Supplementary Material for: The Incidence and Risk Factors of Infusion-Related Reactions to Rituximab for Treating B Cell Malignancies in a Single Tertiary Hospital

<b><i>Background:</i></b> Rituximab is a chimeric anti-CD20 human/mouse monoclonal antibody. As its usage has increased, there have been growing concerns about rituximab-related infusion-related reactions (IRRs). <b><i>Objective:</i></b> The aim of this study is to verify the clinical features and risk factors of IRRs by rituximab, and to help establish clinical guidelines for their prevention. <b><i>Methods:</i></b> We reviewed electronic medical records of all the adult patients who were prescribed rituximab from January 2005 to July 2010 for B cell malignancy at Seoul National University Hospital. <b><i>Results:</i></b> A total of 389 cases of IRRs by rituximab (12.5% of a total of 3,104 infusions) were identified in 281 patients (49.4% of a total of 568 patients). IRRs most frequently occurred during the first infusion (40.5%) and abruptly decreased in subsequent infusions to rates of 3-8% (p < 0.001). The incidence of IRRs in patients premedicated with corticosteroid for their first infusion was significantly lower when compared to patients not pretreated with corticosteroid prior to rituximab infusion (8.3 vs. 41.2%, p = 0.017). <b><i>Conclusion:</i></b> Almost half of all patients in the study experienced IRRs at least once during their scheduled rituximab treatment. Premedication with corticosteroid can be recommended in patients with high risk of IRR in the first infusion.