TAF as a replacement for tenofovir (TDF)

A new formulation of tenofovir, called tenofovir alafenamide (TAF), has been approved for use in combination with other antiretroviral drugs.

TAF is a prodrug of tenofovir disoproxil fumarate (TDF), the agent used in previous formulations. It is converted into active drug in the body and reaches higher concentrations in cells than TDF. As a result, a much smaller quantity of TAF is needed (25mg or 10mg).

TAF is now included in the following approved products:

  • Descovy (TAF/emtricitabine)
  • Genvoya (TAF/emtricitabine/elvitegravir/cobicistat)
  • Odefsey (TAF/rilpivirine)

There was no significant difference in virological or immunological response to TAF when compared to TDF in studies examining the use of either drug in combination with other antiretroviral agents.

Studies have shown consistently that people taking TAF had less kidney toxicity or bone loss than people taking TDF. It is unclear if these reductions in laboratory measurements of kidney function and bone density will translate into long-term reductions in kidney damage or fewer fractures.

Fewer people taking TAF discontinued treatment due to kidney injury than people taking TDF in two phase III studies, although the number of events was small (4 vs 0). The phase III studies of TAF in first-line treatment combined with elvitegravir and cobicistat also found a smaller reduction in bone mineral density in the first year after starting treatment in people taking TAF when compared to TDF.1

People switched from TDF-containing regimens to TAF-containing regimens continued to maintain viral suppression at the same rate as people taking TDF-containing regimens in another 48-week phase III study, and showed modest improvements in kidney function and bone mineral density.2

References

  1. Sax P et al. Tenofovir alafenamide versus tenofovir disoproxil fumarate, coformulated with elvitegravir, cobicistat, and emtricitabine, for initial treatment of HIV-1 infection: two randomised, double-blind, phase 3, non-inferiority trials. The Lancet 385 (9987), pp. 2606-15, 2015
  2. Mills A et al. Switching from tenofovir disoproxil fumarate to tenofovir alafenamide in antiretroviral regimens for virologically suppressed adults with HIV-1 infection: a randomised, active-controlled, multicentre, open-label, phase 3, non-inferiority study. The Lancet Infectious Disease 16 (1), 43-52, 2016
Community Consensus Statement on Access to HIV Treatment and its Use for Prevention

Together, we can make it happen

We can end HIV soon if people have equal access to HIV drugs as treatment and as PrEP, and have free choice over whether to take them.

Launched today, the Community Consensus Statement is a basic set of principles aimed at making sure that happens.

The Community Consensus Statement is a joint initiative of AVAC, EATG, MSMGF, GNP+, HIV i-Base, the International HIV/AIDS Alliance, ITPC and NAM/aidsmap
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