title: Sustainable Efficacy of Switching From Intravenous to Subcutaneous Tocilizumab Monotherapy in Patients With Rheumatoid Arthritis.
abstract: OBJECTIVE
  To evaluate the efficacy and safety of switching from intravenous (IV) tocilizumab (TCZ) to subcutaneous (SC) TCZ monotherapy in rheumatoid arthritis patients.
  
  
  METHODS
  Patients who had completed 24 weeks of TCZ-SC (162 mg/2 weeks) or TCZ-IV (8 mg/kg/4 weeks) monotherapy in the double-blind period of the MUSASHI study were enrolled in an 84-week open-label extension period. All received TCZ-SC (162 mg/2 weeks) monotherapy. Effects of the IV to SC switch were evaluated at week 36 (12 weeks after switching).
  
  
  RESULTS
  Overall, 319 patients received ≥1 dose of TCZ-SC during the open-label extension period; 160 switched from TCZ-IV to TCZ-SC (TCZ IV/SC) and 159 continued TCZ-SC (TCZ SC/SC). Disease Activity Score in 28 joints using the erythrocyte sedimentation rate clinical remission rates were 62.5% (100 of 160) for TCZ IV/SC and 50.0% (79 of 158) for TCZ SC/SC at week 24, and were maintained at 62.5% (100 of 160) and 57.0% (90 of 158), respectively, at week 36. In the TCZ IV/SC group, 9% of patients (9 of 100) who had achieved remission at week 24 could not maintain remission at week 36. In TCZ IV/SC patients weighing ≥70 kg, the percentage with a sufficient serum TCZ concentration (≥1 μg/ml) decreased from 90.9% (10 of 11) at week 24 to 45.5% (5 of 11) at week 36. Overall safety profiles were similar in TCZ IV/SC and TCZ SC/SC except for mild injection site reactions in TCZ IV/SC.
  
  
  CONCLUSIONS
  Efficacy is adequately maintained in most patients switching from TCZ-IV (8 mg/kg/4 weeks) to TCZ-SC (162 mg/2 weeks) monotherapy. Patients receiving TCZ-IV can switch to TCZ-SC without serious safety concerns. Clinical efficacy may be reduced after switching in some patients with high body weight.
authors.affiliation: Osaka University, Osaka, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Ogata
authors.affiliation: Hokkaido University, Hokkaido, Japan.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Atsumi
authors.affiliation: Kurume University School of Medicine, Fukuoka, Japan.
authors.forename: Takaaki
authors.initials: T
authors.lastname: Fukuda
authors.affiliation: Hikarigaoka Spellman Hospital, Miyagi, Japan.
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Hirabayashi
authors.affiliation: Osaka City University, Osaka, Japan.
authors.forename: Masaaki
authors.initials: M
authors.lastname: Inaba
authors.affiliation: Nagoya University, Aichi, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Ishiguro
authors.affiliation: National Hospital Organization Mie Chuo Medical Center, Mie, Japan.
authors.forename: Motokazu
authors.initials: M
authors.lastname: Kai
authors.affiliation: Kyoto University, Kyoto, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Kawabata
authors.affiliation: Nagoya Medical Centre, Aichi, Japan.
authors.forename: Daihei
authors.initials: D
authors.lastname: Kida
authors.affiliation: Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Kohsaka
authors.affiliation: National Hospital Organization, Chiba-East National Hospital, Chiba, Japan.
authors.forename: Ryutaro
authors.initials: R
authors.lastname: Matsumura
authors.affiliation: Jichi Medical University, Tochigi, Japan.
authors.forename: Seiji
authors.initials: S
authors.lastname: Minota
authors.affiliation: Sapporo City General Hospital, Hokkaido, Japan.
authors.forename: Masaya
authors.initials: M
authors.lastname: Mukai
authors.affiliation: University of Tsukuba, Ibaraki, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Sumida
authors.affiliation: Dogo Spa Hospital, Ehime, Japan.
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Takasugi
authors.affiliation: Nagoya Rheumatology Clinic, Nagoya, Japan.
authors.forename: Shigenori
authors.initials: S
authors.lastname: Tamaki
authors.affiliation: Keio University, Tokyo, Japan.
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Takeuchi
authors.affiliation: Yokohama City University, Kanagawa, Japan.
authors.forename: Atsuhisa
authors.initials: A
authors.lastname: Ueda
authors.affiliation: University of Tokyo, Tokyo, Japan.
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Yamamoto
authors.affiliation: Tokyo Women's Medical University, Tokyo, Japan.
authors.forename: Hisashi
authors.initials: H
authors.lastname: Yamanaka
authors.affiliation: Kyoto University, Kyoto, Japan.
authors.forename: Hajime
authors.initials: H
authors.lastname: Yoshifuji
authors.affiliation: Chugai Pharmaceutical, Tokyo, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Nomura
mesh_terms: D000328:Adult; D061067:Antibodies, Monoclonal, Humanized / Q000008:administration & dosage* / Q000009:adverse effects; D001172:Arthritis, Rheumatoid / Q000175:diagnosis* / Q000188:drug therapy*; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007275:Injections, Intravenous; D007279:Injections, Subcutaneous; D007564:Japan; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D017060:Patient Satisfaction / Q000706:statistics & numerical data; D016059:Range of Motion, Articular / Q000187:drug effects*; D012720:Severity of Illness Index; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D061067:Antibodies, Monoclonal, Humanized; C502936:tocilizumab
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