Evaluation of Newly Proposed Remission Cut-points for Disease Activity Score in 28 Joints (DAS28) in Rheumatoid Arthritis upon IL-6 Pathway Inhibition
DAS28 is not currently included in the joint remission definitions of the ACR and the EULAR because its formula is disproportionately influenced by Acute Phase Response (APR).
IL-6 pathway blockers or JAK inhibitors greatly reduce APR, causing patients to be classed as in DAS28 remission despite still having multiple swollen joints.
To make DAS28 remission criteria more stringent, the alternative cut-points of <1.9 and <2.2 for CRP and ESR, respectively, have been proposed.
This study questioned the legitimacy of the new DAS28 criteria by evaluating the remission data of 2423 patients across 24 weeks’ treatment in the LITHE, OPTION and TOWARD studies, which looked at tocilizumab treatment in patients with RA.
The new criteria determined 178 (CRP) and 235 (ESR) patients to be in remission. However, almost 15% of DAS28 remitters still had ≥3 swollen joints, and only 47.2% and 52.8% achieved remission in CDAI and SDAI, respectively. This was made possible by the low APR compensating for the high joint counts; allowing DAS28 remission to be maintained
This study has justified the ACR and EULAR decision not to include DAS28 in the joint remission definitions, as even these newly proposed stringent cut-off points do not allow DAS28 remission to comply with full clinical remission defined as a state of no/minimal activity.