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  ID Week
Oct 21 - October 25
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Impact of Age and Medical Comorbidities on Renal Outcomes in the DISCOVER Trial
  IIDWeek Oct 21-25 virtual
Reported by Jules Levin


Background: In DISCOVER, emtricitabine/tenofovir alafenamide (F/TAF) was noninferior to F/tenofovir disoproxil fumarate (TDF) for preexposure prophylaxis (PrEP) in men who have sex with men and transgender women, with a superior renal laboratory profile. The differential impact of F/TAF and F/TDF on renal parameters among older individuals and those with medical comorbidities is unknown.
Methods: DISCOVER randomized participants 1:1 to daily blinded F/TAF or F/TDF. We examined renal outcomes at week 48 including estimated glomerular filtration rate (eGFR) by Cockcroft-Gault, β2 microglobulin (M):Creatinine (Cr) and retinol binding protein (RBP):Cr ratios (markers of proximal renal tubular function), and discontinuations due to investigator reported study drug-related renal adverse events (AEs).
Results: Median age was 34 years (yrs)(range 18-76), with 12.5% vs 10.9% < 25yrs, 12.2% vs 14.4% ≥ 50yrs, and 1.1% vs 0.9% > 65yrs for F/TAF and F/TDF, respectively. The prevalence of medical comorbidities at baseline were; eGFR < 90mL/min= 9.1% vs 9.3%, diabetes= 2.9% vs 3.3%, and hypertension= 10.5 vs 11.1%, for F/TAF and F/TDF, respectively. eGFR changes by age category and medical comorbidity status are found in the Table. Forty participants had study drug-related renal AEs; 14 with F/TAF and 26 with F/TDF. Of these, 25% were > 50yrs, 20% had baseline eGFR < 90mL/min, 7.5% had history of diabetes, and 22.5% had history of hypertension. β2M:Cr and RBP:Cr changes were more favorable in participants receiving F/TAF, with greater magnitude of difference in older participants (data not shown).Table.
Conclusion: The DISCOVER trial allows for a large single variable comparison of the two tenofovir prodrugs in the absence of underlying HIV infection and in the absence of third antiretroviral agents. F/TAF was associated with favorable changes in renal biomarkers regardless of age or medical comorbidity. Participants ≥50yrs or with comorbidities were proportionately more likely to develop study drug related renal AEs, but these were present in the minority of cases.