There is one clinical trial.
Inflammatory bowel disease (IBD) is a common disease in Canada, leading to significant morbidity as a result of remitting and relapsing intestinal inflammation. Currently, tumor necrosis factor (TNF) antagonists such as infliximab, make up 30% of the biologic agents available to individuals with IBD. There is a high risk of losing response or having a hypersensitivity reaction to infliximab, necessitating treatment discontinuation. This is due, in part, to the formation of anti-drug antibodies (ADAs). ADA formation can result in loss of response to therapy which may eliminate an intestine-saving therapy and increases their risk of progressing to surgical resection. There are few tools clinicians can implement to minimize the risk of ADA formation. The current approach is to add a second drug (known as combination therapy), specifically an immunomodulator (methotrexate or azathioprine), exposing the patient to additional medication-related risks, intensive monitoring with bi-weekly blood work and potential side effects including infection and malignancy. Preliminary data from our group as well as others suggests that individuals who carry a variant in the class 2 human leukocyte antigen (HLA) gene (HLADQA1*05A>G, rs2097432) are more likely to form ADAs to infliximab. Pre-emptive screening for this variant may allow clinicians to more selectively use combination therapy, recommending it only in IBD patients at high risk of developing ADAs to infliximab. Additionally, this may result in fewer drug-associated adverse events. With this project, we aim to explore the value of prospective HLADQA1*05 screening (pharmacogenomic screening) in IBD patients being considered for treatment with infliximab and using the result to guide the application of combination therapy compared to IBD patients treated with infliximab (with or without a second agent) as per current practice. We will assess the incidence of infliximab ADA formation, as well as the incidence of infliximab loss of response, treatment discontinuation, and adverse drug events. Additionally, we will assess the time to each of these events.
Preliminary data from our group as well as others suggests that individuals who carry a variant in the class 2 human leukocyte antigen (HLA) gene (HLADQA1*05A>G, rs2097432) are more likely to form ADAs to infliximab.
Recently, in an peer-reviewed dataset, a group demonstrated that variation in the class 2 human leukocyte antigen (HLA) gene region (HLADQA1*05A>G, rs2097432) is linked to an increased risk of ADA formation against infliximab and to a lesser extent, its sister TNF-antagonist, adalimumab18.
In a separate, retrospective study, we have confirmed that variation in HLADQA1*05A>G (rs2097432) is independently-associated with a significantly higher incidence of and faster progression to infliximab ADA formation.
Description: Evaluate the impact of pharmacogenomic screening and the administration of targeted-combination infliximab therapy to high risk (variant-carrying) individuals compared to an unscreened IBD population receiving standard of care (where combination therapy is administered at the discretion of the physician) on the incidence of infliximab ADA formation. Infliximab ADA formation is defined as any detectable amount of ADA in the absence of detectable serum infliximab (measured by enzyme-linked immunosorbent assay, ELISA).
Measure: incidence of infliximab anti-drug antibodies Time: 1 yearDescription: defined as a relapse in clinical symptoms after week 14 of infliximab dosing, with an increase in the Harvey Bradshaw index (HBI) ≥ 3 points or the partial Mayo score ≥ 3 points, following a response to infliximab induction therapy where a 3-point reduction was seen in the HBI or partial Mayo score
Measure: incidence of infliximab loss of response Time: 1 yearDescription: when stopped by treating physician
Measure: incidence of infliximab discontinuation Time: 1 yearDescription: defined as any injury presumed secondary to infliximab exposure as deemed by the treating gastroenterologist. This is including but not limited to: infection, immediate infusion reaction, delayed infusion reaction, psoriaform rash
Measure: incidence of infliximab-related adverse drug events Time: 1 yearDescription: defined as any injury presumed secondary to azathioprine or methotrexate exposure as decided by the treating gastroenterologist. This is including, but not limited to: infection, nausea and dyspepsia, myelotoxicity, hepatoxicity, pancreatitis
Measure: incidence of immunomodulator-related adverse drug events Time: 1 yearDescription: defined in outcome 4 and 5
Measure: incidence of combination therapy (infliximab and one of methotrexate or azathioprine) -related adverse drug events Time: 1 yearDescription: measured from the time of treatment initiation to the time of antibody formation
Measure: time to infliximab anti-drug antibody formation Time: 1 yearDescription: measured from the time of treatment initiation to the time of infliximab loss of response defined as a relapse in clinical symptoms after week 14 of infliximab dosing, with an increase in the Harvey Bradshaw index (HBI) ≥ 3 points or the partial Mayo score ≥ 3 points, following a response to infliximab induction therapy where a 3-point reduction was seen in the HBI or partial Mayo score.
Measure: time to infliximab loss of response Time: 1 yearDescription: measured from the time of treatment initiation to the time of cessation as decided by the treating physician.
Measure: time to infliximab discontinuation Time: 1 year