Background/Purpose: Infliximab (IFX) is a therapeutic monoclonal antibody targeting TNFa indicated in the treatment of a number of chronic inflammatory diseases. IFX is administered by intravenous infusion and may be associated with infusion reactions (IRs).

Methods: RemiTRAC Infusion is a prospective observational registry conducted in 12 Canadian sites from 2005-2012. IFX infusions were followed to document IRs and their management, pre-medication use and adverse events. An IR was defined as any AE occurring during the infusion or within 1 hour post-infusion. The effects of concomitant medication and pre-medication prior to infusions on the incidence of IRs were evaluated by propensity score adjusted analysis using a Multilevel logistic regression model with the following variables as predictors: Patient age, weight and gender; prior enrolment use of IFX, any prior biologic use; indication; season and year of infusion; patient eligibility; dose; time since the last infusion and number of previous IRs.

Results: 1632 patients were enrolled and 24,852 infusions were recorded. The majority (63%) of patients in this cohort are treated with IFX for rheumatologic conditions such as RA (40%), AS (18%) and PsA (6%). 201/1632 (12.3%) patients reported at least one IR. Of 24,852 infusions, 322 resulted in an IR (1.3%) and most IRs were mild to moderate in severity (95%). The most common IR was pruritus, occurring in 19.9% of infusion reactions. Flushing (9.9%) and dyspnoea (6.2%) are the only other infusion AEs occurring in ≥5% of IRs. Four serious IRs (fever, itching/flushing, chest pain, chest pain/flushing) and no serious anaphylactic reactions occurred.

The effects of concomitant medications and pre-medication are shown in table 1. Neither immunosuppressive agent overall, nor do MTX or corticosteroids have any effect in reducing the incidence of IRs. In contrast, pre-medication with anti-histamines and/or steroids were associated with a significant increase in the incidence of IRs. Only the use of acetaminophen monotherapy was associated with a significant reduction in the incidence of IRs

Conclusion: This registry shows that in community-based infusion clinics, IR to IFX are uncommon and largely mild to moderate in nature. Anti-histamines, intravenous steroids and acetaminophen have been widely used to decrease the odds of IRs. However, the results of this registry demonstrate that anti-histamines¹ and steroids²are ineffective as prophylactic pre-medication. The effectiveness of acetaminophen as pre-medication suggests that most IRs are of a non-immunological mechanism.

References:

1. Wasserman et al JRheum 2004;31:1912-7.
2. Sany et al., Ann Rheum Dis 2005;64:1647–1649

Table 1: Effect of concomitant medication and pre-medication on the incidence of IRs (Propensity scores adjusted effect).