Introduction: Current guidelines recommend starting antiviral prophylaxis to prevent hepatitis B virus (HBV) reactivation in patients receiving immunosuppressive treatments (IST). The aim of this study was to compare the efficacy of entecavir (ETV) and tenofovir disoproxil fumarate (TDF) for prophylaxis.

Methods: Patients, who were HBsAg and/or anti-HBc IgG positive and scheduled to receive IST for oncologic and hematologic diseases, were enrolled into the study. Those who were already receiving an antiviral treatment for HBV or had an associated HIV, hepatitis C, D were excluded. The remaining patients with a prophylaxis indication according to the AGA guideline were randomized to receive either ETV (0.5 mg/day) or TDF (245 mg/day). Prophylaxis was continued for 6-12 months after completion of IST. Patients were followed up for 1 year after completion of prophylaxis. The HBV reactivation rates and side effects of the drugs were compared.

Results: The study group included 120 patients. There was no significant difference between the demographic data, viral serologic parameters and reactivation risk profiles of the ETV (n = 60) and TDF (n = 60) groups. Forty-one patients in the ETV and 36 in the TDF group completed the antiviral prophylaxis, and no HBV reactivation was observed. HBV reactivation was observed in 4 of 37 patients (10.8%) in the ETV group and 5 of 35 (14.3%) patients in the TDF group (including one with flare) during the follow-up after completion of prophylaxis. Ten patients in the ETV group (16.7%) and 14 patients (23.3%) in the TDF group experienced side effects (p = 0.77). One patient in the TDF group had to switch to ETV due to severe itchy, maculopapular rash-like lesions.

Conclusions: ETV and TDF had a similar efficacy in the prophylaxis of HBV reactivation in patients undergoing IST, with none of the patients experiencing reactivation.