Table 5.
Biological drug concentrations and anti-drug antibodies when applying therapeutic drug monitoring in inflammatory bowel disease.
| Statement | Vote agreement, % |
|---|---|
| A. General | |
| 13. There is no difference in indication for ordering drug/antibody concentrations or interpretation of results for biosimilars or the originator drug. | 100 (13/13) |
| 14. The threshold drug concentration may vary depending on disease phenotype and desired therapeutic outcome. | 100 (13/13) |
| 15. In the presence of adequate trough drug concentrations, anti-drug antibodies are unlikely to be clinically relevant. | 100 (12/12) |
| 16. Other than for anti-infliximab antibodies, there are not enough data to recommend a threshold for high anti-drug antibody titers for the biologic drugs. | 100 (12/12) |
| B. Infliximab | |
| 17. The current evidence suggests that the variability of infliximab concentrations between the different assays is unlikely to be clinically significant. | 100 (13/13)a |
| 18. There is insufficient evidence that inter-assay drug concentration results are comparable for biologic drugs other than for infliximab. | 100 (13/13) |
| 19. The minimal trough concentration for infliximab post-induction at week 14 should be greater than 3 μg/ml, and concentrations greater than 7 μg/ml are associated with an increased likelihood of mucosal healing. | 100 (13/13) |
| 20. During maintenance the minimal trough concentration for infliximab for patients in remission should be greater than 3 μg/ml. For patients with active disease infliximab should generally not be abandoned unless drug concentrations are greater than 10 μg/ml. | 92 (12/13) |
| 21. In the absence of detectable infliximab, high titer anti-infliximab antibodies require a change of therapy. Low level antibodies can sometimes be overcome. For the ANSER assay, a high titer anti-infliximab antibody at trough is defined as 10 U/ml, for RIDAscreen the cut-off is 200 ng/ml, for InformTx/Lisa Tracker the cut-off is 200 ng/ml. For other assays, there is insufficient data to define an adequate cut-off for a high titer anti-infliximab antibody. | 100 (13/13) |
| C. Adalimumab | |
| 22. The minimum drug concentration at week 4 for adalimumab should at least be 5 μg/ml. Drug concentrations greater than 7 μg/ml are associated with an increased likelihood of mucosal healing. | 83 (10/12)a |
| 23. During maintenance the minimum trough concentration for adalimumab for patients in remission should be greater than 5 μg/ml. For patients with active disease adalimumab should generally not be abandoned unless drug concentrations are greater than 10 μg/ml. | 100 (12/12) |
| D. Certolizumab pegol | |
| 24. The minimum concentrations for certolizumab pegol at week 6 should be greater than 32 μg/ml. | 100 (12/12) |
| 25. During maintenance the minimum trough concentration for certolizumab pegol for patients in remission should be 15 μg/ml. | 92 (11/12) |
| E. Golimumab | |
| 26. The minimum drug concentration at week 6 for golimumab should at least be 2.5 μg/ml. | 92 (11/12) |
| 27. During maintenance the minimum trough concentration for golimumab for patients in remission should be greater than 1 μg/ml. | 92 (11/12) |
| F. Vedolizumab / Ustekinumab | |
| 28. Although there are emerging data that may show an association between drug concentrations and outcomes, they are not sufficient to guide specific induction and maintenance drug concentrations for vedolizumab and ustekinumab other than confirming that there is detectable drug. | 100 (12/12) |
a
After a second round of voting.
HMSA: homogeneous mobility shift assay; TNF: tumor necrosis factor.