Study Objective. To determine the efficacy of a single 7.5-mg dose of rasburicase compared with single doses of 0.15 mg/kg for the prevention or treatment of hyperuricemia associated with tumor lysis syndrome.

Design. Prospective, open-label study using a historical control group.

Setting. Large, nonprofit community teaching hospital.

Patients. Seventeen hospitalized patients with cancer and hyperuricemia or a risk for hyperuricemia in the prospective group, and 23 control subjects with cancer who received a weight-based dose of rasburicase.

Intervention. Patients in the prospective group received a single 7.5-mg dose of rasburicase and were followed for a minimum of 96 hours. Control subjects received a single 0.15-mg/kg dose of rasburicase.

Measurements and Main Results. Uric acid levels were measured in all patients at baseline, at 12 and 24 hours after dosing, and then daily. In all patients receiving 7.5 mg, uric acid levels returned to normal at 12 and 24 hours. Mean uric acid levels were similar between the 7.5-mg and 0.15-mg/kg groups at 12 hours (1.9 vs 0.99 mg/dl, p=0.12) and at 24 hours (1.34 vs 1.69 mg/dl, p=0.64). Mean reductions in uric acid levels in the 7.5-mg and 0.15-mg/kg groups were, respectively, 82% and 91% at 12 hours (p=0.04) and 87% and 79% at 24 hours (p=0.35). If 26 doses of rasburicase were administered every year, a 7.5-mg dose would save $41,000/year compared with a 0.15-mg/kg dose ($15,750/10 patients treated).

Conclusions. A single 7.5-mg intravenous dose of rasburicase appeared to have effects similar to those of a single 0.15-mg/kg intravenous dose for the treatment or prevention of hyperuricemia associated with tumor lysis syndrome. This low fixed dose also has the potential to reduce costs.