Patients with PsA respond better to biologic DMARDs vs. those with RA at 12 years
A greater percentage of patients with psoriatic arthritis achieve remission with biologic therapy than those with rheumatoid arthritis, at both 1- and 12-year follow-up, according to data published in Arthritis Research & Therapy.
“Numerous RCTs examine [biologic] DMARDs in [inflammatory arthritis],” Kieran Murray, MD, of St. Vincent’s University Hospital, in Dublin, and colleagues wrote. “However, these may not be generalizable to routine clinical practice due to strict inclusion criteria, short duration and relatively small sample sizes. Registries can provide more real-world data. Again, these may only follow patients for a limited time and, in comparison to RA, there remains a paucity of data on biologic use in PsA. Given the lack of RCTs comparing TNFi, observational studies are required.”
“A meta-analysis found rates of 1-year biologic persistence, defined as a continuation of a therapy, in RA varied from 32.0 to 90.9%,” they added. “Less is known about a long-term biologic persistence in PsA. Among German patients on subcutaneous biologics, a higher proportion of PsA patients (57.9%) remained on therapy 12months compared to RA (51.9%). In the U.S. Corrona registry, 36.1% of PsA patients continued on their medication at 48months. Medication continuation studies are often based on administrative data, lacking important clinical and laboratory parameters.”
To investigate the predictors of remission and biologic therapy persistence among patients with RA or PsA after 12 years — specifically regarding adalimumab (Humira, AbbVie) and etanercept (Enbrel, Amgen) — Murray and colleagues analyzed individuals from a prospective database recruited from a biologic outpatient clinic in 2000. For their own study, the researchers reviewed the outcomes of initiating therapy for 403 participants — 274 with RA and 129 with PsA — at 1 and 12 years.
Murray and colleagues collected data on demographics, medications, morning stiffness, patient global health score, tender and swollen joint counts, antibody status, C-reactive protein (CRP) and Health Assessment Questionnaire (HAQ) scores. The researchers used univariate and multivariate analyses to examine predictors of biologic persistence and remission — the latter based on the EULAR definition of a Disease Activity Score-CRP of less than 2.6.
According to the researchers, patients with PsA were more likely to be male, work full-time and have a college degree. In addition, those with PsA demonstrated higher remission rates than those with RA at 1 year — 60.3% compared with 34.5% (P<.001) — and 12years — 91.3% compared with 60.6% (P<.001). This difference persisted when patients were matched for baseline disease activity (P<.001).
Meanwhile, biologic persistence rates were high for both RA and PsA at 1 year — 49.6% compared with 58.9% — and 12years — 38.2% compared with 52.3%.
Among patients with PsA, those who started etanercept demonstrated lower CRP at 12years, compared with patients with RA (P=.041). The multivariate analysis found that 1-year persistence (OR = 4.28; 95% CI, 1.28-14.38) and 1-year low-disease activity (OR = 3.9; 95% CI, 1.05-14.53) predicted 12-year persistence. Additionally, persistence with an initial biologic at 12 years (OR 4.98; 95% CI, 1.83-13.56) and male gender (OR = 4.48; 95% CI, 1.25-16.01) predicted remission at 12 years.
“A greater percentage of PsA patients achieves remission on bDMARD therapy compared to RA patients,” Murray and colleagues wrote. “Both achieve higher frequencies of remission compared to previous analyses of csDMARD therapy alone.”
“PsA patients had significantly higher levels of employment and education,” they added. “One-year bDMARD persistence and low-disease activity at 1 year were predictive of a 12-year persistence. Male gender and 12-year persistence predicted a 12-year remission. In a comparison of adalimumab and etanercept, outcomes were very well matched with no differences in remission or continuation rate in either RA or PsA.”