PROxIMO: Efficacy of proactive therapeutic drug monitoring and dose adjustment of infliximab based on point of care testing for inflammatory bowel disease

Patients with inflammatory bowel disease (IBD) are prescribed medications used to treat inflammation. Infliximab is an effective intravenous therapy that is used in the treatment of Crohn’s disease and ulcerative colitis. Conventionally, infliximab is given as an infusion every 8 weeks. The dose of infliximab is calculated according to weight and may differ between patients. Despite initially responding to infliximab, some patients will lose response over time, such that the drug no longer continues to work as well as it once did. Studies have demonstrated that patients on a maintenance treatment are more likely to continue to show positive responses to infliximab therapy when the blood level of infliximab, measured just prior to the next scheduled infusion (referred to as a ‘trough level’), is within an optimal range (referred to as ‘therapeutic range’). Infliximab levels are measured from a blood sample. In the past we measured infliximab levels only occasionally. This is partly because the results took time to be processed and were not available on the same day. In this project a blood test will be taken to measure the infliximab level every time patients are due for your infliximab infusion. The test to be used is able to measure the drug level within an hour at the point of care. We will then be able to modify the infliximab dose immediately, in small increments, according to the infliximab level with the aim of ensuring that infliximab levels remain within the ideal therapeutic range. The infliximab blood test and dose modification, if needed, will occur at each visit for the duration of the study (for 12 months, or 6-7 infusions). At each visit, 10mL (about 2 teaspoons) of blood will be taken from your peripheral access line to measure the level of infliximab in your blood along with other blood tests normally conducted when you have your infusion. The information from the blood tests will be used by the researchers to adjust the infliximab dose and to validate the dosing guide. Participants will be asked to provide faecal samples to measure faecal calprotectin, a protein that is secreted in the intestine of patients with inflammation of the gastrointestinal tract (this is a test we currently perform periodically; during this study we will do this test at the second visit and at the end of the study). Participants will be asked to complete a brief survey that assesses quality of life at the beginning and the end of the study, and to answer some short questions about their Crohn’s disease or ulcerative colitis