Abatacept for the Treatment of Giant Cell Arteritis

Participants randomized to abatacept will receive abatacept 125 mg administered by subcutaneous injection once a week. Participants randomized to either the abatacept or the placebo arm who experience a non-severe disease relapse, non-severe disease worsening, or who have not achieved remission by month 3 will have the option of entering an open-label trial period whereby they would receive open-label abatacept for up to 12 months.

Participants randomized to placebo will receive a sterile placebo solution administered by subcutaneous injection once a week. Participants randomized to either the abatacept or the placebo arm who experience a non-severe disease relapse, non-severe disease worsening, or who have not achieved remission by month 3 will have the option of entering an open-label trial period whereby they would receive open-label abatacept for up to 12 months.