Hypersensitivity to cetuximab: Is there an association with race, region or both?

Abstract

14002 Background: A higher incidence of hypersensitivity reactions (HSR) has been reported in the mid-southern US (22 %: O’Niel et al. JCO 2007; 24: 3644–48) as compared to the national average (≤ 4%). Our objective was to determine the rate of any HSR and grade 3 & 4 HSR in cetuximab treated patients at a university based oncology practice in the heart of the midsouth in Memphis, TN. We also attempted to identify patient, treatment, and tumor characteristics that are predictive of HSR to cetuximab. Methods: 79 cancer patients, who received cetuximab at any time during their treatment course were identified and their charts reviewed for documented HSR. Information on patient demographics, treatment history, type of pre-medication used and history of prior allergies was also collected. HSR were graded according to the National Cancer Institute Common Toxicity Criteria for Adverse Events Version 3.0. Fisher’s exact test was used to test for association between HSR and other variables. Results: Patient cohort: Median age 58 (18–85), 62% black, 61% males. The observed rate of any HSR was 8.8% (7 of 79 patients) and grade 3 & 4 HSR was 7.5%. We found no significant association between HSR and any of the following variables: age, gender, history of allergies, tumor type, prior chemotherapy or radiation therapy, and premedications used {H1 vs. H1+H2 blockers, dexamethasone (D) vs. no D}. Race was significantly associated with any HSR and grade 3 & 4 HSR (p = 0.01 and 0.02 respectively) Caucasians were more likely than blacks to experience any HSR (20% vs. 2%) and grade 3 & 4 HSR (16% vs. 2%). Conclusions: Our rate of HSR to cetuximab is higher than the national average, but lower than that observed at two other institutions in the mid-south (Chapel Hill, NC and Nashville, TN). Demographic differences between the patient populations with 62% of our patients being black as opposed to only 19% in the report by O’Niel et al could explain this. Prospective confirmation of these findings and exploration of mechanisms to this racial disparity are warranted. No significant financial relationships to disclose.