Gilead Sciences has begun a major trial to compare the efficacy of Descovy (emtricitabine/tenofovir alafenamide, or TAF) versus Truvada (tenofovir disoproxil fumarate, or TDF/emtricitabine) as pre-exposure prophylaxis (PrEP) against HIV.
In addition to determining how well Descovy protects against HIV compared with Truvada, the trial will compare the drugs’ effects on bone mineral density and kidney function, as well as other safety data.
The U.S. Food and Drug Administration (FDA) approved Descovy in April 2016 to be used in combination with other antiretrovirals (ARVs) to treat HIV. Researchamong HIV-positive people has shown that the drug is less toxic to the bones and kidneys than Truvada. The reason is that Descovy contains an updated version of the drug tenofovir, called TAF, while Truvada contains the older take on that drug, TDF. Both tablets also contain the drug emtricitabine.