Treatment of Impending Tumor Lysis with Single-Dose Rasburicase

OBJECTIVE: To report the experience of using rasburicase as a single-dose treatment for childhood leukemia presenting with hyperuricemia. CASE SUMMARIES: Three children with acute lymphoblastic leukemia presenting with hyperuricemia received rasburicase as a single intravenous dose just prior to the start of chemotherapy. This was followed by rapid reduction of serum uric acid levels within 24 hours, which remained low throughout induction therapy while allopurinol and hydration therapy without urinary alkalinization ensued. Subclinical tumor lysis was evidenced by the appearance of hyperphosphatemia and hypocalcemia in all cases and hyperkalemia in 1 patient. These abnormalities were transient, and each patient's renal function gradually improved from pretreatment baseline without requiring dialysis. DISCUSSION: Our experience suggests that hyperuricemia in children at risk for tumor lysis can be managed with a briefer regimen of rasburicase than the recommended 5- to 7-day course. CONCLUSIONS: A shorter course of rasburicase treatment, including single-dose injection, is feasible and will improve the cost-effectiveness profile of the otherwise expensive compound.