Reduced administration of rasburicase for tumor lysis syndrome: A single-institution experience.

In the present study, the dosage and duration of rasburicase administration were retrospectively evaluated for the ability to control the serum uric acid (S-UA) level in 13 patients diagnosed with hematological malignancies and tumor lysis syndrome (TLS), or those at risk of developing TLS, at the University of Fukui Hospital. At the time of diagnosis, seven patients already exhibited laboratory TLS, and three demonstrated clinical TLS. All patients received rasburicase in addition to chemotherapy agents. The median dose was 0.19 mg/kg (range, 0.13-0.25 mg/kg), and the median duration was four days (range, 1-7 days). Six patients sequentially received a xanthine oxidase inhibitor, allopurinol or febuxostat. The primary estimate was the normalization of the S-UA level at the end of rasburicase treatment and on treatment day seven. The average S-UA level prior to treatment was 10.4±4.5 mg/dl (mean ±standard deviation), and 11 out of 13 patients demonstrated a S-UA level >7 mg/dl. The S-UA level at the end of rasburicase administration was 0.5±1.5 mg/dl and the S-UA level at day seven was 1.4±1.5 mg/dl. All the patients achieved normalization of the S-UA level. On day seven subsequent to the initiation of treatment, the patients receiving rasburicase for a maximum of three days exhibited an S-UA level of 1.9±1.8 mg/dl, while the patients receiving rasburicase for longer than three days demonstrated an S-UA level of 1.0±1.3 mg/dl (P=0.20; Mann-Whitney test). The administration of 0.13 mg/kg and 0.22 mg/kg resulted in comparable UA level reductions. The administration of allopurinol or febuxostat following rasburicase administration suppressed the re-increase in S-UA level. Therefore, it was concluded that reduced administration of rasburicase successfully controlled the S-UA level in TLS.