Phase II dose-response study of abatacept in Japanese patients with active rheumatoid arthritis with an inadequate response to methotrexate.
OBJECTIVE
The objective of this study was to assess the response to abatacept at doses of 2 mg/kg and 10 mg/kg compared to placebo in patients with active rheumatoid arthritis (RA) with an inadequate clinical response to methotrexate (MTX).


METHODS
In this multicenter, placebo-controlled, double-blind, parallel-group, dose-response study, 195 Japanese patients with active RA with an inadequate response to MTX were randomized 1:1:1 to receive 10 mg/kg or 2 mg/kg abatacept plus MTX, or placebo plus MTX, for 24 weeks.


RESULTS
Abatacept demonstrated a dose-response relationship when given at 2 and 10 mg/kg. Based on the American College of Rheumatology criteria (20, 50, and 70 %), the responses to 10 mg/kg abatacept were significantly greater than those to placebo at week 24 (p < 0.001). Smaller yet statistically significant responses were also seen in the 2 mg/kg abatacept group. Overall rates of adverse events, serious adverse events, and treatment discontinuations because of adverse events were comparable in all three groups.


CONCLUSIONS
Abatacept (2 mg/kg and 10 mg/kg) showed a dose-response relationship in Japanese patients with active RA with an inadequate clinical response to MTX. Administration of abatacept in combination with MTX for 24 weeks was well tolerated.
Division of Rheumatology, Department of Internal Medicine, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan. tsutake@z5.keio.jp
Tsutomu
T
Takeuchi
Tsukasa
T
Matsubara
Taisuke
T
Nitobe
Eiichi
E
Suematsu
Syuji
S
Ohta
Shigeru
S
Honjo
Tohru
T
Abe
Ami
A
Yamamoto
Nobuyuki
N
Miyasaka
D000069594:Abatacept; D018501:Antirheumatic Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D001172:Arthritis, Rheumatoid / Q000188:drug therapy*; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D006801:Humans; D018796:Immunoconjugates / Q000008:administration & dosage / Q000627:therapeutic use*; D007564:Japan; D008727:Methotrexate / Q000008:administration & dosage / Q000627:therapeutic use*; D019233:Retreatment; D016896:Treatment Outcome
D018501:Antirheumatic Agents; D018796:Immunoconjugates; D000069594:Abatacept; D008727:Methotrexate