Abstract

Aim
We aimed to investigate the relationship between tocilizumab, one of the biological agents widely used in the treatment of rheumatic diseases, and hepatitis B virus reactivation (HBVr).
Materials and Methods
We retrospectively reviewed the electronic records of all patients who received tocilizumab in our rheumatology outpatient clinic between July 2018 and August 2024. Demographic data, baseline and follow‑up HBV serological markers, liver biochemistry, and details of antiviral prophylaxis were extracted and analysed
Results
A total of 54 patients were included (76.2 % female; mean age 57.5 ± 14.3 years). While HBsAg, anti-HBc Ig G and anti-HBs were requested for all patients before treatment, HBsAg was found to be positive in 1 of 54 patients (1.9%) and anti-HBc Ig G was found to be positive in 26 (48.1%). While antiviral treatment was initiated in 10 (18.5%) of the patients, 9 of those who received treatment were HBsAg negative, anti-HBc Ig G positive, and 1 was HBsAg positive. No patient experienced HBV reactivation during treatment; however, one HBsAg positive patient achieved HBsAg seroclearance. The mean follow-up period was 50.5 ± 22.9 months.
Conclusion
No patient experienced HBV reactivation during tocilizumab therapy, and the single HBsAg‑positive participant on prophylactic tenofovir achieved HBsAg seroclearance. These real‑world data suggest that HBsAg‑negative/anti‑HBc‑positive individuals may be managed with vigilant biochemical and serological monitoring rather than routine antiviral prophylaxis during tocilizumab treatment. Nevertheless, the retrospective single‑centre design and modest sample size limit the strength and generalisability of these findings; larger prospective studies are required for definitive guidance.

Key words: Rheumatological disease, tocilizumab, hepatitis B virus reactivation