NEW ORLEANS, LA—Switching patients 50 years of age or older infected with HIV from emtricitabine/tenofovir disoproxil fumarate (FTC/TDF) to emtricitabine/tenofovir alafenamide (FTC/TAF) improved bone and renal safety compared with those who remained on FTC/TDF, study results reported at IDWeek have shown.

“This is of particular importance as the population living with HIV ages, and experiences more renal and bone-related complications,” stated Eric S. Daar, MD, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA. Previously, TAF has demonstrated an improved renal and bone safety profile when compared with TDF.

The 48-week subgroup analysis examined efficacy (prespecified) and safety (post-hoc) of the two regimens in virologically suppressed HIV-infected participants aged ≥50 years enrolled in a double-blind active-controlled study.

Of the 663 patients treated, 294 were ≥50 years; 150 had switched to FTC/TAF, and 144 had continued on FTC/TDF; all remained on their original third agent.

Baseline viral load, CD4 counts, renal laboratory parameters, and bone mineral density (BMD) were similar between the two arms within those younger and older than 50 years of age.

At Week 48, for those ≥50 years, virologic success using the Food and Drug Administration (FDA) snapshot algorithm was 96.0% for FTC/TAF compared with 94.4% for FTC/TDF. Among those younger than age 50 years, virologic success was 92.9% vs. 91.9%, respectively.

The older group discontinued FTC/TAF at a rate of 3% vs. 1% for FTC/TDF; among younger patients, this rate was 1.1% vs. 0.5%, respectively.

Assessment of renal safety using estimated glomerular filtration rate (eGFR) and renal biomarkers (urine protein:creatinine ratio, urine albumin:creatinine ratio, urine retinol binding protein:creatinine ratio, and urine beta-2-microglobulin: creatinine ratio) and bone safety, using changes in BMD at the spine and hip, showed “significant differences between the two arms that consistently favored FTC/TAF over FTC/TDF” in both age groups, he noted. The P values were all <0.0001, with the exception of P=.006 for urine albumin:creatinine ratio in the older patients and P=0.002 for change in median eGFR in the younger group.

“Efficacy and safety including renal and bone safety parameters were consistent with overall study population and those <50 years,” Dr. Daar concluded.