Comparison of viral control between two tenofovir dose reduction regimens (300 mg every 48 hours versus 300 mg every 72 hours) in chronic hepatitis B patients with moderate renal impairment from tenofovir-induced renal dysfunction.

Long-term use of tenofovir disoproxil fumarate (TDF) can induce renal dysfunction that requires TDF dose reduction. Previous studies showed that systemic drug use exerts a threefold higher risk of moderate renal impairment. This study aimed to compare viral control between two tenofovir dose reduction regimens in chronic hepatitis B (CHB) patients with moderate renal impairment from TDF-induced renal dysfunction. This noninferiority, randomized controlled study was conducted at the Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand. Virologically suppressed CHB patients treated with TDF who had moderate renal impairment were randomly allocated to receive TDF 300 mg either every 48 or 72 hours. Forty-six patients (67.4% male) with a mean age of 62.8 ± 7.8 years were enrolled. Among all patients, 34.8% were HBeAg-positive, and 23.9% had cirrhosis. All included patients completed 12 months of follow-up. No patients had virological breakthrough. After dose reduction, estimated glomerular filtration rate (eGFR) was improved in both groups, but a higher proportion of patients had an eGFR > 60 mL/min/1.73 m2 in the TDF every 72 hours group. Other renal parameters, including serum phosphate, tubular maximal reabsorption for phosphate per GFR, urine protein-to-creatinine ratio, urine sugar and urine neutrophil gelatinase-associated lipocalin, were not significantly different between groups. Among TDF-treated CHB patients with TDF-induced moderate renal impairment, more aggressive dose reduction in TDF from every 48 hours to every 72 hours did not affect virological breakthrough. A higher proportion of patients in the TDF every 72 hours group had improvement in renal function.