Nephrotoxicity was similar with tenofovir or entecavir.

Both tenofovir and entecavir are considered first-line oral antiviral agents for chronic hepatitis B virus (HBV) infection. In previous studies, nephrotoxicity has been observed with tenofovir therapy in patients coinfected with HBV and HIV. However, whether similar renal toxicity is present during tenofovir therapy in patients with HBV monoinfection is unclear.

This community-based, retrospective study compared nephrotoxicity in 80 patients with HBV infection who were treated with tenofovir (300 mg with varying frequency) — alone or in combination with another antiviral — and in 80 age- and sex-matched patients treated with entecavir alone (0.5 mg or 1 mg with varying frequency). Nephrotoxicity was defined as an incidence of serum creatinine (SCr) 2.5 mg/dL, an increase in SCr of 0.2 mg/dL, a drop in the estimated glomerular filtration rate (eGFR) to <60 mL/min, or an adjustment in medication dosage. The tenofovir and entecavir groups were similar in proportions of patients with diabetes mellitus (20% in each group), history of kidney or liver transplant (20% and 16%), and preexisting renal insufficiency (19% and 13%).

During treatment (mean duration, 80 weeks with tenofovir and 111 weeks with entecavir), more patients in the tenofovir versus the entecavir group had an eGFR <60 mL/min (15 vs. 6; P=0.022) and required medication dose adjustment (13 vs. 4; P=0.021). However, more patients in the entecavir versus the tenofovir group developed a SCr 2.5 mg/dL (6 vs. 1; P=0.053). Of note, in multivariate analysis, therapy assignment was not associated with an increase in SCr of 0.2 mg/dL or in eGFR <60 mL/min. Only history of organ transplant and preexisting renal insufficiency were associated with an increase in SCr of 0.2 mg/dL.

CITATION(S):

Gish RG et al. Similar risk of renal events among patients treated with tenofovir or entecavir for chronic hepatitis B. Clin Gastroenterol Hepatol 2012 Aug; 10:941.