Background: The chance of a good response in RA is attenuated in previous anti-TNF users who start new anti-TNF therapy compared to biologic naïve patients. In active RA, those with previous anti-TNF exposure compared to anti-TNF naïve may have different baseline disease activity and patient perceptions when starting a new anti-TNF treatment that could explain the observed response differences.
Material/Methods: The aim of this study was a post hoc analysis of baseline characteristics of patients enrolled in the Optimization of Adalimumab study that was a treat to target vs. routine care study in patients initiating adalimumab. As per the protocol, a maximum of 20% anti-TNF experienced patients were enrolled in the 300 patient trial. Twelve (4.0%) were excluded who previously used other biologics. Baseline characteristics including age, gender, tender and swollen joint counts, disease activity (DAS28), function (HAQ-DI), patient global assessment, patient satisfaction with current treatment, and inflammatory markers (CRP, ESR), were compared between previously anti-TNF experienced [etanercept or infliximab (EXP)], and anti-TNF naïve patients (NAÏVE).
Results: The mean (SD) age was 54.8 (13.3) years; 81.0% were female, and 237 (79.0%) were anti-TNF naïve while 51 (17.0%) patients were anti-TNF experienced (29 with etanercept, 16 with infliximab, and 6 for both). The mean (SD) baseline in EXP versus NAÏVE groups respectively was: CRP=21.7(32.9) vs. 17.5(20.7); ESR=28.7(22.5) vs. 29.8(20.4); SJC=10.5(6.0) vs. 10.7(5.6); TJC=12.8(7.1) vs. 12.3(7.3); and DAS28=6.0(1.2) vs. 5.8(1.1). None of the between-group differences were statistically significant, however, the HAQ-DI in EXP was 1.7(0.6) compared to 1.5(0.7) for the NAÏVE (P=0.021). Additionally, EXP patients had a higher patient global score [71.3(26.1) vs. 61.9(26.2), P=0.021].
Conclusions: Although anti-TNF naïve and experienced patients who initiated adalimumab were similar, with respect to several baseline characteristics, significant differences in subjective measures were observed, which may indicate more severe patient measures (function and global disease activity) in anti-TNF experienced patients.

Keywords: Perception, C-Reactive Protein - metabolism, Blood Sedimentation, Arthritis, Rheumatoid - pathology, Antirheumatic Agents - therapeutic use, Antibodies, Monoclonal, Humanized - therapeutic use, Tumor Necrosis Factor-alpha - metabolism