No benefit of therapeutic drug monitoring in patients starting infliximab therapy
medwireNews: Study results presented at the EULAR 2020 E-Congress suggest that implementing an individualized therapeutic drug monitoring (TDM) strategy at the time of infliximab initiation does not improve remission rates in patients with a range of inflammatory diseases.
“Treatment strategies to optimize the use of TNF [tumor necrosis factor] inhibitors are needed,” because “a significant proportion of patients lack or lose efficacy,” said presenting author Silje Watterdal Syversen (Diakonhjemmet Hospital, Oslo, Norway). She explained that “there is considerable variation in serum drug levels of TNF inhibitors among patients,” with known associations between serum levels and drug effectiveness.
TDM, an individualized treatment strategy based on regular assessment of serum drug levels, “has been proposed as an approach to optimize efficacy, safety and cost-effectiveness of anti-TNF therapy,” she added.
The NOR-DRUM study was an open-label randomized controlled trial involving 398 patients aged an average of approximately 45 years who were allocated to receive infliximab with TDM – involving dose adjustment according to an algorithm aimed at maintaining serum drug levels within a therapeutic range – or to receive standard infliximab administration without TDM.
The most common disease diagnosis in the TDM and control groups was spondyloarthritis (29–30%), followed by ulcerative colitis (20–21%), rheumatoid arthritis (19–21%), Crohn’s disease (14–15%), psoriatic arthritis (10–11%), and psoriasis (5–7%). More than half (55–57%) of the participants were taking concomitant immunosuppressive therapy, while around a fifth (16–21%) were on glucocorticoids.
Syversen reported that rates of remission at week 30 were comparable among patients undergoing TDM and those in the control arm, at 52.9% and 54.1%, respectively. There was also no significant difference in remission rates when the different disease groups were analyzed separately.
Moreover, secondary outcomes including Physician’s Global Assessment and Patient’s Global Assessment scores, C-reactive protein levels, and measures of disease activity, were comparable in the two groups, she said.
Rates of adverse events, serious adverse events, and infection were also similar in the two study arms, but the risk for infusion reactions was significantly lower among patients in the TDM compared with the control group, with rates of 5% and 16%, respectively.
“The NOR-DRUM […] study does not justify implementation of proactive TDM as a general strategy in all patients starting infliximab therapy,” said Syversen.
She concluded that “further research is needed to identify at-risk populations for immunogenicity in which TDM might still be beneficial and to explore the clinical value of a more targeted application of TDM.”
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