There is no cure for HIV infection. Antiretroviral therapy (ART) is widely available but requires daily, life-long intake. This can cause issues around side-effects, resistance, adherence and stigma. A new therapy, broadly neutralising antibodies, (bNAbs), may work as well as ART and may last longer - one dose can last six months. bNAbs appear to first target HIV viruses, then drive a protective immune response conferring long-term control, called the vaccinal effect. AbVax is a clinical trial to understand this effect and how to enhance it to give the strongest possible long-term protection for people living with HIV (PWH). The investigators are studying whether a combination of vaccines that attack HIV, a short period of treatment interruption induced viraemia (TIIV - stopping ART for a few weeks to allow a small amount of virus to return to the bloodstream) and bNABs will produce the most sustained immune protection.
AbVax will recruit 48 otherwise healthy PWH aged 18-64. Participants will be randomised across three groups (arms) to determine the best combination of treatment. In Arm A, participants will undergo a period of TIIV, then receive two bNAb infusions. In Arm B, participants receive a combination of three HIV vaccines (one prime dose followed by two booster doses after 4 and 16 weeks), then are given two bNAb infusions. In Arm C, participants will undergo a period of TIIV, then receive the same vaccination combinations as Arm B, then receive two bNAb infusions. All participants then stop ART for an analytical treatment interruption (ATI) to determine the clinical impact and measure how long before any HIV returns to the blood. This allows the investigators to see if vaccines and TIIV add to the protection provided by bNAbs and by how much.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
48
solution for injection one dose of 2.5 x 10\^10 vp/ml Arm B and Arm C
solution for injection one dose of 2.5 x 10\^10 vp/ml Arm B and Arm C
suspension for injection two doses of 1 x 10\^8 vpu/ml Arm B and Arm C
Solution for infusion 2550 mg Arm A, Arm B and Arm C
Solution for infusion 850 mg Arm A, Arm B and Arm C
Participants pause ART before receiving vaccines and/or bNAbs Arm A and Arm C
Guys and St Thomas' NHS Trust
London, United Kingdom
RECRUITINGSt Mary's Clinical Trial Unit
London, United Kingdom
RECRUITINGCentre for Clinical Vaccinology and Tropical Medicine (CCVTM)
Oxford, United Kingdom
RECRUITINGFold change in T cell immune response to the HIV Gag protein
The geometric mean of the fold-change (GMFC) will be compared between Arm C compared to Arm A; and Arm C compared to Arm B.
Time frame: Baseline and 12 weeks after ATI
Safety Assessment
Occurrence of Serious Adverse Events for the whole study duration.
Time frame: From enrollment until 16 weeks after restarting ART after ATI
Safety Assessment
Number of participants with adverse events (not including SAEs)
Time frame: From enrollment until 16 weeks after ART restart after ATI
HIV viral control
% of participants with undetectable plasma viral load
Time frame: Weeks 12 and weeks 24 after ATI
Immunological correlation of virological remission
CD4 T cell counts and CD8:CD4 ratios
Time frame: Week 12 and week 24 after ATI
Immunological correlates of virological remission
HIV specific T cell immune response using multiple assays
Time frame: Weeks 12 and 24 after ATI
BNAb plasma concentration
bNAb maximum plasma concentration (Cmax)
Time frame: Weeks 12 and 24 after ATI
ART plasma concentration
Maximum plasma concentration (Cmax) of ART
Time frame: Week 12 and week 24 after ATI
Vaccine specific response
Proportion of participants that develop T cell response to HIVconsv immunogens
Time frame: Weeks 12 and 24 after ATI
HIV reservoir assessment
Measures of HIV reservoirs
Time frame: Weeks 12 and 24 after ATI
bNAb escape
Proportion of participants with bNAb resistance
Time frame: Weeks 12 and 24 after ATI
T cell escape
Proportion of participants with T cell escape mutations
Time frame: Weeks 12 and 24 after ATI
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