Long-term efficacy and safety of switching from lamivudine + adefovir to tenofovir disoproxil fumarate in virologically suppressed patients

Background and Aim Tenofovir disoproxil fumarate (TDF) is recommended as first-line monotherapy for nucleos(t)ide (NA)-naïve chronic hepatitis B (CHB) patients and as a second-line rescue therapy for NA-experienced patients with a previous treatment failure. However, data regarding the efficacy of TDF monotherapy in patients with lamivudine resistance (LAM-R) successfully treated with LAM + adefovir (ADV) are limited. Herein, the efficacy and safety of switching from LAM + ADV to TDF monotherapy in clinical practice have been evaluated. Methods Sixty LAM-R HBeAg-negative CHB patients treated with ADV add-on therapy and stable viral suppression, were switched to TDF monotherapy and prospectively evaluated for virological response, liver and renal function, and bone mineral density. Results During a median period of 57 months of TDF monotherapy, all patients maintained a virological response, four of whom cleared HBsAg (6.6%) and discontinued treatment. Monitoring of renal function showed no case of the Fanconi syndrome, no significant alterations of median serum creatinine, eGFR and phosphate levels, although a reduction of TDF dosage was required in five patients (8.3%). Despite the stable virological suppression, five cirrhotic patients and one CHB patient developed hepatocellular carcinoma. Conclusions Our results demonstrate the efficacy of switching to TDF monotherapy in virologically suppressed CHB patients receiving long-term LAM + ADV therapy, with a low rate of adverse events.