Abatacept (Orencia, Bristol-Myers Squibb) is the first T-lymphocyte co-stimulation modulator to be approved by FDA. The agent is indicated for use in patients with moderate-to-severe, active rheumatoid arthritis who have not had an adequate response to methotrexate, tumor necrosis factor (TNF) inhibitors, or other disease-modifying anti-rheumatic drugs (DMARDs).