Tenofovir alafenamide: An initial experience at Groote Schuur Hospital, Cape Town, South Africa

Hepatitis B virus (HBV) remains endemic in South Africa (SA), with a concomitantly high prevalence of HIV co-infection. Chronic kidney disease in these subpopulations also has a high prevalence. Tenofovir is an important component of management, but the associated risk of nephrotoxicity makes dosing a challenge in patients with impaired kidney function. A new formulation, tenofovir alafenamide fumarate (TAF), with a more favourable renal toxicity profile, is now available.

To evaluate our initial experience of TAF use at Groote Schuur Hospital, Cape Town.

We retrospectively reviewed patients with HBV mono-infection and HIV-HBV co-infection who were initiated on TAF since 2018. We recorded all relevant demographic, serological, virological and biochemical data from patient records. Adherence was documented by pill collection at the pharmacy.

A total of 26 patients were included in the evaluation, median (interquartile range (IQR)) age 48 (39 - 51) years, 73% (n=19) male, 27% (n=7) hepatitis B e-antigen-positive, and 46% (n=12) HIV co-infected. The median (IQR) duration of treatment with TAF was 13 (9 - 15) months. The median (IQR) baseline creatinine level was 180 (130 - 227) µmol/L, with significant improvement at 12 months, 122 (94 - 143) µmol/L; p=0.017. Reflecting this change, the estimated glomerular filtration rate improved significantly from baseline to month 12 (42 (25 - 52) and 51 (48 - 68) mL/min/1.73 m2, respectively; p=0.023). Similarly, serum alanine aminotransferase (ALT) normalised from a baseline of 33 (18 - 52) to 18 (15 - 24) U/L at month 12 (p=0.012). HBV DNA viral load also declined, from a baseline of log10 4.04 (2.5 - 7.8) IU/mL to a median of <log10 1.3 IU/mL at month 12. HIV viral load was less than the lower level of quantification at months 6 and 12.

TAF was well tolerated, with stable and significantly improving kidney function throughout a 12-month follow-up period. Serum ALT normalised, mirrored by declining HBV viral load. HIV viral load remained undetectable at 6 and 12 months.