Long-term Etanercept Response for Patients with Radiographic Axial Spondyloarthritis Based on Achievement of Early, Intermediate, or Late Responses During Index Studies

INTRODUCTION

Short-term placebo (PBO)- or active-controlled clinical studies have demonstrated that etanercept (ETN) is effective and well tolerated in patients with radiographic axial spondyloarthritis (r-axSpA) with long-term efficacy and safety continuing for up to 7 years after treatment start. Short-term randomized controlled trials (RCTs) have shown the efficacy of ETN after 12-24 weeks, with statistically significant improvements as early as week 2. This post hoc analysis investigated the timeframe (i.e., temporal responses) in which patients with r-axSpA achieved their first clinical response with ETN and how patients responded over a longer period according to different temporal responses in index studies.

METHODS

Data were analyzed from three phase 3/4 PBO- or sulfasalazine-controlled RCTs of ETN for the treatment of r-axSpA (index studies). Long-term open-label extension (OLE) studies assessed how patients responded over a longer period according to different temporal responses ("Early," "Intermediate," "Late," or "Non-response") in their corresponding index studies.

RESULTS

Within each index study, patient responses differed significantly between ETN and control arms for achievement of Assessment in SpondyloArthritis international Society (ASAS) 20 and other measures of treatment response. In general, the proportion of responders in the OLE studies was high for those with "Early" and "Intermediate" responses as defined in the index studies. Despite patients being considered non-responders in the index studies, a large proportion achieved response on continued treatment in the OLE studies over the longer term, including through 48 weeks.

CONCLUSIONS

Response in the index studies was maintained in the long term, and continued treatment was warranted in a large proportion of patients despite initial non-response. Absence of an early response in index studies did not predict non-response over the long term, and early response to treatment was not always a predictor for later response.

TRIAL REGISTRATION

NCT00421915; NCT00247962; NCT00356356; NCT00421980; NCT00410046.

Prevalence, demographics, and clinical characteristics of Latin American patients with spondyloarthritis

Large epidemiologic and clinical estimates of spondyloarthritis (SpA) in Latin America are not available. In this narrative review, our goal was to descriptively summarize the prevalence and features of SpA in Latin America, based on available small studies. A review of peer-reviewed literature identified 41 relevant publications. Of these, 11 (mostly based on Mexican data) estimated the prevalence of SpA and its subtypes, which varied from 0.28 to 0.9% (SpA), 0.02 to 0.8% (ankylosing spondylitis), 0.2 to 0.9% (axial SpA), and 0.004 to 0.08% (psoriatic arthritis). Demographic and/or clinical characteristics were reported in 31 of the 41 publications, deriving data from 3 multinational studies, as well as individual studies from Argentina, Brazil, Chile, Colombia, Costa Rica, Mexico, Peru, Uruguay, and Venezuela. Data relating to treatment, disease manifestations (articular and extra-articular), and comorbidities were summarized across the countries. Available data suggest that there is a variability in prevalence, manifestations, and comorbidities of SpA across Latin America. Basic epidemiologic and clinical data are required from several countries not currently represented. Data relating to current treatment approaches, patient outcomes, and socioeconomic impact within this large geographic region are also needed.