Patients with psoriatic arthritis (PsA) meeting the inclusion criteria for randomized controlled trials (RCTs) associated with their chosen tumor necrosis factor inhibitor (TNFi) had similar disease activity scores as patients who were not included in study populations, according to research results published in RMD Open.
Researchers conducted a retrospective cohort study to determine if patients with PsA who did not fulfill the inclusion criteria for RCT associated with their TNFi still experienced treatment benefits and comparable drug survival rates compared with those patients who fulfilled the inclusion criteria.
The current study included all ICEBIO patients with PsA who were treated with adalimumab, etanercept, golimumab, or infliximab as their first biologic treatment between January 2000 and February 2016. The ICEBIO database is a registration of all patients in Iceland treated with biologic disease-modifying antirheumatic drugs (bDMARDs), based on the Danish Registry for biological therapies in rheumatology.
The study cohort (n=1058) included 329 patients with PsA. Of these patients, 274 initiated a TNFi as their first-ever treatment; using available data, 226 patients were eligible per the inclusion criteria for RCTs for adalimumab, etanercept, golimumab, or infliximab.
Among the 226 patients that comprised the study population, 74 met the inclusion criteria, and 152 did not. The most commonly used TNFi was etanercept in the inclusion group and infliximab in the exclusion group (38% and 63%, respectively).
Both groups were demographically similar at baseline; however, the inclusion group vs the exclusion group had a higher mean swollen joint count (5.5±3.3 vs 3.8±3.6; P =.003) and a higher Disease Activity Score (DAS) in the 28-joints C-reactive protein score (CRP; 4.6±0.8 vs 4.2±0.9; P =.01).
At 6 and 18 months, no difference was recorded in both patient-reported outcomes and disease activity indicators, although compared with the inclusion group, the exclusion group had a higher mean CRP at 18 months (3.1±2.5 vs 6.1±9.6). No difference was noted between the groups at baseline.
In terms of visual analog scores for pain, fatigue, patient or physician global assessment scores, no difference was noted between the groups. Health Assessment Questionnaire responses were statistically significantly better in the inclusion vs the exclusion group (-0.8±0.7 vs -0.3±0.6; P =.008) at 6 months. The difference was not statistically significant at 18 months.
There was no statistically significant difference between the inclusion and exclusion group in the American College of Rheumatology (ACR)20 response rate at 6 or 18 months (77% vs 60%; P =.207 and 69% vs 59%; P =.545, respectively). Investigators noted a numerical, statistically insignificant, difference in the proportion of patients achieving ACR50 at 6 months; this difference was statistically significant by 18 months.
In addition, both groups had similar 2-year drug survival rates. A total of 46% of patients (n=74) in the inclusion group and 44% (n=152) in the exclusion group discontinued therapy prior to the end of the second year. No statistically significant differences were noted between the groups for the 4 types of TNFi.
Study limitations included the small size of the study population and the lack of 66/68 joint counts recorded within the cohort.
“Treatment outcomes for bDMARD treatment in PsA from RCTs may likely be applied to daily clinical practice, irrespective of whether patients would have fulfilled RCT criteria or not,” the researchers concluded.
Disclosure: Several study authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.
Palsson O, Love TJ, Gunnarsdottir AI, et al. Patients with psoriatic arthritis who are not eligible for randomised controlled trials for TNF inhibitors have treatment response and drug survival similar to those who are eligible [published online July 16, 2019]. RMD Open. doi:10.1136/rmdopen-2019-000984