Monitoring Drug and Antidrug Levels: A Rational Approach in Rheumatoid Arthritis Patients Treated with Biologic Agents Who Experience Inadequate Response While Being on a Stable Biologic Treatment

Table 2

EULAR responses at next reevaluation after first RA flare.

	EULAR response
	No	Moderate	Good	𝑃
RTX
Group A	4 (16%)	5 (20%)	7 (28%)	0.038
Group B	6 (24%)	2 (10%)	1 (4%)
IFX
Group A	2 (10%)	5 (25%)	2 (10%)	0.002
Group B	10 (50%)	1 (5%)	0
ETN
Group A	3 (16.67%)	5 (27.78%)	7 (38.89%)	0.023
Group B	3 (16.67%)	0	0
ADL
Group A	2 (22.22%)	1 (11.11%)	5 (55.56%)	0.194
Group B	1 (11.11%)	0	0

Differences between EULAR responses in group A and group B were tested using Kruskal-Wallis test, for each biologic agent.
RTX: rituximab; IFX: infliximab; ETN: etanercept; ADL: adalimumab.
Group A: detectable drug level; Group B: undetectable drug level.