Inflammatory Markers after Switching to a Dual Drug Regimen in HIV-Infected Subjects: A Two-Year Follow-Up.

Objective: Immunadapt is a study evaluating the impact of combination antiretroviral treatment (cART) simplification on immune activation. We previously showed that switching to dual therapies could be associated six months later with macrophage activation. Followup continued up to 24 months after treatment simplification. Materials and Methods: Immunadapt is a prospective single arm study of successfully treated subjects simplifying cART from triple to dual regimens. Before cART change, at 6 months, and between 18 and 24 months following the switch, we measured IP-10, MCP-1, soluble CD14 (sCD14), soluble CD163 (sCD163), and lipopolysaccharide binding protein. Patients were stratified according to lower or greater likelihood of immune activation (CD4 nadir < 200, previous AIDS-defining event or very-low-level viremia during follow-up). Variables were compared using matched Wilcoxon tests. Results: From April 2019 to September 2021, 14 subjects were included (mean age 60 years, 12 men, 26 years since HIV infection, CD4 nadir 302 cells/mm3, 18 years on cART, 53 months on last cART). Twenty-one months following the switch, all but one subject maintained their viral load < 50 cp/mL. One subject had two viral blips. For the entire population, the sCD163 values increased significantly from baseline (+36%, p = 0.003) and from 6 months after the switch. The other markers did not change. After 6 months, the sCD163 increase was more pronounced in subjects with greater likelihood of immune activation (+53% vs. +19%, p = 0.026) Conclusions: cART simplification to dual therapy was associated with macrophage activation despite successful virological control after almost two years’ follow-up. This was more pronounced in those at risk of immune activation.