Role of HBcAb Positivity in Increase of HIV-RNA Detectability after Switching to a Two-Drug Regimen Lamivudine-Based (2DR-3TC-Based) Treatment: Months 48 Results of a Multicenter Italian Cohort

: The aim of this study was to evaluate whether the presence of anti-hepatitis B (HBV) c antibodies (HBcAb positivity) could influence the control of HIV viremia in patients living with HIV (PLWH) who switch to two-drug antiretroviral therapy (2DR) containing lamivudine (3TC) (2DR-3TC-based). A retrospective multicentre observational study was conducted on 160 PLWH switching to the 2DR-3TC-based regimen: 51 HBcAb-positive and 109 HBcAb-negative patients. The HBcAb-positive PLWH group demonstrated a significantly lower percentage of subjects with HIV viral suppression with target not detected (TND) at all time points after switching (24th month: 64.7% vs. 87.8%, p < 0.0001; 36th month 62.7% vs. 86.8%, p = 0.011; 48th month 57.2% vs. 86.1%, p = 0.021 of the HBcAb-positive and HBcAb-negative groups, respectively). Logistic regression analysis showed that the presence of HBcAb positivity (OR 7.46 [95% CI 2.35-14.77], p = 0.004) could favour the emergence of HIV viral rebound by nearly 54% during the entire study follow-up after switching to 2DR-3TC.