{
  "abstract": "Objective Proactive therapeutic drug monitoring (pTDM) intends to optimise tumour necrosis factor (TNF) inhibitor treatment through regular assessment of drug and antidrug antibody levels, enabling individualised dosing. However, health economic evidence for this strategy is limited. This study aims to evaluate the health benefits and costs of pTDM with infliximab compared with standard therapy.Methods Based on the 52-week randomised, controlled, open-label, multicentre Norwegian Drug Monitoring trial (NOR-DRUM) B trial, we estimated the cost-effectiveness of pTDM compared with standard infliximab maintenance therapy in patients with six different immune-mediated inflammatory diseases. For each patient (n=454), we estimated the 12-month healthcare costs, including pharmaceuticals, biochemical tests and other types of resource use. Reported in 2024 Euros, unit costs were based on market prices, diagnosis-related group cost weights and reimbursement schedules. We evaluated health outcomes with quality-adjusted life-years (QALYs), using the EuroQol five-dimension, three-level questionnaire (EQ-5D-3L) and Short Form six-dimension health utility measure (SF-6D). Indicator of cost-effectiveness was the incremental cost-effectiveness ratio, expressed as Euros/QALY, compared with an assumed cost-effectiveness threshold value of €23 755. We assessed sampling uncertainty using the non-parametric bootstrap.Results The mean 1-year cost per patient in the pTDM group was lower than in the standard therapy group, with a difference of €592 (95% CI −1304 to 107), while the QALYs based on EQ-5D-3L were 0.0018 higher (95% CI −0.0126 to 0.0165). Based on the bootstrap results, pTDM has a probability of 95% of being cost-effective. In explorative subgroup analyses, pTDM appeared cost-effective for some, but not all diagnoses.Conclusion pTDM is very likely a cost-effective treatment strategy for patients with immune-mediated inflammatory diseases on infliximab maintenance therapy.Trial registration number NCT03074656.",
  "authors": [
    {
      "affiliations": [
        "Institute of Health and Society, Faculty of Medicine, University of Oslo, Oslo, Norway"
      ],
      "name": "Teresa Holly"
    },
    {
      "affiliations": [
        "Center for Treatment of Rheumatic and Musculoskeletal Diseases (REMEDY), Diakonhjemmet Hospital, Oslo, Norway"
      ],
      "name": "Marthe Kirkesaether Brun"
    },
    {
      "affiliations": [
        "Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway",
        "Department of Gastroenterology, Akershus University Hospital, Lørenskog, Norway"
      ],
      "name": "Kristin Kaasen Jørgensen"
    },
    {
      "affiliations": [
        "Institute of Health and Society, Faculty of Medicine, University of Oslo, Oslo, Norway",
        "Center for Treatment of Rheumatic and Musculoskeletal Diseases (REMEDY), Diakonhjemmet Hospital, Oslo, Norway"
      ],
      "name": "Guro Løvik Goll"
    },
    {
      "affiliations": [
        "Center for Treatment of Rheumatic and Musculoskeletal Diseases (REMEDY), Diakonhjemmet Hospital, Oslo, Norway"
      ],
      "name": "Joseph Sexton"
    },
    {
      "affiliations": [
        "Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway"
      ],
      "name": "Johanna Elin Gehin"
    },
    {
      "affiliations": [
        "Center for Treatment of Rheumatic and Musculoskeletal Diseases (REMEDY), Diakonhjemmet Hospital, Oslo, Norway",
        "Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway"
      ],
      "name": "Tore K Kvien"
    },
    {
      "affiliations": [
        "Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway",
        "Department of Gastroenterology, Akershus University Hospital, Lørenskog, Norway"
      ],
      "name": "Jørgen Jahnsen"
    },
    {
      "affiliations": [
        "Center for Treatment of Rheumatic and Musculoskeletal Diseases (REMEDY), Diakonhjemmet Hospital, Oslo, Norway",
        "Department of Public Health and Sport Sciences, Faculty of Social and Health Sciences, University of Inland Norway, Elverum, Norway"
      ],
      "name": "Sella A Provan"
    },
    {
      "affiliations": [
        "Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway"
      ],
      "name": "Nils Bolstad"
    },
    {
      "affiliations": [
        "Institute of Health and Society, Faculty of Medicine, University of Oslo, Oslo, Norway",
        "Department of Health Services Research, Norwegian Institute of Public Health, Oslo, Norway"
      ],
      "name": "Eline Aas"
    },
    {
      "affiliations": [
        "Center for Treatment of Rheumatic and Musculoskeletal Diseases (REMEDY), Diakonhjemmet Hospital, Oslo, Norway",
        "Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway"
      ],
      "name": "Espen A Haavardsholm"
    },
    {
      "affiliations": [
        "Institute of Health and Society, Faculty of Medicine, University of Oslo, Oslo, Norway",
        "Research Unit of General Practice, University of Southern Denmark, Odense, Denmark"
      ],
      "name": "Ivar S Kristiansen"
    },
    {
      "affiliations": [
        "Institute of Health and Society, Faculty of Medicine, University of Oslo, Oslo, Norway",
        "Center for Treatment of Rheumatic and Musculoskeletal Diseases (REMEDY), Diakonhjemmet Hospital, Oslo, Norway"
      ],
      "name": "Silje Watterdal Syversen"
    },
    {
      "affiliations": [
        "Center for Treatment of Rheumatic and Musculoskeletal Diseases (REMEDY), Diakonhjemmet Hospital, Oslo, Norway",
        "Department of Health Services Research, Norwegian Institute of Public Health, Oslo, Norway"
      ],
      "name": "Gunhild Hagen"
    }
  ],
  "title": "Cost-effectiveness of proactive therapeutic drug monitoring of maintenance infliximab treatment in patients with immune-mediated inflammatory diseases: results from a randomised controlled trial",
  "uid": "ec31be78-4419-5fca-a45b-3795fcd0ca5b"
}