Therapeutic drug monitoring of anti-TNF drugs: an overview of applicability in daily clinical practice in the era of treatment with biologics in juvenile idiopathic arthritis (JIA)

Table 2 Patient drug levels and anti-drug antibodies

		Subgroup analysis with trough levels
Anti TNF, no. of drug levels/no. of patients^a
Etanercept	21/15	6/6
Adalimumab	51/38	22/21
Infliximab	70/28	70/28
Drug levels, median (range / IQR)
Etanercept	2.4 (0.0–8.1 / 1.8–3)	2.2 (0.9–2.7 / 0.9–2.9)
Adalimumab	12 (0–49 / 4.8–15)	10.2 (0–27 / 0.01–14)
Infliximab	16 (0–81 / 7.3–23)	16 (0–81 / 7.3–23)
Therapeutic drug levels^b (% per drug group)
Etanercept		3 (50%)
Adalimumab		0 (0%)
Infliximab		11 (16%)
Subtherapeutic drug levels^b
Etanercept		2 (33%)
Adalimumab		9 (41%)
Infliximab		5 (7%)
Supratherapeutic drug levels^b
Etanercept		1 (17%)
Adalimumab		13 (59%)
Infliximab		53 (77%)
Antidrug antibodies (% of patients using that drug)
Adalimumab	7 (18.4%)
Infliximab	1 (4%)

^a A few patients had received more than one anti-TNF drug on different time points
^b according to adult data in RA and IBD; therapeutic drug levels for JIA are not yet determined

ISSN: 1546-0096