Is Tenofovir Alafenamide Safer than Tenofovir Disoproxil Fumarate for the Kidneys?

Tenofovir disoproxil fumarate is currently the cornerstone of HIV treatment. Although it shows an overall good safety profile, numerous cases of nephrotoxicity have been reported. Tenofovir alafenamide is a novel tenofovir prodrug that has been developed to improve renal safety. Pharmacokinetic studies suggest a better renal tolerance of tenofovir alafenamide than tenofovir disoproxil fumarate, probably because tenofovir plasma concentrations are lower after tenofovir alafenamide administration. Consistently in clinical trials, renal tolerance seems to be improved in patients treated with tenofovir alafenamide. However, some questions remain. First, whether tenofovir can accumulate and lead to nephrotoxicity under specific circumstances after tenofovir alafenamide administration is unknown. Second, only "real-world practice" will inform us on the long-term renal safety of tenofovir alafenamide. Last, tenofovir alafenamide renal safety in patients with chronic kidney disease has not been studied in any randomized clinical trial. In conclusion, tenofovir alafenamide appears as a very promising drug and long-term safety will be an important determinant of its expanded use.