Therapeutic Drug Monitoring Does Not Improve Remission Rates in Patients Starting Infliximab Therapy

June 10, 2020

By Eric Ramos

CHICAGO -- June 9, 2020 -- Therapeutic drug monitoring in patients with rheumatic diseases who are starting treatment with infliximab does not appear to be superior to standard treatment in order to achieve remission, according to a study presented at the 2020 Virtual Meeting of the European League Against Rheumatism (EULAR).

“A lack or loss of response to TNF [tumour necrosis factor] inhibitors has been associated with low serum drug levels and formation of anti-drug antibodies,” reported Silje W. Syversen, MD, Diakonhjemmet Hospital, Oslo, Norway. “Therapeutic drug monitoring has been suggested to optimise efficacy of TNF inhibitors. The Norwegian Drug Monitoring Trial Part A is the first randomised trial to address effectiveness of therapeutic drug monitoring in the induction period of infliximab inhibitor treatment, and the first trial to address therapeutic drug monitoring in rheumatic diseases.”

The study randomised adult patients with rheumatoid arthritis (n = 80), psoriatic arthritis (n = 42), spondyloarthritis (n = 117), ulcerative colitis (n = 80), Crohn’s disease (n = 57), and psoriasis (n = 22) to begin treatment with infliximab with or without therapeutic drug monitoring. In the drug monitoring group, infliximab dose and interval were adjusted according to trough levels to reach the therapeutic range.

Remission at week 30 -- the primary endpoint -- was reached by 100 (53%) patients in the therapeutic drug monitoring arm and by 106 (54%) patients in the standard therapy arm. No differences in remission rates were observed according to disease.

Of the patients in the drug monitoring arm, 20 (10%) developed significant levels of anti-drug antibodies, compared with 30 (15%) patients in the standard therapy arm.

Adverse events were similar in both groups; however, infusion reactions were less frequent in the therapeutic drug monitoring arm (2.5% vs 8.0%).

“In this study, therapeutic drug monitoring was not superior to standard treatment in order to achieve remission,” said Dr. Syversen. “Although improved safety is indicated by a reduction in infusion reactions, implementation of therapeutic drug monitoring as a general strategy in the induction period of infliximab is not supported by [the results of this study].”

[Presentation title: Therapeutic Drug Monitoring Compared to Standard Treatment of Patients Starting Infliximab Therapy: Results From a Multicentre Randomised Trial of 400 Patients. Abstract OP0017]