Switching Tenofovir Disoproxil Fumarate (TDF) to Tenofovir Alafenamide Fumarate (TAF) in Hepatitis B/HIV Co-Infection: A Feasibility Study.

PURPOSE: Tenofovir alafenamide (TAF) delivers the active metabolite more efficiently to target cells compared with tenofovir disoproxil fumarate (TDF). Recent studies suggest that TAF is efficacious in treatment naïve individuals who are co-infected with HBV/HIV and may have superior effects on HBV e antigen (HBeAg) seroconversion in this setting. The primary objective of this study was to explore the feasibility of switching from TDF to TAF in HBV/HIV co-infection.

METHODS: In this single-arm, multicenter, open-label study, we recruited patients (n = 20) who were on stable TDF-based antiviral therapy for at least 12 months. All participants had undetectable HIV RNA and HBV DNA levels at the time of screening and were converted to a TAF-based treatment regimen (TAF + emtricitabine + third agent) for 48 weeks.

FINDINGS: Twenty-seven individuals were invited to take part in the screening process; 3 met the exclusion criteria and a further 4 withdrew consent prior to enrolment. The remaining participants were predominantly male (70%), non-cirrhotic (95%) and of Afro-Caribbean ethnicity (60%). All were co-infected with HIV-1 and established on long-term antiretroviral treatment prior to enrolment (median 6.5 years). No adverse events related to the study drug were observed, and most patients (89.5%) maintained undetectable HIV RNA and HBV DNA throughout the follow-up period.

IMPLICATIONS: Switching from TDF to TAF in HBV/HIV co-infection was safe, well tolerated and maintained virological suppression in most patients. Additional studies are needed to confirm these findings in larger cohorts and explore other endpoints.