Currently, anti-TNF biological treatment decisions for people with Crohn's disease (CD) are based on clinical judgement and 'trial and error'. As a result, people whose disease responds well to a tumour necrosis factor (TNF) inhibitor drug may continue receiving the same level of drug even when it may be possible to reduce the dose or withdraw the drug without having any detrimental effect on clinical outcomes. Loss of response (LOR) is typically treated with a higher dose of drug to try to recover a clinical response. This approach can be successful for some people, but for others, the intensified regimen is ineffective as they receive an expensive drug that gives them no benefit and may cause unnecessary side effects.
Measuring levels of anti-TNF drugs and associated antibodies (a process known as Therapeutic Drug Monitoring, TDM) in blood could help clinicians to identify the best treatment strategy for a person with CD. Commercial test kits have been developed that are used for TDM in CD. Although there is evidence that such testing improves patient outcomes and is cost-effective they are not routinely used to optimise treatment mainly due to the heterogeneity of the assays that can lead to discrepancy in the results.
This study plans to address the following questions:
1) Does standardisation through use of common reference material improve the correlation between the kits and harmonise the results?
2) What is the value of TDM in treatment decision-making for people with CD who are losing response?
3) What is the clinical and cost-effectiveness of TDM in people with CD whose disease responds to treatment?
Study status: The study protocol has been submitted to a journal for publication and is currently at the review stage.