Acute interstitial nephritis following treatment with direct-acting antiviral agents in hepatitis C virus-infected patients: A case series.

Hepatitis C virus (HCV) infection has been associated with several extrahepatic adverse clinical outcomes, including an accelerated rate of loss of kidney function in patients with chronic kidney disease (CKD) and an increased mortality in patients with CKD and kidney failure on hemodialysis. Clinical trials using direct-acting antiviral (DAA) agents have uniformly achieved sustained viral response at 12 weeks (SVR) rates of > 90% in the general population as well as in patients with CKD/kidney failure on hemodialysis. Sofosbuvir is a DAA prodrug that is phosphorylated into the active metabolite GS-461203, with subsequent dephosphorylation into the inactive metabolite GS-331007. The kidneys clear both sofosbuvir and GS-331007, and its use has been associated with worsening kidney function in some studies. In the HCV-TARGET study, patients with an estimated glomerular filtration rate (eGFR) < 30 mL/min at the initiation of sofosbuvir-based therapy had higher rates of deterioration of kidney function compared to patients with higher eGFR [1]. However, based on recent data demonstrating safety in patients with advanced CKD, the US Food and Drug Administration (FDA) approved the use of sofosbuvir-containing regimens in patients with CKD 4/5 (eGFR of less than 30 mL/min/1.73m) and end-stage renal disease (ESRD) in late 2019. The current report describes 8 HCV-infected patients who developed acute kidney injury (AKI) with biopsy-proven acute interstitial nephritis (AIN) temporally associated with the use of DAAs. The mean age of the group was 61.3 (± 6 years). The most common HCV genotype (GT) was 1a (n = 7). The DAA formulations were sofosbuvir/ledipasvir (n = 5), elbasvir/grazoprevir (n = 2), and sofosbuvir/simeprevir (n = 1). All patients achieved an SVR. The mean serum creatinine at the initiation of DAA treatment was 1.5 mg/dL (± 0.6) and increased to 2.03 mg/dL (± 0.7) by the last day of DAA administration. The kidney biopsies were performed at a mean of 320 days (± 247) after achieving an SVR, at which point the mean creatinine had increased to 2.3 mg/dL (± 1.4). All patients received a course of high-dose corticosteroids after the diagnosis of AIN was confirmed by biopsy. Serum creatinine levels at 3 and 6 months following the completion of steroid therapy were 2.8 (± 1.2) and 3.1 mg/dL (± 1.5), respectively. Three patients had worsening CKD and progressed to kidney failure requiring hemodialysis. These results are consistent with earlier studies demonstrating the efficacy of the DAAs in HCV-infected CKD patients. Of note, the demonstration of AIN in these patients may explain some of the AKI events reported with the use of DAAs in patients with CKD.