Fixed, low-dose rasburicase for the treatment or prevention of hyperuricemia in adult oncology patients.

Purpose: Rasburicase is a recombinant urate oxidase enzyme administered to high risk patients or to those with preexisting hyperuricemia from tumor lysis syndrome (TLS). The objective of this retrospective review is to evaluate and characterize the use of fixed, low-dose rasburicase for the treatment of hyperuricemia in adult patients.

Patients/methods: A retrospective chart review from 1 October 2005 to 31 December 2011 was conducted in adult oncology patients who received fixed, low-dose rasburicase. Patients who met the inclusion criteria were evaluated for the uric acid level change from baseline and the achievement of uric acid level less than 8 mg/dL.

Results: Forty-five patients were included in the analysis in which 26 (58%) patients received 3 mg rasburicase. For the 39 patients with baseline uric acid levels 8 mg/dL or higher, 80% achieved a uric acid level lower than 8 mg/dL with a single rasburicase dose. Six patients (13%) required renal replacement therapy despite rasburicase. The median uric acid level reduction 24 h post rasburicase dose 1.5 mg, 3 mg, 4.5 mg, and 6 mg were 5.5, 5.8, 3.8, and 10.05 mg/dL, respectively. There was no clinical difference between obese and non-obese patients in terms of their median uric acid reduction, 5.5 vs. 7 mg/dL, respectively.

Conclusion: Fixed, low dose rasburicase produced a consistent lowering of uric acid levels and may be utilized in the management of hyperuricemia in TLS. Further study is necessary to determine if a larger fixed dose would be required in those patients with a higher baseline uric acid level.