Just because nobody complains it doesn’t mean all parachutes are perfect. — Benny Hill While there has been an expansion in therapeutic targets and a renaissance of novel therapies in psoriatic arthritis (PsA)1, the efficacy and safety of tumor necrosis factor inhibitors (TNFi) in PsA have long been established2,3. With an influx of “cheaper” biosimilars attractive to regulators and reimbursers, it behooves rheumatologists spoiled with choice to maximize efficient use of readily accessible agents. Immunogenicity due to anti-drug antibodies (ADAb) in TNFi therapy has been shown to affect drug levels and subsequently to affect clinical response in rheumatoid arthritis (RA)4 and inflammatory bowel disease5. In turn it affects safety, inducing infusion and injection site reactions (ISR), but the issue has been less well studied in patients with PsA.