Author Interviews, Infections, Vaccine Studies / 15.05.2017
Toward A Real Cure for HIV: Abivax’s ABX464 Reduced HIV Reservoir in Phase 2 Trial
MedicalResearch.com Interview with:
Jean-Marc Steens, M.D.
Chief Medical Officer of Abivax
MedicalResearch.com: What is the background for this study? What are the main findings?
Response: Antiretroviral therapy (ART) has had an enormous impact on the HIV pandemic since its introduction almost 20 years ago. Most patients treated with ART achieve undetectable or near undetectable plasma levels of the virus. This means that although HIV is controlled, it is not completely eliminated. The virus remains in the body, usually contained in dormant cells (known as the HIV reservoir) that are widely distributed, including to the central nervous system, the gut mucosa, the lymph nodes and other sites. If ART is stopped, the virus rebounds. The goal of any curative therapy would be to eliminate the virus or ensure there is sustained remission in the absence of ART, which until now have been unsuccessful.
Abivax’s Phase 2 clinical study with ABX464 demonstrated, for the first time, a reduction in HIV reservoirs in chronically infected HIV patients as measured by total HIV DNA detected in peripheral blood mononuclear cells (PBMCs).
In the ABX464-004 trial, 30 HIV patients received either ABX464 or matching placebo in addition to their current antiretroviral treatment over 28 days. The viral load at the start of the study was well controlled with boosted darunavir. After the 28-day treatment period, all treatments were interrupted until viral load rebound. Baseline and day 28 blood samples were taken to assess the potential effect of ABX464 on the HIV reservoir in PBMCs.
Safety was the primary endpoint in the trial. ABX464 was well tolerated, with no severe adverse events in the treatment group. Amongst evaluable patients (4 placebo and 14 ABX464-treated patients), a reduction in viral DNA copies/mPBMCs was observed in 7/14 treated patients (mean change of -40%, ranging from -27% to -67%) and no responders were observed in the placebo group. Responders were defined as patients who had a decrease greater than 25% in total HIV DNA in PBMCs and a reduction of at least 50 copies.
Total HIV DNA in PBMC has been validated as a widely accepted biomarker for measuring the HIV reservoir. Specifically, in untreated patients, total HIV DNA load influences the course of the infection and is therefore clinically relevant. In addition, a correlation exists between the pool of HIV-1 DNA and the replication-competent reservoir.
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