Renal proximal tubulopathy in an HIV-infected patient treated with tenofovir alafenamide and gentamicin: a case report

Safety of Tenofovir Alafenamide in People With HIV Who Experienced Proximal Renal Tubulopathy on Tenofovir Disoproxil Fumarate

BACKGROUND

Proximal renal tubulopathy (PRT) is an infrequent complication of tenofovir disoproxil fumarate (TDF). It remains to be established whether tenofovir alafenamide (TAF) can be safely administered to individuals who experienced PRT on TDF.

METHODS

Individuals with a history of TDF-associated PRT and current estimated glomerular filtration rate (eGFR) over 30 mL/min/1.73 m2 initiated TAF and were followed for 96 weeks. The primary outcome of interest was recurrent PRT. Secondary outcomes were changes in kidney biomarkers, bone biomarkers, and bone mineral density (BMD). Data were analyzed using multilevel mixed-effects linear regression models. The trial was registered under EudraCT 2016-003345-29.

RESULTS

All 31 participants [median age 55 (inter-quartile range 51, 60) years, 97% men, 87% White ethnicity] remained on TAF at week 96, and none developed glycosuria or recurrent PRT. Participants experienced small declines in eGFR-creatinine [-1.9 (95% confidence interval: -3.5 to -0.3) mL/min/1.73 m2/yr; P = 0.024], but not in eGFR-cystatin C [-0.9 (-2.1 to 0.4) mL/min/1.73 m2/yr; P = 0.16]. Ten (32%) and 5 (16%) participants experienced rapid (>5 mL/min/1.73 m2/yr) decline in eGFR-creatinine and eGFR-cystatin C. No significant change in other kidney biomarkers, bone turnover, or BMD was observed (P > 0.2).

CONCLUSIONS

In individuals with a history of PRT on TDF, 96 weeks of TAF was not associated with recurrent PRT or adverse effects on renal tubular function, bone turnover, or BMD. These data suggest that TAF is a treatment option for this vulnerable population.

Tenofovir alafenamide nephrotoxicity: a case report and literature review

Background

Tenofovir alafenamide (TAF), a novel prodrug of tenofovir (TFV), has become the preferred drug for the treatment of HIV-1 and chronic hepatitis B infection in clinical practice. Results from clinical trials showed that it had better renal and bone mineral outcomes compared to tenofovir disoproxil fumarate (TDF). However, as we have seen with TDF, side effects from the new medication can be more prevalent and recognized after extensive use in real world situations. Sporadic cases of acute kidney injury in patients using TAF have started to emerge.

Case presentation

We report a case of 49-year-old Thai, HIV treatment-experienced female with hypertension presented with worsening renal function after switching her antiretroviral regimen from TDF, emtricitabine (FTC), and lopinavir/ritonavir (LPV/r) to TAF, FTC and dolutegravir (DTG) for 3 months. Kidney biopsy showed distinctive picture of tenofovir nephrotoxicity with acute tubular injury and mitochondrial injury. The possible causes of acute kidney injury and nephrotoxicity from TAF for this patient were discussed. We have extensively reviewed all published case reports of TAF-associated nephrotoxicity and summarized the essential information in this article.

Conclusion

Although TAF has less nephrotoxicity compared with TDF; renal function should always be monitored after the initiation of both drugs. Future large cohort studies are required to identify the risk factors of TAF-associated nephrotoxicity and to design an effective preventive strategy.