Background/Purpose: Limited data are available on the efficacy of anti-TNF agents in non-radiographic axial spondyloarthritis (nr-axSpA). This analysis compares the impact of etanercept (ETN) vs placebo (PBO) on patient-reported outcomes (PROs), after 12 weeks of double-blind treatment in patients (pts) with nr-axSpA who had an insufficient response to NSAIDs.

Methods: Enrolled pts satisfied ASAS criteria for axSpA, had symptom duration of 3 months-5 years and a BASDAI score ≥4 despite current NSAID use. Pts were randomized to ETN 50 mg weekly or PBO with concomitant background NSAIDs. The primary clinical endpoint was ASAS40 at week 12. PROs included BASDAI, BASFI, BAS-G, Work Productivity and Activity Index-Ankylosing Spondylitis (WPAI-AS), Multidimensional Fatigue Inventory (MFI), Nocturnal back pain VAS, total back pain VAS, subject assessment of disease activity (SGA), Short Form (SF-36), Medical Outcomes Study (MOS)-Sleep, Patient Acceptable Symptom State (PASS), Minimal Clinically Important Improvement (MCII), EuroQol (EQ)-5D and Hospital Anxiety and Depression Screening (HADS). ANCOVA models were used with baseline score, treatment, region and SI status as variables. LOCF was used for missing data.

Results: At baseline, MFI general scores (14.7, 15.0 [ETN, PBO]), EQ-5D utility scores (0.52, 0.57), EQ-5D VAS scores (56.5, 56.4) and MOS Sleep Index II scores (45.5, 48.1) were worse than population norms (6.6-8.0¹, 0.86², 82.5³ and 25.8⁴, respectively). By week 12, more pts achieved ASAS40 with ETN50 than PBO (32% vs. 16%, P=0.006).⁵ By week 12 significant improvements favoring ETN50 vs. PBO were seen in stiffness, joint pain, ease of standing from an armless chair, ease of physically demanding and full-day activities, looking over the shoulder, reaching up high, putting on socks and SGA (p<0.05 for all, Table). Mean WPAI presenteeism, SF-36 bodily pain and MOS-sleep quantity favored ETN50 (P<0.05), as did the proportion of pts with MCII (p=0.0458). Non-significant improvements for ETN50 vs. PBO were seen in bending forward from the waist, WPAI, MFI, MOS-Sleep Problems Index I and II, HADS, EQ-5D and SF-36 total scores (P>0.05 for all).

Conclusion: The data show substantial improvements in PRO measures for disease specific and functional domains such as BASDAI, BASFI, BAS-G, and pain, but limited improvement on general PRO measures such as sleep, fatigue and general health. Short disease duration, a short placebo-controlled period, and a wide range of PRO scores at baseline may have influenced relative improvements.