The Value Of Low, Fixed, Single Dose Rasburicase In The Prevention And Treatment Of Tumor Lysis Syndrome.

e18558 Background: Rasburicase is a recombinant urate oxidase drug approved by the US FDA for the management of hyperuricemia in Tumor Lysis Syndrome (TLS). Recommended dose of 0.2 mg/kg/day for 5 days is expensive and the benefit of extended schedule compared to a single fixed dose of 1.5 mg is not known. Methods: This is a retrospective cohort study done at a tertiary medical center including 165 (144 adult and 21 pediatrics) patients admitted between January 2013 and December 2018. We analyzed the efficacy of single low dose rasburicase 1.5 mg irrespective of bodyweight in adults and in children a dose of 0.15 mg/kg (maximum 1.5 mg) intravenously over 30 min for prevention and treatment of TLS and subsequent doses were given based on clinical and biochemical response. Plasma samples for uric acid were collected at baseline, 6–24 hrs, 48 hrs post-rasburicase, and daily during treatment. The primary outcome was achieving a uric acid level less than 7.0 mg/dl after a single dose of rasburicase in the groups. Secondary outcomes included need for repeat rasburicase doses, and a cost analysis. Results: Children accounted for 12.1% (n = 20) and adults 87.9% (n = 145). The median ages in pediatric and adult groups were 7.9 years and 54 years respectively. Rasburicase was used prophylactically in 35 (21.2%), for laboratory TLS in 105 (63.6%) and for clinical TLS in 25 (15.2%) patients. SDR prevented laboratory/clinical TLS in 89% of the prophylactic group and prevented clinical TLS in 72% of the laboratory TLS group. However, 92%(n=23) of the patients with clinical TLS required more than one dose rasburicase. The average total monthly cost of rasburicase was reduced by 96% ($2850 to $114) after adoption of the above protocol. Conclusions: Single low dose rasburicase is a highly economical and clinically effective way of managing patients with TLS and could serve as an alternative to the 5-day treatment. This dose, therefore, balances cost and efficacy of treatment.