Durability of Telbivudine-Associated Improvement of Renal Function Following Withdrawal or Switching of Antivirals in Chronic Hepatitis B Patients

Background. Besides antiviral activities against hepatitis B virus (HBV), telbivudine has an extrahepatic pharmaceutical effect: To improve renal function assessed by estimated glomerular filtration rate (eGFR). However, the durability of this effect after withdrawal of telbivudine or switching to other antivirals has never been investigated. Methods. We conducted a postmarketing, real-world observation study for telbivudine treatment. The durability of telbivudine- A ssociated renal function improvement was examined following withdrawal/switching of antivirals. Results. Of 160 telbivudine-treated, chronic hepatitis B patients, 21, 6, and 2 patients were loss to follow-up, dead, and pregnant during the study, respectively. Of the remaining 131 patients, 26, 47, 28, and 30 patients experienced telbivudine withdrawal, continuous use of telbivudine, switching to entecavir, or switching to tenofovir, respectively. During the first 2 years, eGFR in telbivudine-treated patients significantly improved before withdrawal/switching of antivirals (P = .009). Thereafter, eGFR remained unchanged for >1 year in the withdrawal (P = .100) and continuous use (P = .517) subgroups, but decreased significantly in the switching to entecavir (P = .002) and switching to tenofovir (P <.001) subgroups. Multivariate logistic regression analysis revealed that switching to tenofovir and poor liver functional reserve were predictors for eGFR deterioration. Conclusions. Telbivudine-associated renal function improvement was durable after withdrawal or continuous use of telbivudine. However, renal function deteriorated if patients were switched to entecavir or tenofovir.