Therapeutic drug monitoring (TDM) as a tool in the switch from infliximab innovator to biosimilar in rheumatic patients: results of a 12-month observational prospective cohort study.

The objective of this study is to apply therapeutic drug monitoring (TDM) as an objective tool to monitor the switch from infliximab innovator (INX) to infliximab biosimilar (INB) in our diverse rheumatic cohort in daily clinical practice. All rheumatic patients on INX treatment (Remicade®) and ≥18 years were switched to INB (Inflectra®) as part of routine care, but in a controlled setting. Patients were monitored by taking blood samples just before the first infusion of INB (T1), and after the second (T2), fourth (T3), and seventh (T4) infusion of INB. T4 reflects the patients' status after ∼12 months. Infliximab trough levels, antibodies-to-infliximab (ATI), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and validated disease activity scores (if possible) were measured. Our population consisted of 27 patients with seven different rheumatic diseases who had received INX for 143 (58-161) months (median (IQR)). Half of the patients (52%) received concomitant immunosuppressives. We found widely varying infliximab levels, with only 56% within the proposed therapeutic range of 1-5 µg/mL. One patient had very high ATI levels (>880 au/mL), and two had low ATI levels (≤30 au/mL). After switching to INB, seven patients (26%) discontinued the therapy, partially due to subjective reasons. No difference in infliximab levels, CRP levels, and disease activity scores was found between the four time points (p ≥ 0.2460). In conclusion, no pharmacokinetic or clinical differences were found between INX and INB in our diverse rheumatic cohort. TDM is a helpful tool to monitor patients switching from INX to INB.

Assessment of disease activity in patients with rheumatoid arthritis using optical spectral transmission measurements, a non-invasive imaging technique.

OBJECTIVES: In rheumatoid arthritis (RA), treat-to-target strategies require instruments for valid detection of joint inflammation. Therefore, imaging modalities are increasingly used in clinical practice. Optical spectral transmission (OST) measurements are non-invasive and fast and may therefore have benefits over existing imaging modalities. We tested whether OST could measure disease activity validly in patients with RA. METHODS: In 59 patients with RA and 10 patients with arthralgia, OST, joint counts, Disease Activity Score (DAS) 28 and ultrasonography (US) were performed. Additionally, MRI was performed in patients with DAS28<2.6. We developed and validated within the same cohort an algorithm for detection of joint inflammation by OST with US as reference. RESULTS: At the joint level, OST and US performed similarly inproximal interphalangeal-joints (area under the receiver-operating curve (AUC) of 0.79, p<0.0001) andmetacarpophalangeal joints (AUC 0.78, p<0.0001). Performance was less similar in wrists (AUC 0.62, p=0.006). On the patient level, OST correlated moderately with clinical examination (DAS28 r=0.42, p=0.001), and US scores (r=0.64, p<0.0001). Furthermore, in patients with subclinical and low disease activity, there was a correlation between OST and MRI synovitis score (RAMRIS (Rheumatoid Arthritis MRI Scoring) synovitis), r=0.52, p=0.005. CONCLUSIONS: In this pilot study, OST performed moderately in the detection of joint inflammation in patients with RA. Further studies are needed to determine the diagnostic performance in a new cohort of patients with RA.

[The psychometric properties of the Dutch version of the Telephone Interview Cognitive Status (TICS)]. / Telefonisch Interview Cognitieve Status (TICS): psychometrische aspecten.

The Telephone Interview Cognitive Status (TICS) is an instrument to screen for dementia in older persons by telephone. Although the psychometric properties of the TICS have been studied in various countries, the quality of the Dutch version of the TICS was yet unknown. This paper presents the Dutch version of the TICS and reports on its reliability and validity among 51 patients of Maastricht University Hospital, The Netherlands. The Pearson and intra-class correlations for test-retest reliability were 0.93 and 0.92, respectively. The Pearson and intra-class correlations for inter-rater reliability were 0.91 and 0.90, respectively. Sensitivity and specificity were studied in relation to the Mini Mental State Examination (MMSE, cut-off point 23/ 24) and the diagnosis of dementia as assessed according to DSM-IV criteria. When using the TICS cut-off point of 26/27, the coefficients for sensitivity and specificity were at least 0.80. The percentages ROC under the curve were 90% and 93% with the MMSE and the diagnosis dementia as criterion, respectively. We conclude that the Dutch version of the TICS is an acceptable instrument for screening for dementia in older persons, particularly when face-to-face contact is not possible.