No abstract

Both non-radiographic spondyloarthritis (nr-SpA) and ankylosing spondylitis (AS) are medical conditions that belong to the axial spondyloarthritis spectrum; these two terms reveal the extent of sacroiliitis assessed by conventional x-ray or MRI. According to the latest classification criteria (ASAS, 2009), clinicians are able to differentiate patients with nr-SpA from AS and to follow their disease progression. The present study aims to compare the two patient categories undergoing biological therapy with an anti-TNF agent and indicate distinct disease features. We included 94 patients in treatment with IFX, ADL, ETA or GOL and monitored clinical, biological and disease activity parameters. The nr-SpA subgroup included a higher percentage of female patients; AS patients presented higher values of the CRP at follow-up visits; there were no significant differences between the two groups regarding the HLA-B27 presence, uveitis history or smoking status. Patients with an inactive disease status had a lower BMI, shorter disease duration and an early initiation of biological therapy, so that we suggest a close and regular monitoring of these two entities.

Objective. The purpose of the present study was to assess the relevance of therapeutic drug monitoring in spondyloarthritis patients, by determining drug serum levels and anti-drug antibodies and estimating cut-off values for three TNF inhibitors. Methods. Over one year, we enrolled 100 patients with SpA, under consequent treatment with adalimumab (ADL), etanercept (ETA) or infliximab (IFX). Demographic, clinical (BASDAI, ASDAS) and laboratory (ESR, CRP) data was collected together with drug serum level and anti-drug antibodies using the ELISA technique. The statistical analysis was performed using the SPSS software, version 20.0 with the aid of Student t-test, Spearman and Pearson tests. Results. Out of the study cohort, 35% were on ADL, 33% on IFX, and 32% under ETA treatment. Undetectable drug levels correlated to the presence of anti-drug antibodies and to disease activity scores. There were no identified anti-ETA antibodies. For this study lot trough levels are estimated between 2 and 4 μg/mL for an ASDAS-CRP under 2.1. Conclusion. Serum drug level measurement and anti-drug antibody detection can be used as a completion to a clinician’s tools in assessing disease activity, leading to an optimal and personalized manner of patient management.

Spondyloarthritis (SpA) patients do not respond uniformly to TNF inhibitor therapy, some of them losing their beneficial evolution and becoming primary or secondary non-responders. Hence, questions have been raised whether this situation is linked to predictive genetic factors, individual characteristics or to disease activity. Studies have incriminated immunogenicity as being responsible for the loss or lack of response. It appears that the development of anti-drug antibodies leads to a decrease in drug levels with further impact on patients’ clinical state. This brief review aims to clarify some of the processes involved in the immunogenic phenomenon for patients with SpA, based on the current published literature.

Background/Objective. Disease activity in spondyloarthritis (SpA) is evaluated through conventional scores such as BASDAI or ASDAS. The aim of this study was to determine disease activity in SpA patients under biological therapy with further assessment on the quality of each activity indicator and their clinical value together with their impact on NSAID intake. Materials and methods. Over nine months (January–August 2015) we enrolled 100 patients with SpA on antiTNF therapy (33% IFX; 35% ADL; 32% ETA). We collected demographic, clinical (BASDAI, ASDAS, PtGA) and laboratory data (ESR, CRP). Frequency of NSAID ingestion expressed as days per week was included in a questionnaire. Considering their biologic treatment, patients were divided into disease activity groups and sample characteristics were correlated and compared. Statistical analysis was performed with SPSS 20.0, using specific tests such as Pearson, Spearman or ANOVA. Results. Patients with active disease, stated by both activity scores had an increased NSAID intake. Out of 86% of patients with a BASDAI under 4, only 82.6% had an ASDAS-CRP lower than 1.3. BASDAI correlated to both ASDAS scores (r = 0.65 and 0.71, P<0.001) and PtGA correlated to both disease activity scales, with a stronger correlation to BASDAI (r = 0.912, P<0.01) than ASDAS (r = 0.67 and 0.71, P<0.01 for both). Conclusion. We proved that disease activity scores have good discriminatory power, with a strong correlation between the subjective BASDAI and PtGA. However, ASDAS-CRP proves to be more rigorous than other variables when targeting high and low disease activity, thus indicating the need of an objective component in assessing these patients.