SummaryVarious complement-mediated renal disorders are treated currently with the complement inhibitor eculizumab. By blocking the cleavage of C5, this monoclonal antibody prevents cell damage caused by complement-mediated inflammation. We included 23 patients with atypical haemolytic uraemic syndrome (aHUS, n 5 12), C3 glomerulopathies (C3G, n 5 9) and acute antibody-mediated renal graft rejection (AMR, n 5 2), treated with eculizumab in 12 hospitals in Germany. We explored the course of complement activation biomarkers and the benefit of therapeutic drug monitoring of eculizumab. Complement activation was assessed by analysing the haemolytic complement function of the classical (CH50) and the alternative pathway (APH50), C3 and the activation products C3d, C5a and sC5b-9 prior to, 3 and 6 months after eculizumab treatment. Eculizumab concentrations were determined by a newly established specific enzyme-linked immunosorbent assay (ELISA). Serum eculizumab concentrations up to 1082 lg/ml point to drug accumulation, especially in paediatric patients. Loss of the therapeutic antibody via urine with concentrations up to 56 lg/ml correlated with proteinuria. In aHUS patients, effective complement inhibition was demonstrated by significant reductions of CH50, APH50, C3d and sC5b-9 levels, whereas C5a levels were only reduced significantly after 6 months' treatment. C3G patients presented increased C3d and consistently low C3 levels, reflecting ongoing complement activation and consumption at the C3 level, despite eculizumab treatment. A comprehensive complement analysis together with drug monitoring is required to distinguish mode of complement activation and efficacy of eculizumab treatment in distinct renal disorders. Accumulation of the anti-C5 antibody points to the need for a patient-orientated tailored therapy.
BACKGROUND
Ustekinumab was approved in Europe for the treatment of adults with moderate to severe Crohn's disease (CD) in 2016, and there is an urgent need for data on its everyday use.
AIM
To obtain data on the daily use of ustekinumab.
METHODS
This is a retrospective monocentric study. Patients with moderate to severe CD who began ustekinumab therapy at the inflammatory bowel diseases outpatient clinic of the Heidelberg University Hospital between December 2016 and March 2018 were selected based on electronic patient files. The primary study endpoint was combined steroid-free clinical remission or steroid-free clinical response at 24 ± 6 wk of ustekinumab therapy. Secondary study endpoints were: achievement of mucosal healing, sonographic and magnetic resonance imaging response, biochemical response, the need for intestinal surgery within 24 ± 6 wk after treatment initiation, the occurrence of adverse events, treatment discontinuation due to nonresponse or adverse events, improvement of extraintestinal manifestations, clinical response at 48 ± 6 wk of therapy, and association of response with nucleotid oligodimerisation domain 2 mutations.
RESULTS
Fifty-seven patients with CD (5.3% anti-tumour necrosis factor α naïve, 63.2% having undergone at least one intestinal surgery) were included in the study. Twenty patients (35.1%) achieved steroid-free clinical remission, 6 (10.5%) steroid-free clinical response and 31 (54.4%) were non-responders. Treatment discontinuation due to adverse events occurred in two patients (3.5%). Male sex, the presence of extraintestinal manifestations and the use of steroids at baseline were predictors of nonresponse to ustekinumab therapy.
CONCLUSION
In a “real-world” treatment-refractory cohort of patients with CD, ustekinumab appeared efficacious and safe.
Complement activation at the acute phase of EHEC-HUS, indicated by increased levels of sC5b-9, predicts a poor outcome. Complement alterations appear to be more frequent in patients with EHEC-HUS than previously thought and are suspected to have a role in the severity of the disease.
Not every patient with aHUS and uncontrolled complement activation shows optimal therapeutic response to eculizumab with the recommended or even increased dosing regimen. Reliable outcome measures to determine the efficacy of treatment have to be defined.
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