Antigenic Competition in HIV Preventive Vaccines
|HIV Infections||Biological: rAd5 Gag-Pol Env A/B/C Biological: rAd5 Gag-Pol||Phase 1|
|Study Design:||Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double (Participant, Care Provider)
Primary Purpose: Prevention
|Official Title:||A Randomized, Double Blind Phase 1b Trial to Examine the Influence of Antigenic Competition on the Immunogenicity of HIV-1 Gag/Pol: A Comparison of rAd5 Gag/Pol Env A/B/C to rAd5 Gag/Pol|
- Magnitude of Gag and/or Pol-specific T-cell responses, as measured by Enzyme-Linked Immunospot (ELISpot) [ Time Frame: Measured 4 weeks after immunization ]
- Number of Gag and/or Pol epitopes targeted by CD4+ and CD8+ T-cells, as measured by ELISpot [ Time Frame: Measured 4 weeks after immunization ]
- Number of individuals mounting T-cell responses to Gag and/or Pol, as assessed by ELISpot [ Time Frame: Measured 4 weeks after immunization ]
- Local and systemic reactogenicity signs and symptoms, laboratory measures of safety, adverse events (AEs), and AEs reported on an expedited basis to Division of AIDS (DAIDS) [ Time Frame: Measured over 6 months after immunization ]
- Magnitude of Gag and/or Pol-specific CD4+ and CD8+ T-cell responses, as measured by intracellular cytokine staining (ICS) [ Time Frame: Measured 4 weeks after immunization ]
|Study Start Date:||January 2011|
|Primary Completion Date:||August 2012 (Final data collection date for primary outcome measure)|
Experimental: Recombinant adenovirus serotype 5 (rAd5) Gag/Pol Env A/B/C
Participants will receive one intramuscular injection of rAd5 Gag/Pol Env A/B/C.
Biological: rAd5 Gag-Pol Env A/B/C
1×10^10 particle units (PU) rAd5 Gag-Pol, Env A/B/C (3:1:1:1 mixture) delivered via intramuscular injection
Active Comparator: rAd5 gag/pol
Participants will receive one intramuscular injection of rAd5 gag/pol.
Biological: rAd5 Gag-Pol
5×10^9 PU rAd5 Gag-Pol delivered via intramuscular injection
HIV vaccines are designed to create an immune response to certain parts of the HIV virus called peptides. Researchers believe that eliciting a response to a peptide called Gag is particularly important. Most HIV vaccines in current clinical trials combine multiple peptides, but including these other peptides may cause antigenic competition. Antigenic competition occurs when the body's immune system reaction to one part of a vaccine weakens or inhibits the response to another part of the vaccine. Specifically, this study is concerned that having too many other peptides in a vaccine might weaken the specific immune response to Gag. This study will test whether a vaccine which only includes the peptides Gag and Pol elicits a stronger immune response to Gag and Pol than a vaccine that also includes the peptides Env A, B, and C.
Participation in this study will last 6 months. The number of study visits will vary by study site. Participants will be randomly assigned to receive injections of one of two vaccines in their upper arm. One group of participants will receive rAd5 gag/pol, which contains only the Gag and Pol peptides, while the other group of participants will receive rAd5 gag/pol Env A/B/C, which contains the Gag, Pol, and Env A, B, and C peptides. For 3 days after injection, participants will need to record their temperature and any side effects, and they will be contacted by study staff 7 days after the injection for follow-up monitoring.
During study visits, participants will complete the following assessments: an HIV test; a physical exam; collection of blood samples; a pregnancy test; and an interview about health, medications, HIV risk behaviors, and experiences with the study.
Participants will be contacted by study staff once a year for 5 years after the vaccination for follow-up health and safety monitoring.
Please refer to this study by its ClinicalTrials.gov identifier: NCT01159990
|United States, Massachusetts|
|Brigham and Women's Hospital Vaccine CRS (BWH VCRS)|
|Boston, Massachusetts, United States, 02115-6110|
|United States, New York|
|Columbia P&S CRS|
|New York, New York, United States, 10032-3732|
|New York Blood Center CRS|
|New York, New York, United States, 10065|
|Sao Paulo HVTU - CRT DST/AIDS CRS|
|Sao Paulo, Brazil, 04121-000|
|Iquitos, Maynas, Peru, 1|
|Lima, Peru, 04|
|Lausanne Vaccine and Immunotherapy Center CRS|
|Lausanne, Vaud, Switzerland, 1011|
|Study Chair:||Esper Kallas, MD, PhD||University of Sao Paulo|