Table 3.
Pt | Dx | Anti-TNF drug | On immuno- modulator?1 | Reason for TDM | Predrug level | Pre-Ab level | Adjustment in therapy | Post- drug level | Post- Ab level | Resolved ADAs? | Did patient have improvement? |
1 | CD | ADA | N | Endoscopic disease | 3.0 μg/mL | 38 ng/mL | Frequency | 10 μg/mL | < 25 ng/mL | Y | Symptom improvement; fecal calprotectin |
2 | UC | ADA | N | Flare symptoms | < 1.6 μg/mL | 4.6 U/mL | Dose/ frequency | 13.7 μg/mL | < 1.7 U/mL | Y | Symptom |
improvement; decreased CRP | |||||||||||
3 | CD | ADA | N | Flare symptoms | 3.3 μg/mL | 2.6 U/mL | Frequency | 5.8 μg/mL | 0 | Y | Symptom |
improvement | |||||||||||
4 | CD | ADA | Y - 6MP | Flare symptoms, Endoscopic disease | 2.6 μg/mL | 66 ng/mL | Frequency | 4.8 μg/mL | < 25 ng/mL | Y | Symptom |
improvement | |||||||||||
5 | CD | IFX | N | Flare symptoms | 4.1 μg/mL | 4.5 U/mL | Dose/ frequency | 23.4 μg/mL | < 3.1 U/mL | Y | Symptom improvement; CRP |
6 | UC | IFX | Y - AZA | Flare symptoms | 1.1 μg/mL | 8.2 U/mL | Dose | 16.9 μg/mL | < 3.1 U/mL | Y | Symptom improvement |
7 | UC | IFX | N | Flare symptoms; Endoscopic disease | 10.4 μg/mL | 5.0 U/mL | Added immuno-modulator (MTX) | 11.3 μg/mL | 0 | Y | Symptom improvement; ESR |
8 | UC | IFX | Y - MTX | Flare symptoms | 0 | 5.5 U/mL | Dose | 26.8 μg/mL | 0 | Y | ESR/CRP |
9 | CD | IFX | N | Flare symptoms | 23.1 μg/mL | 8.6 U/mL | Dose | < 1 μg/mL | 88.6 U/mL | N | - |
10 | CD | IFX | N | Endoscopic disease | < 1.0 μg/mL | 3.7 U/mL | Frequency | < 0.4 μg/mL | 34 ng/mL | N | - |
11 | CD | ADA | N | Flare symptoms | 5.6 μg/mL | 3.1 U/mL | Frequency | 4.6 μg/mL | 113 ng/mL | N | - |
12 | CD | IFX | Y - MTX | Flare symptoms | < 1 μg/mL | 8.2 U/mL | Frequency | 8.2 μg/mL | 9.0 U/mL | N | - |
Refers to concurrent immunomodulator therapy. Pt: Patient; Dx: Diagnosis; TDM: Therapeutic drug monitoring; Ab: Antibody; ADA: Antidrug antibody; CD: Crohn’s disease; UC: Ulcerative colitis; ADA: Adalimumab; IFX: Infliximab; AZA: Azathioprine; 6MP: 6-mercaptopurine; MTX: Methotrexate; ESR: Erythrocyte sedimentation rate; CRP: C-reactive protein.