Evaluating a rapid on-site test for the monitoring of infliximab trough levels- a pilot study

Anti-TNF antibodies are considered to be potent treatment modality for
inflammatory bowel disease patients (Terdiman et al., 2013). Infliximab was the
first anti-TNF available for the treatment of IBD patients and has been
reported to be efficacious for both the induction as the maintenance of
remission in patients with Crohn*s disease as well as patient with ulcerative
colitis (Terdiman et al., 2013).
Up to 50% of patients will develop loss of response to infliximab (Ben-Horin et
al., 2014). In a given patient, a number of strategies exist to try and
overcome this loss of response such as escalation of the dose or switching to
another anti-TNF drug. However, the preferred route is via measuring of trough
levels and antibodies to infliximab as this enables to identify patients that
may benefit from dose escalation and patients who fail in spite of having
therapeutic drug trough levels (Ben-Horin et al., 2014).
Studies on therapeutic drug monitoring, which encompasses measurement of
infliximab through levels (TL) and measurement of antibodies to infliximab
(ATI), have shown that patients in remission may have widely differing TLs.
Patients with a low TL may benefit from optimizing dosage in order to prolong
the remission period. In patients with a supra-therapeutic TL may reduce the
change for side effects when the dose is reduced (or the interval between
visits increased). An additional benefit in this scenario would be that, as
infliximab is an expensive drug, reducing the dose might yield important
savings.
However, currently infliximab TL measurements are beholden to specialized
laboratories and the sending and processing of blood samples precludes on site
measurement of TLs. When it would be feasible to measure the TL just before the
infusion starts, it may be possible to reduce (or increase) the planned amount
of infliximab.
Recently, our group has performed a proof of principle study (Corstjens et al.,
2013) on a rapid lateral flow-based assay format that could enable on-site
monitoring of infliximab TLs. In that study, an excellent correlation was
observed between the results of the lateral flow-assay and the standard ELISA
infliximab assay. However, blood was taken by venapunction and measurements
were performed in serum. Furthermore, the current lateral flow reader uses
phosphorus as this enables measurement of lower concentrations. However, the
use of a gold-based reader would enable a more rapid analysis and, as these
readers are available of the shelve, would reduce assay costs.

To determine the correlation between concetrations of inflextra/ infliximab as
measured using finger prick blood and lateral-flow assay and using venous blood
and the standard sanquin ELISA.

prospective multicentre observational pilot study

minor risk, as the only extra action is a fingerprick