Infliximab retreatment in adults and children with Crohn's disease: risk factors for the development of delayed severe systemic reaction.

Objectives: Although effective in the treatment of refractory Crohn's disease, episodic retreatment with the antitumor necrosis factor a chimeric monoclonal antibody infliximab (Remicade, Centocor, Malvern, PA) can be associated with severe acute and delayed systemic reactions.

Methods: We analyzed episodic infliximab retreatment over 30 months in 86 adult and pediatric patients receiving 304 infusions to determine factors associated with the development of severe systemic reaction.

Results: Overall, 14% of patients experienced severe systemic reactions with episodic infliximab retreatment. There was a significant difference in the rates of severe systemic reaction observed in adults (11/52 [21%]) and pediatric patients (1/34 [3%]) (p < 0.02). Delayed systemic reactions, characterized by arthralgia, fever, and myalgia requiring corticosteroid treatment, were found exclusively in adults (age > 17 yr) and occurred in eight patients treated for luminal Crohn's disease. Acute systemic reactions, characterized by hypotension, mucosal irritability, and laryngospasm requiring epinephrine, diphenhydramine, and/or methylprednisolone treatment, occurred sporadically in three adults and one child, treated for both luminal and fistulizing disease. Second infliximab infusions were associated with two thirds of severe systemic reactions, and a distant second infusion (> or = 20 wk from first infusion) was poorly tolerated relative to earlier retreatment (p < 0.001). Concomitant medications were similar in adults and children.

Conclusions: Episodic infliximab retreatment--specifically, a distant second infusion--is associated with high rates of severe systemic reaction in adults, but not children. We recommend multiple early infusions of infliximab if retreatment is anticipated in adult patients to avoid the development of delayed severe systemic reactions.