Background Prevalence rate of hepatitis B virus (HBV) infection in China (13%) and many other developing countries are much higher than that in developed countries. When anti-TNF agents are more available and affordable in developing countries, the safety of anti-TNF therapy in terms of reactivation of hepatitis B infection needs more concern. No data from a prospective study focus on the use of TNF antagonists in patients with concurrent rheumatoid arthritis (RA) and HBV infection is available by now.

Objectives To evaluate the influence of Adalimumab on reactivation of HBV infection in HBsAg carriers with RA.

Methods In this 52 weeks observation, HBsAg carriers with active RA (DAS28>5.1) despite failed combined treatment with MTX and other non-biological DMARD were enrolled. Patients must have normal liver function prior to the study. All patients received therapy with Adalimumab (40mg/week) and a low dose concomitant MTX (10-12.5mg). Lamivudin were prescribed preventively regardless of individual viral load. Pre-existing NSAIDs and corticosteroids (a maximum prednisone-dose equivalent of 10 mg/day) were allowed. During the study, serum aspartate aminotransferase (AST), alanine aminotransferase (ALT) and HBV viral load (polymerase chain reaction) were monitored every 4 weeks. Increased viral load and abnormal liver function were managed and monitored according to expert opinion.

Results Ten female patients were recruited. At baseline, three patients (group 1) had increased viral load (6.8e4, 5.3e5, 7.1e4 copy/ml, respectively), and the other seven patients (group 2) had normal viral load (<100 copy/ml). Two patient from group 2 discontinued Adalimumab at week 6 due to ineffectiveness. Reactivation of hepatitis B occurred in one patient from group 1. At week 14, the patient (baseline viral load 6.8e4) underwent a mild increase of both ALT and AST (78 and 60 IU/L, respectively). A elevated viral load (7.4e7) and a HBV YMDD mutant were also found. The Adalimumab treatment continued. After prescription of Adefovir (combined with the pre-existing Lamivudin), both liver enzyme and viral load decreased to normal range in 8 weeks and remained normal. In the other two patients from group 1 and all patients from group 2, no significant increase of AST/ALT or viral load was seen during the 52 weeks follow-up.

Conclusions A aggressive Adalimumab + MTX therapy may be a safe option for HBsAg carriers with DMARDs refractory RA. In order to reduce the risk of reactivation of hepatitis B infection, prophylaxis strategy with more effective anti-viral drugs is recommended. Large cohorts are highly needed to further evaluate the use of anti-TNF agents in patients with concurrent rheumatic diseases and different HBV infection status, including inactive and active infection.

Disclosure of Interest None declared