Fixed-Dose Rasburicase in Overweight and Obese Patients Versus Normal-Weight Patients

Fixed-dose rasburicase (FDR) is common practice in treating hyperuricemia associated with tumor lysis syndrome in adults; however, there is a lack of data regarding the effectiveness of this dosing strategy specifically in the overweight and obese patient populations.

To determine if patient weight per body mass index (BMI) category is associated with failure of initial FDR as defined by the need for additional dose(s) based on a uric acid level (UAL) ≥7.5 mg/dL within 10 days of previous rasburicase administration.

Adults who received FDR per institutional guidelines from October 2008 to August 2013 were reviewed. Patients had either a baseline UAL ≥7.5 mg/dL or were considered high risk (leukemia or lymphoma diagnosis with white blood cell count >50 000/mm³ or lactate dehydrogenase level greater than 2 times the upper limit of normal). Patients were stratified by BMI as underweight (<18.5), normal (18.5-24.9), overweight (25-29.9), or obese (30+).

Overall, 12 out of 151 patients who received FDR required a repeat dose of rasburicase. The percentage of patients requiring a repeat rasburicase dose was not different between obese/overweight versus normal/underweight patients (8.7% vs 6.4%, P = 0.75). Similarly, there was no difference between obese alone versus normal/underweight patients (12.3% vs 6.4%; P = 0.51).

In this retrospective analysis, patient BMI did not correlate with failure of FDR in adults, suggesting that this dosing strategy is efficacious in the adult population.