The NORwegian therapeutic DRUg Monitoring study

project manager

About the project

Biologics, including infliximab, have revolutionized the treatment of a number of chronic inflammatory immunological diseases, but a proportion of patients do not reach the goal of remission and many patients lose efficacy over time. There are large individual differences in blood drug concentrations in patients on standard dose with a large proportion of patients both with no measurable level and with levels well above the assumed therapeutic level. One of the reasons for low levels is the development of antibodies to infliximab. Underdosing in the form of low serum concentrations is related to poorer treatment efficacy while overdosing can increase the risk of side effects and result in unnecessarily high societal costs. Therefore, there was reason to believe that targeting infliximab treatment by serum concentration and drug antibody measurements would put more patients into remission and prevent disease flares during treatment. However, there was a lack of efficacy studies in this area. Therapeutic drug monitoring of infliximab treatment had therefore not been widely implemented either nationally or internationally.

In this study, we wanted to investigate whether targeting infliximab treatment with regular measurements of serum concentration and antibodies would improve disease control in patients starting treatment with infliximab (Part A) and in patients on maintenance therapy (Part B).

We expected that NOR-DRUM could have a major impact on the treatment and follow-up of patients with inflammatory immunological diseases both in the short and long term.

Who can participate?

Adults with ulcerative colitis, Crohn's disease, rheumatoid arthritis, spondyloarthritis, psoriatic arthritis and psoriasis who are starting treatment with infliximab.

Recruitment of participants has been completed.

Project arrangement

The study is now closed.

NOR-DRUM A and NOR-DRUM B are randomized controlled trials. Patients in the intervention group received infliximab based on a treatment strategy based on regular measurements of serum concentration and drug antibody, while the control group received the standard infliximab dose.

In NOR-DRUM A, 400 patients were included. The effectiveness of the intervention was measured by the proportion of patients in remission after 30 weeks (defined by validated disease activity measures for each disease).

In NOR-DRUM B, 500 patients were included and efficacy was measured by the proportion who did not develop disease flare-ups over 52 weeks.

Patients in NOR-DRUM A and B were followed at each infusion, including recording of patient-reported outcome measures, validated disease activity measures for the different diseases and adverse events. Blood samples including biobank and serum concentration and antibodies were taken.


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