Bone Density Improves In People Who Switch From Tenofovir DF To Tenofovir Alafenamide

People with low bone density who changed from the older tenofovir disoproxil fumarate (TDF) to tenofovir alafenamide (TAF) saw improved bone health, including a reduction in osteoporosis, the study presented at the Conference on Retroviruses and Opportunistic Infections (CROI 2017) showed. According to the previous study, after three years, TAF for first-line HIV medication was better at suppressing viral load and safer for the bones and kidneys than TDF.

TDF (Viread, also in the Truvada, Atripla, Eviplera and Stribild coformulations) has been one of the most broadly used antiretroviral drugs. It is commonly recognised safe and well-tolerated, but it can cause kidney toxicity in sensitive people and bone loss shortly after starting treatment.

TAF (part of the Descovy, Genvoya and Odefsey co-formulations) is a pro-drug that delivers its active agent more efficiently to HIV-infected cells. TAF produces sufficient intracellular levels with much lower doses, which intends lower concentrations in the blood plasma and less drug exposure for the bones, kidneys, and other organs and tissues.

During the study, the investigators noticed 12 kidney-related events leading to discontinuation – including four cases of renal tubulopathy – in the participants receiving TDF but none in their counterparts receiving TAF. Likewise, six people receiving TDF but none in the receiving TAF discontinued early due to bone-related events. Changes in renal biomarkers were significantly smaller, and there were significantly less hip and spine bone loss in the participants receiving TAF. Fasting lipids raised more among people on TAF, however.

"These longer-term data support the use of elvitegravir/cobicistat/emtricitabine/TAF as a safe, well tolerated and durable regimen for initial and on-going HIV-1 treatment," the researchers concluded.