Toward A Real Cure for HIV: Abivax’s ABX464 Reduced HIV Reservoir in Phase 2 Trial Interview with:
AbivaxJean-Marc Steens, M.D.

Chief Medical Officer of Abivax 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.

Jean-Marc Steens, M.D. Chief Medical Officer of Abivax

Dr. Steens What should readers take away from your report?

Response: These results in patients are a first and very important step in supporting the hypothesis that ABX464 could impact the HIV reservoir. Currently approved drugs can effectively reduce and control the replication of HIV in humans, allowing many patients to live with chronic treatment, but no drugs have been able to eradicate the virus because it evades therapy by hiding in these HIV reservoirs. What recommendations do you have for future research as a result of this study?

Response: In this Phase IIa clinical trial, during which patients were treated only for a short period of 28 days, we did not yet see an impact on the time to rebound after treatment interruption. Therefore, the next step will be to evaluate longer treatment duration with ABX464, which could lead to a profound reduction of the HIV reservoir and potentially become part of a functional cure for HIV patients. Is there anything else you would like to add?

Response: A separate Phase IIa clinical trial (ABX464-005) has already started to study the effects of ABX464 on HIV reservoirs in gut tissues, an area associated with high concentration of HIV reservoir cells. In this previously announced study, patients are receiving ABX464 for 28 days in addition to their antiretroviral treatment. Rectal biopsies are being collected at certain intervals, allowing quantification of the viral load and level of inflammation in the reservoir over time. Based on the recently announced results, ABIVAX plans to amend the ABX464-005 protocol to extend the treatment period to observe the longer-term effects of ABX464 on HIV reservoir suppression. Initial results of the ABX464-005 study are expected in Q3 2017. Thank you for your contribution to the community.

Press Release :A Phase 2 trial of ABX464 impacting HIV blood reservoir, supporting ABX464’s potential to become a key functional cure element for HIV

Note: Content is Not intended as medical advice. Please consult your health care provider regarding your specific medical condition and questions.

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Last Updated on May 15, 2017 by Marie Benz MD FAAD