Switching Between TNF Inhibitors in Psoriatic Arthritis: Data from the NOR-DMARD Study

Background: Tumour necrosis factor inhibitors (TNFi) are efficacious in patients with psoriatic arthritis (PsA), but some patients do not respond or do not tolerate their first TNFi, and are switched to a different TNFi. Evidence supporting this practice is limited, and we wanted to investigate the effectiveness of switching to a second TNFi.

Material And Methods: From a longitudinal observational study (LOS) we selected patients with PsA who were starting their first TNFi, and identified patients who had switched to a second TNFi ('switchers'). Three-month responses and 3-year drug-survival were compared between switchers and non-switchers, and within switchers.

Results: Switchers (n=95) receiving their second TNFi had significantly poorer responses compared with non-switchers (n=344) (ACR50 response: 22.5% vs 40.0%, DAS28 remission: 28.2% vs 54.1%). There was a trend towards poorer responses to the second TNFi compared with the first TNFi within switchers. Estimated 3-year drug-survival was 36% for the second TNFi compared with 57% for the first TNFi overall.

Conclusions: 20-40% of patients had a response on a second TNFi after having failed one TNFi in this LOS. This observation highlights the need for treatments with other mechanisms of action than TNF inhibition in patients with PsA.