Occult Hepatitis B Virus Infection and HBV Reactivation After Switching to Long Acting Therapy in Patients With HIV-1

Observational prospective, multicenter, single-arm study with additional procedure in people living with HIV-1 and having serological markers of previous HBV infection: anti-core antibodies and/or antibodies against surface antigen (HBsAb) and switching from nucleoside analogue therapy to long-acting therapy including cabotegravir (CAB, HIV-1 integrase inhibitor) + rilpivirine (RPV, non-nucleoside HIV-1 reverse transcriptase inhibitor) intramuscularly 1 time every 2 months. Primary Objective To study the risk of HBV reactivation from the phase of possible virological reactivation (HBV-DNA \>=10 IU/mL), when the liver enzymes are within normal limits to overt HBV infection. Overt HBV infection is characterized by positive HBV-DNA, possible positivity of surface antigen (HBsAg) with or without altered liver enzymes in HIV-1 patients with OBI, with switch from ART, which includes nucleos(t)ide analogues active on the two HIV/HBV viruses, to the long-term formulation in which nucleos(t)ide analogues active on the two viruses are not included. Secondary Objectives * To evaluate the effect, in the context of HBV reactivation, of HBV-RNA as a surrogate marker of the transcriptional activity of the covalently closed circular (cccDNA) which is present as an HBV replication intermediate at the hepatocyte level. * Examine the mutational profile of HBV domains (pre-S1 and S genes, X gene), mutations in the nucleocapsid promoter region and the pre-core/core variant, capable of influencing HBV replication efficiency, including also the analysis of mutants characterized as viral escape. Exploratory Objectives To study the mutational profile of the regions of the hepatitis B virus (HBV) able to influence replication efficiency. The study will include subjects living with HIV, followed at the San Luigi Center (Infectious Diseases), IRCCS Ospedale San Raffaele in Milan, Integrated Infectious Risk Management Department, Policlinico S. Orsola-Malpighi in Bologna, and the Department of Mental and Physical Health and Medicine prevention, University of Campania L. Vanvitelli of Naples, who agree to the switch from the current antiretroviral regimen which includes drugs active on HIV/HBV to long acting therapy.