TNFα Drugs Help Minimize Disease Activity in PsA

December 8, 2014

Tumor necrosis factor α inhibitors achieve minimal disease activity in about two-thirds of patients with psoriatic arthritis within about a year.

Haddad A, Thavaneswaran A, Arruza IR, et al., Minimal disease activity and anti-TNF Therapy in psoriatic arthritis. Arthritis Research & Therapy. 2014 66(12)  doi: 10.1002/acr.22529. Online Dec. 2

Almost 65% of psoriatic arthritis (PsA) patients may be able to achieve minimal disease activity on tumor necrosis factor-alpha (TNFα) blockers after as little as a year, with some able to maintain it even if the drugs are reduced or stopped, according to an observational study from Canada.

Men with a normal erythrocyte sedimentation rate (ESR) seem more likely to achieve minimal disease activity (MDA) than women, but the study authors say those factors don’t appear to increase chances of maintaining MDA. 

The study involved patients from the University of Toronto Psoriatic arthritis cohort who’d been treated with TNFα inhibitors between 2000 and 2012, mostly for peripheral arthritis. Around 65% were men (mean age 49) who’d had PsA for an average of 13 years.

The 226 patients who had not reached MDA before using TNF drugs were followed with clinical exams every 6-12 months and X-rays every 2 years to map their progress and identify predictors of MDA.

Of these, 145 reached MDA and 88 achieved sustained MDA lasting 12 months or more using TNF-blockers; 81 did not reach MDA on the drugs. Eight patients were able to stop TNF therapy after a year and 9 were able to reduce their dose, but all maintained MDA for at least two years.

The authors say their study is the first to show that MDA can be reached and maintained even if TNF drugs are changed or withdrawn.

They defined MDA as meeting 5 out of 7 of the following criteria at two consecutive visits at least a year apart:

•  Tender joint count of <1
•  Swollen joint count <1
•  Tender entheseal points <1
•  A psoriasis activity and severity index (PASI) < (or a body surface area <3)
•  Patient pain visual analog scale (VAS) score <15
•  Patient global disease activity-VAS score <20
•  Health Assessment Questionnaire (HAQ) score <5;

Since more than a third did not achieve MDA, “the TNFα pathway might not have a pivotal role in driving the inflammation” in some patients, the authors note.

Remission might be a better target, they conclude, but “a definition of remission in PsA has not been uniformly accepted.”