Abatacept

What it is and how it works

Mechanism of Action Abatacept, a selective costimulation modulator, inhibits T-cell (T lymphocyte) activation by binding to CD80 and CD86, thereby blocking interaction with CD28. This interaction provides a costimulatory signal necessary for full activation of T lymphocytes. Activated T lymphocytes are implicated in the pathogenesis of RA, pJIA and PsA and are found in the synovium of patients with RA, pJIA and PsA. In vitro , abatacept decreases T-cell proliferation and inhibits the production of the cytokines TNF alpha (TNFα), interferon-γ, and interleukin-2.

Indications

is a selective T cell costimulation modulator indicated for: • the treatment of adult patients with moderately to severely active rheumatoid arthritis (RA). • the treatment of patients 2 years of age and older with moderately to severely active polyarticular juvenile idiopathic arthritis (pJIA). • the treatment of patients 2 years of age and older with active psoriatic arthritis (PsA). • the prophylaxis of acute graft versus host disease (aGVHD), in combination with a calcineurin inhibitor and methotrexate, in adults and pediatric patients 2 years of age and older undergoing hematopoietic stem cell transplantation (HSCT) from a matched or 1 allele-mismatched unrelated donor. Limitations of Use: Concomitant use of ORENCIA with other immunosuppressives [e.g., biologic disease-modifying antirheumatic drugs (bDMARDS), Janus kinase (JAK) inhibitors] is not recommended. ( 1.5 , 5.1) Adult Rheumatoid Arthritis ORENCIA ® is indicated for the treatment of adult patients with moderately to severely active rheumatoid arthritis (RA).

Dosage and administration (summary)

Intravenous Use for Adult RA and Adult PsA • Administer at 0, 2, and 4 weeks, and every 4 weeks thereafter, as a 30-minute infusion Body Weight of Patient Dose Number of Vials Less than 60 kg 500 mg 2 60 to 100 kg 750 mg 3 More than 100 kg 1,000 mg 4 Subcutaneous Use for Adult RA • Prior to the first subcutaneous dose, may administer an optional loading dose as a single intravenous infusion as per body weight categories above. • Administer 125 mg by subcutaneous injection once weekly (within a day of the intravenous infusion if infusion given). • Patients switching from intravenous use to subcutaneous use, administer first subcutaneous dose instead of next scheduled intravenous dose.

Contraindications

None. None.

Warnings and precautions

• Concomitant use with a TNF antagonist can increase the risk of infections and serious infections. • Hypersensitivity and anaphylaxis have occurred. • Serious infections reported. Patients with a history of recurrent infections or underlying conditions predisposing to infections may experience more infections. Discontinue if a serious infection develops. • Screen for latent TB infection prior to initiating therapy. Patients testing positive should be treated prior to initiating ORENCIA. • Screen for viral hepatitis prior to initiating ORENCIA.

Pregnancy

Pregnancy Risk Summary The data with ORENCIA use in pregnant women are insufficient to inform on drug-associated risk. However, there are clinical considerations for administering live vaccines to infants who were exposed to ORENCIA while in utero (see Clinical Considerations) .

Storage and supply

Storage Refrigerate ORENCIA lyophilized powder supplied in a vial at 2°C to 8°C (36°F to 46°F). Do not use beyond the expiration date on the vial. Protect the vials from light by storing in the original package until time of use. Refrigerate ORENCIA solution supplied in a prefilled syringe or ClickJect autoinjector at 2°C to 8°C (36°F to 46°F).

Source: Abatacept (Orencia) — US FDA prescribing information, 2025-11-13, DailyMed. Summarised and shortened; the full label governs. Iranian registration, indications and labelling may differ.