Long-term tumor necrosis factor-alpha inhibitor (TNFi) therapy is well-tolerated and effective in treating psoriatic arthritis (PsA), but successive TNFi switches are associated with lesser benefits and more adverse effects, according to research results published in Rheumatology Advances in Practice.

Researchers conducted a multicenter, retrospective, observational cohort study to describe the patterns of first and subsequent TNFi therapy and patient responses to long-term TNFi therapy in PsA. Owing to limited longitudinal study data, a target sample size of 150 patients was selected based on the anticipated PsA response criteria (PsARC) at 12 weeks after initiation of first TNFi.

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The cohort included 141 patients, from 11 hospitals across the United Kingdom, who were treated with their first TNFi between January 2010 and December 2011. Mean age at therapy initiation was 50.3±12.1 years; 50% of patients were men, 10% were current smokers, and median disease duration was 5.7 years (interquartile range, 2.0-11.6 years).

Of the total cohort, 76 patients were observed for 4 to 5 years after initiation of their first TNFi (median observation period, 4.5 years [range, 3.4-5.5 years]). The most commonly prescribed first TNFi therapies were adalimumab and etanercept, used in 81 and 57 patients, respectively. A median of 1 different TNFi was used during the observation period (range, 1-5); 11% of patients received 3 or more TNFi therapies during observation.


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Psoriatic arthritis response criteria components were used to evaluate TNFi treatment response. Responses were collected at 12 weeks in 47 patients and at 1 year in 27 patients. The 12-week response rates were 80% and 79% for swollen and tender joint counts, respectively, 79% and 69% for physician and patient global assessments, and 79% for PsARC response.

A total of 79%, 72%, and 65% of patients remained on their first TNFi at 1, 2, and 3 years postinitiation, respectively. After the observation period, 56% of patients were still on their first TNFi, 15% of patients were on their second, 5% were on their third, and 3% were at least on their fourth TNFi; 21% of patients had permanently discontinued TNFi therapy.

Mean therapy duration was 53.6±6.6 months in patients who remained on their first TNFi, and 19.2±16.6 months in those who discontinued their first TNFi. The most common reasons for TNFi discontinuation were lack or loss of efficacy, followed by adverse events.

Disease-modifying antirheumatic drugs (DMARDs) were coprescribed with the first TNFi in 74% of patients. In terms of methotrexate treatment, 86% of patients were already treated with methotrexate at the initiation of their first TNFi, 7% started methotrexate with TNFi, and 7% started methotrexate after TNFi initiation.

Among patients who discontinued TNFi therapy, 23% received no further PsA treatment, 3% received only nonsteroidal anti-inflammatory drugs, 40% received conventional synthetic DMARDs, 3% received only synthetic therapies DMARDs, 10% received only biologic DMARDs, and 20% received conventional synthetic DMARDs plus one or more other treatments.

Study limitations included potential selection bias and variable missing data.

“The recent availability of newer and emerging therapies targeting different inflammatory pathways will enable more individualized treatment for patients with PsA in the future,” the researchers concluded. “Given the changing landscape of PsA management…a future study evaluating the impact of these newer targeted therapies on outcomes in patients with PsA not adequately controlled by conventional DMARDs and for whom TNFi therapy has not been successful is warranted.”

Disclosures: This clinical trial was supported by Novartis Pharmaceuticals UK Ltd. Several study authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.

Reference

Clunie G, McInnes IB, Barkham N, et al. Long-term effectiveness of tumor necrosis factor-αinhibitor treatment for psoriatic arthritis in the UK: a multicenter retrospective study [published online October 17, 2018]. Rheumatol Adv Pract. doi:10.1093/rap/rky042