To the Editor:
In their editorial in the June 2009 issue of The Journal, Wendling, et al1 cited our report as evidence that tocilizumab had been used uneventfully for more than 5 years to treat a patient with rheumatoid arthritis (RA) who was a hepatitis B virus (HBV) carrier2. However, they misunderstood that our patient had received tocilizumab along with prophylactic entecavir throughout her treatment. Actually, we started tocilizumab in August 2001, without confirming her HBV status. After she was incidentally found to be HBV-positive in March 2008, we added treatment with entecavir from May 2008. Recently, serum from this patient stored in 1999 was reexamined, showing that HBsAg was already positive and the viral load was quite high (3.9 × 109 copies/ml) at that time. In other words, HBV infection already existed before the initiation of tocilizumab therapy, and she was treated with tocilizumab for almost 7 years without entecavir. This was an unusual case because her viral load was high, HBeAg was positive, and anti-HBe was negative. Hence, our patient is quite different from previous cases with respect to both her viral status and the use of antiviral therapy3.
We did not report that tocilizumab can be safely administered to HBV-positive patients. Instead, we consider our case to be exceptional. Although entecavir has a high genetic barrier to resistance, the longterm effects are still unknown4. When biologic agents are needed in HBV-positive patients with rheumatic diseases, even if they are inactive carriers, the benefits of treatment versus the risks of reactivation over the long term need to be carefully weighed.
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