Why we use tocilizumab in RA?

Abstract

  Humanized IL-6 receptor antibody, Tocilizumab（TCZ）is an inhibitor of IL-6, which plays an important role in the pathogenesis of rheumatoid arthritis（RA）. TCZ improves RA symptoms including joint destruction in MTX naïve, inadequate response（IR）to DMARDs, MTX and TNF inhibitors. The efficacy is comparable to other biologics. Especially, TCZ has a significant advantage in a monotherapy setting. However, the efficacy of TCZ to Ankylosing Spondylitis and Psoriatic Arthritis is unfavorable. Since TCZ hides CRP, CRP is useless for evaluation of disease activity or infection during TCZ therapy. Generation of neutralization antibody is rare and long-term retention of TCZ is favorable. However, trial of TCZ-free remission is an unfavorable outcome. So, beyond remission, tapering or extension of the interval of TCZ is a better choice than cessation. The most notable safety problem is infection. In particular, hidden or weakening symptoms of infection during TCZ therapy cause delayed treatment and critical illness. Finally, chooseable administration routes and economical advantages（in Japan）also make TCZ is an attractive alternative biologic to RA.