Efficacy and tolerability of tenofovir alafenamide fumarate prophylaxis in HBV-infected individuals receiving chemo/immunosuppressive therapy.

Background and Aim: This study aimed to determine the efficacy and safety of tenofovir alafenamide fumarate (TAF) prophylaxis in hepatitis B virus (HBV)-infected or HBV-experienced individuals with benign and malignant diseases receiving chemo/immunosuppressive or biological modifier therapy. Materials and Methods: This is a multicenter, observational study in which data from 13 centers were reviewed and entered into a standardized electronic case report form. Results: A total of 158 individuals who received TAF prophylaxis were included in the analysis. Before starting the prophylaxis, 51 individuals were hepatitis B surface antigen positive, while 107 were HBV-experienced. Thirty patients had detectable HBV DNA levels. Twelve of them had abnormal serum alanine aminotransferase levels. Forty patients were switched to TAF. Solid tumors (34%) were the most common primary disease types. The median follow-up period was 17.2 months. From baseline to the end of the follow-up period, none of the patients had clinical, biochemical, or serological evidence of HBV reactivation under TAF prophylaxis. The virological response rate was 87%. HBV suppression was well maintained after switching in the 40 patients who were switched to TAF treatment. All patients maintained their chemo/immunosuppressive therapy without interruption. TAF prophylaxis was well tolerated. No drug discontinuation due to adverse effects was observed. No HBV-related morbidity or mortality was observed during the TAF prophylaxis. No significant differences were found in the glomerular filtration rate change or hypophosphatemia during TAF prophylaxis, but the serum triglyceride levels were significantly increased (p=0.019). Conclusion: TAF prophylaxis is effective, safe, and tolerable in preventing chemo/immunosuppressive or biological modifier-induced HBV reactivation in HBV-infected or HBV-experienced individuals.