Infliximab Drug Level, Trough Infliximab, ANTI-TNF ALPHA

Immunology

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Description

TNF alpha is a pro-inflammatory cytokine that is involved in establishing and sustaining inflammatory reactions. Infliximab is a chimeric monoclonal antibody directed towards TNF alpha [1,2,3]. It is a useful biological therapy for chronic inflammatory conditions such as Crohns disease, ulcerative colitis and rheumatic diseases [4]. Infliximab inhibits the production of TNF alpha, therefore leading to a reduction in disease symptoms. The therapeutic effect of the drug depends upon circulating levels in the blood stream. Monitoring trough drug levels whilst establishing a dose regime can aid in determining if a therapeutic level (3-7mg/L) has been reached. Reduced trough levels (<3mg/L) may be due to insufficient dosing or due to the development of anti-drug antibodies (ADAs) which prevent the drug from working effectively. It is recommended that ADAs be measured if the trough infliximab level is <3mg/L or if an adverse reaction is observed post infusion. Supratherapeutic trough levels (>7mg/L) indicate that Infliximab has been given at a higher dose than required in that patient.

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Indications

Monitoring trough infliximab levels.

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Sample Type

Serum (Gel 5ml Yellow) or Plasma (2mL EDTA). Requests from outside Sheffield: Transport at ambient temperature via Royal Mail or Courier.

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Reference Range

Suboptimal trough level: <3mg/L.Therapeutic trough level: 3-7mg/L.Supratherapeutic trough level: >7mg/L.

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Turnaround Time

Within 10 days

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Testing Frequency

As required

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References

Lee LY, Sanderson JD and Irving PM. Anti-infliximab antibodies in inflammatory bowel disease: prevalence, infusion reactions, immunosuppression and response, a meta-analysis. Eur J Gastroenterol Hepatol. 2012. 24(9):1078-1085. [Ref 1].Steenholdt C, Bendtzen K, Brynskov J, et al. Measurement of infliximab and anti-infliximab antibody levels can help distinguish maintenance versus loss of response. Gastroenterol Hepatol. 2012. 8(2): 131-134. [Ref 2].Hendy P. Infliximab and anti-infliximab antibody levels in Crohns disease. Frontline Gastroenterol. 2014. 0: 1-2. [Ref 3].Krintel SB, Grunert VP, Hetland ML, et al. The frequency of anti-infliximab antibodies in patients with rheumatoid arthritis treated in routine care and the associations with adverse drug reacitons and treatment failures. Rheumatology. 2013. 52(7): 1245-1253. [Ref 4].

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See Also

Infliximab antibodies

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