Among patients with axial spondyloarthritis (axSpA), the first-time initiation of tumor necrosis factor inhibitor (TNFi) therapy can lead to the achievement of inactive disease status after 6 months, according to study results published in the Annals of the Rheumatic Diseases.
Researchers examined drug retention and response rates in a large European cohort of patients with axSpA who were initiating their first TNFi therapy; data were prospectively collected and pooled from 12 registries.
Primary study outcomes included the 12-month overall TNFi drug retention rate. Secondary outcomes were overall 6- and 24-month retention rates and overall percentage of patients with axSpA achieving Ankylosing Spondylitis Disease Activity Score (ASDAS) inactive disease (<1.3), Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) <40 mm, and Assessment of SpondyloArthritis International Society (ASAS) 20/40 response rate at 6, 12, and 24 months.
The total study cohort included 24,195 patients with axSpA. Three subcohorts were identified: ASAS cohort (n=6097), modified New York Criteria for Ankylosing Spondylitis (NY) cohort (n=2935), and nonradiographic axSpA (nr-axSpA) cohort (n=1178). The most common treatments included adalimumab (29%), infliximab (28%), and etanercept (25%); 14% of patients were treated with golimumab, 5% were treated with certolizumab, and 31% of patients were treated with conventional synthetic disease-modifying antirheumatic drugs. Median time since diagnosis was 2 years (interquartile range [IQR], 1-9 years).
In the total cohort, the 12-month TNFi retention rate was 80%. For the ASAS, NY, and nr-axSpA subcohorts, 12-month retention rates were 81% (range, 80%-82%), 83% (range, 82%-85%), and 73% (range, 70%-76%), respectively. The overall retention rates for all patients were 88% (range, 87%-88%) at 6 months and 73% (range, 72%-73%) at 24 months. Within individual registries, the 12-month retention rate “differed significantly,” ranging from 71% to 94% (P <.001).
At 6, 12, and 24 months, ASDAS inactive disease was achieved in 33%, 35%, and 38% of patients, respectively. BASDAI <40 proportions were 72%, 75%, and 77%, with ASAS 20/40 response rates achieved in 64%/49% at 6 months, 67%/53% at 12 months, and 68%/54% at 24 months. Within the subcohorts, ASDAS inactive disease responses rates at 6 months were 30%, in the ASAS, 25% in the NY, and 26% in the nr-axSpA cohorts. Individual registry 6-month response rates ranged from 29% to 53%, and 61% to 86% for ASDAS inactive disease and BASDAI <40 measurements, respectively (P <.001).
In total, 23% (n=5673) of patients withdrew from the treatment during 24 months of follow-up. Of these, 3654 patients withdrew because of lack of efficacy, and 2019 withdrew because of adverse events. Median time to withdrawal was 7 months (IQR, 4-13 months).
Study limitations included selection bias according to data availability and a potential overestimation of drug retention rates.
“Approximately a third of patients were in ASDAS inactive disease state after 6 months, and 80% were still receiving the same TNFi after 1 year,” the researchers concluded.
Disclosure: This clinical trial was supported by Novartis Pharma AG. Please see the original reference for a full list of authors’ disclosures.
Ørnbjerg LM, Brahe CH, Askling J, et al. Treatment response and drug retention rates in 24 195 biologic-naïve patients with axial spondyloarthritis initiating TNFi treatment: routine care data from 12 registries in the EuroSpA collaboration [published online August 20, 2019]. Ann Rheum Dis. doi:10.1136/anrheumdis-2019-215427