Tocilizumab has demonstrated optimal efficacy and safety in patients with rheumatoid arthritis (RA) from clinical trials. However, the risk of hepatitis B virus reactivation (HBVr) in these patients remains uncertain because patients with underlying HBV have been excluded in phase III studies.
Systematical reviews were conducted on PubMed, Embase, and the Cochrane Central Register of Controlled Trials up to 21 February 2023. Random-effects meta-analysis was performed to calculate the pooled incidence of HBV reactivation.
We included 0 clinical trials and 11 observational studies with a total of 25 HBsAg+ and 322 HBsAg-/anti-HBc+ RA patients. Among the HBsAg+ patients without antiviral prophylaxis, the pooled rate was 69.4% (95% CI, 32.9-91.3), with a median time of 4 months (range, 1-8 months) from tocilizumab initiated. Half of these patients with HBVr experienced hepatitis flare-up but no deaths. HBVr was eliminated with prophylaxis in this population. Among HBsAg-/anti-HBc+ patients, the pooled incidence of reactivation was 3.3% (95% CI, 1.6-6.7), with a median time of 10 months (range, 2-43 months) from tocilizumab initiated. HBVr was not associated with hepatitis flare-up and death. HBsAg-/anti-HBc+ patients without anti-HBs antibodies had a significantly higher risk of HBVr (Odds ratio, 12.20; 95% CI, 1.16-128.06).
This systematic review indicated that the risk of HBVr in RA patients with anti-HBs-, HBsAg+, or HBsAg-/anti-HBc+ cannot be ignored but may be avoided. Clinicians should consider implementing appropriate antiviral prophylaxis and monitoring policies for RA patients to avoid unnecessary hepatic side effects from tocilizumab treatment.

BACKGROUND: Rheumatoid arthritis (RA) patients seropositive for hepatitis B core antibody (HBcAb) and negative for hepatitis B surface antigen (HBsAg) are at risk of hepatitis B virus (HBV) reactivation when treated with biologic or targeted synthetic (b/ts) disease-modifying antirheumatic drugs (DMARDs). The study aims to investigate the risk in this population.
METHODS: From January 2004 through December 2020, 1068 RA patients undergoing b/tsDMARDs therapy and 416 patients with HBsAg-/HBcAb+ were enrolled. Factors associated with HBV reactivation were analysed.
RESULTS: During 2845 person-years of follow-up, 27 of 416 (6.5%,9.5 per 1000 person-years) patients developed HBV reactivation, with a cumulative rate of HBV reactivation of 3.5% at 5 years, 6.1% at 10 years and 24.2% at 17 years. The median interval from beginning b/tsDMARDs to HBV reactivation was 85 months (range: 9-186 months). The risk of HBV reactivation varied by type of b/tsDMARD, with rituximab having the highest risk (incidence rate: 48.3 per 1000 person-years), followed by abatacept (incidence rate: 24.0 per 1000 person-years). In multivariate analysis, rituximab (adjusted hazard ratio [aHR]: 15.77, 95% confidence interval [CI]: 4.12-60.32, p = .001), abatacept (aHR: 9.30, 1.83-47.19, p = .007), adalimumab (aHR: 3.86, 1.05-14.26, p = .04) and negative baseline HBV surface antibody (anti-HBs, <10 mIU/mL) (aHR: 3.89, 1.70-8.92, p < .001) were independent risk factors for HBV reactivation.
CONCLUSIONS: HBsAg-/HBcAb+ RA patients are susceptible to HBV reactivation during b/tsDMARD therapy. Those with negative baseline anti-HBs and those on certain b/tsDMARDs, such as rituximab, abatacept and adalimumab, have high reactivation risks. Risk stratification and management should be based on the patient\'s baseline anti-HBs titre and type of therapy.

To investigate the risk of hepatitis B virus reactivation in patients undergoing long-term tocilizumab therapy for rheumatoid arthritis.
From January 2011 through August 2019, a total of 97 patients were enrolled in this retrospective study. Clinical data, comedications, and the occurrence of HBV reactivation were recorded.
Seven patients were HBsAg+ (7.2%), 64 were HBsAg-/HBcAb+ (65.9%), and 26 were HBsAg-/HBcAb- (26.8%). The median disease follow-up time was 9 years. TCZ was administered for a median of 29 months. Four patients (4.1%) experienced HBV reactivation after tocilizumab therapy. Of the 7 HBsAg+ patients, 4 received antiviral prophylaxis and had no HBV reactivation; the remaining 3 patients did not receive antiviral prophylaxis, and all 3 (100%) experienced HBV reactivation and hepatitis flare-up. Hyperbilirubinemia occurred in 2 of these 3 patients, with mild prothrombin time prolongation in one. After salvage entecavir treatment, all patients had a favorable outcome. Of the 64 HBsAg-/HBcAb+ patients, only one became positive for serum HBV DNA (2.5 × 107 IU/mL) after 18 months of tocilizumab treatment (1.6%; 1/64). This patient was immediately treated with entecavir, which prevented hepatitis flare-up.
Tocilizumab is widely used in treating rheumatoid arthritis and has the potential to reduce the mortality rate among severe COVID-19 patients. However, HBV reactivation needs to be considered. HBsAg+ patients have a high risk of HBV reactivation, which could be prevented by antiviral prophylaxis. Although the risk of reactivation is low in HBsAg-/HBcAb+ patients, strict monitoring is necessary.