Patients non-responding to etanercept obtain lower etanercept concentrations compared with responding patients.

Abstract

OBJECTIVE:

To investigate the relationship between serum etanercept levels and clinical response.

METHODS:

In 292 etanercept-treated patients with rheumatoid arthritis clinical and pharmacological data were determined at baseline and after 1, 4 and 6 months of etanercept treatment. Differences in etanercept levels between good, moderate and European League Against Rheumatism (EULAR) non-responders were assessed after 6 months of therapy.

RESULTS:

After 6 months of therapy etanercept levels were significantly higher in good responders (median (IQR) 3.78 (2.53-5.17)) compared with both moderate 3.10 (2.12-4.47) and EULAR non-responders 2.80 (1.27-3.93) (all p<0.05). There was a significant association between clinical response and serum etanercept levels (regression coefficient 0.54, 95% CI 0.21 to 0.86, p=0.001). When patients were categorised into quartiles according to the height of etanercept levels, the lowest quartile (etanercept level <2.1 mg/l) comprised 40% of all non-responders. The highest quartile (etanercept level >4.7 mg/l) comprised 35% of all good EULAR responders. Anti-etanercept antibodies were detected in none of the sera.

CONCLUSION:

The authors demonstrated that lower etanercept levels were associated with non-response. Therapeutic drug monitoring and the possibility of the adjusted dosing regimes in the selected groups of patients should be investigated further as a possible tool to optimise treatment with etanercept.

• Authors: A Jamnitski, C L Krieckaert, M T Nurmohamed, M H Hart, B A Dijkmans, L Aarden, A E Voskuyl, G J Wolbink
• Journal: Annals of the rheumatic diseases (Ann Rheum Dis) Vol. 71 Issue 1 Pg. 88-91 (Jan 2012) ISSN: 1468-2060 [Electronic] England
• PMID: 21914626 (Publication Type: Clinical Trial, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Antirheumatic Agents
• Immunoglobulin G
• Receptors, Tumor Necrosis Factor
• Tumor Necrosis Factor-alpha
• Etanercept

Topics

• Adult
• Aged
• Antirheumatic Agents (blood, immunology, therapeutic use)
• Arthritis, Rheumatoid (blood, drug therapy)
• Drug Monitoring (methods)
• Etanercept
• Female
• Follow-Up Studies
• Humans
• Immunoglobulin G (administration & dosage, blood, immunology)
• Male
• Middle Aged
• Receptors, Tumor Necrosis Factor (administration & dosage, blood, immunology)
• Severity of Illness Index
• Treatment Failure
• Tumor Necrosis Factor-alpha (antagonists & inhibitors)