Weekly dosing of carboplatin increases risk of allergy in children

Background: Carboplatin (CBDCA) has been used increasingly to treat pediatr ic low-grade gliomas, Allergic reactions to CBDCA have been reported in 2% to 30% of children. The reason for this high incidence of allergy is unclea r. Methods: To determine the risk factors for CBDCA allergy, an historic cohor t study was conducted for all children who received the drug during a 6-yea r period at the Lucile Salter Packard Children's Hospital at Stanford. The patients' medical records were reviewed for data on age, tumor type, CBDCA dose schedule, total number of doses, cumulative dosage, dose per treatment , other chemotherapy administered, and allergic reaction. Results: Fifty-four children (mean age 7.2 years, 35 boys) were identified. Six children (11.1%) had an allergic reaction to CBDCA. All reactors had l ow-grade gliomas treated with weekly CBDCA and vincristine, with a dosage p er treatment <500 mg/m(2). Overall, six (75%) of eight children administere d weekly CBDCA, 6 (46.2%) of 13 children with brain tumors, and 6 (40%) of 15 administered CBDCA dosage <500 mg/m(2) manifested allergic reactions. Pa tients receiving more than five doses had significant risk for CBDCA allerg y (relative risk [RR] = 11.8; 95% confidence interval [Cl]: 1.5-94.1). Usin g logistic regression with multiple variables, weekly dose schedule was the most predictive covariate for allergic reaction (P < 0.0001), and other fa ctors were unrelated or redundant. Conclusions: Children with low-grade gliomas receiving CBDCA weekly are at significantly increased risk for CBDCA allergy. The repetitive, weekly dosi ng schedule of CBDCA appears to be a key risk factor for allergic reaction in brain tumor patients. The high frequency of allergy with weekly CBDCA wa r-rants further consideration when planning future trials.