Comparative effectiveness of TNF inhibitor vs IL-6 receptor inhibitor as monotherapy or combination therapy with methotrexate in biologic-experienced patients with rheumatoid arthritis: An analysis from the CorEvitas RA Registry
Authors: Sebba Anthony , Bingham Clifton O. , Bykerk Vivian P. , Fiore Stefano , Ford Kerri , Janak Jud C. , Pappas Dimitrios A. , Blachley Taylor , Dave Swapna S. , Kremer Joel M. , Yu Miao , Choy Ernest 
Published: April 2023

Abstract

Objective
Randomized controlled trials (RCTs) in biologic-naïve rheumatoid arthritis (RA) patients with high disease activity and inadequate response/intolerance to methotrexate have shown interleukin-6 (IL-6) receptor inhibitors (IL-6Ri) to be superior to tumor necrosis factor inhibitors (TNFi) as monotherapy. This observational study aimed to compare the effectiveness of TNFi vs IL-6Ri as mono- or combination therapy in biologic/targeted synthetic (b/ts) -experienced RA patients with moderate/high disease activity.

Methods
Eligible b/ts-experienced patients from the CorEvitas RA registry were categorized as TNFi and IL-6Ri initiators, with subgroups initiating as mono- or combination therapy. Mixed-effects regression models evaluated the impact of treatment on Clinical Disease Activity Index (CDAI), patient-reported outcomes, and disproportionate pain (DP). Unadjusted and covariate-adjusted effects were reported.

Results
Patients initiating IL-6Ri (n = 286) vs TNFi monotherapy (n = 737) were older, had a longer RA history and higher baseline CDAI, and were more likely to initiate as third-line therapy; IL-6Ri (n = 401) vs TNFi (n = 1315) combination therapy initiators had higher baseline CDAI and were more likely to initiate as third-line therapy. No significant differences were noted in the outcomes between TNFi and IL-6Ri initiators (as mono- or combination therapy).

Conclusion
This observational study showed no significant differences in outcomes among b/ts-experienced TNFi vs IL-6Ri initiators, as either mono- or combination therapy. These findings were in contrast with the previous RCTs in biologic-naïve patients and could be explained by the differences in the patient characteristics included in this study. Further studies are needed to help understand the reasons for this discrepancy in the real-world b/ts-experienced population.

Key Points• Patients with rheumatoid arthritis (RA) often require switching between biologics or targeted synthetic (b/ts) disease-modifying anti-rheumatic drugs (DMARDs) to achieve their treatment target.• Head-to-head randomized controlled trials (RCTs) in biologic-naïve RA patients with high disease activity and inadequate response/intolerance to methotrexate have shown interleukin-6 receptor inhibitors (IL-6Ri) to be superior to tumor necrosis factor inhibitors (TNFi) as monotherapy; however, there are no RCTs comparing these therapies in a population previously treated with b/tsDMARDs (i.e., b/ts-experienced patients).• This observational study compared the effectiveness of TNFi vs IL-6Ri (as mono- or combination therapy) in b/ts-experienced RA patients with moderate or high disease activity and found no significant differences in clinical outcomes for the two treatments.• A discrepancy is noted between our study and RCTs, which have shown superiority of IL-6Ri therapy (albeit in biologic-naïve patients). Further analyses may help elucidate the reason for this discrepancy in the real-world b/ts-experienced population.