Therapeutic Drug Monitoring (TDM) in IBD
Anti-TNFs, Biologics, Therapeutic drug monitoring
- 43 year old with Crohn’s disease on adalimumab/Humira but now has developed a loss of response.
- Low trough level and elevated antibody: what is next?
- Who checks levels and when do you check levels? We need to understand that ‘one size doesn’t fit all’ and therefore TDM should be routinely practiced.
- Which assay do you typically use? This depends on your institution, patient’s insurance and costs.
- How do you interpret the drug and antibody levels?
- Low drug level, low/undetectable antibodies -> dose escalate anti TNF
- Normal drug level, detectable antibodies -> maximize anti-TNF efficacy, consider IMM; consider switch to another anti-TNF or out of class biologic
- Normal drug level, low/undetectable antibodies -> evaluate for active disease, scope, imaging
- When do you consider combination therapy with an immunomodulator and biologic agent? Based on clinical symptoms, severity of symptoms, age, predictors of severe disease, response to treatment
- Who has used the newer assays – vedolizumab, certolizumab? Newer assays are now available
Consensus: TDM is an important clinical practice for IBD management of response to treatment and consideration of change in treatment. One dose isn’t for all.