Response to viewpoint ‘Defining refractory rheumatoid arthritis’ by Buch

With great interest, we read the clinically highly relevant viewpoint on ‘Defining refractory rheumatoid arthritis’ by Professor Maya H. Buch.1 The author classifies refractory rheumatoid arthritis (RA) into ‘intrinsic refractory’ (persistent inflammation, no antidrug antibodies (ADA)), ‘pharmacokinetic refractory’ (persistent inflammation, presence of ADA) or ‘false positive refractory’ (no persistent inflammation, no ADA). Professor Buch highlights the gap of knowledge in the understanding of refractory RA and states that consistent definitions and criteria are required for future research. We fully agree with the author that this subpopulation of patients with RA is facing unmet needs, …