Drug class: T-cell co-stimulation modulators Mechanism of Action Abatacept is a T-cell co-stimulation modulator that binds to CD80/CD86, inhibiting interaction with the CD28 receptor on T cells. This interrupts co-stimulation and T-cell activation, inhibiting major pro-inflammatory cytokines, specifically TNF-α, interferon-γ, and IL-2 (1). Approved Indications Adults with moderate to severe active rheumatoid arthritis (RA) (1) Pediatric patients (≥2 years) with moderate to se