Long-Term Safety and Efficacy of TAF vs. TDF in Blacks and Non-Blacks

For black adults, is switching therapy to FTC/TAF from FTC/TDF linked to improvements?
For black adults, is switching therapy to FTC/TAF from FTC/TDF linked to improvements?

This article is written live from ID Week 2017 Annual Meeting in San Diego, CA. MPR will be reporting news on the latest findings from leading experts in infectious diseases. Check back for more news from IDWeek 2017.


SAN DIEGO—Among HIV-infected, virologically suppressed black adults, emtricitabine/tenofovir alafenamide (FTC/TAF) showed improvements in renal and bone safety compared to emtricitabine/tenofovir disoproxil fumarate (FTC/TDF), according to Jason A. Flamm, MD, from Kaiser Permanente, Sacramento, CA, and coauthors.

At Week 96, FTC/TAF "demonstrated high rates of virologic suppression, improved bone and renal safety, and small increases in lipids, with no treatment differences in total cholesterol:HDL ratio," reported Dr. Flamm and colleagues. "Efficacy and safety of FTC/TAF in black patients were similar to those in nonblack patients."

"Given the safety advantage of TAF vs. TDF from a renal standpoint, FTC/TAF is an important backbone for black patients living with HIV," the authors concluded.

The research team performed a 96-week subgroup analysis by race for pre-specified efficacy and post-hoc safety outcomes, using data from a randomized, double-blind, active-controlled study (n=663) in virologically suppressed adults with HIV infection who switched to FTC/TAF from FTC/TDF (n=333) vs. continuing FTC/TDF while taking the same third agent (n=330). 

Twenty percent of patients identified themselves as black. Baseline viral load, CD4 cell counts, renal laboratory parameters, and bone mineral density (BMD) were similar between the 2 treatment arms for blacks and non-blacks. 

At Week 96, virologic success among black patients was 87% for FTC/TAF vs. 88% for FTC/TDF and 89% vs. 90% for non-blacks. 

Adverse events leading to study drug discontinuation occurred in 1 (2%) black patient in the FTC/TDF group and 4% of non-black patients (8 patients [3%] in the FTC/TAF group and 3 [1%] in the FTC/TDF group). Adverse events leading to discontinuation included (1 patient each): insomnia/mood alteration, dysphagia, atrial fibrillation, diarrhea, peripheral edema, overdose, lymphoma, increased serum creatinine, rectal tenesmus, feeling abnormal/headache, renal tubular disorder, and acquired lipodystrophy/affective disorder.

The renal tubular disorder case involved a non-black patient in the FTC/TDF group.

Renal biomarkers at Week 96 demonstrated a difference in the median change in eGFR of 10.1 for FTC/TAF group-patients vs. 4.0mL/min in the TDF/TAF group (P=0.06) among black patients. That difference in median change in eGFR was similar to the 10.0 vs. 3.9mL/min changes reported for non-blacks. 

Among black patients, median percent-change in urine protein:Cr and urine β2M:Cr were significantly different between those in the FTC/TAF group and the FTC/TDF group (-21.5% vs. 6.3% and -16.6% vs. 26.8%, respectively; P=0.01 and P<0.001).

In general, FTC/TAF showed improvements in renal and bone safety vs. FTC/TDF along with sustained efficacy at Week 96. "These results support switching to FTC/TAF from FTC/TDF for the treatment of HIV-1 infection in Black adults," concluded Dr. Flamm.

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Reference:

Flamm, JA. Efficacy and Safety of Tenofovir Alafenamide vs Tenofovir Disoproxil Fumarate in HIV-infected, Virologically Suppressed Black and Non-Blacks Adults Through Week 96: Subgroup Analysis of a Randomized Switch Study. Poster presented at IDWeek; October 4–8, 2017; San Diego, CA. http://www.idweek.org