TAF for HIV-HBV With Renal Dysfunction

The investigators aim at describing changes in renal glomerular and tubular function with after the switch from TDF to TAF in HIV/HBV-coinfected patients with mild to moderate renal dysfunction and to assess the virological efficacy of TAF on HBV infection. The study will include HIV/HBV-coinfected participants of the Swiss HIV Cohort Study (SHCS) who are under active care and have been on a stable, TDF-containing ART regimen for at least 6 months. Only patients with an estimated glomerular filtration rate (GFR) between 30 ml/min and 90 ml/min will be included. All individuals who agree to participate will be switched from a TDF-containing ART regimen to a TAF-containing triple ART regimen at week 0 and will be followed for 48 weeks after the treatment change.

Rationale: Tenofovir alafenamide (TAF) has been shown to cause less renal complications than tenofovir disoproxil fumarate (TDF) while having the same virological efficacy against HIV and HBV infections. In a recent study from the USA and Japan, over 90% of HIV/HBV-coinfected individuals had a suppressed HBV viral load 48 weeks after TDF was replaced by TAF. Thus, TAF might be a valuable treatment option for HIV/HBV-coinfected individuals with TDF-toxicity, especially in the context of resistance to lamivudine and entecavir. However, the safety and efficacy of TAF has not been evaluated to date in HIV/HBV-coinfected patients with renal dysfunction. Primary objectives: * To evaluate changes in glomerular and tubular renal function after switch from TDF to TAF in HIV/HBV coinfected patients with renal dysfunction * To assess the HBV virological efficacy of TAF in HIV/HBV coinfected patients with renal dysfunction switching from TDF to TAF. Secondary objectives: * To assess the percentage of and reasons for treatment interruptions * To describe toxicity events including liver-related complications * To evaluate changes in liver fibrosis Intervention: In eligible patients willing to participate and who have signed an informed consent TDF will be replaced by TAF on day 1 of the study. Products: * Tenofovir alafenamide/emtricitabine (TAF/FTC) Dose: one tbl. once per day in addition to at least one third compound OR * Elvitegravir/cobicistat/emtricitabine/tenofovir alafenamide (EVG/COBI/FTC/TAF) Dose: one tbl. once per day Study Population: eligible patients from all 7 centers of the Swiss HIV Cohort Study will be considered.