Tenofovir alafenamide (TAF) versus tenofovir disoproxil fumarate (TDF)


Eleven randomized trials comparing TAF and TDF for HIV and hepatitis B were analyzed for efficacy, bone toxicity and renal events. A predefined sub-group analysis compared regimens with TAF and TDF with or without boosting with ritonavir (RTV) or cobicistat (COBI). 4,574 patients participated in trials in which both arms received a booster with a total of 7,198 patient years of follow up. 3,537 patients received unboosted regimens for a total of 3,595 years. TDF-treated patients with boosted regimens showed borderline lower HIV-RNA suppression, more bone fractures (p=0.04), larger decreases in bone mineral density (p<0.001) and more discontinuations for bone (p=0.03) and renal (p=0.002) adverse events compared to TAF. Similar differences between TAF and TDF were not found in patients not using a booster. There was no difference in efficacy and only marginal differences in safety between TAF and TDF in the patients receiving unboosted treatments.

Hill et al. Journal of Virus eradication 2018;4:72-79

Comment: Ritonavir and cobicistat modify not only the pharmacokinetics of protease inhibitors but also increase the concentration of TDF. In this meta-analysis, no obvious advantage for TAF compared to TDF was shown with unboosted regimens which may limit the health economic value of TAF in these patients taking the low cost of generic TDF into account.