Abatacept (Orencia¬ģ) - Therapeutic Drug Monitoring (TDM)

Abatacept consists of the extracellular domain of human cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) linked to a modified Fc portion of human immunoglobulin G1 (IgG1). Abatacept dampens T lymphocyte-dependent antibody responses and inflammation.

Abatacept modulates a key costimulatory signal required for full activation of T lymphocytes expressing CD28. A major costimulatory pathway involves the binding of CD80 and CD86 molecules on the surface of antigen presenting cells to the CD28 receptor on T lymphocytes. Abatacept specifically binds to CD80 and CD86, thereby selectively inhibiting this costimulatory pathway.

Clinical Use

In Europe, abatacept (Orencia¬ģ) is indicated for treatment of:

  • in combination with methotrexate, active rheumatoid arthritis (RA) in adults who respond inadequately to previous therapy
  • highly active and progressive disease in adult rheumatoid arthritis methotrexate-na√Įve patients
  • in combination with methotrexate, for moderate to severe active polyarticular juvenile idiopathic arthritis in patients of at least 6 years old who respond inadequately to other therapy.

Testing abatacept concentration:

The assay is performed using Enzyme Linked Immunosorbent Assay (ELISA). The limit of quantification (LOQ) for abatacept in serum is not yet defined but is approx. 0.01 ¬Ķg/mL.

Testing abatacept anti-drug antibodies (ADA):

Not available

Clinical Relevance

No response or loss of response of treatment with abatacept.

With level testing of biologics, efficacy of therapy can be improved, as treatment decisions may need to be adapted depending on the test results in conjunction with clinical responses to treatment.

Data and interpretation of abatacept serum levels are still very limited.

Personalized Medicine

Monitoring biologic levels in individual patients allows optimization of treatment efficacy by adjusting therapy depending on the specific response of the patient. When drug levels are decreased in a non-responder, this may reflect formation of inactivating antibodies directed to the biologic treatment. Immunogenicity testing identifies presence or absence of inactivating antibodies, which guides the next treatment decision ‚Äď switch to other biological treatment, lowering of dose or intensify dosing. Reducing drug dosage in well-responding patients with relatively high drug levels cuts down cost. A personalized approach can improve therapy efficacy and quality of life.

Read more on the following pages:

Order of test: Print and complete the request form and send it together with the sample.

For further questions please contact us.

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