Biologic
RCSB PDB 3OSK
Abatacept
Orencia
- Mechanism of action
- CTLA-4-Ig fusion protein (T-cell costimulation blocker)
- In plain language
- A lab-made fusion protein that steps into an immune handshake between cells, blocking the second signal T-cells need to fully switch on, calming the overactive immune response that drives joint inflammation.
- How it works
- Abatacept is a soluble fusion protein combining the extracellular domain of human CTLA-4 with a modified Fc portion of human IgG1. It binds CD80 and CD86 on antigen-presenting cells, competitively blocking their interaction with the CD28 costimulatory receptor on T-lymphocytes. Without this CD28 costimulatory signal, T-cells cannot achieve full activation despite receiving antigen-specific signaling through the T-cell receptor. This selective costimulation blockade dampens the pathologic T-cell activation that underlies inflammatory arthropathies and contributes to graft-versus-host disease.
- Therapeutic applications
- FDA-approved for moderately to severely active rheumatoid arthritis in adults; moderately to severely active polyarticular juvenile idiopathic arthritis and active psoriatic arthritis in patients 2 years and older; and prophylaxis of acute graft-versus-host disease in patients undergoing certain stem cell transplants.
- Class
- Fusion protein
- Therapeutic area
- Immunology
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