Last reviewed 2026-04-23 · How we verify

Open-label Abatacept

Abatacept is a fusion protein that blocks T-cell costimulation by binding to CD80/CD86 on antigen-presenting cells, thereby inhibiting T-cell activation and reducing inflammatory responses.

Abatacept is a fusion protein that blocks T-cell costimulation by binding to CD80/CD86 on antigen-presenting cells, thereby inhibiting T-cell activation and reducing inflammatory responses. Used for Rheumatoid arthritis, Polyarticular juvenile idiopathic arthritis, Psoriatic arthritis.

At a glance

Mechanism of action

Abatacept works by interrupting the second signal required for full T-cell activation. It consists of the extracellular domain of CTLA-4 fused to the Fc portion of IgG1, allowing it to bind CD80 and CD86 molecules on antigen-presenting cells. This prevents the interaction between these molecules and CD28 on T cells, effectively dampening the adaptive immune response and reducing production of inflammatory cytokines.

Approved indications

• Rheumatoid arthritis
• Polyarticular juvenile idiopathic arthritis
• Psoriatic arthritis
• Ankylosing spondylitis
• Systemic lupus erythematosus

Common side effects

• Infections (upper respiratory, urinary tract)
• Headache
• Nausea
• Dizziness
• Hypertension

Key clinical trials

• A Study to Evaluate the Benefits and Risks of Conversion of Existing Adolescent Kidney Transplant Recipients Aged 12 to <18 Years to a Belatacept-based Immunosuppressive Regimen as Compared to Continuation of a Calcineurin Inhibitor-based Regimen, and Their Adherence to Immunosuppressive Medications (PHASE3)
• Cyclophosphamide, Abatacept, and Tacrolimus for the Prevention of GvHD (PHASE2)
• Abatacept for the Treatment of Giant Cell Arteritis (PHASE3)
• Preventing Extension of Oligoarticular Juvenile Idiopathic Arthritis JIA (Limit-JIA) (PHASE3)
• A Study of TCD601 in de Novo Renal Transplant Recipients (PHASE2)
• Ruxolitinib With and Without CTLA-4 Ig Abatacept for the Prophylaxis of Graft-Versus-Host Disease and Cytokine Release Syndrome After T-cell Replete Haploidentical Peripheral Blood Hematopoietic Cell Transplantation (PHASE1)
• Open Label , Randomized, Three Arm Parallel Group Single Dose Comparative Pharmacokinetic , Safety and Immunogenicity Study in Healthy Subjects (PHASE1)
• A Study to Evaluate the Safety and Efficacy of Dual Costimulation Blockade With VIB4920 and Belatacept for Prophylaxis of Allograft Rejection in Adults Receiving a Kidney Transplant (PHASE2)

Primary sources

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