Up to 5-year retention of abatacept in Belgian patients with moderate-to-severe rheumatoid arthritis: a sub-analysis of the international, observational ACTION study.

Favorable efficacy and safety profiles have been demonstrated for abatacept in patients with rheumatoid arthritis (RA) in randomized controlled trials, but these data require validation during long-term follow-ups in routine clinical practice. This study explored long-term safety and retention rates in RA patients treated with intravenous abatacept in the Belgian cohort of the international AbataCepT In rOutiNe clinical practice (ACTION) study (NCT02109666). This non-interventional, observational, longitudinal study included Belgian patients aged ≥ 18 years with moderate-to-severe RA who started intravenous abatacept treatment as first- or second/further-line biologic therapy in routine clinical practice. Between October 2010 and December 2012, 141 patients were enrolled in this cohort, of whom 135 evaluable patients (6 biologic-naïve; 129 previously exposed to ≥ 1 prior biologic disease modifying anti-rheumatic drugs) were eligible for the descriptive analysis; 131/135 were included in the effectiveness analysis. Mean disease duration was 10.5 years (standard deviation 9.7) before abatacept initiation. RA patients presented with high disease activity and comorbidity rate, having failed multiple previous treatment options. In this cohort, the 5-year abatacept retention rate was 34% (95% confidence interval, 23-45%) per protocol, and 51% (95% confidence interval, 40-61%) when temporary discontinuations of abatacept > 84 days (n = 24) were not considered as treatment discontinuations. After 5 years of abatacept treatment, clinical outcomes were favorable [good/moderate European League Against Rheumatism (EULAR) responses in 91.7% patients]. No new safety signals were detected for abatacept in routine clinical practice. In this difficult-to-treat Belgian RA population, high retention rates, good clinical outcomes and favorable safety profile were observed with abatacept.

A proteomic approach on the effects of TX527, a 1α,25-dihydroxyvitamin D3 analog, in human T lymphocytes.

1α,25-Dihydroxyvitamin D3 (1α,25(OH)2D3), and its analogs (i.e. 14,20-bis-epi-19-nor-23-yne-1α,25(OH)2D3 - TX527) have been shown to prevent autoimmunity and prolong islet graft survival in the non-obese diabetic (NOD) mouse. Their effects are mediated by their action on various immune cell types, such as dendritic cells (DC) and T cells. We have previously reported important direct effects of TX527 on human T cells, on their cytokine/chemokine profiles, T regulatory cell markers, homing characteristics and chemotaxis. In order to fully understand the molecular mechanisms underlying the beneficial properties of TX527 on human T cells, we applied here 2-dimensional difference gel electrophoresis (2-D DIGE) to analyze the global protein alterations induced by TX527 on human synchronized T cells. We detected differential expression of 64 protein spots upon TX527 treatment, of which 65.6% could be successfully identified using tandem mass spectrometry (MALDI-TOF/TOF). The identified proteins function in various processes, such as metabolism and energy pathways, cytoskeleton and protein metabolism. When comparing the proteomics data to our previously performed microarray data on the same set of cells, we found an overlap of 17 different mRNAs/proteins. For some of these (e.g. PSME2, HSPA8), the direction of regulation was not similar, hereby reinforcing the important role of post-transcriptional/translational processes in the functionality of proteins. In addition, although 2-D DIGE offers the possibility of picking up post-translational processes, it lacks the ability to detect molecules with extreme molecular weight (MW) and isoelectrical point (pI) values, or very low abundant/hydrophobic proteins. This study highlights therefore the importance of combining different experimental approaches to obtain a complete picture of the underlying mechanisms and general processes being affected in T cells upon TX527 treatment. These processes lead altogether to the generation of T cells with interesting immunomodulatory features for clinical applications in the treatment of autoimmune diseases or in the prevention of graft rejection. This article is part of a Special Issue entitled '16th Vitamin D Workshop'.

Low doses of anti-CD3, ciclosporin A and the vitamin D analogue, TX527, synergise to delay recurrence of autoimmune diabetes in an islet-transplanted NOD mouse model of diabetes.

AIMS/HYPOTHESIS: Anti-CD3 monoclonal antibodies remain the most promising immune therapy for reversing recent-onset type 1 diabetes. However, current clinical trials have revealed their major drawback, namely the narrow therapeutic window in which low doses are ineffective and higher doses that preserve functional beta cell mass cause side effects. Strategies that sidestep these limitations while preserving or improving anti-CD3's therapeutic efficiency are essential. We hypothesised that combining a potent vitamin D(3) analogue (TX527), ciclosporin A (CsA) and anti-CD3 would act to lower the dose while maintaining or even boosting therapeutic efficacy to counteract autoimmune destruction of transplanted islets. METHODS: This study involved the use of syngeneic islet transplantation, immunofluorescence microscopy, immune phenotyping by flow cytometry, RT-PCR analysis, and in vitro and in vivo suppression assays. RESULTS: Combination therapy with TX527, CsA and anti-CD3 was well tolerated on the basis of weight, bone and calcium variables. Remarkably, combining all three agents at sub-therapeutic doses greatly reduced recurrent autoimmune responses to a grafted islet mass (mean ± SEM: 79.5 ± 18.6 days; p < 0.01), by far exceeding the therapeutic efficacy of monotherapy (24.8 ± 7.3 days for anti-CD3) and dual therapy (25.5 ± 12.4 days for anti-CD3+CsA). Combination therapy surpassed anti-CD3 monotherapy in reducing islet infiltration by effector/memory phenotype CD8(+) T cells, as well as by reducing proinflammatory cytokine responses and increasing the frequency of T regulatory cells that were functional in vitro and in vivo, and acted in a cytotoxic T lymphocyte antigen 4-dependent manner. CONCLUSIONS/INTERPRETATION: Combining the immunomodulatory actions of anti-CD3 mAb with CsA and the vitamin D(3) analogue, TX527, delivers therapeutic efficacy in an islet-transplanted NOD mouse model of diabetes.