Practical Aspects of Biological Throught Levels and Antidrug Antibodies in Rheumatoid Arthritis and Spondyloarthritis

Performance of a New Rapid Point-of-Care Test for Infliximab Levels in Patients with Inflammatory Bowel Disease: A Comparison to ELISA

BACKGROUND

Therapeutic drug monitoring of infliximab levels in patients with inflammatory bowel disease (IBD) optimizes patients' treatment. The reference technique is based on enzyme-linked immunosorbent assay (ELISA) although point of care (POC) assays are being developed.

AIMS

To assess the performance of a new rapid immunochromatographic POC assay (Promonitor Quick IFX) compared with ELISA technique to measure infliximab levels in patients with IBD.

METHODS

A prospective, observational, unicentric study was performed on capillary blood samples from patients with IBD before infliximab infusion (trough levels). Infliximab levels and anti-infliximab antibodies were measured using the ELISA technique (Promonitor IFX) and the POC assay. Correlation between both techniques was assessed by Pearson's coefficient. Quantitative differences were evaluated by Bland-Altman analysis. Samples were stratified according to infliximab therapeutic ranges (< 3 μg/mL, 3-8 μg/mL, and > 8 μg/mL).

RESULTS

A total of 135 experimental samples were assessed. Infliximab levels showed a high correlation between POC and ELISA tests (r = 0.84, P < 0.001). The mean difference between tests was 1.46 μg/mL (P < 0.001), being minimal for concentrations < 8 μg/mL. POC and ELISA assays showed an overall concordance of 87.4%. Most samples were in the same therapeutic range, which lead to equivalent therapeutic decisions. POC and ELISA assays detected the presence of anti-infliximab antibodies in 2.2% and 3.7% of the samples, respectively.

CONCLUSIONS

POC assay results in blood samples from patients with IBD were comparable to those obtained with the reference ELISA technique. The POC assay could be considered for routine testing based on its ease of use and rapidity.

Refractory multisystemic sarcoidosis, a diagnosis and treatment challenge: a case report

BACKGROUND

Sarcoidosis is a multisystemic granulomatous disease of unknown origin. It is characterized by abnormal activation of lymphocytes and macrophages with the formation of granulomas. Most cases have asymptomatic pulmonary involvement. In case of symptoms, they have an excellent response to glucocorticoid therapy. We present a case of sarcoidosis with multi-organ involvement, refractory to multiple treatments including biological. Partial remission was achieved in it.

CASE PRESENTATION

We report an interesting case of a 38-years-old Spanish woman treated by Heerfordt's syndrome (uveitis, parotiditis, fever and facial palsy) plus pulmonary hiliar adenopathy. A sarcoidosis diagnosis was confirmed by lung biopsy. She was initially treated with an 8 weeks course of medium dose oral glucocorticoids and tapered over 8 weeks with improvement. After the suspension of glucocorticoids a relapse occurs with severe ocular involvement and suspicion of neurological involvement. The patient received multiple lines of treatment with poor response. Finally, after the combination of cyclophosphamide with infliximab, the uveitis resolved, improving the neurological symptoms.

CONCLUSIONS

Sarcoidosis is a benign disease in most cases. In a small percentage of cases behaves aggressively, requiring early diagnosis and immunosuppressive treatment to avoid sequelae. An adequate immunosuppressive therapy based on Anti TNF drugs should be started to minimize damage and improve the quality of life.The choice of treatment depends on the type and severity of the disease.

Anti-TNFα drug levels in patients with rheumatoid arthritis and spondyloarthritis

BACKGROUND AND OBJECTIVES

Knowledge of the levels of anti-TNFa drugs can modify treatment in patients with rheumatoid arthritis (RA) and spondyloarthritis (SpA).

OBJECTIVES

To compare the levels of anti-TNFa in patients with RA vs SpA, in different clinical situations.

MATERIALS AND METHODS

A retrospective, observational study was conducted. Levels of anti-TNFa and the presence of anti-drug antibodies were measured in consecutively selected patients, using the ELISA technique.

RESULTS

Fifty-three, 73 and 78 patients treated with infliximab, adalimumab and etanercept were studied, respectively. The median drug levels in patients using standard doses were infliximab 2.2 µg/mL (1.4-5.2), adalimumab 4.9 µg/mL (0.8-8.9) and etanercept 3.1 µg/mL (2.3-4.4). There were no differences in drug levels according to disease activity but we found differences in etanercept and infliximab levels according to DMARD use.

CONCLUSIONS

Levels of anti-TNFa drugs will change with DMARD treatment.

Anti-TNFα Drug Levels in Patients with Rheumatoid Arthritis and Spondyloarthritis

BACKGROUND AND OBJECTIVES

Knowledge of the levels of anti-TNFα drugs can modify treatment in patients with rheumatoid arthritis (RA) and spondyloarthritis (SpA).

OBJECTIVES

To compare the levels of anti-TNFα in patients with RA vs SpA, in different clinical situations.

MATERIALS AND METHODS

A retrospective, observational study was conducted. Levels of anti-TNFα and the presence of anti-drug antibodies were measured in consecutively selected patients, using the ELISA technique.

RESULTS

Fifty-three, 73 and 78 patients treated with infliximab, adalimumab and etanercept were studied, respectively. The median drug levels in patients using standard doses were infliximab 2.2μg/ml (1.4-5.2), adalimumab 4.9μg/ml (0.8-8.9) and etanercept 3.1μg/ml (2.3-4.4). There were no differences in drug levels according to disease activity but we found differences in etanercept and infliximab levels according to DMARD use.

CONCLUSIONS

Levels of anti-TNFα drugs will change with DMARD treatment.

An update on serum biomarkers to assess axial spondyloarthritis and to guide treatment decision

Axial spondyloarthritis (axSpA) is a group of debilitating, chronic, rheumatic conditions characterized by inflammation and new bone formation, mainly involving the spine and the sacroiliac joints. The lack of biomarkers in axSpA is well known. Despite significant treatment advances in recent years thanks to the introduction of drugs with a new mode of action, such as new biologic and targeted synthetic disease-modifying antirheumatic drugs, no relevant improvement in the identification of disease biomarkers has been achieved. Common parameters, such as erythrocyte sedimentation rate and C-reactive protein, which are routinely used to measure systemic inflammation, are the sole markers available to date and are not adequate to assess disease activity in all patients. The aim of this study is to review the most promising serum biomarkers that may help treatment decision in axSpA via a proper assessment of disease activity and identification of negative prognostic factors.