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Single-Tablet HIV Regimen Containing Tenofovir Alafenamide Improves Bone and Kidney Safety

September 21, 2015

A new coformulation of elvitegravir/cobicistat/emtricitabine/tenofovir (Stribild) containing tenofovir alafenamide (TAF) -- an improved prodrug of tenofovir -- offered better bone and kidney safety, while maintaining viral suppression, in patients who switched from efavirenz/tenofovir/emtricitabine (Atripla), according to a study presented at ICAAC/ICC 2015 in San Diego.

The study, which was presented by David Shamblaw, M.D., followed 376 individuals living with HIV (median age of 39) who had achieved undetectable viral loads while taking efavirenz/tenofovir/emtricitabine. Of these participants, 251 were switched to elvitegravir/cobicistat/emtricitabine/TAF (E/C/F/TAF) and 125 remained on efavirenz/tenofovir/emtricitabine.

After 48 weeks, 96% of the TAF group and 90% of the efavirenz group maintained an undetectable viral load. In terms of bone safety, those in the TAF group had an average change of +1.44% in hip bone mineral density (BMD), compared to -0.24% in the efavirenz group (P < .001). Moreover, the average change in spine BMD was +0.86% for the TAF group and -0.22% for the efavirenz group (P = .048).

In terms of kidney safety, levels of proteinuria and specific proximal tubular proteinuria (indicators of kidney damage) were significantly lower in those in the TAF group than those in the efavirenz group.

Median Percentage Change at Week 48TAF GroupEfavirenz GroupSignificance
Urine Protein: Creatinine-13.8+7.2P < .001
Urine Albumin: Creatinine-16.3+5.4P < .001
Retinol Binding Protein: Creatinine-22.5+24.4P < .001
Beta-2-Microglobulin: Creatinine-42.7+18.9P < .001

The participants were also assessed for central nervous system (CNS) side effects, including dizziness, insomnia, impaired concentration, somnolence and abnormal dreams. At week two, those in the TAF group reported a reduction of 58% while those in the efavirenz group reported a reduction of 5%, according to Shamblaw.

Additionally, a second study examined E/C/F/TAF in patients with an estimated glomerular filtration rate (eGFR) between 30-69 mL/min. Glomerular filtration rate is a measure of how well your kidneys filter out waste products, with a number below 60 signifying kidney damage. The study followed 80 patients who had achieved undetectable viral loads, who were then switched to E/C/F/TAF. After 48 weeks, they maintained a stable eGFR and saw significant reduction in levels of proteinuria. These results suggest that E/C/F/TAF could be a safe option for patients who have impaired kidney function.

The U.S. Food and Drug Administration will decide on the new coformulation of E/C/F/TAF by early November 2015.

Warren Tong is the senior science editor for and

Follow Warren on Twitter: @WarrenAtTheBody.

Copyright © 2015 Remedy Health Media, LLC. All rights reserved.

This article was provided by TheBodyPRO. It is a part of the publication The 55th Interscience Conference on Antimicrobial Agents and Chemotherapy.

Reader Comments:

Comment by: Dawn in DC (Washington D.C.) Thu., Nov. 5, 2015 at 11:40 am UTC
I am a 40 year old female who was diagnosed with HIV in November of 2008.It did not come as a shock to me when I was positive because the lifestyle that I was living at that time was by far a very good one.It took me about 3 years before it really set in that I was positive so during those 3 years I continued to use drugs and I was definitely not taking my medicine on a daily basis.I have been on Isentress and Truvada fromthe beginning of my diagnosis and have not had any type of adverse reactions and my viral load is undetectable but my concern is is it OK to stay on the same medication for so long and I have noticed that myurintion has definatly due erased on how many times I go daily.My maternal grandmother had kidney disease and was on dialysys for approximately 16 years, unfortunately she passed away.Shod I be concerned and should you stay on the she medicationor change over so many years?
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Comment by: Jerome (Antwerpen, Belgium) Thu., Sep. 24, 2015 at 5:02 am UTC
comparing apples to bananas..
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