immunological response and eventually immune deficiency. Vacc-4x is a peptide-based HIV
      immunotherapy vaccine and is anticipated to strengthen the immune system's response to HIV.

      All patients participating in this trial have previously received the vacc-4x vaccine in
      order to reduce the amount of HIV-1 virus in the blood and increase the immune response. The
      primary objective of this study is to evaluate if a re-boost with Vacc-4x could further
      reduce the amount of HIV-1 virus and increase the immune response.
    

Detailed description: 
      Human immunodeficiency virus (HIV) infects the cluster of differentiation 4 (CD4) subset of
      T-cells that are critical for initiating immune responses to infection. The level of CD4
      cells in the blood is a marker of a patient's immunological status. During the course of an
      HIV infection, the number of CD4 cells decreases, resulting in reduced immunological
      responsiveness and ultimately immune deficiency.

      Current management of an HIV infection includes antiretroviral therapy (ART). The advent of
      effective ART in 1996 led to a profound decrease in type 1 HIV (HIV-1)-associated morbidity
      and mortality in developed countries where ART has been available.

      Despite the ability of ART to inhibit HIV-1 replication, it cannot cure infection, making ART
      a lifelong treatment that requires sustained compliance and imposes significant individual
      and societal financial burdens on healthcare services. Furthermore, ART side effects (e.g.,
      metabolic toxicity and stigmatizing body fat redistribution) often require medication that
      further increases the inconveniences and financial burdens of HIV management. Of additional
      concern is the emergence of viruses resistant to ART that can result in treatment failure.

      Vacc-4x is a peptide-based HIV therapeutic vaccine. The primary objective of Vacc-4x
      therapeutic vaccine is to strengthen the immune system's response to HIV p24. ART
      dramatically reduces the level of virus in circulation in the body, thereby allowing the
      immune system to focus on the therapeutic vaccine that is administered. ART also allows for
      the generation of new naïve CD4 cells that can be triggered by the therapeutic vaccine to
      generate new immune responses to HIV-1. Subjects are therefore immunized with Vacc-4x in the
      presence of ART to generate new HIV-specific immune responses that can sustain immunological
      fitness for prolonged periods when patients are removed from ART. It is likely that periodic
      boosting on ART will be required to sustain the immunotherapeutic effect - in this way ART
      may become an intermittent therapy.

      This study is a follow-up, re-boosting study of Study CT-BI Vacc-4x 2007/1 (EudraCT Number
      2007-006302-13) performed in US and Europe (UK, Germany, Spain and Italy). All subjects to be
      included have been given a therapeutic immunization with Vacc-4x during the CT-BI Vacc-4x
      2007/1 study. During the study a reduction in the viral load set-point (mean viral load at
      Week 48 and Week 52, or if Week 52 not reached, mean viral load of the last two measured
      values before restart of ART) was seen in the Vacc-4x group compared to placebo group.
      Further stimulation of the immune system by re-boosting with Vacc-4x could reduce the viral
      load set-point further.
    

Intervention name(s): Vacc-4x
Intervention type(s): Biological
Intervention description(s): Vacc-4x is a peptide-based HIV immunotherapy administered intradermally. Vacc-4x peptides are reconstituted in sterile water.
Other intervention name(s): Combination of Vacc-10, Vacc-11, Vacc-12 and Vacc-13
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: CD4; Clinical trial; Human immunodeficiency virus-1 (HIV-1); HIV; Immunomodulary; Infection; Phase II; Re-boost; Vaccine; Vacc-4x