Tenofovir Alafenamide: The Future of Pre-Exposure Prophylaxis?

Kenneth Mayer, MD, Medical Research Director, Professor of Medicine, Fenway Health, Harvard University, explains why tenofovir alafenamide may be the future of pre-exposure prophylaxis.

Interview Transcript (slightly modified for readability)

“The specific form of tenofovir that was used in the first-generation [pre-exposure prophylaxis] PrEP studies is called tenofovir disoproxil fumarate (TDF). The same company that makes that compound has made a different version, called (TAF) tenofovir alafenamide. TAF seems to have less toxicity to bone and kidneys and may become the future of PrEP.

There are studies underway to see if TAF is as good as TDF for PrEP in the future. We may have better regimens that may affect bone less significantly. The finding in young people, because the bone is growing, is one that we have to monitor, but it was not clinically significant; it was significant in the sense that testing that we can do to look at bones, in terms of x-rays, called bone densitometry, showed a statistically significant, but clinically insignificant change.

The question is, if you’re 18 years old, and you’re taking this pill every day, and you have a 1% change after a year, [or a] year-and-a-half, after 10 years will you have a 10% change? That could be significant, so, that’s something we have to monitor. But the hope is that the switch to TAF from TDF may be the future of PrEP, [which means] there may be a version of the same drug that may be less toxic to bones.”