Predictive value of serum amyloid a levels for requirement of concomitant methotrexate in tocilizumab initiation: A post hoc analysis of the SURPRISE study

Masaru Kato, Yuko Kaneko, Yoshiya Tanaka, Masayuki Inoo, Hitomi Kobayashi-Haraoka, Koichi Amano, Masayuki Miyata, Yohko Murakawa, Hidekata Yasuoka, Shintaro Hirata, Hayato Nagasawa, Eiichi Tanaka, Nobuyuki Miyasaka, Hisashi Yamanaka, Kazuhiko Yamamoto, Isao Yokota, Tatsuya Atsumi^*, Tsutomu Takeuchi