Background Treatment recommendations for patients with spondyloarthritis (SpA) who inadequately respond to non-steroidal anti-inflammatory drugs (NSAIDs) and/or traditional disease-modifying antirheumatic drugs (DMARDs) are anti-tumour necrosis factor-alpha therapy (TNFi). There has been no data on the long-term efficacy and safety of TNFi in Thai patients with SpA.
Objectives To evaluate the long-term efficacy and safety of the first TNFi in real-life practice and to identify the risk factors related to drug discontinuation in Thai patients with SpA from the RDPA registry.
Methods Patients who fulfilled the 1984 Modified New York criteria for ankylosing spondylitis (AS), CASPAR criteria or Moll and Wright criteria for psoriatic arthritis (PsA) and the European Spondyloarthropathy Study Group Criteria or Modified Amor criteria for undifferentiated SpA (uSpA), and were prescribed the first TNFi between December 2009 and October 2014 in the RDPA registry were enrolled. Baseline demographic and clinical data were retrieved. A Cox proportional hazard model was used to identify the factors associated with discontinuation. The P-value of <0.05, two-sided was considered statistically significant.
Results Of the 142 patients included, 97 had AS, 41 had PsA, and 4 had uSpA. Most AS patients were male (54.6%) with mean (SD) age of 44.6 (10.6) years, median (P25–P75) baseline BASDAI was 6.5 (5.6, 8.2) [from a 10-cm visual analog scale (VAS)], and median baseline patient global assessment (bPGA) was 7.2 (P25–P75 6.0, 8.0) (from a 10-cm VAS). For PsA patients, most were female (68.3%) with mean age of 52.6 (SD 12.2) years, median baseline BASDAI was 6.6 (P25–P75 4.9, 7.4) in patients with active axial involvement and median baseline number of joint involvement was 13.5 (P25–P75 6, 18.3) joints per patient with active peripheral joint involvement. The Efficacy of the TNFi treatment was good and it was increased over time in AS and PsA patients (figure 1). During the 5-year follow-up, AS, PsA, and uSpA patients had comparable discontinuation rate of their first TNFi treatment [25 (26%) in AS, 14 (34%) in PsA, and 1 (25%) in uSpA; p=0.82]. In univariate analysis, leflunomide use, and bPGA <3 comparing to >6 (from a 10-cm VAS) were associated with the discontinuation of TNFi in AS patients with hazard ratio (HR) (95% CI) of 2.56 (1.13, 5.81) and 8.59 (1.82, 40.65), respectively. For the patients with PsA, only infliximab use was associated with TNFi discontinuation with HR of 4.79 (95% CI 1.33, 17.20) in univariate analysis. The reasons for TNFi discontinuation were good response (38%), serious adverse effects (SAE) (30%), non-adherence (20%), and lack of efficacy (13%). Among SAE, 58% was infectious causes (57% tuberculosis and 43% non-mycobacterium infections). The others were non-infectious causes.
Conclusions During the 5-year follow-up period, patients with SpA responded well to TNFi and the response rate increased over time. Tuberculosis was the most common SAE in this registry therefore surveillance of TB should be done.
Disclosure of Interest P. Chiowchanwisawakit Grant/research support from: The Thai Rheumatism Association, W. Katchamart: None declared, P. Chevaisrakul: None declared, P. Narongroeknawin: None declared, W. Louthrenoo: None declared, M. Osiri: None declared