ABX464 Decreases the Total Human Immunodeficiency Virus (HIV) Reservoir and HIV Transcription Initiation in CD4+ T Cells From Antiretroviral Therapy–Suppressed Individuals Living With HIV

Background Antiretroviral therapy (ART) intensification and disruption of latency have been suggested as strategies to eradicate HIV. ABX464 is a novel antiviral that inhibits HIV RNA biogenesis. We investigated its effect on HIV transcription and total and intact HIV DNA in CD4+ T cells from ART-suppressed participants enrolled in the ABIVAX-005 clinical trial (NCT02990325). Methods Peripheral CD4+ T cells were available for analysis from 9 ART-suppressed participants who were treated daily with 150 mg of ABX464 for 4 weeks. Total and intact HIV DNA and initiated, 5’elongated, unspliced, polyadenylated, and multiply-spliced HIV transcripts were quantified at weeks 0, 4, and 8 using ddPCR. Results We observed a significant decrease in total HIV DNA (P = .008, median fold change (mfc) = 0.8) and a lower median level of intact HIV DNA (P = not significant [n.s.], mfc = 0.8) after ABX464 treatment. Moreover, we observed a decrease in initiated HIV RNA per million CD4+ T cells and per provirus (P = .05, mfc = 0.7; P = .004, mfc = 0.5, respectively), a trend toward a decrease in the 5’elongated HIV RNA per provirus (P = .07, mfc = 0.5), and a lower median level of unspliced HIV RNA (P = n.s., mfc = 0.6), but no decrease in polyadenylated or multiply-spliced HIV RNA. Conclusions In this substudy, ABX464 had a dual effect of decreasing total HIV DNA (and possibly intact proviruses) and HIV transcription per provirus. To further characterize its specific mechanism of action, long-term administration of ABX464 should be studied in a larger cohort. Clinical Trials Registration NCT02990325.