Risk of hepatitis B reactivation in rheumatologic patients treated with Janus kinase inhibitors

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Kizilkaya B., CÜRE O., Durak S.

ANNALS OF CLINICAL AND ANALYTICAL MEDICINE, vol.17, no.7, pp.738-741, 2026 (ESCI)

Abstract

Aim: Hepatitis B virus (HBV) is a major public health problem that infects people worldwide. Janus kinase (JAK) inhibitors, while effective in the treatment of rheumatologic diseases, carry a potential risk of HBV reactivation. This study aimed to evaluate the risk of HBV reactivation and the effect of antiviral prophylaxis in rheumatologic patients treated with JAK inhibitors. Methods: Fifty patients who were initiated on JAK inhibitors (tofacitinib, upadacitinib, baricitinib) in the rheumatology clinic between January 2020 and February 2025 and followed for at least 6 months were retrospectively evaluated. All patients underwent testing for HBsAg, anti-HBc IgG, and anti-HBs before treatment. HBV reactivation was defined as HBV DNA positivity or seroconversion in an HBsAg-negative patient, or a >= 10-fold increase in HBV DNA in an HBsAg-positive patient. Results: 78% of the patients were female, and the mean age was 54.5 +/- 12.4 years. The most common diagnosis was rheumatoid arthritis (80%). One patient (2%) was HBsAg-positive, and 19 (38%) were anti-HBc IgG-positive. Antiviral prophylaxis was initiated in 12 patients (24%); 9 of these patients were HBsAg-negative/anti-HBc-positive. The agents used were entecavir (n = 6), tenofovir disoproxil (n = 4), and tenofovir alafenamide (n = 2). During a mean follow-up of 29.4 +/- 20.3 months, no patient developed HBV reactivation. Conclusion: JAK inhibitor therapy appears to be safe in rheumatological patients who receive appropriate prophylaxis after HBV serological screening. Regular monitoring of at-risk patients is effective in preventing HBV reactivation.