Impact of HBV serological status on HIV virological efficacy of two-drug antiretroviral regimens: A retrospective observational study on virologically suppressed people with HIV switching to lamivudine/dolutegravir.

Objectives: This study aimed to evaluate the HIV virological efficacy of two-drug regimens (2DR) with lamivudine (3TC) and dolutegravir (DTG) in people with HIV (PWH), classified by their hepatitis B virus (HBV) serological status. Specifically, it explored whether isolated anti-hepatitis B core (anti-HBc) positivity impacts virological outcomes.

Methods: A retrospective observational study was conducted at Fondazione Policlinico Universitario Agostino Gemelli IRCCS, enrolling 606 virologically suppressed (HIV-RNA < 50 copies/mL) PWH who switched to a 2DR regimen with 3TC/DTG. Participants were categorized into four groups based on their HBV serological status: hepatitis B surface antibody (HBsAb)-positive/hepatitis B core antibody (HBcAb)-positive, HBsAb-negative/HBcAb-negative, HBsAb-positive/HBcAb-negative, and isolated HBcAb positivity. Viral failure (VF) was defined as two consecutive HIV viral loads above 50 copies/mL or a single HIV viral load above 1000 copies/mL, and viral blips (VBs) as a single HIV-RNA measurement between 50 and 200 copies/mL followed by suppression.

Results: During 2216.4 patient-years of follow-up (PYFU), we observed 30 VFs (1.3 per 100 PYFU) and 63 VBs (2.9 per 100 PYFU). No statistically significant differences in VF or VB were noted between the serological groups. Additionally, no significant alanine aminotransferase (ALT) flares or HBV-DNA breakthroughs were observed, with HBV-DNA remaining undetectable throughout.

Conclusions: The study supports the virological efficacy of 3TC/DTG-based 2DR in PWH, regardless of HBV serological status. Isolated anti-HBc positivity did not influence virological outcomes independently. Larger studies are warranted to further investigate HIV-HBV interactions in this context.